title: CRP-Mediated Carbon Catabolite Regulation of Yersinia pestis Biofilm Formation Is Enhanced by the Carbon Storage Regulator Protein, CsrA.
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.
authors: Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America.
authors: Stephan P
authors: SP
authors: Willias
authors: Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America.
authors: Sadhana
authors: S
authors: Chauhan
authors: Bioscience Division, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America.
authors: Chien-Chi
authors: CC
authors: Lo
authors: Bioscience Division, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America.
authors: Patrick S G
authors: PS
authors: Chain
authors: Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America; Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America.
authors: Vladimir L
authors: VL
authors: Motin
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D018441:Biofilms / Q000254:growth & development*; D002244:Carbon / Q000378:metabolism*; D002373:Cyclic AMP Receptor Protein / Q000378:metabolism*; D017353:Gene Deletion; D006003:Glycogen / Q000378:metabolism; D007700:Kinetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D015010:Yersinia pestis / Q000235:genetics / Q000254:growth & development / Q000502:physiology*
chemical_list: D001426:Bacterial Proteins; D002373:Cyclic AMP Receptor Protein; D012333:RNA, Messenger; D002244:Carbon; D006003:Glycogen