RESUMEN
Aim: Confirmation of the enzymatic activity of Class A sortase (SrtA) in probiotic strain Lactobacillus acidophilus associated with the adhesion properties. Materials & methods: SrtA from L. acidophilus ATCC 4356 was purified and its enzymatic properties was investigated by site-directed mutagenesis approach and the sensitivity to metal ions was also detected. Results: SrtA of L. acidophilus ATCC4356 can recognize LPxTG and LPxTD sorting motifs. The active sites of SrtA include His137, Cys198 and Arg205. Furthermore, acacetin can increase the activity of SrtA, while phenyl vinyl sulfone could effectively inhibit the activity of SrtA with an IC50 of 143.32 µg/ml. The adhesion ability of L. acidophilus was also decreased resulting from the inhibition of SrtA activity. Conclusion: The unique properties of SrtA of L. acidophilus can provide some insights into the development of high-adhesion Lactobacillus strains in the GI tract.
Asunto(s)
Aminoaciltransferasas/metabolismo , Adhesión Bacteriana , Proteínas Bacterianas/metabolismo , Cisteína Endopeptidasas/metabolismo , Intestinos/microbiología , Lactobacillus acidophilus/enzimología , Secuencia de Aminoácidos , Aminoaciltransferasas/química , Aminoaciltransferasas/genética , Proteínas Bacterianas/química , Proteínas Bacterianas/genética , Dominio Catalítico , Cisteína Endopeptidasas/química , Cisteína Endopeptidasas/genética , Estabilidad de Enzimas , Humanos , Lactobacillus acidophilus/genética , Lactobacillus acidophilus/fisiología , Alineación de SecuenciaRESUMEN
Lactic acid bacteria are the majority fermentation starter in the traditional fermented foods. In this research, a promising Lactobacillus plantarum was isolated from Sichuan pickle and its adhesion properties were analyzed in simulated gastrointestinal fluid with different methods. Meanwhile, the immunomodulatory effect of this strain was also evaluated in the Caco-2 cells. Results found that adhesion-related mub genes and other genes like lsp and tuf were upregulated in different culture times. Furthermore, L. plantarum cultured at alkaline environment revealed some anti-inflammation activity through inhibited expression of cytokine IL-8 and increased expression of anti-inflammatory cytokine IL-10 in Caco-2 cells. The texture of yogurt after fermented by this kind of isolated strain was also investigated, which provides the foundation for the further development and application of this kind of strain in food production. More investigations need to be carried out to determine whether this probiotic contributes to regulation of intestinal flora and prevention of gut inflammation.