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Lim JY, Choi YJ, Choi JY, Yang JH, Chung YB, Park SH, Min SG, Lee MA. Microbial Dynamics and Metabolite Profiles in Different Types of Salted Seafood ( Jeotgal) During Fermentation. ACS OMEGA 2024; 9:35798-35808. [PMID: 39184488 PMCID: PMC11339811 DOI: 10.1021/acsomega.4c04410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2024] [Revised: 07/22/2024] [Accepted: 08/02/2024] [Indexed: 08/27/2024]
Abstract
Salted and fermented seafood (jeotgal) is known for its long shelf life and unique flavor. Despite the existence of various types of salted seafood, the factors influencing this quality have yet to be identified. These factors are essential for improving the quality of salted seafood, optimizing the fermentation process, and advancing the industrialization of fermented foods. Therefore, in this study, we explored microbial dynamics and changes in quality characteristics in three salted seafood items - salted anchovies (MJ), salted cutlass offal (GJ), and salted croakers (HJ), over a 24-month fermentation period. Distinct microbial community profiles, dominated by Tetragenococcus halophilus, Halanaerobium fermentans, and Chromohalobacter canadensis in MJ, GJ, and HJ, respectively, affect the metabolic pathways and the corresponding flavor profiles. The pH of all samples ranged from 5.7-6.0. The titratable acidity was highest in MJ at 1.4% and lowest in HJ at approximately 0.7%. Salinity was below 25% in all samples but slightly lower in MJ. Significant differences were observed in the amino acid, nucleotide, and overall metabolite profiles. MJ exhibited the highest amino acid and nitrogen-related factor levels, such as glutamic acid and hypoxanthine, enhancing flavor complexity. Correlation analysis revealed significant associations among the types, metabolites, and microbial communities. Microbial survival mechanisms in high-salt environments result in the production of unique metabolites, including umami and aroma components as well as precursors of biogenic amines, which can affect the overall quality of the final product. These differences were primarily influenced by the fish type rather than the fermentation time. Our findings provide foundational insights for enhancing fermentation strategies, improving product consistency, and advancing the industrial application of microbial management in seafood fermentation. This study not only fills a significant gap in the current understanding of fermented seafood but also outlines practical approaches for industry applications for the optimization of product quality.
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Affiliation(s)
- Ju-Young Lim
- Practical
Technology Research Group, World Institute
of Kimchi, Kimchiro 86, Gwangju 61755, Republic of Korea
- Department
of Food and Nutrition, Kyung Hee University, Seoul 02447, Republic of Korea
| | - Yun-Jeong Choi
- Practical
Technology Research Group, World Institute
of Kimchi, Kimchiro 86, Gwangju 61755, Republic of Korea
| | - Ji-Young Choi
- Practical
Technology Research Group, World Institute
of Kimchi, Kimchiro 86, Gwangju 61755, Republic of Korea
| | - Ji-Hee Yang
- Practical
Technology Research Group, World Institute
of Kimchi, Kimchiro 86, Gwangju 61755, Republic of Korea
| | - Young Bae Chung
- Practical
Technology Research Group, World Institute
of Kimchi, Kimchiro 86, Gwangju 61755, Republic of Korea
| | - Sung-Hee Park
- Practical
Technology Research Group, World Institute
of Kimchi, Kimchiro 86, Gwangju 61755, Republic of Korea
| | - Sung Gi Min
- Practical
Technology Research Group, World Institute
of Kimchi, Kimchiro 86, Gwangju 61755, Republic of Korea
| | - Mi-Ai Lee
- Practical
Technology Research Group, World Institute
of Kimchi, Kimchiro 86, Gwangju 61755, Republic of Korea
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Lebrazi S, Fadil M, Chraibi M, Fikri-Benbrahim K. Phenotypic, molecular, and symbiotic characterization of the rhizobial symbionts isolated from Acacia saligna grown in different regions in Morocco: a multivariate approach. World J Microbiol Biotechnol 2023; 39:343. [PMID: 37843647 DOI: 10.1007/s11274-023-03775-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 09/20/2023] [Indexed: 10/17/2023]
Abstract
The introduced species Acacia saligna is a very promiscuous host as it can be efficiently nodulated with a wide range diversity of rhizobia taxa, including both fast and slow-growing strains. Fourteen nitrogen (N)-fixing bacteria were isolated from root nodules of wild Acacia saligna growing in distinct geographic locations in Morocco and were examined for their symbiotic efficiency and phenotypic properties. Multivariate tools, such as principal component analysis (PCA) and hierarchical clustering analysis (HCA), were used to study the correlation between phenotypic and symbiotic variables and discriminate and describe the similarities between different isolated bacteria with respect to all the phenotypic and symbiotic variables. Phenotypic characterization showed a variable response to extreme temperature, salinity and soil pH. At the plant level, the nodulation, nitrogen fixation, and the shoot and root dry weights were considered. The obtained results show that some of the tested isolates exhibit remarkable tolerances to the studied abiotic stresses while showing significant N2 fixation, indicating their usefulness as effective candidates for the inoculation of acacia trees. The PCA also allowed showing the isolates groups that present a similarity with evaluated phenotypic and symbiotic parameters. The genotypic identification of N2-fixing bacteria, carried out by the 16S rDNA approach, showed a variable genetic diversity among the 14 identified isolates, and their belonging to three different genera, namely Agrobacterium, Phyllobacterium and Rhizobium.
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Affiliation(s)
- Sara Lebrazi
- Microbial Biotechnology and Bioactive Molecules Laboratory, Sciences and Technologies Faculty, Sidi Mohamed Ben Abdellah University, Fez, Morocco.
| | - Mouhcine Fadil
- Laboratory of Applied Organic Chemistry, Faculty of Sciences and Techniques, Sidi Mohamed Ben Abdellah University, Fez, Morocco
| | - Marwa Chraibi
- Microbial Biotechnology and Bioactive Molecules Laboratory, Sciences and Technologies Faculty, Sidi Mohamed Ben Abdellah University, Fez, Morocco
| | - Kawtar Fikri-Benbrahim
- Microbial Biotechnology and Bioactive Molecules Laboratory, Sciences and Technologies Faculty, Sidi Mohamed Ben Abdellah University, Fez, Morocco
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Jung H, Lee D, Lee S, Kong HJ, Park J, Seo YS. Comparative genomic analysis of Chryseobacterium species: deep insights into plant-growth-promoting and halotolerant capacities. Microb Genom 2023; 9:001108. [PMID: 37796250 PMCID: PMC10634447 DOI: 10.1099/mgen.0.001108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 09/17/2023] [Indexed: 10/06/2023] Open
Abstract
Members of the genus Chryseobacterium have attracted great interest as beneficial bacteria that can promote plant growth and biocontrol. Given the recent risks of climate change, it is important to develop tolerance strategies for efficient applications of plant-beneficial bacteria in saline environments. However, the genetic determinants of plant-growth-promoting and halotolerance effects in Chryseobacterium have not yet been investigated at the genomic level. Here, a comparative genomic analysis was conducted with seven Chryseobacterium species. Phylogenetic and phylogenomic analyses revealed niche-specific evolutionary distances between soil and freshwater Chryseobacterium species, consistent with differences in genomic statistics, indicating that the freshwater bacteria have smaller genome sizes and fewer genes than the soil bacteria. Phosphorus- and zinc-cycling genes (required for nutrient acquisition in plants) were universally present in all species, whereas nitrification and sulphite reduction genes (required for nitrogen- and sulphur-cycling, respectively) were distributed only in soil bacteria. A pan-genome containing 6842 gene clusters was constructed, which reflected the general features of the core, accessory and unique genomes. Halotolerant species with an accessory genome shared a Kdp potassium transporter and biosynthetic pathways for branched-chain amino acids and the carotenoid lycopene, which are associated with countermeasures against salt stress. Protein-protein interaction network analysis was used to define the genetic determinants of Chryseobacterium salivictor NBC122 that reduce salt damage in bacteria and plants. Sixteen hub genes comprised the aromatic compound degradation and Por secretion systems, which are required to cope with complex stresses associated with saline environments. Horizontal gene transfer and CRISPR-Cas analyses indicated that C. salivictor NBC122 underwent more evolutionary events when interacting with different environments. These findings provide deep insights into genomic adaptation to dynamic interactions between plant-growth-promoting Chryseobacterium and salt stress.
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Affiliation(s)
- Hyejung Jung
- Department of Integrated Biological Science, Pusan National University, Busan 46241, South Korea
- Biotechnology Research Division, National Institute of Fisheries Science, Busan 46083, South Korea
| | - Duyoung Lee
- Department of Integrated Biological Science, Pusan National University, Busan 46241, South Korea
| | - Seungchul Lee
- Department of Integrated Biological Science, Pusan National University, Busan 46241, South Korea
| | - Hee Jeong Kong
- Biotechnology Research Division, National Institute of Fisheries Science, Busan 46083, South Korea
| | - Jungwook Park
- Department of Integrated Biological Science, Pusan National University, Busan 46241, South Korea
- Biotechnology Research Division, National Institute of Fisheries Science, Busan 46083, South Korea
| | - Young-Su Seo
- Department of Integrated Biological Science, Pusan National University, Busan 46241, South Korea
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Hawkins JP, Oresnik IJ. The Rhizobium-Legume Symbiosis: Co-opting Successful Stress Management. FRONTIERS IN PLANT SCIENCE 2022; 12:796045. [PMID: 35046982 PMCID: PMC8761673 DOI: 10.3389/fpls.2021.796045] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 12/02/2021] [Indexed: 05/20/2023]
Abstract
The interaction of bacteria with plants can result in either a positive, negative, or neutral association. The rhizobium-legume interaction is a well-studied model system of a process that is considered a positive interaction. This process has evolved to require a complex signal exchange between the host and the symbiont. During this process, rhizobia are subject to several stresses, including low pH, oxidative stress, osmotic stress, as well as growth inhibiting plant peptides. A great deal of work has been carried out to characterize the bacterial response to these stresses. Many of the responses to stress are also observed to have key roles in symbiotic signaling. We propose that stress tolerance responses have been co-opted by the plant and bacterial partners to play a role in the complex signal exchange that occurs between rhizobia and legumes to establish functional symbiosis. This review will cover how rhizobia tolerate stresses, and how aspects of these tolerance mechanisms play a role in signal exchange between rhizobia and legumes.
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Affiliation(s)
| | - Ivan J. Oresnik
- Department of Microbiology, University of Manitoba, Winnipeg, MB, Canada
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5
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Comparative transcriptomics analysis of Zygosaccharomyces mellis under high-glucose stress. FOOD SCIENCE AND HUMAN WELLNESS 2021. [DOI: 10.1016/j.fshw.2020.05.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Viver T, Orellana LH, Díaz S, Urdiain M, Ramos‐Barbero MD, González‐Pastor JE, Oren A, Hatt JK, Amann R, Antón J, Konstantinidis KT, Rosselló‐Móra R. Predominance of deterministic microbial community dynamics in salterns exposed to different light intensities. Environ Microbiol 2019; 21:4300-4315. [DOI: 10.1111/1462-2920.14790] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 08/19/2019] [Accepted: 08/22/2019] [Indexed: 12/22/2022]
Affiliation(s)
- Tomeu Viver
- Marine Microbiology Group, Department of Animal and Microbial Biodiversity Mediterranean Institute for Advanced Studies (IMEDEA, CSIC‐UIB) Esporles Spain
| | - Luis H. Orellana
- School of Civil and Environmental Engineering Georgia Institute of Technology Atlanta GA USA
| | - Sara Díaz
- Marine Microbiology Group, Department of Animal and Microbial Biodiversity Mediterranean Institute for Advanced Studies (IMEDEA, CSIC‐UIB) Esporles Spain
| | - Mercedes Urdiain
- Marine Microbiology Group, Department of Animal and Microbial Biodiversity Mediterranean Institute for Advanced Studies (IMEDEA, CSIC‐UIB) Esporles Spain
| | | | - José E. González‐Pastor
- Laboratory of Molecular Adaptation, Department of Molecular Evolution, Centro de Astrobiología Consejo Superior de Investigaciones Científicas – Instituto Nacional de Técnica Aeroespacial Madrid Spain
| | - Aharon Oren
- Department of Plant and Environmental Sciences The Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus Jerusalem 9190401 Israel
| | - Janet K. Hatt
- School of Civil and Environmental Engineering Georgia Institute of Technology Atlanta GA USA
| | - Rudolf Amann
- Department of Molecular Ecology Max‐Planck‐Institut für Marine Mikrobiologie Bremen D‐28359 Germany
| | - Josefa Antón
- Department of Physiology, Genetics and Microbiology University of Alicante Alicante Spain
| | | | - Ramon Rosselló‐Móra
- Marine Microbiology Group, Department of Animal and Microbial Biodiversity Mediterranean Institute for Advanced Studies (IMEDEA, CSIC‐UIB) Esporles Spain
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Becerra-Rivera VA, Dunn MF. Polyamine biosynthesis and biological roles in rhizobia. FEMS Microbiol Lett 2019; 366:5476500. [DOI: 10.1093/femsle/fnz084] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 04/22/2019] [Indexed: 12/31/2022] Open
Abstract
ABSTRACTPolyamines are ubiquitous molecules containing two or more amino groups that fulfill varied and often essential physiological and regulatory roles in all organisms. In the symbiotic nitrogen-fixing bacteria known as rhizobia, putrescine and homospermidine are invariably produced while spermidine and norspermidine synthesis appears to be restricted to the alfalfa microsymbiont Sinorhizobium meliloti. Studies with rhizobial mutants deficient in the synthesis of one or more polyamines have shown that these compounds are important for growth, stress resistance, motility, exopolysaccharide production and biofilm formation. In this review, we describe these studies and examine how polyamines are synthesized and regulated in rhizobia.
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Affiliation(s)
- Victor A Becerra-Rivera
- Programa de Genómica Funcional de Procariotes, Centro de Ciencias Genómicas-Universidad Nacional Autónoma de México, Cuernavaca, Morelos, C.P. 62210, Mexico
| | - Michael F Dunn
- Programa de Genómica Funcional de Procariotes, Centro de Ciencias Genómicas-Universidad Nacional Autónoma de México, Cuernavaca, Morelos, C.P. 62210, Mexico
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Atieno M, Lesueur D. Opportunities for improved legume inoculants: enhanced stress tolerance of rhizobia and benefits to agroecosystems. Symbiosis 2018. [DOI: 10.1007/s13199-018-0585-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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9
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Hakobyan A, Liesack W, Glatter T. Crude-MS Strategy for in-Depth Proteome Analysis of the Methane-Oxidizing Methylocystis sp. strain SC2. J Proteome Res 2018; 17:3086-3103. [DOI: 10.1021/acs.jproteome.8b00216] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
| | - Werner Liesack
- Center for Synthetic Microbiology (SYNMIKRO), Philipps-Universität Marburg, Karl-von-Frisch-Str. 16, D-35043 Marburg, Germany
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Hassanov T, Karunker I, Steinberg N, Erez A, Kolodkin-Gal I. Novel antibiofilm chemotherapies target nitrogen from glutamate and glutamine. Sci Rep 2018; 8:7097. [PMID: 29740028 PMCID: PMC5940852 DOI: 10.1038/s41598-018-25401-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 04/19/2018] [Indexed: 01/06/2023] Open
Abstract
Bacteria in nature often reside in differentiated communities termed biofilms, which are an active interphase between uni-cellular and multicellular life states for bacteria. Here we demonstrate that the development of B. subtilis biofilms is dependent on the use of glutamine or glutamate as a nitrogen source. We show a differential metabolic requirement within the biofilm; while glutamine is necessary for the dividing cells at the edges, the inner cell mass utilizes lactic acid. Our results indicate that biofilm cells preserve a short-term memory of glutamate metabolism. Finally, we establish that drugs that target glutamine and glutamate utilization restrict biofilm development. Overall, our work reveals a spatial regulation of nitrogen and carbon metabolism within the biofilm, which contributes to the fitness of bacterial complex communities. This acquired metabolic division of labor within biofilm can serve as a target for novel anti-biofilm chemotherapies
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Affiliation(s)
- Tal Hassanov
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Iris Karunker
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Nitai Steinberg
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Ayelet Erez
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel
| | - Ilana Kolodkin-Gal
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel.
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11
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Benidire L, Lahrouni M, Daoui K, Fatemi ZEA, Gomez Carmona R, Göttfert M, Oufdou K. Phenotypic and genetic diversity of Moroccan rhizobia isolated from Vicia faba and study of genes that are likely to be involved in their osmotolerance. Syst Appl Microbiol 2018; 41:51-61. [DOI: 10.1016/j.syapm.2017.09.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 09/04/2017] [Accepted: 09/05/2017] [Indexed: 01/28/2023]
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12
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Ramadan T, Abd-Alla MH, Elenany AE, Alzohri M, Nafady IM. Differential Antioxidative Responses to Environmental Constraints in Shoots and Roots of Wild Legumes. GLOBAL JOURNAL OF BOTANICAL SCIENCE 2017; 5:63-73. [DOI: 10.12974/2311-858x.2017.05.02.4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
The current study aimed to explore the antioxidant system of five legumes inhabiting regions with different conditions. In these legumes, H2O2 generation and lipid peroxidation enhanced in roots of plants inhabiting the Mediterranean region (MR) and Sinai (S) where high soluble salts and low water content in the soil were estimated. High levels of phenols and ascorbic acid were detected in shoots of these plants compared with those inhabiting the Nile region (NR) or Oases (O), which characterized by low soluble salts and high water content. There were great variations between species in their responses to adverse conditions, and enhanced activities of antioxidant enzymes were recorded in plants inhabiting the more stressful habitats. Roots and shoots of legumes responded differentially to oxidative stresses regarding the induction of enhanced or suppressed activities of a definite antioxidative enzym. While CAT activity increased in shoots, GP activity greatly stimulated in roots of legumes at different habitats. The activity of APX decreased in roots but increased in shoots by the harsh conditions of habitate showing minimum and maximum activities in roots and shoots, respectively, in plants inhabiting S. The activity of CAT and APX increased in shoots by increasing the concentration of H2O2, while the over expression of GP gene in roots enhanced scavenging H2O2 to a level between 6% to 37% of its concentration in shoots. Genes expression of the antioxidant enzymes (CAT, GP and APX) more regulated, especially in shoots, by the environmental constraints than the differences between species.
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He G, Wu C, Huang J, Zhou R. Metabolic response of Tetragenococcus halophilus under salt stress. BIOTECHNOL BIOPROC E 2017. [DOI: 10.1007/s12257-017-0015-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Sévin DC, Stählin JN, Pollak GR, Kuehne A, Sauer U. Global Metabolic Responses to Salt Stress in Fifteen Species. PLoS One 2016; 11:e0148888. [PMID: 26848578 PMCID: PMC4743995 DOI: 10.1371/journal.pone.0148888] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 01/25/2016] [Indexed: 11/18/2022] Open
Abstract
Cells constantly adapt to unpredictably changing extracellular solute concentrations. A cornerstone of the cellular osmotic stress response is the metabolic supply of energy and building blocks to mount appropriate defenses. Yet, the extent to which osmotic stress impinges on the metabolic network remains largely unknown. Moreover, it is mostly unclear which, if any, of the metabolic responses to osmotic stress are conserved among diverse organisms or confined to particular groups of species. Here we investigate the global metabolic responses of twelve bacteria, two yeasts and two human cell lines exposed to sustained hyperosmotic salt stress by measuring semiquantitative levels of hundreds of cellular metabolites using nontargeted metabolomics. Beyond the accumulation of osmoprotectants, we observed significant changes of numerous metabolites in all species. Global metabolic responses were predominantly species-specific, yet individual metabolites were characteristically affected depending on species’ taxonomy, natural habitat, envelope structure or salt tolerance. Exploiting the breadth of our dataset, the correlation of individual metabolite response magnitudes across all species implicated lower glycolysis, tricarboxylic acid cycle, branched-chain amino acid metabolism and heme biosynthesis to be generally important for salt tolerance. Thus, our findings place the global metabolic salt stress response into a phylogenetic context and provide insights into the cellular phenotype associated with salt tolerance.
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Affiliation(s)
- Daniel C. Sévin
- Institute of Molecular Systems Biology, ETH Zürich, Zurich, Switzerland
- PhD Program on Systems Biology, Life Science Zurich, Zurich, Switzerland
- * E-mail: (US); (DCS)
| | | | - Georg R. Pollak
- Institute of Molecular Systems Biology, ETH Zürich, Zurich, Switzerland
| | - Andreas Kuehne
- Institute of Molecular Systems Biology, ETH Zürich, Zurich, Switzerland
- PhD Program on Systems Biology, Life Science Zurich, Zurich, Switzerland
| | - Uwe Sauer
- Institute of Molecular Systems Biology, ETH Zürich, Zurich, Switzerland
- * E-mail: (US); (DCS)
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Chaudhry V, Bhatia A, Bharti SK, Mishra SK, Chauhan PS, Mishra A, Sidhu OP, Nautiyal CS. Metabolite profiling reveals abiotic stress tolerance in Tn5 mutant of Pseudomonas putida. PLoS One 2015; 10:e0113487. [PMID: 25629312 PMCID: PMC4309533 DOI: 10.1371/journal.pone.0113487] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 10/15/2014] [Indexed: 11/27/2022] Open
Abstract
Pseudomonas is an efficient plant growth–promoting rhizobacteria (PGPR); however, intolerance to drought and high temperature limit its application in agriculture as a bioinoculant. Transposon 5 (Tn5) mutagenesis was used to generate a stress tolerant mutant from a PGPR Pseudomonas putida NBRI1108 isolated from chickpea rhizosphere. A mutant NBRI1108T, selected after screening of nearly 10,000 transconjugants, exhibited significant tolerance towards high temperature and drought. Southern hybridization analysis of EcoRI and XhoI restricted genomic DNA of NBRI1108T confirmed that it had a single Tn5 insertion. The metabolic changes in the polar and non-polar extracts of NBRI1108 and NBRI1108T were examined using 1H, 31P nuclear magnetic resonance (NMR) spectroscopy and gas chromatography-mass spectrometry (GC-MS). Thirty six chemically diverse metabolites consisting of amino acids, fatty acids and phospholipids were identified and quantified. Insertion of Tn5 influenced amino acid and phospholipid metabolism and resulted in significantly higher concentration of aspartic acid, glutamic acid, glycinebetaine, glycerophosphatidylcholine (GPC) and putrescine in NBRI1108T as compared to that in NBRI1108. The concentration of glutamic acid, glycinebetaine and GPC increased by 34%, 95% and 100%, respectively in the NBRI1108T as compared to that in NBRI1108. High concentration of glycerophosphatidylethanolamine (GPE) and undetected GPC in NBRI1108 indicates that biosynthesis of GPE may have taken place via the methylation pathway of phospholipid biosynthesis. However, high GPC and low GPE concentration in NBRI1108T suggest that methylation pathway and phosphatidylcholine synthase (PCS) pathway of phospholipid biosynthesis are being followed in the NBRI1108T. Application of multivariate principal component analysis (PCA) on the quantified metabolites revealed clear variations in NBRI1108 and NBRI1108T in polar and non-polar metabolites. Identification of abiotic stress tolerant metabolites from the NBRI1108T suggest that Tn5 mutagenesis enhanced tolerance towards high temperature and drought. Tolerance to drought was further confirmed in greenhouse experiments with maize as host plant, where NBRI1108T showed relatively high biomass under drought conditions.
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Affiliation(s)
- Vasvi Chaudhry
- Council of Scientific & Industrial Research-National Botanical Research Institute, Rana Pratap Marg, Lucknow, Uttar Pradesh, India
| | - Anil Bhatia
- Council of Scientific & Industrial Research-National Botanical Research Institute, Rana Pratap Marg, Lucknow, Uttar Pradesh, India
| | - Santosh Kumar Bharti
- Council of Scientific & Industrial Research-National Botanical Research Institute, Rana Pratap Marg, Lucknow, Uttar Pradesh, India
| | - Shashank Kumar Mishra
- Council of Scientific & Industrial Research-National Botanical Research Institute, Rana Pratap Marg, Lucknow, Uttar Pradesh, India
| | - Puneet Singh Chauhan
- Council of Scientific & Industrial Research-National Botanical Research Institute, Rana Pratap Marg, Lucknow, Uttar Pradesh, India
| | - Aradhana Mishra
- Council of Scientific & Industrial Research-National Botanical Research Institute, Rana Pratap Marg, Lucknow, Uttar Pradesh, India
| | - Om Prakash Sidhu
- Council of Scientific & Industrial Research-National Botanical Research Institute, Rana Pratap Marg, Lucknow, Uttar Pradesh, India
| | - Chandra Shekhar Nautiyal
- Council of Scientific & Industrial Research-National Botanical Research Institute, Rana Pratap Marg, Lucknow, Uttar Pradesh, India
- * E-mail:
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Characterization of NaCl tolerance in Desulfovibrio vulgaris Hildenborough through experimental evolution. ISME JOURNAL 2013; 7:1790-802. [PMID: 23575373 DOI: 10.1038/ismej.2013.60] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2012] [Revised: 03/01/2013] [Accepted: 03/09/2013] [Indexed: 11/08/2022]
Abstract
Desulfovibrio vulgaris Hildenborough strains with significantly increased tolerance to NaCl were obtained via experimental evolution. A NaCl-evolved strain, ES9-11, isolated from a population cultured for 1200 generations in medium amended with 100 mM NaCl, showed better tolerance to NaCl than a control strain, EC3-10, cultured for 1200 generations in parallel but without NaCl amendment in medium. To understand the NaCl adaptation mechanism in ES9-11, we analyzed the transcriptional, metabolite and phospholipid fatty acid (PLFA) profiles of strain ES9-11 with 0, 100- or 250 mM-added NaCl in medium compared with the ancestral strain and EC3-10 as controls. In all the culture conditions, increased expressions of genes involved in amino-acid synthesis and transport, energy production, cation efflux and decreased expression of flagellar assembly genes were detected in ES9-11. Consistently, increased abundances of organic solutes and decreased cell motility were observed in ES9-11. Glutamate appears to be the most important osmoprotectant in D. vulgaris under NaCl stress, whereas, other organic solutes such as glutamine, glycine and glycine betaine might contribute to NaCl tolerance under low NaCl concentration only. Unsaturation indices of PLFA significantly increased in ES9-11. Branched unsaturated PLFAs i17:1 ω9c, a17:1 ω9c and branched saturated i15:0 might have important roles in maintaining proper membrane fluidity under NaCl stress. Taken together, these data suggest that the accumulation of osmolytes, increased membrane fluidity, decreased cell motility and possibly an increased exclusion of Na(+) contribute to increased NaCl tolerance in NaCl-evolved D. vulgaris.
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Salt Tolerance in Astragalus cicer Microsymbionts: The Role of Glycine Betaine in Osmoprotection. Curr Microbiol 2013; 66:428-36. [DOI: 10.1007/s00284-012-0293-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Accepted: 12/07/2012] [Indexed: 11/26/2022]
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Faghire M, Mandri B, Oufdou K, Bargaz A, Ghoulam C, Ramírez-Bahena M, Velázquez E, Peix A. Identification at the species and symbiovar levels of strains nodulating Phaseolus vulgaris in saline soils of the Marrakech region (Morocco) and analysis of the otsA gene putatively involved in osmotolerance. Syst Appl Microbiol 2012; 35:156-64. [DOI: 10.1016/j.syapm.2012.02.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Revised: 02/03/2012] [Accepted: 02/04/2012] [Indexed: 11/29/2022]
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Brique A, Devassine J, Pilard S, Cailleu D, Gosselin I. Osmoregulated trehalose-derived oligosaccharides inSinorhizobium meliloti. FEBS Lett 2010; 584:3661-6. [DOI: 10.1016/j.febslet.2010.07.047] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Revised: 07/21/2010] [Accepted: 07/26/2010] [Indexed: 11/29/2022]
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Fernandez-Aunión C, Hamouda TB, Iglesias-Guerra F, Argandoña M, Reina-Bueno M, Nieto JJ, Aouani ME, Vargas C. Biosynthesis of compatible solutes in rhizobial strains isolated from Phaseolus vulgaris nodules in Tunisian fields. BMC Microbiol 2010; 10:192. [PMID: 20633304 PMCID: PMC2918589 DOI: 10.1186/1471-2180-10-192] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2010] [Accepted: 07/16/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Associated with appropriate crop and soil management, inoculation of legumes with microbial biofertilizers can improve food legume yield and soil fertility and reduce pollution by inorganic fertilizers. Rhizospheric bacteria are subjected to osmotic stress imposed by drought and/or NaCl, two abiotic constraints frequently found in semi-arid lands. Osmostress response in bacteria involves the accumulation of small organic compounds called compatible solutes. Whereas most studies on rhizobial osmoadaptation have focussed on the model species Sinorhizobium meliloti, little is known on the osmoadaptive mechanisms used by native rhizobia, which are good sources of inoculants. In this work, we investigated the synthesis and accumulations of compatible solutes by four rhizobial strains isolated from root nodules of Phaseolus vulgaris in Tunisia, as well as by the reference strain Rhizobium tropici CIAT 899T. RESULTS The most NaCl-tolerant strain was A. tumefaciens 10c2, followed (in decreasing order) by R. tropici CIAT 899, R. leguminosarum bv. phaseoli 31c3, R. etli 12a3 and R. gallicum bv. phaseoli 8a3. 13C- and 1H-NMR analyses showed that all Rhizobium strains synthesized trehalose whereas A. tumefaciens 10c2 synthesized mannosucrose. Glutamate synthesis was also observed in R. tropici CIAT 899, R. leguminosarum bv. phaseoli 31c3 and A. tumefaciens 10c2. When added as a carbon source, mannitol was also accumulated by all strains. Accumulation of trehalose in R. tropici CIAT 899 and of mannosucrose in A. tumefaciens 10c2 was osmoregulated, suggesting their involvement in osmotolerance. The phylogenetic analysis of the otsA gene, encoding the trehalose-6-phosphate synthase, suggested the existence of lateral transfer events. In vivo 13C labeling experiments together with genomic analysis led us to propose the uptake and conversion pathways of different carbon sources into trehalose. Collaterally, the beta-1,2-cyclic glucan from R. tropici CIAT 899 was co-extracted with the cytoplasmic compatible solutes and its chemical structure was determined. CONCLUSIONS The soil bacteria analyzed in this work accumulated mainly disaccharides in response to NaCl stress. We could not find a direct correlation between the trehalose content of the rhizobial strains and their osmotolerance, suggesting that additional osmoadaptive mechanism should be operating in the most NaCl-tolerant strain R. tropici CIAT 899.
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Talibart R, Jebbar M, Gouffi K, Pichereau V, Gouesbet G, Blanco C, Bernard T, Pocard J. Transient Accumulation of Glycine Betaine and Dynamics of Endogenous Osmolytes in Salt-Stressed Cultures of Sinorhizobium meliloti. Appl Environ Microbiol 2010; 63:4657-63. [PMID: 16535748 PMCID: PMC1389304 DOI: 10.1128/aem.63.12.4657-4663.1997] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The fate of exogenously supplied glycine betaine and the dynamics of endogenous osmolytes were investigated throughout the growth cycle of salt-stressed cultures of strains of Sinorhizobium meliloti which differ in their ability to use glycine betaine as a growth substrate, but not as an osmoprotectant. We present (sup13)C nuclear magnetic resonance spectral and radiotracer evidence which demonstrates that glycine betaine is only transiently accumulated as a cytoplasmic osmolyte in young cultures of wild-type strains 102F34 and RCR2011. Specifically, these strains accumulate glycine betaine as a preferred osmolyte which virtually prevents the accumulation of endogenous osmolytes during the lag and early exponential phases of growth. Then, betaine levels in stressed cells decrease abruptly during the second half of the exponential phase. At this stage, the levels of glutamate and the dipeptide N-acetylglutaminylglutamine amide increase sharply so that the two endogenous solutes supplant glycine betaine in the ageing culture, in which it becomes a minor osmolyte because it is progressively catabolized. Ultimately, glycine betaine disappears when stressed cells reach the stationary phase. At this stage, wild-type strains of S. meliloti also accumulate the disaccharide trehalose as a third major endogenous osmolyte. By contrast, glycine betaine is always the dominant osmolyte and strongly suppresses the buildup of endogenous osmolytes at all stages of the growth cycle of a mutant strain, S. meliloti GMI766, which does not catabolize this exogenous osmoprotectant under any growth conditions.
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Elboutahiri N, Thami-Alami I, Udupa SM. Phenotypic and genetic diversity in Sinorhizobium meliloti and S. medicae from drought and salt affected regions of Morocco. BMC Microbiol 2010; 10:15. [PMID: 20089174 PMCID: PMC2823721 DOI: 10.1186/1471-2180-10-15] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2009] [Accepted: 01/20/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Sinorhizobium meliloti and S. medicae are symbiotic nitrogen fixing bacteria in root nodules of forage legume alfalfa (Medicago sativa L.). In Morocco, alfalfa is usually grown in marginal soils of arid and semi-arid regions frequently affected by drought, extremes of temperature and soil pH, soil salinity and heavy metals, which affect biological nitrogen fixing ability of rhizobia and productivity of the host. This study examines phenotypic diversity for tolerance to the above stresses and genotypic diversity at Repetitive Extragenic Pallindromic DNA regions of Sinorhizobium nodulating alfalfa, sampled from marginal soils of arid and semi-arid regions of Morocco. RESULTS RsaI digestion of PCR amplified 16S rDNA of the 157 sampled isolates, assigned 136 isolates as S. meliloti and the rest as S. medicae. Further phenotyping of these alfalfa rhizobia for tolerance to the environmental stresses revealed a large degree of variation: 55.41%, 82.16%, 57.96% and 3.18% of the total isolates were tolerant to NaCl (>513 mM), water stress (-1.5 MPa), high temperature (40 degrees C) and low pH (3.5), respectively. Sixty-seven isolates of S. meliloti and thirteen isolates of S. medicae that were tolerant to salinity were also tolerant to water stress. Most of the isolates of the two species showed tolerance to heavy metals (Cd, Mn and Zn) and antibiotics (chloramphenicol, spectinomycin, streptomycin and tetracycline). The phenotypic clusters observed by the cluster analysis clearly showed adaptations of the S. meliloti and S. medicae strains to the multiple stresses. Genotyping with rep-PCR revealed higher genetic diversity within these phenotypic clusters and classified all the 157 isolates into 148 genotypes. No relationship between genotypic profiles and the phenotypes was observed. The Analysis of Molecular Variance revealed that largest proportion of significant (P < 0.01) genetic variation was distributed within regions (89%) than among regions (11%). CONCLUSION High degree of phenotypic and genotypic diversity is present in S. meliloti and S. medicae populations from marginal soils affected by salt and drought, in arid and semi-arid regions of Morocco. Some of the tolerant strains have a potential for exploitation in salt and drought affected areas for biological nitrogen fixation in alfalfa.
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Affiliation(s)
- Nadia Elboutahiri
- Institut National de la Recherche Agronomique (INRA), Centre Régional de la Recherche Agronomique de Rabat, B,P, 415, Rabat, Morocco
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Global transcriptional, physiological, and metabolite analyses of the responses of Desulfovibrio vulgaris hildenborough to salt adaptation. Appl Environ Microbiol 2009; 76:1574-86. [PMID: 20038696 DOI: 10.1128/aem.02141-09] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The response of Desulfovibrio vulgaris Hildenborough to salt adaptation (long-term NaCl exposure) was examined by performing physiological, global transcriptional, and metabolite analyses. Salt adaptation was reflected by increased expression of genes involved in amino acid biosynthesis and transport, electron transfer, hydrogen oxidation, and general stress responses (e.g., heat shock proteins, phage shock proteins, and oxidative stress response proteins). The expression of genes involved in carbon metabolism, cell growth, and phage structures was decreased. Transcriptome profiles of D. vulgaris responses to salt adaptation were compared with transcriptome profiles of D. vulgaris responses to salt shock (short-term NaCl exposure). Metabolite assays showed that glutamate and alanine accumulated under salt adaptation conditions, suggesting that these amino acids may be used as osmoprotectants in D. vulgaris. Addition of amino acids (glutamate, alanine, and tryptophan) or yeast extract to the growth medium relieved salt-related growth inhibition. A conceptual model that links the observed results to currently available knowledge is proposed to increase our understanding of the mechanisms of D. vulgaris adaptation to elevated NaCl levels.
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Martínez-Salazar JM, Sandoval-Calderón M, Guo X, Castillo-Ramírez S, Reyes A, Loza MG, Rivera J, Alvarado-Affantranger X, Sánchez F, González V, Dávila G, Ramírez-Romero MA. The Rhizobium etli RpoH1 and RpoH2 sigma factors are involved in different stress responses. MICROBIOLOGY-SGM 2009; 155:386-397. [PMID: 19202087 DOI: 10.1099/mic.0.021428-0] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The physiological role and transcriptional expression of Rhizobium etli sigma factors rpoH1 and rpoH2 are reported in this work. Both rpoH1 and rpoH2 were able to complement the temperature-sensitive phenotype of an Escherichia coli rpoH mutant. The R. etli rpoH1 mutant was sensitive to heat shock, sodium hypochlorite and hydrogen peroxide, whereas the rpoH2 mutant was sensitive to NaCl and sucrose. The rpoH2 rpoH1 double mutant had increased sensitivity to heat shock and oxidative stress when compared with the rpoH1 single mutant. This suggests that in R. etli, RpoH1 is the main heat-shock sigma factor, but a more complete protective response could be achieved with the participation of RpoH2. Conversely, RpoH2 is involved in osmotic tolerance. In symbiosis with bean plants, the R. etli rpoH1 and rpoH2 rpoH1 mutants still elicited nodule formation, but exhibited reduced nitrogenase activity and bacterial viability in early and late symbiosis compared with nodules produced by rpoH2 mutants and wild-type strains. In addition, nodules formed by R. etli rpoH1 and rpoH2 rpoH1 mutants showed premature senescence. It was also determined that fixNf and fixKf expression was affected in rpoH1 mutants. Both rpoH genes were induced under microaerobic conditions and in the stationary growth phase, but not in response to heat shock. Analysis of the upstream region of rpoH1 revealed a sigma70 and a probable sigmaE promoter, whereas in rpoH2, one probable sigmaE-dependent promoter was detected. In conclusion, the two RpoH proteins operate under different stress conditions, RpoH1 in heat-shock and oxidative responses, and RpoH2 in osmotic tolerance.
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Affiliation(s)
- Jaime M Martínez-Salazar
- Programa de Ingeniería Genómica, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apartado Postal 565-A, CP 62210 Cuernavaca, Morelos, México
| | - Mario Sandoval-Calderón
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apartado Postal 565-A, CP 62210 Cuernavaca, Morelos, México
| | - Xianwu Guo
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apartado Postal 565-A, CP 62210 Cuernavaca, Morelos, México
| | - Santiago Castillo-Ramírez
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apartado Postal 565-A, CP 62210 Cuernavaca, Morelos, México
| | - Alma Reyes
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apartado Postal 565-A, CP 62210 Cuernavaca, Morelos, México
| | - Maria G Loza
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apartado Postal 565-A, CP 62210 Cuernavaca, Morelos, México
| | - Javier Rivera
- Programa de Ingeniería Genómica, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apartado Postal 565-A, CP 62210 Cuernavaca, Morelos, México
| | - Xochitl Alvarado-Affantranger
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apartado Postal 510-3, CP 62271 Cuernavaca, Morelos, México
| | - Federico Sánchez
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apartado Postal 510-3, CP 62271 Cuernavaca, Morelos, México
| | - Víctor González
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apartado Postal 565-A, CP 62210 Cuernavaca, Morelos, México
| | - Guillermo Dávila
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apartado Postal 565-A, CP 62210 Cuernavaca, Morelos, México
| | - Miguel A Ramírez-Romero
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apartado Postal 565-A, CP 62210 Cuernavaca, Morelos, México
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Vriezen JAC, de Bruijn FJ, Nüsslein K. Responses of rhizobia to desiccation in relation to osmotic stress, oxygen, and temperature. Appl Environ Microbiol 2007; 73:3451-9. [PMID: 17400779 PMCID: PMC1932662 DOI: 10.1128/aem.02991-06] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Jan A C Vriezen
- Plant Research Laboratory-DOE, Michigan State University, East Lansing, MI 48824, USA.
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26
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Miller-Williams M, Loewen PC, Oresnik IJ. Isolation of salt-sensitive mutants of Sinorhizobium meliloti strain Rm1021. MICROBIOLOGY-SGM 2006; 152:2049-2059. [PMID: 16804180 DOI: 10.1099/mic.0.28937-0] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The determinants necessary for adaptation to high NaCl concentrations and competition for nodule occupancy in Sinorhizobium meliloti were investigated genetically. Mutations in fabG as well as smc02909 (transmembrane transglycosylase), trigger factor (tig) and smc00717 (probably ftsE) gave rise to strains that were unable to tolerate high salt and were uncompetitive for nodule occupancy relative to the wild-type. Moreover exoF1, exoA and pgm determinants were determined to be necessary for strain Rm1021 to survive high NaCl and/or MgCl(2) concentrations. The introduction of an expR(+) allele was capable of suppressing the Mg(2+) sensitivity associated with the exoF1, but not the exoA, mutation in a manner independent of exopolysaccharide II (EPS II)-associated mucoidy. The results also show that the EPS II-associated mucoid phenotype was affected by either Mg(2+)or K(+), but not by Li(+), Ca(2+), or high osmolarity.
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Affiliation(s)
- Mark Miller-Williams
- Department of Microbiology, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Peter C Loewen
- Department of Microbiology, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Ivan J Oresnik
- Department of Microbiology, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
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27
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Abdelmoumen H, Filali‐Maltouf A, Neyra M, Belabed A, El Idrissi MM. Effect of high salts concentrations on the growth of rhizobia and responses to added osmotica. J Appl Microbiol 2001. [DOI: 10.1046/j.1365-2672.1999.00727.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- H. Abdelmoumen
- Laboratoire de Microbiologie Appliquée, Département de Biologie, Faculté des Sciences, Université Mohamed I, Oujda,
| | - A. Filali‐Maltouf
- Laboratoire de Microbiologie et de Biologie Moléculaire, Faculté des Sciences, Rabat, Morocco,
| | - M. Neyra
- Laboratoire de Microbiologie, ORSTOM, Dakar, Senegal, and
| | - A. Belabed
- Laboratoire d’Ecophysiologie et de production végétales, Département de Biologie, Faculté des Sciences, Oujda, Morocco
| | - M. Missbah El Idrissi
- Laboratoire de Microbiologie Appliquée, Département de Biologie, Faculté des Sciences, Université Mohamed I, Oujda,
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Soussi M, Santamaría M, Ocaña A, Lluch C. Effects of salinity on protein and lipopolysaccharide pattern in a salt-tolerant strain of Mesorhizobium ciceri. J Appl Microbiol 2001; 90:476-81. [PMID: 11298245 DOI: 10.1046/j.1365-2672.2001.01269.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIMS To characterize the physiological and metabolic responses of Mesorhizobium ciceri strain ch-191 to salt stress, investigating the changes induced by salinity in protein and lipopolysaccharide profiles, as well as determining the accumulation of amino acids, glutamate and proline. METHODS AND RESULTS Strain ch-191 of M. ciceri was grown with different NaCl concentrations. Protein and lipopolysaccharide patterns were determined by electrophoresis. The strain ch-191 tolerated up to 200 mmol l-1 NaCl, although higher salt dosages limited its growth and induced changes in the protein profile. The most noteworthy change in the LPS-I pattern was the decrease in the slowest band and the appearance of an intermediate mobility band. The accumulation of proline in response to salt stress surpassed that of glutamate. CONCLUSION The protein profile showed major alterations at salinity levels which inhibited growth. However, the alterations in the LPS profile and accumulation of compatible solutes were evident from the lowest levels, suggesting that these changes may constitute adaptative responses to salt, allowing normal growth. SIGNIFICANCE AND IMPACT OF THE STUDY The selection and characterization of salt-tolerant strains, which also show efficient symbiotic performance under salinity, may constitute a strategy for improving Cicer arietinum-Mesorhizobium ciceri symbiosis in adverse environments.
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Affiliation(s)
- M Soussi
- Departamento de Biología Vegetal, Facultad de Ciencias, Universidad de Granada, Spain
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29
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Lai MC, Hong TY, Gunsalus RP. Glycine betaine transport in the obligate halophilic archaeon Methanohalophilus portucalensis. J Bacteriol 2000; 182:5020-4. [PMID: 10940053 PMCID: PMC111389 DOI: 10.1128/jb.182.17.5020-5024.2000] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Transport of the osmoprotectant glycine betaine was investigated using the glycine betaine-synthesizing microbe Methanohalophilus portucalensis (strain FDF1), since solute uptake for this class of obligate halophilic methanogenic Archaea has not been examined. Betaine uptake followed a Michaelis-Menten relationship, with an observed K(t) of 23 microM and a V(max) of 8 nmol per min per mg of protein. The transport system was highly specific for betaine: choline, proline, and dimethylglycine did not significantly compete for [(14)C]betaine uptake. The proton-conducting uncoupler 2, 4-dinitrophenol and the ATPase inhibitor N, N-dicyclohexylcarbodiimide both inhibited glycine betaine uptake. Growth of cells in the presence of 500 microM betaine resulted in faster cell growth due to the suppression of the de novo synthesis of the other compatible solutes, alpha-glutamate, beta-glutamine, and N(epsilon)-acetyl-beta-lysine. These investigations demonstrate that this model halophilic methanogen, M. portucalensis strain FDF1, possesses a high-affinity and highly specific betaine transport system that allows it to accumulate this osmoprotectant from the environment in lieu of synthesizing this or other osmoprotectants under high-salt growth conditions.
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Affiliation(s)
- M C Lai
- Department of Botany, National Chung-Hsing University, Taichung, Taiwan, Republic of China.
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Choi YH, Yang CH, Kim HW, Jung S. Molecular dynamics simulations of cyclohenicosakis-[(1-->2)-beta-D-gluco-henicosapyranosyl], a cyclic (1-->2)-beta-D-glucan (a 'cyclosophoraose') of DP 21. Carbohydr Res 2000; 326:227-34. [PMID: 10903031 DOI: 10.1016/s0008-6215(00)00050-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report molecular dynamics simulations of cyclohenicosakis-[(1-->2)-beta-D-gluco-henicosapyranosyl], termed 'cyclosophohenicosamer', a member of a class of cyclic (1-->2)-beta-D-glucans ('cyclosophoraoses'). Our goals were to provide insights into the conformational preferences of these cyclosophoraoses. Simulated annealing and constant-temperature molecular dynamics calculations were performed on the DP 21 cyclosophohenicosamer. The radius of gyration (R(G)) of the molecule and the conformation of glycosidic dihedral angles were used to analyze the result of computational studies. Most glycosidic linkages were concentrated in the lowest-energy region of the phi-psi energy map, and the values of radius of gyration from our simulations were consistent with the reported experimental value. The simulations produced various types of compact and asymmetric conformations within reasonable ranges of the glycosidic linkage conformation and radius of gyration. The results indicate the presence of a high degree of molecular flexibility of cyclosophohenicosamer and suggest the uniqueness of inclusion complexation with other molecules through this molecular flexibility.
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Affiliation(s)
- Y H Choi
- Department of Chemistry, Seoul National University, South Korea
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31
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Zahran HH. Rhizobium-legume symbiosis and nitrogen fixation under severe conditions and in an arid climate. Microbiol Mol Biol Rev 1999; 63:968-89, table of contents. [PMID: 10585971 PMCID: PMC98982 DOI: 10.1128/mmbr.63.4.968-989.1999] [Citation(s) in RCA: 526] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Biological N(2) fixation represents the major source of N input in agricultural soils including those in arid regions. The major N(2)-fixing systems are the symbiotic systems, which can play a significant role in improving the fertility and productivity of low-N soils. The Rhizobium-legume symbioses have received most attention and have been examined extensively. The behavior of some N(2)-fixing systems under severe environmental conditions such as salt stress, drought stress, acidity, alkalinity, nutrient deficiency, fertilizers, heavy metals, and pesticides is reviewed. These major stress factors suppress the growth and symbiotic characteristics of most rhizobia; however, several strains, distributed among various species of rhizobia, are tolerant to stress effects. Some strains of rhizobia form effective (N(2)-fixing) symbioses with their host legumes under salt, heat, and acid stresses, and can sometimes do so under the effect of heavy metals. Reclamation and improvement of the fertility of arid lands by application of organic (manure and sewage sludge) and inorganic (synthetic) fertilizers are expensive and can be a source of pollution. The Rhizobium-legume (herb or tree) symbiosis is suggested to be the ideal solution to the improvement of soil fertility and the rehabilitation of arid lands and is an important direction for future research.
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Affiliation(s)
- H H Zahran
- Department of Botany, Faculty of Science, Beni-Suef, 62511 Egypt
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32
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Boncompagni, Osteras, Poggi, le Rudulier D. Occurrence of choline and glycine betaine uptake and metabolism in the family rhizobiaceae and their roles in osmoprotection. Appl Environ Microbiol 1999; 65:2072-7. [PMID: 10224003 PMCID: PMC91300 DOI: 10.1128/aem.65.5.2072-2077.1999] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/1998] [Accepted: 02/18/1999] [Indexed: 11/20/2022] Open
Abstract
The role of glycine betaine and choline in osmoprotection of various Rhizobium, Sinorhizobium, Mesorhizobium, Agrobacterium, and Bradyrhizobium reference strains which display a large variation in salt tolerance was investigated. When externally provided, both compounds enhanced the growth of Rhizobium tropici, Sinorhizobium meliloti, Sinorhizobium fredii, Rhizobium galegae, Agrobacterium tumefaciens, Mesorhizobium loti, and Mesorhizobium huakuii, demonstrating their utilization as osmoprotectants. However, both compounds were inefficient for the most salt-sensitive strains, such as Rhizobium leguminosarum (all biovars), Agrobacterium rhizogenes, Rhizobium etli, and Bradyrhizobium japonicum. Except for B. japonicum, all strains exhibit transport activity for glycine betaine and choline. When the medium osmolarity was raised, choline uptake activity was inhibited, whereas glycine betaine uptake was either increased in R. leguminosarum and S. meliloti or, more surprisingly, reduced in R. tropici, S. fredii, and M. loti. The transport of glycine betaine was increased by growing the cells in the presence of the substrate. With the exception of B. japonicum, all strains were able to use glycine betaine and choline as sole carbon and nitrogen sources. This catabolic function, reported for only a few soil bacteria, could increase competitiveness of rhizobial species in the rhizosphere. Choline dehydrogenase and betaine-aldehyde dehydrogenase activities were present in the cells of all strains with the exception of M. huakuii and B. japonicum. The main physiological role of glycine betaine in the family Rhizobiaceae seems to be as an energy source, while its contribution to osmoprotection is restricted to certain strains.
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Affiliation(s)
- Boncompagni
- Laboratoire de Biologie Vegetale et Microbiologie, CNRS ERS 590, Universite de Nice-Sophia Antipolis, 06108 Nice Cedex, France
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Ingram-Smith C, Miller KJ. Effects of Ionic and Osmotic Strength on the Glucosyltransferase of Rhizobium meliloti Responsible for Cyclic beta-(1,2)-Glucan Biosynthesis. Appl Environ Microbiol 1998; 64:1290-7. [PMID: 16349538 PMCID: PMC106143 DOI: 10.1128/aem.64.4.1290-1297.1998] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/1997] [Accepted: 01/20/1998] [Indexed: 11/20/2022] Open
Abstract
The cyclic beta-(1,2)-glucans of Rhizobium meliloti and Agrobacterium tumefaciens play an important role during hypoosmotic adaptation, and the synthesis of these compounds is osmoregulated. Glucosyltransferase, the enzyme responsible for cyclic beta-(1,2)-glucan biosynthesis, is present constitutively, suggesting that osmotic regulation of the biosynthesis of these glucans occurs through modulation of enzyme activity. In this study, we examined regulation of cyclic glucan biosynthesis in vitro with membrane preparations from R. meliloti. The results show that ionic solutes inhibit glucan synthesis, even when they are present at low concentrations (e.g., 10 mM). In contrast, neutral solutes (glucose, sucrose, and the compatible solutes glycine betaine and trehalose) were found to stimulate glucan synthesis in vitro when they were present at high concentrations (e.g., 1 M). Furthermore, high concentrations of these neutral solutes were shown to compensate for the inhibition of glucosyltransferase activity by ionic solutes. Consistent with their ionic character, the compatible solute potassium glutamate and the osmoprotectant choline chloride inhibited glucosyltransferase activity in vitro. The results suggest that intracellular ion concentrations, intracellular osmolarity, and intracellular concentrations of nonionic compatible solutes all act as important determinants of glucosyltransferase activity in vivo. Additional experiments were performed with an ndvA mutant defective for transport of cyclic glucans and an ndvB mutant that produces a C-terminal truncated glucosyltransferase. Cyclic beta-(1,2)-glucan biosynthesis, although reduced, was found to be osmoregulated in both mutants. These results reveal that NdvA and the C terminus of NdvB are not required for osmotic regulation of cyclic beta-(1,2)-glucan biosynthesis.
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Affiliation(s)
- C Ingram-Smith
- Department of Food Science and Graduate Programs in Plant Physiology and Genetics, The Pennsylvania State University, University Park, Pennsylvania 16802
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Xu X, Abo M, Okubo A, Yamazaki S. Trehalose as osmoprotectant in Rhodobacter sphaeroides f. sp. denitrificans IL106. Biosci Biotechnol Biochem 1998; 62:334-7. [PMID: 9532791 DOI: 10.1271/bbb.62.334] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The photosynthetic bacterium Rhodobacter sphaeroides f. sp. denitrificans IL106 can grow in high osmolarity. The accumulation of intracellular inorganic ions and organic solutes in cells grown in a synthetic medium containing different concentrations of NaCl was examined. Together with potassium ion, trehalose was the major organic osmoprotectant and its accumulation depended on the external salt concentration. Intracellular levels of glycine betaine and other osmoprotectants such as proline did not change when osmolarity increased.
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Affiliation(s)
- X Xu
- Department of Applied Biological Chemistry, University of Tokyo, Japan
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35
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Abstract
The osmolality of rhizosphere soil water is expected to be elevated in relation to bulk-soil water osmolality as a result of the exclusion of solutes by plant roots during water uptake, the release of plant root exudates, and the production of exopolymers by plant roots and rhizobacteria. In contrast, the osmolality of water within highly hydrated bulk soil is low (less than 50 Osm/kg); thus the ability to adapt to elevated osmolality is likely to be important for successful rhizosphere colonization by rhizobacteria. The present review focuses on the osmoadaptive responses of three gram-negative rhizobacterial genera: Rhizobium, Azospirillum, and Pseudomonas. Specifically, we examine the compatible solutes and osmoprotectants utilized by various species within these genera. The adaptation of rhizobacteria to hypoosmotic environments is also examined in the present review. In particular, we focus on the biosynthesis and accumulation of periplasmic glucans by rhizobacteria. Finally, the relationship between rhizobacterial osmoadaptation and selected plant-microbe interactions is considered.
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Affiliation(s)
- K J Miller
- Department of Food Science, Pennsylvania State University, University Park 16802, USA
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36
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Lloret J, Bolanos L, Lucas MM, Peart JM, Brewin NJ, Bonilla I, Rivilla R. Ionic Stress and Osmotic Pressure Induce Different Alterations in the Lipopolysaccharide of a Rhizobium meliloti Strain. Appl Environ Microbiol 1995; 61:3701-4. [PMID: 16535151 PMCID: PMC1388713 DOI: 10.1128/aem.61.10.3701-3704.1995] [Citation(s) in RCA: 78] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A halotolerant strain of Rhizobium meliloti was isolated from nodules of a Melilotus plant growing in a salt marsh in Donana National Park (southwest Spain). This strain, EFB1, is able to grow at NaCl concentrations of up to 500 mM, and no effect on growth is produced by 300 mM NaCl. EFB1 showed alterations on its lipopolysaccharide (LPS) structure that can be related to salt stress: (i) silver-stained electrophoretic profiles showed a different mobility that was dependent on ionic stress but not on osmotic pressure, and (ii) a monoclonal antibody, JIM 40, recognized changes in LPS that were dependent on osmotic stress. Both modifications on LPS may form part of the adaptive mechanism of this bacterium for saline environments.
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Nunes OC, Manaia CM, Da Costa MS, Santos H. Compatible Solutes in the Thermophilic Bacteria Rhodothermus marinus and "Thermus thermophilus". Appl Environ Microbiol 1995; 61:2351-7. [PMID: 16535053 PMCID: PMC1388471 DOI: 10.1128/aem.61.6.2351-2357.1995] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
(sup13)C nuclear magnetic resonance spectroscopy and (sup1)H nuclear magnetic resonance spectroscopy were used to identify and quantify the organic solutes of several strains of halophilic or halotolerant thermophilic bacteria. Two strains of Rhodothermus marinus and four strains of "Thermus thermophilus" grown in complex medium containing NaCl were examined. 2-O-Mannosylglycerate was a major compatible solute in all strains: the Thermus strains accumulated the (beta)-anomer only, whereas both anomers were found in R. marinus. 2-O-(beta)-mannosylglycerate and 2-O-(alpha)-mannosylglycerate were the major compatible solutes in R. marinus. The former was the predominant solute in cells grown in 2.0 and 4.0% NaCl-containing medium, while the latter was the predominant compatible solute at higher salinities. Glutamate, trehalose, and glucose were also present as minor components. The intracellular K(sup+) concentration, as determined by (sup39)K nuclear magnetic resonance spectroscopy, in R. marinus increased with salinity and was sufficient to balance the negative charges of the mannosylglycerate. In addition to 2-O-(beta)-mannosylglycerate, trehalose was a major compatible solute of "T. thermophilus." 2-O-(beta)-Mannosylglycerate was the main solute in medium containing 1.0 or 2.0% NaCl, while trehalose predominated in cells grown in medium supplemented with 3.0 or 4.0% NaCl. Glycine betaine, in lower concentrations, was also detected in two "T. thermophilus" strains. This is the first report of mannosylglycerate as a compatible solute in bacteria.
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Talibart R, Jebbar M, Gouesbet G, Himdi-Kabbab S, Wróblewski H, Blanco C, Bernard T. Osmoadaptation in rhizobia: ectoine-induced salt tolerance. J Bacteriol 1994; 176:5210-7. [PMID: 8071195 PMCID: PMC196703 DOI: 10.1128/jb.176.17.5210-5217.1994] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
After having shown that ectoine (a tetrahydropyrimidine) displays osmoprotective properties towards Escherichia coli (M. Jebbar, R. Talibart, K. Gloux, T. Bernard, and Blanco, J. Bacteriol. 174:5027-5035, 1992), we have investigated the involvement of this molecule in the osmotic adaptation of Rhizobium meliloti. Ectoine appeared almost as effective as glycine betaine in improving the growth of R. meliloti under adverse osmotic conditions (0.5 M NaCl). Moreover, improvement of growth of rhizobial strains insensitive to glycine betaine was also observed. Ectoine transport proved inducible, periplasmic protein dependent, and, as shown by competition experiments, distinct from the transport of glycine betaine. Medium osmolarity had little effect on the uptake characteristics, since the rate of influx increased from 12 to only 20 nmol min-1 mg of protein-1 when NaCl concentrations were raised from 0 to 0.3 or 0.5 M, with a constant of transport of 80 microM. Natural-abundance 13C-nuclear magnetic resonance and radiolabelling assays showed that ectoine, unlike glycine betaine, is not intracellularly accumulated and, as a consequence, does not repress the synthesis of endogenous compatible solutes (glutamate, N-acetylglutaminylglutamine amide, and trehalose). Furthermore, the strong rise in glutamate content in cells osmotically stressed in the presence of ectoine suggests that, instead of being involved in osmotic balance restoration, ectoine should play a key role in triggering the synthesis of endogenous osmolytes. Hence, we believe that there are at least two distinct classes of osmoprotectants: those such as glycine betaine or glutamate, which act as genuine osmolytes, and those such as ectoine, which act as chemical mediators.
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Affiliation(s)
- R Talibart
- Département Membranes et Osmorégulation, Centre National de la Recherche Scientifique (CNRS) URA 256, Rennes, France
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Botsford JL, Alvarez M, Hernandez R, Nichols R. Accumulation of glutamate by Salmonella typhimurium in response to osmotic stress. Appl Environ Microbiol 1994; 60:2568-74. [PMID: 7915510 PMCID: PMC201685 DOI: 10.1128/aem.60.7.2568-2574.1994] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Salmonella typhimurium accumulates glutamate in response to osmotic stress. Cells in aerobic exponential growth have an intracellular pool of approximately 125 nmol of glutamate mg of protein-1. When cells were grown in minimal medium with 500 mM NaCl, KCl, or sucrose, 290 to 430 nmol of glutamate was found to accumulate. Values were lower when cells were harvested in stationary phase. Cells were grown in conventional medium, harvested, washed, resuspended in the control medium or in medium with osmolytes, and aerated for 1 h. With aeration, glutamate was found to accumulate at levels comparable to those observed in exponential cultures. Antibiotics inhibiting protein synthesis did not affect glutamate accumulation when cells were aerated. Strains with mutations in glutamate synthase (glt) or in glutamate dehydrogenase (gdh) accumulated nearly normal levels of glutamate under these conditions. A double (gdh glt) mutant accumulated much less glutamate (63.9 nmol mg of protein-1), but a 1.9-fold excess accumulated when cells were aerated with osmotic stress. Methionine sulfone, an inhibitor of glutamate synthase, did not prevent accumulation of glutamate in cells aerated with osmotic stress. Glutamate dehydrogenase is thought to have minimum activity when ammonium is limiting. Resuspending cells with limiting ammonium reduced glutamate production but did not eliminate accumulation of excess glutamate when cells were osmotically stressed. Amino oxyacetic acid, an inhibitor of transamination reactions, did not prevent accumulation of excess glutamate.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- J L Botsford
- Department of Biology, New Mexico State University, Las Cruces 88003
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40
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Elucidation of the role of osmoprotective compounds and osmoregulatory genes: The key role of bacteria. ACTA ACUST UNITED AC 1993. [DOI: 10.1007/978-94-011-1858-3_34] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/20/2023]
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41
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Chien CT, Maundu J, Cavaness J, Dandurand LM, Orser CS. Characterization of salt-tolerant and salt-sensitive mutants ofRhizobium leguminosarumbiovarviciaestrain C1204b. FEMS Microbiol Lett 1992. [DOI: 10.1111/j.1574-6968.1992.tb05140.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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42
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Zevenhuizen LP. Levels of trehalose and glycogen in Arthrobacter globiformis under conditions of nutrient starvation and osmotic stress. Antonie Van Leeuwenhoek 1992; 61:61-8. [PMID: 1575469 DOI: 10.1007/bf00572124] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Cells of Arthrobacter globiformis grown in carbohydrate-rich media were found to contain large quantities of low-Mr carbohydrates (800 micrograms/mg protein) and only small amounts of amino acids, in addition to high amounts of glycogen (2 mg/mg protein). At increasing osmotic values of the medium, low-Mr carbohydrate levels increased to 1300 micrograms/mg protein. Low-Mr pools were extracted from the cells with hot 75% ethanol, and subjected to thin layer, gel and gas-liquid chromatography. They turned out to consist mainly of alpha,alpha-trehalose. Levels of trehalose in Arthrobacter cells have the tendency to remain constant, both during nutrient exhaustion (resulting in glycogen consumption), and on addition of excess of carbon source to the medium (resulting in an increased glycogen content of the cells). The stress-tolerant properties of Arthrobacter (resistance to nutrient starvation, desiccation and high salt concentration) are discussed with respect to the high glycogen and trehalose contents of the cells.
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Affiliation(s)
- L P Zevenhuizen
- Laboratory of Microbiology, Agricultural University, Wageningen, The Netherlands
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43
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Chine-Te-Chien, Shetty K, Mortimer M, Orser CS. Calcium-induced salt tolerance inRhizobium leguminosarumbiovarviciaestrain C124b. FEMS Microbiol Lett 1991. [DOI: 10.1111/j.1574-6968.1991.tb04443.x-i1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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Lewis TA, Gonzalez R, Botsford JL. Rhizobium meliloti glutamate synthase: cloning and initial characterization of the glt locus. J Bacteriol 1990; 172:2413-20. [PMID: 2185218 PMCID: PMC208877 DOI: 10.1128/jb.172.5.2413-2420.1990] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The genetic locus glt, encoding glutamate synthase from Rhizobium meliloti 1021, was selected from a pLAFR1 clone bank by complementation of the R. meliloti 41 Glt- mutant AK330. A fragment of cloned DNA complementing this mutant also served to complement the Escherichia coli glt null mutant PA340. Complementation studies using these mutants suggested that glutamate synthase expression requires two complementation groups present at this locus. Genomic Southern analysis using a probe of the R. meliloti 1021 glt region showed a close resemblance between R. meliloti 1021, 41, and 102f34 at glt, whereas R. meliloti 104A14 showed many differences in restriction fragment length polymorphism patterns at this locus. R. meliloti 102f34, but not the other strains, showed an additional region with sequence similarity to glt. Insertion alleles containing transposable kanamycin resistance elements were constructed and used to derive Glt- mutants of R. meliloti 1021 and 102f34. These mutants were unable to assimilate ammonia and were Nod+ Fix+ on alfalfa seedlings. The mutants also showed poor or no growth on nitrogen sources such as glutamate, aspartate, arginine, and histidine, which are utilized by the wild-type parental strains. Strains that remained auxotrophic but grew nearly as well as the wild type on these nitrogen sources were readily isolated from populations of glt insertion mutants, indicating that degradation of these amino acids is negatively regulated in R. meliloti as a result of disruptions of glt.
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Affiliation(s)
- T A Lewis
- Department of Biology, New Mexico State University, Las Cruces 88003
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