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Yamada M. Molecular basis and functional development of membrane-based microbial metabolism. Biosci Biotechnol Biochem 2024; 88:461-474. [PMID: 38366612 DOI: 10.1093/bbb/zbae018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Accepted: 02/07/2024] [Indexed: 02/18/2024]
Abstract
My research interest has so far been focused on metabolisms related to the "membrane" of microorganisms, such as the respiratory chain, membrane proteins, sugar uptake, membrane stress and cell lysis, and fermentation. These basic metabolisms are important for the growth and survival of cell, and their knowledge can be used for efficient production of useful materials. Notable achievements in research on metabolisms are elucidation of the structure and function of membrane-bound glucose dehydrogenase as a primary enzyme in the respiratory chain, elucidation of ingenious expression regulation of several operons or by divergent promoters, elucidation of stress-induced programed-cell lysis and its requirement for survival during a long-term stationary phase, elucidation of molecular mechanism of survival at a critical high temperature, elucidation of thermal adaptation and its limit, isolation of thermotolerant fermenting yeast strains, and development of high-temperature fermentation and green energy production technologies. These achievements are described together in this review.
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Affiliation(s)
- Mamoru Yamada
- Graduate School of Sciences and Technology for Innovation, and Research Center for Thermotolerant Microbial Resources, Yamaguchi University, Yamaguchi, Japan
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2
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Maitra A, Munshi T, Healy J, Martin LT, Vollmer W, Keep NH, Bhakta S. Cell wall peptidoglycan in Mycobacterium tuberculosis: An Achilles' heel for the TB-causing pathogen. FEMS Microbiol Rev 2020; 43:548-575. [PMID: 31183501 PMCID: PMC6736417 DOI: 10.1093/femsre/fuz016] [Citation(s) in RCA: 97] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 06/07/2019] [Indexed: 02/06/2023] Open
Abstract
Tuberculosis (TB), caused by the intracellular pathogen Mycobacterium tuberculosis, remains one of the leading causes of mortality across the world. There is an urgent requirement to build a robust arsenal of effective antimicrobials, targeting novel molecular mechanisms to overcome the challenges posed by the increase of antibiotic resistance in TB. Mycobacterium tuberculosis has a unique cell envelope structure and composition, containing a peptidoglycan layer that is essential for maintaining cellular integrity and for virulence. The enzymes involved in the biosynthesis, degradation, remodelling and recycling of peptidoglycan have resurfaced as attractive targets for anti-infective drug discovery. Here, we review the importance of peptidoglycan, including the structure, function and regulation of key enzymes involved in its metabolism. We also discuss known inhibitors of ATP-dependent Mur ligases, and discuss the potential for the development of pan-enzyme inhibitors targeting multiple Mur ligases.
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Affiliation(s)
- Arundhati Maitra
- Mycobacteria Research Laboratory, Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, Malet Street, London WC1E 7HX, UK
| | - Tulika Munshi
- Mycobacteria Research Laboratory, Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, Malet Street, London WC1E 7HX, UK
| | - Jess Healy
- Department of Pharmaceutical and Biological Chemistry, UCL School of Pharmacy, 29-39 Brunswick Square, London WC1N 1AX, UK
| | - Liam T Martin
- Mycobacteria Research Laboratory, Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, Malet Street, London WC1E 7HX, UK
| | - Waldemar Vollmer
- The Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Richardson Road, Newcastle upon Tyne, NE2 4AX, UK
| | - Nicholas H Keep
- Mycobacteria Research Laboratory, Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, Malet Street, London WC1E 7HX, UK
| | - Sanjib Bhakta
- Mycobacteria Research Laboratory, Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, Malet Street, London WC1E 7HX, UK
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3
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Chaithawiwat K, Vangnai A, McEvoy JM, Pruess B, Krajangpan S, Khan E. Role of oxidative stress in inactivation of Escherichia coli BW25113 by nanoscale zero-valent iron. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 565:857-862. [PMID: 26953142 DOI: 10.1016/j.scitotenv.2016.02.191] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 02/26/2016] [Accepted: 02/27/2016] [Indexed: 06/05/2023]
Abstract
An Escherichia coli BW25113 wildtype strain and mutant strains lacking genes that protect against oxidative stress were examined at different growth phases for susceptibility to zero-valent iron (nZVI). Viability of cells was determined by the plate count method. All mutant strains were more susceptible than the wild type strain to nZVI; however, susceptibility differed among the mutant strains. Consistent with the role of rpoS as a global stress regulator, an rpoS gene knockout mutant exhibited the greatest susceptibility to nZVI under the majority of conditions tested (except exponential and declining phases at longer exposure time). Mutants lacking genes encoding the inducible and constitutively expressed cytosolic superoxide dismutases, sodA and sodB, respectively, were more susceptible to nZVI than a mutant lacking the gene encoding sodC, a periplasmic superoxide dismutase. This suggests that nZVI induces oxidative stress inside the cells via superoxide generation. Quantitative polymerase chain reaction was used to examine the expression of katG, a gene encoding the catalase-peroxidase enzyme, in nZVI-treated E. coli at different growth phases. Results showed that nZVI repressed the expression of katG in all but lag phases.
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Affiliation(s)
- Krittanut Chaithawiwat
- International Postgraduate Programs in Environmental Management, Graduate School Chulalongkorn University, Bangkok 10330, Thailand; Environmental and Conservation Sciences, North Dakota State University, Fargo, ND 58108, USA
| | - Alisa Vangnai
- Department of Biochemistry, Chulalongkorn University, Bangkok 10330, Thailand
| | - John M McEvoy
- Department of Veterinary and Microbiological Sciences, North Dakota State University, Fargo, ND 58108, USA
| | - Birgit Pruess
- Department of Veterinary and Microbiological Sciences, North Dakota State University, Fargo, ND 58108, USA
| | | | - Eakalak Khan
- Department of Civil and Environmental Engineering, North Dakota State University, Fargo, ND 58108, USA.
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4
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Fröhlich KS, Haneke K, Papenfort K, Vogel J. The target spectrum of SdsR small RNA in Salmonella. Nucleic Acids Res 2016; 44:10406-10422. [PMID: 27407104 PMCID: PMC5137417 DOI: 10.1093/nar/gkw632] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 06/11/2016] [Accepted: 06/29/2016] [Indexed: 12/28/2022] Open
Abstract
Model enteric bacteria such as Escherichia coli and Salmonella enterica express hundreds of small non-coding RNAs (sRNAs), targets for most of which are yet unknown. Some sRNAs are remarkably well conserved, indicating that they serve cellular functions that go beyond the necessities of a single species. One of these ‘core sRNAs’ of largely unknown function is the abundant ∼100-nucleotide SdsR sRNA which is transcribed by the general stress σ-factor, σS and accumulates in stationary phase. In Salmonella, SdsR was known to inhibit the synthesis of the species-specific porin, OmpD. However, sdsR genes are present in almost all enterobacterial genomes, suggesting that additional, conserved targets of this sRNA must exist. Here, we have combined SdsR pulse-expression with whole genome transcriptomics to discover 20 previously unknown candidate targets of SdsR which include mRNAs coding for physiologically important regulators such as the carbon utilization regulator, CRP, the nucleoid-associated chaperone, StpA and the antibiotic resistance transporter, TolC. Processing of SdsR by RNase E results in two cellular SdsR variants with distinct target spectra. While the overall physiological role of this orphan core sRNA remains to be fully understood, the new SdsR targets present valuable leads to determine sRNA functions in resting bacteria.
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Affiliation(s)
- Kathrin S Fröhlich
- RNA Biology Group, Institute for Molecular Infection Biology, University of Würzburg, Josef-Schneider-Straße 2, D-97080 Würzburg, Germany.,Department of Biology I, Microbiology, Ludwig-Maximilians-University Munich, D-82152 Martinsried, Germany
| | - Katharina Haneke
- RNA Biology Group, Institute for Molecular Infection Biology, University of Würzburg, Josef-Schneider-Straße 2, D-97080 Würzburg, Germany
| | - Kai Papenfort
- Department of Biology I, Microbiology, Ludwig-Maximilians-University Munich, D-82152 Martinsried, Germany
| | - Jörg Vogel
- RNA Biology Group, Institute for Molecular Infection Biology, University of Würzburg, Josef-Schneider-Straße 2, D-97080 Würzburg, Germany
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5
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Liu X, Hu W, An Z, Bai Z, Dai X, Yang Y. Exploration of cell lysis in a bioreactor using Escherichia coli expressing single-chain variable-domain antibody fragments. ANN MICROBIOL 2016. [DOI: 10.1007/s13213-016-1202-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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6
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Zhang L, Xiao D, Pang B, Zhang Q, Zhou H, Zhang L, Zhang J, Kan B. The core proteome and pan proteome of Salmonella Paratyphi A epidemic strains. PLoS One 2014; 9:e89197. [PMID: 24586590 PMCID: PMC3933413 DOI: 10.1371/journal.pone.0089197] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Accepted: 01/15/2014] [Indexed: 01/08/2023] Open
Abstract
Comparative proteomics of the multiple strains within the same species can reveal the genetic variation and relationships among strains without the need to assess the genomic data. Similar to comparative genomics, core proteome and pan proteome can also be obtained within multiple strains under the same culture conditions. In this study we present the core proteome and pan proteome of four epidemic Salmonella Paratyphi A strains cultured under laboratory culture conditions. The proteomic information was obtained using a Two-dimensional gel electrophoresis (2-DE) technique. The expression profiles of these strains were conservative, similar to the monomorphic genome of S. Paratyphi A. Few strain-specific proteins were found in these strains. Interestingly, non-core proteins were found in similar categories as core proteins. However, significant fluctuations in the abundance of some core proteins were also observed, suggesting that there is elaborate regulation of core proteins in the different strains even when they are cultured in the same environment. Therefore, core proteome and pan proteome analysis of the multiple strains can demonstrate the core pathways of metabolism of the species under specific culture conditions, and further the specific responses and adaptations of the strains to the growth environment.
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Affiliation(s)
- Li Zhang
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, P. R. China
| | - Di Xiao
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, P. R. China
| | - Bo Pang
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, P. R. China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, P.R.China
| | - Qian Zhang
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, P. R. China
| | - Haijian Zhou
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, P. R. China
| | - Lijuan Zhang
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, P. R. China
| | - Jianzhong Zhang
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, P. R. China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, P.R.China
| | - Biao Kan
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, P. R. China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, P.R.China
- * E-mail:
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7
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Rittershaus ESC, Baek SH, Sassetti CM. The normalcy of dormancy: common themes in microbial quiescence. Cell Host Microbe 2013; 13:643-51. [PMID: 23768489 DOI: 10.1016/j.chom.2013.05.012] [Citation(s) in RCA: 216] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
All microorganisms are exposed to periodic stresses that inhibit growth. Many bacteria and fungi weather these periods by entering a hardy, nonreplicating state, often termed quiescence or dormancy. When this occurs during an infection, the resulting slowly growing pathogen is able to tolerate both immune insults and prolonged antibiotic exposure. While the stresses encountered in a free-living environment may differ from those imposed by host immunity, these growth-limiting conditions impose common pressures, and many of the corresponding microbial responses appear to be universal. In this review, we discuss the common features of these growth-limited states, which suggest new approaches for treating chronic infections such as tuberculosis.
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Affiliation(s)
- Emily S C Rittershaus
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA 01655, USA
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8
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How bacteria consume their own exoskeletons (turnover and recycling of cell wall peptidoglycan). Microbiol Mol Biol Rev 2008; 72:211-27, table of contents. [PMID: 18535144 DOI: 10.1128/mmbr.00027-07] [Citation(s) in RCA: 305] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
SUMMARY The phenomenon of peptidoglycan recycling is reviewed. Gram-negative bacteria such as Escherichia coli break down and reuse over 60% of the peptidoglycan of their side wall each generation. Recycling of newly made peptidoglycan during septum synthesis occurs at an even faster rate. Nine enzymes, one permease, and one periplasmic binding protein in E. coli that appear to have as their sole function the recovery of degradation products from peptidoglycan, thereby making them available for the cell to resynthesize more peptidoglycan or to use as an energy source, have been identified. It is shown that all of the amino acids and amino sugars of peptidoglycan are recycled. The discovery and properties of the individual proteins and the pathways involved are presented. In addition, the possible role of various peptidoglycan degradation products in the induction of beta-lactamase is discussed.
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9
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Kabir MS, Yamashita D, Koyama S, Oshima T, Kurokawa K, Maeda M, Tsunedomi R, Murata M, Wada C, Mori H, Yamada M. Cell lysis directed by sigmaE in early stationary phase and effect of induction of the rpoE gene on global gene expression in Escherichia coli. MICROBIOLOGY-SGM 2005; 151:2721-2735. [PMID: 16079349 DOI: 10.1099/mic.0.28004-0] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
It has been shown that Escherichia coli cells with increased expression of the rpoE gene encoding sigma(E) exhibit enhanced cell lysis in early stationary phase. Further analysis of the lysis phenomenon was performed using a transient expression system of the rpoE gene and by DNA microarray. The former analysis revealed a sigma(E)-directed cell lysis, specific for early stationary phase but not for the exponential phase. The microarray analysis with RNAs from exponential and early stationary phase cells revealed that a large number of genes were up- or down-regulated when the rpoE gene was induced, and that several genes were induced in a phase-specific manner. The upregulated genes include many previously identified sigma(E) regulon genes, suggesting that a large number of genes are under the control of sigma(E) in this organism. These genes are involved in various cellular activities, including the cell envelope, cellular processes, regulatory functions, transport and translation. Genes that are presumably related to phase-specific cell lysis in E. coli are discussed.
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Affiliation(s)
- Md Shahinur Kabir
- Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8515, Japan
| | - Daisuke Yamashita
- Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8515, Japan
| | - Satoshi Koyama
- Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8515, Japan
| | - Taku Oshima
- Graduate School of Information Science, Nara Institute of Science and Technology, Nara 630-01, Japan
| | - Ken Kurokawa
- Graduate School of Information Science, Nara Institute of Science and Technology, Nara 630-01, Japan
| | - Maki Maeda
- R&E Center of Informatics, Nara Institute of Science and Technology, Nara 630-01, Japan
| | - Ryouichi Tsunedomi
- Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8515, Japan
| | - Masayuki Murata
- Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8515, Japan
| | - Chieko Wada
- Laboratory of Plasma Membrane and Nuclear Signalling, Graduate School of Biostudies, 1302, Kyoto University, Kyoto 606-8502, Japan
- CREST, Nara Institute of Science and Technology, Nara 630-01, Japan
| | - Hirotada Mori
- R&E Center of Informatics, Nara Institute of Science and Technology, Nara 630-01, Japan
- CREST, Nara Institute of Science and Technology, Nara 630-01, Japan
| | - Mamoru Yamada
- Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8515, Japan
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Talukder AA, Yanai S, Yamada M. Analysis of reading frame and expressional regulation of randomly selected promoter-proximal genes in Escherichia coli. J GEN APPL MICROBIOL 2005; 51:93-103. [PMID: 15942870 DOI: 10.2323/jgam.51.93] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The expression of seventy-seven randomly cloned genes of Escherichia coli was examined following a variety of treatments including heat shock, glucose starvation, phosphate starvation, ammonium starvation or osmotic shock, with the aid of lacZ reporter gene protein fusions on multicopy plasmids. Two of 77 genes (amr and yigL) had not previously been identified as protein encoding open-reading frames (ORFs) in annotations of the E. coli genome database. Thirteen genes exhibited significant changes in expression in response to at least one of the treatments, and six of them appeared to be controlled by more than one sigma (sigma) factor of RNA polymerase. This study thus allows us not only to identify the reading frame of the genomic genes but also to support the hypothesis earlier proposed that a significant proportion of genes in E. coli are involved in adaptations to various stresses to which the organism is likely to be exposed in the environment.
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Affiliation(s)
- Ali Azam Talukder
- Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Yamaguchi, Japan.
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11
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Kabir MS, Sagara T, Oshima T, Kawagoe Y, Mori H, Tsunedomi R, Yamada M. Effects of mutations in the rpoS gene on cell viability and global gene expression under nitrogen starvation in Escherichia coli. MICROBIOLOGY-SGM 2004; 150:2543-2553. [PMID: 15289551 DOI: 10.1099/mic.0.27012-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Escherichia coli bearing an rpoS amber or disrupted mutation exhibited a significant decrease in the number of colony-forming units (c.f.u.) when exposed to nitrogen starvation, which was not observed in cells bearing a functional rpoS allele. The decrease in the number of c.f.u. that was observed about 25 h after initiation of nitrogen starvation was prevented by the addition of nitrogen within 3 h but not by the addition of nitrogen at more than 7 h after the initiation of nitrogen starvation, suggesting that a process leading to a decline in c.f.u. starts within this period. DNA microarray analysis of the rpoS mutant showed that a large number of genes including many functionally undefined genes were affected by nitrogen starvation. The expression levels of sigma(S) and sigma(H) regulon genes encoding acid-resistant proteins (hdeA, hdeB, gadA and gadB), DNA-binding protein (dps), chaperones (dnaK, ibpA, ibpB, dnaJ and htpG), chaperonins (mopB and mopA) and energy-metabolism-related proteins (hyaABCDF and gapA), and those of other genes encoding nucleotide-metabolism-related proteins (deoC and deoB), cell-division protein (ftsL), outer-membrane lipoprotein (slp) and DNA-binding protein (stpA) were significantly decreased by 10 h nitrogen starvation. The genes encoding transport/binding proteins (nac, amtB, argT, artJ, potF and hisJ) and amino acid-metabolism-related proteins (glnA, trpB, argG, asnB, argC, gdhA, cstC, ntrB, asd and lysC) were significantly up-regulated under the same condition, some of which are known Ntr genes expressed under nitrogen limitation. On the basis of these results, possible causes of the decrease in the number of c.f.u. under nitrogen starvation are discussed.
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Affiliation(s)
- Md Shahinur Kabir
- Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8515, Japan
| | - Takehiro Sagara
- Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8515, Japan
| | - Taku Oshima
- R&E Center of Informatics, Nara Institute of Science and Technology, Nara 630-01, Japan
- CREST, Nara Institute of Science and Technology, Nara 630-01, Japan
| | - Yuya Kawagoe
- R&E Center of Informatics, Nara Institute of Science and Technology, Nara 630-01, Japan
| | - Hirotada Mori
- R&E Center of Informatics, Nara Institute of Science and Technology, Nara 630-01, Japan
- CREST, Nara Institute of Science and Technology, Nara 630-01, Japan
| | - Ryouichi Tsunedomi
- Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8515, Japan
| | - Mamoru Yamada
- Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8515, Japan
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12
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Saumaa S, Tover A, Kasak L, Kivisaar M. Different spectra of stationary-phase mutations in early-arising versus late-arising mutants of Pseudomonas putida: involvement of the DNA repair enzyme MutY and the stationary-phase sigma factor RpoS. J Bacteriol 2002; 184:6957-65. [PMID: 12446646 PMCID: PMC135458 DOI: 10.1128/jb.184.24.6957-6965.2002] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2002] [Accepted: 09/17/2002] [Indexed: 11/20/2022] Open
Abstract
Stationary-phase mutations occur in populations of stressed, nongrowing, and slowly growing cells and allow mutant bacteria to overcome growth barriers. Mutational processes in starving cells are different from those occurring in growing bacteria. Here, we present evidence that changes in mutational processes also take place during starvation of bacteria. Our test system for selection of mutants based on creation of functional promoters for the transcriptional activation of the phenol degradation genes pheBA in starving Pseudomonas putida enables us to study base substitutions (C-to-A or G-to-T transversions), deletions, and insertions. We observed changes in the spectrum of promoter-creating mutations during prolonged starvation of Pseudomonas putida on phenol minimal plates. One particular C-to-A transversion was the prevailing mutation in starving cells. However, with increasing time of starvation, the importance of this mutation decreased but the percentage of other types of mutations, such as 2- to 3-bp deletions, increased. The rate of transversions was markedly elevated in the P. putida MutY-defective strain. The occurrence of 2- to 3-bp deletions required the stationary-phase sigma factor RpoS, which indicates that some mutagenic pathway is positively controlled by RpoS in P. putida.
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Affiliation(s)
- Signe Saumaa
- Department of Genetics, Institute of Molecular and Cell Biology, Tartu University and Estonian Biocentre, Estonia
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13
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Corchero JL, Cubarsí R, Vila P, Arís A, Villaverde A. Cell lysis in Escherichia coli cultures stimulates growth and biosynthesis of recombinant proteins in surviving cells. Microbiol Res 2001; 156:13-8. [PMID: 11372648 DOI: 10.1078/0944-5013-00066] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Cell growth and production of recombinant proteins in stationary phase cultures of Escherichia coli recover concomitantly with spontaneous lysis of a fraction of the ageing cell population. Further exploration of this event has indicated that sonic cell disruption stimulates both cell growth and synthesis of plasmid-encoded recombinant proteins, even in exponentially growing cultures. These observations indicate an efficient cell utilisation of released intracellular material and also that this capability is not restricted to extreme nutrient-starving conditions. In addition, the efficient re-conversion of waste cell material can be viewed as a potential strategy for an extreme exploitation of carbon sources and cell metabolites in production processes of both recombinant and non-recombinant microbial products.
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Affiliation(s)
- J L Corchero
- Institut de Biologia Fonamental and Departament de Genètica i Microbiologia, Universitat Autònoma de Barcelona, Bellaterra, Spain
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14
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Ramirez E, Carbonell X, Villaverde A. Phage spread dynamics in clonal bacterial populations is depending on features of the founder cell. Microbiol Res 2001; 156:35-40. [PMID: 11372651 DOI: 10.1078/0944-5013-00087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Plate-cultured bacterial colonies are intriguing models to study host-parasite interactions in senescent populations. During the growth of bacteriophage-infected colonies there is a synchronous prophage induction episode among lysogenic cells that allows a dramatic but time-restricted amplification of viral particles. We report here that the dynamics of phage spread depends on the history of the lysogenic cell that establishes the clonal population, the duration of the pre-burst period being shorter when the founder, infected cell derives from older colonies. These results offer a physiologic explanation for the self-contained progression of the viral spread in closed environments, that ensures both viral dissemination but also survival of most of the host cells.
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Affiliation(s)
- E Ramirez
- Institut de Biologia Fonamental and Departament de Genètica i Microbiologia, Universitat Autònoma de Barcelona, Bellaterra, Spain
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15
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Ševčı K MR, Šebková A, Volf J, Rychlı K I. Transcription of arcA and rpoS during growth of Salmonella typhimurium under aerobic and microaerobic conditions. MICROBIOLOGY (READING, ENGLAND) 2001; 147:701-708. [PMID: 11238977 DOI: 10.1099/00221287-147-3-701] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Physiology of the exponential and stationary phase of growth, under both aerobic and microaerobic conditions, of Salmonella typhimurium and its isogenic mutants nuoG::Km, cydA::TnphoA, DeltaarcA and DeltarpoS was studied using luxAB transcriptional fusions with the rpoS and arcA genes. In the wild-type strain, rpoS transcription was greater under aerobic than under microaerobic conditions, whereas transcription of arcA was suppressed by aerobiosis. Under aerobic conditions, no interaction between NuoG, CydA, ArcA and RpoS was detected. Under microaerobic conditions, rpoS was suppressed in the nuoG mutant as compared with the wild-type strain, but it was overexpressed in the cydA and arcA mutants. A deletion in the rpoS gene, on the other hand, resulted in non-restricted, increased arcA expression in stationary-phase cultures under microaerobic conditions. Based on the rpoS transcription in the nuoG mutant the authors propose that the decrease in the NADH:NAD ratio that occurs when carbon sources become limiting serves as a signal for increased rpoS transcription, while active respiration catalysed by CydA and controlled by ArcA downregulates rpoS transcription. When, finally, the RpoS-controlled stationary phase of growth is reached, arcA is suppressed in an RpoS-dependent fashion. Transition into stationary phase under microaerobic conditions is thus controlled by coordinated action of the RpoS and ArcA regulators, depending on subtle changes in the environment.
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Affiliation(s)
- Mojmı R Ševčı K
- Veterinary Research Institute, Hudcova 70, 621 32 Brno, Czech Republic1
| | - Alena Šebková
- Veterinary Research Institute, Hudcova 70, 621 32 Brno, Czech Republic1
| | - Jiřı Volf
- Veterinary Research Institute, Hudcova 70, 621 32 Brno, Czech Republic1
| | - Ivan Rychlı K
- Veterinary Research Institute, Hudcova 70, 621 32 Brno, Czech Republic1
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Yamada M, Talukder AA, Nitta T. Characterization of the ssnA gene, which is involved in the decline of cell viability at the beginning of stationary phase in Escherichia coli. J Bacteriol 1999; 181:1838-46. [PMID: 10074077 PMCID: PMC93583 DOI: 10.1128/jb.181.6.1838-1846.1999] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
When grown in rich medium, Escherichia coli exhibits a drastic reduction of the number of viable cells at the beginning of stationary phase. The decline of cell viability was retarded by disruption of the ssnA gene, which was identified as a gene subject to RpoS-dependent negative regulation. Moreover, ssnA expression was induced at the time of decline of cell viability at early stationary phase. The viability decline was augmented in the rpoS background, and this augmentation was suppressed by ssnA mutation. Cloning of the ssnA gene in a multicopy plasmid, pBR322, caused small colony formation and slow growth in liquid medium. Cells harboring the ssnA clone showed aberrant morphology that included enlarged and filamentous shapes. The gene product was identified as a 44-kDa soluble protein, but its function could not be deduced by homology searching. From these results, we conclude that ssnA is expressed in response to a phase-specific signal(s) and that its expression level is controlled by RpoS, by a mechanism which may contribute to determination of cell number in the stationary phase.
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Affiliation(s)
- M Yamada
- Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Yamaguchi 753-8515, Japan.
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