Limits...
A Serratia marcescens PigP homolog controls prodigiosin biosynthesis, swarming motility and hemolysis and is regulated by cAMP-CRP and HexS.

Shanks RM, Lahr RM, Stella NA, Arena KE, Brothers KM, Kwak DH, Liu X, Kalivoda EJ - PLoS ONE (2013)

Bottom Line: Transcriptional analysis and electrophoretic mobility shift assays place PigP in a regulatory pathway with upstream regulators CRP and HexS.The data from this study identifies a positive regulator of serratamolide production, describes novel roles for the PigP transcription factor, shows for the first time that PigP directly regulates the pigment biosynthetic operon, and identifies upstream regulators of pigP.This study suggests that PigP is important for the ability of S. marcescens to compete in the environment.

View Article: PubMed Central - PubMed

Affiliation: Charles T Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh Eye Center, Pittsburgh, Pennsylvania, United States of America.

ABSTRACT
Swarming motility and hemolysis are virulence-associated determinants for a wide array of pathogenic bacteria. The broad host-range opportunistic pathogen Serratia marcescens produces serratamolide, a small cyclic amino-lipid, that promotes swarming motility and hemolysis. Serratamolide is negatively regulated by the transcription factors HexS and CRP. Positive regulators of serratamolide production are unknown. Similar to serratamolide, the antibiotic pigment, prodigiosin, is regulated by temperature, growth phase, HexS, and CRP. Because of this co-regulation, we tested the hypothesis that a homolog of the PigP transcription factor of the atypical Serratia species ATCC 39006, which positively regulates prodigiosin biosynthesis, is also a positive regulator of serratamolide production in S. marcescens. Mutation of pigP in clinical, environmental, and laboratory strains of S. marcescens conferred pleiotropic phenotypes including the loss of swarming motility, hemolysis, and severely reduced prodigiosin and serratamolide synthesis. Transcriptional analysis and electrophoretic mobility shift assays place PigP in a regulatory pathway with upstream regulators CRP and HexS. The data from this study identifies a positive regulator of serratamolide production, describes novel roles for the PigP transcription factor, shows for the first time that PigP directly regulates the pigment biosynthetic operon, and identifies upstream regulators of pigP. This study suggests that PigP is important for the ability of S. marcescens to compete in the environment.

Show MeSH

Related in: MedlinePlus

PigP is necessary for hemolysis in laboratory and clinical isolates. A. Hemolytic strains grown on TSA plates with sheep blood show a zone of clearing around colonies indicative of hemolysis. Isogenic pigP mutant strains show highly reduced zones of hemolysis. B. The hemolysis defect of pigP mutants can be complemented by wild-type pigP on a plasmid (pMQ221); vector refers to pMQ132. C. Arabinose inducible expression of swrW is sufficient to restore hemolysis to the pigP mutant. The swrW gene was expressed from plasmid pMQ367 (pswrW), and vector refers to pMQ125. D. Mutation of pigP reduces the hyper-hemolytic phenotypes of crp and hexS mutants.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3585978&req=5

pone-0057634-g006: PigP is necessary for hemolysis in laboratory and clinical isolates. A. Hemolytic strains grown on TSA plates with sheep blood show a zone of clearing around colonies indicative of hemolysis. Isogenic pigP mutant strains show highly reduced zones of hemolysis. B. The hemolysis defect of pigP mutants can be complemented by wild-type pigP on a plasmid (pMQ221); vector refers to pMQ132. C. Arabinose inducible expression of swrW is sufficient to restore hemolysis to the pigP mutant. The swrW gene was expressed from plasmid pMQ367 (pswrW), and vector refers to pMQ125. D. Mutation of pigP reduces the hyper-hemolytic phenotypes of crp and hexS mutants.

Mentions: A recent report indicates that serratamolide can be hemolytic [22]. We tested the prediction that pigP mutants would be defective in hemolysis. The ΔpigP strain (CMS1713) made no zone of clearing on blood agar plates, whereas the WT strain did, and this defect could be complemented by WT pigP on a plasmid (Figure 6A–B). A reduction or elimination of secreted hemolytic activity was also observed when pigP was disrupted in the WT and Nima laboratory strains, and clinical isolates K904 and K997 (Figure 6A). Arabinose-inducible expression of swrW from the ΔpigP mutant was able to restore hemolysis to the pigP mutant (Figure 6C), supporting that a reduction of swrW expression was responsible for the hemolysis defect of pigP mutants.


A Serratia marcescens PigP homolog controls prodigiosin biosynthesis, swarming motility and hemolysis and is regulated by cAMP-CRP and HexS.

Shanks RM, Lahr RM, Stella NA, Arena KE, Brothers KM, Kwak DH, Liu X, Kalivoda EJ - PLoS ONE (2013)

PigP is necessary for hemolysis in laboratory and clinical isolates. A. Hemolytic strains grown on TSA plates with sheep blood show a zone of clearing around colonies indicative of hemolysis. Isogenic pigP mutant strains show highly reduced zones of hemolysis. B. The hemolysis defect of pigP mutants can be complemented by wild-type pigP on a plasmid (pMQ221); vector refers to pMQ132. C. Arabinose inducible expression of swrW is sufficient to restore hemolysis to the pigP mutant. The swrW gene was expressed from plasmid pMQ367 (pswrW), and vector refers to pMQ125. D. Mutation of pigP reduces the hyper-hemolytic phenotypes of crp and hexS mutants.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3585978&req=5

pone-0057634-g006: PigP is necessary for hemolysis in laboratory and clinical isolates. A. Hemolytic strains grown on TSA plates with sheep blood show a zone of clearing around colonies indicative of hemolysis. Isogenic pigP mutant strains show highly reduced zones of hemolysis. B. The hemolysis defect of pigP mutants can be complemented by wild-type pigP on a plasmid (pMQ221); vector refers to pMQ132. C. Arabinose inducible expression of swrW is sufficient to restore hemolysis to the pigP mutant. The swrW gene was expressed from plasmid pMQ367 (pswrW), and vector refers to pMQ125. D. Mutation of pigP reduces the hyper-hemolytic phenotypes of crp and hexS mutants.
Mentions: A recent report indicates that serratamolide can be hemolytic [22]. We tested the prediction that pigP mutants would be defective in hemolysis. The ΔpigP strain (CMS1713) made no zone of clearing on blood agar plates, whereas the WT strain did, and this defect could be complemented by WT pigP on a plasmid (Figure 6A–B). A reduction or elimination of secreted hemolytic activity was also observed when pigP was disrupted in the WT and Nima laboratory strains, and clinical isolates K904 and K997 (Figure 6A). Arabinose-inducible expression of swrW from the ΔpigP mutant was able to restore hemolysis to the pigP mutant (Figure 6C), supporting that a reduction of swrW expression was responsible for the hemolysis defect of pigP mutants.

Bottom Line: Transcriptional analysis and electrophoretic mobility shift assays place PigP in a regulatory pathway with upstream regulators CRP and HexS.The data from this study identifies a positive regulator of serratamolide production, describes novel roles for the PigP transcription factor, shows for the first time that PigP directly regulates the pigment biosynthetic operon, and identifies upstream regulators of pigP.This study suggests that PigP is important for the ability of S. marcescens to compete in the environment.

View Article: PubMed Central - PubMed

Affiliation: Charles T Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh Eye Center, Pittsburgh, Pennsylvania, United States of America.

ABSTRACT
Swarming motility and hemolysis are virulence-associated determinants for a wide array of pathogenic bacteria. The broad host-range opportunistic pathogen Serratia marcescens produces serratamolide, a small cyclic amino-lipid, that promotes swarming motility and hemolysis. Serratamolide is negatively regulated by the transcription factors HexS and CRP. Positive regulators of serratamolide production are unknown. Similar to serratamolide, the antibiotic pigment, prodigiosin, is regulated by temperature, growth phase, HexS, and CRP. Because of this co-regulation, we tested the hypothesis that a homolog of the PigP transcription factor of the atypical Serratia species ATCC 39006, which positively regulates prodigiosin biosynthesis, is also a positive regulator of serratamolide production in S. marcescens. Mutation of pigP in clinical, environmental, and laboratory strains of S. marcescens conferred pleiotropic phenotypes including the loss of swarming motility, hemolysis, and severely reduced prodigiosin and serratamolide synthesis. Transcriptional analysis and electrophoretic mobility shift assays place PigP in a regulatory pathway with upstream regulators CRP and HexS. The data from this study identifies a positive regulator of serratamolide production, describes novel roles for the PigP transcription factor, shows for the first time that PigP directly regulates the pigment biosynthetic operon, and identifies upstream regulators of pigP. This study suggests that PigP is important for the ability of S. marcescens to compete in the environment.

Show MeSH
Related in: MedlinePlus