Functionality of the S-layer protein from the probiotic strain Lactobacillus helveticus M92

Probiotička bakterija Lactobacillus helveticus M92 sintetizira površinski S-layer protein (SlpA) čija biološka uloga još uvijek nije u potpunosti objašnjena. Stoga je cilj ovoga rada ispitati funkcionalnu ulogu S-layer proteina bakterije L. helveticus M92 u probiotičkom djelovanju L. helveticus M92. Nakon što je prisutnost SlpA proteina utvrđena pomoću SDS-PAGE površinskih proteina i primjenom specifičnih početnica za slpA L. helveticus, istražena je uloga ovog proteina u adheziji L. helveticus M92 na Caco-2 epitelne stanice. Provedena je ekstrakcija SlpA proteina s površine stanica L. helveticus M92 pomoću 5M litijeva klorida, te je uspoređena adhezija bakterijskih stanica L. helveticus M92 na Caco-2 epitelne stanice, prije i nakon uklanjanja S-layer proteina s površine bakterijske stanice. Uklanjanje S-layer proteina s površine stanice L. helveticus M92 utjecao je na smanjenje adhezije ove probiotičke bakterije na Caco-2 epitelne stanice. Također je ispitana koagregacija ovog probiotičkog soja sa Salmonella Typhimurium FP1, istražena uloga S-layer proteina u koagregaciji i kompetitivnoj ekskluziji S. Typhimurium FP1 na Caco-2 epitelne stanice. Iz dobivenih rezultata uočljiva je inhibicija adhezije S. Typhimurium FP1 u prisustvu L. helveticus M92.The probiotic strain Lactobacillus helveticus M92 synthesizes surface S-layer protein (SlpA) whose biological function has not yet been complettly explained. Therefore, the aim of this paper is to investigate functionality of the S-layer protein from the probiotic strain L. helveticus M92 in the probiotic activity of this strain. The presence of SlpA protein was identified by SDS-PAGE of surface proteins and by PCR with a primers specific for slpA of L. helveticus. A role of this protein in adhesion of L. helveticus M92 at Caco-2 epithelial cells was also examined. SlpA protein was extracted from the cell surface of L. helveticus M92 by 5 M lithium chloride. The adhesion of L. helveticus M92 bacterial cells to Caco-2 cell line was compared before and after the removal of S-layer protein from the bacterial surface. The removal of S-layer protein from L. helveticus M92 bacterial surface reduced the adhesion of this probiotic strain to Caco-2 epithelial cells. Coaggregation of this probiotic strain with S. Typhiumurium FP1 was also performed and the role of S-layer protein in coaggregation and competitive exclusion of S. Typhimurium FP1 at Caco-2 epithelial cells was investigated. The inhibition of adhesion of S. Typhimurium FP1 in the presence of L. helveticus M92 was obvious from the results