DOCSLIB.ORG

S0968-0004(80)

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
S0968-0004(80) 32 TIBS - February 1980 Open Question but again reduced pyridine nucleotides and What is the physiological role of ATP are consumed. It has been claimed [7] that the metabolism of glycolate fuels the photorespiration? production of mitochondrial ATP. This refers to the conversion of glycine to serine U. Heber and G. H. Krause in the mitochondria that yields NADH. hz vitro, NADH can be oxidized in the respiratory chain. In vivo, however, reduc- There is scarcely any cell that is metaboli- competes with CO2 at the active sites of ing equivalents must be reinvested for the cally more flexible than the mesophyll cell ribulose bisphosphate (RuBP) carboxyl- reduction of hydroxypyruvate and refixa- of plant leaves. Upon illumination, ase. Instead of being carboxylated, RuBP is tion of NH~ liberated during the formation respiratory oxygen uptake is rapidly oxygenated to form phosphoglycerate and of serine (Fig. 1). On balance, those reduc- replaced by photosynthetic oxygen evolu- phosphoglycolate. The latter is hydrolysed ing equivalents are therefore unavailable tion which may be up to 100 times faster to glycolate. for ATP production. Apparently the than oxygen uptake in the dark. Often, A peculiar feature of photorespiration is ammonia is not incorporated directly into mitochrondrial respiration, which gives that, in contrast to dark respiration, it does glutamate by mitochondrial glutamate rise to oxygen uptake, is suppressed in the not conserve but consumes energy [6]. This dehydrogenase, but rather is ref'Lxed by light. However, in the presence of atmos- becomes apparent from the energy balance glutamine synthetase in the cytosol or pheric concentrations of oxygen, most of the metabolic cycles depicted in Fig. 1. chloroplasts to form glutamine [8]. In the plants exhibit another type of oxidative The formation of glycolate requires energy chloroplasts, the glutamine reacts with sugar degradation that is not observed in in the form of ATP and reducing equiv- 2-oxoglutarate to glutamate. The latter the dark and is therefore called photo- alents, since it utilizes photosynthetic pathway requires, in addition to reducing respiration [1]. This process has unusual intermediates. Isolated chloroplasts can equivalents, one ATP to re-assimilate one properties. It proceeds at appreciable rates oxidize triosephosphate (TP) via RuBP molecule of NH~. The balance of the inte- only at high oxygen tensions and can there- and the Calvin cycle completely to glyco- grated cycles in the scheme in Fig. 1 shows fore be suppressed by a reduction in the late and inorganic phosphate [3]. The that evolution of 1 mol CO2 by photorespi- partial pressure of oxygen. In an atmos- energy requirement of the oxidation pro- ration re.quires about twice as much energy phere containing 1-2% oxygen, almost no cess can be derived from a summation of as assimilation of 1 mol CO, in the Calvin photorespiration is observed. the individual reactions involved, yielding: cycle [6]. It is noteworthy that the ratio of The biochemical pathway of photores- reducing equivalents consumed to ATP 2 TW- + 3 O2 + 3 NADPH + 6 ATW- piration has been elucidated mainly by consumed is the same or almost the same in + 6 OH--~ Tolbert and co-workers [2]. In brief, glyco- photorespiratory carbohydrate oxidation 3 glycolate - + 8 Pi ~- + 3 NADP ~ late is formed in the chloroplasts at the as in photosynthetic carbohydrate forma- + 6 ADP 3- + H20 expense of sugar-phosphate intermediates tion. Clearly, energy-dependent oxidation of the Calvin cycle. After export from the Details of the conversion of glycolate to instead of formation of carbohydrates must chloroplasts, the glycolate undergoes a phosphoglycerate are not entirely clear, reduce photosynthetic yield. series of reactions taking place in peroxi- somes, mitochondria and finally again in II CHLOROPLAST II OUTSIDEOF CHLOROPLAST the chloroplasts (Fig. 1). There, phospho- II glycerate is produced, linking glycolate II ATP II metabolism to the Calvin cycle. Formation II and conversion of 2 mol of glycolate to 1 II t P-glyiolote 11 mol of phosphoglycerate lead to the uptake glycolate II of 3 mol O2 and the evolution of 1 mol CO2. IIII , glyc~ If photosynthetic oxygen evolution for II glyoxylote production of requii'ed reducing equiv- II alents is taken into account, an O~/CO2 triose-P II II [ ratio of 1 is obtained for the complete pro- II cess of photorespiration. The key reaction | Calvin cycle ) II -iHz gl~~'-IH]P 171 II of the process - the biosynthesis of glyco- II late in the chloroplasts - has been a con- II 5n/o._ O II troversial issue for several years. It now U pyruvote [~1 appears established [3-5] that .oxygen II 13-ph0 +yc.ro,. glycr~'~'otee 1 ATP NADPH U. Heber and G. tl. Krattse are at the Institute of II Botany and Pharrnaceutical Biology of the University II of Wgtrzburg and Institute of Botany of the University Fig. I. Scl, eme of photosynthetic and photorespiratory pathways showing energy-requiring steps. [It] denotes of Diisseldorf, F.R.G. reduced pyridine nucleotide. * Phosphorylation of glycerate is possible both inside and outside the chloroplasts. El~vier/North-HollandBiomedical Prr 1980 TIBS - February 1980 33 Bjfrkman [12] have suggested that photo- respiratory energy consumption may pro- tect plants from photo-oxidative damage. l | Several mechanisms are available to pre-~ vent light damage to the photosynthetic apparatus [13]. Carotenoids are known to play a role in the protection of chloroplast - - ~-- l rnin, ~(~ L.-..-....~._.~ pigments against photo-bleaching. Super- I' light on oxide dismutase, catalase, ascorbate and glutathione act together to degrade oir. oil. superoxide radicals and hydrogen peroxide Fig. 2. Effects o f gas phase composition on scattering o f a weak beam of 535 nm light by a spinach leaf.. Exciting red formed during reduction of oxygen. It light (intensity 125 W.m=) was switched on aj~er a 2 rain dark period. The gas phase surrounding the leaf was appeared possible that light energy not changed from air to nitrogen and vice versa, both containing 475 ppm C02. Numbers denote steady-state rates of used for photosynthesis could give rise to net photosynthetic CO~ uptake, as recorded with an infrared analyser (hoT,oiling chlorophyll h). destructive reactions which cannot be Dissipation of energy by photores- photorespiration would only be practical handled by the available protective piration can be demonstrated in vivo by when oxygenation of RuBP is selectively deVices. light scattering chlorophyll fluorescence suppressed without the impairment of Attempts have been made to test this measurements [6]. Upon illumination of carboxylase activity, a task that seems dif- concept. Isolated chloroplasts that are cap- leaves, a proton gradient is established ficult to accomplish. able of photosynthetic rates comparable to across the energy-conserving thylakoid There is the question of why evolu- those shown by the parent leaves were membranes in the chloroplasts. Together tionary pressures have not eliminated a exposed to light in the absence of CO2 [14]. with a light-dependent membrane poten- process as wasteful as photorespiration Oxidizable substrates were also largely tial this is thought to drive ATP synthesis. appears to be. Such pressures seem to have absent from the chloroplasts and little for- The magnitude of the proton gradient can produced insensitivity to oxygen inhibition mation of glycolate was possible during be used as a measure of the energization of of photosynthesis in the group of'Ca plants' illumination. Within only a few minutes of the chloroplast system. Formation of the in which primary photosynthetic CO2 exposure to light, the chloroplasts lost a proton gradient gives rise to an increase jn incorporation occurs into the Ca acid, significant proportion of their capacity to light scattering and a decrease in chloro- oxaloacetate. Even Ca plants are capable of photoreduce CO= (Table I). This loss of phyll fluorescence. Both phenomena'can photorespiration, but photorespiratory activity was irreversible. It seems that in be easily monitored in intact leaves. Fig. 2 rates are low. The rates are probably these chloroplasts, photophosphorylation shows that after a lag phase during which a decreased because Ca plants have a and, to a lesser degree, photosynthetic steady rate of photosynthesis and mechanism whereby CO2 is accumulated at electron transport were partly inactivated. photorespiration in air are established, the site of secondary CO= fixation by RuBP Oxygen appeared to play a role in the inac- light scattering by a leaf is kept at a low carboxylase. In isolated chloroplasts from tivation, as damage increased with increas- value. When photorespiration is suppres- spinach, a (23 plant, glycolate synthesis is ing oxygen concentration. Chloroplasts sed by exchange of air for Na + CO2, light almost completely suppressed by CO2 permitted to assimilate CO2 during illumi- scattering increases, indicating increased [3,4]. In leaves of (23 plants, the ratio of nation at a constant oxygen concentration energization of the membranes. This sup- CO= fixation to photorespiratory CO2 did not lose activity while exposed to light. ports a higher rate of CO2 f'Lxation; energy evolution increases with ambient CO2 con- Rather similar results were obtained that in air was required for photorespirat- centrations, although in apparent contra- with isolated leaf cells suspended in CO2- ory COa evolution is now available for diction to the results found hz vitro, absol- and bicarbonate-free
Load more

Recommended publications
  • Biomolecules
    CHAPTER 3 Biomolecules 3.1 Carbohydrates In the previous chapter you have learnt about the cell and 3.2 Fatty Acids and its organelles. Each organelle has distinct structure and Lipids therefore performs different function. For example, cell membrane is made up of lipids and proteins. Cell wall is 3.3 Amino Acids made up of carbohydrates. Chromosomes are made up of 3.4 Protein Structure protein and nucleic acid, i.e., DNA and ribosomes are made 3.5 Nucleic Acids up of protein and nucleic acids, i.e., RNA. These ingredients of cellular organelles are also called macromolecules or biomolecules. There are four major types of biomolecules— carbohydrates, proteins, lipids and nucleic acids. Apart from being structural entities of the cell, these biomolecules play important functions in cellular processes. In this chapter you will study the structure and functions of these biomolecules. 3.1 CARBOHYDRATES Carbohydrates are one of the most abundant classes of biomolecules in nature and found widely distributed in all life forms. Chemically, they are aldehyde and ketone derivatives of the polyhydric alcohols. Major role of carbohydrates in living organisms is to function as a primary source of energy. These molecules also serve as energy stores, 2021-22 Chapter 3 Carbohydrade Final 30.018.2018.indd 50 11/14/2019 10:11:16 AM 51 BIOMOLECULES metabolic intermediates, and one of the major components of bacterial and plant cell wall. Also, these are part of DNA and RNA, which you will study later in this chapter. The cell walls of bacteria and plants are made up of polymers of carbohydrates.
    [Show full text]
  • Sugars As the Source of Energized Carbon for Abiogenesis
    Astrobiology Science Conference 2010 (2010) 5095.pdf SUGARS AS THE SOURCE OF ENERGIZED CARBON FOR ABIOGENESIS. A. L. Weber, SETI Institute, NASA Ames Research Center, Mail Stop 239-4, Moffett Field, CA, 94035-1000, [email protected] Abstract: As shown in Figure 1, abiogenesis has sev- eral requirements: (A) a source of organic substrates and chemical energy that drives the synthesis of (B) useful small molecules (ammonia, monomers, metabo- lites, energy molecules), and (C) a second synthetic processs that yields large replicating and catalytic polymers that control (D) the growth and maintenance of a primitive protocell. Furthermore, the required chemical energy must be sustained and effectively coupled to individual reactions to drive biosynthesis at a rate that counters chemical degradation. Energy coupling would have been especially difficult during the origin of life before the development of powerful enzyme catalysts with 3-D active sites. To solve this energy coupling problem we have investigated abio- genesis using sugar substrates whose energized carbon groups drive spontaneous synthetic self-transformation reactions that yield: biometabolites, catalytic mole- cules, energy-rich thioesters, amino acids, plausible alternative nucleobases and cell-like microstructures [1-8]. Recently, we demonstrated that sugars drive the synthesis of ammonia from nitrite [9]. The ability of sugars to drive ammonia synthesis provides a way to generate ammonia at microscopic sites of sugar-based origins processes, thereby eliminating the need for a planet-wide source of photochemically unstable am- monia. Figure 1. Major Synthetic Processes of Abiogenesis. [1] Weber A. L. (1998) Orig. Life Evol. Biosph., 28, 259-270. [2] Weber A.
    [Show full text]
  • An Overview of Biosynthesis Pathways – Inspiration for Pharmaceutical and Agrochemical Discovery
    An Overview of Biosynthesis Pathways – Inspiration for Pharmaceutical and Agrochemical Discovery Alan C. Spivey [email protected] 19th Oct 2019 Lessons in Synthesis - Azadirachtin • Azadirachtin is a potent insect anti-feedant from the Indian neem tree: – exact biogenesis unknown but certainly via steroid modification: O MeO C OAc O 2 H O OH O H O OH 12 O O C 11 O 14 OH oxidative 8 O H 7 cleavage highly hindered C-C bond HO OH AcO OH AcO OH for synthesis! H H of C ring H MeO2C O AcO H tirucallol azadirachtanin A azadirachtin (cf. lanosterol) (a limanoid = tetra-nor-triterpenoid) – Intense synhtetic efforts by the groups of Nicolaou, Watanabe, Ley and others since structural elucidation in 1987. –1st total synthesis achieved in 2007 by Ley following 22 yrs of effort – ~40 researchers and over 100 person-years of research! – 64-step synthesis – Veitch Angew. Chem. Int. Ed. 2007, 46, 7629 (DOI) & Veitch Angew. Chem. Int. Ed. 2007, 46, 7633 (DOI) – Review ‘The azadirachtin story’ see: Veitch Angew. Chem. Int. Ed. 2008, 47, 9402 (DOI) Format & Scope of Presentation • Metabolism & Biosynthesis – some definitions, 1° & 2° metabolites • Shikimate Metabolites – photosynthesis & glycolysis → shikimate formation → shikimate metabolites – Glyphosate – a non-selective herbicide • Alkaloids – acetylCoA & the citric acid cycle → -amino acids → alkaloids – Opioids – powerful pain killers • Fatty Acids and Polyketides –acetylCoA → malonylCoA → fatty acids, prostaglandins, polyketides, macrolide antibiotics – NSAIDs – anti-inflammatory’s • Isoprenoids/terpenes
    [Show full text]
  • Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight
    Received: 26 November 2018 Revised: 29 January 2019 Accepted: 31 January 2019 DOI: 10.1002/rcm.8406 RESEARCH ARTICLE Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry analysis for characterization of lignin oligomers using cationization techniques and 2,5‐dihydroxyacetophenone (DHAP) matrix Amber S. Bowman | Shardrack O. Asare | Bert C. Lynn Department of Chemistry, University of Rationale: Effective analytical techniques are needed to characterize lignin Kentucky, Lexington, KY 40506, USA products for the generation of renewable carbon sources. Application of matrix‐ Correspondence assisted laser desorption/ionization (MALDI) in lignin analysis is limited because of Bert C. Lynn, Department of Chemistry, UK Mass Spectrometry Facility, University of poor ionization efficiency. In this study, we explored the potential of cationization Kentucky, A053 ASTeCC Building, Lexington, along with a 2,5‐dihydroxyacetophenone (DHAP) matrix to characterize model KY 40506‐0286, USA. Email: [email protected] lignin oligomers. Funding information Methods: Synthesized lignin oligomers were analyzed using the developed MALDI National Science Foundation, Grant/Award method. Two matrix systems, DHAP and α‐cyano‐4‐hydroxycinnamic acid (CHCA), Number: OIA 1632854 and three cations (lithium, sodium, silver) were evaluated using a Bruker UltraFlextreme time‐of‐flight mass spectrometer. Instrumental parameters, cation concentration, matrix, sample concentrations, and sample spotting protocols were optimized for improved results. Results: The DHAP/Li+ combination was effective for dimer analysis as lithium adducts. Spectra from DHP and ferric chloride oligomers showed improved signal intensities up to decamers (m/z 1823 for the FeCl3 system) and provided insights into differences in the oligomerization mechanism. Spectra from a mixed DHP oligomer system containing H, G, and S units showed contributions from all monolignols within an oligomer level (e.g.
    [Show full text]
  • Bioinorganic Chemistry Content
    Bioinorganic Chemistry Content 1. What is bioinorganic chemistry? 2. Evolution of elements 3. Elements and molecules of life 4. Phylogeny 5. Metals in biochemistry 6. Ligands in biochemistry 7. Principals of coordination chemistry 8. Properties of bio molecules 9. Biochemistry of main group elements 10. Biochemistry of transition metals 11. Biochemistry of lanthanides and actinides 12. Modell complexes 13. Analytical methods in bioinorganic 14. Applications areas of bioinorganic chemistry "Simplicity is the ultimate sophistication" Leonardo Da Vinci Bioinorganic Chemistry Slide 1 Prof. Dr. Thomas Jüstel Literature • C. Elschenbroich, A. Salzer, Organometallchemie, 2. Auflage, Teubner, 1988 • S.J. Lippard, J.N. Berg, Bioinorganic Chemistry, Spektrum Akademischer Verlag, 1995 • J.E. Huheey, E. Keiter, R. Keiter, Anorganische Chemie – Prinzipien von Struktur und Reaktivität, 3. Auflage, Walter de Gruyter, 2003 • W. Kaim, B. Schwederski: Bioinorganic Chemistry, 4. Auflage, Vieweg-Teubner, 2005 • H. Rauchfuß, Chemische Evolution und der Ursprung des Lebens, Springer, 2005 • A.F. Hollemann, N. Wiberg, Lehrbuch der Anorganischen Chemie, 102. Auflage, de Gruyter, 2007 • I. Bertini, H.B. Gray, E.I. Stiefel, J.S. Valentine, Biological Chemistry, University Science Books, 2007 • N. Metzler-Nolte, U. Schatzschneier, Bioinorganic Chemistry: A Practical Course, Walter de Gruyter, 2009 • W. Ternes, Biochemie der Elemente, Springer, 2013 • D. Rabinovich, Bioinorganic Chemistry, Walter de Gruyter, 2020 Bioinorganic Chemistry Slide 2 Prof. Dr. Thomas Jüstel 1. What is Bioinorganic Chemistry? A Highly Interdisciplinary Science at the Verge of Biology, Chemistry, Physics, and Medicine Biochemistry Inorganic Chemistry (Micro)- Physics & Biology Spectroscopy Bioinorganic Chemistry Pharmacy & Medicine & Toxicology Physiology Diagnostics Bioinorganic Chemistry Slide 3 Prof. Dr. Thomas Jüstel 2. Evolution of the Elements Most Abundant Elements in the Universe According to Atomic Fraction Are: 1.
    [Show full text]
  • Synthesis and Biosynthesis of Polyketide Natural Products
    Syracuse University SURFACE Chemistry - Dissertations College of Arts and Sciences 12-2011 Synthesis and Biosynthesis of Polyketide Natural Products Atahualpa Pinto Syracuse University Follow this and additional works at: https://surface.syr.edu/che_etd Part of the Chemistry Commons Recommended Citation Pinto, Atahualpa, "Synthesis and Biosynthesis of Polyketide Natural Products" (2011). Chemistry - Dissertations. 181. https://surface.syr.edu/che_etd/181 This Dissertation is brought to you for free and open access by the College of Arts and Sciences at SURFACE. It has been accepted for inclusion in Chemistry - Dissertations by an authorized administrator of SURFACE. For more information, please contact [email protected]. Abstract Traditionally separate disciplines of a large and broad chemical spectrum, synthetic organic chemistry and biochemistry have found in the last two decades a fertile common ground in the area pertaining to the biosynthesis of natural products. Both disciplines remain indispensable in providing unique solutions on numerous questions populating the field. Our contributions to this interdisciplinary pursuit have been confined to the biosynthesis of polyketides, a therapeutically and structurally diverse class of natural products, where we employed both synthetic chemistry and biochemical techniques to validate complex metabolic processes. One such example pertained to the uncertainty surrounding the regiochemistry of dehydration and cyclization in the biosynthetic pathway of the marine polyketide spiculoic acid A. The molecule's key intramolecular cyclization was proposed to occur through a linear chain containing an abnormally dehydrated polyene system. We synthesized a putative advanced polyketide intermediate and tested its viability to undergo a mild chemical transformation to spiculoic acid A. In addition, we applied a synthetic and biochemical approach to elucidate the biosynthetic details of thioesterase-catalyzed macrocyclizations in polyketide natural products.
    [Show full text]
  • A Unified Approach for the Enantioselective Synthesis of the Brominated Chamigrene Sesquiterpenes
    Author Manuscript Title: A Unified Approach for the Enantioselective Synthesis of the Brominated Cha- migrene Sesquiterpenes Authors: Alexander J. Burckle; Vasil H. Vasilev; Noah Burns This is the author manuscript accepted for publication and has undergone full peer review but has not been through the copyediting, typesetting, pagination and proofrea- ding process, which may lead to differences between this version and the Version of Record. To be cited as: 10.1002/anie.201605722 Link to VoR: http://dx.doi.org/10.1002/anie.201605722 COMMUNICATION A Unified Approach for the Enantioselective Synthesis of the Brominated Chamigrene Sesquiterpenes Alexander J. Burckle, Vasil H. Vasilev, and Noah Z. Burns* Abstract: The brominated chamigrene sesquiterpenes constitute a representative of the simplest members of the brominated large subclass of bromocyclohexane containing natural products, yet chamigrenes, specifically its isomeric natural product no general enantioselective strategy for the synthesis of these small counterparts, bromochamigrene[3,10,11] (3 and 4, molecules exists. Herein we report a general strategy for accessing Figure 1b). We thus devised a strategy that was capable of this family of secondary metabolites including the enantioselective providing facile access to numerous brominated spirodienes in synthesis of ()-- and ()-ent--bromochamigrene, ()-dactylone, enantioenriched form. and ()-aplydactone. Access to these molecules is enabled by a stereospecific bromopolyene cyclization initiated by the solvolysis of an enantioenriched vicinal bromochloride. Of the roughly 300 natural products that have been isolated and structurally characterized containing a bromocyclohexane motif (1, Figure 1a),[1a-c] more than 50 are represented by the brominated chamigrene sesquiterpenes (2, Figure 1a). Most members of this family differ in their level of saturation, halogenation, and oxygenation (3–8, Figure 1b).
    [Show full text]
  • And Even-Length, Medium-Chain Fatty Acids in Plants (Amino Adds/Elongtin) ANTOANETA B
    Proc. Nadl. Acad. Sci. USA Vol. 91, pp. 11437-11441, November 1994 Biochemistry A pathway for the biosynthesis of straight and branched, odd- and even-length, medium-chain fatty acids in plants (amino adds/elongtin) ANTOANETA B. KROUMOVA, ZHIYI XIE, AND GEORGE J. WAGNER* Plant Physiology/Biochemistry/Molecular Biology Program, Agronomy Department, University of Kentucky, Lexington, KY 40546-0091 Communicated by Martin Gibbs, July 25, 1994 ABSTRACT Pathways and enzymes offatty acid synthase- and even-length scFAs are synthesized via modified mediated, long-even-chain (generally C16-C20) fatty add syn- branched-chain amino acid (bcAA) metabolism in tobacco thesis are well studied, and general metabolism involved in trichome glands (6, 7). It is possible that at least branched and short-chain (Cs-C7) fatty acid biosynthesis is also understood. odd-length mcFAs are formed in this tissue similarly. Alter- In contrast, mechanism of medinm-chain (C#-C14) fatty acid natively, primers derived from bcAA metabolism may be synthesis are unclear. Recent work suggests involvement of elongated by fatty acid synthase (FAS), as suggested for chain-elongation-terminating thloesterases in medium-chain tomato trichomes (8) and tobacco epidermis (9). fatty acid formation in oilseeds and animals. We have shown The classical pathway for bcAA (Val, Leu, Ileu) biosyn- that iso- and anteiso-branched and straigbt, odd- and even- thesis in microorganisms (and largely by inference in plants, length, short-chain fatty adds esterifled in plant-trichome- ref. 10) is shown in the shaded areas of Fig. 1. Key activities gland-produced sucrose esters are synthesized by using carbon involved in branched-chain formation (reactions 1, 1A, and 2) skeletons provided by modified branched-chain amino acid are those catalyzing leucine biosynthesis in all organisms and metabolism/catablis.
    [Show full text]
  • Spontaneous Generation & Origin of Life Concepts from Antiquity to The
    SIMB News News magazine of the Society for Industrial Microbiology and Biotechnology April/May/June 2019 V.69 N.2 • www.simbhq.org Spontaneous Generation & Origin of Life Concepts from Antiquity to the Present :ŽƵƌŶĂůŽĨ/ŶĚƵƐƚƌŝĂůDŝĐƌŽďŝŽůŽŐLJΘŝŽƚĞĐŚŶŽůŽŐLJ Impact Factor 3.103 The Journal of Industrial Microbiology and Biotechnology is an international journal which publishes papers in metabolic engineering & synthetic biology; biocatalysis; fermentation & cell culture; natural products discovery & biosynthesis; bioenergy/biofuels/biochemicals; environmental microbiology; biotechnology methods; applied genomics & systems biotechnology; and food biotechnology & probiotics Editor-in-Chief Ramon Gonzalez, University of South Florida, Tampa FL, USA Editors Special Issue ^LJŶƚŚĞƚŝĐŝŽůŽŐLJ; July 2018 S. Bagley, Michigan Tech, Houghton, MI, USA R. H. Baltz, CognoGen Biotech. Consult., Sarasota, FL, USA Impact Factor 3.500 T. W. Jeffries, University of Wisconsin, Madison, WI, USA 3.000 T. D. Leathers, USDA ARS, Peoria, IL, USA 2.500 M. J. López López, University of Almeria, Almeria, Spain C. D. Maranas, Pennsylvania State Univ., Univ. Park, PA, USA 2.000 2.505 2.439 2.745 2.810 3.103 S. Park, UNIST, Ulsan, Korea 1.500 J. L. Revuelta, University of Salamanca, Salamanca, Spain 1.000 B. Shen, Scripps Research Institute, Jupiter, FL, USA 500 D. K. Solaiman, USDA ARS, Wyndmoor, PA, USA Y. Tang, University of California, Los Angeles, CA, USA E. J. Vandamme, Ghent University, Ghent, Belgium H. Zhao, University of Illinois, Urbana, IL, USA 10 Most Cited Articles Published in 2016 (Data from Web of Science: October 15, 2018) Senior Author(s) Title Citations L. Katz, R. Baltz Natural product discovery: past, present, and future 103 Genetic manipulation of secondary metabolite biosynthesis for improved production in Streptomyces and R.
    [Show full text]
  • Methyltransferases of Gentamicin Biosynthesis
    Methyltransferases of gentamicin biosynthesis Sicong Lia,1, Junhong Guoa,1, Anna Revab, Fanglu Huangb, Binbin Xionga, Yuanzhen Liua, Zixin Denga,c, Peter F. Leadlayb,2, and Yuhui Suna,2 aKey Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, People’s Republic of China; bDepartment of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom; and cState Key Laboratory of Microbial Metabolism, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, People’s Republic of China Edited by Caroline S. Harwood, University of Washington, Seattle, WA, and approved December 26, 2017 (received for review June 30, 2017) Gentamicin C complex from Micromonospora echinospora re- G418 (5) to gentamicin components C2a, C2, and C1. The mains a globally important antibiotic, and there is revived in- full mechanistic details of the subsequent transamination and terest in the semisynthesis of analogs that might show improved dehydroxylation steps remain to be clarified, although the de- therapeutic properties. The complex consists of five compo- hydrogenase GenQ (20), phosphotransferase GenP, and the nents differing in their methylation pattern at one or more sites pyridoxal-dependent enzymes GenB1, GenB2, GenB3, and in the molecule. We show here, using specific gene deletion and GenB4 have all been implicated in this enigmatic process (20, 25, chemical complementation, that the gentamicin pathway up to 26). Finally, the terminal step in both branches of the pathway the branch point is defined by the selectivity of the methyl- involves the (partial) conversion of C1a into C2b and of C2 transferases GenN, GenD1, and GenK.
    [Show full text]
  • AP Biology Life’S Beginning on Earth According to Scientific Findings (Associated Learning Objectives: 1.9, 1.10, 1.11, 1.12, 1.27, 1.28, 1.29, 1.30, 1.31, and 1.32)
    AP Auburn University AP Summer Institute BIOLOGYJuly 11-14, 2016 AP Biology Life’s beginning on Earth according to scientific findings (Associated Learning Objectives: 1.9, 1.10, 1.11, 1.12, 1.27, 1.28, 1.29, 1.30, 1.31, and 1.32) I. The four steps necessary for life to emerge on Earth. (This is according to accepted scientific evidence.) A. First: An abiotic (non-living) synthesis of Amino Acids and Nucleic Acids must occur. 1. The RNA molecule is believed to have evolved first. It is not as molecularly stable as DNA though. 2. The Nucleic Acids (DNA or RNA) are essential for storing, retrieving, or conveying by inheritance molecular information on constructing the components of living cells.. 3. The Amino Acids, the building blocks of proteins, are needed to construct the “work horse” molecules of a cell. a. The majority of a cell or organism, in biomass (dry weight of an organism), is mostly protein. B. Second: Monomers must be able to join together to form more complex polymers using energy that is obtained from the surrounding environment. 1. Seen in monosaccharides (simple sugars) making polysaccharides (For energy storage or cell walls of plants.) 2. Seen in the making of phospholipids for cell membranes. 3. Seen in the making of messenger RNA used in making proteins using Amino Acids. 4. Seen in making chromosomes out of strings of DNA molecules. (For information storage.) C. Third: The RNA/DNA molecules form and gain the ability to reproduce and stabilize by using chemical bonds and complimentary bonding.
    [Show full text]
  • Plant Sulphur Metabolism Is Stimulated by Photorespiration
    ARTICLE https://doi.org/10.1038/s42003-019-0616-y OPEN Plant sulphur metabolism is stimulated by photorespiration Cyril Abadie1,2 & Guillaume Tcherkez 1* 1234567890():,; Intense efforts have been devoted to describe the biochemical pathway of plant sulphur (S) assimilation from sulphate. However, essential information on metabolic regulation of S assimilation is still lacking, such as possible interactions between S assimilation, photo- synthesis and photorespiration. In particular, does S assimilation scale with photosynthesis thus ensuring sufficient S provision for amino acids synthesis? This lack of knowledge is problematic because optimization of photosynthesis is a common target of crop breeding and furthermore, photosynthesis is stimulated by the inexorable increase in atmospheric CO2. Here, we used high-resolution 33S and 13C tracing technology with NMR and LC-MS to access direct measurement of metabolic fluxes in S assimilation, when photosynthesis and photorespiration are varied via the gaseous composition of the atmosphere (CO2,O2). We show that S assimilation is stimulated by photorespiratory metabolism and therefore, large photosynthetic fluxes appear to be detrimental to plant cell sulphur nutrition. 1 Research School of Biology, Australian National University, Canberra, ACT 2601, Australia. 2Present address: IRHS (Institut de Recherche en Horticulture et Semences), UMR 1345, INRA, Agrocampus-Ouest, Université d’Angers, SFR 4207 QuaSaV, 49071 Angers, Beaucouzé, France. *email: guillaume. [email protected] COMMUNICATIONS BIOLOGY
    [Show full text]