title: Elevated levels of the norspermidine synthesis enzyme NspC enhance Vibrio cholerae biofilm formation without affecting intracellular norspermidine concentrations.
abstract: Biofilm formation in Vibrio cholerae is in part regulated by norspermidine, a polyamine synthesized by the enzyme carboxynorspermidine decarboxylase (NspC). The absence of norspermidine in the cell leads to a marked reduction in V. cholerae biofilm formation by an unknown mechanism. In this work, we show that overexpression of nspC results in large increases in biofilm formation and vps gene expression as well as a significant decrease in motility. Interestingly, increased NspC levels do not lead to increased concentrations of norspermidine in the cell. Our results show that NspC levels inversely regulate biofilm and motility and implicate the presence of an effective feedback mechanism maintaining norspermidine homeostasis in V. cholerae. Moreover, we provide evidence that NspC and the norspermidine sensor protein, NspS, provide independent and distinct inputs into the biofilm regulatory network.
authors.affiliation: Department of Biology, Appalachian State University, Boone, NC 27599, USA.
authors.forename: Zachary M
authors.initials: ZM
authors.lastname: Parker
authors.forename: Samuel S
authors.initials: SS
authors.lastname: Pendergraft
authors.forename: Jim
authors.initials: J
authors.lastname: Sobieraj
authors.forename: Marcus M
authors.initials: MM
authors.lastname: McGinnis
authors.forename: Ece
authors.initials: E
authors.lastname: Karatan
mesh_terms: D001426:Bacterial Proteins / Q000096:biosynthesis*; D018441:Biofilms / Q000254:growth & development*; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D008124:Locomotion; D013095:Spermidine / Q000031:analogs & derivatives* / Q000096:biosynthesis; D014734:Vibrio cholerae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*
chemical_list: D001426:Bacterial Proteins; C006760:norspermidine; D013095:Spermidine