Bordetella species display phase modulation between Bvg(+) and Bvg(-) phases. Because expression of known virulence factors is up-regulated in the Bvg(+) phase, bacteria in this phase are considered competent for infection. However, the Bvg(-) phase is of negligible importance for infection. No studies have shown that bacterial factors specific to the Bvg(-) phase (bvg-repressed factors) are expressed in the course of Bordetella infection. In the present study, the gene brtA (Bordetella RTX-family Adhesin), which is a typical bvg-repressed gene but is expressed in B. bronchiseptica infecting hosts, was characterized. BrtA is composed of repeated pairs of the VCBS unit and dystroglycan-type cadherin-like unit, the von Willebrand Factor A domain, RTX motif and type I secretion target signal. It is herein demonstrated that BrtA is secreted by the type I secretion system and is essential for Ca(2+) -dependent bacteria-to-substrate adherence, followed by biofilm formation. Although the contribution of BrtA to bacterial colonization of the rat trachea currently remains unclear, this is the first study to present concrete evidence for the expression of a bvg-repressed gene during infection, which may provide a novel aspect for analyses of Bordetella pathogenesis.
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http://dx.doi.org/10.1111/1348-0421.12356 | DOI Listing |
J Bacteriol
October 2018
Division of Bacterial, Parasitic, and Allergenic Products, Center for Biologics Evaluation and Research, FDA, Silver Spring, Maryland, USA.
In , two serologically distinct fimbriae, FIM2 and FIM3, undergo on/off phase variation independently of each other via variation in the lengths of C stretches in the promoters for their major subunit genes, and These two promoters are also part of the BvgAS virulence regulon and therefore, if in an on configuration, are activated by phosporylated BvgA (BvgA~P) under normal growth conditions (Bvg mode) but not in the Bvg mode, inducible by growth in medium containing MgSO or other compounds, termed modulators. In the Tohama I strain (FIM2 FIM3), the promoter is in the off state. However, a high level of transcription of the gene is observed in the Bvg mode.
View Article and Find Full Text PDFJ Infect Dis
May 2018
Section Pediatric Infectious Diseases, Laboratory of Medical Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, The Netherlands.
J Bacteriol
November 2017
Division of Bacterial, Parasitic, and Allergenic Products, Center for Biologics Evaluation and Research, FDA, Silver Spring, Maryland, USA.
The two-component response regulator RisA, encoded by open reading frame BP3554 in the Tohama I genomic sequence, is a known activator of genes, a set of genes whose expression is increased under the same environmental conditions (known as modulation) that result in repression of the virulence regulon. Here we demonstrate that RisA is phosphorylated and that RisA phosphorylation is required for activation of genes. An adjacent histidine kinase gene, , is truncated by frameshift mutation in but not in or Neither deletion of ' or nor phenotypic modulation with MgSO affected levels of phosphorylated RisA (RisA∼P) in However, RisA phosphorylation did require the histidine kinase encoded by BP3223, here named RisK (cognate histidine kinase of RisA).
View Article and Find Full Text PDFMicrobiol Immunol
February 2016
Department of Molecular Bacteriology, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamada-oka, Suita, Osaka 565-0871, Japan.
Bordetella species display phase modulation between Bvg(+) and Bvg(-) phases. Because expression of known virulence factors is up-regulated in the Bvg(+) phase, bacteria in this phase are considered competent for infection. However, the Bvg(-) phase is of negligible importance for infection.
View Article and Find Full Text PDFPLoS One
May 2013
National Animal Disease Center, Agricultural Research Service, USDA, Ames, Iowa, United States of America.
We have used microarray analysis to study the transcriptome of the bacterial pathogen Bordetella bronchiseptica over the course of five time points representing distinct stages of biofilm development. The results suggest that B. bronchiseptica undergoes a coordinately regulated gene expression program similar to a bacterial developmental process.
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