Utjecaj mistranslacije i oksidacijskog stresa na bakteriju Escherichia coli

master's thesis

• Title (english): Influence of mistranslation and oxidative stress on bacteria Escherichia coli
• Author: Marko Prosinečki
• Mentor: Jasmina Rokov Plavec (mentor)
• Committee member: Jasmina Rokov Plavec (predsjednik povjerenstva)
• Committee member: Đani Škalamera (član povjerenstva)
• Committee member: Vladimir Stilinović (član povjerenstva)
• Committee member: Vesna Petrović Peroković (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Chemistry); Zagreb
• Defense date and country: 2023-02-24, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry

Abstract

Translacija je stanični proces biosinteze proteina prema zapisu genetičke informacije u mRNA. Razina ugradnje pogrešne aminokiseline, odnosno mistranslacija, može se razlikovati u različitim organizmima i pri različitim uvjetima. Novija istraživanja pokazala su da povećana razina mistranslacije može imati pozitivan učinak na odgovor stanice na drugi stres. Istraživanje adaptacije na oksidacijski stres je značajno zato što je oksidacijski stres dio odgovora imunološkog sustava domaćina kojim ubija patogene bakterije. Prethodno je pripremljen soj bakterije Escherichia coli s nefunkcionalnom domenom za popravak pogreške izoleucil-tRNA-sintetaze što omogućuje povećanu specifičnu mistranslaciju izoleucina strukturno sličnim aminokiselinama valinom (Val) ili norvalinom (Nva). Praćen je rast ovog soja i uočeno je da uslijed prethodne mistranslacije dolazi do predaptacije stanica na oksidacijski stres. Preadaptacija može biti povezana s općim odgovorom stanice na stres, u kojem središnju ulogu ima protein RpoS, sigma faktor RNA-polimeraze. U svrhu utvrđivanja važnosti proteina RpoS u preadaptaciji stanice uslijed mistranslacije na oksidacijski stres pripremljen je mistranslatirajući soj s inaktiviranim genom rpoS. Rezultati upućuju da RpoS ima esencijalnu ulogu u obrani stanice od oksidacijskog stresa za bakterije koje su prethodno uzgajane pri nižim koncentracijama Val ili Nva dok pokazuje potpornu ulogu za bakterije koje su prethodno uzgajane pri višim koncentracijama Val ili Nva. Izgleda da u uvjetima povišene mistranslacije (više koncentracije Val ili Nva) bakterije pokreću dodatne mehanizme koji ne ovise samo o RpoS regulonu, a koji su dovoljni za preživljenje u oksidacijskom stresu.

Abstract (english)

Translation is a cellular process of protein biosynthesis according to the genetic information in mRNA. The level of incorporation of the incorrect amino acid, or mistranslation, can differ in different organisms and under different conditions. More recent research has shown that increased levels of mistranslation can have a positive effect on the cell's response to other stresses. Research on adaptation to oxidative stress is significant because oxidative stress is part of the host's immune system response to kill pathogenic bacteria. Previously, a strain of Escherichia coli bacteria was prepared with a nonfunctional isoleucyl-tRNA-synthetase editing domain, which enables increased specific mistranslation of isoleucine to structurally similar amino acids valine (Val) or norvaline (Nva). The growth of this strain was monitored and it was observed that, due to the previous mistranslation, pre-adaptation of the cells to oxidative stress occurs. Preadaptation can be related to the general response of the cell to stress, in which the protein RpoS, the sigma factor of RNA polymerase, plays a central role. In order to determine the importance of the RpoS protein in the pre-adaptation of cells due to mistranslation to oxidative stress, a mistranslating strain with an inactivated rpoS gene was prepared. The results suggest that RpoS plays an essential role in the defense of the cell against oxidative stress for bacteria precultured at lower concentrations of Val or Nva while it shows a supportive role for bacteria pre-cultured at higher concentrations of Val or Nva. It seems that under conditions of elevated mistranslation (higher concentration of Val or Nva), bacteria trigger additional mechanisms that do not depend only on the RpoS regulon, and which are sufficient for survival in oxidative stress.

• Keywords: izoleucil-tRNA-sintetaza; mistranslacija; oksidacijski stres; RpoS
• Keywords (english): isoleucyl-tRNA-synthetase; mistranslation; oxidative stress; RpoS
• Language: croatian
• URN:NBN: urn:nbn:hr:217:833379
• Study programme: Title: Graduate university studies in chemistry; specializations in: Research programme; Course: Research programme; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra kemije (magistar/magistra kemije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2023-03-22 12:27:10