DIVERSITY OF DIATOM AND BACTERIAL COMMUNITIES ASSOCIATED WITH LOGGERHEAD SEA TURTLES (CARETTA CARETTA)

doctoral thesis

• Title (croatian): RAZNOLIKOST MIKROBNIH ZAJEDNICA DIJATOMEJA I BAKTERIJA GLAVATIH ŽELVI (CARETTA CARETTA)
• Author: Klara Filek
• Mentor: Sunčica Bosak (mentor)
• Committee member: Tomislav Ivanković (predsjednik povjerenstva)
• Committee member: Zrinka Ljubešić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Biology); Zagreb
• Defense date and country: 2022-11-29, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Biology
• Universal decimal classification (UDC): 57 - Biological sciences. Physical anthropology. Biodiversity

Abstract

Loggerhead sea turtles are ancient marine reptiles inhabiting the oceans worldwide. They are
colonized by microorganisms both in the gastrointestinal tract and on their carapace and skin.
In this thesis that consists of four scientific publications, the loggerhead sea turtle-associated
diatom and bacterial communities were investigated by high-throughput sequencing of
chloroplast rbcL gene and 16S rRNA gene, and cultivation. The culture-independent approach
has shown that loggerheads harbor diverse but stable bacterial communities in their cloaca, and
that the oral microbiota reflects the turtle’s environment. The carapace and skin harbor complex
microbial communities often rich in as yet unclassified taxa. Diatoms isolated from carapace
and skin were cultivated as xenic monocultures and further characterized using morphology
and molecular techniques to elucidate their identity and phylogeny. Novel diatom taxa were
discovered, often belonging to the genera Craspedostauros, Fallacia, or Amphora genus.
Cultivated diatoms also enabled the characterization of the phycosphere and isolation of
diatom-associated bacterial strains.

Abstract (croatian)

Glavate želve su drevni morski gmazovi koji nastanjuju svjetska mora i oceane. Njihov
probavni sustav te oklop i koža kolonizirani su mikroorganizmima. U ovoj disertaciji čiji su
rezultati predstavljeni u sklopu četiri znanstvene publikacije, mikrobne zajednice dijatomeja i
bakterija glavatih želvi su analizirane koristeći molekularne metode sekvenciranja visoke
protočnosti kloroplastnog rbcL gena i 16S rRNA gena te kultiviranjem. Rezultati metoda
neovisnih o kultivaciji su pokazali da su bakterijske zajednice u kloaki glavate želve raznolike
ali stabilne te da oralna mikrobiota reflektira okoliš u kojem se kornjača nalazi. Karapaks i koža
podloga su složenim mikrobnim zajednicama u kojima su često prisutni još uvijek nepoznati
mikroorganizmi. Dijatomeje izolirane s karapaksa i kože kultivirane su kao ksenične
monokulture te su korištene morfološke i molekularne metode za njihovu identifikaciju i
određivanje filogenije. Otkrivene su nove svojte dijatomeja unutar rodova Craspedostauros,
Fallacia i Amphora. Kultivacija dijatomeja također je omogućila analizu fikosfere te izolaciju
pripadajućih bakterijskih sojeva.

• Keywords: microbiome; microbial communities; amplicon sequencing; reptiles; phycosphere
• Keywords (croatian): mikrobiom; mikrobne zajednice; amplicon sekvenciranje; gmazovi; fikosfera
• Language: english
• URN:NBN: urn:nbn:hr:217:718540
• Promotion: 2022
• Study programme: Title: Biology; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti, područje prirodnih znanosti, polje biologija (doktor/doktorica znanosti, područje prirodnih znanosti, polje biologija)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access; Embargo expiration date: 2023-09-29
• Created on: 2022-12-06 12:11:36