A Novel Norspermidine Responsive Signaling Pathway in Vibrio Cholerae Affecting Biofilm Formation

ASU Author/Contributor (non-ASU co-authors, if there are any, appear on document)
Steven Randolph Cockerell (Creator)
Appalachian State University (ASU )
Web Site: https://library.appstate.edu/
Ece Karatan

Abstract: Polyamines are a class of simple molecules that are nearly ubiquitous to life. As signals they are involved in cell signaling and cellular processes. In the aquatic pathogen Vibrio cholerae it has been shown that the polyamine norspermidine dramatically affects biofilm formation. Addition of norspermidine to cultures of V. cholerae will cause up to a threefold increase in biofilm formation compared to untreated cells. Two proteins are implicated in the cells response to norspermidine. The periplasmic protein NspS and the integral inner-membrane protein MbaA. The protein NspS is similar to periplasmic transport proteins involved in the transport of polyamines and MbaA is similar to proteins involved in degrading the second messenger c-di-GMP. The second messenger c-di-GMP at low intracellular concentrations leads to less biofilm formation and higher levels lead to increased biofilm formation. It was hypothesized that NspS senses norspermidine and in turn affects the activity of MbaA which could affect biofilm formation. NspS was first analyzed for the ability to bind norspermidine via a thermal shift assay. When a pure sample of NspS was exposed to norspermidine there was a dramatic shift in thermal stability over NspS without norspermidine. The increase in thermal stability indicates binding. Further, MbaA was shown directly to be capable of degrading molecules of c-di-GMP confirming it acts as a phosphodiesterase. The data generated in this study provides evidence for a new signaling system in which norspermidine regulates biofilm formation.

Additional Information

Cockerell, S.R. (2013). A Novel Norspermidine Responsive Signaling Pathway in Vibrio Cholerae Affecting Biofilm Formation. Unpublished master’s thesis. Appalachian State University, Boone, NC.
Language: English
Date: 2013
Vibrio cholerae, c-di-GMP, Phosphodiesterase, Polyamine, Biofilm

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