The partial characterization of the antibacterial peptide bacteriocin G(2) produced by the probiotic bacteria Lactobacillus plantarum G(2)

Abstract

The aim of this study was the partial characterization of the antimicrobial peptide bacteriocin G, produced by probiotic bacteria Lactobacillus plantarum G(2), which was isolated from a clinical sample of a healthy person. Antimicrobial substance was secreted in the supernatant of an L. plantarum G(2) culture, and showed a diverse spectrum of antimicrobial activity of all the tested strains of the genera Lactobacillus and the pathogenic bacteria Staphylococcus aureus and Salmonella abony. Isoclectric focusing revealed that bacteriocin G(2) is a cationic peptide (pI about 10) with a molecular mass of 2.2 kDa according to tricine sodium dodecyl sulphate polyacrylamide gel electrophoresis, SDS-PAGE. The antimicrobial activity of bactcriocin G(2) was diminished by the proteolytic action of trypsin and proteinase K. Bacteriocin G(2) preserved its biological activity in the temperature range 40-60 degrees C (15 min), which was lost at 80 degrees C. Bacteriocin G(2) was stable in the pH range 2-9, while treatment with 1 % Tween 80 and 1 % urea resulted in increased antimicrobial activity. The probiotic strain L. plantarum G(2) produces the antimicrobial substance proteinaceous in nature with bacteriocin characteristics. Bacteriocin production is one of the key properties of probiotic bacteria with clinical potential as anti-infective agents, which will increase the likelihood of its in vivo efficacy.

Cilj ovog istraživanja je bila parcijalna karakterizacija antimikrobnog peptida iz probiotske bakterija Lactobacillus plantarum G2 izolovane iz kliničkog uzorka zdrave osobe. Antimikrobno jedinjenje iz L. plantarum G2, označeno kao bakteriocin G2, dobijeno iz supernatanta bakterijske kulture, pokazalo je širok spektar antimikrobne aktivnosti, inhibirajići rast svih ispitivanh vrsta roda Lactobacillus, kao i patogenih bakterija Staphylococcus aureus i Salmonella abony. Bakteriocin G2 je osetljiv na proteolitičko dejstvo tripsina i proteinaze K. Antimikrobna aktivnost je stabilna u opsegu 40-60°C (15 min), ali se gubi na temperaturi od 80°C. Ustanovljeno je da je bakteriocin stabilan na pH vrednostima između 2 i 9. Dejstvo Tween-a 80 i uree je dovelo do povećane inhibitorne aktivnosti. Prema IEF, bakteriocin G2 je katjonski protein, sa pI vrednošću oko 10, a molekulaska masa određena na osnovu tricin-SDS-PAGE je 2,2 kDa. Probiotski soj L plantarum G2 produkuje antimikrobno jedinjenje proteinske strukture sa karakteristikama bakteriocina. Sinteza bakteriocina je jedna od ključnih osobina probiotskih bakterija koje imaju klinički potencijal kao antiinfektivni agensi, jer značajno povećava verovatnoću njihove in vivo efikasnosti.