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Wang W, Liu J, Mishra B, Mukhtar MS, McDowell JM. Sparking a sulfur war between plants and pathogens. TRENDS IN PLANT SCIENCE 2022; 27:1253-1265. [PMID: 36028431 DOI: 10.1016/j.tplants.2022.07.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 07/03/2022] [Accepted: 07/21/2022] [Indexed: 06/15/2023]
Abstract
The biochemical versatility of sulfur (S) lends itself to myriad roles in plant-pathogen interactions. This review evaluates the current understanding of mechanisms by which pathogens acquire S from their plant hosts and highlights new evidence that plants can limit S availability during the immune responses. We discuss the discovery of host disease-susceptibility genes related to S that can be genetically manipulated to create new crop resistance. Finally, we summarize future research challenges and propose a research agenda that leverages systems biology approaches for a holistic understanding of this important element's diverse roles in plant disease resistance and susceptibility.
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Affiliation(s)
- Wei Wang
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA 24061, USA
| | - Jinbao Liu
- Department of Biology, University of Alabama-Birmingham, Birmingham, AL 35294, USA
| | - Bharat Mishra
- Department of Biology, University of Alabama-Birmingham, Birmingham, AL 35294, USA
| | - M Shahid Mukhtar
- Department of Biology, University of Alabama-Birmingham, Birmingham, AL 35294, USA
| | - John M McDowell
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA 24061, USA.
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Narayan OP, Verma N, Jogawat A, Dua M, Johri AK. Sulfur transfer from the endophytic fungus Serendipita indica improves maize growth and requires the sulfate transporter SiSulT. THE PLANT CELL 2021; 33:1268-1285. [PMID: 33793849 DOI: 10.1093/plcell/koab006] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 12/16/2020] [Indexed: 06/12/2023]
Abstract
A deficiency of the essential macronutrient sulfur leads to stunted plant growth and yield loss; however, an association with a symbiotic fungus can greatly improve nutrient uptake by the host plant. Here, we identified and functionally characterized a high-affinity sulfate transporter from the endophytic fungus Serendipita indica. SiSulT fulfills all the criteria expected of a functional sulfate transporter responding to sulfur limitation: SiSulT expression was induced when S. indica was grown under low-sulfate conditions, and heterologous expression of SiSulT complemented a yeast mutant lacking sulfate transport. We generated a knockdown strain of SiSulT by RNA interference to investigate the consequences of the partial loss of this transporter for the fungus and the host plant (maize, Zea mays) during colonization. Wild-type (WT) S. indica, but not the knockdown strain (kd-SiSulT), largely compensated for low-sulfate availability and supported plant growth. Colonization by WT S. indica also allowed maize roots to allocate precious resources away from sulfate assimilation under low-sulfur conditions, as evidenced by the reduction in expression of most sulfate assimilation genes. Our study illustrates the utility of the endophyte S. indica in sulfur nutrition research and offers potential avenues for agronomically sound amelioration of plant growth in low-sulfate environments.
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Affiliation(s)
- Om Prakash Narayan
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Nidhi Verma
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Abhimanyu Jogawat
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Meenakshi Dua
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Atul Kumar Johri
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
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Adekanmbi AO, Adelowo OO, Okoh AI, Fagade OE. Metal-resistance encoding gene-fingerprints in some bacteria isolated from wastewaters of selected printeries in Ibadan, South-western Nigeria. JOURNAL OF TAIBAH UNIVERSITY FOR SCIENCE 2019. [DOI: 10.1080/16583655.2018.1561968] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Abimbola O. Adekanmbi
- Environmental Microbiology and Biotechnology Laboratory, Department of Microbiology, University of Ibadan, Ibadan, Nigeria
- Applied and Environmental Microbiology Research Group (AEMREG), Department of Biochemistry and Microbiology, University of Fort Hare, Alice, South Africa
- SAMRC Microbial Water Quality Monitoring Centre, University of Fort Hare, Alice, South Africa
| | - Olawale O. Adelowo
- Environmental Microbiology and Biotechnology Laboratory, Department of Microbiology, University of Ibadan, Ibadan, Nigeria
| | - Anthony I. Okoh
- Applied and Environmental Microbiology Research Group (AEMREG), Department of Biochemistry and Microbiology, University of Fort Hare, Alice, South Africa
- SAMRC Microbial Water Quality Monitoring Centre, University of Fort Hare, Alice, South Africa
| | - Obasola E. Fagade
- Environmental Microbiology and Biotechnology Laboratory, Department of Microbiology, University of Ibadan, Ibadan, Nigeria
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Franco LC, Steinbeisser S, Zane GM, Wall JD, Fields MW. Cr(VI) reduction and physiological toxicity are impacted by resource ratio in Desulfovibrio vulgaris. Appl Microbiol Biotechnol 2018; 102:2839-2850. [PMID: 29429007 PMCID: PMC5847207 DOI: 10.1007/s00253-017-8724-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 12/11/2017] [Accepted: 12/18/2017] [Indexed: 11/30/2022]
Abstract
Desulfovibrio spp. are capable of heavy metal reduction and are well-studied systems for understanding metal fate and transport in anaerobic environments. Desulfovibrio vulgaris Hildenborough was grown under environmentally relevant conditions (i.e., temperature, nutrient limitation) to elucidate the impacts on Cr(VI) reduction on cellular physiology. Growth at 20 °C was slower than 30 °C and the presence of 50 μM Cr(VI) caused extended lag times for all conditions, but once growth resumed the growth rate was similar to that without Cr(VI). Cr(VI) reduction rates were greatly diminished at 20 °C for both 50 and 100 μM Cr(VI), particularly for the electron acceptor limited (EAL) condition in which Cr(VI) reduction was much slower, the growth lag much longer (200 h), and viability decreased compared to balanced (BAL) and electron donor limited (EDL) conditions. When sulfate levels were increased in the presence of Cr(VI), cellular responses improved via a shorter lag time to growth. Similar results were observed between the different resource (donor/acceptor) ratio conditions when the sulfate levels were normalized (10 mM), and these results indicated that resource ratio (donor/acceptor) impacted D. vulgaris response to Cr(VI) and not merely sulfate limitation. The results suggest that temperature and resource ratios greatly impacted the extent of Cr(VI) toxicity, Cr(VI) reduction, and the subsequent cellular health via Cr(VI) influx and overall metabolic rate. The results also emphasized the need to perform experiments at lower temperatures with nutrient limitation to make accurate predictions of heavy metal reduction rates as well as physiological states in the environment.
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Affiliation(s)
- Lauren C Franco
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT, USA.,Center for Biofilm Engineering, Montana State University, 366 Barnard Hall, Bozeman, MT, 59717, USA
| | - Sadie Steinbeisser
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT, USA.,Center for Biofilm Engineering, Montana State University, 366 Barnard Hall, Bozeman, MT, 59717, USA
| | - Grant M Zane
- Departments of Biochemistry and Molecular Microbiology and Immunology, University of Missouri-Columbia, Columbia, MO, USA
| | - Judy D Wall
- Departments of Biochemistry and Molecular Microbiology and Immunology, University of Missouri-Columbia, Columbia, MO, USA.,ENIGMA, Berkeley, CA, USA
| | - Matthew W Fields
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT, USA. .,Center for Biofilm Engineering, Montana State University, 366 Barnard Hall, Bozeman, MT, 59717, USA. .,ENIGMA, Berkeley, CA, USA, .
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Aguilar-Barajas E, Díaz-Pérez C, Ramírez-Díaz MI, Riveros-Rosas H, Cervantes C. Bacterial transport of sulfate, molybdate, and related oxyanions. Biometals 2011; 24:687-707. [PMID: 21301930 DOI: 10.1007/s10534-011-9421-x] [Citation(s) in RCA: 130] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Accepted: 01/26/2011] [Indexed: 12/29/2022]
Affiliation(s)
- Esther Aguilar-Barajas
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana, Edificio B-3, Ciudad Universitaria, 58030 Morelia, Michoacan, Mexico
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Verma T, Garg S, Ramteke P. Genetic correlation between chromium resistance and reduction inBacillus brevisisolated from tannery effluent. J Appl Microbiol 2009; 107:1425-32. [DOI: 10.1111/j.1365-2672.2009.04326.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Pereira Y, Lagniel G, Godat E, Baudouin-Cornu P, Junot C, Labarre J. Chromate causes sulfur starvation in yeast. Toxicol Sci 2008; 106:400-12. [PMID: 18794233 DOI: 10.1093/toxsci/kfn193] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Chromate is a widespread pollutant as a waste of human activities. However, the mechanisms underlying its high toxicity are not clearly understood. In this work, we used the yeast Saccharomyces cerevisiae to analyse the physiological effects of chromate exposure in a eukaryote cell model. We show that chromate causes a strong decrease of sulfate assimilation and sulfur metabolite pools suggesting that cells experience sulfur starvation. As a consequence, nearly all enzymes of the sulfur pathway are highly induced as well as enzymes of the sulfur-sparing response such as Pdc6, the sulfur-poor pyruvate decarboxylase. The induction of Pdc6 was regulated at the mRNA level and dependent upon Met32, a coactivator of Met4, the transcriptional activator of the sulfur pathway. Finally, we found that chromate enters the cells mainly through sulfate transporters and competitively inhibits sulfate uptake. Also consistent with a competition between the two substrates, sulfate supplementation relieves chromate toxicity. However, the data suggest that the chromate-mediated sulfur depletion is not simply due to this competitive uptake but would also be the consequence of competitive metabolism between the two compounds presumably at another step of the sulfur assimilation pathway.
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Affiliation(s)
- Yannick Pereira
- Laboratoire de Biologie Intégrative, SBIGeM/iBiTec-S, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex, France
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Distribution and Evolution of Pseudogenes, Gene Losses, and a Gene Rearrangement in the Plastid Genome of the Nonphotosynthetic Liverwort, Aneura mirabilis (Metzgeriales, Jungermanniopsida). J Mol Evol 2008; 67:111-22. [DOI: 10.1007/s00239-008-9133-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2008] [Revised: 05/28/2008] [Accepted: 06/09/2008] [Indexed: 10/21/2022]
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Kredich NM, Hulanicka MD, Hallquist SG. Synthesis of L-cysteine in Salmonella typhimurium. CIBA FOUNDATION SYMPOSIUM 2008:87-99. [PMID: 398768 DOI: 10.1002/9780470720554.ch6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
In Salmonella typhimurium and Escherichia coli the biosynthesis of L-cysteine from L-serine and inorganic sulphate proceeds along a branched convergent pathway along one arm of which sulphate is reduced to sulphide, while on the other L-serine is acetylated to O-acetyl-L-serine. This system is subject to positive genetic control in which growth on a poor sulphur source, O-acetyl-L-serine and the product of the cysB regulatory gene are all required for derepression. The final step consists of the formation of L-cysteine from O-acetyl-L-serine and sulphide. We find that in S. typhimurium this reaction is catalysed by two different enzymes, O-acetylserine sulphydrylase A and O-acetylserine sulphydrylase B, coded for by cysK and cysM respectively. Both enzymes are under the control of the cysteine regulon, and either alone is sufficient for cysteine prototrophy during aerobic growth. Although the advantage to the bacterium of having two separate enzymes to carry out the same reaction is unclear, preliminary data suggest that O-acetylserine sulphydrylase B is preferentially utilized for cysteine biosynthesis during anaerobic growth. We speculate that one enzyme may prefer free sulphide as a substrate while the other may use a bound form of sulphide.
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Delgado MJ, Tresierra-Ayala A, Talbi C, Bedmar EJ. Functional characterization of the Bradyrhizobium japonicum modA and modB genes involved in molybdenum transport. MICROBIOLOGY (READING, ENGLAND) 2006; 152:199-207. [PMID: 16385130 DOI: 10.1099/mic.0.28347-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A modABC gene cluster that encodes an ABC-type, high-affinity molybdate transporter from Bradyrhizobium japonicum has been isolated and characterized. B. japonicum modA and modB mutant strains were unable to grow aerobically or anaerobically with nitrate as nitrogen source or as respiratory substrate, respectively, and lacked nitrate reductase activity. The nitrogen-fixing ability of the mod mutants in symbiotic association with soybean plants grown in a Mo-deficient mineral solution was severely impaired. Addition of molybdate to the bacterial growth medium or to the plant mineral solution fully restored the wild-type phenotype. Because the amount of molybdate required for suppression of the mutant phenotype either under free-living or under symbiotic conditions was dependent on sulphate concentration, it is likely that a sulphate transporter is also involved in Mo uptake in B. japonicum. The promoter region of the modABC genes has been characterized by primer extension. Reverse transcription and expression of a transcriptional fusion, P(modA)-lacZ, was detected only in a B. japonicum modA mutant grown in a medium without molybdate supplementation. These findings indicate that transcription of the B. japonicum modABC genes is repressed by molybdate.
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Affiliation(s)
- María J Delgado
- Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, CSIC, PO Box 419, 18080 Granada, Spain
| | - Alvaro Tresierra-Ayala
- Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, CSIC, PO Box 419, 18080 Granada, Spain
| | - Chouhra Talbi
- Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, CSIC, PO Box 419, 18080 Granada, Spain
| | - Eulogio J Bedmar
- Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, CSIC, PO Box 419, 18080 Granada, Spain
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Fulladosa E, Murat JC, Villaescusa I. Effect of cadmium(II), chromium(VI), and arsenic(V) on long-term viability- and growth-inhibition assays using Vibrio fischeri marine bacteria. ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2005; 49:299-306. [PMID: 16132421 DOI: 10.1007/s00244-004-0170-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2004] [Accepted: 03/20/2005] [Indexed: 05/04/2023]
Abstract
As a complement to previous results obtained using the standard Microtox acute-toxicity test, which is based on measuring the rapid decrease of bioluminescence (5 to 30 minutes of exposure) in Vibrio fischeri bacteria in the presence of toxicants, the long-term effects of Cd(II), Cr(VI), and As(V) were studied on growth rate and viability assays of the same bacteria adapted to longer-lasting cultures, i.e., 48 or 72 hours instead of 5 or 30 minutes. Effects on viability or growth, as studied by establishing dose- and time-response curves, confirmed that these poisonous chemicals were not particularly toxic to these bacteria. Nevertheless, in the case of Cr(VI), the viability-inhibition assay appeared to be more sensitive than the Microtox acute-toxicity test. Interestingly, it was possible to observe a clear hormesis phenomenon, especially for Cd(II), under the conditions of both viability- and growth-inhibition assays.
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Affiliation(s)
- E Fulladosa
- Department of Chemical Engineering, University of Girona, Avda. Lluís Santaló, s/n, Girona, 17071, Spain
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Encheva V, Wait R, Gharbia SE, Begum S, Shah HN. Proteome analysis of serovars Typhimurium and Pullorum of Salmonella enterica subspecies I. BMC Microbiol 2005; 5:42. [PMID: 16026608 PMCID: PMC1181816 DOI: 10.1186/1471-2180-5-42] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2005] [Accepted: 07/18/2005] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND Salmonella enterica subspecies I includes several closely related serovars which differ in host ranges and ability to cause disease. The basis for the diversity in host range and pathogenic potential of the serovars is not well understood, and it is not known how host-restricted variants appeared and what factors were lost or acquired during adaptations to a specific environment. Differences apparent from the genomic data do not necessarily correspond to functional proteins and more importantly differential regulation of otherwise identical gene content may play a role in the diverse phenotypes of the serovars of Salmonella. RESULTS In this study a comparative analysis of the cytosolic proteins of serovars Typhimurium and Pullorum was performed using two-dimensional gel electrophoresis and the proteins of interest were identified using mass spectrometry. An annotated reference map was created for serovar Typhimurium containing 233 entries, which included many metabolic enzymes, ribosomal proteins, chaperones and many other proteins characteristic for the growing cell. The comparative analysis of the two serovars revealed a high degree of variation amongst isolates obtained from different sources and, in some cases, the variation was greater between isolates of the same serovar than between isolates with different sero-specificity. However, several serovar-specific proteins, including intermediates in sulphate utilisation and cysteine synthesis, were also found despite the fact that the genes encoding those proteins are present in the genomes of both serovars. CONCLUSION Current microbial proteomics are generally based on the use of a single reference or type strain of a species. This study has shown the importance of incorporating a large number of strains of a species, as the diversity of the proteome in the microbial population appears to be significantly greater than expected. The characterisation of a diverse selection of strains revealed parts of the proteome of S. enterica that alter their expression while others remain stable and allowed for the identification of serovar-specific factors that have so far remained undetected by other methods.
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Affiliation(s)
- Vesela Encheva
- Molecular Identification Services Unit, NCTC, Centre for Infections, Health Protection Agency, London, UK
| | - Robin Wait
- Kennedy Institute of Rheumatology Division, Faculty of Medicine, Imperial College London, UK
| | - Saheer E Gharbia
- Genomics Proteomics and Bioinformatics Unit, Centre for Infection, Health Protection Agency, London, UK
| | - Shajna Begum
- Kennedy Institute of Rheumatology Division, Faculty of Medicine, Imperial College London, UK
| | - Haroun N Shah
- Molecular Identification Services Unit, NCTC, Centre for Infections, Health Protection Agency, London, UK
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Shrestha S, Salins LLE, Mark Ensor C, Daunert S. Rationally designed fluorescently labeled sulfate-binding protein mutants: evaluation in the development of a sensing system for sulfate. Biotechnol Bioeng 2002; 78:517-26. [PMID: 12115121 DOI: 10.1002/bit.10221] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Periplasmic binding proteins from E. coli undergo large conformational changes upon binding their respective ligands. By attaching a fluorescent probe at rationally selected unique sites on the protein, these conformational changes in the protein can be monitored by measuring the changes in fluorescence intensity of the probe which allow the development of reagentless sensing systems for their corresponding ligands. In this work, we evaluated several sites on bacterial periplasmic sulfate-binding protein (SBP) for attachment of a fluorescent probe and rationally designed a reagentless sensing system for sulfate. Eight different mutants of SBP were prepared by employing the polymerase chain reaction (PCR) to introduce a unique cysteine residue at a specific location on the protein. The sites Gly55, Ser90, Ser129, Ala140, Leu145, Ser171, Val181, and Gly186 were chosen for mutagenesis by studying the three-dimensional X-ray crystal structure of SBP. An environment-sensitive fluorescent probe (MDCC) was then attached site-specifically to the protein through the sulfhydryl group of the unique cysteine residue introduced. Each fluorescent probe-conjugated SBP mutant was characterized in terms of its fluorescence properties and Ser171 was determined to be the best site for the attachment of the fluorescent probe that would allow for the development of a reagentless sensing system for sulfate. Three different environment-sensitive fluorescent probes (1,5-IAEDANS, MDCC, and acylodan) were studied with the SBP171 mutant protein. A calibration curve for sulfate was constructed using the labeled protein and relating the change in the fluorescence intensity with the amount of sulfate present in the sample. The detection limit for sulfate was found to be in the submicromolar range using this system. The selectivity of the sensing system was demonstrated by evaluating its response to other anions. A fast and selective sensing system with detection limits for sulfate in the submicromolar range was developed.
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Affiliation(s)
- Suresh Shrestha
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055, USA
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Wooff E, Michell SLI, Gordon SV, Chambers MA, Bardarov S, Jacobs WR, Hewinson RG, Wheeler PR. Functional genomics reveals the sole sulphate transporter of the Mycobacterium tuberculosis complex and its relevance to the acquisition of sulphur in vivo. Mol Microbiol 2002; 43:653-63. [PMID: 11929522 DOI: 10.1046/j.1365-2958.2002.02771.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Sulphur is essential for some of the most vital biological activities such as translation initiation and redox maintenance, and genes involved in sulphur metabolism have been implicated in virulence. Mycobacterium tuberculosis has three predicted genes for the prototrophic acquisition of sulphur as sulphate: cysA, part of an ABC transporter, and cysA2 and A3, SseC sulphotransferases. Screening for amino acid auxotrophs of Mycobacterium bovis BCG, obtained by transposon mutagenesis, was used to select methionine auxotrophs requiring a sulphur-containing amino acid for growth. We have characterized one of these auxotrophs as being disrupted in cysA. Both the cysA mutant and a previously identified mutant in an upstream gene, subI, were functionally characterized as being completely unable to take up sulphate. Complementation of the cysA mutant with the wild-type gene from M. tuberculosis restored prototrophy and the ability to take up sulphate with the functional characteristics of an ABC transporter. Hence, it appears that this is the sole locus encoding inorganic sulphur transport in the M. tuberculosis complex.
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Affiliation(s)
- Esen Wooff
- Tuberculosis Research Group, Veterinary Laboratories Agency-Weybridge, New Haw, Surrey, UK
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Rosentel JK, Healy F, Maupin-Furlow JA, Lee JH, Shanmugam KT. Molybdate and regulation of mod (molybdate transport), fdhF, and hyc (formate hydrogenlyase) operons in Escherichia coli. J Bacteriol 1995; 177:4857-64. [PMID: 7665461 PMCID: PMC177258 DOI: 10.1128/jb.177.17.4857-4864.1995] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Escherichia coli mutants with defined mutations in specific mod genes that affect molybdate transport were isolated and analyzed for the effects of particular mutations on the regulation of the mod operon as well as the fdhF and hyc operons which code for the components of the formate hydrogenlyase (FHL) complex. phi (hyc'-'lacZ+) mod double mutants produced beta-galactosidase activity only when they were cultured in medium supplemented with molybdate. This requirement was specific for molybdate and was independent of the moa, mob, and moe gene products needed for molybdopterin guanine dinucleotide (MGD) synthesis, as well as Mog protein. The concentration of molybdate required for FHL production by mod mutants was dependent on medium composition. In low-sulfur medium, the amount of molybdate needed by mod mutants for the production of half-maximal FHL activity was increased approximately 20 times by the addition of 40 mM of sulfate, mod mutants growing in low-sulfur medium transported molybdate through the sulfate transport system, as seen by the requirement of the cysA gene product for this transport. In wild-type E. coli, the mod operon is expressed at very low levels, and a mod+ merodiploid E. coli carrying a modA-lacZ fusion produced less than 20 units of beta-galactosidase activity. This level was increased by over 175 times by a mutation in the modA, modB, or modC gene. The addition of molybdate to the growth medium of a mod mutant lowered phi (modA'-'lacZ+) expression. Repression of the mod operon was sensitive to molybdate but was insensitive to mutations in the MGD synthetic pathway. These physiological and genetic experiments show that molybdate can be transported by one of the following three anion transport system in E. coli: the native system, the sulfate transport system (cysTWA gene products), and an undefined transporter. Upon entering the cytoplasm, molybdate branches out to mod regulation, fdhF and hyc activation, and metabolic conversion, leading to MGD synthesis and active molybdoenzyme synthesis.
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Affiliation(s)
- J K Rosentel
- Department of Microbiology and Cell Science, University of Florida, Gainesville 32611, USA
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Sirko A, Zatyka M, Sadowy E, Hulanicka D. Sulfate and thiosulfate transport in Escherichia coli K-12: evidence for a functional overlapping of sulfate- and thiosulfate-binding proteins. J Bacteriol 1995; 177:4134-6. [PMID: 7608089 PMCID: PMC177147 DOI: 10.1128/jb.177.14.4134-4136.1995] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
In Escherichia coli, sulfate and thiosulfate ions are transported by an ABC-type transporter consisting of both the membrane components (the products of cysT, cysW, and cysA genes) and the periplasmic binders (the products of cysP and sbp genes). The single cysP and sbp mutants are able to utilize both sulfate and thiosulfate as a sole sulfur source, while the inactivation of both genes leads to cysteine auxotrophy resulting from the block in the transport of both ions.
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Affiliation(s)
- A Sirko
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw
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Abstract
A comparative study has been made on the mechanisms of toxicities of trivalent and hexavalent forms of chromium in Neurospora crassa. Of the two forms, Cr6+ is more toxic than Cr3+. The toxicity of Cr3+ was found to be due to its specific antagonism with iron uptake. Fe3+ was found to be very effective in reversing the toxicity of Cr3+ by concomitantly suppressing its uptake. That the Cr3+ toxicity caused a conditional intracellular iron deficiency was indicated by the decrease in the activities of catalase and uricase and a progressive increase in the excretion of iron binding compound into the medium. The toxicity of Cr6+ (as Cr2O7(2-)) was found to be due to its specific antagonism of sulfate uptake. Methionine was found to be more effective in reversing dichromate toxicity than sulfate, probably by repressing the synthesis of sulfate permeases responsible for dichromate (Cr6+) uptake. Maximal uptake of Cr6+ was nearly tenfold lower and Vmax much higher than that of Cr3+. Evidence has been adduced to show that Cr6+ and Cr3+ were toxic by themselves and that interconversion between the tri- and hexavalent forms of chromium did not occur to any detectable extent.
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Affiliation(s)
- V V Ramana
- Department of Biochemistry, Osmania University, Hydrabad, India
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19
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Abstract
Siroheme, a cofactor of both sulfite and nitrite reductase in Salmonella typhimurium, requires the cysG gene for its synthesis. Three steps are required to synthesize siroheme from uroporphyrinogen III, the last common intermediate in the heme and siroheme pathways. All previously characterized cysG mutants were shown to be defective for the synthesis of cobalamin (B12), which shares a common precursor with siroheme. Since few cysG auxotrophs had been previously analyzed and since there is no evidence of siroheme mutants outside of the cysG region, we sought to expand the analysis of the region by isolating more mutations and studying the transcriptional regulation of the cysG gene using lacZ fusions. We isolated and analyzed 66 cysG auxotrophs. All were defective for both siroheme and cobalamin synthesis. Five exceptional mutants were partially defective for the synthesis of both and appear to be leaky. Complementation tests with tandem duplications suggest that the mutations causing the Cys auxotrophy affect only one cistron. The cysG gene is transcribed in a clockwise direction; this was demonstrated by a method that permits determining the orientation of two genes of unknown orientation provided their relative map order is known. The cysG gene was not part of the cysteine regulon, but had a substantial basal level of expression which was induced fivefold when cells were grown anaerobically on nitrite. Finally, we used Mud-generated duplications to genetically determine the organization of the cysG and nirB genes.
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Affiliation(s)
- B S Goldman
- Department of Biology, University of Utah, Salt Lake City 84112
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20
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Kredich NM. The molecular basis for positive regulation of cys promoters in Salmonella typhimurium and Escherichia coli. Mol Microbiol 1992; 6:2747-53. [PMID: 1435253 DOI: 10.1111/j.1365-2958.1992.tb01453.x] [Citation(s) in RCA: 130] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Most genes required for cysteine biosynthesis in Salmonella typhimurium and Escherichia coli are positively regulated by cysB, which encodes a transcriptional activator belonging to the LysR family of regulatory proteins. CysB protein binds just upstream of the -35 region of positively regulated promoters, where in the presence of inducer it facilitates formation of a transcription initiation complex. CysB protein also autoregulates its own synthesis by binding to the cysB promoter as a repressor. Cysteine down-regulates the pathway by inhibiting synthesis of O-acetylserine, a direct cysteine precursor and possibly an inducer of gene expression. O-Acetylserine spontaneously isomerizes to N-acetylserine, which is clearly an inducer. Sulphide and thiosulphate provide additional regulation by acting as anti-inducers. Inducer stimulates CysB protein binding to sites involved in positive regulation, and inhibits binding to the negatively autoregulated cysB promoter. For three sites with unknown function, binding is stimulated at one and inhibited at the other two.
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Affiliation(s)
- N M Kredich
- Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710
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21
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Grundy CE, Ayling PD. Fine structure mapping and complementation studies of the metD methionine transport system in Salmonella typhimurium. Genet Res (Camb) 1992; 60:1-6. [PMID: 1452012 DOI: 10.1017/s0016672300030603] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
A fine structure deletion map of the metD region of the chromosome of Salmonella typhimurium responsible for a high-affinity methionine transport system has been constructed. Complementation tests involving the introduction of metD+DNA contained in a pUC8 vector into metD strains indicated the presence of four complementation groups in the metD region. This suggested that the methionine system belongs to the osmotic shock-sensitive class of transport system, and therefore should possess a periplasmic methionine-binding protein and several membrane proteins. But a deletion mutation covering all known metD point mutations did not affect the level of a methionine binding activity in osmotic shock fluids, suggesting either that the deletion did not extend into the gene encoding the binding protein, or that the binding activity is not associated with the metD system. Possible reasons for the failure to isolate mutations in the gene for the binding protein are discussed.
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Affiliation(s)
- C E Grundy
- Department of Applied Biology, University of Hull
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22
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Abstract
Compounds of hexavalent chromium (chromates and dichromates) are highly toxic. Plasmid genetic determinants for chromate resistance have been described in several bacterial genera, most notably in Pseudomonas. Resistance to chromate is associated with decreased chromate transport by the resistant cells. The genes for a hydrophobic polypeptide, ChrA, were identified in chromate resistance plasmids of Pseudomonas aeruginosa and Alcaligenes eutrophus. ChrA is postulated to be responsible for the outward membrane translocation of chromate anions. Widespread bacterial reduction of hexavalent chromate to the less toxic trivalent chromic ions is also known. Chromate reduction determinants have not, however, been found on bacterial plasmids or transposons. In different bacteria, chromate reduction is either an aerobic or an anaerobic process (but not both) and is carried out either by soluble proteins or by cell membranes. Chromate reduction may also be a mechanism of resistance to chromate, but this has not been unequivocally shown.
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Affiliation(s)
- C Cervantes
- Instituto de Investigaciones Quimico-Biologicas, Universidad Michoacana, Morelia, Mexico
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23
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Hryniewicz MM, Kredich NM. The cysP promoter of Salmonella typhimurium: characterization of two binding sites for CysB protein, studies of in vivo transcription initiation, and demonstration of the anti-inducer effects of thiosulfate. J Bacteriol 1991; 173:5876-86. [PMID: 1909324 PMCID: PMC208322 DOI: 10.1128/jb.173.18.5876-5886.1991] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The cysPTWA operons of Escherichia coli and Salmonella typhimurium encode components of periplasmic transport systems for sulfate and thiosulfate and are regulated as part of the cysteine regulons. In vitro transcription initiation from the cysP promoter was shown to require both CysB protein and either O-acetyl-L-serine or N-acetyl-L-serine, which act as inducers, and was inhibited by the anti-inducer sulfide. Thiosulfate was found to be even more potent than sulfide as an anti-inducer. DNase I protection experiments showed two discrete binding sites for CysB protein in the presence of N-acetyl-L-serine. CBS-P1 is located between positions -85 and -41 relative to the major transcription start site, and CBS-P2 is located between positions -19 and +25. Without N-acetyl-L-serine, the CysB protein protected the region between positions -63 and -11, which was designated CBS-P3. In gel mobility shift assays, the mobility of CysB protein-cysP promoter complexes was increased by O-acetyl-L-serine, N-Acetyl-L-serine had no effect in gel shift experiments, presumably because its anionic charge results in its rapid removal from the complex during electrophoresis. Comparison of DNA fragments differing with respect to binding site position indicated that complexes with CysB protein contain DNA that is bent somewhere between CBS-P1 and CBS-P2 and that O-acetyl-L-serine decreases DNA bending. Binding studies with fragments containing either CBS-P2 alone, CBS-P1 alone, or the entire cysP promoter region suggest a model in which the complex of bent DNA observed in the absence of O-acetyl-L-serine contains a single CysB protein molecule bound to CBS-P3. At relatively low CysB protein concentrations, O-acetyl-L-serine would cause a single CysB protein molecule to bind tightly to CBS-P1, rather than to CBS-P3, thereby decreasing DNA bending and increasing complex electrophoretic mobility. At higher CysB protein concentrations, O-acetyl-L-serine would cause a second molecule to bind at CBS-P2, giving a more slowly migrating complex.
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Affiliation(s)
- M M Hryniewicz
- Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710
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24
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Laudenbach DE, Grossman AR. Characterization and mutagenesis of sulfur-regulated genes in a cyanobacterium: evidence for function in sulfate transport. J Bacteriol 1991; 173:2739-50. [PMID: 1708375 PMCID: PMC207853 DOI: 10.1128/jb.173.9.2739-2750.1991] [Citation(s) in RCA: 112] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
A sulfur-regulated gene (cysA) that encodes the membrane-associated ATP-binding protein of the sulfate transport system of the cyanobacterium Synechococcus sp. strain PCC 7942 was recently isolated and sequenced. Adjacent to cysA and transcribed in the opposite direction is a gene encoding the sulfate-binding protein (sbpA). Two other genes, cysT and cysW, encode proteins that may form a channel for the transport of sulfate across the cytoplasmic membrane. A fourth gene, cysR, located between cysT, and cysW, encodes a polypeptide that has some homology to a family of prokaryotic regulatory proteins. Mutant strains in which cysA, cysT, or cysW was interrupted by a drug resistance marker were not viable when grown with sulfate as the sole sulfur source and exhibited essentially no sulfate uptake. In contrast, sbpA and cysR mutants grew on sulfate, although they did not exhibit the 20-fold increase in the Vmax (concentration of sulfate at half-maximal transport rate) for sulfate transport characteristic of wild-type cells grown under sulfur-limiting conditions. Three of the sulfur-regulated genes in Synechococcus sp. strain PCC 7942 are similar to genes encoded by the chloroplast genome of the primitive plant Marchantia polymorpha. These data suggest that a sulfate transport system similar to that of Synechococcus sp. strain PCC 7942 may exist in the chloroplast envelope of photosynthetic eukaryotes.
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Affiliation(s)
- D E Laudenbach
- Department of Plant Biology, Carnegie Institution of Washington, Stanford, California 94305
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25
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Hryniewicz M, Sirko A, Pałucha A, Böck A, Hulanicka D. Sulfate and thiosulfate transport in Escherichia coli K-12: identification of a gene encoding a novel protein involved in thiosulfate binding. J Bacteriol 1990; 172:3358-66. [PMID: 2188959 PMCID: PMC209147 DOI: 10.1128/jb.172.6.3358-3366.1990] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The sequence of 1,973 nucleotides encompassing the region at and directly adjacent to the CysB-dependent promoter controlling expression and synthesis of the sulfate-thiosulfate transport system of Escherichia coli has been determined. The transcription start site has been mapped by primer extension. One open reading frame representing the first gene of the presumed sulfate transport operon was identified and designated cysP. The deduced amino acid sequence of the CysP polypeptide indicates the presence of a signal peptide. Expression of the cysP gene in the T7 promoter-polymerase system revealed the location of the gene product in the periplasm. Construction of a cysP insertional mutant and assays of binding and uptake of sulfate and thiosulfate by this mutant allowed the identification of the cysP gene product as a thiosulfate-binding protein. The TGA termination codon of cysP was found to overlap the putative ATG initiation codon of the next open reading frame, inferred as being essential for the sulfate transport system, and it was designated cysT. Preliminary sequence data from the corresponding region of the Salmonella typhimurium chromosome showed strictly homologous counterparts of the E. coli cysP and cysT genes.
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Affiliation(s)
- M Hryniewicz
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw
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26
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Sirko A, Hryniewicz M, Hulanicka D, Böck A. Sulfate and thiosulfate transport in Escherichia coli K-12: nucleotide sequence and expression of the cysTWAM gene cluster. J Bacteriol 1990; 172:3351-7. [PMID: 2188958 PMCID: PMC209146 DOI: 10.1128/jb.172.6.3351-3357.1990] [Citation(s) in RCA: 142] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The nucleotide sequence of the sulfate and thiosulfate transport gene cluster has been determined and located 3' to the gene (cysP) encoding the thiosulfate-binding protein. Four open reading frames, designated cysT, cysW, cysA, and cysM, have been identified. Similarities in primary structure were observed between (i) the deduced amino acid sequences of CysT and CysW with membrane-bound components of other binding protein-dependent transport systems, (ii) that of the CysA sequence with the "conserved" component of such systems, and (iii) that of the CysM sequence with O-acetylserine sulfhydrylase A (cysK gene product) and the beta-subunit of tryptophan synthase (coded by trpB). Expression of the four genes was analyzed in the T7 promoter-polymerase system.
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Affiliation(s)
- A Sirko
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw
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27
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Affiliation(s)
- U Wanner
- Swiss Federal Institute for Water Resources and Water Pollution Control, Swiss Federal Institutes of Technology, Dübendorf
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28
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Hughes D, Thompson S, O'Connor M, Tuohy T, Nichols BP, Atkins JF. Genetic characterization of frameshift suppressors with new decoding properties. J Bacteriol 1989; 171:1028-34. [PMID: 2644219 PMCID: PMC209697 DOI: 10.1128/jb.171.2.1028-1034.1989] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Suppressor mutants that cause ribosomes to shift reading frame at specific and new sequences are described. Suppressors for trpE91, the only known suppressible -1 frameshift mutant, have been isolated in Escherichia coli and in Salmonella typhimurium. E. coli hopR acts on trpE91 within the 9-base-pair sequence GGA GUG UGA, is dominant, and is located at min 52 on the chromosome. Its Salmonella homolog maps at an equivalent position and arises as a rarer class in that organism as compared with E. coli. The Salmonella suppressor, hopE, believed to be in a duplicate copy of the same gene, maps at min 17. The +1 suppressor, sufT, acts at the nonmonotonous sequence CCGU, is dominant, and maps at min 59 on the Salmonella chromosome.
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Affiliation(s)
- D Hughes
- Department of Genetics, Trinity College, Dublin, Ireland
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29
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Byrne CR, Monroe RS, Ward KA, Kredich NM. DNA sequences of the cysK regions of Salmonella typhimurium and Escherichia coli and linkage of the cysK regions to ptsH. J Bacteriol 1988; 170:3150-7. [PMID: 3290198 PMCID: PMC211262 DOI: 10.1128/jb.170.7.3150-3157.1988] [Citation(s) in RCA: 114] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Nucleotide sequences of the cysK regions of Salmonella typhimurium and Escherichia coli have been determined. A total of 3,812 and 2,595 nucleotides were sequenced from S. typhimurium and E. coli, respectively. Open reading frames of 323 codons were found in both species and were identified as those of cysK by comparison of deduced amino acid sequences with amino- and carboxyl-terminal amino acid analyses of the S. typhimurium cysK gene product O-acetylserine (thiol)-lyase A. The two cysK DNA sequences were 85% identical, and the deduced amino acid sequences were 96% identical. The major transcription initiation sites for cysK were found to be virtually identical in the two organisms, by using primer extension and S1 nuclease protection techniques. The -35 region corresponding to the major transcription start site was TTCCCC in S. typhimurium and TTCCGC in E. coli. The deviation of these sequences from the consensus sequence TTGACA may reflect the fact that cysK is subject to positive control and requires the cysB regulatory protein for expression. Sequences downstream of cysK were found to include ptsH and a portion of ptsI, thus establishing the exact relationship of cysK with these two genes. A 290-codon open reading frame, which may represent the cysZ gene, was identified upstream of cysK.
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Affiliation(s)
- C R Byrne
- Division of Animal Production, Commonwealth Scientific and Industrial Research Organisation, Blacktown, New South Wales, Australia
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30
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Lydiate DJ, Mendez C, Kieser HM, Hopwood DA. Mutation and cloning of clustered Streptomyces genes essential for sulphate metabolism. ACTA ACUST UNITED AC 1988. [DOI: 10.1007/bf00425694] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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31
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Ohtake H, Cervantes C, Silver S. Decreased chromate uptake in Pseudomonas fluorescens carrying a chromate resistance plasmid. J Bacteriol 1987; 169:3853-6. [PMID: 3112130 PMCID: PMC212482 DOI: 10.1128/jb.169.8.3853-3856.1987] [Citation(s) in RCA: 134] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
CrO4(2-) resistance in Pseudomonas fluorescens LB300(pLHB1) was related to reduced uptake of CrO4(2-) relative to the plasmidless strain LB303. 51CrO4(2-) was transported mainly via the SO4(2-) active transport system; thus, cells grown with 0.15 mM cysteine, a repressor of the SO4(2-) transport system, were much more resistant to CrO4(2-) than those grown with 0.15 mM djenkolic acid, which derepressed the 35SrO4(2-) uptake system. Kinetics of 51CrO4(2-) uptake by P. fluorescens with and without the plasmid showed that the Vmax for 51CrO4(2-) uptake with the resistant strain was 2.2 times less than the Vmax for the sensitive strain, whereas the Km remained constant.
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32
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Abstract
Spot 42 RNA of Escherichia coli, a 109-nucleotide RNA that influences the level of DNA polymerase I, has an AUG triplet preceded by a purine-rich potential ribosome-binding site and is followed by a short (14-triplet) potential open reading frame. Although the RNA bound to ribosomes, it did so inefficiently and nonproductively. When fused to lacZ sequences, spot RNA did not support the synthesis of beta-galactosidase. Also, the biological effects of spot 42 RNA were not altered by mutation of the tyrosine UAU codon to the chain termination UAG. We conclude that the effects of spot 42 RNA are mediated by the RNA itself and not by a spot 42 RNA-encoded peptide.
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33
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Barrett EL, Clark MA. Tetrathionate reduction and production of hydrogen sulfide from thiosulfate. Microbiol Rev 1987; 51:192-205. [PMID: 3299028 PMCID: PMC373103 DOI: 10.1128/mr.51.2.192-205.1987] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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34
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Giffard PM, Rowland GC, Kroll RG, Stewart LM, Bakker EP, Booth IR. Phenotypic properties of a unique rpoA mutation (phs) of Escherichia coli. J Bacteriol 1985; 164:904-10. [PMID: 2865250 PMCID: PMC214337 DOI: 10.1128/jb.164.2.904-910.1985] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The phs mutation of Escherichia coli has been suggested to affect the Na+/H+ antiport (D. Zilberstein, E. Padan, and S. Schuldiner, FEBS Lett. 168:327-330, 1980). We have recently shown that the mutation affects the rpoA gene and thus affects transcription. The extent of the pleiotropy of the phs mutation was investigated. In addition to the previously reported growth defect on L-glutamate and melibiose, the mutation also affects at least two other metabolic systems. The transport and metabolism of arabinose is impaired and the transport of sulfate is reduced. The extent to which the effects of the phs mutation on metabolism are due to a defect in the Na+/H+ antiport was investigated, and no causal role for this transport system in the metabolic defects was found.
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35
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García M, Benítez J, Delgado J, Kotyk A. Isolation of sulphate transport defective mutants of Candida utilis: further evidence for a common transport system for sulphate, sulphite and thiosulphate. Folia Microbiol (Praha) 1983; 28:1-5. [PMID: 6682073 DOI: 10.1007/bf02877376] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Selenate-resistant mutants of Candida utilis were isolated. They did not take up sulphate while incorporation of an organic sulphur source, such as L-methionine, was similar to the wild-type strain. They grew poorly on sulphate, sulphite and thiosulphate and, as expected, grew well on methionine. Sulphite reductase activities of the mutants were similar to the wild type strain. The properties of these mutants support the view of a common transport system for sulphate, sulphite and thiosulphate.
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36
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Abstract
Sulphate uptake by Candida utilis follows Michaelis-Menten type kinetics characterized by a Km of 1.43 mM for sulphate. The process is unidirectional, pH, temperature and energy dependent. Molybdate, selenate, thiosulphate, chromate and sulphite are competitive inhibitors. Dithionite is a mixed-type inhibitor of sulphate uptake. If cells are pre-incubated with sulphate, sulphite, thiosulphate, dithionite or sulphide, sulphate uptake is severely blocked. Inhibition by endogenous sulphate, sulphite and thiosulphate was specific for sulphate uptake. Thus, incorporation of extracellular sulphate seems to be under the control of a heterogeneous pool of sulphur compounds. These results are discussed in connection with the regulation of sulphur amino acid biosynthesis in C. utilis.
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37
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Hulanicka MD, Hallquist SG, Kredich NM, Mojica-A T. Regulation of O-acetylserine sulfhydrylase B by L-cysteine in Salmonella typhimurium. J Bacteriol 1979; 140:141-6. [PMID: 387718 PMCID: PMC216789 DOI: 10.1128/jb.140.1.141-146.1979] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
A technique based on resistance to azaserine was used to isolate mutants lacking O-acetylserine sulfhydrylase B, one of two enzymes in Salmonella typhimurium capable of synthesizing L-cysteine from O-acetyl-L-serine and sulfide. The mutant locus responsible for this defect has been designated cysM, and genetic mapping suggests that cysM is very close to and perhaps contiguous with cysA. Strains lacking either O-acetylserine sulfhydrylase B or the second sulfhydrylase, O-acetylserine sulfhydrylase A (coded for by cysK), are cysteine prototrophs, but cysK cysM double mutants were found to require cysteine for growth. O-Acetylserine sulfhydrylase B was depressed by growth on a poor sulfur source, and depression was dependent upon both a functional cysB regulatory gene product and the internal inducer of the cysteine biosynthetic pathway, O-acetyl-L-serine. Furthermore, a cysBc strain, in which other cysteine biosynthetic enzymes cannot be fully repressed by growth on L-cystine, was found to be constitutive for O-acetylserine sulfhydrylase B as well. Thus O-acetylserine sulfhydrylase B is regulated by the same factors that control the expression of O-acetylserine sulfhydrylase A and other activities of the cysteine regulon. It is not clear why S. typhimurium has two enzymes whose physiological function appears to be to catalyze the same step of L-cysteine biosynthesis.
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38
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Galloway DR, Furlong CE. The role of ribose-binding protein in transport and chemotaxis in Escherichia coli K12. Arch Biochem Biophys 1977; 184:496-504. [PMID: 339843 DOI: 10.1016/0003-9861(77)90459-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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39
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Whipp MJ, Pittard AJ. Regulation of aromatic amino acid transport systems in Escherichia coli K-12. J Bacteriol 1977; 132:453-61. [PMID: 334742 PMCID: PMC221884 DOI: 10.1128/jb.132.2.453-461.1977] [Citation(s) in RCA: 75] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The regulation of the aromatic amino acid transport systems was investigated. The common (general) aromatic transport system and the tyrosine-specific transport system were found to be subject to repression control, thus confirming earlier reports. In addition, tryosine- and tryptophan-specific transport were found to be enhanced by growth of cells with phenylalanine. The repression and enhancement of the transport systems was abolished in a strain carrying an amber mutation in the regulator gene tyrR. This indicates that the tyrR gene product, which was previously shown to be involved in regulation of aromatic biosynthetic enzymes, is also involved in the regulation of the aromatic amino acid transport systems.
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40
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Abstract
Sulfate transport by tobacco (Nicotiana tabacum L. var. Xanthi) cells cultured on either l-cysteine or sulfate as a sole sulfur source was measured. The transport rate on either sulfur source was low during pre-exponential growth, increased during exponential growth, and was maximal in late exponential cells. The initial increase in transport rate was correlated with a decline in the intracellular sulfate, but was not correlated with the amino acid content of the cells which remained relatively constant before the depletion of the endogenous sulfate pool. The previously reported inhibition of sulfate transport by l-cysteine was shown to be caused by an elevation in intracellular sulfate resulting from the degradation of cysteine to sulfate. It is proposed that the intracellular sulfate pool is the major factor regulating the entry of sulfate into tobacco cells.
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Affiliation(s)
- I K Smith
- Department of Botany, Ohio University, Athens, Ohio 45701
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41
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Cordaro JC, Anderson RP, Grogan EW, Wenzel DJ, Engler M, Roseman S. Promoter-like mutation affecting HPr and enzyme I of the phosphoenolpyruvate: sugar phosphotransferase system in Salmonella typhimurium. J Bacteriol 1974; 120:245-52. [PMID: 4608878 PMCID: PMC245757 DOI: 10.1128/jb.120.1.245-252.1974] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
A promoter-like mutation, ptsP160, has been identified which drastically reduces expression of the genes specifying two proteins, HPr and enzyme I, of the phosphoenolpyruvate:sugar phosphotransferase system (PTS) in Salmonella typhimurium. This mutation lies between trzA, a gene specifying susceptibility to 1,2,4-triazole, and ptsH, the structural gene for HPr. It leads to a loss of active transport of those sugars that require the PTS for entry into the cell. Pseudorevertants of strains carrying this promoter-like mutation have additional lesions very closely linked to ptsP160 by transduction analysis and are noninducible for HPr and enzyme I above a basal level. Presumably, strains carrying ptsP160 are defective in the normal induction mechanism for HPr and enzyme I, and the pseudorevertants derived from them result from second-site initiation signals within or near this promoter-like element. The induction of HPr and enzyme I above their noninduced levels apparently is not required for transport of at least one PTS sugar, methyl alpha-d-glucopyranoside, since this sugar is taken up by the pseudorevertants at the same rate as by the wild type. The existence of a promoter-like element governing the coordinate inducibility of both HPr and enzyme I suggests that ptsH and ptsI constitute an operon. Wild-type levels of a sugar-specific PTS protein, factor III, are synthesized in response to the crr(+) gene in both a ptsP160 strain and its pseudorevertants; this suggests that the crr(+) gene has its own promoter distinct from ptsP.
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Boos W. Pro and Contra Carrier Proteins; Sugar Transport via the Periplasmic Galactose-Binding Protein. CURRENT TOPICS IN MEMBRANES AND TRANSPORT 1974. [DOI: 10.1016/s0070-2161(08)60184-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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Slayman CW. The Genetic Control of Membrane Transport. CURRENT TOPICS IN MEMBRANES AND TRANSPORT VOLUME 4 1974. [DOI: 10.1016/s0070-2161(08)60847-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
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Berger EA, Heppel LA. A Binding Protein Involved in the Transport of Cystine and Diaminopimelic Acid in Escherichia coli. J Biol Chem 1972. [DOI: 10.1016/s0021-9258(19)44579-1] [Citation(s) in RCA: 83] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Cordaro JC, Roseman S. Deletion mapping of the genes coding for HPr and enzyme I of the phosphoenolpyruvate: sugar phosphotransferase system in Salmonella typhimurium. J Bacteriol 1972; 112:17-29. [PMID: 4562394 PMCID: PMC251376 DOI: 10.1128/jb.112.1.17-29.1972] [Citation(s) in RCA: 97] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Sugars transported by a bacterial phosphoenolpyruvate:sugar phosphotransferase system (PTS) require two soluble proteins: HPr, a low-molecular-weight phosphate-carrier protein, and enzyme I. The structural genes coding for HPr (ptsH) and Enzyme I (ptsI) are shown to be cotransducible in Salmonella typhimurium. The gene order of this region of the Salmonella chromosome is cysA-trzA-ptsH-ptsI...(crr). A method for the isolation of trzA-pts deletion is described. One class of pts deletions extends through ptsH and into ptsI; a second class includes both ptsH and ptsI and extends into or through the crr gene. The crr gene either codes for or regulates the synthesis of a third PTS protein (factor III) which is sugar-specific. A hypothesis is presented for a mechanism of deletion formation.
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Structurally Defective Galactose-binding Protein Isolated from a Mutant Negative in the β-Methylgalactoside Transport System of Escherichia coli. J Biol Chem 1972. [DOI: 10.1016/s0021-9258(20)81121-1] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Harold FM. Conservation and transformation of energy by bacterial membranes. BACTERIOLOGICAL REVIEWS 1972; 36:172-230. [PMID: 4261111 PMCID: PMC408323 DOI: 10.1128/br.36.2.172-230.1972] [Citation(s) in RCA: 331] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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