Characterization of the aggregation promoting factor from Lactobacillus gasseri, avaginal isolate

Authors

  • S. Boris,

    1. Area de Microbiología, Departamento de Biología Funcional, InstitutoUniversitario de Biotecnología de Asturias, Facultad de Medicina, Universidad de Oviedo,Oviedo, Spain
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  • J.E. Suárez,

    1. Area de Microbiología, Departamento de Biología Funcional, InstitutoUniversitario de Biotecnología de Asturias, Facultad de Medicina, Universidad de Oviedo,Oviedo, Spain
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  • C. Barbés

    1. Area de Microbiología, Departamento de Biología Funcional, InstitutoUniversitario de Biotecnología de Asturias, Facultad de Medicina, Universidad de Oviedo,Oviedo, Spain
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Covadonga Barbés, Area de Microbiologia Departamento de Biología Funcional, Instituto Universitario de Biotecnología deAsturias, Facultad de Medicina, Universidad de Oviedo, 33006 Oviedo, Spain.

Abstract

Lactobacillus gasseri 2459, isolated from the human vagina, exhibits a strongautoaggregating phenotype. Filter-sterilized spent supernatants of this strain promote aggregationof Lact. plantarum LL441 and Enterococcus faecalis EF. Aggregation wasabolished upon exposure of the cells to proteases and, in the case of Ent. faecalis, tometaperiodate, which suggests the involvement of cell-surface proteins and glycoproteins,respectively, in the aggregation phenotype. In accordance with this, a 75 kDa surface protein, andpossibly another of approximately 94 kDa, appears in Lact. plantarum LL441 culturesincubated with Lact. gasseri culture supernatants. The diffusible aggregation promotingfactor was purified from stationary phase culture supernatants and determined to be a 2 kDahydrophilic peptide active at pH 3–4 and stable at neutral and acid pH. The activity wasresistant to heat, chymotrypsin, chelating agents, triton X-100 and reducing agents, but sensitiveto other proteases and SDS.

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