The map locus of Brucella suis is involved in cell envelope biogenesis and virulence.

BIALER MG; RUIZ-RANWEZ V; ESTEIN SM; RUSSO DM; ALTABE SG; ZORREGUIETA A

Cordoba

Congreso; SAIB - 52 th Annual Meeting.; 2016

SAIB

THEmap LOCUSOFBrucella suisIS INVOLVED IN CELL ENVELOPE BIOGENESIS ANDVIRULENCEBialer MG1, Ruiz-Ranwez V1, Estein SM2, Russo DM1, Altabe SG3, Sycz G1, Zorreguieta A1.1Fundación Instituto Leloir, IIBBA-CONICET, Bs.As. 2CIVETAN-CONICET, Tandil. 3IBR-CONICET, Rosario.E-mail: mbialer@leloir.org.arBrucellaspecies exhibit unique surface properties, which make them furtive pathogens and more resistant to several host defensecompounds. We have identified alocusofBrucella suis encoding the MapA and MapB proteins, which are predicted to represent theTAM machinery, recently proposed to participate in the translocation/insertion of autotransporters (ATs) in the outer membrane (OM).InBrucella, ATs are involved in bacterial attachment to host components. However, the role of TAM inB. suiswould not be restrictedto AT translocation since the∆mapB phenotypes were not only related to adhesion functions. Indeed, ∆mapBshowed enhancedsensitivity to lysozyme, Triton X-100 and polymyxin B, indicating that the cell envelope integrity is compromised. This effect was notdue to major differences in the LPS structure or to altered total fatty acid composition. Analysis by LC-MS/MS and WesternBlot ofmembrane fractions suggested that the extent of some OM proteins is slightly altered in themapBmutant. Interestingly, the number ofbacteria recovered from macrophages during the initial stages of infection was reduced in the mutant and it showed an attenuatedphenotype in mice. These results suggest that MapA/MapB assists in the correct insertion of an unknown subset of protein substratesor other OM components, which are important for OM stability and virulence.