Roles of a TOLC homologue in Brucella suis

DIANA POSADAS; FERNANDO MARTIN; M. VICTORIA DELPINO; PABLO BALDI; ELEONORA CAMPOS; ANGELES ZORREGUIETA

Mexico

Congreso; 58 th Brucellosis. International Research Conference; 2005

Abstract The ability of Brucella to invade and survive within cells is the cornerstone of its virulence, yet the mecanisms underlying both processes are not clear. Membrane transport systems able to export macromolecules and toxic substances are crucial for bacterial survival and/or pathogenesis. Members of the TolC (or OMF Outer Membrane Factor) family are outer membrane proteins involved in the export of chemically diverse molecules ranging from large protein toxins to small toxic compounds. OMF components work in association with two inner-membrane-associated proteins, conforming a tripartite pump. We analized the possible function and relevance of the unique OMF of B. suis (Omf bs). TolC from E. coli has the peculiarity to participate in diverse transport functions. We performed functional complementation studies in a tolC mutant of E. coli carrying the omfBs gene of B. suis under the control of an inducible promoter. While some of the TolC functions, such as colicin E1 uptake and efflux of acriflavine and chloranphenicol were fully complemented by omfBs gene of B. suis, protein secretion was only partially restored. An insertional mutant in omfBS was found to be hypersensitive to several drugs. our results demostrate that the OmfBs protein participates in drug efflux. In addition, OmfBs may be potentially involved in other transport functions in B. suis.