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CRP-Mediated Carbon Catabolite Regulation of Yersinia pestis Biofilm Formation Is Enhanced by the Carbon Storage Regulator Protein, CsrA.

Willias SP, Chauhan S, Lo CC, Chain PS, Motin VL - PLoS ONE (2015)

Bottom Line: Media supplementation with cAMP, a small-molecule activator of CRP, did not significantly alter Y. pestis biofilm production.Therefore, our findings indicate CRP does not confer a direct stimulatory effect, but may indirectly promote Y. pestis biofilm production by facilitating the alternate carbon source expression profile.Loss of csrA did not significantly alter relative hmsH, hmsP, or hmsT mRNA abundance.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America.

ABSTRACT
The natural transmission of Yersinia pestis is reliant upon biofilm blockage of the flea vector. However, the environmentally-responsive adaptive regulators which facilitate Y. pestis biofilm production in accordance with the flea midgut milieu are not well understood. We seek to establish the impact of available carbon source metabolism and storage upon Y. pestis biofilm production. Our findings demonstrate that Y. pestis biofilm production is subject to carbon catabolite regulation in which the presence of glucose impairs biofilm production; whereas, the sole metabolism of alternate carbon sources promotes robust biofilm formation. This observation is facilitated by the cAMP receptor protein, CRP. In accordance with a stark growth defect, deletion of crp in both CO92 and KIM6+ Y. pestis strains significantly impaired biofilm production when solely utilizing alternate carbon sources. Media supplementation with cAMP, a small-molecule activator of CRP, did not significantly alter Y. pestis biofilm production. Furthermore, CRP did not alter mRNA abundance of previously-characterized hms biofilm synthesis and regulation factors. Therefore, our findings indicate CRP does not confer a direct stimulatory effect, but may indirectly promote Y. pestis biofilm production by facilitating the alternate carbon source expression profile. Additionally, we assessed the impact of the carbon storage regulator protein, CsrA, upon Y. pestis biofilm production. Contrary to what has been described for E. coli, Y. pestis biofilm formation was found to be enhanced by CsrA. Regardless of media composition and available carbon source, deletion of csrA significantly impaired Y. pestis biofilm production. CsrA was found to promote Y. pestis biofilm production independent of glycogen regulation. Loss of csrA did not significantly alter relative hmsH, hmsP, or hmsT mRNA abundance. However, deletion of hmsP in the csrA-deficient mutant enabled excessive biofilm production, suggesting CsrA enables potent Y. pestis biofilm production through cyclic diguanylate regulation.

No MeSH data available.


Related in: MedlinePlus

Y. pestis Biofilm Production is not Influenced by Exogenous cAMP.(A) Relative biofilm production of KIM6+ and KIM6+Δcrp when grown in BCS medium supplemented with 0.2% glucose containing either 3 mM cAMP prepared in K-phosphate buffer or an equal volume of plain K-phosphate buffer. (B) Relative biofilm production of CO92 and CO92Δcrp when grown in BCS medium supplemented with 0.2% glucose containing either 3 mM cAMP prepared in K-phosphate buffer or an equal volume of plain K-phosphate buffer. Identical source inoculum per strain was utilized for each media type. Error bars reflect standard deviation from the mean derived from two independent experiments, each consisting of 6 technical replicates. No statistically significant change in crystal violet absorption as determined by one-way ANOVA was calculated for both the crp-deficient mutants and the respective parental controls when cultured in media containing 3mM cAMP or an equal volume of K-phosphate buffer.
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pone.0135481.g005: Y. pestis Biofilm Production is not Influenced by Exogenous cAMP.(A) Relative biofilm production of KIM6+ and KIM6+Δcrp when grown in BCS medium supplemented with 0.2% glucose containing either 3 mM cAMP prepared in K-phosphate buffer or an equal volume of plain K-phosphate buffer. (B) Relative biofilm production of CO92 and CO92Δcrp when grown in BCS medium supplemented with 0.2% glucose containing either 3 mM cAMP prepared in K-phosphate buffer or an equal volume of plain K-phosphate buffer. Identical source inoculum per strain was utilized for each media type. Error bars reflect standard deviation from the mean derived from two independent experiments, each consisting of 6 technical replicates. No statistically significant change in crystal violet absorption as determined by one-way ANOVA was calculated for both the crp-deficient mutants and the respective parental controls when cultured in media containing 3mM cAMP or an equal volume of K-phosphate buffer.

Mentions: We sought to assess if cAMP-dependent CRP activation is the determinant factor defining carbon catabolite regulation of robust Y. pestis biofilm production. Supplementation of BCS media containing 0.2% glucose as the sole carbon source with 3 mM cAMP did not significantly alter biofilm formation of the crp-deficient mutants or the respective isogenic controls (Fig 5). Therefore, cAMP availability is not solely responsible for the potent biofilm production observed during the metabolism of alternate carbon sources. Rather, CRP-mediated metabolism of alternate carbon sources enables robust Y. pestis biofilm production.


CRP-Mediated Carbon Catabolite Regulation of Yersinia pestis Biofilm Formation Is Enhanced by the Carbon Storage Regulator Protein, CsrA.

Willias SP, Chauhan S, Lo CC, Chain PS, Motin VL - PLoS ONE (2015)

Y. pestis Biofilm Production is not Influenced by Exogenous cAMP.(A) Relative biofilm production of KIM6+ and KIM6+Δcrp when grown in BCS medium supplemented with 0.2% glucose containing either 3 mM cAMP prepared in K-phosphate buffer or an equal volume of plain K-phosphate buffer. (B) Relative biofilm production of CO92 and CO92Δcrp when grown in BCS medium supplemented with 0.2% glucose containing either 3 mM cAMP prepared in K-phosphate buffer or an equal volume of plain K-phosphate buffer. Identical source inoculum per strain was utilized for each media type. Error bars reflect standard deviation from the mean derived from two independent experiments, each consisting of 6 technical replicates. No statistically significant change in crystal violet absorption as determined by one-way ANOVA was calculated for both the crp-deficient mutants and the respective parental controls when cultured in media containing 3mM cAMP or an equal volume of K-phosphate buffer.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4549057&req=5

pone.0135481.g005: Y. pestis Biofilm Production is not Influenced by Exogenous cAMP.(A) Relative biofilm production of KIM6+ and KIM6+Δcrp when grown in BCS medium supplemented with 0.2% glucose containing either 3 mM cAMP prepared in K-phosphate buffer or an equal volume of plain K-phosphate buffer. (B) Relative biofilm production of CO92 and CO92Δcrp when grown in BCS medium supplemented with 0.2% glucose containing either 3 mM cAMP prepared in K-phosphate buffer or an equal volume of plain K-phosphate buffer. Identical source inoculum per strain was utilized for each media type. Error bars reflect standard deviation from the mean derived from two independent experiments, each consisting of 6 technical replicates. No statistically significant change in crystal violet absorption as determined by one-way ANOVA was calculated for both the crp-deficient mutants and the respective parental controls when cultured in media containing 3mM cAMP or an equal volume of K-phosphate buffer.
Mentions: We sought to assess if cAMP-dependent CRP activation is the determinant factor defining carbon catabolite regulation of robust Y. pestis biofilm production. Supplementation of BCS media containing 0.2% glucose as the sole carbon source with 3 mM cAMP did not significantly alter biofilm formation of the crp-deficient mutants or the respective isogenic controls (Fig 5). Therefore, cAMP availability is not solely responsible for the potent biofilm production observed during the metabolism of alternate carbon sources. Rather, CRP-mediated metabolism of alternate carbon sources enables robust Y. pestis biofilm production.

Bottom Line: Media supplementation with cAMP, a small-molecule activator of CRP, did not significantly alter Y. pestis biofilm production.Therefore, our findings indicate CRP does not confer a direct stimulatory effect, but may indirectly promote Y. pestis biofilm production by facilitating the alternate carbon source expression profile.Loss of csrA did not significantly alter relative hmsH, hmsP, or hmsT mRNA abundance.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America.

ABSTRACT
The natural transmission of Yersinia pestis is reliant upon biofilm blockage of the flea vector. However, the environmentally-responsive adaptive regulators which facilitate Y. pestis biofilm production in accordance with the flea midgut milieu are not well understood. We seek to establish the impact of available carbon source metabolism and storage upon Y. pestis biofilm production. Our findings demonstrate that Y. pestis biofilm production is subject to carbon catabolite regulation in which the presence of glucose impairs biofilm production; whereas, the sole metabolism of alternate carbon sources promotes robust biofilm formation. This observation is facilitated by the cAMP receptor protein, CRP. In accordance with a stark growth defect, deletion of crp in both CO92 and KIM6+ Y. pestis strains significantly impaired biofilm production when solely utilizing alternate carbon sources. Media supplementation with cAMP, a small-molecule activator of CRP, did not significantly alter Y. pestis biofilm production. Furthermore, CRP did not alter mRNA abundance of previously-characterized hms biofilm synthesis and regulation factors. Therefore, our findings indicate CRP does not confer a direct stimulatory effect, but may indirectly promote Y. pestis biofilm production by facilitating the alternate carbon source expression profile. Additionally, we assessed the impact of the carbon storage regulator protein, CsrA, upon Y. pestis biofilm production. Contrary to what has been described for E. coli, Y. pestis biofilm formation was found to be enhanced by CsrA. Regardless of media composition and available carbon source, deletion of csrA significantly impaired Y. pestis biofilm production. CsrA was found to promote Y. pestis biofilm production independent of glycogen regulation. Loss of csrA did not significantly alter relative hmsH, hmsP, or hmsT mRNA abundance. However, deletion of hmsP in the csrA-deficient mutant enabled excessive biofilm production, suggesting CsrA enables potent Y. pestis biofilm production through cyclic diguanylate regulation.

No MeSH data available.


Related in: MedlinePlus