PhD trial lecture and public defence: Prabhugouda Siriyappagouder (FBA)

21 September 2018 10:15 - 21 September 2018 15:30

Auditorium Elias Blix (A13)

PhD candidate Prabhugouda Siriyappagouder will hold a trial lecture and defend his thesis for the degree Philosophiae Doctor (PhD), at the Faculty of Biosciences and Aquaculture, Nord University.

PhD-candidate: Prabhugouda Siriyappagouder

Title of thesis:
The intestinal mycobiota of zebrafish - community profiling and exploration of the impact of yeast exposure early in life

Title of trial lecture:
Microbial communities in fish, from composition to functionality

Time of trial lecture: 10:15 - 11:15
Time of defence: 12:15 - 15:30
Place: Auditorium Elias Blix (A13)

Members of the evaluation committee:

- Prof. Dr. ir Peter Bossier - Director Laboratory of Aquaculture and Artemia Reference Center, Gent, Belgium
- Researcher Dr. Trond M. Kortner - Department of Basic Sciences and Aquatic Medicine, Faculty of Veterinary Medicine, NMBU, Oslo
- Professor Pål A. Olsvik, FBA, Nord University (leader)


- Main supervisor: Professor Jorge Fernandes, FBA
- Co-supervisor: Professor Kiron Viswanath, FBA

The PhD trial lecture and defence are open to the public. the thesis is available on request. Please contact Kristine Vevik, email:, phone 75 51 74 37

About the thesis:
Fungi (including yeasts) are considered essential components of the gastrointestinal tract of vertebrates and have an important impact on the host health. Compared to bacteria, little is known about fungal communities (mycobiota) and their contribution to the microbial ecosystem in teleosts. 

This thesis represents the first comprehensive characterization of gastrointestinal fungal communities in a model teleost (zebrafish). Further, we examined the ability of fish-associated yeast from zebrafish and Atlantic salmon to modulate the intestinal bacterial communities and transcriptomic response in zebrafish larvae, which were raised under conventional or germ-free conditions. 

Yeasts dramatically altered the microbial composition in the gastrointestinal tract, favoring the growth of beneficial bacteria. Additionally, yeast exposure resulted in up-regulation of genes involved in host metabolism and immunity. 

Altogether, our results underscore the importance of the yeast within the fish microbiota and set a foundation to designing novel strategies to manipulate the host bacterial community, which could contribute to the sustainable development of the aquaculture industry.

Link for streaming: