Naslov
Induction of the bacteriocin biosynthesis by different probiotic strains after cocultivation with Lactococcus lactis subsp. lactis LMG 9450

Autori
Beganović, Jasna ; Leboš Pavunc, Andreja ; Kos, Blaženka ; Habjanič, Ksenija ; Šušković, Jagoda

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Proceedings of the International Scientific Conference on Probiotics and Prebiotics / - Košice, 2010

ISBN
978-80-970168-4-5

Skup
International Scientific Conference on Probiotics and Prebiotics

Mjesto i datum
Košice, Slovačka, 15.07.2010. - 17.07.2010

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
antibacterial activity; bacteriocins; coaggregation; probiotics

Sažetak
Introduction: Bacteriocin biosynthesis by probiotic strains can contribute to the colonisation resistance of the host, its protection against gastrointestinal pathogens and facilitate the establishment of a probiotic strain in the competitive environment of the gut. The presence and close contact of competing microorganism has been reported to be an environmental factor affecting bacteriocin biosynthesis by LAB. Additionally, coaggregation abilities of probiotic bacteria may form a barrier that prevents colonisation of gastrointestinal tract by pathogenic microorganisms. Methods: Hence, in this study, the production of antimicrobial substances with the special interest for bacteriocin biosynthesis of probiotic strains Lactobacillus helveticus M92, Lactobacillus plantarum L4, Enterococcus faecium L3, Enterococcus faecium A7 and Lactobacillus fermentum A8, was examined. Antimicrobial activity of these probiotic strains against different test microorganisms and against representatives of the same and related bacterial species, what indicates on their bacteriocin activity, was tested, too. The possibility to induce bacteriocin biosynthesis after cocultivation of probiotic strains with Lactococcus lactis subsp. lactis LMG 9450 cells, either live or inactivated by boiling at 100 ºC, was researched, as well as ability of Lact. lactis subsp. lactis LMG 9450 supernatant to induce bacteriocin production. Currently the presence of the several genes from different bacteriocins clusters is investigated by PCR amplification with specific primers. Furthermore, coaggregation of the probiotic strains with different test microorganisms, as additional mechanism of competence in the GIT, with the special focus on the role of S-layer proteins in these interactions, was performed. Results: All probiotic strains have shown strong antimicrobial activity which is an important functional characteristic and one of the crucial mechanisms for competitive exclusion which provides probiotic strains selective advantage against pathogen microorganisms in a specific microenvironment of gastrointestinal tract. After the cocultivation with Lact. lactis subsp. lactis LMG 9450, the strong inhibitory activity of cell free supernatants with pH adjusted at 6.5 of probiotic strains: L. plantarum L4 and L. helveticus M92 against all test microorganisms ; E. faecium L3 against E. coli 3014, S. Typhimurium FP1 and B. subtilis ATCC 6633 ; E. faecium A8 against E. coli 3014, S. aureus K-144 and B. subtilis ATCC 6633. Additionally, L. helveticus M92 has shown strong antibacterial activity against L. plantarum L4, while E. faecium L3 and E. faecium A7 inhibited L. helveticus M92 and L. plantarum L4. L. helveticus M92 and L. fermentum A8 have shown strong coaggregation ability with Salmonella enterica s. Typhimurium FP1. The results confirmed that L. helveticus M92 surface (S) -layer proteins are responsible for the highest coaggregation with S. Typhimurium FP1. Discussion: The obtained results propose that living cells of Lact. lactis subsp. lactis LMG 9450 could induce bacteriocin production by examined probiotic strains. This induction did not take place when Lact. lactis subsp. lactis LMG 9450 cells were boiled or with cell-free supernatant. The use of bacteriocin-producing LAB, both as starters or probiotics which coaggregate with pathogens, may contribute to food safety and facilitate competitive advantage of the probiotic strain in GIT environment.

Izvorni jezik
Engleski

Znanstvena područja
Biotehnologija

POVEZANOST RADA