Signalna uloga L-arginina u bakterija

undergraduate thesis

• Title (english): A signalling role of L-arginine in bacteria
• Author: Ana Madunić
• Mentor: Ita Gruić Sovulj (mentor)
• Granter: University of Zagreb; Faculty of Science; (Department of Biology); Zagreb
• Defense date and country: 2024-09-18, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Biology

Abstract

Prijenos signala je ključan stanični proces koji omogućava usklađivanje i reguliranje metabolizma u svim domenama života. Funkcionira na način da se izvanstanična signalna molekula veže za membranski receptor te potiče njegovu konformacijsku promjenu s citosolne strane što dalje inducira pokretanje enzimske kaskade i omogućava svrishodan stanični odgovor. Proteinogena aminokiselina L-arginin pokazala se kao važan bakterijski signal, pogotovo u indukciji gena virulencije patogenih bakterija, u čemu joj pomaže protein ArgR. Specifično, L-arginin potiče prelazak bakterija roda Pseudomonas na životni stil u zajednici uronjenoj u jedinstveni izvanstanični matriks zvanoj biofilm. U crijevnom patogenu enterohemoragičnoj Escherichia coli, L-arginin potiče ekspresiju gena virulencije i regulira ekspresiju domaćinskog prijenositelja L-arginina čime kontrolira apsorpciju ove aminokiseline u crijevima. To sugerira da L-arginin ima potencijalno važnu ulogu i u eukariotskoj borbi protiv patogenih bakterija, što je potvrđeno na mišjim peritonealnim makrofagima. Naime, povećana koncentracija egzogenog L-arginina znatno pojačava imunosni odgovor ovih makrofaga nakon njegove aktivacije lipopolisaharidima Gram-negativnih bakterija. Sve ovo navodi na zaključak da je L-arginin, uz kanonsku ulogu u izgradnji proteina, važan signal u molekularnom nadmetanju bakterijskih patogena i njihovih domaćina.

Abstract (english)

Biosignalling is a crucial cellular process which enables the coordination and regulation of metabolism in all three domains of life. An extracellular signal binds to a membrane receptor and triggers a conformational change on its cytosolic side, which induces the activation of an enzymatic cascade and an appropriate cellular response. The proteinogenic amino acid L-arginine is an important bacterial signal, particularly in the induction of pathogenic bacteria virulence genes, with the protein ArgR's help. Specifically, L-arginine promotes the transition of Pseudomonas bacteria towards biofilm formation – a bacterial community that shares an extracellular matrix. In the intestinal pathogen enterohemorrhagic Escherichia coli, L-arginine serves as the activator of virulence gene expression and regulates the abundance of the enterocyte L-arginine transporter, thus controlling intestinal absorption of this amino acid. This suggests that L-arginine might play an important role in the eukaryotic defence against pathogenic bacteria, which has been confirmed in murine peritoneal macrophages. In particular, high concentrations of exogenous L-arginine significantly enhance the immune response of macrophages activated by lipopolysaccharides of Gram-negative bacteria. The conclusion is that L-arginine is an important factor in the molecular power struggle between bacterial pathogens and their hosts.

• Keywords: ArgR; biofilm; imunost; patogenost
• Keywords (english): ArgR; biofilm; immunity; pathogenicity
• Language: croatian
• URN:NBN: urn:nbn:hr:217:924803
• Project: Number: IP-2022-10-1400; Title: Istraživanja aminoacil-tRNA-sintetaza kao antibiotskih meta i mehanizama kojima razvijaju rezistenciju; Title: Investigation of aminoacyl-tRNA syntetases as targets for antibiotics and how they develop resistance mechanisms; Acronym: ARSTARE; Leader: Ita Gruić-Sovulj; Jurisdiction: Croatia; Funder: Hrvatska zaklada za znanost; Funding stream: Research Projects
• Study programme: Title: Molecular Biology; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) molekularne biologije (sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) molekularne biologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2024-09-30 10:57:17