151
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Criddle CS, DeWitt JT, McCarty PL. Reductive dehalogenation of carbon tetrachloride by Escherichia coli K-12. Appl Environ Microbiol 1990; 56:3247-54. [PMID: 2268147 PMCID: PMC184937 DOI: 10.1128/aem.56.11.3247-3254.1990] [Citation(s) in RCA: 65] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The formation of radicals from carbon tetrachloride (CT) is often invoked to explain the product distribution resulting from its transformation. Radicals formed by reduction of CT presumably react with constituents of the surrounding milieu to give the observed product distribution. The patterns of transformation observed in this work were consistent with such a hypothesis. In cultures of Escherichia coli K-12, the pathways and rates of CT transformation were dependent on the electron acceptor condition of the media. Use of oxygen and nitrate as electron acceptors generally prevented CT metabolism. At low oxygen levels (approximately 1%), however, transformation of [14C]CT to 14CO2 and attachment to cell material did occur, in accord with reports of CT fate in mammalian cell cultures. Under fumarate-respiring conditions, [14C]CT was recovered as 14CO2, chloroform, and a nonvolatile fraction. In contrast, fermenting conditions resulted in more chloroform, more cell-bound 14C, and almost no 14CO2. Rates of transformation of CT were faster under fermenting conditions than under fumarate-respiring conditions. Transformation rates also decreased over time, suggesting the gradual exhaustion of transformation activity. This loss was modeled with a simple exponential decay term.
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Affiliation(s)
- C S Criddle
- Environmental Engineering and Science, Stanford University, California 94305-4020
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152
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Schlindwein C, Giordano G, Santini CL, Mandrand MA. Identification and expression of the Escherichia coli fdhD and fdhE genes, which are involved in the formation of respiratory formate dehydrogenase. J Bacteriol 1990; 172:6112-21. [PMID: 2170340 PMCID: PMC526937 DOI: 10.1128/jb.172.10.6112-6121.1990] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The two closely linked fdhD and fdhE genes of Escherichia coli are required for the formation of active membrane-bound phenazine methosulfate-linked formate dehydrogenase (FDH-PMS). Both genes were isolated from a cosmid library. Restriction endonuclease analysis associated with Mu dII1734 insertion mutagenesis indicated that the two genes were separated by at least 4 kilobases and transcribed in opposite orientations. Initial experiments indicate that the region between the two genes seems not to be essential to FDH-PMS activity. fdhD and fdhE were expressed either in maxicells or from the T7 promoter-polymerase system. They were shown to encode proteins with approximate Mr 30,500 and 32,000, respectively. Both proteins appeared in the soluble fraction and were not recognized by an FDH-PMS-specific antiserum. Therefore, neither fdhD nor fdhE plays a structural role in the formation of FDH-PMS. Expression of a phi(fdhD-lacZ) operon fusion was decreased about threefold by aerobiosis but was indifferent to other effectors tested. It was unaffected by pfl, chlA, selA, and fnr mutations. Expression of a phi(fdhE-lacZ) operon fusion was slightly induced by nitrate. This induction, requiring the presence of functional chl and fnr alleles, was mediated via nitrate metabolism. Transcription of phi(fdhE-lacZ) fusion was fully dependent on wild-type sel alleles. This might suggest the participation of fdhE in the synthesis of the selenopolypeptide of FDH-PMS.
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Affiliation(s)
- C Schlindwein
- Unité Mixte 24 du Centre National de la Recherche Scientifique, Institut National des Sciences Appliquées de Lyon, France
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153
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Sambasivarao D, Scraba DG, Trieber C, Weiner JH. Organization of dimethyl sulfoxide reductase in the plasma membrane of Escherichia coli. J Bacteriol 1990; 172:5938-48. [PMID: 2170332 PMCID: PMC526915 DOI: 10.1128/jb.172.10.5938-5948.1990] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Dimethyl sulfoxide reductase is a trimeric, membrane-bound, iron-sulfur molybdoenzyme induced in Escherichia coli under anaerobic growth conditions. The enzyme catalyzes the reduction of dimethyl sulfoxide, trimethylamine N-oxide, and a variety of S- and N-oxide compounds. The topology of dimethyl sulfoxide reductase subunits was probed by a combination of techniques. Immunoblot analysis of the periplasmic proteins from the osmotic shock and chloroform wash fluids indicated that the subunits were not free in the periplasm. The reductase was susceptible to proteases in everted membrane vesicles, but the enzyme in outer membrane-permeabilized cells became protease sensitive only after detergent solubilization of the E. coli plasma membrane. Lactoperoxidase catalyzed the iodination of each of the three subunits in an everted membrane vesicle preparation. Antibodies to dimethyl sulfoxide reductase and fumarate reductase specifically agglutinated the everted membrane vesicles. No TnphoA fusions could be found in the dmsA or -B genes, indicating that these subunits were not translocated to the periplasm. Immunogold electron microscopy of everted membrane vesicles and thin sections by using antibodies to the DmsABC, DmsA, DmsB subunits resulted in specific labeling of the cytoplasmic surface of the inner membrane. These results show that the DmsA (catalytic subunit) and DmsB (electron transfer subunit) are membrane-extrinsic subunits facing the cytoplasmic side of the plasma membrane.
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Affiliation(s)
- D Sambasivarao
- Department of Biochemistry, University of Alberta, Edmonton, Canada
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154
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The use of gene fusions to determine the topology of all of the subunits of the cytochrome o terminal oxidase complex of Escherichia coli. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)38256-0] [Citation(s) in RCA: 93] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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155
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MacInnes JI, Kim JE, Lian CJ, Soltes GA. Actinobacillus pleuropneumoniae hlyX gene homology with the fnr gene of Escherichia coli. J Bacteriol 1990; 172:4587-92. [PMID: 2198268 PMCID: PMC213292 DOI: 10.1128/jb.172.8.4587-4592.1990] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The hlyX gene from Actinobacillus pleuropneumoniae, which confers a hemolytic phenotype on Escherichia coli, was sequenced, and its role in regulation of gene expression was investigated. No similarity was found between the hlyX sequence and sequences of known hemolysin or cytotoxin genes. However, the hlyX sequence was very similar to that of the fnr gene of Escherichia coli which encodes the global regulatory protein, FNR. Comparison of the deduced amino acid sequence of the hlyX gene product (HlyX) with that of FNR revealed a high degree of well-aligned sequence correlation throughout the polypeptide chain. For example, 23 of 24 amino acids in the DNA-binding region of FNR are identical in the corresponding region of HlyX. Four cysteine residues in the amino-terminal region are also conserved. The promoter region of hlyX is very similar to that of fnr. It has a putative -10 sequence which closely resembles the E. coli -10 consensus sequence. This sequence is overlapped by a potential operator which is very similar to the FNR-binding-site consensus sequence. Functional homology between HlyX and FNR was also demonstrated. Plasmids carrying hlyX complemented the nutritional lesion of an fnr deletion strain of E. coli. These data suggest that HlyX may regulate, rather than mediate, hemolytic activity in E. coli, but the possibility that HlyX is both a regulator of gene expression and a hemolysin cannot be excluded.
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Affiliation(s)
- J I MacInnes
- Department of Veterinary Microbiology and Immunology, University of Guelph, Ontario, Canada
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156
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The sequence of the cyo operon indicates substantial structural similarities between the cytochrome o ubiquinol oxidase of Escherichia coli and the aa3-type family of cytochrome c oxidases. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)38574-6] [Citation(s) in RCA: 183] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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157
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Wissenbach U, Kröger A, Unden G. The specific functions of menaquinone and demethylmenaquinone in anaerobic respiration with fumarate, dimethylsulfoxide, trimethylamine N-oxide and nitrate by Escherichia coli. Arch Microbiol 1990; 154:60-6. [PMID: 2204318 DOI: 10.1007/bf00249179] [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]
Abstract
The respiratory activities of E. coli with H2 as donor and with nitrate, fumarate, dimethylsulfoxide (DMSO) or trimethylamine N-oxide (TMAO) as acceptor were measured using the membrane fraction of quinone deficient strains. The specific activities of the membrane fraction lacking naphthoquinones with fumarate, DMSO or TMAO amounted to less than or equal to 2% of those measured with the membrane fraction of the wild-type strain. After incorporation of vitamin K1 [instead of menaquinone (MK)] into the membrane fraction deficient of naphthoquinones, the activities with fumarate or DMSO were 92% or 17%, respectively, of the activities which could be theoretically achieved. Incorporation of demethylmenaquinone (DMK) did not lead to a stimulation of the activities of the mutant. In contrast, the electron transport activity with TMAO was stimulated by the incorporation of either vitamin K1 or DMK. Nitrate respiration was fully active in membrane fractions lacking either naphthoquinones or Q, but was less than or equal to 3% of the wild-type activity, when all quinones were missing. Nitrate respiration was stimulated on the incorporation of either vitamin K1 or Q into the membrane fraction lacking quinones, while the incorporation of DMK was without effect. These results suggest that MK is specifically involved in the electron transport chains catalyzing the reduction of fumarate or DMSO, while either MK or DMK serve as mediators in TMAO reduction. Nitrate respiration requires either Q or MK.
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Affiliation(s)
- U Wissenbach
- Institut für Mikrobiologie, J. W. Goethe-Universität, Frankfurt/Main, Federal Republic of Germany
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158
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Hill S, Viollet S, Smith AT, Anthony C. Roles for enteric d-type cytochrome oxidase in N2 fixation and microaerobiosis. J Bacteriol 1990; 172:2071-8. [PMID: 2156809 PMCID: PMC208706 DOI: 10.1128/jb.172.4.2071-2078.1990] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Escherichia coli strains that lacked the d-type cytochrome oxidase, the terminal oxidase with a high affinity for O2, grew anaerobically as well as the wild type did and were not impaired in the ability to evolve H2 from either glucose or formate. The anaerobic synthesis and activity of nitrogenase in transconjugants of these strains carrying Klebsiella pneumoniae nif genes were also normal. However, the behavior towards O2 of anaerobically grown bacteria lacking the d-type oxidase differed from that of the wild type in the following ways: the potential O2 uptake was lower, H2 evolution and nitrogenase activity supported by fermentation were more strongly inhibited by O2, and microaerobic O2-dependent nitrogenase activity in the absence of a fermentable carbon source did not occur. These results show that the d-type oxidase serves two functions in enteric bacteria--to conserve energy under microaerobic conditions and to protect anaerobic processes from inhibition by O2.
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Affiliation(s)
- S Hill
- Nitrogen Fixation Laboratory, AFRC Institute of Plant Science Research, University of Sussex, Brighton, United Kingdom
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159
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Salerno JC, Bolgiano B, Poole RK, Gennis RB, Ingledew WJ. Heme-copper and heme-heme interactions in the cytochrome bo-containing quinol oxidase of Escherichia coli. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)39573-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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160
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Multiple regulatory elements for the glpA operon encoding anaerobic glycerol-3-phosphate dehydrogenase and the glpD operon encoding aerobic glycerol-3-phosphate dehydrogenase in Escherichia coli: further characterization of respiratory control. J Bacteriol 1990; 172:179-84. [PMID: 2403539 PMCID: PMC208416 DOI: 10.1128/jb.172.1.179-184.1990] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
In Escherichia coli, sn-glycerol-3-phosphate can be oxidized by two different flavo-dehydrogenases, an anaerobic enzyme encoded by the glpACB operon and an aerobic enzyme encoded by the glpD operon. These two operons belong to the glp regulon specifying the utilization of glycerol, sn-glycerol-3-phosphate, and glycerophosphodiesters. In glpR mutant cells grown under conditions of low catabolite repression, the glpA operon is best expressed anaerobically with fumarate as the exogenous electron acceptor, whereas the glpD operon is best expressed aerobically. Increased anaerobic expression of glpA is dependent on the fnr product, a pleiotropic activator of genes involved in anaerobic respiration. In this study we found that the expression of a glpA1(Oxr) (oxygen-resistant) mutant operon, selected for increased aerobic expression, became less dependent on the FNR protein but more dependent on the cyclic AMP-catabolite gene activator protein complex mediating catabolite repression. Despite the increased aerobic expression of glpA1(Oxr), a twofold aerobic repressibility persisted. Moreover, anaerobic repression by nitrate respiration remained normal. Thus, there seems to exist a redox control apart from the FNR-mediated one. We also showed that the anaerobic repression of the glpD operon was fully relieved by mutations in either arcA (encoding a presumptive DNA recognition protein) or arcB (encoding a presumptive redox sensor protein). The arc system is known to mediate pleiotropic control of genes of aerobic function.
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161
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Andersson DI, Roth JR. Redox regulation of the genes for cobinamide biosynthesis in Salmonella typhimurium. J Bacteriol 1989; 171:6734-9. [PMID: 2687249 PMCID: PMC210570 DOI: 10.1128/jb.171.12.6734-6739.1989] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Transcription of the cobinamide biosynthetic genes (the CobI operon) was induced under three different physiological conditions: anaerobiosis (anaerobic respiration or fermentation), aerobic respiration at low oxygen levels, and aerobic respiration with a partial block of the electron transport chain. After a shift to inducing conditions, there was a time lag of approximately 50 min before the onset of CobI induction. Under conditions of anaerobic respiration, the level of CobI transcription was dependent on the nature of both the electron donor (carbon and energy source) and the acceptor. Cells grown with electron acceptors with a lower midpoint potential showed higher CobI expression levels. The highest level of CobI transcription observed was obtained with glycerol as the carbon source and fumarate as the electron acceptor. The high induction seen with glycerol was reduced by mutational blocks in the glycerol catabolic pathway, suggesting that glycerol does not serve as a gratuitous inducer but must be metabolized to stimulate CobI transcription. In the presence of oxygen, CobI operon expression was induced 6- to 20-fold by the following: inhibition of cytochrome o oxidase with cyanide, mutational blockage of ubiquinone biosynthesis, and starvation of mutant cells for heme. We suggest that the CobI operon is induced in response to a reducing environment within the cell and not by the absence of oxygen per se.
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Affiliation(s)
- D I Andersson
- Department of Biology, University of Utah, Salt Lake City 84112
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162
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Alam KY, Clark DP. Anaerobic fermentation balance of Escherichia coli as observed by in vivo nuclear magnetic resonance spectroscopy. J Bacteriol 1989; 171:6213-7. [PMID: 2681156 PMCID: PMC210491 DOI: 10.1128/jb.171.11.6213-6217.1989] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Fermenting anaerobic cultures of Escherichia coli were observed by the nonintrusive technique of in vivo, whole-culture nuclear magnetic resonance. Fermentation balances were calculated for hexoses, pentoses, sugar alcohols, and sugar acids. Substrates more reduced than glucose yielded more of the highly reduced fermentation product ethanol, whereas more-oxidized substrates produced more of the less-reduced fermentation product acetate. These relationships were made more obvious by the introduction of ldhA mutations, which abolished lactate production, and delta frd mutations, which eliminated succinate. When grown anaerobically on sugar alcohols such as sorbitol, E. coli produced ethanol in excess of the amount calculated by the standard fermentation pathways. Reducing equivalents must be recycled from formate to account for this excess of ethanol. In mutants deficient in hydrogenase (hydB), ethanol production from sorbitol was greatly decreased, implying that hydrogen gas released from formate by the formate-hydrogen lyase system may be partially recycled, in the wild type, to increase the yield of the highly reduced fermentation product ethanol.
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Affiliation(s)
- K Y Alam
- Department of Microbiology, Southern Illinois University, Carbondale 62901
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163
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Blaut M, Whittaker K, Valdovinos A, Ackrell BA, Gunsalus RP, Cecchini G. Fumarate Reductase Mutants of Escherichia coli That Lack Covalently Bound Flavin. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(18)80039-4] [Citation(s) in RCA: 89] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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164
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Cotter PA, Gunsalus RP. Oxygen, nitrate, and molybdenum regulation of dmsABC gene expression in Escherichia coli. J Bacteriol 1989; 171:3817-23. [PMID: 2544558 PMCID: PMC210130 DOI: 10.1128/jb.171.7.3817-3823.1989] [Citation(s) in RCA: 112] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Escherichia coli can respire anaerobically using either trimethylamine-N-oxide (TMAO) or dimethyl sulfoxide (DMSO) as the terminal electron acceptor for oxidative phosphorylation. To determine whether the regulation of the dmsABC genes, which encode a membrane-associated TMAO/DMSO reductase, are transcriptionally controlled in response to the availability of alternate electron acceptors, we constructed an operon fusion between the dmsA gene, along with its associated regulatory region, and lacZ+. Expression of dmsA'-lacZ was stimulated 65-fold by anaerobiosis versus aerobiosis, while nitrate caused a 12-fold repression. Its expression, however, was unaffected by the presence of the alternate electron acceptors DMSO, TMAO, and fumarate. Anaerobic induction of dmsA'-lacZ was defective in an fnr mutant, thus establishing that Fnr is responsible for anaerobic activation of dmsABC. Repression of dmsA'-lacZ expression by nitrate was independent of oxygen and was shown to be mediated by the products of two genes, narL (frdR2) and narX. dmsA'-lacZ expression was also altered in chlD strains that are defective in molybdenum transport but not in chlA and chlE strains that are defective in molybdopterin cofactor biosynthesis, thus establishing that the molybdenum ion but not the ability to form a functional cofactor is required for regulation. Molybdenum was required both for complete induction of dmsA'-lacZ expression during anaerobic growth and for complete repression of dmsA'-lacZ by nitrate. Additionally, expression of dmsABC varied depending on the carbon source. Expression was highest when cells were grown on sorbitol.
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Affiliation(s)
- P A Cotter
- Department of Microbiology, University of California, Los Angeles
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165
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Kalman LV, Gunsalus RP. Identification of a second gene involved in global regulation of fumarate reductase and other nitrate-controlled genes for anaerobic respiration in Escherichia coli. J Bacteriol 1989; 171:3810-6. [PMID: 2544557 PMCID: PMC210129 DOI: 10.1128/jb.171.7.3810-3816.1989] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Fumarate reductase catalyzes the final step of anaerobic electron transport in Escherichia coli when fumarate is used as a terminal electron acceptor. Transcription of the fumarate reductase operon (frdABCD) was repressed when cells were grown in the presence of either of the preferred terminal electron acceptors, oxygen or nitrate, and was stimulated modestly by fumarate. We have previously identified a locus called frdR which pleiotropically affects nitrate repression of fumarate reductase, trimethylamine N-oxide reductase, and alcohol dehydrogenase gene expression and nitrate induction of nitrate reductase expression (L. V. Kalman and R. P. Gunsalus, J. Bacteriol. 170:623-629, 1988). Transformation of various frdR mutants with plasmids identified two complementation groups, indicating that the frdR locus is composed of two genes. One class of mutants was not completely restored to wild-type frdA-lacZ expression or nitrate reductase induction when complemented with multicopy narX+ plasmids, whereas low-copy narX+ plasmid-containing strains were. A second class of frdR mutants was identified and shown to correspond to a previously described gene, narL (frdR2). Complementation of these strains with multicopy narL+ plasmids resulted in superrepression of frdA-lacZ expression and moderate elevation of nitrate reductase expression. Multicopy plasmids containing both narL+ and narX+ or only narL+ were able to complement narL mutants, whereas narX+ plasmids complemented narX mutants only when present in a copy number approximately equal to that of narL. Both narL and narX mutants retained normal oxygen control of frdA-lacZ expression. Both types of mutants are pleiotropic, as evidenced by derepressed levels of the fumarate reductase and trimethylamine N-oxide reductase enzymes and by defective induction of nitrate reductase when cells were grown in the presence of nitrate. These results indicate that both the narL and narX gene products must be present in a defined ratio in the cell. We conclude that these proteins interact to effect normal nitrate control of the anaerobic electron transport-associated operons. From these studies, we propose that narX encodes a nitrate sensor protein while narL encodes a DNA-binding regulatory protein which together function in a manner analogous to other two-component regulatory systems.
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Affiliation(s)
- L V Kalman
- Department of Microbiology, University of California, Los Angeles
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166
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Gupta S, Clark DP. Escherichia coli derivatives lacking both alcohol dehydrogenase and phosphotransacetylase grow anaerobically by lactate fermentation. J Bacteriol 1989; 171:3650-5. [PMID: 2661531 PMCID: PMC210107 DOI: 10.1128/jb.171.7.3650-3655.1989] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Escherichia coli mutants lacking alcohol dehydrogenase (adh mutants) cannot synthesize the fermentation product ethanol and are unable to grow anaerobically on glucose and other hexoses. Similarly, phosphotransacetylase-negative mutants (pta mutants) neither excrete acetate nor grow anaerobically. However, when a strain carrying an adh deletion was selected for anaerobic growth on glucose, spontaneous pta mutants were isolated. Strains carrying both adh and pta mutations were observed by in vivo nuclear magnetic resonance and shown to produce lactic acid as the major fermentation product. Various combinations of adh pta double mutants regained the ability to grow anaerobically on hexoses, by what amounts to a homolactic fermentation. Unlike wild-type strains, such adh pta double mutants were unable to grow anaerobically on sorbitol or on glucuronic acid. The growth properties of strains carrying various mutations affecting the enzymes of fermentation are discussed in terms of redox balance.
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Affiliation(s)
- S Gupta
- Department of Microbiology, Southern Illinois University, Carbondale 62901
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167
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McEwan AG, Kaplan S, Donohue TJ. Synthesis ofRhodobacter sphaeroidescytochromec2inEscherichia coli. FEMS Microbiol Lett 1989. [DOI: 10.1111/j.1574-6968.1989.tb03120.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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168
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Chin AM, Feldheim DA, Saier MH. Altered transcriptional patterns affecting several metabolic pathways in strains of Salmonella typhimurium which overexpress the fructose regulon. J Bacteriol 1989; 171:2424-34. [PMID: 2496106 PMCID: PMC209917 DOI: 10.1128/jb.171.5.2424-2434.1989] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Expression of beta-galactosidase in transcriptional fusions with the pps gene (encoding phosphoenolpyruvate [PEP] synthase), the aceBAK operon (encoding malate synthase, isocitrate lyase, and isocitrate dehydrogenase kinase, respectively), and the phs operon (encoding either thiosulfate reductase or a regulatory protein controlling its expression) was studied in Salmonella typhimurium. beta-Galactosidase synthesis in these strains was repressible either by growth in the presence of glucose or by the presence of a fruR mutation, which resulted in the constitutive expression of the fructose (fru) regulon. Five enzymes of gluconeogenesis (PEP synthase, PEP carboxykinase, isocitrate lyase, malate synthase, and fructose-1,6-diphosphatase) were shown to be repressed either by growth in the presence of glucose or the fruR mutation, while the glycolytic enzymes, enzyme I and enzymes II of the phosphotransferase system as well as phosphofructokinase, were induced either by growth in the presence of glucose or the fruR mutation. Overexpression of the cloned fru regulon genes (not including fruR) resulted in parallel repression of representative gluconeogenic, Krebs cycle, and glyoxylate shunt enzymes. Studies with temperature-sensitive mutants of S. typhimurium which synthesized heat-labile IIIFru proteins provided evidence that this protein plays a role in the regulation of gluconeogenic substrate utilization. Other mutant analyses revealed a complex relationship between fru gene expression and the expression of genes encoding gluconeogenic enzymes. Taken together, the results suggest that a number of genes encoding catabolic, biosynthetic, and amphibolic enzymes in enteric bacteria are transcriptionally regulated by a complex catabolite repression/activation mechanism which may involve enzyme IIIFru of the phosphotransferase system as one component of the regulatory system.
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Affiliation(s)
- A M Chin
- Department of Biology, University of California, San Diego, La Jolla 92093
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169
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Nohno T, Noji S, Taniguchi S, Saito T. The narX and narL genes encoding the nitrate-sensing regulators of Escherichia coli are homologous to a family of prokaryotic two-component regulatory genes. Nucleic Acids Res 1989; 17:2947-57. [PMID: 2657652 PMCID: PMC317704 DOI: 10.1093/nar/17.8.2947] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The nucleotide sequence of a 4.4-kilobase SacII-SspI fragment encoding the narXL operon and a part of the narK gene of Escherichia coli has been determined. The narX and narL genes encode proteins of molecular weight 67,275 and 23,927, respectively, and are transcribed from a common promoter, narXp, locating within 429 bases upstream of narX. Transcription from narXp is not significantly induced by nitrate under anaerobiosis, whereas transcription from narK promoter, which overlaps narXp region and is transcribed divergently, is fully induced by nitrate. The N-terminal two-thirds of the NarL protein has extensive homology with those of a diverse set of prokaryotic regulatory proteins, including OmpR, PhoB, SfrA, UhpA, CheY, CheB, NtrC, DctD, FixJ, VirG, SpoOF, and SpoOA. A segment locating in the C-terminal half of the NarL protein seems to have potential most likely to form the helix-turn-helix structure characteristic of a class of DNA-binding protein. The protein is considered to play a role as a transcriptional activator of the nitrate reductase operon, narCHJI, and the narK gene. The C-terminal region of the NarX protein also has homology with other regulatory proteins known as counterparts of two-component regulatory systems, such as EnvZ, PhoR, PhoM, CpxA, NtrB, DctB, FixL, and VirA. Presence of two copies of hydrophobic segments in the N-terminal half of the NarX protein suggests the role as a transmembrane receptor sensing nitrate.
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Affiliation(s)
- T Nohno
- Department of Pharmacology, Kawasaki Medical School, Japan
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170
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Gunsalus RP, Kalman LV, Stewart RR. Nucleotide sequence of the narL gene that is involved in global regulation of nitrate controlled respiratory genes of Escherichia coli. Nucleic Acids Res 1989; 17:1965-75. [PMID: 2648330 PMCID: PMC317536 DOI: 10.1093/nar/17.5.1965] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The DNA sequence was determined for the narL gene of Escherichia coli. This gene is involved in global regulation of a number of nitrate controlled genes including frdABCD, tor, narGHJI, and adhE which are associated with bacterial respiration and fermentation. Comparison of the deduced amino acid sequence of narL to that of other bacterial genes revealed significant homologies to the phoB, ompR, and virG gene products based on the presence of similar protein domains. These DNA binding proteins are members of two-component regulatory systems. The similarities suggest that narL may also participate in such a two-component regulatory system and that the narR gene, which lies upstream of narL, may encode a second component required for nitrate control of gene regulation. In vitro protein synthesis experiments using a narL plasmid identified a putative NarL protein of 29 kDa in size consistent with the DNA sequence analysis. Primer extension experiments revealed the presence of two 5' termini for narL mRNA, and indicates that transcription may be complex.
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Affiliation(s)
- R P Gunsalus
- Department of Microbiology, University of California, Los Angeles 90024
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171
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Frey B, Jänel G, Michelsen U, Kersten H. Mutations in the Escherichia coli fnr and tgt genes: control of molybdate reductase activity and the cytochrome d complex by fnr. J Bacteriol 1989; 171:1524-30. [PMID: 2537821 PMCID: PMC209776 DOI: 10.1128/jb.171.3.1524-1530.1989] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
In eubacteria, the tRNA transglycosylase (Tgt) in specific tRNAs exchanges a guanine in the anticodon for 7-aminomethyl-7-deazaguanine, which is finally converted to queuosine. The tgt gene of Escherichia coli has been mapped at 9 min on the genome, and mutant pairs containing an intact or mutated tgt allele were obtained after transduction of the tgt locus by P1 bacteriophages into a genetically defined E. coli strain (S. Noguchi, Y. Nishimura, Y. Hirota, and S. Nishimura, J. Biol. Chem. 257:6544-6550, 1982). These tgt mutants grew anerobically with fumarate as an electron acceptor, while nitrate or trimethylamine N-oxide could not be reduced. Furthermore, molybdate reductase activity was almost lacking and the characteristic absorption maxima, corresponding to cytochrome a1 and the cytochrome d complex, were not detectable in low-temperature reduced-minus-oxidized difference spectra in anaerobically grown cells. Transduction of the mutated tgt locus into another E. coli recipient resulted in tgt mutants without anaerobic defects. Transformation of the original tgt mutants with an fnr gene-containing plasmid reversed the anaerobic defects. Clearly, the original tgt mutants harbor a second mutation, affecting the anaerobic regulator protein Fnr. The results suggest that fnr is involved in anaerobic control of components of the cytochrome d complex and of the redox system that transfers electrons to molybdate. F' plasmids containing a fused lacI-lacZ gene with the nonsense codon UAG at different positions in the lacI part were transferred to E. coli strains with a mutated or nonmutated tgt locus but intact in fnr. A twofold increase in the frequency of incorrect readthrough of the UAG codon, dependent on the codon context, was observed in the tgt mutant and is suggested to be caused by a tRNA(Tyr) with G in place of queuosine.
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Affiliation(s)
- B Frey
- Institut für Biochemie, Universität Erlangen-Nürnberg, Federal Republic of Germany
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172
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Coghlan VM, Vickery LE. Expression of human ferredoxin and assembly of the [2Fe-2S] center in Escherichia coli. Proc Natl Acad Sci U S A 1989; 86:835-9. [PMID: 2644647 PMCID: PMC286572 DOI: 10.1073/pnas.86.3.835] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
A cDNA fragment encoding human ferredoxin, a mitochondrial [2Fe-2S] protein, was introduced into Escherichia coli by using an expression vector based on the approach of Nagai and Thøgersen [Nagai, K. & Thøgersen, M. C. (1984) Nature (London) 309, 810-812]. Expression was under control of the lambda PL promoter and resulted in production of ferredoxin as a cleavable fusion protein with an amino-terminal fragment derived from bacteriophage lambda cII protein. The fusion protein was isolated from the soluble fraction of induced cells and was specifically cleaved to yield mature recombinant ferredoxin. The recombinant protein was shown to be identical in size to ferredoxin isolated from human placenta (13,546 Da) by NaDodSO4/PAGE and partial amino acid sequencing. E. coli cells expressing human ferredoxin were brown in color, and absorbance and electron paramagnetic resonance spectra of the purified recombinant protein established that the [2Fe-2S] center was assembled and incorporated into ferredoxin in vivo. Recombinant ferredoxin was active in steroid hydroxylations when reconstituted with cytochromes P-450scc and P-450(11) beta and exhibited rates comparable to those observed for ferredoxin isolated from human placenta. This expression system should be useful in production of native and structurally altered forms of human ferredoxin for studies of ferredoxin structure and function.
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Affiliation(s)
- V M Coghlan
- Department of Biological Chemistry, University of California, Irvine 92717
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173
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Mat-Jan F, Alam KY, Clark DP. Mutants of Escherichia coli deficient in the fermentative lactate dehydrogenase. J Bacteriol 1989; 171:342-8. [PMID: 2644194 PMCID: PMC209593 DOI: 10.1128/jb.171.1.342-348.1989] [Citation(s) in RCA: 127] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Mutants of Escherichia coli deficient in the fermentative NAD-linked lactate dehydrogenase (ldh) have been isolated. These mutants showed no growth defects under anaerobic conditions unless present together with a defect in pyruvate formate lyase (pfl). Double mutants (pfl ldh) were unable to grow anaerobically on glucose or other sugars even when supplemented with acetate, whereas pfl mutants can do so. The ldh mutation was found to map at 30.5 min on the E. coli chromosome. The ldh mutant FMJ39 showed no detectable lactate dehydrogenase activity and produced no lactic acid from glucose under anaerobic conditions as estimated by in vivo nuclear magnetic resonance measurements. We also found that in wild-type strains the fermentative lactate dehydrogenase was conjointly induced by anaerobic conditions and an acidic pH. Despite previous findings that phosphate concentrations affect the proportion of lactic acid produced during fermentation, we were unable to find any intrinsic effect of phosphate on lactate dehydrogenase activity, apart from the buffering effect of this ion.
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Affiliation(s)
- F Mat-Jan
- Department of Microbiology, Southern Illinois University, Carbondale 62901
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174
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Sankar P, Shanmugam KT. Hydrogen metabolism in Escherichia coli: biochemical and genetic evidence for a hydF gene. J Bacteriol 1988; 170:5446-51. [PMID: 3056901 PMCID: PMC211636 DOI: 10.1128/jb.170.12.5446-5451.1988] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
A new gene whose product is essential for production of all three hydrogenase isoenzymes in Escherichia coli has been identified. This gene, termed hydF, mapped at 59 min in the E. coli chromosome and resided next to the hydB gene. The map order of these genes was hydE, hydF, hydB, fhlA, and fdv. The hydF gene was transcribed from its own promoter and coded for a protein with an apparent molecular weight of 43,000 to 44,000. Expression of the hydF operon was enhanced by anaerobic growth conditions. Partial products of the hydF gene were capable of supporting various levels of hydrogenase activity in a hydF mutant in the presence of the fhlA gene product, also produced from multicopy plasmids. In the presence of a second mutation in an unidentified, unlinked gene, hydrogenase activity in a hydF mutant was restored by plasmids which carried incomplete hydF and hydB+ genes. These results suggest that the products of hydF and fhlA interact with each other and with yet one other gene product.
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Affiliation(s)
- P Sankar
- Department of Microbiology and Cell Science, University of Florida, Gainesville 32611
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175
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Abstract
Synthesis of formate dehydrogenase coupled to formate hydrogenlyase activity in Escherichia coli was found to require the product of the fhlA gene. Transcription of fdhF, the gene coding for the 80-kilodalton (kDa) selenopeptide of formate dehydrogenase, was not detected in an fhlA genetic background. Mutations in the fhlA gene also abolished production of the hydrogenase activity associated with formate hydrogenlyase activity. The fhlA gene resides next to the hydB gene at 59 min in the E. coli chromosome, and the two genes are transcribed in opposite directions. The fhlA gene codes for a 78-kDa protein. A neighboring gene, fdv, codes for an 82-kDa protein, and the physiological role of this gene product is unknown, although a role in H2 metabolism can be detected.
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Affiliation(s)
- P Sankar
- Department of Microbiology and Cell Science, University of Florida, Gainesville 32611
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176
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Milner JL, Grothe S, Wood JM. Proline porter II is activated by a hyperosmotic shift in both whole cells and membrane vesicles of Escherichia coli K12. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(18)68123-2] [Citation(s) in RCA: 91] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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177
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Johnson MK, Kowal AT, Morningstar JE, Oliver ME, Whittaker K, Gunsalus RP, Ackrell BA, Cecchini G. Subunit location of the iron-sulfur clusters in fumarate reductase from Escherichia coli. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(18)68098-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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178
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Nohno T, Kasai Y, Saito T. Cloning and sequencing of the Escherichia coli chlEN operon involved in molybdopterin biosynthesis. J Bacteriol 1988; 170:4097-102. [PMID: 3045084 PMCID: PMC211414 DOI: 10.1128/jb.170.9.4097-4102.1988] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The nucleotide sequence of a HinPI-HpaII restriction nuclease fragment which complemented a delta chlE strain of Escherichia coli was determined. Two open reading frames were deduced to be the structural genes for ChlE and ChlN proteins, which have molecular weights of 44,067 and 26,719, respectively. Both proteins were required for complementing a chromosomal deletion of the chlE locus. The chlE and chlN genes were transcribed from a common promoter, chlEp, located upstream of chlE. Transcriptional and translational signal sequences were recognized in this region.
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Affiliation(s)
- T Nohno
- Department of Pharmacology, Kawasaki Medical School, Kurashiki, Japan
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179
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Location of sequences in the nar promoter of Escherichia coli required for regulation by Fnr and NarL. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(18)68297-3] [Citation(s) in RCA: 62] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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180
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181
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Cole ST, Eiglmeier K, Ahmed S, Honore N, Elmes L, Anderson WF, Weiner JH. Nucleotide sequence and gene-polypeptide relationships of the glpABC operon encoding the anaerobic sn-glycerol-3-phosphate dehydrogenase of Escherichia coli K-12. J Bacteriol 1988; 170:2448-56. [PMID: 3286606 PMCID: PMC211154 DOI: 10.1128/jb.170.6.2448-2456.1988] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The nucleotide sequence of a 4.8-kilobase SacII-PstI fragment encoding the anaerobic glycerol-3-phosphate dehydrogenase operon of Escherichia coli has been determined. The operon consists of three open reading frames, glpABC, encoding polypeptides of molecular weight 62,000, 43,000, and 44,000, respectively. The 62,000- and 43,000-dalton subunits corresponded to the catalytic GlpAB dimer. The larger GlpA subunit contained a putative flavin adenine dinucleotide-binding site, and the smaller GlpB subunit contained a possible flavin mononucleotide-binding domain. The GlpC subunit contained two cysteine clusters typical of iron-sulfur-binding domains. This subunit was tightly associated with the envelope fraction and may function as the membrane anchor for the GlpAB dimer. Analysis of the GlpC primary structure indicated that the protein lacked extended hydrophobic sequences with the potential to form alpha-helices but did contain several long segments capable of forming transmembrane amphipathic helices.
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Affiliation(s)
- S T Cole
- Biochimie des Régulations Cellulaires, Institut Pasteur, Paris, France
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182
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in't Veld G, Mannion B, Weiss J, Elsbach P. Effects of the bactericidal/permeability-increasing protein of polymorphonuclear leukocytes on isolated bacterial cytoplasmic membrane vesicles. Infect Immun 1988; 56:1203-8. [PMID: 3281903 PMCID: PMC259784 DOI: 10.1128/iai.56.5.1203-1208.1988] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The bactericidal/permeability-increasing protein (BPI) of polymorphonuclear leukocytes is a potent bactericidal agent specific for gram-negative bacteria. The protein blocks bacterial multiplication without substantially inhibiting the uptake and incorporation of macromolecular precursors, suggesting that the cytoplasmic membrane escapes early injury. Because greater than 90% of bound BPI can be removed from the bacterial surface sites after irreversible loss of viability, it was uncertain whether BPI reaches the cytoplasmic membrane and, if so, affects its functions. This study shows that BPI caused similar dose-dependent inhibition of O2 consumption and metabolic energy-dependent amino acid transport by cytoplasmic membrane vesicles of both gram-negative (Escherichia coli) and gram-positive (Bacillus subtilis) bacteria. Near maximal inhibition occurred at BPI doses that caused complete killing of an equivalent number of intact E. coli, with binding of BPI to membrane vesicles that was less than or equal to 10% of binding to intact (BPI-sensitive) bacteria. The effects of BPI and of the membrane-disruptive peptide antibiotic polymyxin B on membrane vesicles were distinctly different, indicating that the two agents affect membrane function by different mechanisms. BPI also rapidly inhibited O2 consumption by intact E. coli, with minimal impairment of bacterial protein synthesis. Thus, BPI is capable of damaging the cytoplasmic membrane of both gram-negative and gram-positive bacteria and of inhibiting at least one cytoplasmic membrane-associated function in intact E. coli. The relationship between these effects and the mechanism of bacterial killing by BPI remains to be established.
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Affiliation(s)
- G in't Veld
- Department of Medicine, New York University Medical Center, New York 10016
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183
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Trypsin proteolysis of the cytochrome d complex of Escherichia coli selectively inhibits ubiquinol oxidase activity while not affecting N,N,N',N'-tetramethyl-p-phenylenediamine oxidase activity. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(18)60711-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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184
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Bilous PT, Weiner JH. Molecular cloning and expression of the Escherichia coli dimethyl sulfoxide reductase operon. J Bacteriol 1988; 170:1511-8. [PMID: 2832366 PMCID: PMC210995 DOI: 10.1128/jb.170.4.1511-1518.1988] [Citation(s) in RCA: 65] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The dimethyl sulfoxide (DMSO) reductase operon coding for a membrane-bound iron-sulfur, molybdoenzyme, which functions as a terminal reductase in Escherichia coli, has been isolated and cloned from an E. coli gene bank. Two clones, MV12(pLC19-36) and MV12(pLC43-43), overexpressed both DMSO and trimethylamine N-oxide (TMAO) reductase activities 13- to 15-fold compared with wild-type cells. Amplification was highest in cells grown anaerobically on fumarate, while cells grown on DMSO or TMAO displayed reduced levels of enzyme amplification. Growth on nitrate or aerobic growth repressed expression of the enzyme. A 6.5-kilobase-pair DNA restriction endonuclease fragment was subcloned from pLC19-36 into the vector pBR322, yielding a recombinant DMSO reductase plasmid, pDMS159. Two polypeptides were amplified and identified on sodium dodecyl sulfate-polyacrylamide gels of proteins from E. coli HB101 harboring pDMS159: a membrane-bound protein with molecular weight 82,600 and a soluble polypeptide with molecular weight 23,600. Three plasmid-encoded polypeptides with molecular weights of 87,500, 23,300, and 22,600 were detected by in vivo transcription/translation studies. The smallest subunit was poorly defined and not detectable by Coomassie blue staining. The DMSO reductase operon was localized to the 20.0-min position on the E. coli linkage map.
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Affiliation(s)
- P T Bilous
- Department of Biochemistry, University of Alberta, Edmonton, Canada
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185
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Sodergren EJ, DeMoss JA. narI region of the Escherichia coli nitrate reductase (nar) operon contains two genes. J Bacteriol 1988; 170:1721-9. [PMID: 2832376 PMCID: PMC211023 DOI: 10.1128/jb.170.4.1721-1729.1988] [Citation(s) in RCA: 67] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
In previous studies it has been established that in Escherichia coli the three known subunits of anaerobic nitrate reductase are encoded by the narGHI operon. From the nucleotide sequence of the narI region of the operon we conclude that, in addition to the narG and narH genes, the nar operon contains two other open reading frames (ORFs), ORF1 and ORF2, that encode proteins of 26.5 and 25.5 kilodaltons, respectively. Protein fusions to each of the genes in the operon showed that expression of all four genes was similarly regulated. The reading frames of ORF1 and ORF2 were verified, and the N-terminal sequence for the ORF1 fusion protein was determined. The nar operon therefore contains four genes designated and ordered as narGHJI.
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Affiliation(s)
- E J Sodergren
- Department of Biochemistry and Molecular Biology, University of Texas Medical School, Houston 77025
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186
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Weiner JH, MacIsaac DP, Bishop RE, Bilous PT. Purification and properties of Escherichia coli dimethyl sulfoxide reductase, an iron-sulfur molybdoenzyme with broad substrate specificity. J Bacteriol 1988; 170:1505-10. [PMID: 3280546 PMCID: PMC210994 DOI: 10.1128/jb.170.4.1505-1510.1988] [Citation(s) in RCA: 118] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Dimethyl sulfoxide reductase, a terminal electron transfer enzyme, was purified from anaerobically grown Escherichia coli harboring a plasmid which codes for dimethyl sulfoxide reductase. The enzyme was purified to greater than 90% homogeneity from cell envelopes by a three-step purification procedure involving extraction with the detergent Triton X-100, chromatofocusing, and DEAE ion-exchange chromatography. The purified enzyme was composed of three subunits with molecular weights of 82,600, 23,600, and 22,700 as identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The native molecular weight was determined by gel electrophoresis to be 155,000. The purified enzyme contained 7.5 atoms of iron and 0.34 atom of molybdenum per mol of enzyme. The presence of molybdopterin cofactor in dimethyl sulfoxide reductase was identified by reconstitution of cofactor-deficient NADPH nitrate reductase activity from Neurospora crassa nit-I mutant and by UV absorption and fluorescence emission spectra. The enzyme displayed a very broad substrate specificity, reducing various N-oxide and sulfoxide compounds as well as chlorate and hydroxylamine.
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Affiliation(s)
- J H Weiner
- Department of Biochemistry, University of Alberta, Edmonton, Canada
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187
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Darling TN, Blum JJ. D-lactate production by Leishmania braziliensis through the glyoxalase pathway. Mol Biochem Parasitol 1988; 28:121-7. [PMID: 3130573 DOI: 10.1016/0166-6851(88)90059-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Leishmania braziliensis promastigotes incubated anaerobically produce D-lactate from glucose, ribose, and methylglyoxal, but not from glycerol, alanine, or pyruvate, suggesting the presence of glyoxalases I and II but the absence of D-lactate dehydrogenase. Further support for this is shown by: (1) conversion of methylglyoxal to D-lactate in sonicates of promastigotes in the presence of reduced glutathione, (2) utilization of phenylglyoxal at rates comparable to methylglyoxal, (3) lack of utilization of exogenously supplied D-lactate by promastigotes under aerobic conditions. Sonicates of promastigotes catalyze the conversion of dihydroxyacetone phosphate to methylglyoxal, suggesting the presence of methylglyoxal synthase. Whereas the rate of production of D-lactate from glucose is much greater under anaerobic conditions, the rate from methylglyoxal is independent of oxygen tension, indicating that control of flux through the methylglyoxal pathway occurs at, or before, methylglyoxal synthase.
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Affiliation(s)
- T N Darling
- Dept. of Physiology, Duke University Medical Center, Durham, NC 27710
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188
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Inductions of superoxide dismutases in Escherichia coli under anaerobic conditions. Accumulation of an inactive form of the manganese enzyme. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(18)68921-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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189
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Stoker K, Oltmann LF, Stouthamer AH. Partial characterization of an electrophoretically labile hydrogenase activity of Escherichia coli K-12. J Bacteriol 1988; 170:1220-6. [PMID: 3277948 PMCID: PMC210895 DOI: 10.1128/jb.170.3.1220-1226.1988] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
A mutant of Escherichia coli K-12 is described that is specifically impaired in only one hydrogenase isoenzyme. By means of Tn5-mediated insertional mutagenesis, a class of mutants was isolated (class I) that had retained 20% of the overall hydrogenase activity. As determined by neutral polyacrylamide gel electrophoresis, the mutant contained normal amounts of the hydrogenase isoenzymes 1 and 2. Therefore, the hydrogenase activity affected seemed to be electrophoretically labile and was called hydrogenase L. The presence of such an activity was recently suggested in various papers and was called isoenzyme 3. Hydrogenase L might be identical or part of the latter isoenzyme. By DEAE ion-exchange chromatography it could be separated from hydrogenases 1 and 2. Hydrogenase activity in the parent strain HB101, determined manometrically with cell-free preparations and methylviologen as the electron acceptor, immediately showed maximal activity. However, class I mutants showed a lag phase which was dependent on the protein concentration utilized in the assay. This suggested that the fast initial activity of HB101 was due to hydrogenase L. The enzyme or enzyme complex showed an Mr around 300,000 and a pH optimum between 7 and 8. Strong indications about its physiological role were provided by the finding that in class I mutants H2 production by the formate-hydrogen lyase pathway was unimpaired, whereas fumarate-dependent H2 uptake was essentially zero. Complementation with F-prime factor F'116 but not with F'143 and coconjugation and cotransduction experiments localized the mutation (hydL) close to metC at approximately 64.8 min.
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Affiliation(s)
- K Stoker
- Department of Microbiology, Vrije Universiteit, Amsterdam, The Netherlands
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190
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Abstract
To study the regulation of the expression in Escherichia coli of the ubiG gene, which codes for the last enzyme in the pathway of ubiquinone biosynthesis, a fusion between the ubiG and lacZ genes was constructed in vitro. The results showed that (i) the expression of the ubiG gene was higher under aerobic conditions than under anaerobic growth conditions, (ii) the presence of glucose in the culture medium decreased the transcription of the ubiG gene, and (iii) cya and crp mutants exhibited lower levels of ubiG gene expression than the wild-type strain. The addition of cyclic AMP increased the expression of the ubiG gene in both cya and wild-type strains but not in a crp mutant. This fact suggests that the cyclic AMP receptor protein-cyclic AMP complex positively modulates ubiG gene transcription. It was also determined that the transcription of the ubiG gene was in the counterclockwise direction on the E. coli map.
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Affiliation(s)
- I Gibert
- Department of Genetics and Microbiology, Autonomous University of Barcelona, Bellaterra, Spain
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191
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Martin W, Smith JA, Lewis MJ, Henderson AH. Evidence that inhibitory factor extracted from bovine retractor penis is nitrite, whose acid-activated derivative is stabilized nitric oxide. Br J Pharmacol 1988; 93:579-86. [PMID: 2897219 PMCID: PMC1853840 DOI: 10.1111/j.1476-5381.1988.tb10313.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
1. Unactivated extracts of bovine retractor penis (BRP) contains 3-7 microM nitrite. Acid-activation of these extracts at pH 2 for 10 min followed by neutralization generates the active form of inhibitory factor (IF; assayed by its vasodilator action on rabbit aorta), and is associated with partial loss of nitrite. 2. Increasing the time of acid-activation at pH 2 from 10 to 60 min with intermittent vortex mixing generates greater vasodilator activity and increases nitrite loss. 3. When acid-activated and neutralized extracts are incubated at 37 degrees C or 30 min or boiled for 5 min, vasodilator activity is lost and nitrite content increased. Reactivation of these samples at pH 2 for 10 min followed by neutralization leads to partial recoveries of vasodilator activity with loss in nitrite content. 4. Addition of sodium nitrite to BRP extracts increases acid-activatable vasodilator activity pro rata. 5. Acid-activation of aqueous sodium nitrite solutions results in less loss of nitrite and generation of less vasodilator activity than BRP extracts. Vasodilatation is only transient and is rapidly abolished on neutralization, whereas responses to acid-activated BRP extracts are more prolonged and activity is stable on ice. 6. Bovine aortic endothelial cells yield vasodilator activity that is indistinguishable from that isolated from BRP. It is activated by acid, stable on ice, abolished by boiling or by haemoglobin, and appears to be due to the generation of nitric oxide (NO) from nitrite. 7. The data provide confirmatory evidence that nitrite in BRP extracts is IF, that acid-activation of BRP extracts yields NO which is responsible for its vasodilator action, and that inactivation occurs by decay of NO to nitrite and nitrate. They further suggest that BRP extracts contain a NO-stabilizing agent which favours conversion of nitrite to NO. 8. The finding that bovine aortic endothelial cells yield an agent indistinguishable from IF suggests that nitrite in endothelial cells may likewise be the precursor of endothelium-derived relaxing factor (EDRF), itself identified as NO.
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Affiliation(s)
- W Martin
- Department of Cardiology, University of Wales College of Medicine, Heath Park, Cardiff
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192
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Sedgwick EG, Bragg PD. The fluorescence intensity of the lipophilic probe N-phenyl-1-naphthylamine responds to the oxidation-reduction state of purified Escherichia coli cytochrome o incorporated into phospholipid vesicles. FEBS Lett 1988; 229:127-30. [PMID: 3278931 DOI: 10.1016/0014-5793(88)80811-1] [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: 01/05/2023]
Abstract
N-Phenyl-1-naphthylamine (NPN), a reagent which has been used previously to probe the fluidity or microviscosity of the membrane lipids of intact cells of Escherichia coli, was found to respond to the redox state of purified cytochrome o incorporated into lipid vesicles formed from purified or E. coli phospholipids. NPN was bound to the proteoliposomes to produce a steady-state level of fluorescence intensity. Addition of the substrate ascorbate, in the presence of phenazine methosulfate as an electron donor, did not alter the fluorescence. However, following complete removal of oxygen from the medium by oxidation of the substrate by molecular oxygen catalyzed by cytochrome o, there was an increase in the fluorescence of NPN. This coincided with the reduction of cytochrome o. Reoxidation of the cytochrome by addition of oxygen decreased the fluorescence to steady-state levels until the oxidant had been completely reduced. The fluorescence changes were dependent on the incorporation of cytochrome o into phospholipid vesicles but were insensitive to the state of energization of the vesicle membrane.
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Affiliation(s)
- E G Sedgwick
- Department of Biochemistry, University of British Columbia, Vancouver, Canada
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193
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Kalman LV, Gunsalus RP. The frdR gene of Escherichia coli globally regulates several operons involved in anaerobic growth in response to nitrate. J Bacteriol 1988; 170:623-9. [PMID: 3276662 PMCID: PMC210700 DOI: 10.1128/jb.170.2.623-629.1988] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Fumarate reductase catalyzes the terminal step of anaerobic electron transport with fumarate as a terminal electron acceptor. Transcription of the fumarate reductase (frdABCD) operon in Escherichia coli is repressed in the presence of the preferred terminal electron acceptors, oxygen and nitrate. To identify trans-acting genes involved in regulation by nitrate, a number of E. coli mutants were generated in which expression of a frdA'-'lacZ protein fusion was no longer fully repressed by nitrate. One of these mutants, strain LK23R35, exhibited 17-fold higher beta-galactosidase activity than the wild-type strain when grown anaerobically in the presence of nitrate. When grown aerobically in the presence of nitrate, it contained three- to fourfold more beta-galactosidase activity than the wild-type strain did. Oxygen regulation of frd expression, however, was unaffected by the mutation, since the level of beta-galactosidase activity in both strains was nearly identical when they were grown in the absence of nitrate either aerobically or anaerobically. To confirm that the mutation acts in trans to frdABCD, we measured fumarate reductase levels and found them to parallel FrdA'-beta-galactosidase activity under all growth conditions tested. The effect of the mutation is pleiotropic, since the levels of nitrate reductase in LK23R35 were not induced by the addition of nitrate. The frdR mutant was also derepressed for nitrate control of the trimethylamine-N-oxide reductase and alcohol dehydrogenase enzymes. The mutation maps in a region between trp and hemA at 27 min on the E. coli chromosome. This gene, where we call frdR, is involved in both positive and negative regulation of electron transport and fermentation associated genes. A cloned 4.9-kilobase fragment of chromosomal DNA was found to complement the frdR mutation; both repression of fumarate reductase gene expression and activation of nitrate reductase gene expression were restored.
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Affiliation(s)
- L V Kalman
- Department of Microbiology, University of California, Los Angeles 90024
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194
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Georgiou CD, Dueweke TJ, Gennis RB. Regulation of expression of the cytochrome d terminal oxidase in Escherichia coli is transcriptional. J Bacteriol 1988; 170:961-6. [PMID: 2828338 PMCID: PMC210748 DOI: 10.1128/jb.170.2.961-966.1988] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The cytochrome d complex is one of the two terminal oxidases in the aerobic respiratory system of Escherichia coli. This enzyme is not present in cells grown with high levels of dissolved oxygen in the culture medium but accumulates after mid-exponential growth, reaching high levels in stationary-phase cells. In this study, the transcriptional activity of the cyd operon, encoding the two subunits of the enzyme, was examined under a variety of growth conditions. This was accomplished by the use of a chromosomal operon fusion, cyd-lacZ, generated in vivo by a lambda plac-Mu hopper bacteriophage and also by the use of a cyd-lacZ protein fusion created in vitro on a plasmid, transferred onto a lambda transducing phage, and examined as a single-copy lysogen. Transcription of the gene fusions was monitored by determination of beta-galactosidase activity. The data clearly show that cyd is transcriptionally regulated and that induction is observed when the culture reaches a sufficient cell density so as to substantially reduce the steady-state levels of dissolved oxygen. The transcriptional activity is also regulated by other growth conditions, including the carbon source. The turn-on of cyd under semianaerobic conditions does not require the fnr gene product, cyclic AMP, or the cyclic AMP-binding protein.
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Affiliation(s)
- C D Georgiou
- Department of Biochemistry, University of Illinois, Urbana 61801
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195
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Axley MJ, Stadtman TC. Anaerobic induction of Escherichia coli formate dehydrogenase (hydrogenase-linked) is enhanced by gyrase inactivation. Proc Natl Acad Sci U S A 1988; 85:1023-7. [PMID: 2829213 PMCID: PMC279693 DOI: 10.1073/pnas.85.4.1023] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Escherichia coli synthesizes a hydrogenase-linked formate dehydrogenase (FDHH) under anaerobic conditions in the absence of nitrate. In striking contrast to many other anaerobic-specific genes, which require DNA to be negatively supercoiled for expression, we have found that inhibition of DNA gyrase activity enhances expression from the gene (fdhF) encoding the selenopolypeptide of FDHH. Fusions of the 5' flanking region of fdhF and the structural gene of lacZ were used to determine fdhF expression under varying conditions. Chemical inhibitors and a temperature-sensitive mutant allowed in vivo inhibition of gyrase activity. In each case, concomitant with gyrase inhibition there was a substantial increase in the induction of fusion protein synthesis. This enhancement of expression is observed for the intact fdhF gene residing on the chromosome as well as the fusion gene in a multicopy plasmid. Inhibition of gyrase activity will partially overcome the inhibition of fdhF expression due to nitrate but does not allow fusion protein synthesis in the presence of oxygen.
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Affiliation(s)
- M J Axley
- Laboratory of Biochemistry, National Heart, Lung, and Blood Institute, Bethesda, MD 20892
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196
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Effect of hematin on the activities of nitrite reductase and catalase in lactobacilli. Arch Microbiol 1988. [DOI: 10.1007/bf00422008] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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197
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Ralt D, Wishnok JS, Fitts R, Tannenbaum SR. Bacterial catalysis of nitrosation: involvement of the nar operon of Escherichia coli. J Bacteriol 1988; 170:359-64. [PMID: 3275620 PMCID: PMC210650 DOI: 10.1128/jb.170.1.359-364.1988] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
We have developed a rapid and sensitive fluorimetric method, based on the formation of a fluorescent product from nitrosation of 2,3-diaminonaphthalene, for measuring the ability of bacteria to catalyze nitrosation of amines. We have shown in Escherichia coli that nitrosation can be induced under anaerobic conditions by nitrite and nitrate, that formate is the most efficient electron donor for this reaction, and that nitrosation may be catalyzed by nitrate reductase (EC 1.7.99.4). The narG mutants defective in nitrate reductase do not catalyze nitrosation, and the fnr gene is essential for nitrosation. Induction by nitrite or nitrate of nitrosation, N2O production, and nitrate reductase activity all require the narL gene.
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Affiliation(s)
- D Ralt
- Department of Applied Biological Sciences, Massachusetts Institute of Technology, Cambridge 02139
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198
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Hassan HM, Moody CS. Regulation of manganese-containing superoxide dismutase in Escherichia coli. Anaerobic induction by nitrate. J Biol Chem 1987. [DOI: 10.1016/s0021-9258(18)45506-8] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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199
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Bradley SA, Tinsley CR, Muiry JA, Henderson PJ. Proton-linked L-fucose transport in Escherichia coli. Biochem J 1987; 248:495-500. [PMID: 2829831 PMCID: PMC1148569 DOI: 10.1042/bj2480495] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
1. Addition of L-fucose to energy-depleted anaerobic suspensions of Escherichia coli elicited an uncoupler-sensitive alkaline pH change diagnostic of L-fucose/H+ symport activity. 2. L-Galactose or D-arabinose were also substrates, but not inducers, for the L-fucose/H+ symporter. 3. L-Fucose transport into subcellular vesicles was dependent upon respiration, displayed a pH optimum of about 5.5, and was inhibited by protonophores and ionophores. 4. These results showed that L-fucose transport into E. coli was energized by the transmembrane electrochemical gradient of protons. 5. Neither steady state kinetic measurements nor assays of L-fucose binding to periplasmic proteins revealed the existence of a second L-fucose transport system.
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Affiliation(s)
- S A Bradley
- Department of Biochemistry, University of Cambridge, U.K
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200
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Abstract
Fifteen oxygen-sensitive (Oxys) mutants of Escherichia coli were isolated after exposure to UV light. The mutants did not form macroscopic colonies when plated aerobically. They did form macroscopic colonies anaerobically. Oxygen, introduced during log phase, inhibited the growth of liquid cultures. The degree of inhibition was used to separate the mutants into three classes. Class I mutants did not grow after exposure to oxygen. Class II mutants were able to grow, but at a reduced rate and to a reduced final titer, when compared with the wild-type parent. Class III mutants formed filaments in response to oxygen. Genetic experiments indicated that the mutations map to six different chromosomal regions. The results of enzymatic assays indicated that 7 of the 10 class I mutants have low levels of catalase, peroxidase, superoxide dismutase, and respiratory enzymes when compared with the wild-type parent. Mutations in five of the seven class I mutants which have the low enzyme activities mapped within the region 8 to 13.5 min. P1 transduction data indicated that mutations in three of these five mutants, Oxys-6, Oxys-14, and Oxys-17, mapped to 8.4 min. The correlation of low enzyme levels and mapping data suggests that a single gene may regulate several enzymes in response to oxygen. The remaining three class I mutants had wild-type levels of catalase, peroxidase, and superoxide dismutase, but decreased respiratory activity. The class II and III mutants had enzyme activities similar to those of the wild-type parent. Our results demonstrate that mutations in at least six genes can be expressed as oxygen sensitivity. Some of these genes may be involved in respiration or cell division or may regulate the expression of several enzymes.
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Affiliation(s)
- C S Jamison
- Oak Ridge Graduate School of Biomedical Sciences, University of Tennessee 37831
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