Otpornost prema žučnim solima i antimikrobna aktivnost bakterija mliječne kiseline

undergraduate thesis

• Title (english): Bile Salt Resistance and Antimicrobial Activity of Lactic Acid Bacteria
• Author: Tena Dominko
• Mentor: Andreja Leboš Pavunc (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: 2017-07-07, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

Cilj ovog završnog rada bio je ispitati prisutnostfragmenatabsh gena, koji kodira za hidrolazu žučnih soli, kod bakterija mliječne kiseline Lactobacillus helveticus M92, L. brevis D6, L. brevis ZG1, L. brevis SF9B, L. brevis SF15B i L. plantarum D13. Naime, bakterije aktivnošću enzima hidrolaze žučnih soli mogu utjecati na regulaciju koncentracije kolesterola, a ujedno taj enzim može biti odgovoran za preživljavanje probiotičkih sojeva u gastrointestinalnom traktu gdje između ostalog, postoje nepovoljni uvjeti zbog žučnih soli. PCR reakcijom su fragmenti bsh gena potvrđeni kod sojeva Lactobacillus plantarum D13, L. brevis D6 i L. brevis SF9B. Probiotičke bakterije također imaju važnu ulogu u inhibiciji rasta potencijalno patogenih mikroorganizama, a to antimikrobno djelovanje je posljedica biosinteze raznih ekstracelularnih metabolita, među kojima su i bakteriocini. Stoga je u ovom radu dodatno ispitivana antimikrobna aktivnost soja Lactobacillus plantarum D13, metodom s dvostrukim slojem agara. Bakteriocinska aktivnost ispitivanog soja je inducirana kokultivacijom s test-mikroorganizmima L. monocytogenes ATCC 19111 i St. aureus 3048.Dodatkom žučnih soli, kao dodatnih stresnih okolišnih čimbenika za bakterije mliječne kiseline, dodatno je potaknuto bakteriocinsko djelovanje prema test-mikroorganizmu St. aureus 3048.

Abstract (english)

The aim of this study was to examine presence of bsh gene, encoding for bile salt hydrolase (BSH), in lactic acid bacteria strains Lactobacillus helveticus M92, L. brevis D6, L. brevis ZG1, L. brevis SF9B, L. brevis SF15B andL. plantarum D13. Probiotic bacteria can be involved in regulation of cholesterol level by BSH activity. At the same time, BSH actvity could be responsible for survival of probiotic strains in stressful gastrointestinal tract conditions, caused, amoung other, by bile salts. According to results of PCR reactions, bsh gene fragments were detected in Lactobacillus plantarum D13, L. brevis D6 and L. brevis SF9B strains. In addition, lactic acid bacteria have an important role in inhibition of growth of potentially pathogenic microorganisms. That antimicrobial activity is result of biosynthesis of various extracellular compounds,including bacteriocins. Hence, antimicrobial activity of Lactobacillus plantarum D13 strain was also examined by agar-spot-agar method. Bacteriocin activity was induced by cocultivation wtih test-microorganisms L. monocytogenes ATCC 19111 andSt. aureus 3048. Addition of bile salts, as additional stressful environmental condition, has furhter induced bacteriocin activity towards test-microorganism St. aureus 3048.

• Keywords: antimikrobna aktivnost; bakteriocini; hidrolaza žučnih soli; kokultivacija; Lactobacillus plantarum
• Keywords (english): antimicrobial activity; bacteriocins; bile salt hydrolase; cocultivation; Lactobacillus plantarum
• Language: croatian
• URN:NBN: urn:nbn:hr:159:328430
• Study programme: Title: Biotechnology; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka biotehnologije (sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka biotehnologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2017-07-10 07:12:57