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dc.contributor.authorArrizubieta, M. J.
dc.contributor.authorToledo-Arana, Alejandro
dc.contributor.authorAmorena, B.
dc.contributor.authorPenadés, José R.
dc.contributor.authorLasa, Inigo
dc.identifier.citationArrizubieta, M.J., Toledo-Arana, A., Amorena, B., Penades, J.R., Lasa, I. (2004). Calcium inhibits bap-dependent multicellular behavior in Staphylococcus aureus. Journal of Bacteriology, 186(22), 7490-7498.
dc.description.abstractBap (biofilm-associated protein) is a 254-kDa staphylococcal surface protein implicated in formation of biofilms by staphylococci isolated from chronic mastitis infections. The presence of potential EF-hand motifs in the amino acid sequence of Bap prompted us to investigate the effect of calcium on the multicellular behavior of Bap-expressing staphylococci. We found that addition of millimolar amounts of calcium to the growth media inhibited intercellular adhesion of and biofilm formation by Bap-positive strain V329. Addition of manganese, but not addition of magnesium, also inhibited biofilm formation, whereas bacterial aggregation in liquid media was greatly enhanced by metal-chelating agents. In contrast, calcium or chelating agents had virtually no effect on the aggregation of Bap-deficient strain M556. The biofilm elicited by insertion of bap into the chromosome of a biofilm-negative strain exhibited a similar dependence on the calcium concentration, indicating that the observed calcium inhibition was an inherent property of the Bap-mediated biofilms. Site-directed mutagenesis of two of the putative EF-hand domains resulted in a mutant strain that was capable of forming a biofilm but whose biofilm was not inhibited by calcium. Our results indicate that Bap binds Ca2+ with low affinity and that Ca2+ binding renders the protein noncompetent for biofilm formation and for intercellular adhesion. The fact that calcium inhibition of Bap-mediated multicellular behavior takes place in vitro at concentrations similar to those found in milk serum supports the possibility that this inhibition is relevant to the pathogenesis and/or epidemiology of the bacteria in the mastitis process.
dc.titleCalcium inhibits bap-dependent multicellular behavior in Staphylococcus aureus
dc.authorAddressInstituto Valenciano de Investigaciones Agrarias (IVIA), Carretera CV-315, Km. 10’7, 46113 Moncada (Valencia), Españaes 2004
dc.entidadIVIACentro de Tecnología Animal
dc.journal.titleJournal of Bacteriology

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