The tcrB gene is part of the tcrYAZB operon conferring copper resistance in Enterococcus faecium and Enterococcus faecalis

Microbiology ◽  
2005 ◽  
Vol 151 (9) ◽  
pp. 3019-3025 ◽  
Author(s):  
Henrik Hasman
Keyword(s):  
Binding Sites ◽  
Enterococcus Faecium ◽  
Copper Sulphate ◽  
Copper Resistance ◽  
Putative Promoter ◽  
Promoter Probe ◽  
Copper Resistance Gene ◽  
Promoter Probe Vector ◽  
Isogenic Strains ◽  
Sublethal Concentrations

The plasmid-localized tcrB (transferable copper-resistance gene B) gene from Enterococcus faecium was identified to be part of an operon called the tcrYAZB operon, which has a genetic organization similar to the copYZAB copper-homeostasis gene cluster from Enterococcus hirae. Putative promoter (P tcr )- and repressor-binding sites highly similar to the E. hirae cop-promoter region were identified upstream of the tcrYAZB genes. The P tcr promoter was cloned in both the absence and the presence of the proximal repressor-encoding tcrY gene into a promoter-probe vector. Induction of the promoter was shown in liquid growth medium containing increasing concentrations of copper sulphate. To determine the growth advantage conferred by the tcrYAZB genes in a copper environment, a tcr-deletion mutant was isolated, and its growth was compared with that of its copper-resistant ancestor (strain A17sv1) in sublethal concentrations of copper sulphate. A competition assay using these two isogenic strains showed that copper sulphate concentrations of 3 mmol l−1 and above are sufficient to select for copper resistance.

scholarly journals tcrB, a Gene Conferring Transferable Copper Resistance in Enterococcus faecium: Occurrence, Transferability, and Linkage to Macrolide and Glycopeptide Resistance

2002 ◽  
Vol 46 (5) ◽  
pp. 1410-1416 ◽  
Author(s):  
Henrik Hasman ◽  
Frank M. Aarestrup
Keyword(s):  
Enterococcus Faecium ◽  
Antimicrobial Agents ◽  
Brain Heart Infusion ◽  
Copper Resistance ◽  
Conjugative Plasmid ◽  
Feed Additive ◽  
Strongly Correlated ◽  
Glycopeptide Resistance ◽  
Copper Resistance Gene ◽  
Infusion Agar

ABSTRACT A newly discovered gene, designated tcrB, which is located on a conjugative plasmid conferring acquired copper resistance in Enterococcus faecium, was identified in an isolate from a pig. The tcrB gene encodes a putative protein belonging to the CPx-type ATPase family with homology (46%) to the CopB protein from Enterococcus hirae. The tcrB gene was found in E. faecium isolated from pigs (75%), broilers (34%), calves (16%), and humans (10%) but not in isolates from sheep. Resistant isolates, containing the tcrB gene, grew on brain heart infusion agar plates containing up to 28 mM CuSO4 compared to only 4 mM for the susceptible isolates. Copper resistance, and therefore the presence of the tcrB gene, was strongly correlated to macrolide and glycopeptide resistance in isolates from pigs, and the tcrB gene was shown to be located on the same conjugative plasmid as the genes responsible for resistance to these two antimicrobial agents. The frequent occurrence of this new copper resistance gene in isolates from pigs, where copper sulfate is being used in large amounts as feed additive, suggests that the use of copper has selected for resistance.

Occurrence oftcrB, a Transferable Copper Resistance Gene, in Fecal Enterococci of Swine

2010 ◽  
Vol 7 (9) ◽  
pp. 1089-1097 ◽  
Author(s):  
Raghavendra G. Amachawadi ◽  
Nick W. Shelton ◽  
Megan E. Jacob ◽  
Xiaorong Shi ◽  
Sanjeev K. Narayanan ◽  
...  
Keyword(s):  
Resistance Gene ◽  
Copper Resistance ◽  
Copper Resistance Gene

scholarly journals Transcriptional analysis of the F0F1 ATPase operon of Corynebacterium glutamicum ATCC 13032 reveals strong induction by alkaline pH

Microbiology ◽  
2006 ◽  
Vol 152 (1) ◽  
pp. 11-21 ◽  
Author(s):  
Mónica Barriuso-Iglesias ◽  
Carlos Barreiro ◽  
Fabio Flechoso ◽  
Juan F. Martín
Keyword(s):  
Corynebacterium Glutamicum ◽  
Consensus Sequence ◽  
Transcriptional Analysis ◽  
Alkaline Ph ◽  
Promoter Regions ◽  
Stress Response Genes ◽  
Promoter Probe ◽  
Promoter Probe Vector ◽  
Reduced Rate ◽  
Extension Analysis

Corynebacterium glutamicum, a soil Gram-positive bacterium used for industrial amino acid production, was found to grow optimally at pH 7·0–9·0 when incubated in 5 litre fermenters under pH-controlled conditions. The highest biomass was accumulated at pH 9·0. Growth still occurred at pH 9·5 but at a reduced rate. The expression of the pH-regulated F0F1 ATPase operon (containing the eight genes atpBEFHAGDC) was induced at alkaline pH. A 7·5 kb transcript, corresponding to the eight-gene operon, was optimally expressed at pH 9·0. The same occurred with a 1·2 kb transcript corresponding to the atpB gene. RT-PCR studies confirmed the alkaline pH induction of the F0F1 operon and the existence of the atpI gene. The atpI gene, located upstream of the F0F1 operon, was expressed at a lower level than the polycistronic 7·5 kb mRNA, from a separate promoter (P-atp1). Expression of the major promoter of the F0F1 operon, designated P-atp2, and the P-atp1 promoter was quantified by coupling them to the pET2 promoter-probe vector. Both P-atp1 and P-atp2 were functional in C. glutamicum and Escherichia coli. Primer extension analysis identified one transcription start point inside each of the two promoter regions. The P-atp1 promoter fitted the consensus sequence of promoters recognized by the vegetative σ factor of C. glutamicum, whereas the −35 and −10 boxes of P-atp2 fitted the consensus sequence for σ H-recognized Mycobacterium tuberculosis promoters CC/GGGA/GAC 17–22 nt C/GGTTC/G, known to be involved in expression of heat-shock and other stress-response genes. These results suggest that the F0F1 operon is highly expressed at alkaline pH, probably using a σ H RNA polymerase.

Analysis of the promoter activities of the genes encoding three quinoprotein alcohol dehydrogenases in Pseudomonas putida HK5

Microbiology ◽  
2009 ◽  
Vol 155 (2) ◽  
pp. 594-603 ◽  
Author(s):  
Worrawat Promden ◽  
Alisa S. Vangnai ◽  
Hirohide Toyama ◽  
Kazunobu Matsushita ◽  
Piamsook Pongsawasdi
Keyword(s):  
Transcriptional Regulation ◽  
Pseudomonas Putida ◽  
Regulatory Network ◽  
Alcohol Oxidation ◽  
Gene Products ◽  
Response Regulators ◽  
Divergent Promoters ◽  
Promoter Probe ◽  
Genes Encoding ◽  
Promoter Probe Vector

The transcriptional regulation of three distinct alcohol oxidation systems, alcohol dehydrogenase (ADH)-I, ADH-IIB and ADH-IIG, in Pseudomonas putida HK5 was investigated under various induction conditions. The promoter activities of the genes involved in alcohol oxidation were determined using a transcriptional lacZ fusion promoter-probe vector. Ethanol was the best inducer for the divergent promoters of qedA and qedC, encoding ADH-I and a cytochrome c, respectively. Primary and secondary C3 and C4 alcohols and butyraldehyde specifically induced the divergent promoters of qbdBA and aldA, encoding ADH-IIB and an NAD-dependent aldehyde dehydrogenase, respectively. The qgdA promoter of ADH-IIG responded well to (S)-(+)-1,2-propanediol induction. In addition, the roles of genes encoding the response regulators exaE and agmR, located downstream of qedA, were inferred from the properties of exaE- or agmR-disrupted mutants and gene complementation tests. The gene products of both exaE and agmR were strictly necessary for qedA transcription. The mutation and complementation studies also suggested a role for AgmR, but not ExaE, in the transcriptional regulation of qbdBA (ADH-IIB) and qgdA (AGH-IIG). A hypothetical scheme describing a regulatory network, which directs expression of the three distinct alcohol oxidation systems in P. putida HK5, was derived.

scholarly journals The Rhizobium leguminosarum bv. viciae VF39 γ-aminobutyrate (GABA) aminotransferase gene (gabT) is induced by GABA and highly expressed in bacteroids The GenBank accession number for the sequence determined in this work is AF335502.

Microbiology ◽  
2002 ◽  
Vol 148 (2) ◽  
pp. 615-623 ◽  
Author(s):  
Jürgen Prell ◽  
Bert Boesten ◽  
Philip Poole ◽  
Ursula B Priefer
Keyword(s):  
Rhizobium Leguminosarum ◽  
Free Living ◽  
Carbon And Nitrogen ◽  
Gaba Aminotransferase ◽  
Gaba Metabolism ◽  
Promoter Probe ◽  
Promoter Probe Vector ◽  
Oxoglutarate Dehydrogenase ◽  
Substrate Specifities ◽  
Free Living Conditions

A Rhizobium leguminosarum bv. viciae VF39 gene (gabT) encoding a γ-aminobutyrate (GABA) aminotransferase was identified, cloned and characterized. This gene is thought to be involved in GABA metabolism via the GABA shunt pathway, a theoretical bypass of the 2-oxoglutarate dehydrogenase complex. Mutants in gabT are still able to grow on GABA as a sole carbon and nitrogen source. 2-Oxoglutarate-dependent GABA aminotransferase activity is absent in these mutants, while pyruvate-dependent activity remains unaffected. This indicates that at least two enzymes with different substrate specifities are involved in the GABA metabolism of R. leguminosarum bv. viciae VF39. The gabT promoter was cloned into a newly constructed, stable promoter-probe vector pJP2, suitable for the study of transcriptional GUS fusions in free-living bacteria and during symbiosis. Under free-living conditions the gabT promoter is induced by GABA and repressed by succinate. Transcriptional regulation is mediated by GabR in a repressor-like manner. During symbiosis with the pea host plant gabT is induced and highly expressed in the symbiotic zone. Nodules induced by gabT mutants, however, are still effective in nitrogen fixation.

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