Adhezijska svojstva potencijalnih probiotičkih sojeva bakterija mliječne kiseline

master's thesis

• Title (english): Adhesion properties of potential probiotic strains of lactic acid bacteria
• Author: Tomislav Korman
• Mentor: Jagoda Šušković (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Biochemical Engineering); (Laboratory for Antibiotic, Enzyme, Probiotic and Starter Cultures Technology); Zagreb
• Defense date and country: 2012-01-27, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

Prilikom odabira probiotičkih sojeva, jedan od najvažnijih kriterija je sposobnost pojedine bakterije da adhezira i kolonizira gastrointestinalni trakt (GIT) domaćina. Probiotičke bakterije pri tom se natječu za mjesta vezanja u GIT domaćina s patogenim bakterijama što može doprinijeti zaštiti od infekcija. Stoga su u ovom radu ispitana adhezijska svojstva potencijalnih probiotičkih sojeva bakterija mliječne kiseline (BMK) izoliranih iz autohtonih svježih sireva, te je ispitano njihovo antimikrobno djelovanje. Prema dobivenim rezultatima, adhezija sojeva BGG07-25 i BGG011-17 pokazala se uspješnom. Ispitana je i antimikrobna aktivnost supernatanata kultura autohtonih izolata prema bakteriji Salmonella enterica serovar. Typhimurium FP1. Inhibicijsko djelovanje autohtonih izolata BMK prema S. Typhimurium FP1 osobito je bilo izraženo kada je pH vrijednost supernatanta kulture bila u kiselom području, dok su supernatanti kultura, autohtonih izolata BGAL1-1, BGAL1-14, BGAL1-39 i BGLE1-6 uspješno inhibirali rast S. Typhimurium FP1 i kada je pH vrijednost supernatanta kulture podešena na 6,5, odnosno kada je uklonjen inhibicijsku učinak mliječne kiseline, što može upućivati na bakteriocinsku aktivnost. Jedan od ciljeva ovog rada je bio ispitati funkcionalnu ulogu površinskih S-layer proteina u adheziji probiotičkih bakterija, kod kojih je dokazana prisutnost S-layer proteina, na Caco-2 epitelne stanice, jer su prema literaturi ovi proteini važni čimbenici u adheziji pojedinih Lactobacillus sojeva.

Abstract (english)

One of the key selection criteria for potential probiotics is ability to adhere and colonise gastrointestinal tract (GIT). Probiotics compete for receptor sites at host intestinal surface, preventing colonisation of pathogens, thereby protecting the host from infection.Therefore, this work examines the adhesion capacity of the potential probiotic strains of lactic acid bacteria (LAB) isolated from autochthonous fresh cheese, as well as their antimicrobial activity. According to the obtained results, adhesion of the strains BGG07-25 and BGG011-17 proved to be the most successful. Additionally, the antimicrobial activity of culture supernatants of the autochthonic isolates culture supernatants against the bacterium Salmonella enterica serovar. Typhimurium FP1 was examined. S. Typhimurium FP1 growth inhibition by the autochthonious LAB isolates was especially strong when pH levels of the culture supernatants were acidic, whilst the culture supernatants of autochthonic isolates BGAL1-1, BGAL1-14, BGAL1-39 and BGLE1-6 successfully inhibited the growth of S. Typhimurium FP1 even when the pH values of the culture supernatants were adjusted to 6,5, in order to eliminate the inhibition effects of the produced lactic acid, which could indiceted on potential bacteriocinogenic activity. One of the aims of this work was to examine the functional role of the surface S-layer proteins in adhesion to the probiotic bacteria because these proteins are reported as adhesins in some Lactobacillus strains.

• Keywords: adhezija; Caco-2 epitelne stanice; autohtone bakterije mliječne kiseline; S-layer protein; S. Typhimurium FP1
• Keywords (english): adhesion; Caco-2 epithelial cells; autochtchonous lactic acid bacteria; S-layer protein; S. Typhimurium FP1
• Language: croatian
• URN:NBN: urn:nbn:hr:159:106132
• Study programme: Title: Biotechnology; specializations in: Biochemical Engineering; Course: Biochemical Engineering; Study programme type: university; Study level: graduate; Academic / professional title: diplomirani inženjer biotehnologije; smjer biokemijsko inženjerstvo (diplomirani inženjer biotehnologije; smjer biokemijsko inženjerstvo)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2017-05-17 10:53:51