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Vrionis HA, Wang S, Haslam B, Turner RJ. Selenite Protection of Tellurite Toxicity Toward Escherichia coli. Front Mol Biosci 2015; 2:69. [PMID: 26732755 PMCID: PMC4683179 DOI: 10.3389/fmolb.2015.00069] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 11/29/2015] [Indexed: 01/08/2023] Open
Abstract
In this work the influence of selenite on metal resistance in Escherichia coli was examined. Both synergistic and antagonistic resistance and toxicities were found upon co exposure with selenite. In wild type cells co-exposure to selenite had little effect on arsenic resistance, decreased resistance to cadmium and mercury but led to a dramatically increased resistance to tellurite of 32-fold. Due to the potential importance of thiol chemistry in metal biochemistry, deletion strains in γ-glutamylcysteine synthetase (key step in glutathione biosynthesis, encoded by gshA), thioredoxin (trxA), glutaredoxin (grxA), glutathione oxidoreductase (gor), and the periplasmic glutathione transporter (cydD) were also evaluated for resistance to various metals in the presence of selenite. The protective effect of selenite on tellurite toxicity was seen in several of the mutants and was pronounced in the gshA mutant were resistance to tellurite was increased up to 1000-fold relative to growth in the absence of selenite. Thiol oxidation studies revealed a faster rate of loss of reduced thiol content in the cell with selenite than with tellurite, indicating differential thiol reactivity. Selenite addition resulted in reactive oxygen species (ROS) production equivalent to levels associated with H2O2 addition. Tellurite addition resulted in considerably lower ROS generation while vanadate and chromate treatment did not increase ROS production above that of background. This work shows increased resistance toward most oxyanions in mutants of thiol redox suggesting that metalloid reaction with thiol components such as glutathione actually enhances toxicity of some metalloids.
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Affiliation(s)
- Helen A Vrionis
- Department of Biological Sciences, University of Calgary Calgary, AB, Canada
| | - Siyuan Wang
- Department of Biological Sciences, University of Calgary Calgary, AB, Canada
| | - Bronwyn Haslam
- Department of Biological Sciences, University of Calgary Calgary, AB, Canada
| | - Raymond J Turner
- Department of Biological Sciences, University of Calgary Calgary, AB, Canada
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Holyoake LV, Poole RK, Shepherd M. The CydDC Family of Transporters and Their Roles in Oxidase Assembly and Homeostasis. Adv Microb Physiol 2015. [PMID: 26210105 DOI: 10.1016/bs.ampbs.2015.04.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The CydDC complex of Escherichia coli is a heterodimeric ATP-binding cassette type transporter (ABC transporter) that exports the thiol-containing redox-active molecules cysteine and glutathione. These reductants are thought to aid redox homeostasis of the periplasm, permitting correct disulphide folding of periplasmic and secreted proteins. Loss of CydDC results in the periplasm becoming more oxidising and abolishes the assembly of functional bd-type respiratory oxidases that couple the oxidation of ubiquinol to the reduction of oxygen to water. In addition, CydDC-mediated redox control is important for haem ligation during cytochrome c assembly. Given the diverse roles for CydDC in redox homeostasis, respiratory metabolism and the maturation of virulence factors, this ABC transporter is an intriguing system for researchers interested in both the physiology of redox perturbations and the role of low-molecular-weight thiols during infection.
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Mota MJ, Lopes RP, Delgadillo I, Saraiva JA. Microorganisms under high pressure--adaptation, growth and biotechnological potential. Biotechnol Adv 2013; 31:1426-34. [PMID: 23831003 DOI: 10.1016/j.biotechadv.2013.06.007] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 06/21/2013] [Accepted: 06/24/2013] [Indexed: 11/16/2022]
Abstract
Hydrostatic pressure is a well-known physical parameter which is now considered an important variable of life, since organisms have the ability to adapt to pressure changes, by the development of resistance against this variable. In the past decades a huge interest in high hydrostatic pressure (HHP) technology is increasingly emerging among food and biosciences researchers. Microbial specific stress responses to HHP are currently being investigated, through the evaluation of pressure effects on biomolecules, cell structure, metabolic behavior, growth and viability. The knowledge development in this field allows a better comprehension of pressure resistance mechanisms acquired at sub-lethal pressures. In addition, new applications of HHP could arise from these studies, particularly in what concerns to biotechnology. For instance, the modulation of microbial metabolic pathways, as a response to different pressure conditions, may lead to the production of novel compounds with potential biotechnological and industrial applications. Considering pressure as an extreme life condition, this review intends to present the main findings so far reported in the scientific literature, focusing on microorganisms with the ability to withstand and to grow in high pressure conditions, whether they have innated or acquired resistance, and show the potential of the application of HHP technology for microbial biotechnology.
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Affiliation(s)
- Maria J Mota
- QOPNA, Department of Chemistry, University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal
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Hiraki T, Sekiguchi T, Kato C, Hatada Y, Maruyama T, Abe F, Konishi M. New type of pressurized cultivation method providing oxygen for piezotolerant yeast. J Biosci Bioeng 2011; 113:220-3. [PMID: 22019406 DOI: 10.1016/j.jbiosc.2011.09.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Revised: 09/21/2011] [Accepted: 09/23/2011] [Indexed: 10/16/2022]
Abstract
For efficient oxygen supply to pressurized culture, we developed a method using a highly pressurized membrane reactor with an air-saturated medium circulation system. The new method increased the cell growth of aerobic yeast approximately 20 folds larger than that in the case of using a conventional method.
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Affiliation(s)
- Toshiki Hiraki
- Institute of Biogeoscience (Biogeos), Japan Agency of Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka 237-0061, Japan
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5
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Oger PM, Jebbar M. The many ways of coping with pressure. Res Microbiol 2010; 161:799-809. [DOI: 10.1016/j.resmic.2010.09.017] [Citation(s) in RCA: 119] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Accepted: 09/09/2010] [Indexed: 12/14/2022]
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Tamegai H, Chikuma S, Ishii M, Nakasone K, Kato C. ThenarQPgenes for a two-component regulatory system from the deep-sea bacteriumShewanella violaceaDSS12. ACTA ACUST UNITED AC 2009; 19:308-12. [PMID: 17852338 DOI: 10.1080/10425170701605856] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Shewanella violacea DSS12 is facultative piezophile isolated from the deep-sea. The expression of cydDC genes (required for d-type cytochrome maturation) of the organism is regulated by hydrostatic pressure. In this study, we analyzed the nucleotide sequence upstream of cydDC in detail and found that there are putative binding sites for the NarL protein which is part of a two-component regulatory system also containing the sensor protein NarX. Furthermore, we identified the narQP genes (homologues of narXL) from S. violacea DSS12 and demonstrated the heterologous expression of narP in Escherichia coli. These results will be helpful in examining pressure regulation of gene expression in S. violacea at the molecular level.
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Affiliation(s)
- Hideyuki Tamegai
- Department of Chemistry, College of Humanities and Sciences, Nihon University, Tokyo, Japan.
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7
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Chikuma S, Kasahara R, Kato C, Tamegai H. Bacterial adaptation to high pressure: a respiratory system in the deep-sea bacteriumShewanella violaceaDSS12. FEMS Microbiol Lett 2007; 267:108-12. [PMID: 17166225 DOI: 10.1111/j.1574-6968.2006.00555.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Shewanella violacea DSS12 is a psychrophilic facultative piezophile isolated from the deep sea. In a previous study, we have shown that the bacterium adapted its respiratory components to alteration in growth pressure. This appears to be one of the bacterial adaptation mechanisms to high pressures. In this study, we measured the respiratory activities of S. violacea grown under various pressures. There was no significant difference between the cells grown under atmospheric pressure and a high pressure of 50 MPa relative to oxygen consumption of the cell-free extracts and inhibition patterns in the presence of KCN and antimycin A. Antimycin A did not inhibit the activity completely regardless of growth pressure, suggesting that there were complex III-containing and -eliminating pathways operating in parallel. On the other hand, there was a difference in the terminal oxidase activities. Our results showed that an inhibitor- and pressure-resistant terminal oxidase was expressed in the cells grown under high pressure. This property should contribute to the high-pressure adaptation mechanisms of S. violacea.
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Affiliation(s)
- Sayaka Chikuma
- Department of Chemistry, College of Humanities and Sciences, Nihon University, Tokyo, Japan
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8
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Tamegai H, Kawano H, Ishii A, Chikuma S, Nakasone K, Kato C. Pressure-regulated biosynthesis of cytochrome bd in piezo- and psychrophilic deep-sea bacterium Shewanella violacea DSS12. Extremophiles 2005; 9:247-53. [PMID: 15844013 DOI: 10.1007/s00792-005-0439-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2004] [Accepted: 02/04/2005] [Indexed: 10/25/2022]
Abstract
The genes of cytochrome bd-encoding cydAB were identified from a deep-sea bacterium Shewanella violacea DSS12. These showed significant homologies with known cydAB gene sequences from various organisms. Additionally, highly conserved regions that are important for the enzymatic function were also conserved in cydA of S. violacea. Based on the results, transcriptional analysis of cydAB operon and cydDC operon (required for assembly of cytochrome bd) of S. violacea in microaerobic condition was performed under the growth condition of various pressures. The gene of cydA was expressed even under the condition of atmospheric pressure and its expression was enhanced with pressurization. On the other hand, the expression of cydC was strongly depressed under the condition of atmospheric pressure compared with the case under high pressure. It appeared spectrophotometrically that loss of cytochrome bd in S. violacea under atmospheric pressure shown in previous study is caused mainly by the loss of cydDC. Further, under the growth condition of atmospheric pressure, either less amount or no d-type cytochrome was expressed compared with the case of high-pressure condition even if the organism was grown under alkaline condition or in the presence of uncoupler, which are the inducible condition of d-type cytochrome in Escherichia coli. These results suggested that the significant amount of d-type cytochrome expression is specific event under the growth condition of high pressure.
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Affiliation(s)
- Hideyuki Tamegai
- Department of Chemistry, College of Humanities and Sciences, Nihon University, 3-25-40 Sakurajosui, Setagaya-ku, Tokyo 156-8550, Japan.
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Kato C, Nogi Y. Correlation between phylogenetic structure and function: examples from deep-sea Shewanella. FEMS Microbiol Ecol 2001; 35:223-230. [PMID: 11311432 DOI: 10.1111/j.1574-6941.2001.tb00807.x] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The genus Shewanella is one of the typical deep-sea bacterial genera. Two isolated deep-sea Shewanella species, Shewanella benthica and Shewanella violacea, were found to be able to grow better under high hydrostatic pressure conditions than at atmospheric pressure. These species are not only piezophilic (barophilic), but also psychrophilic. Many psychrophilic and psychrotolerant Shewanella species have been isolated and characterized from cold environments, such as seawater in Antarctica or the North Sea. Some of these cold-adapted Shewanella were shown to be piezotolerant, meaning that growth occurs in a high-pressure habitat. In this review, we propose that two major sub-genus branches of the genus Shewanella should be recognized taxonomically, one group characterized as high-pressure cold-adapted species that produce substantial amounts of eicosapentaenoic acid, and the other group characterized as mesophilic pressure-sensitive species.
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Affiliation(s)
- C Kato
- The DEEPSTAR Group, Japan Marine Science and Technology Center, 2-15 Natsushima-cho, 237-0061, Yokosuka, Japan
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10
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Abstract
Microorganisms that prefer high-pressure conditions are termed piezophiles (previously termed barophiles). The molecular basis of piezophily is now being investigated extensively focusing on aspects of gene regulation and the function of certain proteins in deep-sea isolates. Little attention has been paid, however, to the potential biotechnological applications of piezophiles compared with other extremophiles. Based on the fundamental knowledge available, we will try to answer the following questions: How can we exploit the biotechnological potential of piezophiles? What can be understood by the application of high-pressure in biological systems?
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Affiliation(s)
- F Abe
- The DEEPSTAR Group, Japan Marine Science and Technology Center (JAMSTEC), 2-15 Natsushima-cho, 237-0061, Yokosuka, Japan.
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11
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Poole RK, Cook GM. Redundancy of aerobic respiratory chains in bacteria? Routes, reasons and regulation. Adv Microb Physiol 2001; 43:165-224. [PMID: 10907557 DOI: 10.1016/s0065-2911(00)43005-5] [Citation(s) in RCA: 185] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Bacteria are the most remarkable organisms in the biosphere, surviving and growing in environments that support no other life forms. Underlying this ability is a flexible metabolism controlled by a multitude of environmental sensors and regulators of gene expression. It is not surprising, therefore, that bacterial respiration is complex and highly adaptable: virtually all bacteria have multiple, branched pathways for electron transfer from numerous low-potential reductants to several terminal electron acceptors. Such pathways, particularly those involved in anaerobic respiration, may involve periplasmic components, but the respiratory apparatus is largely membrane-bound and organized such that electron flow is coupled to proton (or sodium ion) transport, generating a protonmotive force. It has long been supposed that the multiplicity of pathways serves to provide flexibility in the face of environmental stresses, but the existence of apparently redundant pathways for electrons to a single acceptor, say dioxygen, is harder to explain. Clues have come from studying the expression of oxidases in response to growth conditions, the phenotypes of mutants lacking one or more oxidases, and biochemical characterization of individual oxidases. Terminal oxidases that share the essential properties of substrate (cytochrome c or quinol) oxidation, dioxygen reduction and, in some cases, proton translocation, differ in subunit architecture and complement of redox centres. Perhaps more significantly, they differ in their affinities for oxidant and reductant, mode of regulation, and inhibitor sensitivity; these differences to some extent rationalize the presence of multiple oxidases. However, intriguing requirements for particular functions in certain physiological functions remain unexplained. For example, a large body of evidence demonstrates that cytochrome bd is essential for growth and survival under certain conditions. In this review, the physiological basis of the many phenotypes of Cyd-mutants is explored, particularly the requirement for this oxidase in diazotrophy, growth at low protonmotive force, survival in the stationary phase, and resistance to oxidative stress and Fe(III) chelators.
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Affiliation(s)
- R K Poole
- Krebs Institute for Biomolecular Research, University of Sheffield, UK
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12
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Abstract
SUMMARY
Profound changes are occurring in the strategies that biotechnology-based industries are deploying in the search for exploitable biology and to discover new products and develop new or improved processes. The advances that have been made in the past decade in areas such as combinatorial chemistry, combinatorial biosynthesis, metabolic pathway engineering, gene shuffling, and directed evolution of proteins have caused some companies to consider withdrawing from natural product screening. In this review we examine the paradigm shift from traditional biology to bioinformatics that is revolutionizing exploitable biology. We conclude that the reinvigorated means of detecting novel organisms, novel chemical structures, and novel biocatalytic activities will ensure that natural products will continue to be a primary resource for biotechnology. The paradigm shift has been driven by a convergence of complementary technologies, exemplified by DNA sequencing and amplification, genome sequencing and annotation, proteome analysis, and phenotypic inventorying, resulting in the establishment of huge databases that can be mined in order to generate useful knowledge such as the identity and characterization of organisms and the identity of biotechnology targets. Concurrently there have been major advances in understanding the extent of microbial diversity, how uncultured organisms might be grown, and how expression of the metabolic potential of microorganisms can be maximized. The integration of information from complementary databases presents a significant challenge. Such integration should facilitate answers to complex questions involving sequence, biochemical, physiological, taxonomic, and ecological information of the sort posed in exploitable biology. The paradigm shift which we discuss is not absolute in the sense that it will replace established microbiology; rather, it reinforces our view that innovative microbiology is essential for releasing the potential of microbial diversity for biotechnology penetration throughout industry. Various of these issues are considered with reference to deep-sea microbiology and biotechnology.
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13
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Bull AT, Ward AC, Goodfellow M. Search and discovery strategies for biotechnology: the paradigm shift. Microbiol Mol Biol Rev 2000; 64:573-606. [PMID: 10974127 PMCID: PMC99005 DOI: 10.1128/mmbr.64.3.573-606.2000] [Citation(s) in RCA: 300] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Profound changes are occurring in the strategies that biotechnology-based industries are deploying in the search for exploitable biology and to discover new products and develop new or improved processes. The advances that have been made in the past decade in areas such as combinatorial chemistry, combinatorial biosynthesis, metabolic pathway engineering, gene shuffling, and directed evolution of proteins have caused some companies to consider withdrawing from natural product screening. In this review we examine the paradigm shift from traditional biology to bioinformatics that is revolutionizing exploitable biology. We conclude that the reinvigorated means of detecting novel organisms, novel chemical structures, and novel biocatalytic activities will ensure that natural products will continue to be a primary resource for biotechnology. The paradigm shift has been driven by a convergence of complementary technologies, exemplified by DNA sequencing and amplification, genome sequencing and annotation, proteome analysis, and phenotypic inventorying, resulting in the establishment of huge databases that can be mined in order to generate useful knowledge such as the identity and characterization of organisms and the identity of biotechnology targets. Concurrently there have been major advances in understanding the extent of microbial diversity, how uncultured organisms might be grown, and how expression of the metabolic potential of microorganisms can be maximized. The integration of information from complementary databases presents a significant challenge. Such integration should facilitate answers to complex questions involving sequence, biochemical, physiological, taxonomic, and ecological information of the sort posed in exploitable biology. The paradigm shift which we discuss is not absolute in the sense that it will replace established microbiology; rather, it reinforces our view that innovative microbiology is essential for releasing the potential of microbial diversity for biotechnology penetration throughout industry. Various of these issues are considered with reference to deep-sea microbiology and biotechnology.
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Affiliation(s)
- A T Bull
- Research School of Biosciences, University of Kent, Canterbury, Kent CT2 7NJ, United Kingdom.
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Yamada M, Nakasone K, Tamegai H, Kato C, Usami R, Horikoshi K. Pressure regulation of soluble cytochromes c in a deep-Sea piezophilic bacterium, Shewanella violacea. J Bacteriol 2000; 182:2945-52. [PMID: 10781566 PMCID: PMC102006 DOI: 10.1128/jb.182.10.2945-2952.2000] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Two c-type cytochromes from the soluble fraction of a deep-sea moderately piezophilic bacterium, Shewanella violacea, were purified and characterized, and the genes coding for these cytochromes were cloned and sequenced. One of the cytochromes, designated cytochrome c(A), was found to have a molecular mass of approximately 8.3 kDa, and it contained one heme c per molecule. The other, designated cytochrome c(B), was found to have a molecular mass of approximately 23 kDa, and it contained two heme c molecules per protein molecule. The amount of cytochrome c(B) expressed in cells grown at high hydrostatic pressure (50 MPa) was less than that in cells grown at atmospheric pressure, whereas cytochrome c(A) was constitutively expressed under all pressure conditions examined. The results of Northern blotting analysis were consistent with the above-mentioned observations and suggested that the pressure regulation of cytochrome c(B) gene expression occurred at the transcriptional level. These results suggest that the components of the respiratory chain of moderately piezophilic S. violacea could be exchanged according to the growth pressure conditions.
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Affiliation(s)
- M Yamada
- The DEEPSTAR Group, Japan Marine Science and Technology Center, Yokosuka 237-0061, Japan
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15
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Allen EE, Bartlett DH. FabF is required for piezoregulation of cis-vaccenic acid levels and piezophilic growth of the deep-Sea bacterium Photobacterium profundum strain SS9. J Bacteriol 2000; 182:1264-71. [PMID: 10671446 PMCID: PMC94411 DOI: 10.1128/jb.182.5.1264-1271.2000] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To more fully explore the role of unsaturated fatty acids in high-pressure, low-temperature growth, the fabF gene from the psychrotolerant, piezophilic deep-sea bacterium Photobacterium profundum strain SS9 was characterized and its role and regulation were examined. An SS9 strain harboring a disruption in the fabF gene (strain EA40) displayed growth impairment at elevated hydrostatic pressure concomitant with diminished cis-vaccenic acid (18:1) production. However, growth ability at elevated pressure could be restored to wild-type levels by the addition of exogenous 18:1 to the growth medium. Transcript analysis did not indicate that the SS9 fabF gene is transcriptionally regulated, suggesting that the elevated 18:1 levels produced in response to pressure increase result from posttranscriptional changes. Unlike many pressure-adapted bacterial species such as SS9, the mesophile Escherichia coli did not regulate its fatty acid composition in an adaptive manner in response to changes in hydrostatic pressure. Moreover, an E. coli fabF strain was as susceptible to elevated pressure as wild-type cells. It is proposed that the SS9 fabF product, beta-ketoacyl-acyl carrier protein synthase II has evolved novel pressure-responsive characteristics which facilitate SS9 growth at high pressure.
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Affiliation(s)
- E E Allen
- Center for Marine Biotechnology and Biomedicine, Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California 92093-0202, USA
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How do Deep-Sea Microorganisms Respond to Changes in Environmental Pressure? ACTA ACUST UNITED AC 2000. [DOI: 10.1016/s1568-1254(00)80021-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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17
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Abstract
There has been a renewal of interest in the survival strategies employed by deep-sea, high-pressure-adapted (piezophilic) microorganisms as well as in the effects of high pressure on mesophilic, 1-atmosphere-pressure-adapted microorganisms. This is partly the result of a greater appreciation of the adaptations of microorganisms to life in extreme environments and partly the result of the development of new techniques for examining physiological and molecular processes as a function of pressure.
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Affiliation(s)
- F Abe
- DEEPSTAR Group, Japan Marine Science and Technology Center (JAMSTEC), 2-15 Natsushima-cho, Yokosuka 237-0061, Japan.
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18
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Abstract
The deep-sea environment is characterized by high pressure and low temperature but in the vicinity of hydrothermal vents regions of extremely high temperature exist. Deep-sea microorganisms have specially adapted features that enable them to live and grow in this extreme environment. Recent research on the physiology and molecular biology of deep-sea barophilic bacteria has identified pressure-regulated operons and shown that microbial growth is influenced by the relationship between temperature and pressure in the deep-sea environment.
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Affiliation(s)
- K Horikoshi
- The DEEPSTAR group, Japan Marine Science and Technology Center, (JAMSTEC) 2-15 Natsushima-cho, Yokosuka 237-0061, Japan.
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19
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Welch TJ, Bartlett DH. Identification of a regulatory protein required for pressure-responsive gene expression in the deep-sea bacterium Photobacterium species strain SS9. Mol Microbiol 1998; 27:977-85. [PMID: 9535087 DOI: 10.1046/j.1365-2958.1998.00742.x] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Here, we report the characterization of a gene necessary for hydrostatic pressure regulation of gene expression in the deep-sea bacterium Photobacterium species strain SS9. The deduced amino acid sequence of the gene product shares extensive similarity to ToxR, a transmembrane DNA-binding protein first discovered as a virulence determinant in the pathogenic bacterium Vibrio cholerae. Changes in hydrostatic pressure induce changes in both the abundance and the activity of the SS9 ToxR protein (or the activity of a ToxR-regulated protein). As with other high-pressure-inducible phenomena observed in higher organisms, anaesthetics antagonize high-pressure signalling mediated by ToxR. It is suggested that SS9 ToxR has evolved the ability to respond to pressure-mediated alterations in membrane structure. V. cholerae and SS9 also share similarity in a ToxR-regulated protein, indicating that part of the ToxR regulon is conserved in diverse members of the family Vibrionaceae. The SS9 ToxR system represents a useful model for studies of signal transduction and environmental adaptation in the largest portion of the biosphere, the deep sea.
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Affiliation(s)
- T J Welch
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla 92093-0202, USA
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20
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Li L, Kato C, Nogi Y, Horikoshi K. Distribution of the pressure-regulated operons in deep-sea bacteria. FEMS Microbiol Lett 1998; 159:159-66. [PMID: 9503608 DOI: 10.1111/j.1574-6968.1998.tb12855.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
DNA regions corresponding to portions of two different pressure-regulated operons previously identified in two deep-sea barophilic bacteria were separately PCR amplified from a variety of deep-sea microorganisms and sequenced. With the two sets of primers employed, amplification was particularly successful from the more barophilic bacteria examined. 16S rRNA sequence analysis revealed that these bacteria are all phylogenetically related and belong in a sub-branch of the genus Shewanella containing only the deep-sea Shewanella barophilic bacteria. We define this sub-branch as the 'Shewanella barophile branch' containing at least two different species. Our results suggest that the DNA sequences of the pressure-regulated operons can be regarded as marker sequences to identify the Shewanella barophilic strains.
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Affiliation(s)
- L Li
- DEEPSTAR Group, Japan Marine and Science and Technology Center (JAMSTEC), Yokosuka, Japan.
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