Vpliv zunajceličnih polimerov na mehanske in funkcionalne lastnosti biofilmov bakterije Escherichia coli

magistrsko delo

Maruša Horvat (Author), Darja Žgur-Bertok (Reviewer), David Stopar (Mentor)

Abstract

Mehansko stabilnost biofilmu daje zunajcelični matriks, ki zapolni prostor med bakterijskimi celicami in jih drži skupaj. V magistrski nalogi smo testirali, kako sprememba izražanja zunajceličnih polimerov matriksa pri biofilmih bakterije E. coli (PGA, kodri, kolanska kislina), vpliva na viskoznost in viskoelastičnost biofilma, pa tudi, kako vpliva na odpornost proti protimikrobnim sredstvom, specifično proti vodikovemu peroksidu. Dodatno smo testirali, kako dodatek vode oziroma detergenta SDS vpliva na viskoznost posameznih biofilmov. Ugotovili smo, da se viskoznost in viskoelastičnost biofilmov z različnim izražanjem zunajceličnih polimerov značilno razlikuje. Največji efekt na mehanske lastnosti biofilma je imela odsotnost proteinskih kodrov. Prekomerno izražanje kolanske kisline je zmanjšalo viskoznost, pseudoplastičnost in stabilnost biofilma. Odsotnost sinteze PGA, kodrov in kolanske kisline ni zavrla nastanka biofilma. Dodatek vode ali raztopine SDS je značilno omehčal biofilme. Učinkovitost delovanja vodikovega peroksida na celice v biofilmu se med sevi razlikuje. Po dovzetnosti za vodikov peroksid izstopa mutanta MG1655 csrA, ki prekomerno izraža PGA, pri kateri je bil vodikov peroksid znatno bolj učinkovit kot pri ostalih sevih. Kljub dostopnosti za vodikov peroksid niso propadle vse celice na površini.

Keywords

Escherichia coli;biofilmi;reološke lastnosti;viskoznost;viskoelastičnost;zunajcelični polimeri;vodikov peroksid;

Data

Language:	Slovenian
Year of publishing:	2018
Typology:	2.09 - Master's Thesis
Organization:	UL BF - Biotechnical Faculty
Publisher:	[M. Horvat]
UDC:	579.24/.26:579.842:544
COBISS:	4974968
Views:	1219
Downloads:	477
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	ǂThe ǂeffect of extracellular matrix polimers on mechanical and functional properties of Escherichia coli biofilms
Secondary abstract:	Biofilm mechanical stability is due to extracellular matrix, which fills the space between bacterial cells and binds them together. In this work we tested, how different expression of extracellular polimers in matrix in E. coli biofilms (PGA, curli, colanic acid) effects biofilm viscosity and viscoelasticity, as well as how it effects the resistance agains hydrogen peroxide. Additionally we tested the effect of adding water or detergents on biofilm viscosity. Results showed significant differences in viscosity and viscoelasticity among biofilms with different expression of extracellular polimers. The absence of proteinaceus curli had the greatest effect on mechanical properties. Overproducing of colanic acid significantly decreased viscosity, pseudoplasticity and also biofilm stability. In the absence of PGA, curli and colanic acid production, E. coli could still form a biofilm. Adding water or SDS solution significantly softened the biofims. The effect of hydrogen peroxide on bacterial cells was different among biofilms. MG1655 csrA mutant, which is overproducing PGA, showed the greatest susceptibility for hydrogen peroxide. Not all the cells in biofilm were killed by hydrogen peroxide.
Secondary keywords:	Escherichia coli;biofilms;rheological properties;viscosity;viscoelasticity;extracellular polimers;hydrogen peroxide;
Type (COBISS):	Master's thesis/paper
Study programme:	0
Thesis comment:	Univ. v Ljubljani, Biotehniška fak., Študij mikrobiologije
Pages:	X, 44 str., [3] str. pril.
ID:	10980005