Characterization of the binding affinity and identification of potential inhibitors of type 3 fimbriae in Escherichia coli

Elizabeta Madzharova

Studenteropgave: Speciale


Bacterial adhesion is a critical step in bacterial pathogenesis and infections, essential for host colonization and subsequent development of a disease. A better understanding of the adhesion process is demanded to establish new strategies for treatment or prevention of microbial infections. Casein-derived peptides, due to their unique and diverse properties, have attracted considerable attention as good therapeutic candidates that can prevent bacterial adhesion. The aim of this thesis was to identify a receptor for the type 3 fimbrial adhesin MrkD, responsible for the type 3 fimbria adherence to the surfaces and to inves-tigate the potential inhibitory properties of casein peptides against fimbrial adherence. We investigated the binding affinities of type 3 fimbriae in E. coli toward cell-surface ex-pressed proteoglycans. We, further, investigated the inhibitory properties of the digested and fractioned casein and tryptone against agglutination between bacteria and yeast. Ca-sein digestion fragments were analyzed by liquid chromatography tandem mass spec-trometry (LC-MS/MS). Myoglobin and bovine serum albumin (BSA) were used for an es-tablishment of a standard trypsin digestion procedure and were analyzed by mass spec-trometry. The MS results revealed a number of peptides from myoglobin and BSA digest, but not from the casein digest. Moreover, the casein digest and tryptone did not inhibit the agglutination between bacteria and yeast. Additionally, E. coli harboring the MrkD adhesin did not show significant binding to different proteoglycans, whereas E. coli strain, lacking the mrkD adhesin exhibited high affinity towards cells, deficient in proteoglycan produc-tion. In conclusion, no inhibitory activity was associated with any of the tested casein pep-tides, as well as for the tryptone. Additionally, a receptor for the type 3 fimbria adhesin, MrkD, was not identified.

UddannelserKemi, (Bachelor/kandidatuddannelse) KandidatMolekylærbiologi, (Bachelor/kandidatuddannelse) Kandidat
Udgivelsesdato28 sep. 2016
Antal sider75
VejledereTorben Lund & Håvard Jenssen