IIBBA   05544
INSTITUTO DE INVESTIGACIONES BIOQUIMICAS DE BUENOS AIRES
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
BtaE and BtaF: two members of the trimeric autotransporter family involved in adhesion of Brucella suis to host cells
Autor/es:
RUIZ, V.; POSADAS, D.M.; ABDIAN, P.L.; MARTIN, F.A.; AROCENA, G.M.; SIEIRA, R.; ZORREGUIETA, A.
Lugar:
San Miguel de Tucumán
Reunión:
Congreso; VII Congreso Argentino de Microbiología General, SAMIGE del Bicentenario; 2011
Resumen:
Species belonging to the Brucella genera are intracellular pathogens responsible of an endemic
disease called brucellosis that causes important economic losses. Even though the intracellular
traffic of Brucella was well characterized, the adhesion of Brucella to the host cell was little
explored. By phage display we have previously identified a protein from the monomeric
autotransporter family (BmaC) that is involved in the attachment of Brucella suis to epithelial
cells, probably by interaction with fibronectin. By bioinformatical analysis of the B. suis genome
we identified two putative adhesins belonging to the trimeric autotransporter family: BtaE and
BtaF. By inmunofluorescence we confirmed that both proteins are exposed on the bacterial
surface, as expected for adhesins.
We generated clean deletion mutants in the btaE and btaF genes of B. suis 1330. Both mutants
showed a marked loss in its ability to attach to HeLa cells. Interestingly, the BtaE mutant had a
reduced ability to bind to immobilized hyaluronic acid, while the BtaF showed a reduced
attachment not only to hyaluronic acid but to other components of the extracellular matrix
(ECM), such as fibronectin and collagen.
By heterologous expression of btaE or btaF in a non adherent-non invasive E. coli strain we
showed that BtaE confers to E. coli the ability to interact with hialuronic acid while BtaF confers
the ability to interact with hyaluronic, collagen and fibronectin. These observations are
consistent with the adhesive phenotypes of BtaE and BtaF mutants. Finally, the strain of E.
coli expressing btaF showed an enhanced ability to attach to plastic (hydrophobic), but not to
glass (hydrophilic).
These results suggest that both BtaE and BtaF are involved in the adhesion to eukaryotic cells
by a process that could involve the interaction with components of the ECM.
Taken together, our observations indicate that adhesion of B. suis to host cells would be
mediated by multiple adhesins. Alternatively, different bacterial adhesins may contribute to a
differential tissue tropism.