DOCSLIB.ORG

Molecular Mechanisms for Regulating Seed Amino Acid Levels in Maize (Zea Mays) Marie Adams Hasenstein Iowa State University

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Molecular Mechanisms for Regulating Seed Amino Acid Levels in Maize (Zea Mays) Marie Adams Hasenstein Iowa State University Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 2007 Molecular mechanisms for regulating seed amino acid levels in maize (Zea mays) Marie Adams Hasenstein Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Agricultural Science Commons, Agronomy and Crop Sciences Commons, and the Genetics and Genomics Commons Recommended Citation Hasenstein, Marie Adams, "Molecular mechanisms for regulating seed amino acid levels in maize (Zea mays)" (2007). Retrospective Theses and Dissertations. 14677. https://lib.dr.iastate.edu/rtd/14677 This Thesis is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. Molecular mechanisms for regulating seed amino acid levels in maize (Zea mays) by Marie Adams Hasenstein A thesis submitted to the graduate faculty in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Major: Genetics Program of Study Committee: Paul Scott, Co-Major Professor Erik Vollbrecht, Co-Major Professor Phil Becraft Iowa State University Ames, Iowa 2007 Copyright © Marie Adams Hasenstein, 2007. All rights reserved. UMI Number: 1447529 UMI Microform 1447529 Copyright 2008 by ProQuest Information and Learning Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. ProQuest Information and Learning Company 300 North Zeeb Road P.O. Box 1346 Ann Arbor, MI 48106-1346 ii TABLE OF CONTENTS ACKNOWLEDGEMENTS .................................................................................................. iii ABSTRACT ............................................................................................................................ iv CHAPTER 1: GENERAL INTRODUCTION ..................................................................... 1 OBJECTIVE ............................................................................................................................. 1 DISSERTATION ORGANIZATION .............................................................................................. 2 LITERATURE REVIEW ............................................................................................................. 3 Importance of Maize for Food/Feed ................................................................................. 3 Lysine ................................................................................................................................ 4 Methionine ...................................................................................................................... 18 REFERENCES ........................................................................................................................ 26 CHAPTER 2: MOLECULAR CHARACTERIZATION OF ZMBZIP1, A DOWNSTREAM TARGET OF THE OPAQUE-2 TRANSCRIPTION FACTOR ....... 35 ABSTRACT ........................................................................................................................... 35 MATERIALS AND METHODS ................................................................................................. 36 ZmbZIP1 Expression Levels ........................................................................................... 36 Physical Mapping of the ZmbZIP1 Gene ........................................................................ 39 Creation of a ZmbZIP1 TILLING Mutant to Attempt to Alter ZmbZIP1 Protein Expression ....................................................................................................................... 41 DNA Isolation ................................................................................................................. 41 RESULTS AND DISCUSSION ................................................................................................... 46 ZmbZIP1 Has Varying Transcript Levels in Different Tissues ....................................... 46 Physical Mapping of the ZmbZIP1 Locus ....................................................................... 52 SNaPshot Genotyping ..................................................................................................... 57 CONCLUSION ........................................................................................................................ 59 REFERENCES ........................................................................................................................ 60 CHAPTER 3: MOLECULAR MECHANISM OF METHIONINE DIFFERENTIATION IN THE BS11 HIGH AND LOW MET MAIZE LINES ............ 62 ABSTRACT ........................................................................................................................... 62 MATERIALS AND METHODS ................................................................................................. 62 Differential Expression of Cys2 and Dzs10 via Quantitative Real-Time RT-PCR ......... 64 Cys2 and Dzs10 Sequencing and Allele Comparison ..................................................... 65 Amino Acid Assay to Determine Kernel Methionine Levels ........................................... 66 RESULTS AND DISCUSSION ................................................................................................... 67 The BS11HM Population Contains Significantly More Methionine than BS11LM ....... 67 Correlation Between Population Methionine Levels and Cys2 or Dzs10 mRNA Levels 69 Correlation Between Kernel Methionine and Cys2 or Dzs10 Haplotypes ..................... 73 CONCLUSION ........................................................................................................................ 76 REFERENCES ........................................................................................................................ 78 GENERAL CONCLUSIONS .............................................................................................. 79 iii ACKNOWLEDGEMENTS I would like to express my gratitude to a number of people who have been indispensible to me during my graduate career. First, to Dr. Paul Scott, my major professor, for his supervision, encouragement and enthusiasm for the work that I was doing, as well as for our many discussions on statistical analysis. I would also like to thank my committee members Drs. Erik Vollbrecht and Phil Becraft for their guidance, concern about my research, and availability throughout my time at Iowa State. Special thanks are extended to Anastasia Bodnar and Dr. Adrienne Moran-Lauter for their help with HPLC and amino acid analysis, both of which were instrumental for the completion of my project. On a more personal level, I would like to thank my husband, Jason Hasenstein, for his constant support through both my best and worst days, and to Bart and Michelle Adams, Lisa Haney, Jamie O’Rourke, Oliver Couture, and Ryan Benson for their friendship and calming and positive influences on me as I was completing my research. iv ABSTRACT The majority of worldwide maize production is used for food or feed; as such it is imperative that its amino acid balance mirror the needs of humans and animals. However, lysine and methionine, two essential amino acids necessary for proper growth and development, are lacking in the maize endosperm. In this thesis, molecular mechanisms to increase both lysine and methionine deposition in the kernel are explored. ZmbZIP1, a maize transcription factor, was identified through differential expression in a microarray experiment as a potential candidate to increase the lysine content of the endosperm while lessening the pleiotrophic effects of prior candidates, such as Opaque-2; however, RT-PCR shows this level of differential expression may be genotype specific. ZmbZIP1 was physically mapped to maize chromosome 9, contig 380, and a rice orthologue, RISBZ5 was found through synteny. Expression data shows that ZmbZIP1 mRNA is present in all tested maize tissues to some extent. An attempt to make a ZmbZIP1 knock- down/knock-out mutant did not result in any phenotypic changes in the maize plant as a whole. Further no changes were seen in kernel alpha-zein deposition, which is the main determinant of endosperm lysine content. These results suggest either a functionally redundant protein to ZmbZIP1 exists, the knock-out alleles retained sufficient activity to be functional, or phenotypes produced by disruption of ZmbZIP1 are not detectable by the methods we used. In all cases, these results suggest more work must be done to determine the efficacy of ZmbZIP1 in regulating endosperm lysine levels. A molecular mechanism for increasing methionine deposition into maize endosperm was investigated with regards to two candidate genes: the 10kDa delta-zein (Dzs10), a v methionine-rich storage protein in endosperm, and cysteine synthase (Cys2), a key regulator in cysteine/methionine biosynthesis. mRNA expression levels and haplotypes were determined for each population, and were correlated to the average methionine content. At the mRNA level, Dzs10 was found to be differentially expressed in maize endosperm, while Cys2 is likely not differentially expressed. Further, a correlation of 0.4535 was found between Dzs10 mRNA and kernel methionine levels, suggesting part of the increase in kernel methionine deposition may be due
Load more

Recommended publications
  • First Insights Into the Mode of Action of a "Lachrymatory Factor Synthase"
    Phytochemistry 72 (2011) 1939–1946 Contents lists available at ScienceDirect Phytochemistry journal homepage: www.elsevier.com/locate/phytochem First insights into the mode of action of a ‘‘lachrymatory factor synthase’’ – Implications for the mechanism of lachrymator formation in Petiveria alliacea, Allium cepa and Nectaroscordum species ⇑ Quan He a, Roman Kubec b, Abhijit P. Jadhav a, Rabi A. Musah a, a Department of Chemistry, University at Albany, State University of New York, Albany, NY 12222, USA b Department of Applied Chemistry, University of South Bohemia, Branišovská 31, 370 05 Cˇeské Budeˇjovice, Czech Republic article info abstract Article history: A study of an enzyme that reacts with the sulfenic acid produced by the alliinase in Petiveria alliacea L. Received 16 December 2010 (Phytolaccaceae) to yield the P. alliacea lachrymator (phenylmethanethial S-oxide) showed the protein Received in revised form 11 July 2011 to be a dehydrogenase. It functions by abstracting hydride from sulfenic acids of appropriate structure Available online 15 August 2011 to form their corresponding sulfines. Successful hydride abstraction is dependent upon the presence of a benzyl group on the sulfur to stabilize the intermediate formed on abstraction of hydride. This dehy- Keywords: drogenase activity contrasts with that of the lachrymatory factor synthase (LFS) found in onion, which Petiveria alliacea catalyzes the rearrangement of 1-propenesulfenic acid to (Z)-propanethial S-oxide, the onion lachryma- Phytolaccaceae tor. Based on the type of reaction it catalyzes, the onion LFS should be classified as an isomerase and Lachrymatory factor synthase Sulfenic acid would be called a ‘‘sulfenic acid isomerase’’, whereas the P. alliacea LFS would be termed a ‘‘sulfenic acid Sulfenic acid dehydrogenase dehydrogenase’’.
    [Show full text]
  • The Biochemical and Physiological Genesis of Alliin in Garlic
    Medicinal and Aromatic Plant Science and Biotechnology ©2007 Global Science Books The Biochemical and Physiological Genesis of Alliin in Garlic M.G. Jones1 • H.A. Collin1 • A. Tregova1 • L. Trueman2 • L. Brown2 • R. Cosstick3 • J. Hughes1 • J. Milne1 • M.C. Wilkinson1 • A.B. Tomsett1 • B. Thomas2* 1 School of Biological Sciences, The Bioscience Building, Crown Street, The University of Liverpool, Liverpool, L69 7ZB, United Kingdom 2 Warwick HRI, University of Warwick, Wellesbourne, Warwick, CV35 9EF, United Kingdom 3 Department of Chemistry, Crown Street, The University of Liverpool, Liverpool, L69 7ZD, United Kingdom Corresponding author : * [email protected] ABSTRACT The health-giving properties of garlic are thought to be primarily derived from the presence and subsequent breakdown of the alk(en)ylcysteine sulphoxide (CSO), alliin and its subsequent breakdown to allicin. Two biosynthetic pathways have been proposed for CSOs, one proceeds from alkylation of glutathione through -glutamyl peptides to yield S-alkyl cysteine sulphoxides while the alternative is direct thioalkylation of serine followed by oxidation to the sulphoxide. Addition of allyl thiol to differentiating garlic tissue cultures resulted in the appearance of detectable levels of both S-allyl cysteine and alliin and also demonstrated that S-allyl-cysteine was oxidised stereospecifically to (+)-alliin by garlic tissue cultures, indicating the presence of a specific oxidase in the cells. Although these reports provide good evidence that S-allyl cysteine can be converted to alliin by garlic tissue cultures, it does not indicate whether "–glutamyl-S- allyl cysteine or S-allyl cysteine is the substrate for oxidation in vivo. Garlic contains several cysteine synthases and at least one has the capacity to synthesise alliin.
    [Show full text]
  • Alliinase from Ensifer Adhaerens and Its Use for Generation of Fungicidal
    Yutani et al. AMB Express 2011, 1:2 http://www.amb-express.com/content/1/1/2 ORIGINALARTICLE Open Access Alliinase from Ensifer adhaerens and Its Use for Generation of Fungicidal Activity Masahiro Yutani1, Hiroko Taniguchi1, Hasibagan Borjihan1, Akira Ogita1,2, Ken-ichi Fujita1, Toshio Tanaka1* Abstract AbacteriumEnsifer adhaerens FERM P-19486 with the ability of alliinase production was isolated from a soil sample. The enzyme was purified for characterization of its general properties and evaluation of its application in on-site production of allicin-dependent fungicidal activity. The bacterial alliinase was purified 300-fold from a cell-free extract, giving rise to a homogenous protein band on polyacrylamide gel electrophoresis. The bacterial alliinase (96 kDa) consisted of two identical subunits (48 kDa), and was most active at 60°C and at pH 8.0. The enzyme stoichiometrically converted (-)-alliin ((-)-S-allyl-L-cysteine sulfoxide) to form allicin, pyruvic acid, and ammonia more selectively than (+)-alliin, a naturally occurring substrate for plant alliinase ever known. The C-S lyase activity was also detected with this bacterial enzyme when S-alkyl-L-cysteine was used as a substrate, though such a lyase activity is absolutely absent in alliinase of plant origin. The enzyme generated a fungicidal activity against Saccharomyces cerevisiae in a time- and a dose-dependent fashion using alliin as a stable precursor. Alliinase of Ensifer adhaerens FERM P-19486 is the enzyme with a novel type of substrate specificity, and thus considered to be beneficial when used in combination with garlic enzyme with respect to absolute conversion of (±)-alliin to allicin.
    [Show full text]
  • In Situ Allicin Generation Using Targeted Alliinase Delivery
    Molecular Cancer Therapeutics 1295 Inhibition of tumor growth by a novel approach: In situ allicin generation using targeted alliinase delivery Talia Miron, Marina Mironchik, David Mirelman, odorless precursor alliin (S-allyl-L-cysteine sulfoxide). Meir Wilchek, and Aharon Rabinkov Alliin is converted to allicin, pyruvate, and ammonia by the pyridoxal 5V-phosphate (PLP)-dependent enzyme allii- Department of Biological Chemistry, The Weizmann Institute of Science, nase (alliin lyase; EC 4.4.1.4) (3), which is enclosed in Rehovot, Israel compartments within the garlic clove cells (Scheme 1). Crushing the clove exposes alliin to the enzyme, to initiate the following reaction: Abstract Allicin (diallyl thiosulfinate), a highly active component in extracts of freshly crushed garlic, is the interaction product of non-protein amino acid alliin (S-allyl-L-cysteine sulfoxide) with the enzyme alliinase (alliin lyase; EC Allicin reacts rapidly with free thiol groups and 4.4.1.4). Allicin was shown to be toxic in various penetrates biological membranes with ease (4, 5). It mammalian cells in a dose-dependent manner in vitro. therefore disappears from the circulation within a few We made use of this cytotoxicity to develop a novel minutes after injection (2, 4–6). This explains why the approach to cancer treatment, based on site-directed versatile and valuable activities of allicin, including its generation of allicin. Alliinase from garlic was chemically potent antibiotic and cytotoxic effects, were demonstrated conjugated to a mAb directed against a specific tumor thus far only in vitro (2, 7–9). We present here a new marker, ErbB2. After the mAb-alliinase conjugate was approach to anticancer therapy based on a localized, site- bound to target tumor cells, the substrate, alliin, was directed production of allicin.
    [Show full text]
  • Immobilization of Alliinase and Its Application: Flow- Injection Enzymatic Analysis for Alliin
    African Journal of Biotechnology Vol. 8 (7), pp. 1337-1342, 6 April, 2009 Available online at http://www.academicjournals.org/AJB ISSN 1684–5315 © 2009 Academic Journals Full Length Research Paper Immobilization of alliinase and its application: Flow- injection enzymatic analysis for alliin Jianqin Zhou School of Pharmaceutical Sciences, Medical College, Soochow University, Suzhou 215123, P.R., China. E-mail: [email protected]. Tel.: +86 512 65880025. Fax: +86 512 65880031. Accepted 26 February, 2009 Alliinase was immobilized on chitosan microspheres by means of glutaraldehyde, and a flow-injection enzymatic analytical system was developed for determination of alliin based on the immobilized alliinase and an ammonia gas electrode. The factors affecting the activity of the immobilized enzyme, such as glutaraldehyde concentration, cross-linking time and the amount of alliinase, were investigated. Results showed that the maximum of enzyme activity could be obtained at glutaraldehyde concentration of 4%, cross-linking time of 2 h and the amount of alliinase 20.2 u. The properties of the immobilized alliinase were also studied in detail. For the immobilized alliinase, the highest activity was allowed at pH of 7.0 and temperature at 35°C. Besides, the immobilized enzyme showed good thermal and pH stabilities. The flow-injection enzymatic analytical system based on the immobilized alliinase and an ammonia gas electrode provided linearity in the 1 × 10-5 to 1 × 10-3 mol/L alliin concentration range and exhibited good repeatability and operational stability. Key words: Alliinase, immobilization, enzyme properties, flow-injection analysis. INTRODUCTION Alliinase (alliin lyase EC 4.4.1.4) has been reported to and accurate method to measure the content of alliin.
    [Show full text]
  • An Introduction to Nutrition and Metabolism, 3Rd Edition
    INTRODUCTION TO NUTRITION AND METABOLISM INTRODUCTION TO NUTRITION AND METABOLISM third edition DAVID A BENDER Senior Lecturer in Biochemistry University College London First published 2002 by Taylor & Francis 11 New Fetter Lane, London EC4P 4EE Simultaneously published in the USA and Canada by Taylor & Francis Inc 29 West 35th Street, New York, NY 10001 Taylor & Francis is an imprint of the Taylor & Francis Group This edition published in the Taylor & Francis e-Library, 2004. © 2002 David A Bender All rights reserved. No part of this book may be reprinted or reproduced or utilised in any form or by any electronic, mechanical, or other means, now known or hereafter invented, including photocopying and recording, or in any information storage or retrieval system, without permission in writing from the publishers. British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library Library of Congress Cataloging in Publication Data Bender, David A. Introduction to nutrition and metabolism/David A. Bender.–3rd ed. p. cm. Includes bibliographical references and index. 1. Nutrition. 2. Metabolism. I. Title. QP141 .B38 2002 612.3′9–dc21 2001052290 ISBN 0-203-36154-7 Master e-book ISBN ISBN 0-203-37411-8 (Adobe eReader Format) ISBN 0–415–25798–0 (hbk) ISBN 0–415–25799–9 (pbk) Contents Preface viii Additional resources x chapter 1 Why eat? 1 1.1 The need for energy 2 1.2 Metabolic fuels 4 1.3 Hunger and appetite 6 chapter 2Enzymes and metabolic pathways 15 2.1 Chemical reactions: breaking and
    [Show full text]
  • Synthesis of Cysteine Sulfoxides and Related Compounds Occurring in Wild Onions
    Synthesis of cysteine sulfoxides and related compounds occurring in wild onions Dissertation zur Erlangung des Doktorgrades der Naturwissenschaften (Dr. rer. nat.) dem Fachbereich Pharmazie der Philipps-Universität Marburg vorgelegt von Mohammad Sadegh Feizabad aus Teheran / Iran Marburg/Lahn, 2019 i Erstgutachter: Prof. Dr. Michael Keusgen Zweitgutachter: Prof. Dr. Frank Runkel Tag der Einreichung Promotion: 24.04.2019 Tag der mündlichen Promotion: 24.06.2019 ii Dedicated to my beloved parents and wife for their precious supports and gentle, who have inspired me and been the driving force throughout my life. iii Foreword The majority of the genus Allium species are known for their medicinal applications: for example, A. stipitatum shows antibiotic effects against Mycobacterium tuberculosis and some other Allium species exhibit antistaphylococcal effects. Furthermore, recent studies have provided evidence of various antifungal, antidiabetic, and anticancer effects of some Allium species. Allium is also well known in traditional medicine for its ability to cure various ailments such as wounds or acute and chronic bronchitis; additionally, alliums can be used as expectorants due to the presence of cysteine sulfoxide and its derivatives. Cysteine sulfoxides, which are some of the basic secondary compounds in Allium, have been addressed in various studies. Alliin, propiin, methin, marasmin, and thiosulfinate, all of which are alliinase substrates, are of particular interest because of their pharmaceutical effects. The enzymatic reaction that occurs during the formation of disulfides or thiosufinates results in various compounds that differ chemically, physically, and pharmaceutically.The cysteine sulfoxide recently investigated in A. giganteum, A. rarolininanum, A. rosenorum, and A. macleani species is the S-(pyrrolyl)cysteine S-oxide.
    [Show full text]
  • The Health Benefits of Fruits and Vegetables
    The Health Benefits of Fruits and Vegetables • Mercedes Del Río Celestino and Rafael Villa Font The Health Benefits of Fruits and Vegetables Edited by Mercedes Del Río Celestino and Rafael Font Villa Printed Edition of the Special Issue Published in Foods www.mdpi.com/journal/foods The Health Benefits of Fruits and Vegetables The Health Benefits of Fruits and Vegetables Special Issue Editors Mercedes Del R´ıoCelestino Rafael Font Villa MDPI • Basel • Beijing • Wuhan • Barcelona • Belgrade • Manchester • Tokyo • Cluj • Tianjin Special Issue Editors Mercedes Del R´ıo Celestino Rafael Font Villa Agri-food Laboratory of Córdoba Agri-food Laboratory of Córdoba CAGPDS, Junta de Andalucía CAGPDS, Junta de Andalucía Córdoba, Spain Córdoba, Spain Editorial Office MDPI St. Alban-Anlage 66 4052 Basel, Switzerland This is a reprint of articles from the Special Issue published online in the open access journal Foods (ISSN 2304-8158) (available at: https://www.mdpi.com/journal/foods/special issues/Fruits phytochemicals Epidemiological). For citation purposes, cite each article independently as indicated on the article page online and as indicated below: LastName, A.A.; LastName, B.B.; LastName, C.C. Article Title. Journal Name Year, Article Number, Page Range. ISBN 978-3-03928-829-8 (Hbk) ISBN 978-3-03928-830-4 (PDF) Cover image courtesy of Mercedes del R´ıo Celestino. c 2020 by the authors. Articles in this book are Open Access and distributed under the Creative Commons Attribution (CC BY) license, which allows users to download, copy and build upon published articles, as long as the author and publisher are properly credited, which ensures maximum dissemination and a wider impact of our publications.
    [Show full text]
  • Medicinal Chemistry/Analytics, Natural Compounds, Biopharmaceutics As Well As Many Aspects of Pharmaceuti- Cal Technology and Drug Delivery
    Annual Meeting of the – DPhG Annual Meeting 2014 Annual Meeting of the German German Pharmaceutical Society – DPhG Pharmaceutical Society – DPhG Frankfurt/Main September 24 – 26, 2014 Trends and Perspectives in at Goethe University Pharmaceutical Sciences www.2014.dphg.de Conference Book Conference Book Conference Frankfurt/Main, September 24 – 26, 2014 at Goethe University ISBN 978-3-9816225-1-5 www.2014.dphg.de Annual Meeting of the German Pharmaceutical Society DPhG Trends and Perspectives in Pharmaceutical Sciences Conference Book Frankfurt/Main, September 24 26, 2014 at Goethe University www.2014.dphg.de Sponsors of the DPhG Annual Meeting 2014 MEDIEN FÜR DIE APOTHEKE Institutional Sponsors Förderer der DPhG-Jahrestagung 2014 CONFERENCE COMMITTEES Scientific Committee Prof. Dr. Thomas Efferth Prof. Dr. Christoph Friedrich Prof. Dr. Peter Gmeiner Prof. Dr. Ulrike Holzgrabe Prof. Dr. Ulrich Jaehde Prof. Dr. Jochen Klein Prof. Dr. Heyo Kroemer Prof. Dr. Peter Langguth Prof. Dr. Stefan Laufer Prof. Dr. Kristina Friedland Prof. Dr. Andreas Link Prof. Dr. Irmgard Merfort Prof. Dr. Klaus Mohr Dr. Olaf Queckenberg Prof. Dr. Peter Ruth Prof. Dr. Andrea Sinz Prof. Dr. Angelika Vollmar Prof. Dr. Hermann Wätzig Prof. Dr. Werner Weitschies Prof. Dr. Gerhard Winter Organisation Committee Seniorprof. Dr. Theodor Dingermann Prof. Dr. Jennifer Dressman PD. Dr. Gunter Eckert Prof. Dr. Robert Fürst Dr. Ann-Kathrin Häfner Dr. Bettina Hofmann Prof. Dr. Michael Karas PD. Dr. Thorsten Maier Prof. Dr. Rolf Marschalek Jun.-Prof. Dr. Eugen Proschak Dr. Bernd Sorg Dr. Michael Stein Dr. Mario Wurglics DPhG Annual Meeting 2014 3 ADDRESS OF WELCOME Dear colleagues, as President of the German Pharmaceutical Society (DPhG) and congress chair- man it is a pleasure for me to welcome you at Frankfurt to attend our Annual place for such a meeting which is part of the GU100 celebrations on the occa- sion of the 100th birthday of Goethe University.
    [Show full text]
  • Onion Cells After High Pressure and Thermal Processing
    Onion Cells After High Pressure and Thermal Processing: Comparison of Membrane Integrity Changes Using Different Analytical Methods and Impact on Tissue Texture Maria E. Gonzalez, Gordon E. Anthon, and Diane M. Barrett Abstract: Two different analytical methods were evaluated for their capacity to provide quantitative information on E: Food Engineering & onion cell membrane permeability and integrity after high pressure and thermal processing and to study the impact of Physical Properties these processing treatments on cell compartmentalization and texture quality. To determine changes in cell membrane permeability and/or integrity the methodologies utilized were: (1) measurement of a biochemical product, pyruvate, formed as a result of membrane permeabilization followed by enzymatic activity and (2) leakage of electrolytes into solution. These results were compared to previously determined methods that quantified cell viability and 1H-NMR T2 of onions. These methods allowed for the monitoring of changes in the plasma and tonoplast membranes after high pressure or thermal processing. High pressure treatments consisted of 5 min holding times at 50, 100, 200, 300, or 600 MPa. Thermal treatments consisted of 30 min water bath exposure to 40, 50, 60, 70, or 90 ◦C. There was strong agreement between the methods in the determination of the ranges of high pressure and temperature that induce changes in the integrity of the plasma and tonoplast membranes. Membrane rupture could clearly be identified at 300 MPa and above in high pressure treatments and at 60 ◦C and above in the thermal treatments. Membrane destabilization effects could already be visualized following the 200 MPa and 50 ◦C treatments.
    [Show full text]
  • A Comparison of the Antibacterial and Antifungal Activities of Thiosulfinate
    www.nature.com/scientificreports OPEN A Comparison of the Antibacterial and Antifungal Activities of Thiosulfnate Analogues of Allicin Received: 18 December 2017 Roman Leontiev1,2, Nils Hohaus1, Claus Jacob2, Martin C. H. Gruhlke1 & Alan J. Slusarenko1 Accepted: 16 April 2018 Allicin (diallylthiosulfnate) is a defence molecule from garlic (Allium sativum L.) with broad Published: xx xx xxxx antimicrobial activities in the low µM range against Gram-positive and -negative bacteria, including antibiotic resistant strains, and fungi. Allicin reacts with thiol groups and can inactivate essential enzymes. However, allicin is unstable at room temperature and antimicrobial activity is lost within minutes upon heating to >80 °C. Allicin’s antimicrobial activity is due to the thiosulfnate group, so we synthesized a series of allicin analogues and tested their antimicrobial properties and thermal stability. Dimethyl-, diethyl-, diallyl-, dipropyl- and dibenzyl-thiosulfnates were synthesized and tested in vitro against bacteria and the model fungus Saccharomyces cerevisiae, human and plant cells in culture and Arabidopsis root growth. The more volatile compounds showed signifcant antimicrobial properties via the gas phase. A chemogenetic screen with selected yeast mutants showed that the mode of action of the analogues was similar to that of allicin and that the glutathione pool and glutathione metabolism were of central importance for resistance against them. Thiosulfnates difered in their efectivity against specifc organisms and some were thermally more stable than allicin. These analogues could be suitable for applications in medicine and agriculture either singly or in combination with other antimicrobials. Garlic has been used since ancient times for its health benefcial properties and modern research has provided a scientifc basis for this practice1–3.
    [Show full text]
  • Enzyme-Catalyzed Transformations of Sulfur-Containing Flavor Precursors
    Lehrstuhl für Allgemeine Lebensmitteltechnologie der Technischen Universität München Enzyme-catalyzed transformations of sulfur-containing flavor precursors Hidehiko WAKABAYASHI Vollständiger Abdruck der von der Fakultät Wissenschaftszentrum Weihenstephan für Ernährung, Landnutzung und Umwelt der Technischen Universität München zur Erlangung des akademischen Grades eines Doktors der Naturwissenschaften (Dr. rer. nat.) genehmigten Dissertation Vorsitzender: Univ.-Prof. Dr. W. Schwab Prüfer der Dissertation: 1. Univ.-Prof. Dr. K.-H. Engel 2. Univ.-Prof. Dr. P. Schieberle Die Dissertation wurde am 22.03.2004 bei der Technischen Universität München eingereicht und durch die Fakultät Wissenschaftszentrum Weihenstephan für Ernährung, Landnutzung und Umwelt am 27.04.2004 angenommen. Danksagung Herrn Prof. Dr. K.-H. Engel danke ich herzlich für die Überlassung des Themas, die hervorragende Betreuung, die wertvollen Ratschläge und Diskussionen, sowie für das mir entgegengebrachte Vertrauen. Besonders danke ich Herrn Dr. W. Eisenreich vom Institut für Organische Chemie und Biochemie der Technischen Universität München für die Aufnahme der NMR-Spektren und die Unterstützung bei der Interpretation. Mein Dank gilt weiter Frau M. Hadek, Herrn Dr. M. A. Ehrmann und Herrn Prof. Dr. R. F. Vogel vom Lehrstuhl für Technische Mikrobiologie der Technischen Universität München für die Kultivierung von E. limosum. Mein besonderer Dank gilt Frau M. Dregus, Frau A. Schellenberg, Herrn Dr. L. Ziegler, Herrn Dr. B. Meier und Herrn Dr. L. Adam für die hervorragende Betreuung und die Hilfsbereitschaft sowie das angenehme Arbeitsklima. Herrn Dr. H.-G. Schmarr danke ich für die technische Unterstützung bei den gaschromatographischen Untersuchungen. Allen Mitarbeitern des Lehrstuhls für Allgemeine Lebensmitteltechnologie insbesondere Frau T. Feuerbach, Herrn A. Miller, Herrn T. Müller, Herrn M.
    [Show full text]