A Salmonella typhimurium genetic locus which confers copper tolerance on copper-sensitive mutants of Escherichia coli

Gupta, Sita D.; Wu, Henry C.; Rick, Paul D.

doi:10.1128/jb.179.16.4977-4984.1997

Cited by 70 publications

(80 citation statements)

References 38 publications

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“…The pI was 9.25. The deduced CcdA exhibited an identity of 55% to proteins involved in cytochrome c biogenesis of R. capsulatus (14) or 32% to a protein involved in sporulation of B. subtilis (46) or in heavy metal resistance of different gramnegative bacteria (22,47), while an identity of 42% was observed to the ORF2 gene product of the sox gene cluster of P. pantotrophus (data not shown). Therefore, the CcdA protein was analyzed in detail.…”

Section: Resultsmentioning

confidence: 95%

“…CcdA of P. pantotrophus is homologous to proteins of other bacteria involved in copper tolerance (17,22), mercury resistance (47), spore synthesis (46), and cytochrome c biogenesis (13,35,45). CcdA was not cotranscribed with a thioredoxin in P. pantotrophus, and it missed the thioredoxin stretch at the C terminus as described for DipZ homologous proteins found in E. coli (13) or P. aeruginosa (35).…”

Section: Discussionmentioning

confidence: 99%

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Identification of ccdA in Paracoccus pantotrophus GB17: Disruption of ccdA Causes Complete Deficiency in c -Type Cytochromes

Bardischewsky

Friedrich

2001

J Bacteriol

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A transposon Tn5-mob insertional mutant of Paracoccus pantotrophus GB17, strain TP43, was unable to oxidize thiosulfate aerobically or to reduce nitrite anaerobically, and the cellular yields were generally decreased by 11 to 20%. Strain TP43 was unable to form functional c-type cytochromes, as determined by difference spectroscopy and heme staining. However, formation of apocytochromes and their transport to the periplasm were not affected, as seen with SoxD, a c-type cytochrome associated with the periplasmic sulfite dehydrogenase homologue. The Tn5-mob-containing DNA region of strain TP43 was cloned into pSUP205 to produce pE18TP43. With the aid of pE18TP43 the corresponding wild-type gene region of 15 kb was isolated from a heterogenote recombinant to produce pEF15. Sequence analysis of 2.8 kb of the relevant region uncovered three open reading frames, designated ORFA, ccdA, and ORFB, with the latter being oriented divergently. ORFA and ccdA were constitutively cotranscribed as determined by primer extension analysis. In strain TP43 Tn5-mob was inserted into ccdA. The deduced ORFA product showed no similarity to any protein in databases. However, the ccdA gene product exhibited similarities to proteins assigned to different functions in bacteria, such as cytochrome c biogenesis. For these proteins at least six transmembrane helices are predicted with the potential to form a channel with two conserved cysteines. This structural identity suggests that these proteins transfer reducing equivalents from the cytoplasm to the periplasm and that the cysteines bring about this transfer to enable the various specific functions via specific redox mediators such as thioredoxins. CcdA of P. pantotrophus is 42% identical to a protein predicted by ORF2, and its location within the sox gene cluster coding for lithotrophic sulfur oxidation suggested a different function.The neutrophilic facultatively lithoautotrophic gram-negative bacterium Paracoccus pantotrophus grows aerobically with a large variety of carbon sources and with molecular hydrogen or thiosulfate as energy source, and nitrate serves as electron acceptor under anaerobic conditions (41). P. pantotrophus (formerly Paracoccus denitrificans and Thiosphaera pantotropha [31,38,41]) has a branched electron transfer network. The electron flux is regulated by the reduction of the Q pool (33). While the transfer of electrons by the terminal cytochrome oxidases aa 3 and cbb 3 results in a translocation of six protons (6H ϩ /2e Ϫ ) (36, 54), the reduction of a terminal electron acceptor by the quinol oxidase o results in a translocation of only four protons (4H ϩ /2e Ϫ ) (39). To identify the components involved in energy transformation by oxidation of reduced inorganic sulfur compounds (Sox) of P. pantotrophus GB17, genetic studies were initiated by the isolation of mutants. Transpositional mutagenesis with Tn5-

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Section: Resultsmentioning

confidence: 95%

Section: Discussionmentioning

confidence: 99%

Identification of ccdA in Paracoccus pantotrophus GB17: Disruption of ccdA Causes Complete Deficiency in c -Type Cytochromes

Bardischewsky

Friedrich

2001

J Bacteriol

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“…Recently, Fuller et al (16) found that mutation of dsbB, also involved in disulfide bond formation, caused attenuation of virulence in P. multocida in a septicemic mouse model. Additionally, DsbD is required for c-type cytochrome biogenesis under anaerobic conditions and plays a role in copper (Cu 2ϩ ) tolerance in bacteria such as E. coli, S. enterica serovar Typhimurium, and P. aeruginosa (11,21,42). Other genes involved in Cu 2ϩ homeostasis have been identified, using IVET systems, from S. enterica serovar Typhimurium (24) and Staphylococcus aureus (34).…”

Section: Discussionmentioning

confidence: 99%

In Vivo-Expressed Genes ofPasteurella multocida

et al. 2001

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Pasteurella multocida is the causative agent of infectious diseases of economic importance such as fowl cholera, bovine hemorrhagic septicemia, and porcine atrophic rhinitis. However, knowledge of the molecular mechanisms and determinants that P. multocida requires for virulence and pathogenicity is still limited. To address this issue, we developed a genetic expression system, based on the in vivo expression technology approach first described by Mahan et al. (Science 259:686-688, 1993), to identify in vivo-expressed genes of P. multocida. Numerous genes, such as those encoding outer membrane lipoproteins, metabolic and biosynthetic enzymes, and a number of hypothetical proteins, were identified. These may prove to be useful targets for attenuating mutation and/or warrant further investigation for their roles in immunity and/or pathogenesis.Pasteurella multocida is an opportunistic veterinary and human pathogen with worldwide distribution. Certain serotypes are the etiologic agents of severe types of pasteurellosis, such as fowl cholera in avian species, hemorrhagic septicemia in cattle and buffalo, and atrophic rhinitis in swine. Despite considerable research into the mechanisms of immunity, virulence, and pathogenesis, safe and effective vaccines against pasteurellosis are still lacking and little is known of the molecular mechanisms of pathogenesis.Mahan et al. (35) first described a system to identify in vivo-expressed genes and termed this "in vivo expression technology" (IVET). Various IVET systems have since been designed and used in a number of different organisms (reviewed in references 9, 24, and 25). Information gained from these research efforts has identified a number of known virulence factors, metabolic and biosynthetic genes, and, interestingly, many genes with no known function. IVET systems provide an insight into the genes which are required for survival and multiplication in vivo, and the gene products identified may represent new targets for attenuating mutations, antimicrobial agents, or recombinant vaccines. The inactivation of genes identified by IVET systems has, in many cases, resulted in the attenuation of virulence, indicating an important role for these in vivo-expressed genes in pathogenesis (34,52). In addition, the in vivo promoters themselves could be utilized for heterologous antigen expression in vivo.Outer membrane protein preparations from in vivo-grown P. multocida cells protect birds from heterologous serotypes, whereas in vitro-grown bacteria provide protection only against the homologous somatic serotype (17,22,23). The in vivo-expressed antigens involved in providing heterologous protection have been termed the cross-protective factors. Much interest has been focused on identifying the cross-protective factors of P. multocida fowl cholera strains, yet none has been isolated and characterized to date. The IVET system provides a new approach for identifying such genes and overcomes the limitations of using in vitro media and conditions to mimic the host factors responsibl...

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“…5). Downstream of the T6SS cluster are three putative genes encoding increased copper tolerance, including dsbG (24). The regions flanking the T6SS gene cluster on pESA3 are conserved on pCTU1; however, the 16,937-bp T6SS locus is replaced by a specific 32-bp sequence (Fig.…”

Section: Fig 1 Sequence Alignment Of Pesa3 and Pctu1 Produced Withmentioning

confidence: 99%

Characterization of Putative Virulence Genes on the Related RepFIB Plasmids Harbored by Cronobacter spp

Franco

Grim

et al. 2011

Appl Environ Microbiol

149

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Cronobacter spp. are emerging neonatal pathogens that cause meningitis, sepsis, and necrotizing enterocolitis. The genus Chronobacter consists of six species: C. sakazakii, C. malonaticus, C. muytjensii, C. turicensis, C. dublinensis, and Cronobacter genomospecies group 1. Whole-genome sequencing of C. sakazakii BAA-894 and C. turicensis z3032 revealed that they harbor similarly sized plasmids identified as pESA3 (131 kb) and pCTU1 (138 kb), respectively. In silico analysis showed that both plasmids encode a single RepFIB-like origin of replication gene, repA, as well as two iron acquisition systems (eitCBAD and iucABCD/iutA). In a chrome azurol S agar diffusion assay, it was demonstrated that siderophore activity was associated with the presence of pESA3 or pCTU1. Additionally, pESA3 contains a cpa (Cronobacter plasminogen activator) gene and a 17-kb type 6 secretion system (T6SS) locus, while pCTU1 contains a 27-kb region encoding a filamentous hemagglutinin gene (fhaB), its specifc transporter gene (fhaC), and associated putative adhesins (FHA locus), suggesting that these are virulence plasmids. In a repA-targeted PCR assay, 97% of 229 Cronobacter species isolates were found to possess a homologous RepFIB plasmid. All repA PCR-positive strains were also positive for the eitCBAD and iucABCD/iutA iron acquisition systems. However, the presence of cpa, T6SS, and FHA loci depended on species, demonstrating a strong correlation with the presence of virulence traits, plasmid type, and species. These results support the hypothesis that these plasmids have evolved from a single archetypical plasmid backbone through the cointegration, or deletion, of specific virulence traits in each species. Farmer et al. (20) established the taxonomic position of Enterobacter sakazakii, which was previously identified as yellow-pigmented Enterobacter cloacae based on DNA-DNA hybridization studies in combination with phenotypic

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A Salmonella typhimurium genetic locus which confers copper tolerance on copper-sensitive mutants of Escherichia coli

Cited by 70 publications

References 38 publications

Identification of ccdA in Paracoccus pantotrophus GB17: Disruption of ccdA Causes Complete Deficiency in c -Type Cytochromes

Identification of ccdA in Paracoccus pantotrophus GB17: Disruption of ccdA Causes Complete Deficiency in c -Type Cytochromes

In Vivo-Expressed Genes ofPasteurella multocida

Characterization of Putative Virulence Genes on the Related RepFIB Plasmids Harbored by Cronobacter spp

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