magistrsko delo
Simon Huzjak (Author), Anja Klančnik (Reviewer), Iztok Dogša (Mentor)

Abstract

V magistrski nalogi smo preverjali odpornost bakterij Bacillus subtilis v biofilmu proti protimikrobnim sredstvom in mehanskem stresu ter se pri tem usmerili tudi v ugotavljanje prispevka k odpornosti zaradi prisotnega proteina TasA in zunajceličnih polisaharidov EpsA-O. V prvem delu smo z uporabo modularnega oscilacijskega reometra določali osnovne reološke lastnosti biofilmov različnih mutantov, kot so elastični in viskozni modul, kohezivna energija ter faktor dušenja. Za določanje odpornosti proti protimikrobnim sredstvom smo celice obarvali s propidijevim jodidom in jih izpostavili antibiotikom daptomicinu, eritromicinu in vankomicinu ter spremljali njihovo živost s pomočjo merjenja fluorescence propidijeva jodida. Na podoben način smo določevali tudi odpornost proti mehanskemu stresu, ki smo ga izvajali s pomočjo ultrazvočnega sonikatorja. Rezultati kažejo, da lahko k zadrževanju vode v biofilmu in njegovi zaščiti proti protimikrobnim sredstvom, kot je antibiotik daptomicin, pripišemo pomembno vlogo proteinu TasA in zunajceličnim polisaharidom. Slednji pa so pomembni tudi pri ohranjanju konsistence biofilma in zaščiti celic v njem. Izpostavimo lahko tudi, da so bili antibiotiki, ki delujejo na celični metabolizem, v zrelem biofilmu neučinkoviti.

Keywords

mikroorganizmi;Bacillus subtilis;biofilm;protimikrobne snovi;odpornost;mehanski stres;antibiotiki;sonikacija;

Data

Language: Slovenian
Year of publishing:
Typology: 2.09 - Master's Thesis
Organization: UL BF - Biotechnical Faculty
Publisher: [S. Huzjak]
UDC: 579.24/.26:579.852.11
COBISS: 208969987 Link will open in a new window
Views: 51
Downloads: 9
Average score: 0 (0 votes)
Metadata: JSON JSON-RDF JSON-LD TURTLE N-TRIPLES XML RDFA MICRODATA DC-XML DC-RDF RDF

Other data

Secondary language: English
Secondary title: Resistance of Bacillus subtilis biofilms to antimicrobial agents and mechanical stress
Secondary abstract: The purpose of the master's thesis was testing the resistance of bacteria Bacillus subtilis in biofilm against antimicrobial agents and mechanical stress with the main focus on finding out the importance of protein TasA and exopolysaccharides EpsA-O. In the first part, using a modular oscillatory rheometer, we determined the basic rheological properties of biofilms of various mutants, such as elastic and viscous modulus, cohesive energy, and damping factor. To test the resistance against antimicrobial agents, we added propidium iodide as a viability stain and then we treated wild type and mutant strains deficient in exopolymer production with antibiotics daptomycin, erythromicin or vankomycin. The antibiotics’ efficiency was then evaluated by spectrofluorometry. Very similarly, we tested the resistance against mechanical stress by the use of ultrasound disintegrator. The results obtained during the experiments indicate that the retention of water in the biofilm and its protection against antimicrobial agents, such as the antibiotic daptomycin, can be attributed to the important role of the TasA protein and exopolysaccharides. The latter are also important for maintaining the consistency of the biofilm and protecting cells within it. Equally important is the finding that antibiotics targeting cellular metabolism were entirely ineffective against mature biofilm.
Secondary keywords: microorganisms;Bacillus subtilis;biofilms;resistence;antimicrobial agents;mechanical stress;antibiotics;sonication;
Type (COBISS): Master's thesis/paper
Study programme: 0
Thesis comment: Univ. v Ljubljani, Biotehniška fak., Oddelek za mikrobiologijo
Pages: 1 spletni vir (1 datoteka PDF (XII, 35 str., [7] f. pril.))
ID: 25170678