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Marine Developmental Biology

Master Students, oppurtunities

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Photo:
Ellinor Bartle

MDB may recruit Master students from these programs:
Master's Programme in Aquaculture Biology
Master's Programme in Marine Biology - Fisheries Biology
Master's Programme in Nutrition - Nutrition of Aquatic Organisms in Aquaculture

Masterprogram i biologi - studieretning utviklingsbiologi og fysiologi

 

Students will typically work in a team where the student’s project is part of ongoing activities in the group often as part of projects funded by the Research Council of Norway. However, if the students have specific interests/ideas, it may be possible to design a specific subject of study within a research area. We strongly recommend prospective students to contact potential supervisors to discuss possibilities for thesis subjects. For Master subjects currently available, see below (Prospects for Master subjects)

Examples of previous Master thesis

Snorre Bakke Dietary inclusion of peptides and the effect on the regional expression of the oligo-peptide transporter PepT1 (SLC15A1) in the intestine of Atlantic cod (Gadus morhua).

Summary: Optimizing the growth rate of fish is a major interest to the aquaculture industry . The correct nutrient composition of the feed is essential to minimize the food to growth ratio. The availability of fish meal as a protein ingredient in fish feed is already becoming limited, so the search for alternative sources of protein has been initiated on a broad scale world wide. In order to replace fish meal, which is considered an optimal protein source for carnivorous teleosts, it is very important to have a thorough knowledge about all aspects of protein nutrition including the digestive process, There is very little knowledge about interactions between amino acid/ peptides and protein components in the feed and various intracellular and extracellular molecules and pathways. Peptides are known to have a wide range of physiological effects and the research on bioactive peptides have escalated over the last years. Peptides that are transported over the brush border membrane are normally hydrolysed by cytoplasmatic peptidases and mainly free amino acids are transported out of the basal membrane of the mucosa cells and into the portal circulation. However, small peptides that are resistant to hydrolysis may enter the blood, and this is important for the roles of the bioactive peptides. Peptide transport may therefore be an important route for absorption of both dietary proteins and bioactive peptides in teleost fishes similar to that observed in humans. The project focused on identifying regulatory mechanisms on intestinal peptide absorption induced by intraluminal substrates and how dietary composition will influence expression of the peptide transporter.

Ragnhild Valen Spatial and temporal mRNA expression of key gastrointestinal peptide hormones in Atlantic salmon during processing of a single meal- towards an understanding of their roles in regulation of digestion and appetite.

Summary: The gastrointestinal tract (GI tract) in fish deal with large variations in feed availability, feeding habitats and environmental conditions. A rapid adaption response is vital and is highly dependent on endocrine signalling between the GI tract and the brain. Both regulatory peptides and hormones modulate the GI tract in order to optimize energy input in the form of digestion and absorption, but also the feeding behaviour in fish. When fish are starved or fed, the expression of these peptides and hormones varies according to difference in energy status. The gene expression profile can thus be viewed in terms of the physiological responses such as digestion, absorption and appetite. The overall aim of this master thesis work was to gain increased knowledge of the occurrence, function and distribution of the GI peptide hormones: Ghrelin-1, Ghrelin-2, peptide YY (PYY), Cholecystokinin (CCK) -1 and CCK-2 in Atlantic salmon GI tract. This knowledge is useful in elucidating the basic responses of digestion and appetite in fish. Methods such as; RNA isolation, DNase treatment, cDNA synthesis and real time quantitative PCR (q-PCR) was used in this master thesis work.

Tharmini Kalananthan Tissue distribution profile of sLeptin A1 mRNA in ongrowing Atlantic salmon (Salmo salar L.)-Effects of feeding level.

Summary: Leptin is a peptide hormone that in mammals is mainly produced and secreted into circulation from adipose tissue, largely reflecting body fat reserves. It is also important for regulating food intake, pathophysiology of obesity and is postulated to be implicated in puberty. However information regarding leptin in non-mammalian species is still scarce. Recent research showed that fish species express leptin homologous to mammalian leptin eg, puffer. The thesis characterized the tissue specific expression of leptin mRNA in Atlantic salmon fed two levels of feed (60 and 100% of ad lib). The findings of this project provides basic information regarding factors that underlie regulation of body weight, fat allocation, onset of puberty and early maturation in salmon. These are some of the major challenges in the aquaculture industry today.

Prospects for Master subjects

Currently we have the following Thesis projects available

Topic/ Research areaContact

Molecular regulation of Cell Cycle variants
- Function of modified cyclin and CDK variants in Oikopleura
- Chromatin dynamics in altered cell cycles

Eric Thompson

Climate Change and marine pelagic ecosystems
- Enchanced roles of gelatinous zooplankton in warmer acidified oceans
- Global vertical carbon flux regulation

Eric Thompson

Non-visual photoreception
- Characterization of non-visual photoreceptors
- Development of the non-visual photoreceptor systems

Jon Vidar Helvik

Color vision in fish
- Characterization and topographic organization of photoreceptors in the eye in marine fishes
- Adaptation of the visual systems to marine light environment
- Changes in the visual system during development and life stage transformations

Jon Vidar Helvik

Growth and puberty in fish
- Environmental and endocrine control
- Effects of androgens on endocrine axes
- Osmoregulatory effects of sex steroids
Species:
salmon

Sigurd Stefansson

Smoltification
- Environmental and endocrine control
- Osmoregulatory changes and SW adaptation
- Neuroendocrine changes (w/Lars Ebbesson)
Species:
salmon

Sigurd Stefansson

Digestive physiology of fish larvae
- Endocrine control systems
- Processing capacity
- Ontogeny start feeding to juvenile
Species:
cod (torsk), halibut (kveite)

Ivar Rønnestad

Appetite and Energy homeostasis in fish
- Endocrine control systems (brain)
- Interactions with digestion
- Effects of leptin
Species:
cod (torsk), halibut (kveite), salmon (laks)

Ivar Rønnestad