In vitro adhezija bakterija mliječne kiseline iz majčinog mlijeka

master's thesis

• Title (english): In vitro adhesion of lactic acid bacteria from human breast milk
• Author: Valentina Ribić
• Mentor: Andreja Leboš Pavunc (mentor)
• Committee member: Blaženka Kos (predsjednik povjerenstva)
• Committee member: Jasna Mrvčić (član povjerenstva)
• Committee member: Ksenija Durgo (član povjerenstva)
• 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: 2022-09-23, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

Cilj ovog rada bio je in vitro ispitati adhezijska i probiotička svojstva sojeva bakterija mliječne kiseline izoliranih iz majčinog mlijeka. Ispitana su svojstva sojeva Levilactobacillus brevis MB13 i MB20 kroz eksperimente adhezije na Caco-2 stanice i na proteine ekstracelularnog matriksa te ispitivanjem preživljavanja u simuliranim uvjetima gastrointestinalnog trakta (GIT) pri čemu je istovremeno ispitana i uloga S-proteina u adheziji i zaštiti od nepovoljnih uvjeta. Također, eksperimentom kompetitivne ekskluzije ispitano je djelovanje sojeva L. brevis MB13 i MB20, Limosilactobacillus fermentum MC1 te Lactiplantibacillus plantarum MC19 i KR19 prema patogenoj vrsti Salmonella enterica serovar Typhimurium FP1. Provedenim eksperimentima dokazano je da sojevi L. brevis MB13 i MB20 posjeduju adhezijska svojstva i mogu preživjeti nepovoljne uvjete GIT-a, međutim za to je odgovoran S-sloj proteina čije uklanjanje uzrokuje značajno smanjenje adhezije te nemogućnost preživljavanja u GIT-u. Također, kompetitivnom ekskluzijom dokazano je da svi ispitani sojevi imaju antimikrobno djelovanje prema S. enterica serovar Typhimurium FP1.

Abstract (english)

The aim of this work was to test in vitro the adhesion and probiotic properties of lactic acid bacteria strains isolated from human breast milk. The properties of Levilactobacillus brevis strains MB13 and MB20 were tested through experiments of adhesion on Caco-2 cells and extracellular matrix proteins and survival tests in simulated conditions of the gastrointestinal tract (GIT), at the same time the role of S-protein in adhesion and protection against adverse conditions was tested. Also, the activity of L. brevis MB13 and MB20, Limosilactobacillus fermentum MC1, Lactiplantibacillus plantarum MC19 and KR19 strains against the pathogenic species Salmonella enterica serovar Typhimurium FP1 was tested using a competitive exclusion experiment. The conducted experiments proved that L. brevis strains MB13 and MB20 possess adhesive properties and can survive unfavorable conditions of the GIT, however, the S-layer protein is responsible for this, the removal of which causes a significant reduction in adhesion and the inability to survive in the GIT. Also, competitive exclusion proved that all tested strains have antimicrobial activity against S. enterica serovar Typhimurium FP1.

• Keywords: probiotičke bakterije; majčino mlijeko; adhezijska svojstva; S-sloj proteina
• Keywords (english): probiotic bacteria; human breast milk; adhesion properties; S-layer
• Language: croatian
• URN:NBN: urn:nbn:hr:159:327279
• Study programme: Title: Bioprocess Engineering; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka bioprocesnog inženjerstva (magistar/magistra inženjer/inženjerka bioprocesnog inženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2023-03-15 12:13:37