Karakterizacija tirozinaze u stigobiontskom rodu školjkaša Congeria Partsch, 1835 i njegovim nadzemnim srodnicima

master's thesis

• Title (english): The characterization of tyrosinase in stygobiotic bivalve genus Congeria Partsch, 1835 and its surface relative
• Author: Karlo Radečić
• Mentor: Helena Ćetković (mentor)
• Mentor: Damjan Franjević (mentor)
• Committee member: Damjan Franjević (predsjednik povjerenstva)
• Committee member: Vlatka Zoldoš (član povjerenstva)
• Committee member: Zlatko Liber (član povjerenstva)
• Committee member: Goran Klobučar (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Biology); Zagreb
• Defense date and country: 2019-02-18, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Biology

Abstract

Rod Congeria s tri recentne opisane vrste koje žive u podzemlju dinarskog krša jedina je stigobiontska svojta školjkaša na svijetu. Za razliku od nadzemnih srodnika, ovi su školjkaši izgubili pigmentaciju tkiva, što je obilježje mnogih podzemnih životinja. Molekularna osnova gubitka pigmentacije u životinja slabo je poznata. Cilj je ovog rada identificirati molekularnu osnovu gubitka pigmentacije u tri vrste stigobiontske svojte Congeria uspoređivanjem primarne strukture DNA i proteina njihovih homologa tirozinaze s onima dvaju nadzemnih (Dreissena, Mytilopsis) rodova porodice školjkaša Dreissenidae. Iz literature je poznato da je tirozinaza važan enzim za pigmentaciju školjkaša te da katalizira prvi korak u biosintezi melanina. Sekvence tirozinaze školjkaša porodice Dreissenidae dobivene su pretragom ranije sekvenceniranog transkriptoma korištenjem alata PIA (filogenetički obaviještena anotacija) te sekvenciranjem produkata, fragmenata homologa tirozinaze, umnoženih lančanom reakcijom polimerazom. Spektrofotometrijskom analizom provjerena je aktivnost enzima fenoloksidaza, kojima pripada tirozinaza, te je provedena filogenetička analiza tirozinaze u ovoj porodici. Osobitosti sekvenci tirozinaze vrste Congeria jalzici u odnosu na ostale svojte te manja aktivnost fenoloksidaza u odnosu na nadzemnog srodnika (Dreissena) pokazuju da je gubitak pigmentacije u ove svojte možda posljedica mutacijskih promjena u tirozinazi što je važan doprinos razumijevanju gubitka pigmentacije u drugih podzemnih životinja osim modelnog organizma – meksičke tetre (Astyanax mexicanus).

Abstract (english)

Genus Congeria with three exctanct species which live in the subterranean habitats of the Dinaric karst is the only stygobiotic taxon of bivalves. Unlike its surface relatives, these bivalves lost tissue pigmentation, which is feature that many subterranean animals have in common. The molecular causes of the loss of pigmentation in animals is scarcely known. The aim of this research is to identify molecular cause of the loss of pigmentation in genus Congeria by conmparing primary structure of DNA and protein homologues of tyrosinase between stygobiotic and two surface genera (Dreissena, Mytilopsis) of the bivalve family Dreissenidae. It is known in literature that tyrosinase is an enzyme important for pigmentation in bivalves and that it catalyses the first step in the biosynthesis of melanine. The sequences of tyrosinase of bivalves of the family Dreissenidae were found by searching the transcriptome (sequenced before) using tool called PIA (phylogenetically-informed annotation) and by sequencing products, fragments of tyrosinase homologs, amplified using polymerase chain reaction (PCR). The enzymatic activity of phenoloxidases, to which tyrosinase belongs, was tested by spectrophotometric analysis. The pyhlogenetic analysis of tyrosinases of this bivalve family was also performed. The unique features of tyrosinase sequences of Congeria jalzici in comparison to other members of the family and the lower phenoloxidase activity, compared to surface-living Dreissena, show that the loss of pigmentation in this species is possibly the consequence of mutations in tyrosinase. This is important contribution to understanding the loss of pigmentation of subterranean animals outside the model organism – the Mexican tetra (Astyanax mexicanus).

• Keywords: gubitak pigmentacije; podzemne životinje; mutacije; filogenetička analiza; evolucija
• Keywords (english): loss of pigmentation; subterranean animals; mutations; phylogenetic analysis; evolution
• Language: croatian
• URN:NBN: urn:nbn:hr:217:098125
• 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
• Created on: 2019-12-04 09:32:26