diplomsko delo
Zala Perko (Author), Marko Novinec (Mentor)

Abstract

Hiter razvoj odpornosti bakterij proti klasičnim antibiotikom zaradi njihove pretirane in nepravilne uporabe je v veliko breme svetovnemu zdravstvenemu sistemu. V okviru diplomske naloge smo iskali protimikrobne učinkovine proti trem organizmom, ki pripadajo akronimu ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa in rod Enterobacter) in jih je svetovna zdravstvena organizacija uvrstila na seznam najbolj kritičnih patogenov. Zaradi napredujočih mehanizmov odpornosti ti povzročajo težko ozdravljive okužbe, zato je zanje ključno odkrivanje novih antibiotikov. S presejalnimi testi so predhodno identificirali dva derivata hidroksinaftojske kisline, 3-hidroksi-2-naftojsko kislino s protimikrobno aktivnostjo proti bakterijam S. aureus in Escherichia coli ter [(4-kloro-1-hidroksinaftalen-2-karbonil)amino]-2-metilpropanojsko kislino, ki je inhibirala rast S. aureus. V okviru diplomskega dela smo zato želeli preveriti protimikrobne lastnosti serije derivatov hidroksinaftojske kisline, ki so strukturno podobni izhodiščnim spojinam, in najbolj učinkovito med njimi uporabiti kot izhodišče za sintezo spojin z izboljšano protimikrobno aktivnostjo. Naš cilj je bil tudi identificirati proteinske tarče 1-hidroksi-2-naftojske kisline v topni frakciji lizata S. aureus z afinitetno kromatografijo na nosilcu z ustreznim derivatom te spojine. Naši rezultati so pokazali, da serija malih molekul selektivno inhibira rast grampozitivnih bakterij S. aureus in Bacillus thuringiensis, ne pa tudi rasti gramnegativnih bakterij E. coli in P. aeruginosa. Ugotovili smo, da ima [(1-hidroksinaftalen-2-karbonil)amino]-2-metilpropanojska kislina širši spekter delovanja kot njen klorirani derivat, saj inhibira rast obeh grampozitivnih vrst. Izmed komercialno dostopnih derivatov smo nadalje okarakterizirali dve spojini in najnižjo vrednost minimalne inhibitorne koncentracije 125 μg/mL določili za 7-bromo-3-hidroksi-2-naftojsko kislino proti B. thuringiensis. Pri sintezi liganda za afinitetno kromatografijo smo ugotovili, da uvedba alkilne skupine preko amidne vezi sicer izboljša protimikrobno aktivnost spojine, a hkrati močno zmanjša njeno topnost. Z uporabo afinitetne kromatografije smo ugotovili, da se na ligand specifično veže 25 kDa velik protein. Tega nam v okviru diplomskega dela ni uspelo identificirati, zato njegova identifikacija ostaja cilj nadaljnjih raziskav.

Keywords

odpornost proti antibiotikom;razvoj novih antibiotikov;naftalenski derivati;hidroksinaftojska kislina;biološka aktivnost;afinitetna kromatografija;diplomska dela;

Data

Language: Slovenian
Year of publishing:
Typology: 2.11 - Undergraduate Thesis
Organization: UL FKKT - Faculty of Chemistry and Chemical Technology
Publisher: [Z. Perko]
UDC: 577.18:547.655(043.2)
COBISS: 153310211 Link will open in a new window
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Other data

Secondary language: English
Secondary title: Antimicrobial activity and protein target identification of selected hydroxynaphthoic acid derivatives
Secondary abstract: The rapid development of bacterial resistance to conventional antibiotics due to overuse and misuse is a major burden on the global healthcare system. In this thesis, we searched for antimicrobial agents against three organisms included in the acronym ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and the genus Enterobacter), which are listed by the World Health Organisation as the most critical pathogens causing difficult-to-treat infections due to emerging resistance mechanisms. Therefore, the discovery of new antibiotics is urgently needed. Two hydroxynaphthoic acid derivatives, 3-hydroxy-2-naphthoic acid with antimicrobial activity against S. aureus and Escherichia coli and 2-[(4-chloro-1-hydroxynaphthalene-2-carbonyl)amino]-2-methylpropanoic acid, which inhibits the growth of S. aureus, were previously identified by screening tests. The aims of this diploma thesis were to screen the antimicrobial properties of a series of hydroxynaphthoic acid derivatives structurally related to the initial hits, identify the most potent compound, and use it as a starting point for the synthesis of compounds with improved antimicrobial activity. We also aimed to identify protein targets of 1-hydroxy-2-naphthoic acid in the soluble fraction of S. aureus lysate by affinity chromatography on an immobilised derivative of this compound. Our results showed that the series of small molecules selectively inhibited the growth of the Gram-positive bacteria S. aureus and Bacillus thuringiensis, but not the growth of the Gram-negative bacteria E. coli and P. aeruginosa. We found that [(1-hydroxynaphthalene-2-carbonyl)amino]-2-methylpropanoic acid has a broader spectrum of activity than its chlorinated derivative, inhibiting the growth of both Gram-positive species. Among the commercially available derivatives, two compounds were further characterised, and a minimum inhibitory concentration of 125 μg/mL for 7-bromo-3-hydroxy-2-naphthoic acid against B. thuringiensis was determined. In the synthesis of the affinity ligand, it was found that the introduction of an alkyl group via an amide bond, while improving the antimicrobial activity, significantly reduced the solubility of the compound. Using affinity chromatography, we found that a 25 kDa protein specifically binds to the ligand. We were not able to identify this protein within the framework of the diploma thesis, so that its identification remains as the goal of further research.
Secondary keywords: antibiotics;resistance;hydroxynaphthoic acid;affinity chromatography;Antibiotiki;Naftalen;Univerzitetna in visokošolska dela;
Type (COBISS): Bachelor thesis/paper
Study programme: 1000371
Embargo end date (OpenAIRE): 1970-01-01
Thesis comment: Univ. v Ljubljani, Fak. za kemijo in kemijsko tehnologijo, UNI Biokemija
Pages: 46 str.
ID: 18873808