Molekularna karakterizacija kvazivrsta hrvatskih izolata virusa hepatitisa A

master's thesis

• Title (english): Molecular characterization of Hepatitis A virus quasispecies from Croatian isolates
• Author: Josipa Kuzle
• Mentor: Silvija Černi (mentor)
• Mentor: Ivana Grgić (mentor)
• Committee member: Silvija Černi (predsjednik povjerenstva)
• Committee member: Duje Lisičić (član povjerenstva)
• Committee member: Jasna Lajtner (član povjerenstva)
• Committee member: Sofia Ana Blažević (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Biology); Zagreb
• Defense date and country: 2020-09-28, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Biology

Abstract

Virus hepatitisa A (HAV) jednolančani je RNA virus pozitivnog smisla iz porodice Picornaviridae i glavni uzročnik akutne bolesti jetre u svijetu. Broj zaraženih u Hrvatskoj porastao je u posljednjih nekoliko godina. Kao i ostali virusi s RNA-genomom, HAV ima tendenciju nakupljanja mutacija zbog brze replikacije i nemogućnosti popravaka pogrešaka enzima RNA-polimeraze ovisne o RNA. Zbog toga virusni izolati sadrže velik broj mutanata/genomskih varijanti, koje zajedno tvore tzv. kvazivrste. Varijante unutar kvazivrste mogu se razlikovati u svom patogenom potencijalu, no rutinske analize ne uključuju njihovu karakterizaciju. Gotovo nema literaturnih podataka o genskoj raznolikosti varijanti virusa HAV unutar pojedinih izolata te o prirodi prisutnih mutacija. Stoga je cilj ovog rada bio molekularno karakterizirati genomske varijante virusa HAV razdvojene kloniranjem, podrijetlom iz 13 pacijenata. Analizom hipervarijabilne regije genoma VP2-2A svakog uzorka obuhvaćeno je po 20 varijanti, koje su identificirane metodom SSCP i sekvencirane. Usporedbom virusnih mutanata s dominantnom populacijskom varijantom svakog uzorka utvrđena je brojnost i priroda mutacijskih događaja. Rezultati ukazuju na česte mutacijske događaje nasumično pozicionirane unutar analizirane regije. Detektiran je i visok postotak nesinonimnih mutacija, što može imati utjecaj na biološke karakteristike virusa. Kod pacijenata koinficiranih virusom HIV zabilježen je manji broj promjena na nukleotidnoj i aminokiselinskog razini u odnosu na ostale pacijente.

Abstract (english)

Hepatitis A virus (HAV) is a positive single-stranded RNA virus from Picornaviridae family. In Croatia number of people infected with HAV increased in recent years. As other RNA viruses, HAV tends to accumulate mutations due to rapid replication and error-prone nature of RNA-dependent RNA polymerase. Consequently, viral isolates contain large number of genomic variants, which together form so-called quasispecies. Different variants within quasispecies may differ in their pathogenic potential, but their characterization is not a part of routine analysis. There is almost no literature on quasispecies structure of HAV. The aim of this study was to molecularly characterize genomic variants, previously separated by cloning, from 13 patients. The analysis of VP1-2A hypervariable genomic region included 20 variants per sample, which were identified by SSCP method and sequenced. The number and nature of mutational events were determined by comparing nucleotide and amino-acid sequence of mutants with those of dominant population variant from each sample. The results indicate frequent mutations randomly positioned through the analysed region. High percentage of non-synonymous mutations was detected, that can have a significant impact on the virus biology. In comparison to others, in patients co-infected with HIV fewer nucleotide and amino acid changes was detected.

• Keywords: mutacije; populacijska struktura; sekvenciranje; SSCP
• Keywords (english): mutations; population structure; sequencing; SSCP
• Language: croatian
• URN:NBN: urn:nbn:hr:217:891678
• Study programme: Title: Experimental Biology; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra eksperimentalne biologije (magistar/magistra eksperimentalne biologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access; Embargo expiration date: 2022-09-28
• Created on: 2020-10-07 09:05:19