Epizoičke dijatomeje roda Poulinea na glavatim želvama iz Jadranskog mora

master's thesis

• Title (english): Epizoic diatom genus Poulinea from loggerhead sea turtles in the Adriatic Sea
• Author: Lucija Kanjer
• Mentor: Sunčica Bosak (mentor)
• Committee member: Sunčica Bosak (predsjednik povjerenstva)
• Committee member: Romana Gračan (član povjerenstva)
• Committee member: Tomislav Ivanković (član povjerenstva)
• Committee member: Marija Gligora Udovič (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Biology); Zagreb
• Defense date and country: 2020-02-17, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Biology

Abstract

Genus Poulinea is a monospecific epizoic genus of marine diatoms found on sea turtles. It is a part of polyphyletic group of marine gomphonemoids, whose phylogenetical relationships are poorly understood. The aim of this study was to use a combined morphological and molecular approach to investigate Poulinea and related genera on loggerhead sea turtles from the Adriatic Sea. Firstly, the contribution of Poulinea cells in diatom epizoic communities was assessed using light microscope from seven loggerhead samples obtained in the period 1995-2004. Further on, morphology and morphometrics of Poulinea-like cells was assessed on scanning electron microscopy images taken from the first sample set with the addition of 31 loggerhead samples obtained from 2016 to 2019. Lastly, three strains of Poulinea were brought into laboratory cultures and information on their morphology and rbcL, psbC and SSU genes were obtained. Poulinea was recorded as a dominant taxon in the epizoic flora on the Adriatic loggerheads. However, four morphological groups of cells could be distinguished in the population of the Poulinea-like diatoms with only a single morphotype corresponding to the type species Poulinea lepidochelicola, while other groups showed higher variability and were generally more similar to Chelonicola spp. The phylogenetic analyses place all three cultured strains closely to other Poulinea lepidochelicola strains. This research offers new insights into the morphology and phylogeny of Poulinea and related taxa and sheds more light on the ecology of these small and poorly known epibionts.

Abstract (croatian)

Rod Poulinea je monospecifični rod dijatomeja koje žive na morskim kornjačama. Rod Poulinea spada u polifiletsku skupinu morskih epizoičkih gomfonemoidnih dijatomeja o kojoj nedostaju podaci o filogenetskim odnosima. Cilj ovog rada je kombiniranjem morfološkog i molekularnog pristupa istražiti rod Poulinea i srodne svojte na glavatim želvama iz Jadranskog mora. Relativna brojnost roda Poulinea u zajednici dijatomeja je istražena iz sedam uzoraka kože želvi prikupljenih u periodu 1995.-2004. koristeći svjetlosni mikroskop. Morfološke analize su napravljene na slikama skenirajućeg elektronskog mikroskopa koje su dobivene iz prvog seta uzoraka uz dodatak 31 uzorka sakupljenog u periodu 2016.-2019. Uzgojene su tri laboratorijske kulture vrste Poulinea lepidochelicola čija je morfologija analizirana te sekvencirani rbcL, psbC i SSU geni. Rezultati su pokazali da su dijatomeje roda Poulinea dominantne u epizoičkoj flori na jadranskim glavatim želvama. Međutim, morfološke analize su odvojile četiri različite grupe stanica, samo jedna morfološki odgovara tipskoj vrsti Poulinea lepidochelicola, dok ostale grupe pokazuju veću morfološku varijabilnost i sličnije su vrstama roda Chelonicola. Tri izolirane kulture prema morfologiji i filogeniji jasno se grupiraju s ostalim pripadnicima vrste P. lepidochelicola iz drugih krajeva svijeta. Ovo istraživanje nudi nove uvide u morfologiju i filogeniju roda Poulinea i poznavanje ekologije ovih malih i slabo poznatih epibionata.

• Keywords: epibiont; Bacillariophyta; Caretta caretta; polyphasic approach; morphology; phylogeny; culturing
• Keywords (english): epibiont; Bacillariophyta; Caretta caretta; polifazni pristup; morfologija; filogenija; kulture
• Language: english
• URN:NBN: urn:nbn:hr:217:826690
• Study programme: Title: Ecology; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra ekologije i zaštite prirode (magistar/magistra ekologije i zaštite prirode)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access; Embargo expiration date: 2021-02-17
• Created on: 2020-06-09 09:58:41