Differential Regulation of Twitching Motility and Elastase Production by Vfr in
            <i>Pseudomonas aeruginosa</i>

Beatson, Scott A.; Whitchurch, Cynthia B.; Sargent, Jennifer L.; Levesque, Roger C.; Mattick, John S.

doi:10.1128/jb.184.13.3605-3613.2002

Cited by 173 publications

(149 citation statements)

References 57 publications

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“…However, complete understanding of the CRP regulon is lacking. Notably, CRP and its homologs in other microorganisms were found to control factors that could affect biofilm formation: twitching motility, elastase production, and quorum sensing in Pseudomonas (1,5), type IV pili in Vibrio cholerae (37), and flagella and/or motility in E. coli and Salmonella enterica serovar Typhimurium (45). The third regulator targeted in our study was the homolog of the E. coli ArcA response regulator (79% identity and 86% similarity).…”

Section: Discussionmentioning

confidence: 99%

Induction of Rapid Detachment in Shewanella oneidensis MR-1 Biofilms

Thormann¹,

Saville²,

Shukla³

et al. 2005

J Bacteriol

197

198

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Active detachment of cells from microbial biofilms is a critical yet poorly understood step in biofilm development. We discovered that detachment of cells from biofilms of Shewanella oneidensis MR-1 can be induced by arresting the medium flow in a hydrodynamic biofilm system. Induction of detachment was rapid, and substantial biofilm dispersal started as soon as 5 min after the stop of flow. We developed a confocal laser scanning microscopy-based assay to quantify detachment. The extent of biomass loss was found to be dependent on the time interval of flow stop and on the thickness of the biofilm. Up to 80% of the biomass of 16-h-old biofilms could be induced to detach. High-resolution microscopy studies revealed that detachment was associated with an overall loosening of the biofilm structure and a release of individual cells or small cell clusters. Swimming motility was not required for detachment. Although the loosening of cells from the biofilm structure was observed evenly throughout thin biofilms, the most pronounced detachment in thicker biofilms occurred in regions exposed to the flow of medium, suggesting a metabolic control of detachability. Deconvolution of the factors associated with the stop of medium flow revealed that a sudden decrease in oxygen tension is the predominant trigger for initiating detachment of individual cells. In contrast, carbon limitation did not trigger any substantial detachment, suggesting a physiological link between oxygen sensing or metabolism and detachment. In-frame deletions were introduced into genes encoding the known and putative global transcriptional regulators ArcA, CRP, and EtrA (FNR), which respond to changes in oxygen tension in S. oneidensis MR-1. Biofilms of null mutants in arcA and crp were severely impacted in the stop-of-flow-induced detachment response, suggesting a role for these genes in regulation of detachment. In contrast, an ⌬etrA mutant displayed a variable detachment phenotype. From this genetic evidence we conclude that detachment is a biologically controlled process and that a rapid change in oxygen concentration is a critical factor in detachment and, consequently, in dispersal of S. oneidensis cells from biofilms. Similar mechanisms might also operate in other bacteria.

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Section: Discussionmentioning

confidence: 99%

Induction of Rapid Detachment in Shewanella oneidensis MR-1 Biofilms

Thormann¹,

Saville²,

Shukla³

et al. 2005

J Bacteriol

197

198

View full text Add to dashboard Cite

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“…Vrf, a homologue of Escherichia coli cyclic AMP receptor protein, positively regulates elastase and pyocyanin production via activation of the transcriptional regulator LasR (2). Posttranscriptional control by DskA is required for full translation of the lasB elastase gene and the rhamnosyltransferase-encoding rhlAB (17).…”

Section: Discussionmentioning

confidence: 99%

“…In Pseudomonas aeruginosa, several global regulators have been shown to contribute to the regulation of secondary metabolites and virulence determinants at the posttranscriptional level including Vfr (2,3,49), DksA (17), and RsmA (33). Vrf, a homologue of Escherichia coli cyclic AMP receptor protein, positively regulates elastase and pyocyanin production via activation of the transcriptional regulator LasR (2).…”

Section: Discussionmentioning

confidence: 99%

Distribution and Expression of the ZmpA Metalloprotease in the Burkholderia cepacia Complex

et al. 2005

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The distribution of the metalloprotease gene zmpA was determined among strains of the Burkholderia cepacia complex (Bcc). The zmpA gene was present in B. cepacia, B. cenocepacia, B. stabilis, B. ambifaria and B. pyrrocinia but absent from B. multivorans, B. vietnamiensis, B. dolosa, and B. anthina. The presence of zmpA generally correlated with extracellular proteolytic activity with the exception of five strains, which had zmpA but had no detectable proteolytic activity when skim milk agar was used as a substrate (zmpA protease deficient). Western immunoblot experiments with anti-ZmpA antibodies suggest that the zmpA protease-deficient strains do not secrete or accumulate detectable ZmpA. Transcriptional zmpA::lacZ fusions were introduced in selected strains of the Bcc. zmpA::lacZ was expressed in all strains, but expression was generally lower in the zmpA proteasedeficient strains than in the zmpA protease-proficient strains. Quantitative reverse transcriptase real-time PCR demonstrated that zmpA protease-deficient strains did express zmpA mRNA, although at various levels. ZmpA has previously been shown to be positively regulated by the CepIR quorum-sensing system. Addition of exogenous AHLs did not restore extracellular protease production to any of the zmpA protease-deficient strains; however, introduction of cepR in trans complemented protease activity in two of five strains. Extracellular proteolytic activity was restored by the presence of zmpA in trans in two of the five strains. These studies suggest that although some strains of the Bcc contain the zmpA gene, multiple factors may influence its expression.

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“…This migration results in the formation of caps and, hence, the mushroom-shaped microcolonies (178). Perhaps through chemotaxis (186), motile cells might climb on top of the stalk cells to access more nutrients (182,187). In citrate minimal medium the absence of mushroom-shaped microcolonies can be explained by the lack of nonmotile cells, and therefore no stalks can form (179).…”

Section: P Aeruginosa Microcolony Division Of Labormentioning

confidence: 99%

Division of Labor in Biofilms: the Ecology of Cell Differentiation

2015

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The dense aggregation of cells on a surface, as seen in biofilms, inevitably results in both environmental and cellular heterogeneity. For example, nutrient gradients can trigger cells to differentiate into various phenotypic states. Not only do cells adapt physiologically to the local environmental conditions, but they also differentiate into cell types that interact with each other. This allows for task differentiation and, hence, the division of labor. In this article, we focus on cell differentiation and the division of labor in three bacterial species: Myxococcus xanthus, Bacillus subtilis , and Pseudomonas aeruginosa . During biofilm formation each of these species differentiates into distinct cell types, in some cases leading to cooperative interactions. The division of labor and the cooperative interactions between cell types are assumed to yield an emergent ecological benefit. Yet in most cases the ecological benefits have yet to be elucidated. A notable exception is M. xanthus , in which cell differentiation within fruiting bodies facilitates the dispersal of spores. We argue that the ecological benefits of the division of labor might best be understood when we consider the dynamic nature of both biofilm formation and degradation.

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Differential Regulation of Twitching Motility and Elastase Production by Vfr in Pseudomonas aeruginosa

Cited by 173 publications

References 57 publications

Induction of Rapid Detachment in Shewanella oneidensis MR-1 Biofilms

Induction of Rapid Detachment in Shewanella oneidensis MR-1 Biofilms

Distribution and Expression of the ZmpA Metalloprotease in the Burkholderia cepacia Complex

Division of Labor in Biofilms: the Ecology of Cell Differentiation

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