DOCSLIB.ORG

Information to Users

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Information to Users INFORMATION TO USERS This manuscript has been reproduced from the microfilm master. UMI films the text directly from the origmal or copy submitted. Thus, some thesis and dissertation copies are in Qrpewriter fitce, while others may be from any type of computer printer. The quality of this reproduction is dependent npon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough, substandard margins, and improper alignment can adversety affect reproduction. In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the ddetioiL Oversize materials (e.g., maps, drawings, charts) are reproduced by sectioning the original, beginning at the upper left-hand comer and continuing from left to right in equal sections with small overlaps. Each original is also photographed in one exposure and is included in reduced form at the back of the book. Photographs included in the original manuscript have been reproduced xerographically in this copy. Higher quality 6” x 9” black and white photographic prints are available for any photographs or illustrations spearing in this copy fiar an additional charge. Contact UMI directly to order. UMI A Bell & Hiowellliafinniation Compai^ 300 North Zoào Road, Ann Arbor MI 48106-1346 USA 313/761-4700 800/521-0600 ASSIMILATION OF SYMBIOTICALLY-REDUŒD NITROGEN IN TROPICAL LEGUMES: REGULATION OF PEROXISOME PROLIFERATION AND UREIDE PRODUCTION DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in the Graduate School of The Ohio State University by Tianyun Wu, B.S., M S. ***** The Ohio State University 1998 Dissertation Committee: Approved by Profesor Desh-Pal S. Verma, Adviser Professor Keith R. Davis Professor Terrence L. Graham Adviser Department of Plant Pathology UMI Number: 9822389 UMI Microform 9822389 Copyright 1998, by UMI Company. Ail rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. UMI 300 North Zeeb Road Ann Arbor, MI 48103 ABSTRACT Peroxisomes are specialized subcellular organelles existing in all eukaryotic organisms, which carry out diverse metabolic roles essential for living cells. Plant peroxisomes have long been known to be involved in mobilization of storage oil reserves, synthesis of ureides and salvage of photorespiratory phosphoglycolate. In root nodules of tropical legumes, the de novo purine biosynthesis pathway is induced with the onset of Nz-fixation, converting symbiotically reduced nitrogen to ureides. Peroxisomes are proliferated in root nodules in response to synthesized purines during N2-6xation as oxidation of purines requires this organelle. Using Saccharomyces cerevisiae, we demonstrated that catalase and uricase (two marker enzymes of peroxisomes) activities were induced by xanthine. This study suggested that xanthine could induce peroxisome proliferation in S. cerevisiae, but uric acid could only induce uricase activity. A strain of S. cerevisiae was mutagenized with ethyl methyl sulfonate (EMS). A positive selective procedure was used based on the lethality of H2O2 accumulation in wild-type cells with application of a catalase inhibitor, 3-amino-1,2,4-triazol. Four putative peroxisome biogenesis mutants were isolated which failed to utilize oleic acid as the sole C-source and uric acid as the sole N-source, respectively, and fell into three different complementation groups. Their peroxisomal catalase activities were less induced by oleic acid than that of the wild-type cells. One mutant (Spbl) showed a restrict phenotype of non-utilizing uric acid or oleic acid, and had a single mutation. Spbl showed less induction of peroxisomal enzymes including u uricase and catalase, which was used for complementation with a soybean nodule cDNA library constructed in LAMDA MAXI. A cDNA (spbl) encodes a DNA binding protein which contains a basic region/helix-loop-helix (bHLH) domain was isolated on oleic acid selective medium. The deduced amino acid of SPB1 contains 150 amino acids and shows less than 40% homologies with other plant bHLH containing transcription factors, e.g. phaseolin G-box binding protein, myc-like-R factor and rice transcription activator Ra. Sequence comparison revealed that SPB 1 likely represents a new member of bHLH protein family in plants, which may be involved in regulation of peroxisome proliferation in plants. The urate oxidation into allantoin by uricase is carried out within peroxisomes during the oxidative decomposition of purines. In nodule tissue, the major urate oxidation takes place through the xanthine-dehydrogenase-uricase system that is widely distributed in bacteria and animals. Previous studies have suggested that a urate degradation system composed of a peroxidase and a diamine oxidase exists in soybean radicles. The diamine oxidase catalyze the deamination of polyamines into aldehyde, ammonia and hydrogen peroxide. Cadaverine, a diamine, serves as a cofactor in this enzymes system. Therefore, the hydrogen peroxide generated from cadaverine oxidation regulates the peroxidase urate-degrading activity. By functional complementation of a yeast S. cerevisiae mutant Spbl, two soybean cDNA fragments were isolated from a soybean nodule cDNA library which encode a cytochrome P450 and a copper-containing amine oxidase, respectively. The full length clones of these two cDNAs were isolated by using the cDNA fragments as probes. P450 full length cDNA is 1.9-kilobase long and contains an open reading frame encoding a protein having 511 amino acids with a molecular weight of 67 kDa. This P450 was identified as a HiOi-dependent urate- degrading peroxidase (P450W). The full length cDNA of copper-containing amine oxidase is 2,663 base pairs long and encode a protein with 701 amino acid residues. Its m enzyme activity is highly efficient towards diamines putrecine and cadaverine. Both proteins contain a typical peroxisomal targeting signal (PSTl) near/at the C-terminus which strongly suggests that they are peroxisomal enzymes. Both P450W and soybean peroxisomal amine (SPAO) oxidase are expressed in cotyledon, root, leaf and nodule tissues, but SPAO is expressed in a very low content suggesting that it may be substrate inducible. Amino acid sequence comparison reveals that P450W and SPAO share less than 40% homology with other known P450s and copper-containing amine oxidases and form a new gene family of each superfamily, respectively. The feature of P450W implies that the mode of action as a peroxidase or a monooxygenase may be regulated by the ratio of O2/H2O2 in the compartment of peroxisomes. This study confirmed the existence of an alternate pathway for urate oxidation, and revealed a new cellular function of peroxisomes. Thus, amine oxidation and urate oxidation can be catalyzed in a diamine oxidase-peroxidase enzyme system in plant peroxisomes. This alternate pathway may contribute to nitrogen supplement and messenger molecule generation during plant growth and play an important role in cell growth, development and protection of plant against stresses. IV To my parents, and sisters, Tianling and Tianwen, who love and encourage me. ACKNOWLEDGMENTS My sincere gratitude is expressed to my great adviser. Dr. Dash-Pai S. Verma. I truly admire him the serious scientific attitude and his deep knowledgeable vision of science. He provided guidance, advise and patience and very generous contributions to both my educational and professional development. I wish to express great appreciation to my Smdent Advisory Committee member, Drs. K. R. Davis, T. L. Graham and D. Coplin, for their suggestions and comments on this study. My appreciation is particularly expressed to all persons in my Lab who have contributed to making my graduate work positive and successful. Thank for their friendship and encouragement. I give special thanks to Drs. Zonglie Hong, Chunsheng Zhang, for their patient advice and help through my research. Sincere appreciation also extended to Drs. Xiangju Gu, Jone Heon Kim and Zhaohua Peng, and Mr. 29iongming Zhang, Sunhun, Kim. Finally, I thank my friends, my parents and sisters for their enduring faith, fellowship and love. VI VTTA December 26, 1964 ...................................... Bom-Handan, Hebei Province, People's Republic of China July 1 9 8 ....................................................B.S. Microbiology, Shandong University, Jinan, Shandong, P. R. China 198 -1988 ....................................................Research Assistant, Institute of Applied Atomic Energy, Chinese Academy of Agricultural Sciences (CAAS) 1989-1991 ..................................................Research Assistant, Institute of Plant Protection, CAAS April 1991- October 1993 ............................ M. S. Graduate Fellow, Graduate Research Associate, Department of Plant Pathology, Ohio Agriculture Research and Development Center (OARDQ, The Ohio State University October 1993 -March 1994 .........................Research Assistant, Plant Biotechnology Center, The Ohio State University vii PUBLICATION 1. Boehm, M.J., Wu, T., Stone, A.G., Kraakman, B., Wilson., G. E., Maddon, L.V., and Hoitink, H.J., 1997, Cross-Polarized Magic-Angle Spinning ^^Nuclear Magnetic Resonance Spectroscopic Characterization of Sole Organic Matter Relative to Cultivable Bacterial Species Composition and Sustained Biological Control
Load more

Recommended publications
  • Cell & Molecular Biology
    BSC ZO- 102 B. Sc. I YEAR CELL & MOLECULAR BIOLOGY DEPARTMENT OF ZOOLOGY SCHOOL OF SCIENCES UTTARAKHAND OPEN UNIVERSITY BSCZO-102 Cell and Molecular Biology DEPARTMENT OF ZOOLOGY SCHOOL OF SCIENCES UTTARAKHAND OPEN UNIVERSITY Phone No. 05946-261122, 261123 Toll free No. 18001804025 Fax No. 05946-264232, E. mail [email protected] htpp://uou.ac.in Board of Studies and Programme Coordinator Board of Studies Prof. B.D.Joshi Prof. H.C.S.Bisht Retd.Prof. Department of Zoology Department of Zoology DSB Campus, Kumaun University, Gurukul Kangri, University Nainital Haridwar Prof. H.C.Tiwari Dr.N.N.Pandey Retd. Prof. & Principal Senior Scientist, Department of Zoology, Directorate of Coldwater Fisheries MB Govt.PG College (ICAR) Haldwani Nainital. Bhimtal (Nainital). Dr. Shyam S.Kunjwal Department of Zoology School of Sciences, Uttarakhand Open University Programme Coordinator Dr. Shyam S.Kunjwal Department of Zoology School of Sciences, Uttarakhand Open University Haldwani, Nainital Unit writing and Editing Editor Writer Dr.(Ms) Meenu Vats Dr.Mamtesh Kumari , Professor & Head Associate. Professor Department of Zoology, Department of Zoology DAV College,Sector-10 Govt. PG College Chandigarh-160011 Uttarkashi (Uttarakhand) Dr.Sunil Bhandari Asstt. Professor. Department of Zoology BGR Campus Pauri, HNB (Central University) Garhwal. Course Title and Code : Cell and Molecular Biology (BSCZO 102) ISBN : 978-93-85740-54-1 Copyright : Uttarakhand Open University Edition : 2017 Published By : Uttarakhand Open University, Haldwani, Nainital- 263139 Contents Course 1: Cell and Molecular Biology Course code: BSCZO102 Credit: 3 Unit Block and Unit title Page number Number Block 1 Cell Biology or Cytology 1-128 1 Cell Type : History and origin.
    [Show full text]
  • Aconitase: to Be Or Not to Be Inside Plant Glyoxysomes, That Is the Question
    biology Review Aconitase: To Be or not to Be Inside Plant Glyoxysomes, That Is the Question Luigi De Bellis 1,* , Andrea Luvisi 1 and Amedeo Alpi 2 1 Department of Biological and Environmental Sciences and Technologies, University of Salento, Via Prov. le Monteroni, I-73100 Lecce, Italy; [email protected] 2 Approaching Research Educational Activities (A.R.E.A.) Foundation, I-56126 Pisa, Italy; [email protected] * Correspondence: [email protected] Received: 10 June 2020; Accepted: 10 July 2020; Published: 12 July 2020 Abstract: After the discovery in 1967 of plant glyoxysomes, aconitase, one the five enzymes involved in the glyoxylate cycle, was thought to be present in the organelles, and although this was found not to be the case around 25 years ago, it is still suggested in some textbooks and recent scientific articles. Genetic research (including the study of mutants and transcriptomic analysis) is becoming increasingly important in plant biology, so metabolic pathways must be presented correctly to avoid misinterpretation and the dissemination of bad science. The focus of our study is therefore aconitase, from its first localization inside the glyoxysomes to its relocation. We also examine data concerning the role of the enzyme malate dehydrogenase in the glyoxylate cycle and data of the expression of aconitase genes in Arabidopsis and other selected higher plants. We then propose a new model concerning the interaction between glyoxysomes, mitochondria and cytosol in cotyledons or endosperm during the germination of oil-rich seeds. Keywords: aconitase; malate dehydrogenase; glyoxylate cycle; glyoxysomes; peroxisomes; β-oxidation; gluconeogenesis 1. Introduction Glyoxysomes are specialized types of plant peroxisomes containing glyoxylate cycle enzymes, which participate in the conversion of lipids to sugar during the early stages of germination in oilseeds.
    [Show full text]
  • Downloads/Cobratoolbox
    UC San Diego UC San Diego Electronic Theses and Dissertations Title A stoichiometric model of Escherichia coli 's macromolecular synthesis machinery and its integration with metabolism Permalink https://escholarship.org/uc/item/1z9752m7 Author Thiele, Ines Publication Date 2009 Peer reviewed|Thesis/dissertation eScholarship.org Powered by the California Digital Library University of California UNIVERSITY OF CALIFORNIA, SAN DIEGO A stoichiometric model of Escherichia coli's macromolecular synthesis machinery and its integration with metabolism. A dissertation submitted in partial satisfaction of the requirements for the degree Doctor of Philosophy in Bioinformatics by Ines Thiele Committee in charge: Professor Bernhard Ø. Palsson, Chair Professor Steven P. Briggs, Co-Chair Professor Alexander Hoffmann Professor Milton H. Saier Professor Julian I. Schroeder 2009 Copyright Ines Thiele, 2009 All rights reserved. The dissertation of Ines Thiele is approved, and it is acceptable in quality and form for publication on microfilm and electronically: Co-Chair Chair University of California, San Diego 2009 iii DEDICATION To Renate, Steffen, Dana, and Ronan. iv TABLE OF CONTENTS Signature Page . iii Dedication . iv Table of Contents . v List of Figures . viii List of Tables . x Acknowledgements . xi Vita and Publications . xiii Abstract of the Dissertation . xv Chapter 1 Introduction to molecular systems biology . 1 1.1 Constraint-based reconstruction and analysis . 2 1.2 Basic principles underlying the constraint-ba-sed reconstruction & analysis approach . 4 1.3 Reconstruction of metabolic networks in a nutshell . 6 1.4 Mathematical characterization of network capabilities . 8 1.5 Tools for analyzing network states. 9 1.6 Preview of the dissertation . 11 Chapter 2 Escherichia coli ..............................
    [Show full text]
  • Unit of Life ] Illustrated 1
    NEET II AIIMS [UNIT OF LIFE ] ILLUSTRATED 1 UNIT III CELL : STRUCTURE AND FUNCTIONS 123-172 Chapter 8 : Cell : The Unit of Life Topic: • 8.1 What is a Cell? • Cell is the fundamental structural and functional unit of all living organisms. • Anything less than a complete structure of a cell does not ensure independent living. Like – virus • Anton Von Leeuwenhoek first saw and described a live cell. • The cell was first discovered and named by Robert Hooke in 1665. [ It looked strangely similar to cellula or small rooms which monks inhabited, thus deriving the name] • Micrographia – book written by Robert Hooke • Robert Brown discovered the nucleus. • C. Benda discovers mitochondria • G.N. RAMACHANDRAN discover of the triple helical structure of collagen • 8.2 Cell Theory o Proposer- . Matthias Schleiden, a German Botanist . Theodore Schwann, a British Zoologist . Rudolf Virchow [modifier] o Theory – . all living organisms are composed of cells and products of cells. All individual cell can perform its activity alone but they doesn’t do so, rather acts as a tissue or organ . all cells arise from pre-existing cells. o Indirect meaning – . Cell is a structural & functional unit of organism • 8.3 An Overview of Cell o Mycoplasmas, the smallest cells [0.3 μm] o Other common bacteria [3 to 5 μm] o largest isolated single cell is the egg of an ostrich o human red blood cells are about 7.0 μm in diameter o Nerve cells are some of the longest cells • Concept of o Protoplasm – organized living part of the cell surrounded by the cell membrane • Protoplasm = Animal cell – [Cell membrane + non living substance (Metaplastic body / argastic substance] o Protoplast – Organized part of the cell excluding cell wall.
    [Show full text]
  • 93Fb2b03416a8e67e3657c54d1
    Investigation of the Glyoxysome-Peroxisome Transition in Germinating Cucumber Cotyledons Using Double-label Immunoelectron Microscopy DAVID E. TITUS and WAYNE M. BECKER Department of Botany, University of Wisconsin, Madison, Wisconsin 53706. Dr. Titus' present address is Department of Tropical Public Health, Harvard School of Public Health, Boston, Massachusetts 02115. Downloaded from ABSTRACT Microbodies in the cotyledons of cucumber seedlings perform two successive metabolic functions during early postgerminative development. During the first 4 or 5 d, glyoxylate cycle enzymes accumulate in microbodies called glyoxysomes. Beginning at about day 3, light-induced activities of enzymes involved in photorespiratory glycolate metabolism accumulate rapidly in microbodies. As the cotyledonary microbodies undergo a functional jcb.rupress.org transition from glyoxysomal to peroxisomal metabolism, both sets of enzymes are present at the same time, either within two distinct populations of microbodies with different functions or within a single population of microbodies with a dual function. We have used protein A-gold immunoelectron microscopy to detect two glyoxylate cycle enzymes, isocitrate lyase (ICL) and malate synthase, and two glycolate pathway enzymes, on August 16, 2017 serine:glyoxylate aminotransferase (SGAT) and hydroxypyruvate reductase, in microbodies of transition-stage (day 4) cotyledons. Double-label immunoelectron microscopy was used to demonstrate directly the co-existence of ICL and SGAT within individual microbodies, thereby
    [Show full text]
  • Structural and Functional Characterization of Rubisco
    Dissertation zur Erlangung des Doktorgrades der Fakultät für Chemie und Pharmazie der Ludwig–Maximilians–Universität München Structural and functional characterization of Rubisco assembly chaperones Thomas Hauser aus Tübingen, Deutschland 2016 Erklärung Diese Dissertation wurde im Sinne von §7 der Promotionsordnung vom 28. November 2011 von Herrn Prof. Dr. F. Ulrich Hartl betreut. Eidesstattliche Versicherung Diese Dissertation wurde eigenständig und ohne unerlaubte Hilfe erarbeitet. München, 03.02.2016 _______________________ Thomas Hauser Dissertation eingereicht am: 25.02.2016 1. Gutachter: Prof. Dr. F. Ulrich Hartl 2. Gutachter: Prof. Dr. Jörg Nickelsen Mündliche Prüfung am 28.04.2016 Acknowledgements Acknowledgements First of all, I am very thankful to Prof. Dr. F. Ulrich Hartl and Dr. Manajit Hayer-Hartl for giving me the opportunity to conduct my PhD in their department at the Max Planck Institute of Biochemistry. This work has benefited greatly from their scientific expertise and experience together with their intellectual ability to tackle fundamental scientific questions comprehensively. Their way of approaching complex projects has shaped my idea on how to perform science. I am very greatful to Dr. Andreas Bracher for giving crucial input and collaborating on many aspects on my work conducted in the department. His extensive crystallographic expertise was of great importance during my time as a PhD student. Furthermore, I want to thank Oliver Müller-Cajar for introducing me into the field of Rubisco and supporting me with help and suggestions in the beginning of my PhD. His enthusiasm about conducting science was of great importance to me and influenced my motivation to work and live science on a day- by-day lab basis enormously.
    [Show full text]
  • Sample Questions BSC1010C Chapters 5-7 1. Which Type of Lipid
    Sample Questions BSC1010C Chapters 5-7 1. Which type of lipid is most important in biological membranes? a. oils b. fats c. wax d. phospholipids e. triglycerides 2. Which type of interaction stabilizes the alpha helix structure of proteins? a. hydrogen bonds b. nonpolar covalent bonds c. hydrophobic interactions d. ionic interactions e. polar covalent bonds 3. Which of the following statements best summarizes structural differences between DNA and RNA? a. DNA has different bases from RNA. b. RNA is a protein, while DNA is a nucleic acid. c. RNA is a double helix, but DNA is not. d. DNA is not a polymer, but RNA is. e. DNA contains a different sugar from RNA. 4. Hydrolysis is involved in which of the following? a. the digestion of polysaccharides to glucose b. synthesis of starch c. peptide bonding in proteins d. hydrogen bond formation between nucleic acids e. the hydrophylic interactions of lipids 5. What maintains the secondary structure of a protein? a. electrostatic charges b. ionic bonds c. hydrogen bonds d. disulfide bridges e. peptide bonds Figure 5.5 6. The chemical reactions illustrated in Figure 5.5 result in the formation of a. peptide bonds. b. ionic bonds. c. glycosidic bonds. d. hydrogen bonds. e. an isotope. 7. Which of the following is TRUE concerning saturated fatty acids? a. All of the below are true. b. They are usually liquid at room temperature. c. They have double bonds between the carbon atoms of the fatty acids. d. They have a higher ratio of hydrogen to carbon than unsaturated fatty acids.
    [Show full text]
  • Uniqueness of the Mechanism of Protein Import Into the Peroxisome Matrix: Transport of Folded, Co-Factor-Bound and Oligomeric Pr
    Biochimica et Biophysica Acta 1763 (2006) 1552–1564 www.elsevier.com/locate/bbamcr Review Uniqueness of the mechanism of protein import into the peroxisome matrix: Transport of folded, co-factor-bound and oligomeric proteins by shuttling receptors ⁎ Sébastien Léon a,1, Joel M. Goodman b, Suresh Subramani a, a Section of Molecular Biology, Division of Biological Sciences, University California, Room 3230 Bonner Hall, 9500 Gilman Drive, UC San Diego, La Jolla, CA 92093-0322, USA b Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9041, USA Received 19 May 2006; received in revised form 18 August 2006; accepted 23 August 2006 Available online 30 August 2006 Abstract Based on earlier suggestions that peroxisomes may have arisen from endosymbionts that later lost their DNA, it was expected that protein transport into this organelle would have parallels to systems found in other organelles of endosymbiont origin, such as mitochondria and chloroplasts. This review highlights three features of peroxisomal matrix protein import that make it unique in comparison with these other subcellular compartments - the ability of this organelle to transport folded, co-factor-bound and oligomeric proteins, the dynamics of the import receptors during the matrix protein import cycle and the existence of a peroxisomal quality-control pathway, which insures that the peroxisome membrane is cleared of cargo-free receptors. © 2006 Elsevier B.V. All rights reserved. Keywords: Peroxisomal matrix protein import; Import of folded and oligomeric protein; Shuttling receptor; Extended shuttle; Peroxisomal RADAR; Quality-control The transport of proteins across the membranes of many possible grouping focuses on whether the proteins being subcellular compartments in prokaryotes and eukaryotes has transported are in an unfolded or folded state.
    [Show full text]
  • Cell – Structure and Function MODULE - 1 Diversity and Evolution of Life
    Cell – Structure and Function MODULE - 1 Diversity and Evolution of Life 4 Notes CELL – STRUCTURE AND FUNCTION INTRODUCTION All organisms are composed of structural and functional units of life called ‘cells’. The body of some organisms like bacteria, protozoans and some algae is made up of a single cell whereas the body of higher fungi, plants and animals are composed of many cells. Human body is built of about one trillion cells. Cells vary in size and structure as they are specialized to perform different functions. But the basic components of the cell are common to all biological cells. This lesson deals with the structure common to all types of the cells. You will also learn about the kinds of cell division and the processes involved therein in this lesson. OBJECTIVES After completing this lesson, you will be able to : z justify that cell is the basic structural and functional unit of all organisms; z list the components of the cell and state cell theory; z differentiate between prokaryotic and eukaryotic cells; z differentiate between plant and animal cells; z illustrate the structure of plant and animal cells by drawing labelled diagrams; z describe the structure and functions of plasma membrane, cell wall, endoplasmic reticulum (ER), cilia, flagella, nucleus, ribosomes, mitochondria, chloroplasts, golgi body, peroxisome, glyoxysome and lysosome; z describe the general importance of the cell molecules-water, mineral ions, carbohydrates, lipids, amino acids, proteins, nucleotides, nucleic acids, enzymes, vitamins, hormones, steroids and alkaloids; z justify the need for cell division; z describe various phases of cell cycle; z explain the term karyotype and mention the karyotype analysis and its significance.
    [Show full text]
  • Requirement of the C3HC4 Zinc RING Finger of the Arabidopsis PEX10 for Photorespiration and Leaf Peroxisome Contact with Chloroplasts
    Requirement of the C3HC4 zinc RING finger of the Arabidopsis PEX10 for photorespiration and leaf peroxisome contact with chloroplasts Uwe Schumann*†, Jakob Prestele*, Henriette O’Geen‡, Robert Brueggeman§, Gerhard Wanner¶, and Christine Gietl*ʈ *Lehrstuhl fu¨r Botanik, Technische Universita¨t Mu¨ nchen, Am Hochanger 4, D-85350 Freising, Germany; ‡Genome Center, University of California, Davis, CA 95616; §Department of Crop and Soil Sciences, Washington State University, Pullman, WA 99164; and ¶Lehrstuhl fu¨r Botanik, Ludwig-Maximilian-Universita¨t, Menzinger Strasse 67, D-80638 Mu¨nchen, Germany Communicated by Diter von Wettstein, Washington State University, Pullman, WA, November 23, 2006 (received for review October 17, 2006) Plant peroxisomes perform multiple vital metabolic processes in- cluding lipid mobilization in oil-storing seeds, photorespiration, and hormone biosynthesis. Peroxisome biogenesis requires the function of peroxin (PEX) proteins, including PEX10, a C3HC4 Zn RING finger peroxisomal membrane protein. Loss of function of PEX10 causes embryo lethality at the heart stage. We investigated the function of PEX10 with conditional sublethal mutants. Four T-DNA insertion lines expressing pex10 with a dysfunctional RING finger were created in an Arabidopsis WT background (⌬Zn plants). They could be normalized by growth in an atmosphere of high CO2 partial pressure, indicating a defect in photorespiration. ␤- Oxidation in mutant glyoxysomes was not affected. However, an abnormal accumulation of the photorespiratory metabolite glyoxylate, a lowered content of carotenoids and chlorophyll a and PLANT BIOLOGY b, and a decreased quantum yield of photosystem II were detected under normal atmosphere, suggesting impaired leaf peroxisomes. Light and transmission electron microscopy demonstrated leaf Fig. 1.
    [Show full text]
  • Diphosphatase Related to Lipid Metabolism and Gluconeogenesis in Cucumber Cotyledons: Localization in Plasma Membrane and Etioplasts but Not in Glyoxysomes
    Diphosphatase Related to Lipid Metabolism and Gluconeogenesis in Cucumber Cotyledons: Localization in Plasma Membrane and Etioplasts but not in Glyoxysomes Thomas Kirsch. Barbara Rojahn, and Helmut Kindi Biochemie, FB Chemie. Philipps-Universität Marburg, D-3550 Marburg, Bundesrepublik Deutschland Z. Naturforsch. 44c, 937—945 (1989); received June 7/July 25, 1989 Plastid, Plasma Membrane, Glyoxysome, Diphosphatase (Pyrophosphatase), Cucumber Mobilization Diphosphatase (inorganic pyrophosphatase) activity was localized within compartments of cotyledons of germinating cucumber seeds during the stage of maximal conversion of fat into carbohydrates. At this stage, almost 2 mol pyrophosphate are produced during the formation of one mole sucrose from 0.28 mol triglyceride. When organelles of the 2000 xg pellet or 10,000 xg pellet were separated by density gradient centrifugation and gradient flotation, the diphosphatase activity paralleled the profiles of markers of the plastid stroma but was virtually absent from the glyoxysomes. Within the fraction of small vesicles and membranes, diphosphatase was attributed to the plasma membrane. The main portion of diphosphatase, contained in the plastids, was partially purified by chromatography on anion exchange resin and molecular sieving, leading to a 75-fold enrichment compared to the stroma fraction. Trace amounts of diphosphatase observed in the glyoxysomal fraction were analyzed in the same way. Comparison of the isoelectric points and the activity profile at different pH values and the inhibitory effect of the various cations indicated that the trace amounts of diphosphatase activity in the glyoxysome fraction represented contaminations originating from the plastids. The plasma membrane form of diphosphatase is an integral membrane protein which was solubilized with octylglucoside.
    [Show full text]
  • A Case Study of Cell Structure. 8P.; Paper Presented at the Regional Conf
    DOCUMENT RESUME ED 282 717 SE 048 140 AUTHOR Blystone, Robert V. TITLE The Value of Analysis of Standardized Placement Exams: A Case Study of Cell Structure. PUB DATE 14 Feb 87 NOTE 8p.; Paper presented at the Regional Conference on University Teaching (2nd, Las Cruces, NM, February 1987). PUB TYPE Reports - Research/Technical (143) -- Speeches/Conference Papers (150) EDRS PRICE MF01/PC01 Plus Postage. DESCRIPTORS Achievement Tests; *Advanced Placement Programs; *Biology; College Bound Students; High Schools; Science Education; *Science Tests; *Secondary School Science; *Test Interpretation; Textbook Content IDENTIFIERS *Cells (Biology); *Science Education Research ABSTRACT This study focused on potential pedagological uses of standardized placement exams. A sample of 250 exams of the May 1984 Biology Advanced Placement (AP) exam was obtained and student responses to the question on cell structure were analyzed. The frequency of particular responses to the question is listed and trends and patterns in the responses are discussed. Interviews were also conducted with AP biology instructors, high school science coordinators, readers of the 1985 AP Biology exam, college biology instructors, and professional research cell biologists for purposes of explaining the AP cell structure question results. Textbooks and resource materials were then examined for their impact on potential learnings of students and for the amount of information that they had on cell structures. Recommendations resulting from this study include: (1) provisions for additional uses of national standardized exam results other than the measurement of achievement; (2) development of hierarchically related science textbooks from high school to college; and (3) periodic replacement of learning resource materials to accompany test materials.
    [Show full text]