Open AccessA Mutation in Flavobacterium psychrophilum tlpB Inhibits Gliding Motility and Induces Biofilm Formation
Author(s) -
Beatriz Álvarez,
Pablo Secades,
Miguel A. Prieto,
Mark J. McBride,
José A. Guijarro
Publication year - 2006
Publication title -
applied and environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.552
H-Index - 324
eISSN - 1070-6291
pISSN - 0099-2240
DOI - 10.1128/aem.00128-06
Subject(s) - complementation , periplasmic space , biology , operon , mutant , biofilm , flavobacterium , transmembrane protein , microbiology and biotechnology , biochemistry , oxidoreductase , cytophaga , motility , transmembrane domain , gene , bacteria , genetics , escherichia coli , pseudomonas , enzyme , receptor
Flavobacterium psychrophilum is a psychrotrophic, fish-pathogenic bacterium belonging to theCytophaga-Flavobacterium-Bacteroides group. Tn4351 -induced mutants deficient in gliding motility, growth on iron-depleted media, and extracellular proteolytic activity were isolated. Some of these mutants were affected in only one of these characteristics, whereas others had defects in two or more. FP523, a mutant deficient in all of these properties, was studied further. FP523 had a Tn4351 insertion intlpB (thiol oxidoreductase-like protein gene), which encodes a 41.4-kDa protein whose sequence does not exhibit high levels of similar to the sequences of proteins having known functions. TlpB has two domains; the N-terminal domains has five transmembrane regions, whereas the C-terminal domains has the Cys-X-X-Cys motif and other conserved motifs characteristic of thiol:disulfide oxidoreductases. Quantitative analysis of the thiol groups of periplasmic proteins revealed that TlpB is required for reduction of these groups. ThetlpB gene is part of thefpt (F. psychrophilum thiol oxidoreductase) operon that contains two other genes,tlpA andtpiA , which encode a thiol:disulfide oxidoreductase and a triosephosphate isomerase, respectively. FP523 exhibited enhanced biofilm formation and decreased virulence and cytotoxicity. Complementation with thetlpB loci restored the wild-type phenotype. Gliding motility and biofilm formation appear to be antagonistic properties, which are both affected by TlpB.