Abstracts of Posters Presented at Issol '02, Oaxaca, Mexico, June 30 to July 5, 2002

ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 OAXACA, MEXICO, JUNE 30 TO JULY 5, 2002

Origins of Life and Evolution of the Biosphere 32: 405–546, 2002. © 2003 Kluwer Academic Publishers. Printed in the Netherlands. 406 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 407

PREBIOTIC ENVIRONMENTS 408 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

ATMOSPHERIC NITROGEN FIXATION RATE BY LIGHTNING AND CORONAE DISCHARGES OVER THE EARTH’S GEOLOGIC HISTORY Na Mvondo D.1,2, Navarro-González R.1, Raulin F.2,CollP.2,andMcKayC.P.3 1 Laboratorio de Química de Plasmas y Estudios Planetarios, Instituto de Ciencias Nucleares, Universidad Autónoma de México, Circuito Exterior, Ciudad Universitaria, Apartado Postal 70- 543, México D.F. 04510, Mexico; 2 Laboratoire Interuniversitaire des Systèmes Atmosphériques, Universités Paris 12 et 7 & CNRS, 61 av. Général de Gaulle, F-94010 Créteil Cedex, France; 3 Space Science Division, NASA-Ames Research Center, Moffett Field, CA 94035-1000, USA

The production of reactive nitrogen species in the troposphere by lightning and coronae discharges is the only natural source of fixed nitrogen to the biosphere today. In the early Earth, abiotic nitrogen fixation was a fundamental prerequisite for the origin and sustainability of life until the advent of biological nitrogen fixation. Reactive nitrogen could have been delivered to the early Earth by exogenous contributions or fixed by endogenous sources. It is predicted that the endogenous sources dominated the supply of nitrogenated compounds. Among these sources, electrical discharges during thunderstorm could have been an important source of reactive nitrogen (NO, NO2,andN2O) in the terrestrial troposphere. Here we report the first experimental study of the variation of the atmospheric nitrogen fixation rate by cloud-to-ground lightning and by point discharges in the ground over the whole Earth’s geologic history. The energy yields of nitric oxide, nitrous oxide and nitrogen dioxide were estimated over a wide range of atmospheric compositions, from neutral (CO2 –N2) to oxidized conditions (O2 –N2).In the absence of free oxygen, NO was identified as the sole N-product formed during lightning whereas during coronae processes N2O was produced as a secondary product. In the presence of molecular oxygen, among the nitrogen oxides produced NO2 was the predominant form.

ORIGINS OF UV-RADIATION SCREENING COMPOUNDS Bettina Heinz Palomar College, 1140 W. Mission Road, San Marcos, CA 92069 California State University San Marcos, Twin Oaks Valley Road, San Marcos, CA 92069

Present life depends on various ultra-violet radiation products for protection against genetic and other damage. such as mycosporine like amino acids (MAA’s) mela- noids, caroteinoids etc. The same protection would be required for early life forms, if not more. Pteridines have been produced by thermolysis and pyrolysis of dry amino acid mixtures (Heinz et al.) as a possible prebiotic pathway. Related compounds such as ﬂavins and acridines were also found in the reaction mixtures. The latter serve as photoactive compounds for electron transfer reactions as well as intercalating agents. However, the UV spectra of the distillates produced by the thermolysis reactions, have strong resemblance to the ones produced by micro-sporine like amino acid UV protectors. This means that amino acids are capable of forming ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 409 protective agents against ionizing radiation, which can be damaging to the fragile beginnings of life.

METEORITIC IRON-NICKEL AS A SOURCE OF CHEMICAL REDU- CING POTENTIAL AND HETEROGENEOUS CATALYSIS, BOTH WA- TER GAS SHIFT TYPE (WGST) AND FISCHER-TROPSCH TYPE (FTT), ON AN OXIDIZED/OXIDIZING EARLY EARTH S.N. Platts Cogswell Laboratory, R.P.I., Troy NY 12180-3590 U.S.A. ([email protected])

If the auto-generated condition of the late Hadean atmosphere was oxidized and essentially redox neutral (i.e.CO2;N2;H2O), prebiotic chemistry faces a fundamental redox problem: amino acids, lipids, sugars, purines and pyrimidines are all very reduced relative to carbon dioxide. The impact delivery (comets/meteorites) of exogenously-produced organics constitutes one suggested solution to the problem, and hydrothermal vent geochemistry offers another viable scenario for the accumulation of reduced organic species via FTT reactions at mineral surfaces. The present work proposes a third contribution toward the production of reduced organics in situ on the early Earth: that the delivery of large cumulative tonnages of meteoritic Fe-Ni metal to the surface would have constituted a signiﬁcant reservoir of electrochemical reducing potential towards the redox conversion of CO2 (under aqueous conditions) as the metal was effectively being redox titrated against the atmosphere. Local to the wet surface of a metallic meteoritic body under an (0) oxidized atmosphere, the oxidation of Fe by H2CO3 generates hydrogen in the Fe-Ni/CO2/H2O system which could thus access WGST chemistry (e.g.CO2 + 2H(ads) =CO+H2O). The Ni atoms would be cathodically protected by the preferential corrosion of Fe, hence nickel is expected to be redox stable while it remains electrically connected to any uncorroded iron. Nickel would thus be made avail- + + − → able to serve both as a locus for hydrogen ion discharge (H(aq) e H(ads)) and as a site for the chemisorption of CO towards the heterogeneous catalysis of FTT chemistry, and hence the generation of a suite of reduced and functionalized organic compounds.

LIQUID OR SUPERCRITICAL CO2 PHASE ON EARLY EARTH AS POS- SIBLE PREBIOTIC MEDIUM Gyula Pályi and Claudia Zucchi Department of Chemistry, University of Modena and Reggio Emilia, Via Campi 183, I-41100 MOD- ENA, Italy (e-mail: [email protected])

Model experiments exploring the possibilities of the formation of “biomolecules” under conditions supposed for the early Earth were exceptionally successful in the 20th century [1]. Some gaps, in the chain of molecular events leading from inan- 410 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 imate to animate matter are, however, not yet ﬁlled. One of these is the problem of spontaneous polycondensation (water-releasing) reactions in the presence of high excess of water (as primary requirement of life) [2]. A possible solution of this problem would be the consideration of non-aqueous media on the “primitive” Earth. Palaeoclimatological considerations [3] permit the hypothesis that liquid or even supercritical CO2 phases could have locally existed on the early Earth, providing an excellent, non-aqueous medium [4] for prebiotic reactions. Supposed physical and chemical parameters on early Earth and phase behavior of CO2 are compared in this paper, concluding, that – at least in some regions of Earth – liquid or even supercritical CO2 phase(s) might have existed. Experimental veriﬁcation of this hypothesis is in course.

References

(a) W. Löb, Ber. Deutsch. Chem. Ges. 1913, 46, 684-697. (b) O. Baudisch, Angew. Chem. 1913, 26, 612. (c) S.L. Miller, Science, 1953, 117, 528-529. (d) A. Lazcano, S.L. Miller, Cell, 1996, 85, 793–798. J. Maynard Smith, E. Szathmáry, The Major Transitions in Evolution. W.H. Freeman/Spectrum, Oxford, 1995. Chapter 3.8 (a) S. Bengtson, Early Life on Earth, Columbia University Press, New York, 1994. (b) G. Pályi, C. Zucchi, L. Caglioti (Eds.), Fundamentals of Life, Elsevier, Paris, 2002. (ISBN: 2-84299-303-9] P.G. Jessop, W. Leitner, Chemical Synthesis Using Supercritical Fluids, Wiley-VCH, Weinheim, 1999. ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 411

CHEMICAL EVOLUTION 412 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

BILATERAL SURFACE ACTIVE MINERALS AS SELECTIVE CONCEN- TRATORS, CATALYSTS, AND CELLS IN PUTATIVE PREBIOTIC REAC- TIONS – DYNAMICS AND ENERGETICS Gustaf Arrhenius and Siew Ung Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093-0236, [email protected], [email protected]

Expanding sheet structure minerals have proven effective in mediating several crucial steps in chemical evolution. They open pathways to five basic problems in prebiotic chemistry. These are: first, to bring necessarily highly dilute potential reactants from dilute solution into reactive state at high concentration (∼10M) in the mineral interlayer. Second; this concentration process is selective – essential polar- and charged species are withdrawn from a presumed pool of potentially interfering molecules. Third; the catalytic properties of these minerals facilitate constructive reactions such as aldol condensation leading to the formation of nucleoside phos- phates including, selectively, ribose-2,4-diphosphate, and to the oligomerization of nucleotides. Fourth; they provide protection against hydrolysis of sensitive species in the interstitial solution contained by the molecular sheets of the minerals. Fifth; this encapsulated solution of charged and polar reactants stands in diffusive contact with the surroundings through the slit-shaped pores provided by the openings at the crystal edges – the mineral with its reactive internal multicomponent solution may function as a first primitive cell.

FATE OF PREBIOTIC ADENINE Corey A. Cohn2, Thomas K. Hansson1, Håkan S. Larsson∗, Stephen J. Sowerby∗, Nils G. Holm∗ and Gustaf Arrhenius2 1 Dept. of Geology and Geochemistry, Stockholm University, SE 10-691 Stockholm, Sweden; 2 Scripps Inst. Oceanography, Univ. Calif. San Diego, La Jolla, CA 92093-0236 USA

The plausible prebiotically relevant synthesis of nucleic acid bases has been demonstrated in experiments utilizing HCN. However, low yields and a susceptibility to hydrolysis challenge their geologic accumulation. In the presence of minerals, adsorption may increase the yield by an equilibrium shift and provide a subsequent protection from hydrolysis by excluding water. In this study, aqueous equilibrium adsorption isotherms for the purine base adenine have been obtained on several minerals by frontal analysis utilizing HPLC at 30˚C. Results indicate a push toward adsorption with it being highly adsorbed on pyrite and quartz. The surface concentration of adenine is about 15, 5, 3.75, 1.25 times that which is in solution for pyrite, quartz, pyrrhotite, and magnetite, respectively when the solution concentration is 20 µM. This signiﬁcant adsorption could enable minerals to act as a sink for adenine resulting in increased yields and protection from hydrolysis. The adsorption of organic molecules to minerals has long been considered inﬂuential in prebiotic processes relevant to the origin of life. Our results provide further evidence for the ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 413 role of minerals in prebiotic hypotheses evoking purine bases and the development of a pre-RNA.

PREBIOTIC SYNTHESIS OF SELECTED INTERMEDIATES AND ANA- LOGS IN THE KREBS TCA CYCLE William J. Hagan Jr. and Damaris Pinedo New York Center for Studies on the Origins of Life, College of St. Rose, 432 Western Ave., Albany, NY 12203 USA

The Krebs Tricarboxylic Acid (TCA) Cycle is a hallmark of mitochondrial metabolism, but its appearance must have preceded the rise of aerobic respiration. A noteworthy observation is that anaerobic green-sulfur bacteria, including Chloro- bium limicola, possess a complete cycle that functions in reverse as a carbon- fixation mechanism1. These microorganisms rely on hydrogen sulfide as an electron donor, and they likely arose on Earth before cyanobacteria. We have been especially interested in thioacyl derivatives of succinic acid, which might drive other processes such as phosphorylation. Succinic acid has been formed in prebiotic simulations and has been identified as a major component of 2 the Murchison meteorite . Polysulfides (H2Sn) were also plausible constituents of the early ocean, as they are spontaneously formed by the reaction of HS− with elemental sulfur, itself a product of H2S photolysis in the gas phase. When a nitrogen-purged solution of 10 mM succinic acid and 50 mM Na2S in water, adjusted to pH 6.5 with HCl, was incubated for 18 h at 30oC., a 40% conversion to thiosuccinic acid [HS(CO)CH2CH2COOH] was detected by HPLC analysis on a C-18 reverse-phase column with a mobile phase of 10 mM NaH2PO4 (pH 3.5) in 10% aqueous methanol and UV detection at 200 nm. Spectroscopic and chromatographic data (to be presented) suggest a role for polysulfides in the 414 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 formation of thiosuccinic acid, which may serve as a prebiotic analog and potential precursor of succinyl CoA.

References

B. B. Buchanon and D. I. Arnon, Photosynth. Res. 24, 47–53. J. G. Lawless: 1974, et al., Nature 251, 40–41.

THE NEW YORK CENTER FOR STUDIES ON THE ORIGINS OF LIFE. ANASANSCORT William J. Hagan Jr. The College of St. Rose, e-mail: [email protected]

This Center is conducting an interdisciplinary research program on the origins of life. There are seven participants from RPI, SUNY Albany and The College of St. Rose working in the areas of astrophysics, planetary geology, chemistry and molecular biology. There are interdisciplinary overlaps between this continuum of ﬁelds where this research is being carried out as well as between more distant disciplines. Some students have more than one advisor since they are conducting interdisciplinary research. Some students are getting degrees in interdisciplinary science at RPI. There is a vibrant Journal Club of postdoctorals and graduate students that discusses research and talks to seminar speakers after the weekly seminar. The outreach program includes interviews with the seminar speakers that are broadcast on National Public Radio. In addition, the audio portion of the seminar presentations, together with the visuals used by the speaker, can be downloaded from our website (www.origins.rpi.edu). The recent seminar speakers and the titles of their lectures are listed on the poster. Students, postdoctorals and faculty participants from the Center will be present at this meeting if you have questions. Supported by NASA grant NAG5-4546.

PREBIOTIC SYNTHESIS OF 5-METHYLCYTOSINE John H. Chalmers and Stanley L. Miller Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, 92093-0506, USA, e-mail: [email protected]

Thymine is thought to have replaced uracil when DNA rather than RNA became the long-term store for genetic information (1). By using thymine opposite adenine, any uracil resulting from the deamination of cytosine could be detected and replaced, thus avoiding transition mutations. Miller proposed that DNA in which 5-methylcytosine (5MC) and uracil replaced cytosine and thymine would have the same potential for error correction as any thymine resulting from the deamination of 5MC could be detected and removed by an analogous enzyme system. ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 415

We have studied several potentially prebiotic routes to 5MC from 5-hydroxyme- thylcytosine (HMC), the condensation product of cytosine with formaldehyde. Hy- drazine has been reported to generate thymine from uracil and formaldehyde (2) and does give low yields of 5MC from HMC and of thymine from hydroxymethyl- uracil. Isopropanol under acid conditions reduces HMU to thymine by hydride tranfer(3), but did not reduce HMC to 5MC under our conditions. Yields of 5MC in excess of 50% were obtained by heating millimolar HMC with 15 M potassium formate at pH 9–10 at 135◦–150◦ C for several hours in sealed tubes. A small amount of thymine was also seen in these reactions and may result from the deamination of 5MC.

References

Lehninger, A., Nelson, D. L., and Cox, M. M.: 1982, Principles of Biochemistry, 3nd edition, Worth Publishers, NY. p. 344. Stephen-Sherwood, E., J. Oró, and A. P. Kimball: 1971, Thymine: A Possible Prebiotic Synthesis. Science 173, 446–447. Chada, M. S., A. S. Subbaraman, Z.A. Kazi, and A. S. U. Choughuley: 1978, Origin of Life, Pro- ceedings of the 2nd ISSOL Meeting, H. Noda, ed. Center for Academic Publishing, Japan. pp. 199–204.

SUBSTRATE-DIRECTED FORMATION OF SMALL BIOCATALYSTSUN- DER PRE-BIOTIC CONDITIONS Gideon Fleminger∗ and Akiva Bar-Nun ∗ Department of Molecular Microbiology and Biotechnology and Department of Geophysics and Planetary Sciences, Tel-Aviv University, Tel-Aviv, 69978, Israel

The prebiotic processes that led to the emergence of Life on Earth are still an enigma. Obviously, such complex processes could not occur without the involve- ment of specific biocatalysts. The nature and origin of these biocatalysts is widely debated from peptides randomly synthesized on mineral templates to the ribosomes of the RNA World. Nevertheless, since specific recognition is the key for any bio- catalytic process, it is inconceivable that primordial biocatalysts were formed by random assembly of monomers, e.g. amino acids. Rather, some kind of template- assistance was required. We have suggested that the variety of chemical interactions that occur between an enzyme and its substrate, including Van der Waals forces, hydrogen bonds, salt bridges and hydrophobic interactions, might have served as a driving power for the introduction of specificity into prebiotic catalysts being evolved. Thus, in a given chemical reaction, catalyst formation might be enhanced by the presence a substrate, serving as a specific template. Catalytic centers formed in such manner, could have evolved later into the ‘modern’ enzymes that form the basis of biochemical life as we know it today. 416 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

In support of this concept, we have experimentally demonstrated the capability of o-nitrophenyl galactopyranoside (ONPG) to direct the formation of a catalyst capable of cleaving it. When L-cysteine was incubated at elevated temperatures, in the presence of ONPG, with Fe+2 ions, dicyandiamide (DCDA) as a condensing agent and 2-mercaptoethanol (2-ME) as a reducing agent, a catalytically-active dipeptide was formed. This peptide failed to form when either ONPG, DCDA, 2- ME or Fe+2 ions were eliminated from the reaction mixture or when Fe+2 ions were replaced by Fe+3. The active compound was isolated and purified by HPLC and identified by a series of chemical and structural analyses, as Cys-Cys to whose two thiol groups a Fe+2 ion was bound. It was shown to cleave ONPG, but not the p-nitro isomer, in a catalytic manner. When cysteine was replaced in the reaction mixture by a series of chemically modified cysteine derivatives it was found that the blocking of either N or C termini of the dipeptide did not affect its activity. In contrast, blocking the cysteines SH groups resulted in the loss of the activity. Molecular imaging analysis suggested that the presence of ONPG directs formation of a dipeptide with a cis, rather than trans conformation which is required to obtain an active Fe-containing dipeptide. This analysis also suggested a mechanism for substrate hydrolysis by the dipeptide. Our next goal was to demonstrate the ability of the isolated peptide to catalyze the formation of ONPG from ONP and galactose. Since formation of the glycoside bond involves the elimination of water it was advisable to perform the reaction in a water-free organic solvent. An immobilized form of active dipeptide was prepared in two stages: 1) Cysteinyl-glass beads were prepared by coupling the amino group of L-cysteine to aminopropyl glass beads by a glutardialdehyde reaction followed by borohydride reduction, and 2) the resulting beads were incubated with either L-cysteine or cysteine-methylester, in the presence of ONPG, DCDA, 2-ME and Fe+2 ions. As a result, an immobilized “enzyme” was formed, covalently coupled to the glass beads via the dipeptide N-terminus. This preparation was active in the hydrolysis of ONPG similar to the “soluble enzyme”. Incubation of the immobilized preparation with ONP and radio-labeled galactose in dry ethanol for three days at 50oC, resulted in time dependent appearance of radio-labeled ONPG.

References

Kochavi et al., (1977) Substrate directed formation of small biocatalysts under prebiotic conditions, J. Mol. Evol. 45, 342–351. ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 417

METEORITIC TRANSITION METALS AND PROPERTIES OF PREBI- OTIC ATMOSPHERIC AEROSOLS Daniel K. Havey, and Veronica Vaida Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309 USA

Recent ﬁeld measurements have yielded surprising information concerning the composition of atmospheric aerosols. These results show a very high (10–50%) content of insoluble organic molecules along with an amazing diversity of 46 elements, many of which are transition metals. Some of these metals are anthropo- genic but the majority was shown to have a meteoric origin. The presence of these metals introduces the possibility of interesting organometallic compounds forming upon reacting with the aerosols. We point out that the coagulation of meteoric aerosols from the lower stratosphere with organic ones from the upper troposphere would have supplied metal catalysts to prebiotic organic chemistry. Laboratory studies will be reported showing the implications of chemistry involving transition metals in the Earth’s climate and prebiotic chemistry.

References

Murphy, D. M., Thomson, D. S. and Mahoney, M. J.: 1998, In Situ Measurement of Organic, Met- eoritic Material, and Other Elements in Aerosols at 5 to 19 Kilometers, Science 282, 1664–1669.

ATMOSPHERIC AEROSOLS AS PREBIOTIC CHEMICAL REACTORS V. Vaida Department of Chemistry and Biochemistry, University of Colorado, Boulder CO 80309 USA

The high organic content of individual upper tropospheric aerosol particles measured from the WB57F high altitude aircraft leads to an inverted micelle structure, with the polar aqueous core contained within a film of amphiphilic molecules with their polar heads bound to the surface of the core and their hydrophobic tails exposed to the air. This model aerosol is then explored (Dobson et al., 2000) as a reaction medium in prebiotic chemistry. We suggest that their versatility eventually led to unicellular life. The emergence of several key properties of unicellular life is shown to be addressable in principle,including size, structure, composition, and replication of chemical populations. We examine the prebiotic applicability of our recent analysis (Donaldson et al., 2001) of the fission of an atmospheric aerosol particle coated with an organic film. The size of the parent particle is determined by the balance between aerodynamics and gravity, while the ratio of the radii of the daughters is determined by the compression characteristics of the amphiphilic molecules comprising the parent film. For an Earth atmosphere of one bar surface pressure, the larger and smaller daughters have the sizes of a single-celled bacterium and of a virus respectively. 418 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

References

Dobson, Ellison, Tuck and Vaida: 2000, Proc. Nat. Acad. Sci. 97, 11664–11668. Donaldson, Tuck and Vaida: 2001, Phys. Chem. Chem. Phys. 3, 5270–5273.

ADENINE IN MINERAL SAMPLES: DEVELOPMENT OF A METHODO- LOGY WITH SURFACE ENHANCED RAMAN SPECTROSCOPY (SERS) AND RAMAN MICROSCOPY FOR PICOMOLE DETECTIONS El Amri Chahrazade1, Baron Marie-Hélène2 and Maurel Marie-Christine1 Institut Jacques Monod, Biochimie de l’Evolution et Adaptabilité Moléculaire, Tour 43, 2, Place Jussieu 75251 Paris Cedex, France; Laboratoire de Dynamique Interactions et Réactivité, UMR 7075 CNRS, 2, rue Henri Dunant, F-94320 Thiais, France.

Study of interactions of biological macromolecules with mineral surfaces are of crucial interest either for understanding primeval metabolic processes and for detection of traces of living activities. Also, the exploration of Mars requires to perfect fast methods, highly resolvent, non-destructive, for either in situ analysis and for samples return analysis on earth. A prerequesite for implementation on real samples is the development of a rational methodology based on mineral models to which a controlled proportion of nucleic acids or monomers will be added. Another stake is to detect the smallest quantities. Surface Enhanced Raman Spectroscopy (SERS) and Raman microscopy are techniques of choice to study samples slightly concentrated – one can detect 10−12 moles –. SERS also gives information on the structure of molecules adsorbed on an adapted surface, as silver for example. We begin to study several model mineral such as clay, meteorite etc. Study of nucleic acids transfer from the mineral phase to the colloidal phase (for SERS) have been carried out, and we determine the threshold concentration for each type of minerals. Here, we present the results concerning the adsorption and detection of the adenine nucleic base on a serie of minerals including clay and meteorite. Results show that a combination of SERS effect and Raman microscopy is essential for an optimal detection up to 10−3 picomoles. pH effects on adsorption and detection are also presented.

THE ROLE OF BORON IN THE CHEMICAL EVOLUTION Vily Marius Cimpoiasu and Romulus ScoreiUniversity of Craiova, Biochemistry Depart- ment, A.I.Cuza13, 1100 Craiova, Romania

In our theory, the chemical system that had accommodated the origins of life evolved on interface or surface. The most obvious one is gel-sol interface, because it is macroscopic. At this interface, a strong change occurs in electrical and magnetic properties of molecules, thus modifying the chemical reactivity. ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 419

We will show that boron is involved in many pre-biotic processes, despite its low natural distribution in the early stages of the beginnings of life. We have approached the demonstration in the following ways: 1. An experimental laboratory simulation of sol-gel transition showed that hydration levels mediate and reverse the phase of the system. Moreover, the borate compounds, which act as structure makers and structure stabilizers, are capable of reversing phase by modifying the hydrophobic force between water and the polymer chain. 2. An experiment measuring the decomposition rate of D-glucose and D-ribose showed that this rate is low in the presence of borate at 80–100 degrees C, thus leading to the conclusion that the borate protects sugar rings against thermal degradation. 3. A similar experiment showed that the presence of borate in complex solutions of sugar and amino-acids inhibit Maillard reaction by forming stable borate esters with cis-diol on furanose rings, thus making possible the chemical evolution in aqueous media of sugar and amino-acids, simultaneously, at temperatures of 80–100 degrees C. 4. An experiment for synthesizing f-ribo-borate and f-fructo-borate compounds showed that in the presence of the borate, the furanoses forms of sugar become thermodynamically favorable and thus the chemical evolution scenario is veriﬁed.

HOW THE CHEMICAL PHYSICS OF THE MICROSCALE DRIVES PRE- BIOTIC CHEMICAL EVOLUTION Louis Lerman Department of Chemistry, Philipps University, Marburg, Germany, e-mail: [email protected]

Whether Earth, Mars, Titan, or Europa...in the search for life and its origins the chemical physics of the air-water interface provides length and time scales unique in their support of chemical evolution. These length and time-scales are those of naturally-occurring surface-catalyzed heterogeneous chemistry; and can create on any planetary body (having even intermittent water) a global laboratory of combinatorial chemistry. On the contemporary Earth these processes are embodied in the bubble-aerosol cycle which includes bubble formation and the adsorption of surface-active materials, bubble dissolution, and the non-equilibrium dynamics of bubble bursting. This leads to the formation of aerosols and their subsequent roles in atmospheric condensation. ’Membrane-like’ phase boundaries are created at each node of this cycle, selectively concentrating organics and metal ions. On the contemporary Earth the bubble-aerosol cycle is the largest transporter of organic matter, in both particle number and total mass, between the atmosphere and the ocean; and generates the principle nodes of heterogeneous organometallic 420 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 chemistry in each regime. In so doing the bubble-aerosol cycle provides a unique infrastructure for the concentration and transport of organic compounds, metal ions, and mineral catalysts; coupled to a rapid sequencing of hydration-dehydration events. This concentration of organics, metals, and catalytic surfaces in micro- environments undergoing multiple cycles of hydration-dehydration would seem ideal for multiple-stage polymerization. Natural consequences of the terrestrial bubble-aerosol cycle are objects with properties fascinatingly akin to those of ‘nanobacteria’: in particular the basic morphology (spheres and sausages), gross chemistry (suites of organics along with metals), and size distributions (nanometers to microns). Whether of biological or bubble-aerosol origin, these striking similarities reﬂect the universality of the chemical physics of the interactions of charge-polarized organic amphiphiles at an air-water interface. For speciﬁc applications to Mars, please see the accompanying abstract in this volume.

THE REDUCTION OF NITROGEN TO AMMONIA BY FERROUS HY- DROXIDE David Mauzerall and Irene Zielinski-Large Rockefeller University, New York, NY 10021, USA

The consensus that the atmosphere of the early earth was not highly reducing has brought out the problem of the origin of the reduced carbon and nitrogen critical to the chemical origin of life. A powerful source of reducing power on the early earth is the ferrous ion for which there is ample evidence of its presence. The reduction potential of the iron ion is highly dependent on its surrounding ligands. In particular the compound ferrous hydroxide has been shown to reduce water to hydrogen both thermally (Schrauzer and Guth, J. Am. Chem. Soc. 98, 3508, 1976) and photochemically (Braterman, Cairns-Smith and Sloper, Nature 303, 163, 1983; Borowska and Mauzerall, Origins of Life 17, 251, 1987). Schrauzer and Guth also claimed the reduction of nitrogen to ammonia specifically at pH 8.5, but these results were not verified. After many attempts we have evidence for this reaction valuable for chemical Origin of Life scenarios. The major problem has been variable backgrounds of ammonia from all components of the experiment. Illumination of 30 mM ferrous hydroxide, pH 7.5–8.5 at 25C under flowing N2 with a Xe arc lamp, >320 nm, for 15 min produced 30 nmoles of NH3. The dark reaction during this period produced 1–2 nmoles of NH3 over the same amount found in blank reactions eg at pH 4. A large amount of H2 was produced during the illumination. Thus near UV light causes the reduction of N2 to NH3 by ferrous hydroxide. Supported by NSF grant MCB-9904522. ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 421

SEQUENCE SELECTIVITY IN THE THREE-MERS FORMED IN THE MONTMORILLONITE CLAY CATALYZEDREACTION OF RNA DIMERS (pNpN) WITH THE 5’-PHOSPHORIMIDAZOLIDES OF NUCLEOSIDES (ImpN) Shin Miyakawa and James P. Ferris New York Center of Studies on the Origins of Life and the Department of Chemistry, Cogswell Laboratory, Rensselaer Polytechnic Institute, Troy, NY 12180, USA

Catalysis was important in the origins of life as demonstrated by the montmorillonite clay-catalyzed synthesis of RNA from the 5’-phosphorimidazolides of nucleosides (ImpN: N is A, G, C, and U). Adenylic acids of length 40 and more can be synthesized by the clay-catalyzed reaction. This length may be long enough for the RNA to have been a catalyst and store genetic information. A next interest would be whether there is sequence selectivity in the oligomers formed or is it a mixture of all possible isomers. In the present study, the sequence selectivity of three-mers synthesized by the clay-catalyzed reaction was investigated. A reaction of a mixture of ImpA, ImpG, ImpC, and ImpU is expected to be too complicated to analyze the obtained oligomers. Instead the reactions of dimers and monomers performed was studied, such as a reaction of pApC with ImpA, ImpG, ImpC, and ImpU. After puriﬁcation by HPLC, the sequences of three-mers were determined by enzymatic hydrolyses. This ﬁnding and those in the poster of E. Hebrard and J. P. Ferris were used to reach conclusions about the sequence selectivity in three mers. It was found that some three-mers are selectively synthesized. These results and further investigation of longer oligomers may give us important information about the sequences of these potential ribozymes.

PREBIOTIC SYNTHESIS OF NUCLEIC ACID BASES FROM CO-N2-H2O GAS MIXTURES Shin Miyakawa1, Hiroto Yamanashi1, Kensei Kobayashi1, H. James Cleaves2 and Stanley L. Miller2 1 Department of Chemistry and Biotechnology, Yokohama National University, Yokohama 240-8501, Japan; 2 Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093-0506, USA

The Earth is claimed to have had a CO2-dominant atmosphere around the time life originated, because it is thought that the primitive volcanic gases were composed of CO2,N2 and H2O. A dense CO2 atmosphere could have compensated for the low luminosity of the young sun to keep the Earth above freezing. However, there is no deﬁnitive geologic evidence for this claim, and bioorganic compounds are not efﬁciently synthesized from CO2 atmospheres. Here we discuss the composition of the atmosphere when life originated from the point of the view of chemical evolution. We suggest that the atmospheric ratio 422 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 of CO may have been much higher than previously thought. Since recent research suggests that the continental crust and oceans may have formed by 4.3 billion years ago, CO2 precipitation as CaCO3 or MgCO3 could have started before life originated. This suggests that the partial pressure of CO2 in the primitive atmosphere when life originated may have been much lower than has been estimated. CO might have been delivered or produced by impacts of extraterrestrial materials.

THE COLD ORIGIN OF LIFE: NUCLEIC ACID BASES PRODUCED FROM FROZEN HCN SOLUTIONS Shin Miyakawa1, H. James Cleaves2 and Stanley L. Miller2 1 Department of Chemistry and Biotechnology, Yokohama National University, Yokohama 240-8501, Japan; 2 Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093-0506, USA

It is suggested that life originated in a hot environment based on analysis of phylogenetic trees, the discovery of life near hydrothermal vents, and oxygen isotopic records. Biomolecules are, however, rather unstable at high temperature. Here we show that low temperatures would have been more favorable for synthesis of pyrimidines and purines if they had been endogenously synthesized via HCN polymerization. The steady state concentration of HCN over the range of 0–200 ◦C and pH 0–14 were estimated using hydrolysis rate data and an estimated atmospheric production rate of HCN. It is suggested that the steady state concentration of HCN would have been too low to polymerize in a warm primitive ocean and that eutectic freezing might have been required for the concentration of HCN to synthesize nucleic acid bases (1). It was also shown that a large variety of pyrimidines and purines are synthesized by eutectic freezing of a dilute ammonium cyanide solution, which had been frozen at –78 ◦C for 27 years (2). It is suggested that cold conditions on the primitive Earth would have been required if HCN polymerization was important for the origin of life.

References

S. Miyakawa, H. J. Cleaves and S. L. Miller, Origins Life Evol. Biosphere, in press. S. Miyakawa, H. J. Cleaves and S. L. Miller, Origins Life Evol. Biosphere, in press. ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 423

THE PREBIOTIC SYNTHESIS OF NUCLEOSIDE ANALOGUES FROM MIXED FORMOSE REACTIONS: IMPLICATIONS FOR THE FIRST GE- NETIC MATERIAL H. James Cleaves II1,2 and Stanley L. Miller2 1 Scripps Institution of Oceanography; 2 University of California, San Diego La Jolla, CA 92093- 0506

Life may have begun with a replicating polymer of RNA1,2,3. Objections to this theory have been raised based on the instability of RNA and the difﬁculty of its prebiotic synthesis4. Alternatives which are more easily synthesized prebiotically have been proposed5,6,7. Reaction of the nucleobases with a mixture of formaldehyde and acetaldehyde rapidly produces a number of isolable derivatives as well as a polymer of undetermined composition. The mechanism and kinetics of this reaction were investigated. The identity of many of the products was determined. The reaction is somewhat regioselective. The reactions proceed at low temperature and at high dilution (< 1 mM) under mildly basic and neutral conditions. The reaction can be initiated by eutectic freezing. While the nucleobases are consumed quickly in these reactions, ribosides and deoxyribosides are not formed in detectable amounts (< 10−2 %). The stability of some of the products was investigated. The importance of these ﬁndings for the prebiotic synthesis of DNA and RNA, and the origin of life, are discussed.

References

Woese, C. R.: 1967, The Genetic Code; the Molecular Basis for Genetic Expression. Harper and Row, NY. Crick, F. H. C.: 1968, J. Mol. Biol. 38, 367–380. Orgel, L. E.: 1968, J. Mol. Biol. 38, 381–393. Joyce, G. F., Schwartz, A. W., Miller, S. L. and Orgel, L. E.: 1987, Proc. Nat. Acad. Sci. USA 84, 4398–4402. Nelson, K. E., Levy, M. and Miller, S. L.: 2000, Proc. Nat. Acad. Sci. USA 97, 3868–3871. Cheikh, A. and Orgel, L. E.: 1990, J. Mol. Evol. 30, 315–321. Tohidi, M. and Orgel, L. E.: 1990, J. Mol. Evol. 30, 97–103.

BIASED SYNTHESIS IN CHEMICAL EVOLUTION STUDIES A. Negron-Mendoza1 ,S.Ramos-Bernal1, G Mosqueira2 and D. Frias3 1 Instituto de Ciencias Nucleares, UNAM, A.P. 70-453, Mexico, D.F 04510; 2 Dirección General de Divulgación de la Ciencia, UNAM. Cd. Universitaria, A.P. 70-487, 04510 México D.F., México; 3 Universidad Statual de Santa Cruz, Brazil

For the appearance of life a physical and chemical preamble was needed. Today, there are a large variety of experimental data to support the hypothesis for the abiotic formation of organic compounds. Although much knowledge has been gain, still many questions remain. 424 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

One important factor in chemical evolution are biased synthesis. These led a selectivity in the formation of organic compounds in order to reach the complex system that we call life. In this paper we propose a simple chemical system, decarboxylation of fatty acids, or deamination of amino acids that follow a preferential pathway over others possibilities in which both solid surfaces and radiation play an important role. Fatty acids undergoes a complex decomposition in the presence of radiation. Thus, radiation-induced reactions produce dimers and oligomeric products. Fatty acids present a very slow decarboxylation in the presence of montmorillonite alone. The reaction is accelerated at higher temperatures, but it is enhanced in many folds in the presence of ionizing radiation. Drastically, the normal way of radiation- decomposition reactions changes if the system contains a clay mineral. The apparent effects of the clays consist in decreasing the yield of oligomeric products and to greatly increases the yield of decarboxylation product. In this ox- idative pathway, the catalysis involve the conversion of the organic molecule to a reactive intermediate where the clay mineral accepts an electron from the acid. The crystal edges are involved in the reaction. Clays deﬁnitely affect the radiation- chemical reactions occurring in the vicinity, and their participation induce a bias in the reaction mechanism. Kinetics and energetic factors have been analyzed to understand the process that gives rise to this preferential pathway that are important for chemical evolution.

STABILITY OF ADENINE ADSORBED IN A CLAY MINERAL IN A HIGH RADIATION FIELD A. Guzmán, A. Negrón-Mendoza and S. Ramos-Bernal Instituto de Ciencias Nucleares, UNAM, Circuito Exterior 04510, Mexico D:F: Mexico

Clay minerals are considered important in chemical evolution due to their properties, ancient origin, and wide distribution. To extend the knowledge of their role in the prebiotic epoch, the adsorption and the protection role toward irradiation were studied. The attempt of this work is to show preliminary results about the studies of the stability of adenine, adsorbed in a clay mineral and exposed to a high radiation ﬁeld. The results obtained show that the gamma irradiation of aqueous adenine is pH dependent. the irradiation of adenine-clay system showed that the adenine resist a high dose of radiation in comparison with the irradiation of adenine without clay. ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 425

FORMATION OF BIOORGANIC COMPOUNDS AND PREBIOTIC CATA- LYSTS VIA COMPLEX ORGANIC COMPOUNDS MADE FROM PRIMIT- IVE ATMOSPHERES Kensei Kobayashi, Hiroto Yamanashi, Akihiro Ohashi and Takeo Kaneko Department of Chemistry and Biotechnology, Yokohama National University, Hodogaya-ku, Yoko- hama 240-8501, Japan (E-mail: [email protected])

In the conventional scenario of chemical evolution, the following steps are hypothesized in prior to the formation of prebiotic catalysts: (i) Simple precursors of bioorganic compounds like HCN and HCHO were formed. (ii) They reacted together to form bioorganic monomers such as amino acid. (iii) They were condensed to be oligopeptides, nucleosides, nucleotides and oligonucleotides. (iv) Fi- nally proto-enzymes (or proto-ribozymes) were formed in the course of molecular evolution of oligomers. It has been proved that the above scenario has many problems: For example, the formation of peptides and nucleosides from primitive atmospheres has not been proved. We here propose an alternative scenario through laboratory simulation experiments. In these days, the primitive Earth atmosphere was suggested to be a mixture of carbon dioxide, carbon monoxide, nitrogen and water. When such kind of gas mixture was irradiated with high-energy particles, very complicated mixture of organic compounds was formed. Estimated molecular weights of these complex organics are ca. 1000. These complex organic compounds had catalytic activities including phosphomonoesterase activity. When they were acid-hydrolyzed, a wide variety of amino acids and uracil (one of nucleic acid bases) were formed [1, 2]. It is also suggested that sugar-like compounds (reducing polyols) were also formed in the hydrolysates. The present results suggest a new scenario of chemical evolution: Complex organic compounds were directly formed in the primitive atmospheres. They contained primitive catalysts (proto-enzymes). Constituents of the present bioorganic compounds were also formed after hydrolysis of the complex organic compounds in ocean. Then, the primitive catalysts would evolve themselves by using these molecular parts. It is of great interest to ﬁnd out autocatalytic molecules in the pool of the complex organic compounds.

References

K. Kobayashi et al.: 1998, Origins Life Evol. Biosphere 28, 155–165. K. Kobayashi and T. Tsuji: 1997, Chem. Lett., 1997, 903–904. 426 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

A NEW METHOD FOR AN ABIOGENIC SYNTHESIS OF PYRIMIDINE NUCLEOSIDES AND THEIR ACYCLIC ANALOGUES Michael B. Simakov Group of Exobiology, Institute of Cytology RAS, Tikhoretsky Av., 4, St .Petersburg, 194064, Russia

There are many unresolved problems in abiogenic synthesis of nucleosides: (1) the absence of a feasible prebiotic pathway to the ribose; (2) the instability of this sugar; (3) the lack of efﬁcient procedures for the synthesis of glycosidic bonds. Therefore alternative genetic macromolecules such as peptide nucleic acids (PNA) and some others have been proposed instead primordial RNA. We would like to propose a feasible pathway for an abiogenic synthesis of pyrimidine PNA monomers and other nucleoside analogues along with the usual nucleosides. Such acetic acid derivatives as uracil-N’-acetic acid, thymidine N’- acetic acid, and cytosine N’-acetic acid are readily synthesized in the photochemical reaction of nucleic acid bases (U, T, and C) with the simplest amino acid glycine at the action of UV-light (λ=254 nm) in a water solution with good yields. The reaction of nucleic acid bases with such amino acid as β-alanine and β- or γ -aminobutyric acids, which are very common in meteorites, also yields a row of the base-N’-alkyl acid derivatives. Besides, α,γ -diaminobutyric acid forms an aspartate-derived nucleoside analogue which could serve as a base monomer for the ﬁrst genetic material which has similarity with peptides (peptide bond between carboxylic group of one molecule and α-aminogroup of the other) and nucleic acids (heterocyclic bases at γ -aminogroups). This type of reaction could also be used for synthesis of such acyclic nucleoside analogues as (1) glycerol-derived acyclonucleoside [Base + H2N-CH2- CH2(OH)-CH2(OH)], this compound phosphorylated at one or both hydroxyl positions could make a backbone with phosphate bonds; (2) acrolein-derived nucleoside analogues [Base+HOCH2CH(CH2NH2)CH2OH]; (3) common nucleosides [Base + ribosylamine] (it is an one step process of glicoside bond forming with good yields and great similarity with the processes of the de-novo pyrimidine nucleosides biosynthesis). So proposed reaction of the photochemical synthesis of alternative genetic monomers in aqueous environments from nucleic acid bases and compounds having amino-group is a plausible pathway for the origin of the pre-RNA world on our planet.

PYRAZINE HETEROCYCLIC STRUCTURE AS AN INALIENABLE PAR- TICIPANT OF PREBIOLOGICAL AND BIOLOGICAL PROCESSES Taisiya A. Telegina A.N.Bach Institute of Biochemistry RAS, Leninsky Prospekt 33, Moscow, 119071, Russia, e-mail ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 427

Pyrazine structure makes a functional core of coenzymes for electron and one- carbon group transfer and some photoreceptors. This structure was present in the compounds available from abiogenic processes. According to our results, the formation of pyrazine-containing substances, melanoidins and flavins, accompanied thermolytic condensation of amino acid mixtures, whereas UV-irradiation of acetaldehyde in presence of ammonia led to accumulation of melanoidins and, likely, pterins. The melanoidins formed could catalyze redox reactions and photosensit- ize amino acids polymerization. The functional versatility of pyrazine heterocycle is conditioned by its electronic configuration, i.e. the presence of aromatic π- system interacting with free electrons of N-atoms and a closeness of energy levels of S1 and S2 excited states. Such a structure easily transits to stable quinonoide (semiquinone) with a further 2e– reduction and can covalently bind organic radicals to N-atoms. Photoexcited pyrazines are active in energy and electron transfer. The pyrazine ñore retains its principal catalytic and photosensitizing functions in pterin and flavin coenzymes, though the ‘addition’ of pyrimidine and benzene rings hyperchromically shifts the molecule’s absorption maximum. We demonstrated that photoexcited pterins and folate in aqueous solution and in presence of electron donors generated free radicals, and pyrazine moiety played a key role – in their further 2e reduction. The photoexcited folate transited to H4-form and (in presence of HCOOH) formed methenyltetrahydrofolate (MTHF), thus mimicking the enzymatic transformation of folates. The principles of evolutionary selection of MTHF for a chromophore function in DNA photolyase are discussed. Supported by Russian Foundation for Basic Research Grant 01-04-48268.

RECOGNITION OF GMP, UMP AND CMP FROM AMP BY SERINE CON- JUGATE Chang-Xue Lin, Bo Han, Zhi-Hui Qin, Chang-Mei Cheng, Yu-Fen Zhao∗ The Key Laboratory of Bioorganic Phosphorus Chemistry, Ministry of Education, China Department of Chemistry, School of Life Sciences and Engineering, Tsinghua University, Beijing 100084, China

Amino acid-nucleoside conjugate is probably a very important compound in the molecular evolution. Its characters, including stability, reactivity and interaction between them, are worthy to be known. In this paper, serine conjugates of 5’-nucleotide were synthesized and their stabilities were investigated. It was found that CMP, GMP and UMP serine conjugate derivatives showed distinct chemical property as compared to the corresponding AMP derivative. When treated with one equivalent of NEt3, Ser-5’-AMP, O-isopropyl O-(2’, 3’-isopropylidene)adenosin-5’-yl N-phosphoryl serine methyl ◦ ester, was stable at 25 C for one week in anhydrous CH3CN. However, the corresponding Ser-5’-UMP, Ser-5’-CMP and Ser-5’-GMP were completely dephos- phorylated at 25 ◦C after 48 h in the same reaction media. After systematically study by 31P NMR stack, 1H NMR, ESI-MS, FT-IR, semi-empirical computa- 428 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 tion, the mechanism for intramolecular dephosphoryaltion of serine-conjugated- 5’-UMP , GMP and CMP was proposed in Figure 1.

Figure 1. Proposed catalytic route for the de-phosphorylation of serine-conjugated 5’-UMP, CMP and GMP.

This discovery may be used to explain why nature chose ATP but not else to be a highly energy material, because only AMP was stable when a conjugate was formed.

Acknowledgements

The authors would like to thank the ﬁnancial supports from the Chinese National Natural Science Foundation (No. 20175026, 20132020), the Chinese Ministry of Science and Technology, the Chinese Ministry of Education and Tsinghua Univer- sity.

References

Narlikar, G. J. and Herschlag, D.: 1997, Annu. Rev. Biochem. 66, 19. Perrotta, A., Shi, l.-h. and Been, M. D.: 1999, Science 286, 123. Nakano S., Chadalavada, D. M. and Bevilacqua, P. C.: 2000, Science 287, 1493. ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 429

PEPTIDE SELF-FORMATION FROM CONJUGATE OF NUCLEOSIDE AND AMINO ACID Chang-Xue Lin, Chang-Mei Cheng, Zhi-Hui Qin, Yu-Fen Zhao∗ The Key Laboratory of Bioorganic Phosphorus Chemistry, Ministry of Education, China Department of Chemistry, School of Life Sciences and Engineering, Tsinghua University, Beijing 100084, China

In the study of origin of life, protein world1, RNA world2 and co-evolution3 hypothesis have been proposed. After systematically study in our laboratory, N- phosphoryl amino acids were proposed as a model for co-evolution of protein and nucleic acid4. Our previous work showed that N-(O,O’-dialkyl)phosphoryl ?- amino acids could activate themselves by formation of an intramolecular phosphoric- carboxylic mixed anhydride, in which the carbonyl group was activated by the phosphoryl group, so that the amino group of another amino acid could attack it to form a peptide. Based on these results, we further want to know what would been happened if the alkyl group in N-(O,O’-dialkyl) phosphorlylα-amino acid is replaced by a nucleoside residue. So some conjugates of amino acid and nucleoside were synthesized by the modified Atherton-Todd reaction. At the same time, the peptide formation was also studied. When heated in anhydrous methanol at 40 ◦Cfor 72 hours, the solution of conjugates of amino acid and nucleoside were identified by electrospray ionization mass spectrometry(ESI-MS). It was found that dipeptides and tripeptides linked with nucleoside were formed (Figure 1). Their structures were further identified by tandem mass spectrometry(ESI-MS/MS) and the fragmentation pathways were investigated.

Figure 1. Peptide formation from conjugate of amino acid and nucleoside in anhydrous methanol.

Acknowledgements

References

Fox, S. W. and Dose, K.: 1977, Molecular Evolution and the Origin of Life, Marcel Dekker, New York. Gilbert, M.: 1986, Nature 319, 618. Herschlag, D. and Cech, T. R.: 1990, Nature 344, 405. Zhao, Y. F. and Cao, P. S.: 1994, J. Biolog. Phy 20, 283.

PHOSPHORUS PROMOTED PEPTIDE BOND FORMATION IN WATER WITHOUT COUPLING REAGENT Zhong-Zhou Chen, Xi Peng, Yan-Mei Li∗, Yu-Fen Zhao Bioorganic Phosphorus Chemistry Laboratory, Department of Chemistry, School of Life Sciences and Engineering, Tsinghua University, Beijing 100084, P. R. China

In many biological processes, phosphoryl participation was the key mechanism1. N-phosphoryl amino acids were proposed as models for the co-evolution of proteins and nucleic acids2, for they characterized biomimic reactivity, such as peptide formation, esterification and ester exchange on phosphorus. When the reactions of N-phosphoryl α-amino acids with other amino acids were carried out in aqueous media without any coupling reagents, two kinds of phosphoryl peptides were found. One was N-phosphoryl homo-dipeptide, formed by the self-assemble of phosphoryl amino acids. The other was N-phosphoryl hetero-dipeptide, formed by the cross-reaction of phosphoryl amino acids with amino acids (Figure 1). The phosphoryl hetero-dipeptide in the reaction mixtures were analyzed and identified by negative-ion and positive-ion electrospray mass spectrometry (ESIMS/MS). From the existence of characteristic fragmentations of ESIMS/MS mass peaks, such as a1,y1 and b1+H2O ion, the N-terminal amino acid residue of the phosphoryl hetero-dipeptides was identified from N-phosphoryl amino acid, not from the free amino acid (Figure 1). It has been proposed that N- phosphoryl amino acids could activate themselves through a phosphoric-carboxylic mixed anhydride (Figure 1)3−4. And the mechanism was supported by theoretical calculations. Therefore, the direction of peptide formation reactions from N- phosphoryl amino acids was from N-terminal to C-terminal, which was consistent with the peptide elongation direction in the biosynthesis of proteins. It might be useful in the study on the origin of protein, protein biosynthesis and combinational peptide synthesis.

Acknowledgements

We would like to thank the ﬁnancial supports from the Chinese National Natural Science Foundation (No. 29802006 and 20175026) and Tsinghua University. ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 431

Figure 1. The Peptide formation from N-phosporyl α-amino acids with other amino acids and the proposed mechanism.

References

Stock, J. B., Ninfa, A. J. and Stock, A. M.: 1989, Microbiol. Rev. 53, 450. Zhao, Y. F. and Cao, P. S.: 1994, J. Biolog. Phy. 20, 283. Chen, Z. Z., Tan, B., Li, Y. M. and Zhao, Y. F.: 2001, Int. J. Quan. Chem. 83, 41. Chen, Z. Z., Tan, B. and Li, Y. M. et al.: 2001, J. Mol. Struc.-Theochem 574, 163.

MOLECULAR INTERACTION OF N-PHOSPHORYL AMINO ACIDS Meijuan Fang, Yong Chen, Jianfeng Wang, Xiaoli Yang and Yufen Zhao∗ 1 School of Chemistry and Engineering, Xiamen University, Xiamen, 361005, P. R. China; Fax: 86-592-218-5780; Tel: 86-592-218-5780; e-mail: [email protected]; 2 The Key Laboratory for Bioorganic Phosphorus Chemistry, Ministry of Education, Department of Chemistry School of Life Sciences and Engineering, Tsinghua University, Beijing 100084, P. R. China

Molecules have a high tendency to form hydrogen bonds with solvent and other molecule. N-phosphoryl amino acids are chemically active species that exhibit biomimetic reactivity. It has also been proposed that N-phosphoryl amino acids are involved in the prebiotic synthesis of protein and nucleotides. In this paper it was found that amino acids can form adduct themselves or with each other and the ability of forming adduct is affected by pH, concentration and solvent by ESI- MS/MS. Furthermore, we observed that the ability of forming adduct was greatly strengthened after amino acids phosphorylated by ESI-MS/MS. Model studies (Fig- ure 1) indicated that the strengthening of binding ability may be due to the increasing of intermolecular hydrogen bonds from 1∼2to4ormore.IR,NMR,UV- VIS and APCI/ESI further conﬁrmed that the non-covalent complexes form in the solution. It is well known that biochemical reaction in vivo usually depends on non- covalent bonds between two molecules. Further work about the weak interaction of phosphoryl peptide, protein and nucleotide respectively will be outspreaded. In conclusion, the presence of phosphoryl group could promote the interaction of amino acids, peptides and proteins. This enhanced interaction mechanism might provide a clue to molecular evolution and functionalization of enzymes. 432 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

Figure 1. Model of adducts of N-phosphoryl Ala.

Acknowledgement

The authors would like to thank the ﬁnancial supports from the Chinese National Science Foundation (NO. 20175026), Fujian Key Foundation of Science and Tech- nology (2001F008) and Xiament University.

References

Smith, R.D., Bruce, J. E., Wu, Q. and Lei, Q. P.: 1997, Chem. Soc. Rev. 26, 191. Chen,Z.Z.,Chen,S.B.andChen,Y.et al.: 2002, Rapid Commun. Mass Spectrom. 16, 1–7. Wang, H. X. and Yang, S. C.: 2001, Acta Pharmaceutic Sinica 36(4): 315–320 (in Chinese). Lorenz, S. A., Maziarz, E. P. and Wood, T. D.: 2001, J. Am. Soc. Mass. Spectrom. 12, 795–804.

DIFFERENCE IN CLEAVAGE ACTIVITY OF CHIRAL DERIVATIVE OF DIPEPTIDE SERYL-HISTIDINE Hai Liu, Changjin Zhu, Jing Chen and Yu-Fen Zhao∗ Bioorganic Phosphorus Chemistry Laboratory, Department of Chemistry, School of Life Sciences and Engineering, Tsinghua University, Beijing 100084, P. R. China

Previously it has been found that the dipeptide seryl-histidine (Ser-His) and related oligopeptides can cleave DNA, protein, and the ester p-nitrophenyl acetate (p- NPA) over wide ranges of pH and temperature1. The hydroxyl functional group of Ser residues and the imidazole functional group of histidine were proved as the requisite groups for cleavages, while the carboxyl functional group of histidine has little effect on the cleavage activity. More studies on the chiral derivate of the dipeptide show some difference of the cleavage activities. This may help us to understand the chiral evolution of proteins and nucleic acids. ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 433

We synthesis some derivates of dipeptide seryl-histidine, showed as below (Fig- ure 1) and incubated them withλ-DNA. As revealed by agarose gel electrophoresis after 24 hours of incubation (Fig. 2), Linear bacteriophage λ-DNA at a ﬁnal concentration of 20 ng/mL, incubated with 5mM cleavage reagent in 100mM Britton- Robinson (BR) buffer (pH=6.4), was gradually degraded into smears of progress- ively smaller fragments of heterogeneous sizes and L-type cleavage reagent showed higher activities than D-type one. In contrast, DNA samples incubated under the same conditions without the cleavage reagents remained intact (Figure 2). This interesting phenomenon might be useful in the study on the chiral evolution of protein and co-evolution of life.

Figure 1. Molecular structures of derivatives of dipeptide serylhistidine: (a) L-type, (b) D-type.

Figure 2. Cleavage of λ-DNA. λ-DNA was incubated with cleavage reagents (+) or without cleavage ◦ reagents (–) in B-R buffer of pH 6.4 at 50 for 24 hours. All samples were subjected to electrophoresis in a 6%.

Acknowledgements

We would like to thank the ﬁnancial supports from the Chinese National Natural Science Foundation (No. 20175026 and 20132020) and Tsinghua University.

References

Li, Y. S, Zhao, Y. F. and, Hatﬁeld, S. et al.: 2000, Bioorg. and Med. Chem. 8, 2675. 434 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

INTERACTION BETWEEN N-(O,O-DIALKYL)PHOSPHORYL AMINO ACID AND MONOSACCHARIDES Zhao Liu, Lin Yu, Yang Lu and Yufen Zhao1,2∗ 1 School of Chemistry and Engineering, Xiamen University, Xiamen, 361005, P. R. China; Fax: 86-592-218-5780; Tel: 86-592-218-5780; e-mail: [email protected]; 2 The Key Laboratory for Bioorganic Phosphorus Chemistry, Ministry of Education, Department of Chemistry School of Life Sciences and Engineering, Tsinghua University, Beijing 100084, P. R. China

In our previous work, it was found that there were signiﬁcant differences of reactivity between hexoses and pentose when they reacted with pentacoordinate phosphorus compound. In this paper, we designed the reaction between N-(O, O-dialkyl)phosphoryl amino acid (DIPP-aa) and different monosaccharides such as D- ribose, D-glucose, etc. In experiment, excess monosaccharides were treated with N-phosphoryl alanine in different solvents and different pH. 31P-NMR was used to trace the reaction. Electrospray ionization mass spectrometry (ESI-MS) was used to analyze the products.

Figure 1. Stacked 31P-NMR spectra of DIPP-Alanine and Ribose.

It was found that in pyridine, D-ribose was reacted faster than D-glucose when treated with DIPP-Alanine as showed by 31P-NMR spectra. The stacked 31P-NMR spectra indicate that the products were carbohydrate phosphate (δ:-2.0∼3.0ppm) and pyrophosphate (δ: -10.0ppm) as also proved by ESI/MS analysis. More results will be presented in this paper.

Acknowledgement

References

Yu-Fen Zhao and Pei-Sheng Cao: 1994, Phosphoryl Amino acids: 1994, Common Origin for Nucleic Acids and Protein, Journal of Biological Physics 20, 283∼287. Ju, Y., Hu, J. J. and Yu-Fen Zhao: 2000, Reaction of Carbohydrates and Pentacoordinate Oxaphos- phorane and Their Biomimetic Mechanism, Phosphorus, Sulfur, Silicon Relat. Elem. Yu-Fen, Zhao, Hu, J. J. and Ju, Y.: 2000, Interaction between N-Phospho-amino acids and nucleoside in aqueous medium, Chin. Chem. Lett. 11(5), 407–408.

MOLECULAR MODELLING OF H-BOND INTERACTION BETWEEN DIPEPTIDE SERYL-HISTIDINE AND BUFFERS Ming Sun, Jing Chen, Ya-Ting Wang, Yuan Ma and Yu-Fen Zhao∗ Bioorganic Phosphorus Chemistry Laboratory, Department of Chemistry, School of Life Sciences and Engineering, Tsinghua University, Beijing 100084, P. R. China

With the hypotheses that the dipeptide Ser-His and related oligopeptides might work as the bio-mimics of serine proteinase, series of studies have been carried out in our laboratory. One of the most exciting results is that dipeptide Ser-His could cleave DNA and protein1. The hydroxyl functional group of Ser residues was proved as the requisite groups for cleavages and the imidazole functional group of histidine was proved can improve the cleavage activity. Taking Ser-His as the shortest bio-mimics of serine proteinase may help us to understand the evolution of proteins and nucleic acids. Another interesting phenomenon is that different buffers may have different inﬂuence on Ser-His cleavage ability. For example, both citric acid and Tris could inhibit the cleavage activity of Ser-His. We suppose that buffers may react with Ser-His and destroy the speciﬁc functional geometry of Ser-His. Molecular dynamic analyses were performed in order to understand the interaction between dipeptide Ser-His and buffers. It might be useful in the study on the origin of protein and co-evolution of life. Molecular modelling were performed with Sybyl version 6.7 on SGI O2 R10000 workstation. All simulations were carried out with Flexidock algorithm2. Results indicate that Ser-His is linked with buffer through some relatively strong H-bonds, which resulted in forming of Ser-His-Buffer complexes. Figure 1 shows the H-bond interaction between Ser-His and citric acid(a) and Tris(b), respectively.

Figure 1. Molecular structures of docked complex: (a) Ser-His---Citric acid, (b) Ser-His---Tris. 436 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

Acknowledgements

We would like to thank the ﬁnancial supports from the Chinese National Nat- ural Science Foundation (No. 39870415, 20175026 and 20132020) and Tsinghua University.

References

Li,Y.S,Zhao,Y.F.andHatﬁeld,S.et al.: 2000, Bioorg. and Med. Chem. 8, 2675. Sybyl, version 6.7: 2000, Tripos Associates: St. Louis, MO 63144.

STUDIES ON WEAK INTERACTION OF PHOSPHORUS COMPOUNDS AND AMINO ACIDS BY ELECTROSPRAY IONIZATION MASS-SPECTROMETRY Guo Tang, Lifeng Yang, Yong Chen, Hua Fang and Yu-Fen Zhao∗ 1 School of Chemistry and Engineering, Xiamen University, Xiamen, 361005, P. R. China. Tel/Fax: 86-592-2185780; e-mail: [email protected]; 2 The Key Laboratory for Bioorganic Phosphorus Chemistry, Ministry of Education, Tsinghua University, Beijing 100084, P. R. China.

As we all know, biochemical reaction in vivo usually depends on non-covalent bonds between two molecules, especially phosphorus compound. Weak interaction between molecules is important in biological system, such as DNA, enzyme and substrate, inter-recognition of antibody and antigene. With the development of bioanalytical technique, the gentleness, sensitivity, speediness, simplicity and accuracy, of the electrospray ionization mass allows to detect the adduct of interesting biological compounds. In this paper, we use ESI-MS and APCI-MS to investigate the weak interaction between N-diisopropyloxyphosphoryl acid (DIPPH) and different amino acids. There are some conclusions and further research work will be continued. 1. ESI-MS has higher ability to observe weak interaction of molecules than APCI. + We can see the peak of [(DIPPH)2-ALA] with ESI-MS, but it can not be seen with APCI. 2. The pH effects the intense of the peak of adducts obviously. Near pI(6.01) of Ala, the strongest peak was the adduct of DIPPH/α-Ala. When the pH was raised to 7.0, it disappeared, while the dimer peak of DIPPH/ DIPPH became stronger. The same phenomenon was observed on other L-amino acids. 3. Serine has the highest ability to form adducts with phosphorus compound. It is suggested that the phosphorus group is an important H-bond acceptor. The contribution of phosphorus compound to the interaction of amino acids (Protein constitution) might play an important role in origin and evolution of enzymes. ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 437

Figure 1.

Acknowledgement

We would like to thank the ﬁnancial supports from the Chinese National Sci- ence Foundation (No. 20132020), the Fujian Province Science Foundation (No. 2001F008) and Xiamen University.

References

Chen, Z. Z., Chen, S. B., Chen, Y., Li, Y. M., Chen, J. and Zhao, Y. F.: 2002, Rapid Comm. Mass 16, 1–7. Jj, G. J., Xue, C. B., Zeng, J. N., Li, L. P., Cai, W. G. and Zhao, Y. F: 1988, Synthesis 6, 444.

INHIBITION OF CITRIC ACID BUFFER SYSTEM ON CLEAVAGE ACTIV- ITY OF THE SMALLEST PEPTIDE Wang Ya-Ting, Zhao Yang and Zhao Yu-Fen Bioorganic Phosphorus Chemistry Laboratory, Department of Chemistry, School of Life Sciences and Engineering, Tsinghua University, Beijing 100084, P. R. China

Peptides play very important roles in biological activity and attract more attention on the research of its biological function [1–3]. Dipeptide is the smallest peptide. In our previous research work, it was found that serine-histidyl dipeptide (SH) is the smallest peptide that could cleave nucleic acids and proteins [4–6]. Cleavage activities of Serine-histidyl dipeptide (SH) on BSA and DNA are buffer dependent. Phosphate buffers promote the cleavage process, and citric acid (2-hydroxylpropane-1, 2, 3-tricarboxylic acid)-citrate buffer inhibits the cleavage. Citric acid could compete with BSA or DNA to form hydrogen bonds with SH, consequently, decreases the binding opportunity of SH with BSA and DNA, and further reduces the cleavage activity of SH. Bis-Tris could also bind with SH by hydrogen bond. It has inhibiting effect on cleavage of SH as well, but is less effective than citric acid. Theory calculation gives the value of free energy of the binding of SH with citric acid and Bis-Tris, it is proved that the combination of SH with citric acid is obviously stronger than that of SH with bis-tris. Therefore, citric acid is effective inhibitor for SH cleavage. 438 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

Acknowledgements

We would like to thank the ﬁnancial supports from the Chinese National Natural Science Foundation (No. 20132020) and Tsinghua University.

References

Chiosis, G. and Boneca, I.: 2001, Science 293, 1484–1487. Krishnan, V., Pham, W. and Messer, W. etc.: 1999, Bioorganic and Medicial Chemistry Letters 9, 3363–3368. Suetsuna, K.: 1998, J. Nutr. Biochem. 9, 415–419. LI, Y. F., Sha, Y. W., Ma, Y. and Zhao, Y. F.: 1995, Biochem. Biophys. Res. Commun. 213, 875–880. Li, Y. S., Zhao, Y. F., Hatﬁeld, S., Wan, R., Zhu, Q., Li, X. H., McMills, M., Ma, Y. and Li, J.: 2000, Bioorganic and Medicinal Chemistry 8, 2675–2680. Chen, J., Wan, R., Liu, H., Jiang, Y. Y. and Zhao, Y. F.: 2001, Chemical Journal of Chinese Universities 22(8), 1349–1351.

PHOSPHORUS OXYCHLORIDE DIRECTED PEPTIDE LIBRARY AND THEIR ESI-MS STUDIES Ning Zhou1,KuiLu2,YanLiu3,YiChen2, Guo Tang1, Shu-Xia Cao3, Ling-Bo Qu3 andYu-FenZhao1,2,3∗ 3 School of Chemistry and Engineering, Xiamen University, Xiamen, 361005, P. R. China; Fax: 86-592-218-5780; Tel: 86-592-218-5780; e-mail: [email protected]; 4 The Key Laboratory for Bioorganic Phosphorus Chemistry, Ministry of Education, Department of Chemistry School of Life Sciences and Engineering, Tsinghua University, Beijing 100084, P. R. China; 5 Department of Chem- istry, Zhengzhou University, Zhengzhou, 450052, P. R. China

Phosphorus and amino acids play important roles in life chemistry. There are many reports on peptides formation reactions related to the chemical evolution of life on the primitive earth. However, there is not much investigation on the intrinsic relationship between the phosphorus and amino acids. Our previous works have found that α-amino acids may occur many bioorganic reactions after being phosphorylated in H2O-alcohol media. Recently, we found that with the assistance of phosphorus oxychloride, α-amino acids could be phosphorylated by phosphorus oxychloride, then assembled into oligo-peptides, which were analyzed by electrospray ionization mass spectrometry (ESI-MS) and multistage electrospray ionization mass spectrometry (ESI-MS/MS). Quenching with water or various alcohols, the reaction mixtures yielded the corresponding peptides or peptides ester, respectively. As the reaction time was prolonged, the length of peptides increased. This paper reported a simple method to synthesize the homo-oligo-peptide-ester conjugated library by phosphorus oxychloride activation, and the result is helpful to comprehend further the relation between the phosphorus and amino acids, and give an inspiration for the study of the origin life. ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 439

Figure 1.

Acknowledgement

References

Zhao, Y. F., Ju, Y., Li, Y. M., Wang, Q., Yin, Y. W. and Tan B.: 1995, Int. J. peptide protein Res. 45, 514. Li, Y. M. and Zhao, Y. F.: 1993, Phosphorus, Sulfur and Silicon 78, 15. Fu, H., Li, Z. L., Zhao, Y. F. and Tu, G. Z.: 1999, J. Am. Chem. Soc. 121, 291. Zhou, N., Lu, K., Liu, Y. and Zhao, Y. F. et al.: 2002, Rapid Commun. Mass Spectrom. 16, 1–4. 440 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 441

CHIRALITY 442 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

HOMOCHIRAL SELECTION IN THE MONTMORILLONITE-CATALYZED PREBIOTIC SYNTHESIS OF RNA DIMERS P. C. Joshi1,S.Pitsch2 and J. P. Ferris1 1 Department of Chemistry and the N. Y. Center for Studies on the Origins of Life, Rensselaer Poly- technic Institute, Troy, N. Y. 12180; 2 Institut de Chimie Organique, Ecole Polytechnique Federale de Lausanne, EPFL – BCH, CH-1015 Lausanne, Switzerland

Prebiotic syntheses of the mononucleotide precursors of RNA are likely to have formed D, L-mixtures. We investigated the question whether these D, L-mixtures could have condensed to form homochiral RNAs. We studied the montmorillonite clay-catalyzed reaction of the 5’-phosphorimidazolides of D, L-adenosine (D, L- ImpA) and D, L-uridine (D, L-ImpU) to determine if clay mineral controls the course of the reaction (Joshi et al., 2001). The reactions of D, L-ImpA and D, L- ImpU on montmorillonite each produced oligomers with chain lengths that reached 7-9 mers. The structures of the linear and cyclic dimers formed were determined by selective enzymatic hydrolysis and the products were separated by liquid chromatography. The average ratio of D, D- and L, L- isomers to D, L-and L, D-isomers was about 75:25 for the dimeric products of A and about 90:10 for U. The uncata- lyzed dimerization of ImpA and ImpU produced 96:4 and 100:0 ratios of the D, D- and L, L-isomers to D, L and L, D-isomers, respectively although the overall dimer yields are considerably lower than the dimer yields formed in the clay-catalyzed reactions. These data show that catalysis preserves the natural tendency of these monomers to form homochiral reaction products. If this strong selectivity to form homochiral RNA also holds in the synthesis of the longer RNAs then there exists the possibility for the origin of two RNA worlds, one based on D-RNA and one based on L-RNA. If true, then the transformation to an exclusive D-RNA world would have been a subsequent evolutionary step.

References

Prakash C. Joshi, Stefan Pitsch and James P. Ferris: 2000, Chem. Commun. 2497–2498.

EXPERIMENTALPROCEDURES FOR MEASURING CHIRAL ASYMMET- RIES IN MAGNETIC FIELDS Vily Marius Cimpoiasu and Romulus Scorei University of Craiova, Biochemistry Department, A.I.Cuza13, 1100 Craiova, Romania

The concept of chirality is basically of geometric nature; therefore it is important to address it within its own dimensionality. In all chiral systems, there is a specific active property that allows chiral devices to interact. We believe that the origin of chiral interaction in molecular systems is to be found in the motion of free ions in aqueous solution. The amount and quality of water surrounding each solute ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 443 molecule is of crucial importance for free proton motion around the molecule. This protons motion, for example, is capable to stops and so does also, simultaneously, the enzymatic activity of the molecule. In order to observe chiral interaction through a direct experiment, it is necessary to observe the property generated by this effect. The physical rationale behind this experiment will lead to the natural selection rules for the D-enantiomer of sugar in terrestrial bio-molecular evolution. We start with the hypothesis that during the pre-biotic era an applied magnetic field (regarded as the component of terrestrial field) acted in the selection process of protons. To support this, we conducted studies on the dynamics of water protons in pure enantiomeric solutions of sugar, as well as in amino-acid solutions. Due to the fact that the magnetic field surrounding chiral molecules is not homogenous, the global motion of solute-water cluster is different from L and D solutions. This difference in motion can be analyzed using NMR pulse techniques, which enables to extract the differences in motion observed in the diffusion of water protons into a solute layer. In order to build a 3D geometric reference, a strong magnetic field Bo and circular polarized component of RF fields Bc (normal to Bo) were used. Thus, in magnetic fields, a small difference in energy is detected, due to the opposite orientation of induced magnetic moments related to Bo and Bc, between L and D solutions. We demonstrated that the combination of the diffusion coefficient, local gradient of the magnetic field on the solute layer and the interval of time between consecutive absorption pulses of circularly polarized RF field may be reduced to the distribution function of the magnetic susceptibility difference between pure water system and chiral solution. Taking as reference the evolution of the susceptibility distribution function in Bo field, we calculated the difference in energy between L and D solutions. This study shows that the distribution function of susceptibility difference in chiral solutions is correlated to two elements: one is the specific chemical function of the chiral compounds (example-OH), and the other one is the amount of water protons involved. Thus, we have estimated the difference in energy at EDL=0.5 10−33J. If we assume that the energy per molecule −17 is PEVD=10 kT, then we conclude that the accumulation EDL is generated by approximately 104-105 collision events, during the free evolution of the system in magnetic field. On the other side, the abundant water proton may be considered as an amplifier of the relative few bio-polymer protons. In this presentation we will describe these results, and discuss the mechanism of energy difference between enantiomers. Moreover, we will point out the role of the potential of terrestrial oriented magnetic field as an important physical condition for enantio-differentiation. 444 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

CHIRAL SELECTION IN THE GRADED AUTOCATALYIS REPLICATION DOMAIN (GARD) MODEL Doron Lancet, Daniel Segre, Barak Shenhav and Ran Kafri Dept. Molecular Genetics, Weizmann Institute, Rehovot, Israel

Graded Autocatalysis Replication Domain (GARD) is a model for prebiotic evolution (Segre et al., PNAS 97: 4112 (2000); Segre and Lancet, EMBO Reports 1: 217 (2000)). It entails mutually catalytic non-covalent molecular assemblies, typically consisting of lipid-like amphiphilic molecules. Stochastic chemistry simulations show that GARD manifests a metabolism-like network, as well as homeo- static growth and primitive self-reproduction. The information transferred from one generation to the next is in the form of a “compositional genome”. A significant attribute of the GARD model is its capacity to assume idiosyncratic internal assembly compositions (“composomes”), vastly different from those of the surrounding medium. We asked whether this property of GARD could also constitute an effective mechanism for chiral selection, a hallmark of life. For this, we developed the Chiral GARD (C-GARD) model, where each asymmetric molecule is represented by both the D and L optical isomers. The model is governed by Wigner’s law, which imposes symmetry properties on the matrix of catalytic rate-enhancements. It also includes an experimentally derived distribution of enantio-discrimination values. C-GARD computer simulations readily show symmetry-broken composomes, whereby many of the molecular components have significant enantiomeric excess. As expected, for every non-racemic composome, its compositional mirror image is equally likely. But at specific time points, one of the antipodal assemblies prevails. Under an exponential growth regimen stemming from the replication-like behavior, long-term domination of one of the antipodal assemblies is observed. Our study demonstrates that the generation of biological chirality may have not required pre-selection by external agents such as circularly polarized light, but could have stemmed naturally from the same processes which led to the emergence and evolution of the first molecular replicators.

ASYMMETRIC SYNTHESIS OF AMINO ACIDS BY Cr(II) COMPLEXES OF NATURAL AMINO ACIDS Gyula Pályi1, Orsolya Holzknecht2, Csongor Hajdú2, Milena Meo1,2, Claudia Zucchi1 and Károly Micskei2 1 Department of Chemistry, University of Modena and Reggio Emilia, Via Campi 183, I-41100 Mod- ena, Italy (e-mail: [email protected]); 2 Institute of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem-t. 1, H-4010 Debrecen, Hungary (e-mail: kmicskei@delﬁn.klte.hu)

The origin(s) of biological chirality [1] is deeply connected to the origin(s) of life itself [2]. Several, highly intellectual solutions of this problem were suggested, but experimental verifications of these hypotheses are rare [3], because of the lack of ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 445 suitable model systems. The reaction described in this paper, might be an initial stage of the development of such a model system. We found recently [4], that complexes of chromium (II) ions with chiral amino acids represent powerful reducing agents under “biomimetic” conditions and permit induction of chirality in new centers of (configurational) chirality. Now it has been found, that these Cr(II)/amino acid complexes can reduce (asymmetrically) C=N double bonds in amino acid-precursor oximes. Almost quant- itative conversions and enantiomeric excesses up to 30% were achieved. According to the best of our knowledge the present system is the first case, where ligand amino acid chirality is transferred to amino acid products obtained from prochiral precursors, opening thus the way for development of chiral autocatalysis [3d] induced by amino acids.

References

G. Pályi, C. Zucchi and L. Caglioti (eds.): 1999, Advances in BioChirality, Elsevier, Amsterdam, 1999. (ISBN: 0-08-043404-5). G. Pályi, C. Zucchi and L. Caglioti (eds.): 2002, Fundamentals of Life, Elsevier, Paris. (ISBN: 2- 84299-303-9). e.g. (a) A. Szabó-Nagy and L. Keszthelyi: 1999, PNAS 96, 4252–4255. (b) M. M. Green et al.: 1999, Angew. Chem. IE 38, 3139–3154. (c) G. Pályi et al.: 1996, Organometallics 15, 3253–3255. (d) K. Soai, T. Shibata and J. Sato: 2000, Acc. Chem. Res. 33, 382–390. (a) J. Gyarmati, C. Hajdú, Z. Dinya, K. Micskei, C. Zucchi and G. Pályi: 1999, J. Organomet. Chem. 586, 106–109. (b) G. Pályi, L. Bencze, K. Micskei and C. Zucchi: 2001, Atti Accad. Nazl. Sci., Lett. Arti (Modena), 317, [8/3], 457–477.

KINETIC MODELING OF THE HOMO- AND HETEROCHIRAL GHADIRI SELF-REPLICATOR Jesús Rivera Islas1, Jean-Claude Micheau2 and Thomas Buhse1 1 Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Morelos, Av. Univer- sidad No 1001, Col. Chamilpa, 62210 Cuernavaca, Morelos, México; 2 Laboratoire des IMRCP, UMR au CNRS No 5623, Université Paul Sabatier, 118, route de Narbonne, F-31062 Toulouse Cedex, France; e-mail: [email protected] (T. Buhse), [email protected] (J.C. Micheau)

Basic insight into the mechanism of self-replicating systems is essential to understand the origins of Life and offers now an apparently new view on the emergence of biomolecular homochirality. Prebiotically relevant self-replicators, showing per definition template-directed autocatalysis, were typically based on carbohydrate chemistry and referred to the RNA scenario of chemical evolution. More recently, an alternative self-replicator was developed by the Ghadiri group that was based on amino acids and that probably points towards a peptide directed scenario. This system also showed unexpected chiroselectivity in favor of the formation of homo- versus heterochiral peptides that opened the field to a possible explanation for 446 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 the enantiomeric purity of the biomolecules. We performed computational kinetic modeling of the Ghadiri system exploring its basic homochiral dynamics as well its heterochiral implications. For that purpose, a 6-step kinetic model for the homochiral case was designed that addresses the main reactions and hydrophobic interactions involved in this system and that showed excellent fitting of experimental data of four independent experimental series that were published. This model sheds light on the mechanistic principle of the reaction system and illus- trates directly several dynamic properties such as the direction of the net reaction fluxes and the reduced autocatalytic strength due to the interplay between con- stantly perturbed equilibria and irreversible reactions. For heterochiral conditions, “chiral combinatorics” have been additionally considered that render the model into a 66-step kinetic scheme of reversible and irreversible processes. Considering kinetic differences between homo- and heterochiral interactions among the peptide species, excellent fitting of experimental data was obtained. Due to simple re-distribution of chiral matter instead of its creation and because of enantiomer inhibition, net amplification of chirality is limited. Nevertheless, the Ghadiri system opens a highly valuable view on possible chiral inference in an alternative pre-biotic scenario.

CHARACTERIZATION OF ENZYME STEREOSPECIFICITY Akihiko Shimada Institute of Applied Biochemistry, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305- 8572, Japan

Recent studies have shown D-amino acids are widely distributed among organisms in contrary to expectation. Even the functional importance of D-alanine is demonstrated in dermorphin of waxy monkey frog. The broad distribution of D-amino acids in the present biological world shows organisms have been on intimate terms with D-amino acids since birth of life. It also suggests early organism might have been born in the state of racemic environment. If it is true, a special mechanism is required to select L-amino acids from racemic amino acids. Both the stereospecificity of enzyme and D-amino acid oxidase support chiral homogeneity in the present biological world. In early metabolism, D-amino acid oxidase was not useful because of anoxic environment. Thereby, the establishment of the stereospecificity is the prerequisite to built homochiral world. We know its significance to clarify the origin of homochirality, but don’t understand about its mechanism very much. This study describes its characterization. If the stereospecificity is labile, organisms will have difficulty in synthesizing highly pure chiral structures such as proteins. It will ultimately lead to the collapse of their world. So, we think it is too stiff to be modified. It, however, is not true very much. As a matter of fact, the stereospecificity is quite flexible. Tryptophanase that degrades L-tryptophan into indole, pyruvate and ammonia is an enzyme with strict stereospecificity. It is quite inactive to D type of tryptophan. When tryptophanase is in a highly concentrated triammonium ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 447 phosphate solution, its stereospecificity converts to react with D-tryptophan. This activity is dependent on reaction temperature. The activity on D-tryptophan is 0.5 % of that of L-Tryptophan at 37 ◦C, increasing with increasingly reaction temperature and 20 % at 55 ◦C. The activity on D-tryptophan increases forty times. On the other hand, the activity on L-tryptophan is very stable between 37 and 55 ◦Cinthe highly concentrated triammonium phosphate solution. This shows tryptophanase is not be denatured at all. Thus, the stereospecificity of enzyme changes in response to environmental changes.

1. ASYMMETRIC PHOTOLYSIS OF (DL)-ISOVALINE BY SYNCHROTRON RADIATION

Yoshinori Takano1, Takeo Kaneko1, Kensei Kobayashi1 and Jun-ichi Takahashi2 1 Department of Chemistry and Biotechnology, Yokohama National University, Hodogaya-ku, Yoko- hama, 240-8501 Japan (e-mail: [email protected]); 2 NTT Telecomunications Energy Laboratories, Atsugi, 243-0198, Japan

Since Pasteur discovered the asymmetry of life, many theoretical and experimental studies have been done to explain the origin of homochirality of biomolecules. Re- cent successful detection of enantiomeric excess in meteoritic L-form amino acids [1] implies the origin of biomolecular chirality came from exogenous influence; for example, specific circularly polarized light from neutron star radiation might result in asymmetric photosynthesis or photolysis. We examined possible asymmetric photolysis of amino acid by using circular polarized light from a synchrotron. Since remarkable enantiomeric excess (9.1 %) of isovaline (?-amino-?-methyl- butyric acid) was observed, we used isovaline as a target. An aqueous solution of (DL)-isovaline was subjected to photolysis with right (R-) and left (L-) circularly polarized light (CPL) obtained from Synchrotron Radiation (SR) at NTT’s SR facility. SR was proved to be beneficial tool to simulate synchrotron radiation from extraterrestrial bodies such as neutron stars. Though the target solution was neutral, R-CPL preferentially photolyzed D- isovaline, and L-CPL photolyzed more L-isovaline than D-isovaline: It was reported that usual amino acids such as leucine showed asymmetric photolysis only when the target solution was strongly acidic [2]. It is known that isovaline is one of non-?-hydrogen analogs of amino acids, which shows noticeable exception to the Clough-Lutz-Jirjensons rule. Such ?-methyl amino acids might conceivably have played a significant role in the chemical evolution and the origin of homochirality. We would like to express our greateful acknowledgement to Dr. J. R. Cronin and Dr. S. Pizzarello for offering norvaline and for helpful discussion. 448 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

References

J. R. Cronin and S. Pizzarello: 1977, Science 275, 951–955. H. Nishino et al.: 2001, Org. Lett. 3, 921-924. ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 449

POLYMERS 450 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

MAGNESIUM-DEPENDENT ASSEMBLY OF RNA BUILDING BLOCKS THROUGH LOOP-LOOP INTERACTIONS Kazuo Harada1, Satoru Horiya1,GotaKawai2, Ryota Saito3, Akira Katoh3 and Koh Kobayashi1 1 Department of Life Science, Tokyo Gakugei University, Koganei-shi, Tokyo 184-8501; 2 Depart- ment of Industrial Chemistry, Chiba Institute of Technology, Narashino, Chiba 275-8588; 3 Depart- ment of Applied Chemistry, Faculty of Engineering, Seikei University, Musashino, Tokyo 180-8633, Japan

Construction of DNA-based molecular assemblies by virtue of nucleic acid base- complementarity has received considerable interest because of their potential use in creating specific nanoscale topologies and in the construction of nanoscale molecular devices. On the other hand, RNA-based assemblies are attractive in that there are a variety of unique RNA-RNA interactions that may be utilized. The RNA loop-loop interaction is one such interaction that has been found in antisense RNA control, and in HIV RNA dimerization. RNA substrates for the formation of linear and cyclic assemblies were designed based on the dimerization initiation site (DIS) stem-loop of the human immunode- ficiency virus (HIV). The DIS contains a 6 nucleotide self-complementary loop sequence (GCGCGC), which anneals to form a “kissing” dimer in the presence of magnesium. We show that RNA loop-loop interactions can be used to construct specific linear and circular structures, and that the assembly and disassembly of RNA building blocks occurs in a magnesium-dependent manner as observed using polyacrylamide gel electrophoresis (PAGE) by comparing gels containing magnesium with those that do not contain magnesium, and by changes in CD absorption spectra. The ability to control the assembly of RNA building blocks using magnesium may be useful as a functional switch. In addition, naturally known loop-loop interactions often undergo structural isomerization to a more stable conformation, suggesting that structures of this kind may also act as a mechanical switch.

REGIOSELECTIVITY OF THREE-MERS FORMED IN THE MONTMORILLONITE-CATALYSED REACTION OF RNA DIMERS (pNpN) AND 5’-PHOSPHORIMIDAZOLIDES OF NUCLEOTIDES (ImpN) Eric Hebrard1,2 and James P. Ferris2 1 Magistère InterUniversitaire de Chimie, Dép. de Chimie, Ecole Normale Supérieure, 24 rue Lho- mond, F-75231 Paris Cedex 05, France; 2 New York Center for Studies on the Origins of Life, Dept. of Chemistry, Rensselaer Polytechnic Institute, Troy NY 12180, USA

Possible catalytic role of minerals in the formation of biomolecules on the primitive Earth was first proposed by Bernal (1949). It has then been postulated in the RNA world scenario that the condensation of activated RNA monomers could have been achieved by montmorillonite clay catalysis (Ferris and Ertem, 1993). Since then, some research has been focused on the primer elongation reactions that may have ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 451 occurred in the prebiotic route to longer RNA, and on the sequence- and regioselectivity of phosphodiester bond formation. Significant sequence- and regio-selectivity has been observed in the montmorillonite clay-catalyzed reaction of a mixture of the 5’-phosphorimidazolides of adenosine (ImpA), cytidine (ImpC), guanosine (ImpG) and uridine (ImpU), suggesting that a limited population of RNA dimers could have been formed in catalyzed prebiotic reactions, and not a random mixture of all possible structures (Ertem and Ferris, 2000). This study was extended from the formation of dimers to the formation of three-mers. The montmorillonite-catalyzed reaction of 5’-O-phosphoryladenylyl- 3’,5’-uridine (pA3’pU) and 5’-O-phosphorylguanylyl-3’,5’-uridine (pG3’pU) with a mixture of the 5’-phosphorimidazolides of A, U, G and C were performed and the three-mer fraction was isolated by anion-exchange HPLC. The structures of the reaction products were determined by selective enzymatic hydrolysis. These structural data were used to determine the regioselectivity of phosphodiester bond formation. These findings and those presented in the poster of S. Miyakawa and J.P. Ferris will be used to reach conclusions about the sequence- and regio-selectivity of phosphodiester bond formation in three-mers.

References

Bernal, J. D.: 1949, Proc. Physical Soc., Section A, 62, 537–558. Ferris, J. P. and Ertem, G.: 1993, J. Am. Chem. Soc. 115, 12270–12275. Ferris, J. P. and Ertem, G.: 2000, Origins Life Evol. Biosphere 30, 411–422.

ENZYMOLOGIST’S VIEW OF CLAY MINERAL CATALYSTS AS REL- EVANT TO PREBIOTIC OLIGOPEPTIDE SYNTHESIS Tadeusz Klopotowski and Galina Novik Instytut Biochemii i Bioﬁzyki PAN, Warsaw, Poland

Montmorillonite (MM), an anionic clay mineral is suggested to have been an important catalyst in prebiotic syntheses, including those of oligopeptides. We used MM and a cationic mineral, hydrotalcite for a study aimed at their interactions with amino acids. We have conﬁrmed earlier reports that MM, layered aluminum-silica minerals strongly bind basic amino acids. We also ﬁnd that they contain at least one other kind of sites – those for weak binding of amino acid ligands. Thus one site species provides negative charge for binding of three basic L- amino acids, the constituents of present day proteins and their D enantiomers – arginine, histidine and lysine. The strong interaction with any of the amino acids and competitive effects of imidazole indicate that positive charges of these ligands are involved in the sorption process with negatively charged active sites on MM. 452 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

The sites of another type allow sorption of any amino acid. The possibility is under study that zwitterionic van der Walls contour is involved. The data are plotted to get Freundlich, Hill and Scatchard isotherms providing a set of affinity parameters. There are some differences between certain of the weak MM sites in respect to amino acid specificity. It could mean that the specific orientation of the bound zwitterions would facilitate peptide formation. E.g. The basic amino acids would be preferentially bound to their sites and oriented upside down. This would favor peptide formation only between any of the three amino acids, but proper molecule positioning with any of the other amino acids and respective peptide formation would be less likely. Our data show that the predictions for hydrotalcite are similar except that the negatively charged amino acids, aspartic and glutamic, pair strongly whereas all others interact only due to their van der Waals contours.

THE FORMATION OF MINERAL PROTEINS Daniel Lowy, Matthew M. Lowy, Adam G.J. Lowy, Jonathan D. Lowy and Gordon Walker e-mail Addresses for correspondence: 20, Ormsby, Stanley Rd. Sutton Surrey, SM2 6TJ England; ‘TOUTOU’, Villespy, F-11170 Alzonne, France

Experimental studies of the interaction between clays and amino acids, here reviewed in sufficient detail to take account of the effect of parity violation, show that the process significantly selects between enantiomers. Of the solute that ad- sorbs to the clay, a substantial fraction consists of homochiral polypeptides, of which the two enantiomeric homologous series form independently. Irrespective of any topical enantiomorphism in the clay, each enantiomeric pair of homologues exists in chiral imbalance. The two series being of similar mass, when dissolved together for analysis their solution cannot but be approximately racemic, a result that experiments have confirmed, but from which the peremptory conclusion has been drawn that the interaction does not significantly select between enantiomers. However, observations from the same experiments are now seen to confirm that chiral discrimination – in this mode – had occurred in them. The present study shows that in each lower homologue the D- polypeptide pre- dominates, and in each higher homologue. the L- polypeptide. Since the L-series extends to a higher value of residue number than the D-, the highest polypeptides evidently arise as single L- enantiomers, completely free of their opposites. Pre- sumably, the range of peptide number of these ‘mineral proteins’ is at its greatest on those clays where adsorption is the strongest. ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 453

THE HCN WORLD: ESTABLISHING PROTEIN-NUCLEIC ACID LIFE Clifford N. Matthews Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois 60680, USA

Hydrogen cyanide polymers – heterogeneous solids ranging in color from yellow to orange to brown to black – could be major components of the dark matter observed on many bodies of the outer solar system, including asteroids, comets, moons and planets. They are readily hydrolyzed to yield peptides and alpha-amino acids, possibly derived from polyaminomalononitrile, a polyamidine structure built only from hydrogen cyanide. Also, hydrolysis/pyrolysis gives rise to nitrogen het- erocycles, including purines and pyrimidines found in nucleic acids today. Implications for prebiotic chemistry are profound. Primitive earth may have been covered by HCN polymers and other organic compounds through bolide bombardment or by photochemical reactions in a reducing atmosphere. Most signi- ﬁcant would have been the parallel synthesis of polypeptides and polynucleotides arising from the dehydrating action of polyamidines on nucleotides. On our dynamic planet, this polypeptide-polynucleotide symbiosis mediated by polyamidines may have set the pattern for the evolution of protein-nucleic acid systems contolled by enzymes, the mode characteristic of life on Earth today. Some recent experimental results consistent with this model for the original presence of an HCN World include the detection of: (a) large amounts of HCN in a massive protostar GL259 (Boonman et al., 2001), suggesting that HCN is crucial to starbirth; (b) tar-like polycyclic heteroaromatic molecules of H,C,N,O far beyond the orbit of Mars (Kissel et al, 2000) discovered by the Cometary and Interstellar Dust Analyzer of Mission Stardust on its way to rendezvous with Comet Wild in 2004 to collect and return to Earth cometary samples that may well consist largely of HCN polymers; (c) diketopiperazine following hydrolysis and thermolysis of HCN polymers (Minard et al., 2002) pointing to the presence of glycine oligomers formed directly from HCN and water; (d) long-lived organic free radicals (C,N and O-based) in HCN polymers, iden- tiﬁed through ESR studies (Liebman, Budil et al., 1999). These were also detected in a tholin consisting largely of HCN polymers. (e) possible presence of HCN polymers in the 3.5 billion year old Apex cherts of Warrawoona, Western Australia, and in the Murchison meteorite, based on laser- Raman spectra (Liebman and Matthews, 2002).

SOLID-STATE NMR SPECTROSCOPY STUDIES OF HCN POLYMER R. D. Minard, C. S. Gross. S. M. Mattingly and K. T. Mueller Penn State Astrobiology Research Center and Department of Chemistry, Penn State University, Uni- versity Park, PA, 16802 454 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

HCN polymer is of considerable interest due to its potential role in the origin of life. Solid-state NMR spectroscopy is a useful means by which to determine structural parameters of materials that are insoluble, thus lending itself well to the analysis of HCN polymer. Singly and doubly labeled 13C/15N hydrogen cyanide polymers of various enrichments were prepared. Detection of the total signal from the observed nuclei was determined by single pulse (SP) experiments. Cross-polarization (CP) spectra were obtained to determine those 13Cand15N bonded directly to a 1H. The difference between the SP spectrum and a CP spectrum indicated the relative number of 15Nor13C bonded to 1H to those that are not, as well as the various local environments of 15Nor13C that are bonded to 1H. Double cross-polarization (DCP) experiments were carried out via the transfer of polarization from 1H–15N – 13C(13C-DCP) and from 1H–13C–15N(15N-DCP). The difference between the DCP spectra and the 13C single CP spectra indicated the relative number of 13C bonded to 15N and those bonded to 14N, 12C, or 1H. Finally, DCP-REDOR NMR was used to reintroduce dipolar coupling information into a signal, providing internuclear distance information. Changes in these spectra occurring when HCN polymers were treated with water were also observed. The interpretation of these results in terms of the structure of HCN polymer and water-treated HCN polymer will be described.

PEPTIDE SYNTHESIS FROM AMINO ACID THIOESTERS AT MICEL- LAR INTERFACES Helmut H. Zepik Department of Chemistry and Biochemistry, University of California at Santa Cruz, Santa Cruz, CA 95064, USA

We have synthesized different amino acid thioesters with long-chain thiols. In aqueous buffer they self-assemble to form micelles. Amino acid polymerization is favoured compared to short-chain, water soluble thioesters due to approximation of activated amino acid headgroups. By this approach we have obtained peptides with > 20 residues. We will report on micelle structure and on the effects of reaction conditions on product length.

FORMATION OF POLYAMINO ACIDS IN MOLTEN UREA Hajime Mita, Masanori Terasaki, Shinya Nomoto, and Akira Shimoyama Dept. Chem., Univ. Tsukuba, 305-8571 Tsukuba, Japan

Ammonium salts or amides of maleic acid and their homologs have been known to afford polymers of aspartic acid or its homologies on heating in the solid state1. Ammonium salt of malic acid was also reported to afford aspartyl polymers by heating2. In this study, malic, maleic, and fumaric acids were heated individually in the presence of urea as a nitrogen source and polar reaction medium. ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 455

An equimolar mixture of urea and acid was placed in a degassed sealed glass test tube for 12 h at 140–200 ◦C. After heating, resulting polymer was hydrolyzed and amount of recovered aspartic acid was quantiﬁed by amino acid analyzer. The highest yield of aspartic acid determined after hydrolysis was observed in the reaction at 160 ◦C. The yields were a little lower in the reactions at 140 ◦Cthan 160 ◦C, while the yields largely decreasing in the reactions over 160 ◦C. Nearly half of aspartic acid was shown to be incorporated in polymer of molecular weight larger than 2,000. Furthermore, alanine was heating with urea and analyzed as same procedure as above. Polymer was obtained and its molecular weight ranged up to about 8,000. More than 90 % alanine was recovered in the hydrolyzate of fractionated polymer by ultraﬁltration (CMW: 8,000). These results showed the ability of molten urea as a good nitrogen source, polar medium and dehydrating reagent for formation of polyamino acids at chemical evolutionary stage.

References

Kokufuta, E. et al.: 1978, Bull. Chem Soc. Jpn. 51, 1555. Harada, K. and Fox, S.W.: 1975, Biosystems 7, 213.

A SIMPLE MODEL FOR THE PRODUCTION OF BIASED OLIGOPEPTIDES IN PREBIOTIC ENVIRONMENTS F. G. Mosqueira1, S. Ramos-Bernal2 and A. Negrón-Mendoza2 1 Dirección General de Divulgación de la Ciencia, UNAM. Cd. Universitaria, A.p. 70-487, 04510 México, D.F. México; 2 Instituto de Ciencias Nucleares, UNAM. Cd. Universitaria, A.p. 70-543, 04510 México, D.F. México

We consider that the minimal condition for the existence of a chemical machinery compatible with life should take into account a sort of biased conditions. In particular, when we analyze the polymerisation of monomeric units, it is important to assume differences among them. Such biased character would render a much smaller sequence space in comparison with a sequence space derived from a purely random polymerisation. In this work, we applied such ideas to the thermal oligomerization of amino acids. The electrostatics differences has been used as a main criteria of reactivity. With such basic knowledge we construct a simple model that considers an uneven probability of reaction among amino acids using the Markov chain formalism. The application of this model successfully predicts the experimentally ﬁnding of only two tyrosine-containing tripeptides, out of 36 expected, on the basis of a priori even probability of reaction among the participating amino acids (1). This 456 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 result is of importance because it reduces the sequence space to a certain degree. This is the difference effect. Another important feature of the model is related to the attainment to the steady state, which ﬁxes the population of oligomers, and in consequence constrains further the sequence space. This is the steady state effect). Both, the difference and the steady state effects, constrain the sequence space and may make more accessible the replication of a minimal set of oligomers {n} compatible with life.

References

Fox, S. W., Melius, P. and Nakashima, T.: 1977, ‘N-Terminal Pyroglutamyl Residues in Proteins and Thermal Peptides’, in H. Matsubara and T. Yamanaka T. (eds.), Proc. of the Symp. on Evolution of Protein Molecules, Japan Scientiﬁc Societies Press.

LOOKING FOR THE PRIMEVAL HONEYCOMB OF GENETIC MATER- IAL Claudio Vastano, Marco Franchi and Enzo Gallori DBAG – University of Florence – Florence, Italy

In recent years numerous observations have suggested that mineral surfaces could have played a key role in the prebiotic formation of biomolecules basic to life. Whereas the assembling of complex organic polymers by random collisions in a dilute aqueous environment seems rather improbable, mineral surface could have provided a suitable habitat for the adsorption and concentration of precursors, their polymerization (1) into larger molecules, and the preservation (2) of resulting polymers in critical conditions like those probably existing in the early Earth. Among the potential candidates as possible archean biochemical adsorbants, we have examined the attitude of four minerals: orthoclase, serpentine, and two clays, montmorillonite and kaolinite, to establish a close association with different nucleic acid molecules. In the present work the equilibrium adsorption, and biological activity of three nucleic acid molecules: chromosomal DNA, 16S rRNA and poly [A], adsorbed/ bound on the four minerals, are discussed in the light of their possible role in primeval habitats.

References

Ertem G. and Ferris J. P.: 1996, Nature 379, 238–240. Franchi M. et al.: 1999, Orig Life Evol Biosphere 29, 297–315. ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 457

ENZYMATIC ACTIVITY OF RNA ADSORBED ON CLAY MINERALS Marco Franchi and Enzo Gallori DBAG - University of Florence - Florence, Italy

It is widely accepted that autocatalytic cycles are important for the prebiotic origin of life, as they have contributed to the production of a rich chemical substrate on which natural selection has acted (1). The formation of ancestral autocatalytic self-replicating systems must have required not only the synthesis and accumulation of the first nucleic acid-like molecules, but also their mutual interaction. In particular, the first informative polymers had to be able to act both as genetic ‘stores’ and catalyzers of specific non- enzymatic reactions (ancestral ribozymes). The problem of the formation of such a system is still an unresolved question. Recently, observations on the synthesis of oligonucleotides on clay surface (2), and on the resistance of clay-adsorbed nucleic acids to environmental degradation (3) suggested that clay minerals could have played a key role in the formation and persistence of nucleic acid precursors. It is our belief that the formation of a close association between prebiotic genetic molecules and clay surfaces was a crucial step in the preservation of genetic information, allowing the genetic material to express its biological potential, i.e. to replicate and evolve. In the present work, the possible catalytic activity of an oligonucleotide containing the ‘hammerhead’ ribozyme sequence from LTSV viroid (4), both free and adsorbed on clay minerals montmorillonite and kaolinite, is discussed.

References

Eigen M.: 1992, Steps towards Life, Oxford University Press. Ertem G. and Ferris J. P.: 1996, Nature 379, 238–240. Franchi M. et al.: 1999, Orig. Life Evol. Biosphere 29, 297–315. Forster A. C. and Symons R. H.: 1987, Cell 49, 211–220. 458 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 459

RNA WORLD 460 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

PROGRESS IN THE SEARCH FOR THE MOLECULAR MIDWIFE Nicholas V. Hud1, Frank A. L. Anet2 and Matjaž Polak1 1 School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, 30332; 2 Department of Chemistry and Biochemistry, UCLA, Los Angeles, CA, 90095

We recently presented a detailed hypothesis for how a small planar molecule, the molecular midwife, could have facilitated the synthesis and replication of RNA- like polymers in the prebiotic world (Hud & Anet, J. theor. Biol. 205, 543-562 (2000)). The molecular midwife would have had two identical faces and the ability to intercalate the bases of RNA-like polymers. The central concept of our proposal is that the molecular midwife promoted base pairing between free bases, nucleosides, and existing RNA-like polymers by providing a hydrophobic surface with a size and shape very similar to that of (ApU)2 and (GpC)2 base tetrads. Based upon the structure of these tetrads, present candidates for the molecular midwife include derivatives and structural analogs of the organic dye molecule phthalocyanine. We have synthesized several water soluble aza-analogs of phthalocyanine and will discuss our initial investigations of their ability to organize mononucleotides. In a related study, we are investigating triple helix formation in the presence of nucleic acid intercalators that mimic the shape of (Py)p(Pu)p(Py) base triples. Results from these investigations support our proposal that small molecule intercalation is a powerful tool for driving nucleic acid assembly. These triplex studies have also provided us with insights for the design of our next generation small molecules to promote base tetrad formation.

CATALYTIC PARTNERS FOR RNA Meli Marc and Maurel Marie-Christine Institut Jacques Monod, Tour 43, 2 place Jussieu, F-75251 Paris cedex 5, France

The RNA world hypothesis assumes that modern life arose from a molecular ancestor in which RNA molecules both stored genetic information and catalyzed biochemical reactions (1). If an RNA world really existed in the past, RNA world ribozymes must have been able to widen their catalytic repertoire to fuel an early metabolism. Primeval nucleotides were not necessarily limited to standard nucleotides as we know them today (2). We put forward the hypothesis that catalytic building blocks carrying imidazole (3), thiol, amino, carboxylate groups etc. could have been incorporated into early RNA ribozymes. Another way for RNAs lacking such reactive chemical groups is to handle small molecules to use them as a cofactors. We have already selected RNA aptamers for adenine showing a novel mode of purine recognition, in order to design ribozyme aptamers using extrinsic adenine as cofactor (4). We have undertaken a new SELEX procedure where the selection scheme is designed to yield cofactor-assisted self cleaving RNA aptamers. Such cofactor assisted ribozymes could thus model remnants RNA world ribozymes handling exogenous small prebiotic reactive ligands as cofactors. ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 461

References

Joyce, G. F. and Orgel, L. E.: 1993, The RNA World, in Gesteland, R. F., Cech, T. R. and Atkins, J. F. (eds). Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY. Maurel, M-C.: 1992, J. Evol. Biol. 2, 173–188. Maurel, M-C. and Ninio, J.: 1987, Biochimie 69, 551–553. Meli, M., Vergne, J., Décout, J.L. and Maurel, M-C.: 2002, J. Biol Chem. 277, 2104–2111.

BRIDGING THE RNA- AND PROTEIN WORLDS: A POSSIBLE ROLE OF NUCLEOTIDE-LIKE COENZYMES Mikhail S. Kritsky A.N. Bach Institute of Biochemistry RAS, Leninsky Prospekt 33, Moscow, 119071, Russia, e-mail:

To bridge the co-evolution of nucleic and protein worlds a novel approach, other than a search of the roots of genetic coding, is proved. This approach proceeds from a fact, that pyridine, pteridine and isoalloxasine coenzyme molecules combine a structural similarity to the RNA monomers and dimers with the remarkable photochemical activity. Coenzymes itself are known to be rather poor catalysts, and there was a binding to appropriate apoproteins that has given rise to active enzymes. Another way these molecules could achieve a higher catalytic activity is to undergo photoexcitation. Excited flavin and pterin coenzymes are efficient light harvesters and photocatalysts, i.e. energy can migrate from their excited molecules to another substance or it can drive electron and group transfer. Such photoreac- tions, a possible rudiment of primitive photobiology, are widespread in modern organisms. It is presumed that within the RNA world oligonucleotide-bound coenzyme molecules existed, and the photochemical activity of such chimeras could substantially expand a catalytic power of RNA world. Since NAD and FAD are not discriminated from nucleoside phosphate substrates in priming of the enzymatic template-directed RNA synthesis, the presence of such chimeras even in modern organisms is not forbidden. The transition from RNA world to a practically full assignment of the genetic information storage and a catalysis to a distinct polymer type had to eliminate coenzymes from genetic material because of a lesser structural fitness in base pairing and to promote those primitive RNA-directed polypeptides, which catalytic effectiveness had increased after coenzyme binding. Supported by Russian Foundation for Basic Research Grant 01-04-48268. 462 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 463

GENETIC CODE 464 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

THE SELF-REFERENTIAL GENETIC CODE Romeu C. Guimaraes Dept Biologia Geral, ICB, Univ Federal Minas Gerais, 31270901 Belo Horizonte Brazil; Fax +5531- 34992570, e-mail: [email protected]

Evidence that the genetic code is organized in tRNA pairs was first presented to ISSOL’96. tRNA pairs are formed with conservation of principal dinucleotides (pDiN; 5’ central → 3’ base; homogeneous, Ho, RR:YY; mixed, Mx, RY:YR), varying the wobble position. Sequential addition of pDiN pairs follows from Ho to Mx pDiN and synthetases class 2 (RS2) to RS1, intermediate pairs containing both classes. Expansions of LeuRS1 to AA and of ArgRS1 to CU boxes formed the hexacodonic attributions. Stages: 1 Ho; central G, C; RS2- CC:GG (Gly:Pro); GA:CU (both Ser). 2 Ho; central A, U- UC:AG (AspRS2 plus the RS1 couple Glu:Leu); UU:AA (As- nRS2 plus the peculiar RS2 couple Lys [RS1 in some organisms]:Phe [acylating at 2’, like all RS1). 3 Mx; 3’ G, C- GC:CG (AlaRS2:ArgRS1); UG:AC (HisRS2 plus the RS1 couple Gln:Val). 4 Mx; 3’ A, U- GU:CA (ThrRS2: the RS1 couple Cys, Trp); AU:UA (RS1; Ile, Met:Tyr). Mechanism: when a charging system was fixed, its tRNA would be in conflict in pairing either with its complementary tRNA or codon. The solution was fixing a next attribution to the conflictive tRNA, efficiently removed by the peptidyl- transferase sink. The model is consistent with early coding by poly-tRNAs (Bloch, McArthur, Widdowson, Spector, Guimaraes, Smith 1984 tRNA-rRNA sequence homologies: a model for generation of a common ancestral molecule and prospects for its reconstruction. Orig. Life Evol. Biosph. 14:571-8), building a self-referential system. The process stopped when all tRNA pairs received attributions. The system then became able to accept any mRNA sequences, conflicts becoming regulatory. (FAPEMIG, CNPq)

THE FUNCTIONAL GENETIC CODE Romeu C. Guimaraes, Carlos HC Moreira∗ and Rafael C Melo Dept. Biologia Geral, ICB, Univ Federal Minas Gerais, 31270901 Belo Horizonte Brazil; ∗Dept Matematica, ICEx

Participants in the genetic code acquired meaning when the system became autocatalytic, synthetase proteins being builders and products, tRNAs and amino acids substrates (RCG 2002 (in press) An evolutionary deﬁnition of life: from metabolism to the genetic code. In: G Palyi, C Zucchi, L Caglioti eds., Fundamentals of life, Elsevier, Paris). ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 465

tRNA and synthetase pairs were examined in the accompanying communica- tion, protein and amino acid residue properties shown here. Details, albeit incom- plete, are in press (RCG, CHCM Genetic code structure and evolution: aminoacyl- tRNA synthetase classes and principal dinucleotides. Fundamentals of life). Stages 1, 2. Hydropathy outliers and the most conspicuous RNA-binding amino acid residues started the code (1), hydropathy correlation being established in 2. All amino acids precursors to biosynthetic families and characteristic of coils and turns of proteins belong in 1, 2. The protein-ends rules were established (RCG 2001 Two punctuation systems in the genetic code. 91-4 In: J Chela-Flores, T Owen, F Raulin eds., First steps in the origin of life in the universe, Kluwer, Dordrecht). 3. Seven of the eight amino acids characteristic of helices were accumulated. 4. The six amino acids were biosynthetically derived, adding ﬁve of the seven characteristic of strands of proteins plus speciﬁc punctuation. The single amino acid placed non-consistently with biosynthesis routes might be due to early occupation the CC:GG pair with Gly, the GG box being later substituted by Pro. (FAPEMIG, CNPq)

PRIMITIVE MOLECULAR MACHINES AND THEIR RELEVANCE TO THE STRUCTURE OF THE GENETIC CODE Gustavo Martinez-Mekler1, Maximino Aldana2, Germinal Cocho3 and Hernan Lar- ralde1 1 Centro de Ciencias Fisicas, UNAM, Apdo. Postal 48-3, Cuernavaca, Morelos, Mexico; 2 James Frank Institute,University of Chicago, 5640 South Ellis Avenue, Chicago , Il 60637, US; 3 Instituto de Fisica, UNAM, Apdo Postal 20-364, 01000 Mexico DF, Mexico

We address the question of why there are three bases per codon. We approach this problem from a dynamical point of view by considering the translocation properties of primitive molecular machines operating under prebiotic conditions [1,2,3,4]. Our model captures some basic ribosome-mRNA interaction features. We consider short chains of charged particles interacting with polymers via elec- trostatic forces, constrained to move in quasi one-dimensional geometries, subject to external forcing. Our numerical and analytic studies of statistical properties of the chain-polymer random interactions suggest that under very general conditions, a dynamics is attained in which the chain moves along the polymer in steps of three monomers. This behavior is enhanced when we consider present day protein coding sequences. We also comment on noncoding sequences. We argue that this property could be one of the underlying causes of the three base codon structure of the genetic code. 466 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

References

G. Martínez-Mekler, M. Aldana, F. Cázarez-Bush, R. García-Pelayo and G. Cocho: 1999, Primitive Molecular Machine Scenario for the Origin of the Three Base Codon Composition, Origin of Life and Evolution of the Biosphere 29, 203–214. M. Aldana, F. Cázarez-Bush, G. Cocho and G. Martínez-Mekler: 1998, Primordial Synthesis Machines and the Origin of the Genetic Code, Physica A. 257, 119–127. G. Martínez-Mekler, M. Aldana and G. Cocho: 1999, ‘On the Role of Molecular Machines in Origin of the Genetic Code in Statistical Mechanics of Biocomplexity’, in D. Reguera, J. M. G. Vilar and J. M. Rubi (eds)., Lecture Notes in Physics 527, 112–123 (Springer-Verlag, Berlin). M. Aldana, G. Cocho, H. Larralde and G. Martinez-Mekler, Translocation Properties of Primitive Molecular Machines and Their Relevance to the Structure of the Genetic Code, Journal of Theoretical Biology (in press).

EPIGENETIC SILENCING MAY AID EVOLUTION BY GENE DUPLICA- TION Dedicated to the memory of Susumu Ohno Sergei N. Rodin* and Arthur D. Riggs Beckman Research Institute of the City of Hope, 1500 East Duarte Road, Duarte, CA 91010-3000; ∗ To whom correspondence should be addressed, e-mail: [email protected], Phone: (626)-359-8111 (ext. 62381), Fax: (626)-357-1929

Gene duplication is commonly regarded as the main evolutionary path towards the increase of biological complexity in general and gain of new genes in particular. However, present population genetic theory indicates that most newly born duplicates should degrade to pseudogenes simply because null mutations are much more frequent than advantageous mutations. Thus, even with gene duplication, there is a loss vs. gain dilemma; and some additional impetus seems to be needed in order to shift the loss vs. gain equilibrium towards the functional divergence. We approached the dilemma from two perspectives. First, we have extended present mathematical models, which are based on the assumption that just-duplicated genes have exactly the same expression pattern, to the case when these duplicates may be epigenetically silenced at different developmental stages and/or in different tissues. Also, equations are derived from a model for evolutionarily reversible epigenetic silencing when a duplicate is “sleeping” for many generations and occasionally “awakens”. Our analyses indicate that both these types of epigenetic silencing can strongly protect duplicates from “pseudogenization”, thus enhancing evolution to new function. Importantly, however, this is true only in species with a small effective population size, Ne, as is the case for mammals and other higher organisms, and only when, tRS «4Ne,wheretRS is the average time between silencing and awakening. A second perspective of our study became apparent when we noticed in a previous publication [Lynch, M. & Conery, J.S. (2000) The evolutionary fate and consequences of duplicate genes. Science 291, 1151–1155] that the frequency of functional young gene duplicates is higher in organisms that have cytosine ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 467 methylation (H. sapiens, M. musculus and A. thaliana)thaninorganismsthat do not have methylated genomes (S. cerevisiae, D. melanogaster and C. elegans). Our genome-wide data analysis of the relative expansion of multigene families in different species confirms the likelihood of more efficient functional divergence of gene duplicates in mammalian and plant genomes than in nematode and fly genomes. Finally, based on the genome-wide comparisons of relative expansion of gene families in different pro- and eukaryotes, we address the problem of the genetic code origin (on Earth, within the solar system or beyond) and its evolutionary age by backward extrapolating the proteome size data. 468 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 469

PRE-CELLULAR SYSTEMS 470 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

ORIGINS OF NITROGEN FIXATION – THE IMPORTANCE OF MOLYB- DENUM AND PTERIDINES Bettina Heinz Palomar College, 1140 W. Mission Road, San Marcos, CA 92069, California State University San Marcos, Twin Oaks Valley Road, San Marcos, CA 92069

Pteridines have been produced by thermolysis and pyrolysis of dry amino acid mixtures (Heinz et. al) as a possible prebiotic pathway. Molybdenum is the only second row transition metal of bioactive importance. It is abundant and widespread, biologically represented by the molybdoenzymes in Eubacteria, Archae, and Eukarya. With exception to the nitrogenase enzymes, all depend on the molybdopterin cofactor that has remained unchanged since life began. However, all molybdenum containg enzymes are associated with various arrays of iron-sulfur clusters. Pter- idines are involved in all the Oxomolybdoenzymes that transfer atomic oxygen through redox processes. Nitrogenase, that requires molybdenum (or vanadium) but not pterins is found in certain anaerobic bacteria and cyanobacteria. So far, no other protein is known to be involved in making atmospheric nitrogen available for living systems. This also indicates the essential role of molybdenum and its association with Fe-S cluster containing proteins for the origins of life. Since pteridines are involved in all other MoFeS-enzymes, it could be that it has a cryptic signiﬁcance in nitrogen ﬁxation as well. Pteridines by virtue of their multi redox potentials, which can even be compared to certain transition metals, might play a transient role as an extra ligand to molybdenum, that is known to be able to expand to seven coordination sites. Thermophilic anaerobes utilize tungsten in the same cofactor complex.

SELF-ASSEMBLED VESICLES OF MONOCARBOXYLIC ACIDS AND AL- COHOLS: ENVIRONMENTAL CONDITIONS FOR STABILITY AND FOR THE ENCAPSULATION OF FUNCTIONING BIOPOLYMERS Charles L. Apel 1∗, Pierre-Alain Monnard1, Michael N. Mautner2,3 and David W. Deamer 1 1 Department of Chemistry and Biochemistry, University of California, Santa Cruz USA; 2 Soil, Plant and Ecological Sciences Division, Lincoln University, Canterbury, New Zealand; 3 Department of Chemistry, University of Canterbury, Christchurch, New Zealand; ∗ Corresponding author, Fax: +1- 831-459-2935, e-mail address: [email protected]

Monocarboxylic acids have been identified as the surface-active components in carbonaceous meteorites, and are also formed in simulations of hydrothermal vents. Their presence on the early Earth suggests they could have played a major role in the formation of protocellular membranes. We tested the ability of these compounds to form bilayer membrane vesicles and determined under what conditions these structures would be stable. Minimum concentrations and pH ranges were measured for each chain length between 8 and 12 carbons. Bilayer vesicles of ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 471 carboxylic acid formed near the pKa of the carboxylate head group. The addition of small amounts of alcohol of the same chain length markedly stabilized the bilayers, and vesicles were present at significantly lower concentrations than with the acids alone. These vesicles provided a selective permeability barrier as indicated by osmotic activity and ionic dye capture and were able to sequester macromolecules such as DNA and proteins. Encapsulated catalase was protected from degradation by protease and could act on its substrate, hydrogen peroxide, which readily diffused across the barrier. Monocarboxylic acid vesicles were destabilized by high concentrations of NaCl and divalent cations such as Mg2+,andCa2+.Ad- ded amphiphiles such as alcohols and glycerol monodecanoate partially mitigate this effect. We conclude that mixtures of amphiphilic molecules were plausible components of primitive membranes providing relative stability to the effects of ionic solutes, and sufficient permeability to nutrients from the environment.

PRIMITIVE PHOTOPHOSPHORYLATION IN FLAVOPROTEINOID MI- CROSPHERES IN PRESENCE OF MOLECULAR OXYGEN AND SUPER- OXIDE ANION RADICAL Michael P. Kolesnikov and Mikhail S. Kritsky A.N. Bach Institute of Biochemistry, Russian Academy of Sciences, Moscow, Russia; e-mail

The photochemical ADP to ATP phosphorylation with participation of flavopro- teinoids (FP) and flavoproteinoid microspheres (FPM) was studied to mimick primitive process of solar energy accumulation. FP was prepared by a 6 hr heating (185circC) of dry mixture of glu, gly and lys (8:3:1), the ratio found to be optimal for the flavin-like (isoalloxasine) compounds synthesis. The FPM were obtained after the well-known method of S.W. Fox with our modification. Since, according to our data, incorporation of silicon-containing compounds elevated the stability of aqueous FPM-suspensions, the boiling FP-solution was supplemented with 5 −1 5 mg·ml of Si(OH)4 monomer. Irradiation with blue light (300–500 nm, 1.5×10 −1 erg·cm·s ) under aerobic condition of a mixture containing ADP, K2HPO4, FPM- suspension and Na2-EDTA led to ATP accumulation demonstrated by luciferin- luciferase method and to the formation of O2¯ anion radical revealed by cytochrome c reduction test. After 90 min irradiation the ATP content reached 58.5 nmol·ml−1 (pH 8.6) and 94.5 nmol·ml−1 (pH 9.6) against 5.7 nmol·ml−1 and, respectively, 8.2 nmol·ml−1 in the dark. Since anaerobic condition as well as the addition of erythrocuprein (Cu-containing protein with SOD activity blocking O2¯ accumulation) inhibited the ATP synthesis, we believe that oxygen, likely the O2¯ radical, is involved in the flavoproteinoid-mediated ADP to ATP photophosphorylation. Supported by Russian Foundation for Basic Research Grant 01-04-48268. 472 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

CHEMICAL EVOLUTION IN THUNDER CLOUDS Victor A. Gusev Sobolev Institute for Mathematics of Siberia Division Russian Academy of Science, Novosibirsk, Russia. Phone: 3832-331979, fax: 3832-332598, e-mail: [email protected]

The paper presents hypothesis about of the principal new source of free energy for synthesis of organic molecules from non-organic oxides and other water-soluble molecules. The media, in which the chemical synthesis may be realized is water drop by ﬂying in the thunder clouds of primitive Earth’s atmosphere or another planets. The spherical symmetry of a drop, availability of the liquid-gas boundary and the permanent non-equilibrium steady state of water medium are organizing and ordering factors. According to my calculations the water drop of micron size represents a proto- type of a microorganism cell: on the inside of hydrophobic cover exists solution of organic molecules of physiological concentration. Moreover, volume of this compartment contained small polymers, among of these can be oligo-peptides and oligo-nucleotides of D and L chirality. The total time of the chemical evolution in the drop is about one second. “Soft” source of the energy is essential point of this model.

References

1. Gusev, V.A. The Electromagnetic Background of the Planets and their Biota. The newsletter of IS- SOL the international society for the study of the origin of life. Spring 2001. Vol. 28, Nos. 1 & 2. Gusev, V.A. The source of energy for survival and multiplication of heterotroph microorganisms in the absence of organic substratum. Biophysics (Rus.), 2001. V. 46, N 5, P. 862–878. Gusev, V.A. The chemical evolution into thunderous clouds. Dokl. RAN (Rus.), 2002, in press.

SELF-MAINTAINING MINIMAL CELLULAR SYSTEM: A KINETIC ANA- LYSIS Félix Olasagasti1, Álvaro Moreno2, Juli G. Peretó3 and Federico Morán1 1 Dpto. de Bioquímica y Biología Molecular I, Facultad de CC. Químicas, Universidad Complutense de Madrid; 2 Dpto. de Lógica y Filosofía de la Ciencia, Universidad del País Vasco UPV/EHU, Donostia/San Sebastián; 3Dpt. de Bioquímica i Biologia Molecular, Facultat de Ciències Biolò- giques, Universitat de València

Multiple approaches have been developed in the modelling of protocells, their formation being the key stage in the origin of life. They would be the bridge between purely chemical self-organizing systems and properly biological systems. Most of the models do not consider metabolic aspects but emphasize the replicating capability. These models assume that the prebiotic system works powered by some source of molecular energy currencies whereas very little description is given of the processes that protocells should use to generate that fuel-molecules and maintain ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 473 themselves. The main contribution of the model presented here consists on the combination of both a kinetic and energetic description of the metabolism. These aspects are necessary for the basic autonomy of the systems that will later form living systems, but they were rarely considered in previous works. In this model the role of the membrane is not a merely passive structural one but it has a very crucial role in the mantainance of the cell and its osmotic stability. In addition, the problem of the osmotic crisis (i.e. osmolysis) is addressed. In order to include all these considerations the model contains the following elements: structural membrane elements (L), transducers (T), molecules which combine enzyme-like activity with the transport of ions through the membrane (E), energy currency molecules (A), precursors of each type of molecule (l,t,e and a, respectively) and ionic substances (x). Different sets of kinetic parameters for all the elements in the system lead to a stable steady state, as studied through numerical analysis. The role of the external restriction and energy source in the size and relative distribution of the system elements is also presented. Other properties such as cell growth and division as well as inclusion of information mechanisms will be a matter of future work. 474 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 475

HYDROTHERMAL SYSTEMS 476 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

ABIOTIC FORMATION OF LINEAR HYDROCARBONS IN ULTRAMAFIC ROCKS OF THE OCEAN FLOOR Nils G. Holm Department of Geology and Geochemistry, Stockholm University, SE-106 91 Stockholm, Sweden, e-mail: [email protected]

Abiotic organic synthesis in ultramafic peridotite rock of the ocean floor has several implications for our view of the origin of life on Earth. Water in contact with the peridotite is reduced to molecular hydrogen with the concomitant oxidation of Fe(II). The molecular hydrogen formed may at high temperatures be combined with CO2 or CO for the abiotic formation of organic compounds such as hydrocarbons and fatty acids through Fischer–Tropsch Type (FTT) synthesis. Thus far the ultramafic rocks provide the most potent environments for the initiation of chemical evolution eventually leading to Darwinian evolution. The chemistry of FTT reactions is likely to promote the concentration and isolation of metabolic systems into separate entities. In contemporary cell membrane lipids, hydrophobicity is provided by hydrocarbon chains of fatty acids with chain lengths ranging from 12 to 20 or more carbons. Linear hydrocarbons with lengths ranging from 16 to 29 carbons have now been isolated in fluids of peridotite-hosted hydrothermal systems of the Mid-Atlantic Ridge. It has previously been difficult to identify plausible sources of long linear carbons chains in the prebiotic environment on Earth. Such chain lengths are relatively abundant in carbonaceous chondrites and it has been hypothesized that amphiphilic substances on Earth may have derived from meteoritic infall. However, the discovery of reactions in hydrothermal systems associated with ultramafic rocks on Earth provides an alternative pathway for the formation of early membranes and the first compartmentalization of life’s constituents.

SCREENING A NEW COLLECTION OF DEEP-SEA VENTS THERMO- COCCALES FOR PLASMIDS AND VIRUSES Marguet, E., LePage, E.,∗, Soler, N., Myllykallio, H., Zillig, W., Taillez, P.,∗ and Forterre, P. ∗ Institut de Génétique et Microbiologie, Bat 409, UPS, F-91405 Orsay, Cedex, France; Unité de Recherches Laitières et Génétique Appliquée, Domaine de Vilvert, F-78352 Jouy-en-Josas cedex – France

Viruses are the major component of biodiversity and they have most likely played a critical role in early life evolution (1, 2). However, the number of viruses presently described is still extremely limited, especially in the third domain of life: the Archaea. Several new virus families have been described that infect thermophilic aerobes of the genus Sulfolobus (3), but nothing is known about virus infecting hyperthermophilic anaerobes of the euryarchaeal kingdom. We have started a search for such viruses in hyperthermophiles of the order Thermococcales. We are also interested to study viruses and plasmids from these micro-organisms in order to ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 477 developp genetic tools for hyperthermophiic Archaea.We have isolated on plates 70 new Thermococcales from hydrothermal deep-sea Vents. RAPD of all isolates, 16S rRNA sequencing of RAPD selected groups representatives, and comparison with all Thermococcale type strains, suggest that this collection includes one new Pyrococcus species and about ten new Thermococcus species. We have screened systematically all isolates for extrachromosomal elements (plasmids and/or viruses) by restriction analysis of total DNA, puriﬁcation of ‘plasmidic’ DNA, and electron microscopy. About one third of all isolates harbor putative extrachromosomal elements. One strain of Thermococcus (30-1), contain two distinct extrachromosomal elements (one of 4 kb, the other of about 24 kb), which are induced in stationary phase, followed by cell lysis. Virus-like particles can be detected by EM in Thermococcus 30-1 cultures. Cloning of these two extra-chromosomal elements is underway.

References

Forterre, P.: 1999, Displacement of cellular proteins by functional analogues from plasmids or viruses could explain puzzling phylogenies of many DNA informational proteins, Mol. Microbiol. 33, 457–465. Forterre, P.: 2001, New viruses for the new millenium, Trends Microbiol 9. Zillig, W. et al., 1998, Genetic elements in the extremely thermophilic archaeon, Sulfolobus Extremophiles 2, 131–140.

FORMATION AND OLIGOMERIZATION OF AMINO ACIDS IN A SU- PERCRITICAL WATER FLOW REACTOR SIMULATING SUBMARINE HYDROTHERMAL SYSTEMS Md. Nazrul Islam, Masahiro Murata, Takeo Kaneko and Kensei Kobayashi Department of Chemistry and Biotechnology, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan, e-mail: [email protected]

Discovery of submarine hydrothermal systems (SHSs) in the late 1970’s has given us the new idea to think about the “local reducing” condition for the abiotic synthesis of organic compounds as well as for the chemical evolution and the origin of life. Several theoretical and experimental studies have been performed for the simulation of SHSs. Both of the cases reactions were being done in the closed tube. Whereas, SHSs are considered to be flow reaction systems and temperature of the reaction zone is near 350˚C, and there are may be some points consisting of supercritical conditions of water. So, we constructed a novel supercritical water flow reactor (SCWFR) to simulate SHSs. A novel SCWFR was constructed and were performed some experiments. In our study a mixture of KCN (0.1M), HCHO (0.1M) and NH4HCO3 (0.05M) was pumped to the SCWFR. The reactants were heated at 50–400 ◦C for 2 minutes 478 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 under 25 MPa. Glycine, alanine, beta-alanine, gamma-aminobutyric acid, delta- aminovaleric acid and epsilon-aminocaproic acid were detected in the products by amino acid analysis systems (post column fluorescence derivatization). In this study, starting solution of KCN and HCHO whose concentration was as low as 0.0001 M could be used to obtain amino acids for the first time. In another type of oligomerization reactions 100 mM glycine solution was heated for 2 minutes at 200–400 ◦C under 25 MPa. Some glycine molecules were changed to give diketopiperazine, diglycine, triglycine, tetraglycine together with some other unknown compounds in the products. At 400 ◦C, those oligoglycine were not detected, but glycine was increased after acid-hydrolysis, which suggested that unknown glycine condensates were produced even under supercritical conditions. The present results suggest that formation and oligomerization of amino acids can occur in submarine hydrothermal systems, even in supercritical water.

AMINO ACIDS IN DEEP-SEA HYDROTHERMAL SUB-VENT AT SUIYO SEAMOUNT, IZU-BONIN ARC, PACIFIC OCEAN Yoshinori Takano1, Tsukasa Horiuchi1, Yae Edasawa1, Kensei Kobayashi1,Kat- sumi Marumo2 and Tetsuro Urabe3 1 Department of Chemistry and Biotechnology, Yokohama National University, Hodogaya-ku, Yoko- hama 240-8501, Japan (e-mail: [email protected]); 2 National Institute for Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8566, Japan; 3 Department of Earth and Planetary Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan

Since the discovery of Galapagos submarine hot spring, deep-sea hydrothermal systems have been proposed to be possible environments for chemical evolution and the origins of life on Earth. So far number of particular submarine ecological colonies have been recognized near black or clear smokers and its organic rich seaﬂoor mat. Recently, ocean drilling projects on submarine hydrothermal vent started to explore subjacent frontier of biosphere, which was named “Archaean Park Project” (Urabe, 2001). Amino acids are common essential components of all terrestrial organisms. Here we studied the vertical distribution of amino acids and their stereo chemistry in the core samples which was collected in such extreme environments as at 308◦ and 15 MPa. Deep-sea hydrothermal sub-vent boring core samples were collected in the Ar- chaean Park Project Cruise for Suiyo seamount, Paciﬁc Ocean (28◦33’ –, 140◦39’ E). Amino acids were extracted from the core samples, hydrolyzed, and determined by ion exchange HPLC. D/L ratio of the amino acids was measured by reversed- phase HPLC after pre-column derivatization with o-phthalaldehyde and N-acetyl- L-cystein. Phosphatase activity of the core sample was also measured with p- nitrophenyl phosphate as a substrate. Vertical distribution of amino acid concentration, D/L ratio of amino acids and phosphatase activity supported the presence of subjacent vigorous microbial new ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 479 oasis, which was also suggested by microbiological studies of the core samples. Signatures for the abiotically-formed amino acids, such as high D/L ratio and pre- dominance of α-amino acids [2] were not observed. It is suggested that terrestrial habitable zone is widespread below submarine hydrothermal vent areas. This research is funded by the MEXT, Japan through Special Coordination Fund “Archaean Park” project.

References

T. Urabe et al.: 2001, Japan Earth and Planetary Science Joint Meeting, Tokyo, Cm-001. Md N. Islam et al.: 2001, Anal. Sci., in press.

STRONG FLUCTUATIONS IN HYDROTHERMAL SYSTEMS AS INITIAL IMPULSE FOR THE ORIGIN OF LIFE Kompanichenko V. N. Institute for Complex Analysis, 31 Gerasimov Str., Khabarovsk 68021, Russia; [email protected]

Both of the global aquatic mediums of rocky planets which are considered as alternative areas for the origin of life – hydrothermal systems and ocean – possess three obligatory conditions for this process: availability of liquid water, organic compounds and source of energy (light, heat and chemical ones). However, these exists the great difference between these mediums that is significant for the origin of life. In fact, ocean represents passive layer of water with constant hydrostatic pressure. Hydrothermal systems are the area of contradictory interaction between active hydrodynamic pressure of rising fluids and passive lithostatic pressure of country rocks that continuously maintains strong changeability (fluctuations) of parameters: internal pressure, temperature, concentrations of compounds, pH, etc. Strong fluctuations in the medium is the forth obligatory condition for the origin of life formerly argued by the author. Strong gradients and high temporal changeability of parameters create the medium where the non-spontaneous processes, proceeding in organic microsystems against the gradients (active transport, etc.), have a chance to attain the self-maintaining level thanks to self-organization. So, hydrothermal systems beneath the surface of rocky planets and satellites, where non-equilibrium display is much higher, can be considered as the most appropriate medium for the probionts origination. The best conditions for their subsequent development are in the areas around submarine hot springs. Significant gradients and fluctuations, still taking place here, urge on development of these initial sparks of life, and the surrounding vast ocean opens boundless opportunities for their future advancement. Conditions in hydrothermal systems on the early Earth are better correspond to those in present hydrothermal systems, which are connected with basaltic/ultrabasic magmatism and located on festoon islands and oceanic ridges. 480 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

PREBIOTIC EVOLUTIONARY SIGNIFICANCE OF THE INTERFACE CHEMISTRY IN HYDROTHERMAL ENVIRONMENTS Koichiro Matsuno and Ei-ichi Imai Department of BioEngineering, Nagaoka University of Technology, Nagaoka 940-2188, Japan, e-mail: [email protected]

Hydrothermal vents on the sea floor in the ocean are unique in providing exotic environments for synthetic chemical reactions taking place there. Mixing of the hot water out of the vents with the cold water in the surroundings naturally comes to prepare a wide variety of dynamic interfaces between the two. In order to estimate the prebiotic significance of the interface chemistry, we compared two reaction systems: First one is the one dominated by the volume chemistry, in which the system experiences temperature changes as a whole. Another one is the one dominated by the interface chemistry which houses a lot of dynamic and heterogeneous interfaces between hot and cold waters internally. When the reaction solution included only glycine as a reactant and when the temperature of the solution changed from 250 degrees C down to 0 degree C repeatedly in a circulating manner, our experimental model of the interface chemistry was found to give the yields of triglycine over 1000 times greater than those available from the volume chemistry. This observation manifests that geological conditions, especially those dynamic ones providing various interfaces between hot and cold water near hydrothermal vents in the ocean, would have played a significant role in chemical evolution on our Earth and probably elsewhere, also.

EVOLUTIONARY DIVERSIFICATION OF A PREBIOTIC REACTION SOLUTION OF AMINO ACIDS IN HYDROTHERMAL ENVIRONMENTS Shinnosuke Yokoyama, Hajime Honda, Ei-ichi Imai, Kuniyuki Hatori and Koichiro Matsuno Department of BioEngineering, Nagaoka University of Technology, Nagaoka 940-2188, Japan, e-mail: [email protected]

We examined a time development of the reaction solution of glycine (G), alanine (A), valine (V), and aspartic acid (D) in a ﬂow reactor simulating a hydrothermal environment over the time interval of 120 minutes, in which the reaction solution circulated through both the hot (225 degrees C) and cold (0 degree C) region repeatedly in a closed manner. No oligomers were present in the initial solution. The HPLC elution patterns of the reaction products, comprising more than 30 different chemical species, demonstrated temporal changes. We ran the similar experiments many times as starting from the same initial conditions to the extent our experimental controllability permitted. The GAVD reaction solution turned out to exhibit an evolutionarily phylogenetic tree consisting of both divergence and convergence of the robust groupings of the products, and eventually divergence dominated. The robust divergence of the tree was obtained out of more than twenty independent ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 481 runs of the similar evolutionary experiments over 120 minutes. The present experimental observation of robust divergence of the phylogenetic tree comes to suggest to us that the notion of chemical evolution would apply even to the reaction solution as a whole as an ecosphere, in addition to each chemical species to be synthesized prebiotically.

A DIFFERENCE IN REACTION PATHWAYS BETWEEN A STEADY AND UNSTEADY MOLECULAR SYSTEM Shigeru Sakurazawa Future University-Hakodate, School of System Information Science, 116-2 Kamedanakano, Hakodate, Hokkaido 041-8654, Japan

Several studies have proven the ability of submarine hydrothermal vents of up to 200 ◦C to polymerize peptides under assumed prebiotic conditions. Almost all of these experiments were done under a condition of steady temperature. On the other hand, the relaxation time of a polymer becomes longer as the polymer becomes larger. In this case, an environmental change that occurs at a high enough speed may bring a reaction that does not occur under a steady state, since the reaction progresses before the molecules reach equilibrium state. In this investigation, peptides and thermal heterocomplex molecules of amino acids in aqueous solution were heated in two kinds of reactors. One was a reactor kept at a steady 90 ◦C, and the other reactor was a ﬂow reactor with 4 ◦Cand 90 ◦C parts circulated by a tube pump. Each product from these two reactors was analyzed by HPLC. It had already been veriﬁed that the peptides and the thermal heterocomplex molecules did not changed at 4 ◦C. A difference in the thermal decomposed products of the two reactors was observed. This result suggests that even if these two reactions progressed at the same temperature of 90 ◦C, each had a different pathway. This means that these molecular systems depend on their own history. In a study of chemical evolution, the behavior of a molecule in changing environment should be discussed.

THE CO2 TO FORMALDEHYDE REDUCTION ON PYRITE CATHODE AT HIGH PRESSURE: A MODELING OF ELECTROCHEMICAL PRO- CESS IN HYDROTHERMAL SULFIDE ORE DEPOSITS M. G. Vladimirov1∗, Y. F. Ryzhkov2,V.A.Alekseev2, V. A. Bogdanovskaya3 ,M. S. Kritsky1 and V. A. Otroshchenko1 1 A.N. Bach Institute of Biochemistry, RAS, Moscow; 2 The Russian Federation State Research Center, “Troitsk Institute for Innovation and Fusion Research”, Troitsk, Moscow Region; 3 A.N. Frumkin Institute of Electrochemistry, RA S, Moscow; Russia. ∗ e-mail:

The minerals composing sulfide ores show a great diversity in their electrode potentials. In hydrothermal solutions these minerals can give rise to galvanic circuits, 482 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 which cathode potential values are sufficient to reduce CO2. This makes to suspect participation of such electrochemical systems in the organic substances formation. To verify this hypothesis in modeling experiment, a fluorocarbon electrochemical cell was constructed. The cell consisted of two separated electrode chambers. The cathode (7 cm2) was manufactured of a natural pyrite monocrystal and anode was a platinum plate. The cell’s electrodes were connected with a programmed potentiostate and the recording unit. The cell was installed into a high-pressure –1 autoclave permitting a continuous CO2 flow (50 atm, 10 ml·min ) through the 0.1 M KHCO3 electrolyte. The CO2-saturated solution was subjected to electrolysis (24 hrs, room temperature). Starting with a cathode potential about 800 mV (vs. saturated Ag|AgCl r.e.), the accumulation of formate in electrolyte was observed in process of electrolysis. The formate yield demonstrated an exponential growth as a function of cathode potential value at least up to 1,200 mV. The maximal faradaic efficiency of formate synthesis (0.12%) was observed at 1,000 mV. Almost no formate was formed at the normal baric pressure or when the potential difference applied to electrodes was equal to zero. Both in the experiments and control trials no formaldehyde was detected among products. The results may point to the CO2 cathode reduction as a source of organics in hydrotherms accompanying the sulfide ore deposits (deeper than 500 m beneath the crust surface) and in “black smokers” on the ocean floor. ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 483

MOLECULAR EVOLUTION AND GENOMICS 484 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

HUMAN RETROPSEUDOGENES. A GENOMIC AND EVOLUTIONARY ANALYSIS Sergio Barberan-Soler, Alfonso Vilchis-Peluyera, Luisa Alba-Lois and Víctor Valdés- López Laboratorio de Biología Molecular. Departamento de Biología Celular. Facultad de Ciencias. Uni- versidad Nacional Autonoma de México (UNAM). Circuito Exterior, Ciudad Universitaria. Coyoacán, 04510. México D. F. Tel. (55)56-22-48-31. e-mail: [email protected]

The reported draft sequence of the human genome (1, 2), has attracted a lot of interest. A great deal of attention has been focused in medical and biotechnological aspects of the 40,000 or so genes found in the human genome. However, the coding sequences comprise no more than 2% of the total base pair complement. Even, considering the complete gene sequences (introns included), the human genome has more than 75% of its nucleotides corresponding to sequences which are not themselves part of our genes. These sequences have often been described as “junk DNA” and, as no function has yet been ascribed to them, have been regarded as molecular parasites. However, they actually contain an extraordinary amount of information about biological processes and about the evolution of the genome. Most of this part of the genome corresponds to several classes of transposable repeated sequences, mainly of the retroviral-like type. As part of their dispersion mechanism, some of these elements encode a reverse transcriptase. As a consequence of this activity, occasionally, a cytoplasmic mRNA is used as a template and a processed copy is retroposed back into the genome. Initially, the sequence of the copy can have the open reading frame of the original mRNA, but once in the genome, it usually lacks the regulatory signals to promote its transcription. Hence, lacking the evolutionary pressures to maintain a speciﬁc sequence the copy starts to accumulate nucleotide changes that further inactivate it becoming then a retropseudogene. It should be noted that in this respect retropseudogenes can be utilized as molecular clocks, as their divergence of the original mRNA copy can be traced back. These molecular events have produced a notable amount of retropseudogenes in our genome. In this report we present a preliminary analysis of some of them. In short, we have obtained and compared the nucleotide sequences of interspersed retropseudogenes. The evolutionary dendrograms have been constructed and the times of divergence calculated. As a tentative conclusion we have obtained evidence of a non random process, reﬂecting two types of events. First, a possible evolutionary increase in the transcription rate of particular genes, which could depend on adaptive pressures. And second, a series of genomic duplication events, as revealed by “families” of individual retropseudogenes.

References

Lander, E. S.: 2001, Initial sequencing and analysis of the human genome, Nature 409, 860–921. Venter, J. C. et al.: 2001, The sequence of the human genome, Science 291, 1304–1351. ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 485

SIMPLE SEQUENCES: IT IS SOMETHING YOU HAVE WHETHER YOU LIKE IT OR NOT Arturo Becerra1, Germinal Cocho2, Luis Delaye1 and Antonio Lazcano1 1 Facultad de Ciencias, UNAM; 2 Instituto de Física, UNAM Cd. Universitaria, 04510 México, D.F., Mexcio

Low complexity regions (LCR), also known as simple sequences are segments of proteins and nucleic acids which are biased in residue composition, and which typically contain repetitive segments. Due to their hypermutable character, LCR have been recognized as a significant source of random phenotypic variation in prokaryotic pathogens (Moxon 1999; Moxon and Wills 1998). In order to obtain insights on the phylogenetic distribution of simple sequences and their biological properties, we have analised 68 complete cellular proteomes using the SEG program (Wootton and Federhen 1993). Our results indicate that simple sequences (a) are not monophyletic, and have a wide phylogenetic distribution which indicates that their appearance is older than pathogenicity; (b) are not restricted to a unique enzyme class, but are present in ORFs encoding a wide spectrum of catalytic and structural proteins of many different biological functions; (c) although they tend to be present at the carboxy- or amino- ends of proteins or in segments connecting well-defined structures, in few significant cases they are part of functional domains; (d) the natural amino acid composition of each complete proteome is enhanced in their corresponding simple sequences, which exhibit a compositional bias as shown by their abundance of alanine, leucine, lysine, serine and glutamine, and the under- representation of histidine, tryptophan, and cysteine. This is particularly evident in hyperthermophiles, whose homopolymeric tracts are enriched in glutamine in both the Bacterial and Archaeal domains.

References

Moxon, E. R.: 1999, Whole-Genome Analysis of Pathogens, in Stephen C. Stearns (ed.), Evolution in Health and Disease, Oxford Press, New York. pp. 191–204. Moxon, R. and Wills, C.: 1998, DNA microsatellites, agents of evolution? Sci. Am. 28, 72–77. Wootton, J. and Federhen, S.: 1993, Statistics of local complexity in amino acid sequence and sequences database, Compt. Chem. 17, 149–163.

THE EVOLUTIONARY LINK BETWEEN NITROGEN FIXATION AND BACTERIAL PHOTOSYNTHESIS Renato Fani, Laura Cioni, Matteo Brilli, Antonio Lazcano1 and Pietro Liò2 Dip. to di Biologia Animale e Genetica, Firenze, Italy; 1 Departamento de Microbiologia, UNAM, Cd Universitaria, Mexico; 2 Genetics Dept. Cambridge University, Cambridge, UK

Nitrogen fixation is a well characterized metabolic process involving several genes (nif), but very little is known about its origin and evolution. A detailed analysis of 486 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 nif gene products revealed that nifDK and nifEN, encoding the α and β subunits of nitrogenase, and the components of the NifEN enzymatic complex, involved in FeMo-Co biosynthesis, belong to a paralogous gene family. This analysis also permitted to trace their possible evolutionary history; according to the proposed model the four genes are the result of two successive duplication events, very likely predating the appearance of the Last Universal Common Ancestor (LUCA). The first paralogous duplication event involved an ancestral gene (encoding a low specificity ezyme able to catalyze several reactions) leading to a bicistronic operon which, in turn, underwent a paralogous operon duplication event originating the ancestors of the present-day nifDK and nifEN operons. A further analysis revealed that these genes exhibited a significant degree of sequence similarity to the bacterial bchB and bhcN genes, which code for two components of protochlorophyllide reductase, and to the products of bchY and bchZ, encoding two components of chlorin reductase. These enzymes catalyze two sequential steps in bacteriochlorophyll biosynthesis. It has been previously shown that bchB and bchY are paralogous genes, as well as bchN and bchZ. Data obtained strongly suggested that bchB, bchN, bchY,andbchZ belong to the nifDKEN paralogous gene family, that they might have arisen from two successive duplications involving one of the two operons above mentioned, and established an evolutionary link between nitrogen fixation and bacteriochlorophyll biosynthesis.

EVOLUTION AND BIOCHEMICAL CORRELATIONS BETWEEN nifV AND leuA GENES Matteo Brilli, Elena Tamburini, Duccio Cavalieri, Francesca Burgalassi and Renato Fani Dipartimento di Biologia Animale e Genetica, Via Romana 17-19, F-50125 Firenze

The enzymes α-isopropyl malate (α-IPM) synthase (EC 4.1.3.12) and homocitrate (HC) synthase (EC 4.1.3.21) catalyze very similar condensation reactions. α-IPM synthase, encoded by leuA, is responsible for the condensation reaction between acetyl coenzyme A and α-ketoisovalerate, and represents the first enzyme in the leucine biosynthetic pathway in both bacteria and Eucarya. HC synthase catalyzes the condensation reaction between acetyl CoA and α-ketoglutarate. In most prokaryotes the product of this reaction (homocitrate) is involved in nitrogen fixation, representing the organic moiety of the nitrogenase cofactor whereas in Fungi and some deep branching bacteria it is involved in the lysine biosynthetic pathway; the gene encoding for HCsynthase is referred to as nifV or lys20, respectively. The availability of complete archaeal, bacterial and eucaryal genomes enabled a detailed comparative analysis of the leuA, nifV and lys20 gene products which revealed a high degree of sequence similarity between them. This finding suggested a common origin of their encoding genes from an ancestral one by paralogous duplication followed by evolutionary divergence and predating the appearance of LUCA (Last Universal Common Ancestor). A further and deeper analysis also per- ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 487 mitted to depict a possible evolutionary pathway leading to the present-day genes. The model proposed supports the patchwork hypothesis on the origin and evolution of metabolic pathways; accordingly the ancestral gene might have encoded for an aspecific enzyme able to catalyze both the reactions carried out by HC synthase and IMP synthase. The model proposed also predicts that at least four different metabolic pathways, i.e. the biosynthesis of leucine and lysine, the synthesis of cell wall and nitrogen fixation were strictly interconnected.

EVOLUTION OF TIM BARREL: MULTIPLE GENE ELONGATION EVENTS IN HisA Matteo Brilli, Pietro Liò1, Antonio Lazcano2 and Renato Fani University of Florence, Dept of Animal Biology and Genetics, Via Romana 19, Firenze, Italy; 1 Genetics Dept., Cambridge University, Cambridge, UK; 2 Dept. of Microbiology, Facultad de Ciencias, UNAM, Cd Univeristaria, D.F., Mexico

The TIM barrel structural family is an important group of proteins that share a typical structure constituted by eight β-strand/α-helix elements arranged circularly to form a barrel. This structure is very stable and versatile concerning the catalytic activities of its members. The origin of this large family is still highly debated, since they possess an almost identical tridimensional structure, but they do not share signiﬁcative sequence similarities. This led to the assumption that these proteins evolved by a phenomenon of convergent evolution towards a very stable and versatile structure. The alternative hypothesis suggests that they have derived from a common ancestor gene by its (multiple) duplication and divergent evolution. Recent data have demonstrated that the hisA gene coding for a TIM barrel protein (ProFAR Isomerase) of about 240 aminoacids arose from an elongation event involving an ancestral gene half the size of the present–day hisA, that encoded for a half-barrel protein probably acting as homodimer. A generally accepted idea is that ancestral cells possessed mini-genes encoding structural /functional motives; for this reason an exhaustive analysis of the available HisA amino acid sequences in the search for internal repeated sub-elements. Data obtained revealed that each half (120 amino acids) of the HisA protein can be further subdivided in four shorter modules of 30 aminoacids, corresponding to a single ?t?g motif. They showed a high degree of sequence similarity between them to suggest their common origin from a mini-gene (of about 90 nucleotides) which underwent to three gene elongation events originating the complete gene, encoding for an entire TIM barrel. 488 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

STRUCTURE AND EVOLUTION OF THE HISTIDINE BIOSYNTHETIC PATHWAY Matteo Brilli, Antonio Lazcano1, Pietro Liò2 and Renato Fani Dipartimento di Biologia Animale e Genetica, Firenze, Italy; 1 Departamento de Microbiologia, UNAM, Cd Universitaria, México; 2 Genetics Dept., Cambridge University, Cambridge, UK

The histidine biosynthetic pathway is one of the best characterized anabolic pathway. There are many clues indicating the antiquity of this pathway, suggesting that it might have been completely assembled before the appearance of the last common ancestor and that its origin probably started in the early stages of molecular evolution. In fact, the synthesis of histidine under prebiotic conditions suggests that it was available in the primordial soup and that the pathway might have evolved as a consequence of the exhaustion of the prebiotic supply of histidine. The availability of completely sequenced genomes from different (micro)organisms belonging to the three cell domains permitted a deep analysis of his genes, which revealed that paralogous gene elongation and duplication events occurred frequently and that they played a major role in shaping the pathway. Moreover, we found that (at least) seven his genes underwent different gene fusion events in some bacterial and eucaryal lineages, but not in Archaea, suggesting that the ancestral his pathway was constituted by mini-genes which underwent different rearrangements during evolution. Data obtained also suggested that some his genes are the descendants of genes encoding less speciﬁc enzymes, supporting the Patchwork hypothesis. The analysis of his genes organization in the three cellular domains revealed that only in some Bacteria and in Sulfolobus they are arranged in compact operons; in the other (micro)organisms where at least some his genes have been sequenced, they are scattered on the genome or organized in short clusters. If the ancestral his genes were organized in operons, they might have underwent different rearrangements in the diverse phylogenetic lineages.

ON THE CLASSES OF AMINOACYL-tRNA SYNTHETASES AND THE AMINO ACIDS Andre R.O. Cavalcanti1, Elisa Soares Leite2, Benício B. Neto2 and Ricardo Ferreira2 1 Department of Ecology and Evolutionary Biology, Princeton University, Princeton – NJ USA; 2 Departamento de Química Fundamental, UFPE, Recife – PE Brazil; Corresponding author: Andre R. O. Cavalcanti, Address: Department of Ecology and Evolutionary Biology, Princeton University, Princeton – NJ USA, Phone: 609 – 258 -16 56, e-mail: [email protected]

The division of the aminoacyl-tRNA synthetases in two classes is compared with a division of the amino acids in two classes, obtained from the AAIndex databank by a principal component analysis. The division of the enzymes in Classes I and II follows to a great extent a division in the chemical and biological properties of their cognate amino acids. We argue that the evolution of Class I synthetases was ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 489 determined by the characteristics of their corresponding amino acids, but the same does not hold true for Class II enzymes. We interpret these results considering models for the origin of the genetic code in which an initial version, containing fewer amino acids, was modiﬁed by the incorporation of new amino acids, the amino acids of Class I being incorporated after those of Class II.

HALOTOLERANCE AND HALOPHILISM PROPERTY MORE THAN AD- APTATION TO ENVIRONMENT (High Frquency of DNA duplex TT in genes that grant halotolerance) Federico Minchaca Sanjuan

In this work there are two types of findings or productions of knowledge: a) The empirical findings obtained by the analysis and the observation and but specifically in this case by the identification of patterns of the halotolerance genes. b) The methodologic findings of the state of the art that not only by a bibliographical revision but by the analysis of the proposed theories that connect the halotolerance with different types stress and evenl with the geological differences with respect to the abundance of NaCl in the planet. Within the empirical findings it was found: 1) A determined pattern in the halotolerance genes which is completely different from the patterns of another type of studied genes up to date. 2) The high frequency of the DNA duplex TT in genes that determine halotolerance independently of taxa or complexity the organism that had the gene that determines the analyzed halotolerance. The high frequency of DNA duplex TT was observed in all the genes that were used for this work independently of their type (except for determining halotolerance). 3) The Ohno’s Rule is not always fulfilled in the analyzed genes, being observed in 16 S RNA genes belonging this to organisms evolutively primitive (Archeae, Protobacterias, Cyanobacterias). 4) It was observed a high frequency of 16 ARN of S like genetic material in the genes that determine halotolerance. As result of the methodological work of this is proposed the Halotolerance is more that an adaptation to saline stress, it represents the form more primitive of life on Earth reason why is suggested that the evolutionarily primitive genes could be those that allow the halotolerance and the halophilism.

EVOLUTION OF PROTEIN SYNTHESIS (TOWARDS AN AMINO ACID CHRONOLOGY) William J. M. F. Collis e-mail: [email protected]

In this follow up to a poster first presented at ISSOL ’99, we analyze the amino acid content of conserved pairs of amino-acyl tRNA synthetases (aars) and score 490 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 these with an initially arbitrary hypothetical amino-acid chronology. This temporal order is successively refined by making small changes to it until a ‘best’ score is reached. Of some 300 conserved residues, some 94% are consistent. We show that the resulting order is also consistent with aars phylogenetic trees, biosynthetic order, and a possible initial AG two base genetic code as predicted by Crick & Orgel (1968). We confirm that class II aars are older than class I. The derived amino-acid order can be used to date other ancient proteins which originated in LUCA such as the transaminases.

EARLY EVOLUTION OF RNA-BINDING DOMAINS Delaye, L.2, Abascal, F.1, Fernández, J. M.1, Valencia, A.1 and Lazcano, A.2 1 Protein Design Group, Centro Nacional de Biotecnología, Universidad Autónoma de Madrid, Can- toblanco, España; 2 Laboratorio de Microbiología, Departamento de Biología Evolutiva, Facultad de Ciecnias, UNAM, México D.F.

Comparisons of complete cellular genomes indicate that a set of genes whose product synthesize, degrade, or interact with RNA molecules are among the most highly conserved sequences common to all living beings, and therefore may have been present in their last common ancestor, i.e., the cenancestor. This ﬁnding may be interpreted as evidence of an ancestral RNA-protein world. In order to obtain insights on the evolution of sequences which may date from this evolutionary period prior to the emergence of DNA genomes, we have analyzed the phylogenetic distribution of RNA-binding domains of this highly conserved molecules as well as other RNA-binding domains in the swissprot database using PSI-BLAST searches and the expert database system ORFandDB which aloud the performance of correlated questions. We have also looked for the phylogenetic relationship of this molecules as reveled by their tertiary structures in SCOP. The characteristics of these highly conserved amino acid stretches which are essential in RNA metabolism will be discussed.

DNA HOMOGENEITY INDEX AS A TOOL FOR STUDYING INTER- DOMAIN HORIZONTAL GENE TRANSFER Peredo, D., Sierra, C., Delaye, L. and Lazcano, A. Laboratorio de Microbiología, Departamento de Biología Evolutiva, Facultad de Ciecnias, UNAM, México D.F.

The reconstruction of ancestor-descendant relationships between extant species is one of the aims of evolutionary biology. In this sense, rRNA phylogenies were believed to reﬂect accurately the propinquity of descendant between all species. However, with the advent of complete genome sequences, it has become clear that the evolutionary history couldn’t be precisely described only by a dichotomous scheme of only one gene, specially because of the phenomenon of horizontal gene ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 491 transfer (HGT) between procaryotic cells. Although such paradigm is true in some degree, as is shown by looking at the concordance between rRNA phylogenies and phenograms constructed using complete genomes, since then, it has become important to understand how frequent such a process is. New ways of studying HGT are a powerful way of pushing fresh air into this question. Here, we decided to study the DNA homogeneity index (DHI) based on a binary distribution model (Miramontes et, al., 1995) as a tool for studying inter-domain cases of horizontal gene transfer. Particularly, we use the mitochondria-like chaperonin 60 gene from Giardia lamblia as a case-study, as it has been suggested that the gene encoding this protein was horizontally transferred from an ancestral hypothetical mitochondria to the nucleous (Roger et al., 1998). The results will be discussed to assess the potential of this methodology to understand phylogeny in more detail.

THE EVOLUTION OF FATTY ACIDS METABOLIC PATHWAYS: A GEN- OMIC PERSPECTIVE J. Javier Diaz-Mejia and Antonio Lazcano footnotesize Facultad de Ciencias, Universidad Nacional Autonoma de Mexico, NH∼XICO, e-mail: [email protected]; [email protected]

Fatty acids (FAs) have played a dual role in biology. Structural by means of it’s biosynthesis and incorporation into phospholipids, but also energetic by it’s degradation in the beta-oxidation, helping to produce ATP. The contemporary FAs metabolism pathways could not be present in ancient biochemical anaerobic systems because: i) shares hydration/dehydration steps which involves hydroxyl radicals, ii) are linked to oxygen dependent pathways (by means of it’s cofactors), iii) some steps are thermodynamically unfavorable, and iv) requires ATP and other molecules, difﬁcult to be present in ancient systems. This could suggest that the ancestral role of fatty acids and their metabolism machinery were different to the contemporary. In this work, the biological distribution of the of enzymes of the FAs metabolism pathways was determined; a phylogenetic hypothesis of these enzymes was constructed, by means of primary, secondary and tertiary structure based analysis; and an evolutionary scenario about a common origin of the entire contemporary FAs metabolism pathways (degradative and biosynthetic), which include other pathways with similar processivity and homologue enzymes, as the Krebs cycle and several other acyl-CoA esters metabolism pathways, was proposed. In this scenario, the hydroxyl radicals-involving reactions, the thermodynamically favorable steps of these pathways, are proposed as the most recently (under biochemical aerobic conditions), and independently incorporated to each pathway. 492 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

GENOMIC TREE OF 52 PROKARYOTES Sorel T. Fitz-Gibbon1 and Christopher H. House2 1 IGPP Center for Astrobiology, University of California, Los Angeles, CA 90095-1567; 2 Penn State Astrobiology Research Center & Department of Geosciences, Pennsylvania State University, 208 Deike Building, University Park, PA 16802 [email protected]

Published genomic trees have been remarkably similar to rRNA trees and trees based on the analysis of multi-gene datasets. Here, a prokaryotic tree has been constructed using MP analysis of the presence and absence of protein families (homologs) within each of 52 genomes. There are features not congruent with typical rRNA phylogenetic trees, which appear to result from several different artifacts. The basal most clade of the Bacteria is composed of pathogens with small genomes, i.e. Spirochaetes, Chlamydias, and a clade of small (< 800 genes) ‘Low GC’ gram positives, split away from the large (>1600 genes) ‘Low GC’ gram positives. Further, the Euryarchaeota appear divided into two clades with the two Thermoplasma genomes and Halobacterium sp. in a clade basal to the Crenarchae- ota. These later taxa, when included, in turn, move the placement of several basal bacterial lineages to derived states. When the analysis is repeated after excluding the thirteen smallest genomes (i.e. smaller than that of free-living Aquifex aeolicus [1.5 M]), and after removal of the ‘misplaced Euryarchaea’, the resulting tree is transformed into a topology quite consistent with rRNA taxonomy. All of the Proteobacteria and all of the Gram positive bacteria are each united into clades. The 13 small genomes are problematic presumably because of extreme gene loss, whereas the reasons for Halobacterium and Thermoplasma being problematic are not yet understood, but may result from lateral gene transfer between these taxa and Bacteria or from signiﬁcant gene loss. While the Halobacterium and Thermoplasma genomes used are of 2.57 and 1.58 Mb, respectively, Halobacterium salinarium has a genome of 4.0 Mb indicating that the ancestral state of the halophiles may be a large genome. Future inclusion of larger genomes from these groups may result in a tree with the correct topology.

THE FISH-SIMS APPROACH: DIRECT GEOCHEMICAL ANALYSIS OF MICROORGANISMS REVEALS ISOTOPIC IMPRINTS OF METHANE IN DIVERSE MICROBIAL ASSEMBLAGES Christopher H. House1, Victoria J. Orphan2, Kai -U. Hinrichs3,KevinD.McKeegan4 and Edward DeLong2 1 Penn State Astrobiology Research Center & Department of Geosciences, Pennsylvania State Uni- versity, 208 Deike Building, University Park, PA 16802 USA [email protected]; 2 Monterey Bay Aquarium Research Institute, Moss Landing, CA, 95039, USA; 3 Department of Geology & Geophysics,Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA; 4 Department of Earth & Space Sciences, University of California, Los Angeles CA, 90095, USA ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 493

Parallel phylogenetic gene surveys and isotopic determination of lipid biomarkers in methane-rich seep sediments suggested that diverse archaeal and bacterial assemblages are involved in the anaerobic oxidation of methane (AOM). Specifically, a novel clade of Archaea related to known methanogens (ANME-1 group), as well as microorganisms affiliated with the Methanosarcinales (ANME-2 group) and their syntrophic sulfate-reducing bacterial partner affiliated with the Desulfosar- cina, have been identified as likely candidate methane-oxidizing microorganisms. Both 16S rDNA and lipid analyses provide only circumstantial evidence linking these specific groups to AOM, however, because they are based on bulk analyses of whole sediments, rather than on the level of single microorganisms. In this study, we provide further evidence directly linking two distinct groups of Archaea, the uncultured consortium archaeal ANME-2/ bacterial Desulfosar- cina spp. and the archaeal ANME-1 to methane consumption in anoxic marine sediments. Using a novel approach combining fluorescent in situ hybridization (FISH) and secondary ion mass spectrometry (SIMS), we identified aggregations of ANME-2/ Desulfosarcina and single cells and aggregates of ANME-1 from methane seep sediments and directly determined the carbon stable isotopic composition for the individual cells and cell aggregates. Both archaeal groups ANME-1 and ANME-2 displayed isotopic signatures suggestive of methane assimilation, with extreme 13C depletion (down to –96 per mil). In comparison, the carbon isotopic composition of microorganisms from the same sample not targeted with either the archaeal ANME-1 or ANME-2 specific rRNA probe sets had 13Cvalues averaging –30 per mil. Interestingly, large bacterial filaments resembling sulfide- oxidizing Beggiatoa were slightly more depleted in 13C (approx. -50 per mil), and may signify ecosystem-wide incorporation of methane-derived endproducts. The combined application of FISH and SIMS serves as a new useful tool in geomicrobi- ology and for astrobiology for deciphering the metabolic function of environmental microorganisms in situ.

GENOMIC TREE OF EUKARYOTES Christopher H. House1 and Sorel T. Fitz-Gibbon2 1 Penn State Astrobiology Research Center & Department of Geosciences, Pennsylvania State Uni- versity, 208 Deike Building, University Park, PA 16802 [email protected]; 2 IGPP Center for Astrobiology, University of California, Los Angeles, CA 90095-1567

Despite years of research, important phylogenetic relationships within the non- protist Eukaryotes remain uncertain. In particular, the uniting of Animalae and Fungi to the exclusion of the Plantae is only weakly discerned through single gene analyses (Kumar and Rzhetsky, 1995), and the exact placement of the Nem- atoda phylum with respect to the other animal phyla is highly disputed (Blair et al., submitted). Although nematodes, which have a pseudocoelom, have tradition- ally been placed in a phylogenetic position basal to animals with a true coelom (Coelomata), a recent analysis of 18S rRNA genes has placed the nematodes in 494 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 a clade (Ecdysozoa) comprised of moulting animals, including the Arthropoda (Aguinaldo et al., 1997). This alternative phylogeny of (the Ecdysozoa hypothesis) has gained wide acceptance within developmental biology, inﬂuencing many interpretations of early animal evolution. However, the Ecdysozoan hypothesis, remains debatable because some phylogenetic analyses based on protein sequences suggest that it is not correct (Wang et al., 1999; Blair et al., submitted), and because the moulted cuticles of arthropods and nematodes seem not to be homologous. We constructed a phylogenetic tree based on whole-genome data from ﬁve eukaryotes, and three crenarchaeotes (as an outgroup). The resulting rooted tree indicates that the Animalae are united to the exclusion of the Plantae, and supports the traditional Coelomata hypothesis, placing Caenorhabditis elegans (Nematoda) basal to Dro- sophila melanogaster (Arthropoda) and Homo sapiens (Chordata). We demonstrate the resilience of this result by repeating the analysis after increasing pairwise match scores for nematode genes.

ARE GENOME SIZE AND METABOLIC ABILITIES IN BACTERIA AND ARCHAEA THE OUTCOME OF GENOME DUPLICATIONS? Sara Islas and Antonio Lazcano Departamento de Biología Evolutiva, Facultad de Ciencias, UNAM, Apdo. Postal 70-407, Cd. Universitaria, México D.F, 04510, México [email protected]

It has been hypothesized that the increase of DNA content in prokaryotes along evolutionary times is an outcome of sequential large-scale of genome duplications (Wallace & Morowitz,1973; Zipkas and Riley, 1975; Herdman1985). In order to investigate this possibility, a database of 610 organisms was constructed with prokaryotic genome sizes calculated by PFGE as reported in the publications included in the NCBI database PubMed available as of May 2002. The information in this database was completed with a description of the organisms’ phylogenetic positions and lifestyles (optimal growth temperature, response to oxygen, free-living or host-associated). Detailed statistical analyses on the distribution of prokaryotic genome sizes showed that there is a dependent relationship between a genome size and oxygen response. Proteobacteria have the widest range of genome size (Buchnera sp CCE 0.448 Azospirillum lipoferum sp 59b 9.7), while other taxa like Mycoplasmatales (Mollicutes, which are allobligate host-dependent organisms, have the most deﬁned range of genome sizes (0.57–2.5 Mb). In the Archaea domain genome sizes range from the smallest (0.50 Mb)up to 5.5 Mb. When genome size was analyzed with respect to the organism’s oxygen-response as reported in the literature (anaerobes, facultatives, microaerophilic and aerobes), it was found that obligate anaerobic prokaryotes and/or microaerophilic bacteria are endowed with genomes smallest the aerobic bacteria, although there is considerable variation among the latter. Larger genomes are typical of free-living prokaryotes with complex life cycles (Myxobacteria, Actinobacteria Rodospirilaceae), which suggest that these evolved once signiﬁcant amounts of free-oxygen became available ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 495 in the Precambrian environment. Our results suggest that the DNA content of aerobic bacteria is the outcome not of genome duplications, but instead is the outcome of small-scale DNA duplications, slippage, horizontal transfer, and other mechanisms.

References

Wallace and Morowitz: 1973, Chromosoma 40, 121. Zipkas and Riley: 1975, PNAS 72, 1354. Herdman M.: 1985, The Evolution of Bacterial Genomes, in Cavalier-Smith (eds.), The Evolution of Genome Size, John Wiley & Sons Ltd.

RANDOM SEQUENCES OF PROTEINS ARE EXACTLY BALANCED LIKE THE CANONICAL BASE PAIRS OF DNA Vladimir V. Kashkarov1, Alexandr M. Krassovitskiy2,VadimSh.Mamleev3 and Vladimir I. ShCherbak2 1 Department of Physics, al-Faraby Kazakh National University, 71 al-Faraby Avenue 480078 Al- maty, Kazakhstan; 2 Department of Applied Mathematics, al-Faraby Kazakh National University, 71 al-Faraby Avenue 480078 Almaty, Kazakhstan; 3 Kazakh–American University, 18a Satpaev St., 480013 Almaty, Kazakhstan

The DNA canonical pairs of the thymine-adenine and cytosine-guanine residues have 259+”0” and 259+”1” nucleons, correspondingly. Hence, the masses of both canonical pairs are almost balanced. Therefore, the DNA molecule has a constant mass density independently of its information content. As regards peptides, their sufficiently large and random sequences are also balanced in the similar way. The protein consists of the residues of the standard blocks and side chains of the 19 amino acids and 1 imino acid Pro. Their appearance into the random peptide chain is determined by the regular degeneracy of the genetic code. The average density of the standard block residue is equal to 55,934. Among side chains we have proton donors 2*Asp and 2*Glu and proton acceptors 2*Lys and 6*Arg at pH=7. In such a situation, the averaged density of the side chains is also equal to 55,934. Amino acid His somewhere is also considered as a proton acceptor. Its two additional protons insignificantly violate the balance. Thus, in the random protein of infinite length the masses of the standard blocks and side chains are balanced. The random protein that contains approximately 250 amino acid residues the masses of standard blocks and side chains differ from each other not more than in 5,6% with probability 0,95. Hence, the length of the most of primordial natural proteins seems to be sufficient for fulfillment of this balance with high accuracy. However, a random sequence of the triplets corresponds to the protein whose length is about 21 amino acids, if we take into account the 3 termination triplets. 496 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

Thus, one question is raised how the mass balance could appear, if only short sequences existed at the moment of the origin of life. Similar mass balances are discovered inside the genetic code itself (shCherbak, 2002).

References

ShCherbak, V. I.: 2002, Arithmetic inside the Universal Genetic Code. Submitted to BioSystems.

HORIZONTAL GENE TRANSFER MEDIATED BY CORONAE AND LIGHT- NING DISCHARGES ON EARLY EARTH’S OCEANS Jesús Octavio Padilla Hernández1,2, Rosalinda Tapia López2, Elena Álvarez-Buylla2 & Rafael Navarro-González1 1 Laboratorio de Química de Plasmas y Estudios Planetarios, Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México. Circuito Exterior, Ciudad Universitaria, Ap. Postal 70- 543, Coyoacán, Distrito Federal 04510 México; 2 Laboratorio de Genética Molecular, Desarrollo y Evolución de Plantas, Instituto de Ecología, Universidad Nacional Autónoma de México. Circuito Exterior, Ciudad Universitaria, Ap. Postal 70-275, Coyoacán, Distrito Federal 04510, México

Genetic transformation is a powerful tool of genetic engineering that consists in the incorporation of exogenous free DNA by a bacterial recipient which then is able to express the new genotype. This phenomenon is thought to have occurred naturally and continuously during the early biological evolution of life by horizontal gene transfer. In the laboratory such transformations are routinely done subjecting the cells to electric stress. Because in nature such conditions may exist during thunderstorms, Demanèche et al (Appl. Environ. Microbiol. 67(8), 3440– 3444, 2000) investigated the likelihood of cell transformation in soil by simulated lightning. Their results provided the ﬁrst evidence of natural lightning-mediated gene transfer in soils which could enhance bacterial adaptation and evolution. Since the major bacterial metabolic innovations occurred prior to the development of land masses in the early Precambrian, we decided to explore the potential of bacterial transformations by coronae and lightning discharges in aqueous solutions. Our experiments consist of subjecting competence cells of Escherichia coli strain TOP 10 to simulated lightning and coronae discharges in an aqueous medium of Luria- Bertoni in the presence of a plasmid containing a gene encoding for an antibiotic resistence to ampiciline that can be screened for in transformed bacteria colonies (plasmid pRita). Our results strongly suggest that the electric currents developed during thunderstorms on the oceans surface as coronae and lightning discharges are adequate to induce horizontal gene transfer. Therefore, electric discharge processes could have played a key role not only in the origin of life (Miller, Science117, 528; Navarro-González et al., Geophys. Res. Lett. 25(16), 3123-3126, 1998) but also during its evolution (Navarro-González et al,Nature412, 61-64, 2001). ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 497

RELATIONSHIP BETWEEN LYSINE, ARGININE AND LEUCINE ANA- BOLIC PATHWAYS A.M. Velasco and A. Lazcano Laboratorio de Microbiología, Facultad de Ciencias, UNAM, Cd. Universitaria 04510, México D. F. México

The computer analysis of the sequences of all genes involved in the two lysine anabolic pathways: the diaminopimelic acid pathway (DAP) and the alpha- aminoadipic acid pathway (AAA), as well as those genes of the arginine (Arg) and leucine (Leu) biosynthetic routes was performed using the available data from completely sequenced genomes from the three main cellular lineages (Bacteria, Archaea and Eucarya). This kind of analysis offers the possibility of approaching this issue from a genomic perspective, as well as know the biological distribution of these routes. The results of genomic analysis show that the DAP and the Arg routes are related since the products of lysC, asd, dapE and lysA genes from lysine biosynthesis are related to the argB, argC, argE and speAC genes, respectively, whose products catalyze different steps in Arg biosynthesis. On the other hand, the AAA genes LYS20, LYS4 and LYS12 are related with Leu genes leuA, leuC and leuD, and leuB respectively. Finally, we discuss the signiﬁcance of the recent ﬁnding that several genes involved in the Arg and Leu biosynthesis participate in a new alternative route of the AAA pathway (Miyazaki et al., 2001).

References

Miyazaki et al.: 2001, J. Bacteriol. 183, 5067–5073.

BOOTSTRAP, BAYESIAN PROBABILITY AND MAXIMUM LIKELIHOOD MAPPING: EXPLORING NEW TOOLS FOR COMPARATIVE GENOME ANALYSES Olga A. Zhaxybayeva and Johann Peter Gogarten Dept. of Molecular and Cell Biology, Univ. of Connecticut, Storrs, CT 06269, USA [email protected]

We adapted the Maximum Likelihood (ML) mapping to the analyses of all detected quartets of orthologous genes found in four genomes. We have automated the assembly and analyses of these quartets of orthologs given the selection of four genomes. We compared the ML-mapping approach to more rigorous Bayesian probability and Bootstrap mapping techniques. The latter two approaches appear to be more conservative than the ML-mapping approach, but qualitatively all three approaches give equivalent results. All three tools were tested on mitochondrial genomes, which presumably were inherited as a single linkage group. In some instances of interphylum relationships we ﬁnd nearly equal numbers of quartets strongly supporting the three possible topologies. In contrast, our analyses 498 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 of genome quartets containing the cyanobacterium Synechocystis sp. indicate that a large part of the cyanobacterial genome is related to that of low GC Gram positives. Other groups that had been suggested as sister groups to the cyanobacteria contain many fewer genes that group with the Synechocystis orthologs. Interdo- main comparisons of genome quartets containing the archaeon Halobacterium sp. revealed that Halobacterium sp. shares more genes with Bacteria that live in the same environment than with Bacteria that are more closely related based on rRNA phylogeny. Many of these genes encode proteins involved in substrate transport and metabolism and in information storage and processing. The performed analyses demonstrate that relationships among prokaryotes cannot be accurately depicted by or inferred from the tree-like evolution of a core of rarely transferred genes; rather prokaryotic genomes are mosaics in which different parts have different evolutionary histories. Probability mapping is a valuable tool to explore the mosaic nature of genomes.

MOSAICISM IN GENES AND GENOMES Olga A. Zhaxybayeva, Lorraine Olendzenski and J. Peter Gogarten Dept. of Molecular and Cell Biology, Univ. of Connecticut, Storrs, CT 06269, USA [email protected]

The difference between gene trees and organismal evolution has been widely recognized. However, genes are not immutable units of inheritance, and even at the gene level evolution is not always treelike. If multiple similar copies of a gene are present in the same cell, gene conversion events tend to make these two copies of the genes more similar to one another. The conversion tracts are usually much smaller than the lengths of a typical gene. To test the possibility that the rRNA itself is a mosaic, we analyzed 100 aligned representative bacterial 16S rRNA sequences. The full-length alignment and individual parts of the alignment were analyzed using neighbor joining under different distance measures. Each tree topology obtained from a fragment was compared to the tree topology reconstructed from full-length alignment. We found seventeen significant conflicts between topologies reconstructed from full-length alignment and topologies based on different fragments. These disagreements persisted when we repeated the analyses using parsimony method as implemented in PAUP*. Analysis of extended datasets showed that the detected conflicts remained in the presence of additional sequences for most of the seventeen cases. It has been argued that rRNA is a good marker for organismal evolution, because it interacts with many cellular components, and therefore cannot readily be transferred between organisms. However, it has been known for a long time that functioning ribosomes can be reconstituted from parts taken from different organisms, and ribosomal operons of an organism can be replaced with rRNA operons from another species. Our findings indicate that rRNA genes were transferred between related organisms, and that the transferred genes recombined with ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 499 those already present in organisms. Could it be that the congruence between rRNA phylogenies and genome content trees is due to the mosaic nature of rRNA operons and genomes that was generated through similar processes? 500 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 501

MICROBIAL HABITATS 502 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

ALCHICHICA: A SALINE AND HIGHLY ALKALINE LAKE WITH MOD- ERN STROMATOLITES Javier Alcocer1 and Elva Escobar2 1 Laboratorio de Limnología, Proyecto de Conservación y Mejoramiento del Ambiente, UIICSE, FES Iztacala, UNAM. ; 2 Unidad Académica de Sistemas Oceanográﬁcos y Costeros. Instituto de Ciencias del Mar y Limnología, UNAM.

Alchichica is a maar lake located at 19 ◦24N and 98 ◦24W, in the Oriental basin at the border of the states of Puebla, Tlaxcala and Veracruz, at an altitude of 2,300 m above sea level. It is the deepest known natural Mexican lake (i.e. zmax 2 = 64 m; mean depth 38.6 m), with a 1.81 km surface area (lmax 1.7 km; bmax = 1.4 km). Its basin holds saline (TDS 8.3–9 g L−1), alkaline (pH 8.7–9.2) water, dominated by sodium-magnesium and chloride-bicarbonate ions. The annual temperature fluctuates from –5.5 to 30 ◦C with a mean value of 14.4 ◦C. This high-altitude plateau named Los Llanos de San Juan has an arid climate, with an annual precipitation regime less than 400 mm and an annual evaporation rate of 500-600 mm; it has been described as a “cold desert”. This lake is unique in having an almost perfect tufa ring. Tufa forms through a combination of chemical and biologically mediated deposition. Complex assemblages of cyanobacteria compose the modern stromatolites of Alchichica, a different one for each tufa-type (i.e. spongy, columnar, flat crusty). Nitrogen fixation takes place in both free-floating and stromatolite-forming cyanobacteria. High UV radiation affects microorganisms as inferred from: a) a large difference in N-fixation rates of cyanobacteria exposed and protected from UV radiation, and b) the almost absent micro- and macroorganisms in the first meters of the water column. Modern stromatolites take us back to the first type of life present in the Earth. Through understanding how these organisms evolved in extreme environments and have a better idea of their ecology, will allow us to find potential sites for extant life in other moons and planets.

THE LAKES OF NEVADO DE TOLUCA: LOW TEMPERATURES, ACID- ITY AND STRONG UV EXPOSURE Javier Alcocer1 and Elva Escobar2 1 Laboratorio de Limnología, Proyecto de Conservación y Mejoramiento del Ambiente, UIICSE, FES Iztacala, UNAM. ; 2 Unidad Académica de Sistemas Oceanográﬁcos y Costeros. Instituto de Ciencias del Mar y Limnología, UNAM.

Lago del Sol and Lago de la Luna are located inside the crater of the Nevado de Toluca volcano (19 ◦06N, 99 ◦45W), in Central Mexico. The two lakes are positioned above the timberline (i.e. 4,200 m above sea level), and are characteristic of alpine or high-altitude lakes. The lakes are shallow (zmax =15mand10m,mean depth = 6 m and 5 m, respectively). The water of the lakes is cold, transparent, acid and poorly mineralized. A cold, humid climate characterizes the area. The annual ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 503 temperature ﬂuctuates between 2 and 12 ◦C, with large circadian variation and the annual precipitation ranges from 1,200 to 2,000 mm; the average annual evaporation is 990 mm. Aquatic biota is mostly found associated to vegetation and the presence of red-colored organisms (i.e. imparted by pigments such as caratenoids), that suggest protection mechanisms from the UV radiation in high altitudes. Low temperatures, acidity and high UV exposure are faced by the biota of these lakes. If such conditions are to be found elsewhere in other planets, it is likely that a similar life-type evolved.

THE MAARS OF VALLE DE SANTIAGO: HYPERSALINE AND HIGHLY ALKALINE Javier Alcocer1 and Elva Escobar2 1 Laboratorio de Limnología, Proyecto de Conservación y Mejoramiento del Ambiente, UIICSE, FES Iztacala, UNAM. ; 2 Unidad Académica de Sistemas Oceanográﬁcos y Costeros. Instituto de Ciencias del Mar y Limnología, UNAM.

The Valle de Santiago maar lakes are located in the southern portion of the Guana- juato state. Rincón de Parangueo is located at 20 ◦25N, 101 ◦15W and 1,700 m above sea level, and La Alberca at 20 ◦23N, 101 ◦12W and 1,690 m above sea level. These lakes have been exposed to extraction for irrigation, high evaporation and diminished water input. The shape of the lakes ﬂuctuates from being circular to elliptical with “initial” surface area between 0.15 and 0.69 km2. The lakes hold saline(TDSupto120gL−1), alkaline (pH 9.5–9.8) water, dominated by sodium- magnesium and carbonate-bicarbonate ions but also high quantities of sulfate and chloride are present. The region’s annual average temperature ranges between 18 and 20 ◦C and the annual average precipitation is between 600 and 800 mm. Valle de Santiago is located on the northern margin of the tropical summer rain-belt, the arid frontier of Mesoamerica. The negative water budget led to hypersaline, soda- alkaline water bodies. La Alberca shows purple color water revealing the large concentrations of purple sulfur bacteria (Thiospirillum-like bacteria). In Rincón de Parangueo Dunaliella-like algae, tolerant to high temperature, salinity and UV radiation, are abundant. These extreme habitats help us to understand potential life forms to be expected in the solar system.

TROPICAL ANDEAN ECOSYSTEMS AS MODELS FOR EXTRASOLAR AND SOLAR PLANETARY HABITATS Marcano, V.1, Matheus, P.1, Balza, A.1,Durán,F.1, Campins, J.1, Navarro-Gonzalez, R.2, McKay, C.3, Davila, D.1,Davis,W.4 and Palacios-Prü, E.1 1 Laboratorio de Biología y Química Evolutiva, Centro de Microscopía Electrónica, Universidad de Los Andes, P. O. Box 163, Mérida, Venezuela; 2 Laboratorio de Química de Plasma y Estudios Planetarios, Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, México D.F, México; 3 Space Science Division, NASA Ames Research Center, Moffet Field, CA 94035 USA; 504 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

4SETI Institute-Space Science Div., NASA Ames Research Center, Moffet Field, CA 94035 USA

Surface and subsurface biota in the Andean high mountain are near the limits of photoautotrophic and chemolithotrophic life in tropical region. Therefore, the relationship between N2,O2,andCO2 partial pressures, nitrogen fixation at soils, chlorophyll content, biological productivity (/max), and surface and subsurface thermal variation at the Andean high mountain was evaluated to determine the main factors affecting the growth of organisms living in this region. Climatic data were obtained from 9 meteorological stations placed between 2,448 and 4,772 m at the Sierra Nevada de Mérida, Venezuela. These data were related to the metabolic activity (viz. ammonification, nitrification and CO2 assimilation) investigated in several vascular plants and in soil microorganisms. The obtained results suggest that the lower development of the plants correlated to the altitude could be a direct consequence of the low O2 and CO2 levels recorded in the higher altitudes, which reduce the photosynthetic activity, biological productivity, and the production of − NO3 at the soils. Hence, chlorophyll content was inversely correlated to the in- crement of the altitude (2.3 x 10−2 mg Chl (a+b) g−1 dry weight m−1).Even chemolithotrophic bacteria cannot carry out the fixation process by nitrification at the snow zone (> 4,700 m) because this process require aerobic conditions while the high concentrations of NH3found in the snow zone correspond to the anaerobic nature of bacterial ammonification. Extrapolating the obtained data to an exobiological context it is suggested that extrasolar or solar environments with aPO2 probably < 125 mbar should be excluded on the occurrence of complex photosynthesis-based life forms due to the aerobic feature of bacterial nitrification. − Altitudinal distribution of mean NO3 values revealed the existence of a “critical nitrogen-fixing zone” localized at timberline (∼ 3,250 m). This parameter could be utilized to define the critical nitrogen-fixing boundary in the habitable zone (HZ). Minimum PCO2suitable for the occurrence of C3-like advanced photosynthesis- based life forms in these bodies should have values ≥ 17 x 10−2 mbar corresponding to a mean temperature ≥ 277 K and to a biological productivity rate /max ∼ 0.27 whereas that minimum PCO2suitable for the occurrence of C4- like advanced photosynthesis-based life forms in those environments should not exceed values ∼ 14x10−2 mbar. Further, a timberline-like critical photosynthetic boundary was defined for latitudes near 0 ◦ from Earth-like planets having a mean ◦ −2 surface temperature of ∼ 11 C, /max ∼ 0.64, and a PCO2of ∼ 21 x 10 − mbar. On the other hand, high concentrations of atmospheric N2 and NO3 at soils from extrasolar or solar bodies placed in the HZ are not necessarily diagnostic features of life able to fix atmospheric N2 by ammonification and nitrification. The former process require of H2O whereas the later process require the presence of O2and probably of a PO2 > 125 mbar to maintain complex photosynthesis-based life. However, reactions between N2 and H2O in the atmosphere surrounding lightning discharges can provide an important source of NH3 and NOx even when O2 is ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 505 a minor atmospheric constituent, and therefore could allow the availability of fixed nitrogen for the evolution of life on Earth-like planets.

TROPICAL EXTREMOPHILES AS MODELS FOR ANCIENT AND FU- TURE LIFE ON VENUS Marcano, V., Miranda-Contreras, L., Benitez, P., Matheus, P., Palacios-Prü, E. Laboratory of Evolutionary Biology and Chemistry, Electron Microscopy Center, University of the Andes, P. O. Box 163, Mérida, Venezuela. [email protected]

The existence of acidic and hot or saline oceans on early Venus may have favored the successful appearance and transfer of life during the first hundred million years (Cockell, 1999). On the other hand, there are a variety of alternatives for terraforming Venus (Adelman, 1982; Fogg, 1987; Birch, 1991). One of these alternatives could be the implantation of a pioneering biosphere on Venus in scalding hypersaline or acidic oceans (Gillett, 1985; Fogg, 1987), created by a global “Big Rain” as the planet cooled. The most expected organisms able to grow in these primeval or future environments are: first, lithoautotrophic, obtaining energy by oxidizing H2S; second, photoautotroph, able to generate oxygen in rich sulfur environments, and third, halophilic, growing in saline concentrations > 2 M NaCl. This work describes three experimental models based on the study of tropical extremophiles that lives either in solfataric hydrothermal environments between 35–45 ◦CatpH 5-6 (i.e. Beggiatoa, Thiothrix, Oscillatoria, Anacystis) or in saline environments between 0.2 M and ≥ 5.5 M NaCl, between 30-40 ◦C (i.e. Amorphoteca resinae). All the utilized species come from the Venezuelan Andes, between 1,600–2,100 m. Nitrogen fixation, dissolved oxygen, chlorophyll content, pH, conductivity, ion concentration, and hydrothermal variation were evaluated to know the main factors affecting the growth of these organisms and to calculate the amount of free energy consumed. Additionally, electron microscopy analysis (TEM) was carried out. Hy- drothermal values were higher during the rainy period (≤ 45 ◦C) than during the dry period (∼ 35 ◦C). Beggiatoa and Thiothrix metabolized reduced sulphur by the following reactions which were temperature dependent:

2H2S+O2 → 2S+2H2O (1) G ◦ (35 ◦C) = –9.370 kcal mol−1; G ◦ (45 ◦C) = -9.834 kcal mol−1

→ −2 + 2S+2H2O+3O2 2SO4 +4H (2) G ◦ (35 ◦C) = - 192.86 kcal mol−1; G ◦ (45 ◦C) = - 199.123 kcal mol−1

These species accumulate sulfur globules in their cells as a result of H2S oxidation. In the absence of H2S, this sulfur serves as a electron donor for metabolism −2 and is oxidized to sulfate. The SO4 and S amounts recorded, assumed as biogenic, have variable concentrations during both periods. G ◦ values for these reactions 506 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 for both periods are near the minimum that may support bacterial metabolism, viz. 10–15 kJ mol−1. Cyanobacterial populations of Oscillatoria growninthese thermal waters showed a low photosynthetic rate during the dry period, as reflec- ted by the chlorophyll (a) content (i.e. dry period, 1.69 x 10−3 mg Chl−1 mg−1 d. wt.; rainy period, 2.14 x 10−3 mg Chl−1 mg−1 d. wt.). Cultures of Anacystis exhibited a higher number of cells and Chl (a) content in temperatures ≥ 40 ◦C than in lower temperatures. The G ◦ values for nitrogen fixation reactions were also temperature dependent. On the other hand, although A. resinae can produce a higher amount of proteins (up to 0.45 mg total protein g w. wt.−1) and biomass (3.84 x 10−3 µg µl−1 h−24) between 1.8-2.2 M NaCl (roughly three to four times higher than the saline oceanic concentration), the protein amounts and biomass produced in concentrations ≥ 5.5 M NaCl (≥ 20%) were still significant (i.e. 0.3 mg total protein g w. wt.−1;3.28x10−3 µg µl−1 h−24). However, in absence of NaCl no growth was observed. These tolerated saline concentrations are similar or higher to those of the Great Salt Lake or Dead Sea. Oceans on early or terraformed Venus could have similar compositions to those media where grown these species.

References

Adelman, S. J.: 1982, Can Venus be terraformed into an Earth-like planet?, JBIS 35, 3–8. Birch, P.: 1991, Terraforming Venus quickly, JBIS 44, 157–167. Cockell, C. S.: 1999, Life on Venus, Planetary and Space Science 47, 1487–1501. Fogg, M. J.: 1987, The terraforming Venus, JBIS 40, 551–564. Gillett, S. L.: 1985, The postdiluvian world, Analog CV(11), 40–58.

MICROBIAL LIFE AND TEMPERATURE: A SEMI EMPIRICAL APPROACH León Garzón Energy department, University Independencia, 13, E-33004 Oviedo (Spain)

The effect of temperature on survival of microorganisms has been examined. Sev- eral models have been developed but none of them is appropriate for this study. We have proved that the equation given below, deduced from the Theory of Rate Process (Glasstone et al., 1941), improves the inadequate Arrhenius equation that in spite of this is being nowadays used. The equation is: k=(kBT/h) exp (-G*/RT) −1 s (1), where k is the rate and kB ,h, T, Rhave the usual meaning. G* is the free energy of activation for the envisaged process. The excellent standard deviation values obtained from (1) show that the equation (1) is much more suitable that the old Arrhenius equation. Fortunately the Glasstone equation is a very appropriate and simple tool to achieve a better understanding of the involved phenomena. Equation (1) shows the inﬂuence of temperature upon life survival. So, according to such an expression, life survival would be much more prolonged at low ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 507 temperatures than at moderate ordinary ones. Discoveries of microorganisms in Siberian permafrost samples that are several million years old, in deep oil ﬁelds, mines and other extreme habitats seem to be consistent with the equation (1). Sev- eral examples have quantitatively been studied. So, spore enhanced resistance to extreme temperatures can be easily explained in terms of its high G* value. Other implications on food sterilization practices and on exobiology have also been discussed by means of the above-mentioned equation.

References

Clark, B. C.: 1999, Origin of Life Evol. Biosphere 291, 521–545. Gilichinsky, D.: 2000, Permafrost frontieres of life, 12émes Rencontres de Blois. Abstracts, 24, Blois, France. Glasstone et al.: 1941, The Theory of Rate Processes,McGraw,NY.

ISOTOPIC TRENDS ON RECENT CARBONATE STROMATOLITES FROM CUATRO CIÉNEGAS, COAHUILA E. Cienfuegos1, Francisco J. Otero1, P. Morales1, M. Rohmer2 and E. Chacón1 1 Departamento de Geoquímica, Instituto de Geología, UNAM, Circuito de la Investigación Cientíﬁca, Ciudad Universitaria, México D. F., 04510; 2 Laboratorie de Chimie et Biochemie des Microorgan- isms, Institut Le Bel, Universite Louis Pasteur – 4rue Blaise Pascal, F-67070 Strasbourg Cedex, France

In the Valley of Cuatro Cienegas, in the locality of Sierra La Madera, which is a small area within the Sierra Madre Oriental, several marshes with conspicuous recent microbialithes develop as result of the inundation patterns and precipitation rates. These reef-like microbialithes appear to form near the sediment-water interface, and occur as prominent calcareous dome-shaped stromatolites, composed among other microorganisms, by microbial mats of in situ calcifying cyanobacteria. Macrostructure of these intertidal microbialithes varies among nodu- lar, columnar, cylindrical and dome morphologies, which can be found in groups as irregular micro-columns, smooth and bulbous micro-columns and weakly-laminated crusts, or isolated, exhibiting a recumbent altitude with a low-relief rugged surface and a µm to mm-sized thickness of laminae. In the upper layers of these stromatolites, several populations of predominantly cyanobacteria, diatoms, green algae and anoxygenic bacteria occur. The most conspicuous head-shaped microbialithes are between 95 and 70 cm in height and between 80 and 1.20 m wide, where dark-green biofilms fringing the stromatolitic heads immediately at the lake level are ranging from 500 µmupto1,000µm in thickness. Diatoms abundance further increases in submerged areas. Microstructures of the lithified micritic layers result from the constant dynamics of the several types of metabolisms involved that determine the fluctuation on the pH, CO2 and O2 gradients. Small-scale variations reflect the relief where protruding stromatolites are subject to degradation by ra- 508 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 diating microborings of cyanobacteria. Carbonate was removed by treatment with dilute hydrochloric acid. After decalcification, the upper crusts of these lithified stromatolites shows a large amount of residual organic material. The samples were extracted with organic solvents and the resulting extracts were evaporated for mass- spectrometry analysis. Preliminary isotopic data shows δC13 PDB values between 0.43 and 0.57 signifying an organic C source, predominantly from cyanobacteria, and δ018 PDB from –7.38 to –3.69, which are consistent with ranges described from continental carbonates. The input of organic matter derives from benthic organisms as microbial communities and algae, from the water columns, as zooplankton, higher plants and phytoplankton, early postsedimentary chemical and microbial alteration as the degradation of primary lipids and bacterial lipids.

CARBON ISOTOPIC VARIATION OF RECENT MICROBIAL MATS DE- VELOPED AT SULFUROUS SPRINGS Morales-Puente, P.2, E. Cienfuegos, M. Sánchez-Ramos1, D. Fragoso T.3 and E. Chacón B. 1 Departamento de Geoquímica, Instituto de Geología, UNAM, Circuito de la Investigación Cientíﬁca, Ciudad Universitaria, México D. F., 04510; 2 Facultad de Ciencias Naturales, Universidad Autónoma de Querétaro, México; 3 Departamento de Ficología, Facultad de Ciencias, UNAM, Circuito Exter- ior, Ciudad Universitaria, México D. F., 04510

Sulfurous springs harbor a great abundance of modern microbial mats developing around hot sulfurous springs in several active sites of the area of LoS Azufres, Microhacan, Mexico. This locality lies within the Neovolcanic Eje at Central Mex- ico and has been active since the Recent. Microbial mats are mainly developing at the water-sediment interface, showing a well-deﬁned distribution along a temperature gradient. Some of the most abundant microbiota includes ﬁlamentous LPP-cyanobacteria and coccoid Chroccocus cyanobacteria. Other abundant and diverse component are pennate diatoms aligned within these mats. Although mi- crostructure development is incipient along the temperature gradient, it shows a regular orientation. The aim of this work was the description and analysis of the C-isotopic values along this gradient. This work has been supported by CONACYT (G 35442 T).

MICROBIALITHES FROM A HIGHLY SALINE CRATER LAKE IN RINCON DE PARANGUEO, MEXICO Malda, J.1, López-Sauceda, J.1, Morales-Puente, P.2, E. Cienfuegos2, Sánchez- Ramos, M.1 and Elizabeth Chacón B. 1 Facultad de Ciencias Naturales, Universidad Autónoma de Querétaro, México; 2 Departamento de Geoquímica, Instituto de Geología, UNAM, Circuito de la Investigación Cientíﬁca, Ciudad Uni- versitaria, México D. F., 04510 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 509

The search for microbial life, fossil and extraterrestrial, is one of the most exciting challenges in Astrobiology. During the last years the search for microbial communities thriving under extreme environments have been discovered and studied using different approaches. Here we describe some recently discovered microbialithes that inhabit and develop under harsh environmental conditions that are though to have been present during Precambrian times and therefore represent modern analogues of early life on Earth. Microbialithes from a highly saline crater lake were investigated at the locality of Rincon de Parangueo, (between the 20◦ and 101◦) Guanajuato, Mexico. This volcaniclastic sedimentary crater, of quatern- ary age, is a depression of approximately 50 km in diameter, where the external facies are characterized by coarse-grained sediments that show extensive deposits of silica. It harbors not only ephemeral microbial mats developing at the water- sediment interfase and as surficial crusts floating on the lake. Small dome-shaped stromatolites of NaCO3 can be found at the former margins of this crater, occurring as dome-shaped stromatolites of 10 cm in length and 5 cm in height, showing a clotted and coarse microfabric at the base and a finely-laminated microfabric at the top. The chemical analysis of such microbial ecosystem represents a world-wide unique habitat that could serve as an experimental model of early life around the Earth ocean during Precambrian times, and is a powerful tool that can be used, not only to infer past microbial life, but also to detect and identify life elsewhere. This work has been supported by CONACYT (G 35442 T) and by the CON- CYTEQ. 510 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 511

FOSSIL RECORD 512 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

LASER RAMAN SPECTROSCOPIC ANALYSIS OF BIOCHEMICAL CHANGES CAUSED BY FOSSILIZATION Andrew D. Czaja1, J. William Schopf1, Michael C. Storrie-Lombardi2, Anatoliy B. Kudryavtsev3and Rohit Bhartia2 1 Department of Earth & Space Sciences, and Institute of Geophysics & Planetary Physics (Center for the Study of the Evolution and Origin of Life), University of California, Los Angeles, CA 90095- 1567, USA; 2 Center for Life Detection, NASA Jet Propulsion Laboratory, Pasadena, CA 91109, USA; 3 Astro and Solar System Physics Program, Department of Physics, University of Alabama at Birmingham, Birmingham, AL 35294-1170, USA.

During diagenesis and fossilization, the organic constituents of living systems are degraded and geochemically altered. Understanding how such constituents change over time would allow us to extrapolate, from fossil evidence, aspects of the original biochemistry. Toward this end, we are using several techniques to fully characterize the organic chemical composition of a modern fern species (Dennstaedtia cicutaria)and a well preserved fossil analogue (Dennstaedtiopsis aerenchymata) petrified in the Eocene Clarno Chert of Oregon (USA). Both UV- and visible light-Laser Raman spectroscopy (LRS) studies are ongon- ing at the NASA Jet Propulsion Laboratory in Pasadena, CA, and at the University of Alabama, Birmingham, respectively. Raman spectra of the visibly distinct tissues of these plant axes show evident differences among the various tissues and also between the modern and fossil specimens – the former reflecting biochemical differences; the latter, changes caused by fossilization. Also ongoing are a series of heating experiments, using the modern ferns, to simulate the degradation caused by geological processes. Samples are being heated under anoxic conditions to different stages of degradation, producing a gradient of artificial ‘fossils’ from modern to the level of fossilization seen in the Eocene specimens, and analyzed with LRS to better understand the natural changes in biochemistry through time. In collaboration with the Carnegie Institution, Washington D.C., we are analyz- ing both the modern and fossil ferns with solid state Nuclear Magnetic Resonance (NMR) Spectroscopy to precisely and quantitatively determine the organic functional groups contained in each, helping us interpret the spectra produced by the different Raman systems. Similarly, in collaboration with the University of Texas, Austin, we are using Transmission Electron Microscopy (TEM) to characterize the cell wall morphology of both the modern and fossil ferns at the molecular level, allowing us to relate this structure to the biochemical characteristics determined using NMR and LRS. ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 513

AN ANCIENT MICROBIAL ECOSYSTEM: PRECAMBRIAN ANALOG OF LIFE IN THE COSMOS Leigh Anne Smith and William Schopf1 Department of Earth and Space Science, Unuversity of California, Los Angeles, USA

The study presented here focuses on the recently discovered, but as yet almost entirely undescribed ∼850-Ma-old (Neoproterozoic) microbial community petrified in carbon-rich cherts of the Bambuí Group of south-central Brazil, “the best preserved and most diverse Precambrian microbiota known from South Amer- ica. . . [Important because it] includes the most varied assemblage of fossil fila- mentous bacteria now known from the geologic record, worldwide” (Fairchild et al., 1996, Precambrian Res. 80:125-152). This fossil biocoenose contains a wide variety of cyanobacterial and noncyanobacterial prokaryotes, the investigation of which will lead to increased understanding of the fields of Precambrian paleontology and microbial evolution. Following the completion of traditional morphology-based study, my work will center on use of two new techniques for chemical analysis of individual microscopic fossils– laser-Raman spectroscopy of their molecular makeup and ion mi- croprobe mass spectrometry of their elemental and isotopic compositions. Atten- tion will be focused on whatever vestiges of original biochemistry are preserved in these microfossils. Attempting to correlate cellular morphology with chemical composition, my ultimate goal is to elucidate the physiological characteristics of the major biotic components and the carbon and energy flow of this ancient ecosystem. Understanding the metabolic characteristics of these fossil microbes will help to reconstruct the ecology and evolution of early life on Earth and may eventually lead to an understanding of such systems on other worlds. 514 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 515

PHILOSOPHICAL, HISTORICAL AND EDUCATIONAL ASPECTS 516 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

EARLY SPANISH SCIENTIFIC WRITINGS ON THE ORIGIN OF LIFE Jesús I. Catalá1 and Juli G. Peretó2 1 Institut d’Història de la Ciència i Documentació “López Piñero” (Universitat de València-CSIC) and 2 Departament de Bioquímica i Biologia Molecular, Facultat de Ciències Biològiques, Uni- versitat de València

A few years after the publication of Darwin’s Origin of Species (1859), the political and social atmosphere in Spain was receptive to the new ideas of evolution of life by natural selection. After the revolution of 1868, discussions on the evolution of life and the origin of man were at the centre of many public debates in an ideo- logical and religious context more than as an academic issue. Albeit in 1874 the monarchic restoration frustrated the climate of intellectual freedom still there were significant scientific events. In 1877 appeared the first Spanish version of the Origin of Species and Peregrin Casanova (1849–1919), a professor of Human Anatomy at the University of València, published La biología general. Throughout this 412- pages book Casanova introduces an orthodox Haeckelian vision of the origin and evolution of life. Furthermore Casanova translated some works by Haeckel, wrote the foreword of the Spanish version of Die Perigenesis der Plastidule. . . (València 1882), and organized the homage to Darwin at the University of València in 1909. At the beginning of XX century teachers, naturalists and professors adopted two main positions about the origin of life: (i) Accepting Pasteur’s experimental suc- cess against the spontaneous generation doctrine, early life should appear on Earth by a supernatural cause. Thus Jaume Pujiula, S.J. (1869–1958), a Catholic priest and influent biologist, accepted the evolution of species but invoked a Creator for the origin of life and humans (see his collected lectures La vida y su evolución filogenética, Barcelona 1915). (ii) However a materialistic emergence of life was admitted by experimental scientists like colloidal chemist A. de Gregorio Rocaso- lano (1873–1941) in despite of his conspicuous Catholicism. In his book Estudios químico físicos sobre la materia viva (Zaragoza 1917) we clearly see the influence of authors like Stephan Leduc, Jacques Loeb or the Mexican plasmogenist Alfonso L. Herrera.

PHILOSOPHICAL FOUNDATIONS OF THE THEORIES ON THE ORI- GIN OF LIFE Wlodzimierz Lugowski Institute of Philosophy and Sociology, Polish Academy of Sciences, PL-00-330 Warsaw, Nowy Swiat 72, e-mail: wlugowsk@iﬁspan.waw.pl

More than one hundred theories of the origin of life published during last thirty years has been identified and analysed, their hidden ontological and epistemological assumptions compared with the explicit philosophical statements made by occasions by their authors [1]. All the current theories has been classified according the mode of explanation of the transition ”non-life into life”, i.e. the driving force ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 517 of the prebiotic evolution. The differences between the theories, however, as well as the current controversies in the scientific community will be shown to be dependent of several much more profound methodological assumptions underlying the origins of life studies. What makes protobiology perhaps more attractive from the philosophical point of view than even biology itself, is its deep internal tension caused by the duality of its methodological roots. As it will be shown, protobiology namely is born both from the spirit of the Hegelian and the Comte’an metaphysics. And in spite of several declarations by scientists that it is possible – and needed – to be free of metaphysics (especially of the former kind) we will end up with the conclusion that the question can not be how to reject one of them but should instead be how one can stay conscious of both [2]. Only by keeping in mind such a double theoretical genealogy of the origin of life studies it is possible to avoid several paradoxes (information without information, order without order, etc.), commonly claimed to be inherent to all theories except ones own.

References

Lugowski W.: 1995, Filozoﬁczne podstawy protobiologii, Warszawa (Philosophical foundations of protobiology). Lugowski W.: 1998, In venenoso Dracone summam medicinam inesse, or on the mythology and philosophy of biology, in: W. Lugowski, K. Matsuno (eds.), Uroboros, or biology between mythology and philosophy, Wroclaw, pp. 5–26.

HISTORICAL EVOLUTION OF SCIENTIFIC IDEAS ABOUT THE ORI- GIN OF LIFE AND ITS RELATIONSHIP WITH STUDENTS’ PREVIOUS IDEAS Valladares, L.([email protected]) y Gallegos, L. Unidad de Pedagogía Cognitiva y Aprendizaje de la Ciencia, CCADET, UNAM, Circuito Exterior, Ciudad Universitaria, C.P. 04510, México

This work presents a historical, conceptual and epistemological analysis of sci- entiﬁc ideas for the origin of life as a tool for interpreting students’ previous ideas on this topic. Three main points entails the historical ideas with high school students’ previous ideas reported within the research literature. They correspond to principal approaches that historically have explained the origin of life: spontaneous generation, creation, and Oparin-Haldane’s evolutionary hypothesis. Conceptual analysis of these historical approaches allows the characterization of high-school students thought, and it also offers recognition of distinct ontological categories involved in the historical process as well as in the students’ ideas: the creationist and the evolutionary. 518 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

Characterization and interpretation of biological world that emerges as possible under each ontological category possesses different attributes because con- ceptualizations defining each category are distinct too. The shift of a conceptual entity initially belonging to a category into a different one, constitutes a radical conceptual change, which is different in nature from the shift in the concept’s categorical status within an ontological categogory. They both constituted conceptual changes of distinct nature in the history of scientific ideas as well as in students’ ideas about the origin of life. Three conceptual changes involved in the historical development of scientific ideas for the origin of life are considered as a result of epistemological recon- structions. One of them –a radical decided the critical crossing of the creationist ontological category to the evolutionary one. The importance of this discovery is that these same conceptual changes might also appear in individual students, an issue that might have educational implications.

GETTING THE FEELING OF TIME IN ORIGIN AND EVOLUTION OF LIFE EXHIBITIONS F.G. Mosqueira1,S.Ramos-Bernal2 and A. Negrón-Mendoza2 1 Dirección General de Divulgación de la Ciencia, UNAM. Cd. Universitaria, A.p. 70-487, 04510 México, D.F. México; 2 Instituto de Ciencias Nucleares, UNAM. Cd. Universitaria, A.p. 70-543, 04510 México, D.F. México

It seems to be a difficult task to give to the public (and the experts) an idea for times elapsed for different events of the geological and biological history of the Earth. Such figures are rounding billions of years. In this perspective we propose an exhibit -suitable for a science museum- to deal with this situation. The objective of the exhibit would be to give a perception of elapsed time in the history of the Earth not so much in absolute terms, but in proportional terms. To that end we envisage to represent time as a distance (let say 20 m) and take the visitor through a journey from the origin of the Earth to nowadays, in a pictorial tunnel showing typical views of the Earth in accordance to the time trip. The public may travel in a carriages accommodating several people and travelling to a constant velocity, as for example 2 m/minute, i.e., 0.0332 m/s. In such trip, 1 m would represent 225 million years (if we assume the age of the Earth to be 4.5 x 109 years) and 7.5 million years of Earth’s history would have elapsed in 1 s of such trip. Several landmarks in the life history in the Earth may be marked in the tunnel. As for example, it may be spotted, at around 14 % of elapsed time after Earth’s origin, indirect evidence for unicellular life (the origin of life on Earth); at 22 %, fossil evidence for unicellular life (prokaryotic); at 60 %, fossil evidence for eukaryotic unicellular life; and at 87 %, we finally find fossils evidence for multi-cellular organisms for the first time. Such exhibit may be helpful to the public to get an idea of the proportions of time intervening in the origin and evolution of life on Earth. This is currently a pro- ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 519 posal to Universum, the Science Museum of the National Autonomous University of Mexico.

A PICTORIAL HISTORY OF ISSOL Mohindra S. Chadha1 and Sara E. Acevedo2 FormerDirector, Biochemical Group BARC, C-6 Beach House, Gandhigram Road, Juhu, Mumbai – 400 049 India; 2 SETI Institute, 2035 Landings Drive, Mt. View CA 94043 USA

The plans and progress for a history of the ﬁrst 30 years of ISSOL will be presented. The compilation, once complete, will include items such as • Photos, documents, and information related to the discussions leading up to the founding of the Society. • Historical reminiscences from long-time members. • Documents and photos from every triennial meeting from Pont a Mousson (1970) through Oaxaca, Mexico (2002). • An archive of PDFs of all issues of the newsletters. • Photos and brief biographies of all ISSOL Awardees. • Membership statistics over time. • Cumulative information about Executive Council Members. • Ofﬁcial Society records and documents. It is planned that the CD-ROM will be available for sale to members in the coming year, with proceeds going into the ISSOL treasury. A preliminary CD will be available for viewing. 520 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 521

EXTRATERRESTRIAL ORGANIC COMPOUNDS 522 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

SHOCK PROCESSING OF ICES IN PROTOPLANETARY DISKS George E. Hassel, Wayne G. Roberge, Douglas C. B. Whittet and Sachindev S. Shenoy New York Center for Studies on the Origins of Life, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 1218, http://www.origins.rpi.edu, e-mail: [email protected]

The water ice mantles on interstellar grains trap volatile molecules, such as CO and CH3OH, with an efﬁciency that depends on the amorphous or crystalline structure of the ice. The ice structure therefore affects the composition of comets formed from the icy grains. We are studying the processing of mantled grains by shock waves in protoplanetary disks The grains suffer a sudden increase in temperature, which can evaporate the mantles. This is followed by an extended cooling time during which the mantles recondense on timescales comparable to the crystallization timescale for hydrodynamic parameters consistent with the Jupiter-Saturn region of the solar neb- ula. Also, the shocks elevate the gas temperature, which may signiﬁcantly change chemical abundances in the vapor. We are comparing our results to observations of the composition of comets. The crystallization of ice and the exclusion of volatiles from the matrix may explain the volatile- depleted composition observed recently in Comet C/1999 S4(LINEAR), an Oort- cloud comet originating from the Jupiter- Saturn region. From the gas phase results, we study the HDO abundance relative to H2O to evaluate the possibility of delivery of cometary material to the early Earth by Jupiter-zone comets.

GRAIN GROWTH IN TAURUS MOLECULAR CLOUD Sachindev S. Shenoy, Douglas C. B. Whittet, Wayne G. Roberge & George E. Hassel Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, 110 8th St, Science Center, Troy, NY 12180 USA

Observations of outflows in a molecular cloud have been associated with far infrared sources suggesting ongoing star formation and existence of circumstellar disks. The dust grains, which get incorporated into these disks, have evolved in the molecular cloud and it is crucial to understand the properties of these dust grains, as they are the precursor to planet formation. Growth mechanisms are important as they change the size distribution and optical properties of the dust grains. It is known that coagulation and mantle formation occur in the dense environment of a molecular cloud, but no systematic study has been undertaken to see if there exists a correlation between these two growth processes. The observational signature of the two growth processes is quite distinct and can be parameterized to understand grain growth. To achieve this goal we focus on the Taurus Molecular Cloud (hereafter TMC) complex. We have surveyed the TMC region using the 2MASS database to selec- ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 523 ted highly reddened field stars and we have obtained visual photometric data for these objects. Using these two datasets we have constructed the visual to infrared extinction curve along the line of sight and have used the CCM (Cardelli, Clayton & Mathis 1989) law to evaluate the ratio of total to selective extinction. We propose to do spectroscopic observation in the 3.1 mm H2O ice band to investigate grain mantle growth as a function of optical depth in the TMC. We are also investigating the IUE database to construct an extinction curve covering IR, Visual and UV wavelength range. The UV extinction curve will help us in constraining the population of small grains along the line of sight. This study will be a first step towards understanding the importance of the two grain growth mechanism in a molecular cloud. There are only a few stars, which have extinction information, and 3.1 mm H2O ice data. This study will increase the dataset for which these two types of information are available and help in constraining two different growth models.

POSSIBILITY OF DETECTION OF GLYCINE WITH 50-M LARGE MIL- LIMETER TELESCOPE IN MEXICO Berezhnoi, A.A.1, Gonzalez, L.2, Sandoval, L.2 and Palma, A.1,2 1 Instituto Nacional de Astrofísica, Optica y Electrónica, Apartado Postal 51 y 216, 72000 Puebla, México; 2 Benemerita Universidad Autonoma de Puebla, Apartado Postal J-48, 72570 Puebla, México

The study of pre-biotic molecules like sugars and amino acids in outer space is a very important subject in the ﬁeld of origin of life. Glycine (NH2CH2COOH) is one of the simplest amino acids. Search for glycine in solar type protostar IRAS 16293-242 (Ceccarelli et al., 2000) and in TMC-1 (Dickens et al., 2001) gave upper limit for glycine abundance as low as 10−10 and 3*10−10 respectively. But future observations of molecular clouds and protostars with 50-m LMT can give more information about glycine abundance in space in comparison with 30-m IRAM telescope. Rotational spectrum of glycine is calculated. Our theoretical results are in agreement with laboratory spectral data (Lovas et al., 1995). The most perspective glycine lines for search in objects with temperatures from 20 to 150 K are proposed.

NOBLE GASES IN COMETS AND THE ORIGIN OF EARTH’S VOLAT- ILES Humberto Campins University of Arizona

Recent results on the chemical composition of comets have stimulated several hypotheses on the origin of Earth’s volatiles, including water, organics and noble gases. It has been suggested (e.g., Owen and Bar-Nun 1995, 2001; Delsemme 1998, 524 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

2000) that comets are the main source of Earth’s water and organic molecules. On the other hand, the Argon abundance observed in Comet Hale-Bopp has prompted Swinlde and Kring (2001) to argue that comets are unlikely to be a signiﬁcant source of terrestrial volatiles. Who is right? The surprising composition of Comet Linear (1999 S4) provides new clues relevant to this issue.

OBSERVATIONS OF HCN, HNC AND NS IN COMET C/2000 WM1 (LIN- EAR) William M. Irvine1, Douglas McGonagle1, Henry Matthews, Herzberg2,Albert Nummelin3 and Toby Owen4 1 Dept. of Astronomy, University of Massachusetts, USA; 2 Institute of Astrophysics, National Re- search Council of Canada, and Joint Astronomy Centre, Hilo, Hawaii, USA; 3 Dept. of Electrical and Computer Engineering, Chalmers Lindholmen University College, Sweden; 4 Institute for Astronomy, University of Hawaii, USA

Current theories of the chemical nature of the early terrestrial atmosphere suggest that it may have not been sufﬁciently reducing for the easy production of the basic building blocks of biologically important monomers such as amino acids, sugars and nitrogenous bases. Increasing attention is thus being given to the input of exogenous organic material from carbonaceous meteorites, comets and interplanetary dust particles. As the most volatile-rich among such sources, comets are particularly important. Observations over the last few years have shown that comets contain a complex, very non-equilibrium mixture of both organic and inorganic volatiles that are potential reactants in prebiotic chemical evolution. Interestingly, both the chemical composition and the large hydrogen isotopic fractionation are quite similar to what is observed in interstellar molecular clouds, the birthplaces of stars and planets, implying that some cometary organics may actually be of interstellar origin. Among the observed species hydrogen cyanide, HCN, is of particular importance for prebiotic chemistry. The reactive species HNC and NS are also observed in comets and might be expected to play roles in such processes. We report here on observations of HCN, its isomer HNC, and the NS radical in the recent comet, C/2000 WM1 (LINEAR). Observations were carried out at both the James Clerk Maxwell Telescope (JCMT) in Hawaii and at the Swedish-ESO Submillimetre Telescope (SEST) in Chile. Both HCN and HNC were detected, and a limit was set on the abundance of NS. The HNC/HCN abundance ratio appears to be of order 10%.

THE LARGE MILLIMETER TELESCOPE- GRAN TELESCOPIO MILI- METRICO William M. Irvine1, F. Peter Schloerb1, Alberto Carramiñana2 and Luis Carrasco2 1 Dept. of Astronomy, University of Massachusetts, USA; 2 Instituto Nacional de Astrofísica, Óptica y Electrónica, Mexico ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 525

The Large Millimeter Telescope/Gran Telescopio Milimetrico (LMT) project is a collaboration between the University of Massachusetts and the Instituto Nacional de Astroﬁsica, Óptica y Electrónica to build a 50 m diameter telescope that will have good efﬁciency at wavelengths as short as 1 mm. The LMT will have an overall effective surface accuracy of ∼70 micrometers and an ultimate pointing accuracy of better than 1 arcsec, and will thus be the largest millimeter wavelength telescope in the world. The LMT site is Sierra Negra in the state of Puebla, at 4,640 meters above sea level in Central Mexico. At 18◦59N latitude, it offers good sky coverage of both hemispheres. The normally low humidity will allow operation of the radio telescope at frequencies as high as 345 GHz. The LMT will make use of recent advances in structural design and active control of surface elements to achieve the required surface and pointing accuracy. The foundation at the site is now complete, the steel for the alidade has been fabric- ated and about half has been transported to the site, and the monitor and control system has been successfully tested on another telescope. The schedule calls for acceptance tests in late 2004. The initial complement of instruments will include a 32 element, heterodyne focal plane array at 3mm; a large format, focal plane bolometer array; a unique wide band receiver and spectrometer to determine the redshifts of primordial galaxies, and a 4 element receiver for the 1mm band. With its excellent sensitivity and angular resolution, the LMT/GTM will enable unique studies of the early universe and galaxy evolution, the interstellar medium and star formation in galaxies, and planetary science. In particular, it will be a powerful instrument for astrobiology, including studies of organic chemistry in comets and planetary atmospheres, and in molecular clouds in the Milky Way and other galaxies.

PREBIOTIC POLYMERIZATION PROCESSES IN INTERSTELLAR ME- DIUM G. Cocho1,A.Cruz1 and G. Martinez-Mekler2 1 Instituto De Fisica, Unam, Apdo Postal 20-364, 01000 Mexico Df Mexico; 2 Centro De Ciencias Fisicas, Unam, Apdo. Postal 48-3, Cuernavaca, Morelos, Mexico

The presence of a variety of organic compounds in the interstellar medium, comets and meteorites, as well as the evidence for life on Earth 3870 millions years ago, suggests a scenario where prebiotic and perhaps protobiotic process took place outside of the Earth. Polymerization processes have been proposed which could take place in the interstellar medium, with ultraviolet radiation as source of monomer activation and with long wave electromagnetic radiation forcing the activated monomers to oscillate, collide and form polymers [1,2,3,4]. These polymerization processes would occur in a network of channels on the surface of interstellar medium grains. Monomers would be fed at the extremes or from the interior of the grain channels. We have modeled both situations and found that under reason- able conditions the production of linear polymers is quite high in both cases. We 526 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 can consider the presence of monomers of two polarities or chiralities. If circularly polarized ultraviolet radiation destroys preferentially the monomers of one of the polarities or chiralities, eventually one should end with polymers with one of the polarities or chiralities. Such a scenario could be important for the origin of biological polymers.

References

J. M. Greenberg: 1996, Chirality in Interstellar Dust and in Comets: Life from the Dead Stars, in D.B. Cline (ed.), Physical Origin of Homochirality in Life, (AIP Proceedings, 379) pp. 185–210. G. Martínez-Mekler, M. Aldana, F. Cázarez-Bush, R. García-Pelayo and G. Cocho: 1999, Primitive Molecular Machine Scenario for the Origin of the Three Base Codon Composition, Origin of Life and Evolution of the Biosphere 29, 203–214. M. Aldana, F. Cázarez-Bush, G. Cocho and G. Martínez-Mekler: 1998, Primordial Synthesis Machines and the Origin of the Genetic Code, Physica A. 257, 119–127. G. Martínez-Mekler, M. Aldana and G. Cocho: 1999, On the Role of Molecular Machines in Origin of the Genetic Code. Statistical Mechanics of Biocomplexity, Proceedings of the XV Sitges Conference (lecture notes in physics, 527, 112–123), Springer-Verlag, Berlin.

RADIATION CHEMISTRY OF WATER IN CHEMICAL EVOLUTION EX- PLORATION I. G. Draganic1, A. Negron-Mendoza2 and S. I.Vujosevic1 1 Institute of Nuclear Sciences Vinca, Belgrade, P.O. Box 522, (Serbia)Yugoslavia; 2 Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Mexico D.F., Mexico

Some aspects of radiation chemistry of water (liquid, vapor, ice) of interest to the studies of chemical evolution processes are presented. Basic physical and chemical facts are given on the generation of free radicals, efﬁcient promoters of processes in conditions often considered hostile for prebiotic chemistry such as those in ocean depths and underground waters of our early planet, or in water ices in Space. The generation of oxygen and oxidizing chemical species in waters of early Earth, induced by radiations of potassium-40 in primitive oceans, or by mixed radiations of natural nuclear reactors in some underground waters, is presented in some details. Radiolysis of water vapor, neglected in radiation chemical approaches to primitive atmosphere, is considered. Various observations of radiation chemical behavior of water ice, the most abundant ice in the solar system, are surveyed. Attention is paid to radiation-induced chemistry in cometary ice as observed in laboratory simulation experiments. The results reviewed show that radiation-produced oxidizing chemical species, free radicals, oxygen and hydrogen peroxide, appear in the primitive hydrosphere in modest concentrations but are generated continuously, in a large water mass and ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 527 on a large geological time scale. They suggest a modest intrinsic oxidizing capacity of the early hydrosphere, a ﬁnding of interest to the studies of processes leading to earliest forms of living matter as well as those shaping the environment where oxygen-tolerant life forms evolved. About seventy molecules of interest to prebiotic chemistry are presently reported in radiation chemistry of water-dominated systems (liquid, solid, aqueous). Complementing the picture obtained by low energy radiations (ultraviolet, low energy charged particles), they stimulate further, systematic, research with energetic radiations.

THE LABORATORY PRODUCTION OF METEORITIC-LIKE MOLECU- LES IN SIMULATED INTERSTELLAR ICES Jason P. Dworkin1, Max P. Bernstein1, Samantha F. M. Ashbourn2, Scott A. Sand- ford, Laura T. Iraci and Louis J. Allamandola NASA-Ames Research Center, MS 245-6, Moffett Field, CA 94035 USA; 1 Also of the SETI Institute, 2035 Landings Drive, Mountain View, CA 94043 USA; 2 Also of SRI International 333 Ravenswood Avenue, Menlo Park, CA 94025 USA

Many of the volatiles in interstellar dense clouds exist in ices surrounding dust grains. The low temperatures of these ices (T < 50 K) preclude most chemical reactions, but ionizing radiation can drive reactions that produce a suite of new species, many of which are complex organics. The Astrochemistry Laboratory at NASA-Ames Research Center studies the UV radiation processing of interstellar ice analogs to explore links between interstellar chemistry, the organics in meteorites, and the origin of life on Earth. The high D/H ratios in some interstellar species, and the knowledge that many of the organics in primitive meteorites are D-enriched, suggest that such links are plausible (cf. Sandford et al., 2001). Once identified, the spectral properties of the products can be quantified to assist with the telescopic search for these species in space. Of particular interest are our findings that UV photolysis of interstellar ice analogs produce molecules of importance in current living organisms, including quinones, amphiphiles, and amino acids. Quinones are essential in vital metabolic roles such as electron transport. Studies show that quinones should be made wherever polycyclic aromatic hydrocarbons are irradiated in interstellar ices (Bern- stein et al., 2001). In the case of anthracene-containing ices, we have observed the production of 9-anthrone and 9,10 anthraquinone, both of which have been observed in the Murchison meteorite (Krishnamurthy et al., 1992). Amphiphiles are also made when mixed molecular ices are irradiated. These amphiphiles self- assemble into auto-fluorescent vesicles when placed in liquid water, as do Murch- ison extracts (Dworkin et al., 2001). Irradiation of plausible ices can also produce alanine, serine, and the glycerol-glyceric acid-glycine series (Bernstein et al., 2002). This suggests that some of the oxidized aromatics, amphiphiles, amino 528 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 acids, hydroxy acids, and other compounds found in meteorites may have preceded parent body aqueous alteration.

References

Bernstein, M., Dworkin, J., Sandford, S. and Allamandola, L.: 2001, Ultraviolet Irradiation of Naphthalene in H2O Ice: Implications for Meteorites and Biogenesis, Meteoritics and Planetary Science 36, 351–358. Bernstein, M., Dworkin, J., Sandford, S., Cooper, G. and Allamandola, L.: 2002, The Formation of Racemic Amino Acids by Ultraviolet Photolysis of Interstellar Ice Analogs, Nature 416, 401– 403. Dworkin, J., Deamer, D., Sandford, S. and Allamandola, L.: 2001, Self-Assembling Amphiphilic Molecules: Synthesis in Simulated Interstellar/Precometary Ices, Proc. Nat. Acad. Sci. USA 98, 815–819. Krishnamurthy, R., Epstein, S., Cronin, J., Pizzarello, S. and Yuen, G.: 1992, Isotopic and molecular analyses of hydrocarbons and monocarboxylic acids of the Murchison meteorite, Geochim. Cosmochim. Acta 56, 4045–4058. Sandford, S. A., Bernstein, M. P., and Dworkin, J. P.: 2001, Assessment of the interstellar processes leading to deuterium enrichment in meteoritic organics, Meteoritics and Planetary Science 36, 1117–1133.

HETEROGENEOUS PHOTOCATALYSIS IN NATURE: THE PRE-BIOLO- GICAL CHEMICAL EVOLUTION OF PRIMITIVE EARTH AND SYN- THESIS OF COMPLEX ORGANIC COMPAUNDS IN INTERSTELLAR MEDIA A. V. Emeline1, V. A. Otroshchenko2 , V. K. Ryabchuk3 and N. Serpone1 1 Department of Chemistry & Biochemistry, Concordia University, Montreal (QC), Canada H3G 1M8, e-mail: [email protected]; fax: (+1) 514-848-2868; 2 Bakh Institute of Biochem- istry, Russian Academy of Science, Moscow, Russia, fax: (095) 954-27-32, e-mail: [email protected]; 3 Department of Photonics, Institute of Physics, St-Petersburg State University, Saint-Petersburg, Russia

The potential role of heterogeneous photochemical reactions, in particular heterogeneous photo-catalysis in gas/solid systems in the abiogenesis of Primitive Earth and in Interstellar Medium [1,2, 3] is discussed in light of novel data obtained during the last decade. Brieﬂy, heterogeneous photocatalysis (HPC) can be deﬁned simply as:

A + Cat + light → B+Cat(1) (1) where A and B are chemical reagents and products, respectively, in the gaseous or liquid phase, and Cat denotes the solid photocatalyst. Thus HPC is the gener- alization of thermal heterogeneous catalysis (acceleration of the reaction rate with conservation of the catalyst Cat) and photochemistry (involve-ment of free energy ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 529 in the process). HPC can also be treated as a special case of biological photosynthesis. The latter includes the self-reproduction of the photosynthetic system, Cat, whereas in photocatalysis it is the reactivation of Cat during a sufficiently high number of catalytic cycles. When the catalytic cycle in (1) is not complete (i.e. Cat is not restored), the process is best described as a heterogeneous photochemical stoichiometric (HPS) reaction. Heterogeneous photocatalysis has been established as a common and widespread phenomenon. In the past, the possible role of HPC (and HPS) reactions in natural processes occurring on Earth and in Interstellar Medium in past and present time may be considerable owing to following considerations: 1. Any component (neutral, basic, acidic) of the Primitive Atmosphere can be involved in gas/solid HPC (or HPSR) reactions that yield pre-biological organic compounds. 2. Metal oxides and salts may have been involved in any of the stages in the formation of the primitive and modern Lithosphere. These oxides and salts can act as active solid photocatalysts on Earth. The solid stardust particles are also could serve as photocatalysts, especially, silicate dust particles. 3. Reactions of different kinds, which include radical reactions that lead to formation of multi-carbon compounds – in particular to formation of ethane, propane and ethylene from methane – take place at the surface of solid photocatalyst particles under illumination in a wide range of temperatures (∼ 77 K to ca. 500 K) and in wide range of gas pressures including the zero pressure limit. In the latter case, reactions can occur between pre-adsorbed reagents at solid surfaces. Accordingly, it is possible to infer that proper conditions exist for the synthesis of organics in Interstellar Space on the surface of dust particles. 4. The considerable red spectral shifts of the HPC reaction limits (up to 5 eV) and sufficiently high quantum yields (∼ 0.01 – 0.1) of HPC on the solid photo-catalyst can increase the efficiency of solar power utilization by several orders of magnitude compared to the efficiency of the corresponding gaseous photochemical reactions of free water vapor, carbon dioxide, methane, ammonia and other molecules. A tentative estimate of the efficiencies of HPC reactions based on laboratory results extrapolated to a hypothetical ‘natural catalyst of moderate activity’ shows that HPC (or HPSR) could play a significant role in abiogenesis. Added support for this hypothesis is the considerable efficiency of natural HPC reactions in the present Atmosphere [4]. 5. Complex organic molecules can be formed from monomers via HPC (or HPS) reactions on the surface of natural minerals [5]. Thus, HPC reactions could be involved in natural abiogenesis starting from synthesis of small molecules up to polymers. 6. Some special topics of HPC and HPS occurring in gas/dust clouds treated as a systems (both in planet atmospheres and in Interstellar Medium) favor to abiogenic synthesis. The dust particles: i) can be the collectors of molecules (reagents) due to pre-adsorption; ii) during UV excitation, the solid (photo)catalysts store 530 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 energy as a result of the formation of so-called color centers or space-separated trapped charge carries, i.e. photoelectrons and photoholes. The stored energy can be released in chemical pathways as post-irradiation surface reactions occurring in the dark (“memory effect” or post-sorption) or during additional long wavelength photostimulation or thermal stimulation of photocatalysts in the dark [6]. Thus, the overall heterogeneous processes could involve stages of irradiation of solid photocatalysts and surface chemical reactions separated in space and time through the stage of particle transport from the zone of primary irradiation to the zone of reaction in gas/solid dust cloud. In addition, the spectral selectivity of photocatalysts [7], are similar to the general features found in the photochemistry and photobiology on modern Earth favorable to Life. In particular, the spectral selectivity of many metal-oxide photocatalysts in relation to the complete oxidation of methane or conversion of methane to ethane, ethylene and other hydrocarbons, manifests itself as dominating the chemical yields of the conversion products under the action of “red light” (extrinsic absorption bands of solid photocatalysts) as compared with the selectivity of products from complete oxidation. The inverse situation takes place under “blue light” (the fundamental absorption bands of catalysts). Thus, the heterogeneous system involving photocatalyst particles in gas/solid dust clouds could serve as a “self-protecting” system in relation to the synthesis of organics similar to what occurs in the modern Atmosphere which contains a “life-protecting” ozone layer.

References

Terenin, A. N.: 1959, in A. I. Oparin (ed.), The Origin of Life at the Earth (in Russian), Academy of Sciences, USSR, Moscow, pp. 144–146. Ehrenfreund, P. and Charnley, S. B.: 2000, Organic Molecules in the Interstellar Medium, Comets, and Meteorites: A Voyage from Dark Clouds to the Early Earth, Ann. Rev. Astron. Astrophys. 38, 1–51. Otroshchenko, V.A., Kritsky, M. S., Vasilyeva, N. V., Alekseev, V. A., Ryabchuk, V. K. and Bagautdinov, R. R.: 2002, in: J. and K. Tran Thanh Van et al. (eds.), Formation of organic substances in interstellar medium: approaches to physicochemical modeling, XIIemes Rencontres de Blois, Frontiers of Life, (in press). Parmon, V. N. and Zakharenko, V. S.: 2001, Photocatalysis and photosorption in the Earth atmosphere, Cattech. The magazine of Catalysis 5, 96–115. Strigunkova, T. Ph., Lavrentjev, G. A. and Otroshchenko, V. A.: 1986, Abiogenic Synthesis of Oligonucleotides on Kaolinite under the Action of Ultraviolet Radiation, J. Molec. Evol 23, 290–293. Emeline, A. V., Kataeva, V. A., Ryabchuk, V. K. and Serpone, N.: 1999, Photostimulated generation of defects and surface reactions on a series of wide band-gap oxides, J. Phys. Chem. B. 103, 9190–9199. Emeline, A., Salinaro, A. and Serpone, N.: 2000, Spectral dependencies and wavelength selectivity in heterogeneous photocatalysis, J. Phys. Chem. B 104, 11202–11210. ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 531

HYDROCARBON PRODUCTION UNDER HYDROTHERMAL EUROPAN CONDITIONS AND ITS IMPLICATIONS TO THE MAINTAINANCE OF LIFE Lilia Montoya-Lorenzana1 , Rafael Navarro-González1 , Wanda Davis2 and Chris- topher McKay3 1 Laboratorio de Química de Plasmas y Estudios Planetarios, Instituto de Ciencias Nucleares, Uni- versidad Nacional Autónoma de México, Circuito Exterior, C.U., Apartado Postal 70-543, México D.F. 045100, México, e-mail: [email protected]; 2 SETI Institute and Space División, NASA-Ames Research Center, Moffet Field, CA 94035, USA; 3 Space Science Division, NASA-Ames Research Center, Moffet Field, CA 94035, USA

Many different lines of geological and geophysical evidences point to the possibility of a liquid subsurface ocean on Jupiter’s moon, Europa. Europa has an icy core enough thick to prohibit solar radiation to penetrate into the ocean hence photosynthesis is ruled out. It has been proposed that hydrothermal systems could potentially harbor isolated microbial communities that obtain their energy chemoautotrophic- ally. Hypothetical hydrothermal conditions on Europa (temperature, pressure, gas phase composition(s) and mineral composition) were reproduced in laboratory inside a high temperature and pressure reactor. Gas mixture samples were analized using GS-MS techniques. We provide evidence that in the presence of pyrite methane is oxidized to carbon dioxide. Other hydrocarbons were produced, isomers from C2 to C7. Other families synthetized were alcohols, ketones, aldehydes, thiols, ethers and aromatics. This result might have also interesting consequences on the sustainability of life on Europa by two kinds of methanogenesis driven by cleavage of hydrocarbons and by reduction of CO2 to CH4 using H2. This idea is supported by theoretical models of hypothetical geochemical conditions on hydrothermal systems on Europa which predict the oxidation of methane and also by recent discoveries of anaerobic hydrocarbon degraders bacteria on extreme terrestrial environment.

THE GAS- AND CONDENSED-PHASE PRODUCTS OF CORONA DIS- CHARGES ON TITAN Sandra I. Ramírez1,2 and Rafael Navarro-González1 1 Laboratorio de Química de Plasmas y Estudios Planetarios, ICN, UNAM, Mexico; 2 Centro de Investigaciones Químicas, UAEM, Mexico, e-mail: [email protected]

A comprehensive study of the gas- and condensed-phase products originated by corona discharges in a Titan’s simulated atmosphere has been developed. Mixtures of methane in nitrogen have been subjected to irradiation periods of 30 minute with positive and negative coronas originated from a DC regulated power source. Dif- ferent experimental parameters like the current intensity, the initial pressure, and the methane mol fraction, have been varied in order to determine their effect in the energy yield of the identiﬁed gas-phase products. The products were separated and 532 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 identiﬁed by the coupled GC-MS techniques. The calculation of the energy yields of each of the 26 products was done using calibration curves and measurements of electrical dissipated power. A canonical mixture of 10% methane in nitrogen has also been irradiated up to 200 hours with a Tesla coil to produce Titan’s aerosol analogues. A suite of spectrometric and separation techniques have been utilized to get information that helps to determine the chemical characterization of these aerosol analogues. The IR spectra show the presence of important chemical fragments like -C≡N; -N- H; -C=C; together with chains of hydrocarbons. 1HNMR spectra evidence the existence of nitrogen-based rings and heteroaromatic compounds. The gathered information in the two types of experiments can help to understand in more detail the role of the proposed methane clouds in Titan’s lower atmosphere, the existence of electrical discharges as the energy dissipating mechanism, and the chemical nature of the tholins or suspended aerosols that exist in the upper atmospheric layers. These implications will be presented and discussed with more detail. The potential use of this information in the interpretation of the data collected by the Cassini-Huygens mission on the year 2004 will be also discussed.

METHANE AND HYDROCARBON PRODUCTION BY VOLCANIC ERUP- TIONS ON EARLY MARS Antigona Segura and Rafael Navarro-González Laboratorio de Química de Plasmas y Estudios Planetarios, Instituo de Cienicas Nucleares, Uni- versidad Nacional Autónoma de México. Circuito Exterior, Ciudad Universitaria, Apartado Postal 70-543. México D.F. 04510, México

Geologic evidence and numerical simulations indicate that explosive volcanism was widely distributed through out Mars. Explosive volcanism is characterized by the formation of ﬂoating plumes composed of ashes and volcanic gases that ac- quire electric charge during their ejection into the atmosphere producing lightning discharges. This geologic setting was simulated to study the chemical effects of lightning in early Mars. Simulated martian magmatic gases contained CH4,H2, H2OandN2, according to the model of Kuramoto (1) and the nitrogen content measured in Chassigny and the nakhlites (2). Lightning was simulated by focusing a high energy infrared laser beam inside of a Pyrex reactor that contained the volcanic gas mixture. The analysis of products was performed using a gas chro- matograph coupled to an infrared detector and a quadrupole mass spectrometer. Eleven hydrocarbons were identiﬁed among the products, being acetylene (C2H2) the most abundant. A termochemical model was used to predict which compounds were directly formed by volcanic heat. In this case, acetylene and ethylene are formed at 1500 K. Methane and another larger hydrocarbons have been proposed as a possible greenhouse gases on early Mars. In this work we present the amount that may be injected by volcanic plumes according to the thermochemical model and experimental simulations. ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 533

References

Kuramoto, K.: 1997, Phys. Earth Planet. Int. 100,3. Wright,I.P.et al.: 1992, Geochem. Cosmochem. Acta 56, 817.

SPECTROSCOPIC CHARACTERIZATION OF THE SIMULATED TITAN HAZE FORMED IN A PHOTOCHEMICAL FLOW REACTOR Buu N. Tran1, James P. Ferris1, Peter D. Persans2 and John J. Chera3 1 Rensselaer Polytechnic Institute, Department of Chemistry, Troy, New York 12180; 2 Rensselaer Polytechnic Institute, Department of Physics, Troy, New York 12180; 3 General Electric Corporate Research and Development Center, Schenectady, New York 12301

The formation of Titan haze is simulated by UV photolysis of a mixture of gases, with mixing ratios that approximate those on Titan, in a ﬂow system (Clarke et al., 2000). A detailed investigation of the real (n) and imaginary (k) parts of the complex refractive index of the polymers formed in the 0.2 < wavelength < 2.5 microns region using an UV-VIS near IR spectroscopy is reported for comparison with laboratory data (Khare et al. 1984) and observations from the Voyager space- craft. The molecular structure of generated polymers has been also investigated by a combination of microscopic Fourier Transform Infrared (FTIR) and X-ray Photoelectron Spectroscopy (XPS). UV spectral measurements suggest the presence of conjugated units of double bonds, some of which may be conjugated with other functional groups. n has a value of 1.5 to 1.6 throughout the 0.2–2.5 microns region. The value of k increases from 0.02 to 0.2 in the 0.2–0.8 micron region and has values consistent with Titan haze measurement (McKay et al. 1989). FTIR established the presence of CH3,CH2, C=C, C=C-C≡N and possibly N-H functional groups in the polymer. The C:N ratio in the polymer was determined to be 17.6:1 by XPS analysis. These laboratory ﬁndings will be valuable in understanding the data returned from the Huygens probe as it passes through Titan’s atmosphere in 2005.

References

D. W. Clarke, J. C. Joseph and J. P. Ferris: 2000, Icarus 147, 282–291. B. H. Khare, C. Sagan, E. T. Arakawa, F. Suits, T. A. Callcott and M. W. Williams: 1984, Icarus 60, 127–137. McKay, C. P., Pollack, J. B. and Courtin, E.: 1989, Icarus 80, 23–53 (1989). 534 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

PRODUCTION OF HYDROCARBONS AND NITRILES BY LIGHTNING IN A MODEL OF TITAN’S ATMOSPHERE.EFFECT ON METHANE MIX- ING RATIO José G. de la Rosa and R. Navarro-González Laboratorio de Química de Plasmas y Estudios Planetarios, Instituto de Ciencias Nucleares, Uni- versidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, Apartado Postal 70-543, México D.F. 04510, Mexico

Although lightning has not been observed in Titan’s atmosphere, the presence of methane rain in the troposphere suggests the possibility of electrical activity in the form of lightning discharges. Here we examine the chemical effects of these electrical processes on a Titan simulated atmosphere composed of CH4 in N2 at various mixing ratios. Lightning discharges were simulated by a hot and dense plasma generated by a Nd-YAG laser and the ﬁnal products were separated and detected by GC-FTIR-MS. The main products were unsaturated hydrocarbons and nitriles. ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 535

ASTROBIOLOGY/ EXOBIOLOGY 536 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

ECOSPHERE OF MAIN SEQUENCE STARS Y. Peña-Cabrera and H. J. Durand-Manterola Departmento de Física Espacial, Instituto de Geofísica. UNAM, C.P. 04510, Mexico D.F., Mexico, e-mail: [email protected]

Around a star exist a region in which the temperature of a planet is the best for life. This region is the ecosphere. Taking the extreme temperature at which the organisms could live at Earth (Hipertermophyles and psicrophyles organisms) we obtained the ecosphere for the different spectral types of the main sequence stars. We found that at high stellar temperature the ecosphere is wider and then the probability of found a planet with life grows with the luminosity of the star. But on the other hand if the luminosity grows the time life of the stars are shorter and the possibility that the life arise in the planets surrounding that stars diminishes. Then we conclude that the maximum probability of found planets with life is around stars type F, G, or K.

PREBIOTIC POCESSES IN PRESENCE OF EXTRATERRESTRIAL MIN- ERALS ON BOARD OF “MIR” SPACE STATION -APPROXIMATE MODEL OF COSMIC BODIES SURFACE N. B. Gontareva and E. A. Kuzicheva Institute of Cytology, Laboratory of Exobiology, Tikhoretsky pr. 4, 194064, StPetersburg, Russia, e-mail: [email protected]

Life, defined as a chemical system capable of transferring its molecular information and also capable of evolving, might have originated at the early Earth or elsewhere in the Universe. Modern scientific data witness, that cosmic bodies such as comets and meteorites served as an important deposit of organics delivered to the primitive Earth at the initial stages of chemical evolution. According to the calculation, made by Anders et al., the contribution of meteorites was about 30 tons per day (1000 times more than nowadays). Carbonaceous chondrites could carry up to 1020 tons of carbon within the period of 300 million years. The study of meteorites, particularly the carbonaceous chondrites, has allowed close examination of extraterrestrial organic material. It is quite possible that some space-made organic molecules could be safely transported to Earth vicinity being associated with mineral grains. It is important to test whether such important substances as nucleotides synthesized in Earth orbit could be protected by Lunar soil, which is, in fact, the mixture of meteorite powder and cosmic dust, accumulated within billions of years at the Moon’s surface. Besides, the Earth orbit provides unique opportunity to expand the exposure period due to the fact the amount of solar radiation at the orbit during two-weeks flight is equal to the interstellar one within the period of 2*106 years. The conditions of lengthly space flight were performed during the experiment in terms ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 537 of joined French-German-Russian experiment “Perseus” on board of Mir space station. The duration of the experiment was as long as 3 months. The phosphorylation of adenosine, uridine and thymidine has been studied in this context. After retrieval, HPLC and mass spectrometry analysis were used to identify all the mononucleotides of certain nucleosides. 5’monophosphates pre- vailed in every experimental setup. It has been shown, that exposure of the investigated nucleosides as dry films in space conditions in the presence of lunar soil increases the yield of synthesized nucleotides in 1.1 – 3.0 times as compared with the exposure of the same samples in absence of lunar soil. Decrease of initial products was less pronounced as well in the presence of mineral bed. To identify and evaluate the principal source of energy in open space responsible for nucleotide synthesis reaction laboratory experiments were performed. It has been shown, that vacuum ultraviolet (145 nm) and ultraviolet (254 nm) radiation promotes nucleotide synthesis while the presence of Lunar soil increases reaction yield in 1.5 – 2.0 times. Formation of 5’-mononucleotides seemed to be the most effective reaction both in flight and in laboratory experiments.

PRELIMINARY PROGRAM FOR ANALYSIS OF MARS SAMPLES Maurel, M-C 1 and Counil J-L2 1Institut Jacques Monod, Tour 43, 2 Place Jussieu, F-75251 Paris Cedex, France; 2 CNES Centre de Toulouse, 18 av. Edouard Belin, 31401 Toulouse Cedex4 and the French C.S.E.E.M.

A multi-disciplinary committee of scientists emerged in France since 1999, whose work is devoted to Mars sample return. Basing on the assumption that key ingredi- ents for life, liquid water and a source of energy were present on ancient Mars, groups are currently developing strategies to detect potential extinct and/or extant life. To confirm the potential controversial of discovering life, the most sensible idea before the return of samples, is to perform high sensitive in situ analyzes exploring well-defined sites from the surface and subsurface. For this purpose, a large community from geology, astrophysic, chemical and biological sciences works to build an interdisciplinary frame, defining sites of interest, physical and chemical conditions for remote sensing and in situ approaches, devising fast, highly resolvent, and non-destructive methods. The first step of our program is to draw up a general protocol (including recom- mendation according to planetary protection), then to optimize methodologies and to produce experiments under conditions mimicking those that are characteristic of the planet mars (irradiation, temperature, pressure, hydrous potential, salts etc.) 538 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

EFFECT OF HIGH SALT CONDITIONS ON STABILIZATION OF RNA STRUCTURE AND FUNCTION AT HIGH TEMPERATURE Vergne Jacques1, Blanc-Valleron Marie-Madeleine2 , Cornée Annie2, Rouchy Jean- Marie2 and Maurel Marie Christine1 1 Biochimie de l’Evolution et Adaptabilité Moléculaire, Institut Jacques Monod, Tour 43, 2 place Jussieu, 75251 Paris cedex 5, France; 2 CNRS- Muséum national Histoire Naturelle, Laboratoire de Géologie, 43, rue Buffon, F-75005 Paris, France

The fragility of RNA structure and function is the subject of controversy and requires direct experimental characterisation. We have already shown the structural integrity of tRNA at high temperature –82◦C for 30h – in high salt concentrations (Tehei et al., 2002). Stability were also performed by measuring the residual speciﬁc tRNA charge capacity after heat treatment for 30 h at 82 ◦C. We are now involved in selection of RNA molecules at high temperature in presence of an ancient halite (NaCl) sample (reference: EZ08-K6-C9). This sample, collected in a borehole at 720.15 m depth, belongs to the Rupelian Upper Salt Formation of the Bresse salt basin (France). Its age is estimated to about 31±3 millions years. These studies provide support for the importance of salt to protect macromolecules against thermal degradation allowing activity to be recovered. These could be useful for searching traces of life in ancient sediments and in planetary exploration.

References

Tehei Moeva, Franzetti Bruno, Maurel Marie-Christine, Vergne Jacques, Hountondji Codjo and Zaccai Giuseppe: 2002, Extremophiles, in press.

(INTERMITTENT) WATER ON MARS: CHEMICAL EVOLUTION & THE AIR-WATER INTERFACE Louis Lerman Department of Chemistry, Philipps University, Marburg, Germany, email: [email protected]

The author’s accompanying paper outlines, with regard to planetary prebiotic chemical evolution, consequences of the chemical physics of the air-water interface at the microscale (i.e. the bubble-aerosol cycle). Applying this to Mars mission planning: The ﬁnding of bubble-aerosol-generated objects (“nanobacteria”- like) of Mar- tian origin in Martian meteorites or on Mars itself is prima facie evidence for the existence of a complex Martian hydrology cycle capable of gathering, concentrating, and transporting organics. ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 539

The presence of such bubble-aerosol objects in (or from) an extraterrestrial loc- ation would demonstrate that substantial environmental opportunities have existed for the support of prebiotic chemical evolution. Speciﬁcally, on the tectonically simple early Mars (one having liquid water intermittently on its surface), such a complex hydrology cycle was likely to be the only initiator and supporter of the rapid cycles of concentration, hydration, and dehydration necessary for organic polymerization in ‘bulk’ quantities. Thus, if chemical self-organization occurred on Mars it was likely to be a consequence of a bubble-aerosol cycle analogous to the terrestrial. Therefore any life-searching Mars missions (or interpretations of Martian objects having made their way to Earth) must discriminate between the fossils of living systems at the nanobacterial scale and potential artifacts of the bubble- aerosol cycle necessarily found on any planet, planetoid, or satellite having both liquid water and amphiphiles. Additionally, IF bacteria (with surface active membrane elements) have existed on Mars, then these same bubble-aerosol processes could have been a prime mode of concentration and aerial transport. In analogy to terrestrial processes the larger of these bubble-aerosol generated objects (in their hydrated state) could easily have transported such bacteria across a mostly arid planetary surface. This would have been useful for ‘colonization’, and could also explain the deposition and subsequent fossilization of ‘micro-clumps’ of such bacteria in environments much removed from their origin.

FROM ORIGINS AND EXTREMOPHILES LIVING ON THE EDGE TO POSSIBILITIES OF EXTRATERRESTRIAL LIFE Joseph Sechbach P. O. Box 1132, Efrat 90435 Israel

The origin of Life is still mysterious and speculative. It is assumed that the primordial environments on Earth were more extreme than those existing today in most habitats. On the other hand, there are some places on our globe whose environments resemble those which supposedly existed on young Earth. Still active in those extreme places is microbial life that may represent the initial biota evolved on young Earth. Microorganisms living in hyperthermophilic conditions have been observed in hydrothermo vents in the depths of the ocean and in hot springs. Drilling to the subsurface depth also reveals living microbial species functioning at extreme high temperature levels. Microbial life occurs in deep frozen areas, such as permafrost or under the glaciers in Siberia, Arctic zones, and Antarctica. Drilling to the depth of a few thousand meters at Vostok Station (Antarctica) revealed microbial traces beneath the surface ice sheets. Furthermore, there is strong evidence that at the depth of 540 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

4 km under the ice layers, there is a large liquid water lake that might harbor living microorganisms. Microbial representatives (Prokaryotes and Eukaryotes) have been found in hypersaline bodies (such as in the Dead Sea [Israel] and in the Great Salt Lakes [Utah, USA]). Likewise, there are organisms that thrive in the extreme ranges of acidic (acidophiles) or alkaline (alkaliphiles) environments, others under heavy pressures occurring in the bottom of the oceans and in subsurface environments. Several organisms are able to thrive under atmospheres of various gases (ammonia, CO2,H2) or in niches lacking oxygen. We will propose that those extremophiles may well represent models of micro- candidates for extraterrestrial life as might exist on celestial worlds such as Mars or in the Jovian satellite Europa.

PICO DE ORIZABA: A TROPICAL ALPINE ENVIRONMENT AS A MAR- TIAN ANALOG Itzel Pérez Chávez1, Rafael Navarro González1, Christopher P. McKay2 and Luis Cruz Kuri3 1 Laboratorio de Química de Plasmas y Estudios Planetarios, Instituto de Ciencias Nucleares, UNAM; 2 Space Science Division, NASA Ames Research Center; 3 Instituto de Ciencias Básicas, Universidad Veracruzana

Ecological succession in mountain environments have been compared to ecological succession during the greening of the Red Planet. And, within the alpine environments, tropical ones have an advantage: If life is going to be introduced to Mars, the ﬁrst place where temperature will reach clement levels for different forms of life will be on Martian tropics, where seasonality is low. Here, we propose the environment at Pico de Orizaba, a dormant volcano more than 5,610 meters high and Mexico’s highest peak located at 19◦01N and 97◦16W, as an analog for the Martian terraforming process. One of the most conspicuous vegetation boundaries is treeline, which in the terraforming analogy will mark the time when the conditions are favorable for tree introduction. Hence, since 1999 we are studying the environmental conditions (air temperature and humidity, soil temperature and organic matter content) at the highest alpine treeline on Earth located at Pico de Orizaba in order to determine the environment where this boundary occurs.

ORGANIC CONTENT OF ATACAMA DESERT SOILS ALONG THE NORTH TO SOUTH GRADIENT Rafael Navarro-González1 , Christopher P. McKay2 and Paola Molina1 1 Laboratorio de Química de Plasmas y Estudios Planetarios, Instituto de Ciencias Nucleares, Uni- versidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, México D.f. 04510 Mexico; 2 Space Science Division, NASA-Ames Research Center, Moffett Field, CA 94035-1000, USA ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 541

The Atacama desert is one of the driest and oldest deserts of the world that extends across 1,000 km from 30 ◦Sto20◦S along the Pacific coast of South America. Geological and soil mineralogical evidence suggest that extreme arid conditions have persisted in this desert for about 10–15 Myrs. We have collected surface soil samples (first 5 cm layer) from the driest parts of the Atacama desert (24 ◦S) to the less arid zones (28 ◦S) along a transect at about 70 ◦W. The samples were freeze-dried and then subjected to flash pyrolysis at 750 ◦C for 1 min in a helium atmosphere. The resultant gas fragments were separated by gas chromatography and identified by mass spectrometry. The samples from the most arid zones are basically free of organic matter. No organics are detected using scan mode (10– 100 m/e) mass spectrometry. Benzene and toluene are just barely detectable using selective-ion-monitoring mass spectrometry.

STATISTICAL ASPECTS RELATED TO THE DETECTION OF SPATIAL AND TEMPORARY PATTERNS OF SOME CLIMATE PARAMETERS AROUND THE TIMBERLINE OF PICO DE ORIZABA Luis Cruz-Kuri1, Nahum Castillo-González1 , José Mora-Domínguez1, Christopher P. McKay 2, and Rafael Navarro-González3 1 Insituto de Ciencias Básicas. Universidad Veracruzana; 2 NASA-Ames Research Center; 3 Instituto de Ciencias Nucleares, UNAM

Pico de Orizaba (19 ◦N) has the highest treeline in the world (4,200 m) and is the subject of an ongoing study by us supported jointly by the National Aeronautics and Space Administration (NASA), the National Autonomous University of Mex- ico (UNAM), and the University of Veracruz (UV). This ongoing work is related to the survival of ecosystems in extreme environments with applications to life on Mars. Related to this, we address the question why life is constrained at high altitudes in our planet, we particularly focus to the search of those factors that determine timberline. The treeline in temperate zones appears to be determined by summer temperatures- trees grow when the warmest summer month has an average temperature of 10 ◦C or above. We hypothesize that tropical treelines, in contrast, are more sensitive to annual average temperature. In addition our current work indicates that the treeline on Pico de Orizaba reﬂects the temperature dependence of the nitrogen cycle. Since March 1999 we started to monitor the environmental conditions of the mountain. A detailed database is needed to quantitatively understand the current position and elevation of treeline. The present report addresses some statistical aspects pertaining to the above undertaking, mainly form the perspective of soil temperature as well as external temperature at various locations of the mountain. 542 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

PROTECTION OF BACTERIAL SPORES IN SPACE, A CONTRIBUTION TO THE DISCUSSION ON PANSPERMIA Gerda Horneck, Petra Rettberg, Günther Reitz, Corinna Panitz, and Elke Rabbow German Aerospace Center DLR, Institute of Aerospace Medicine, D 51170 Koeln, Germany, e-mail: [email protected]

Meteorites may be natural vehicles for transporting resistant life forms, such as bacterial spores, through space. To tackle the question whether and to what extent soil or rock material may protect bacterial spores against the harsh environment of space, especially solar UV radiation, we have exposed spores of Bacillus subtilis to space (i) unprotected, (ii) under a thin filter of clay, and (iii) mixed with different soil, rock or meteorite powders. Exposure was done in the BIOPAN facility of the European Space Agency onboard of the Russian Earth-orbiting Foton satellite. After about 2 weeks in space, the survival was tested from the number of colony formers. Unprotected spores in layers open to space or behind a quartz window, even behind a thin layer of clay, survived barely, if at all, the space trip. Mixing the spores with powder of clay, rock or meteorites increased the survival rate by 5 orders of magnitude. Up to 100 % survival was reached in 1 cm cubes of soil mixtures containing spores in concentrations comparable to that in natural soil. These data confirm the deleterious effects of extraterrestrial solar UV radiation. However, they suggest that in a scenario of interplanetary transfer of life, small rock ejecta of a few cm in diameter could be sufficiently large to protect bacterial spores against the intense insolation.

References

Horneck et al.: 2001, OLEB 31, 527–547.

UV RADIATION AND HABITABLE ZONES Buccino, A.1, Lemarchand, G.2,3 and Mauas, P.1 1 Instituto de Astronomía y Física del Espacio, CONICET, Argentina; 2 Centro de Estudios Avanza- dos, UBA, Argentina; 3 Instituto Argentino de Radioastronomía, CONICET, Argentina

We have studied the UV radiation emitted by a several nearby stars, in the range 1800 to 3300 A, in order to determine the constrains on the habitable zone posed by the radiation levels. The observations were taken from the International Ultraviolet Explorer and the Hubble Space Telescope satellites database. The stellar sample was chosen to cover the range of what are usually called solar-type stars, from late F to K stars. In addition, we included all stars with exo-planets for which observations are available. ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 543

SURVIVABILITY OF PHOSPHORYLATEDNUCLEOSIDES DURING THE ATMOSPHERIC PASSAGE IN SOLAR OR EXTRASOLAR HABITABLE BODIES Campins, J.1, Marcano, V.1, Matheus, P.1, Cedeño, C.2, Benitez, P.1, Falcón, N.3 and Palacios-Prü, E.1 1 Laboratory of Evolutionary Biology and Chemistry, Electron Microscopy Center, University of the Andes, P. O. Box 163, Mérida, Venezuela, e-mail: [email protected]; 2 Crystalography Laboratory, Faculty of Sciences, ULA, Mérida, Venezuela; 3 Departamento de Física, Facultad de Ciencia y Tecnología, UC, Valencia, Venezuela

There are evidences that space energy sources such as electric discharges, UV- photons, solar wind, solar flare ions, and cosmic rays could give place to the appearance of phosphorylated and non-phosphorylated nucleosides (Cronin & Chang, 1993; Cooper et al., 2001; Simakov & Kuzicheva, 2001). These compounds may have been delivered mainly by IDPs to the planetary surfaces, and thereby consti- tuting a starting material for early biological activity. These compounds could be also transfered from one planet to another by ejecting from the planet by an impact scenario, facing the hostile environment of space and the atmospheric entering process. For IDPs having 10−6–10−5 m, atmospheric deceleration can produce moderate (< 500 ◦C) full depth heating according to several evidences. In this report, we communicate the results of simulated pyrolitic studies for survivability of AMP, ADP and adenosine at temperatures < 500 ◦C and at various time inter- vals. The main objectives of this study were: 1, to know the survivability of AMP, ADP, and adenosine during its entry to the atmosphere of Earth-like planets, and 2, to determine the protective effects of a meteoritic and organic matrix on these biomolecules during its entry to the atmosphere. Meteoritic powder was obtained from the Vigirima mesosiderite, which was analyzed by X-ray powder diffraction. Experiments were carried out in a sublimator- reactor, model CME-RQE-2, characterized by an infrared-generator coil placed around a stainless steel cell containing a quartz-microcapillar. Samples were de- posited into this microcapillar and thereby the steel cell was hermetically sealed and evacuated. When heated, the content of the microcapillar reached 100% of its final temperature within ∼ 30 seconds. This was measured by a thermocouple gauge inserted into the microcapillar. A fast cooling of the samples was obtained by dispersing CO2 gas on the steel cell. Heavy mineral oil was used as a model of primordial hydrocarbons > n-C18. All the raw products were extracted and separated from the mineral oil and the meteoritic matter. The solutions were analyzed on HPTLC Merck 60 F254 plates. Quantification of the products was made by running large samples as bands that were detected with the help of an UV-254-lamp, eluted with water, and analyzed by spectrophotometry at 260 nm against blanks. Results revealed that nucleotides and nucleosides transported by IDPs could be delivered to habitable planets or bodies and thereby surviving temperatures up to 500 ◦C as the ones generated during atmospheric entering process. However, atmospheric passage should not exceed a time > 150 seconds due to the thermal lability 544 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 of these molecules. Because of the high half-life showed by them in presence of meteoritic powder, it is though that extraterrestrial delivery of nucleotides is more suitable under protected conditions. These data indicate that the formation of a Fe- complex could be increasing their stability in presence of meteoritic matter. The results obtained in the presence of a matrix composed by meteoritic powder and hydrocarbons revealed the lower half-life, indicating a major pyrolytic effect. Our results suggest also that extraterrestrial spores having free energy carriers based on similar compounds could be transfered by IDPs from one planet to another toler- ating the hostile conditions of the atmospheric passage. Therefore, if the synthesis of nucleotides and oligonucleotides could take place in ice bodies, then delivers as IDPs could be contributing with the arising of biological activity in extrasolar early Earth-like bodies.

References

Cooper, G., Kimmich, N., Belisle, W., Sarinana, J., Brabham, K. and Garrel., L.: 2001, Nature 414, 879–883. Cronin, J. R. and Chang, S.: 1993, in: Greenberg, J. M., Mendoza-Gómez, C. X. and Pirronello, V. ( e ds . ) , The Chemistry of Life’s Origins, Kluwer Academic, Dordrecht, The Netherlands, pp. 209–258. Simakov, M. B. and Kuzicheva, E. A.: 2001, in: J. Chela-Flores, T. Owen and F. Raulin (eds.), First Steps in the Origin of Life in the Universe, Kluwer Academic Publishers, Dordrecht, The Netherlands, pp. 167–170.

CULTURE OF EDIBLE PLANTS UNDER SIMULATED SPACE-BASED CONDITIONS UTILIZING NON-CARBONACEOUS METEORITE NUTRI- ENTS Matheus, P.1, Marcano, V.1, Campins, J.1, Cedeño, C.2, Falcón, N.3 and Palacios- Prü, E.1 1 Laboratory of Evolutionary Biology and Chemistry, Electron Microscopy Center, University of the Andes, P. O. Box 163, Mérida, Venezuela, e-mail: [email protected]; 2 Crystalography Laboratory, Faculty of Sciences, University of the Andes, Mérida, Venezuela; 3 Departamento de Física, Facultad de Ciencia y Tecnología, Universidad de Carabobo, Valencia, Venezuela

Several scenarios have been developed to establish eventually human settlements in space stations or bodies, using indigenous space resources (Hossner & Allen, 1989; Stoker, 1993). The uptake of nutrients for hydroponic plant cultures could be obtained mining asteroids or collecting micrometeorites. Carbonaceous and non- carbonaceous meteorites contain nutrients needed for biological activity. Experi- ments carried out with plant tissue cultures of Asparagus officinalis and Solanum tuberosum revealed some enhanced growth in presence of Murchison C2 carbonaceous meteorite extracts. However, similar experiments utilizing non-carbonaceous material are not known. On the other hand, carbonaceous meteorites can also con- ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02 545 tain toxic polycyclic aromatics and phenols which constitute a problem when extracts are considered as culture medium (Mautner et al., 1997). Utilization of edible plants by human settlements in the space should be related to the effects that the unfiltered solar radiation, galactic radiation and negligible gravity would produce on humans. We focus our investigation on the ability of non-carbonaceous meteoritic resource to serve as nutrient source for edible plants (viz. Zea mays, Lycopersicum esculentum,andDaucus carota) cultured by hydroponic techniques and therefore having importance in the health of space communities. We investigate some physiological responses of these plants (viz. chlorophyll content, phaeo- phytinization index, protein production) to several concentrations of meteoritic extracts. Meteoritic powder was obtained from the Vigirima mesosiderite, which was analyzed by X-ray diffraction. Samples of 188.5 mg meteorite powder were extracted by shaking with 1131 µl deionized H2O for 17 h, and after by extraction at 121 ◦C for 15 minutes, under standard sterilizing conditions. Germination was obtained at 25 ◦C under illumination by cool white fluorescent lights with flux of 80 µEm−2 s−1. The liquid substrate contained 45 µl of Milli-Q water and 45 µl of meteorite extract having several concentrations (viz. 5, 10, 20 and 40%). Growth of the young plants was also obtained under these conditions but using dark-light cycles. For the preparation of optimum blanks, 45 µl of deionized water were mixed with 45 µl of standard nutrient solution (Murashige medium). pH was between 4 and 5. In D. carota, results showed a higher germination rate in 5%, 10% and 20% concentrations than in blanks. Germination of seeds was stimulated by meteoritic extracts showing an earlier response than in pesimum blank. Contents of (a) and (a+b) chlorophyll were higher in 5% and 10% concentrations than in 20% and 40% concentrations suggesting an enzymatic inhibitory effect produced by excess of acidic ions (viz. Fe, Ni, Al). This response was correlated to the biomass and develop of the specimens, and to the degradation of chlorophylls to phaeophytin. Plants grown in extracts having 5% concentration exhibited higher values of protein production whereas in pesimum blank and 10%, 20% and 40% concentrations protein production was lower. Similar physiological responses were seen in Zea mays. Our results suggest the usefulness of the non-carbonaceous meteoritic resource as nutrient sources for culture of edible plants in space human settlements conceived as open regenerative systems. These results suggest also the biological potential of the non-carbonaceous matter for the growth of organisms in the early Earth, Mars, and in other planetary bodies beyond our Solar system.

References

Hossner, L. R. and Allen, E. R.: 1989, in: D. W. Ming and L. Henninger, D. L. (eds.), Lunar Base Agriculture: Soils for Plant Growth, pp. 8–105, Am. Soc. of Agronomy Press, Madison, Wisconsin. 546 ABSTRACTS OF POSTERS PRESENTED AT ISSOL ’02

Mautner, M. N., Conner, A. J., Killham, K. and Deamer, D. W.: 1997, Icarus 129, 245–253. Stoker, C. A.: 1993, The Physical and Chemical Properties and Resource Potential of Martian Surface Soils, NASA Ames Research Center Report, 659 pp.