CONICET | Buscador de Institutos y Recursos Humanos

Bordetella bronchiseptica like other pathogens forms biofilm-like structures. Previously we have made progress inanalyzing the effect of changes in the intracellular concentration of the second messenger c-di-GMP on biofilmformation of B. bronchiseptica.In Pseudomonas fluorescens a group of three proteins designed large adhesin proteins (Lap) proteins are involvedcontrols biofilm formation by inside-out signaling and surface protein cleavage. LapA binding to the cell surface iscontrolled by LapD, which can bind c-di-GMP promoting biofilm formation through LapA accumulation on the cellsurface. LapG is a periplasmic calcium-dependent cysteine protease that cleaves cell surface LapA, preventing biofilmformation. Accordingly, when LapG is overexpressed biofilm is prevented.In the present work, homology to LapD, LapG and LapA was observed with B. bronchiseptica proteins BB1184,BB1185 and BB1186 respectively. To evaluate functionality, BB1185 (LapG ) gene from B. bronchiseptica was Bbcloned and transformed in P. fluorescens with deleted lapG. Biofilm development in the recombinant bacteria wasimpaired when LapG was expressed, corroborating functionality of this protein. Bb When lapG was overexpressed in B. bronchiseptica produced significantly less biofilm than parental strain on Bbabiotic surface when was determined by the cristal violet method. Surprisingly when Stainer-Scholte medium wassupplemented with calcium biofilm formation was significantly enhanced in all strains tested. In these conditionsBb-LapG biofilm levels were also below those observed for wild type strain corroborating that LapG is involved Bb Bbin biofilm development. Further studies are in process to determinate if Lap system is important to biofilmdevelopment in vivo.