Blar i tittel Mastergradsoppgaver i biologi
Viser treff 169-188 av 362
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Immunostimulants connecting innate and adaptive immunity in Atlantic salmon (Salmo salar)
(Master thesis; Mastergradsoppgave, 2007-11-15)The use of immunostimulants in fish farming has received increased attention due to the discovery of Toll-like receptors (TLRs) and pattern recognition receptors (PRRs). These receptors have been found to bind to highly conserved motifs on the surface of pathogens, known as pathogen associated molecular patterns. Most of the studied PAMPs activate antigen presenting cells (APCs) together with naïve ... -
Impact of autopolyploidy on leaf structure and photosynthesis in Saxifraga oppositifolia L.
(Master thesis; Mastergradsoppgave, 2023-12-01)Polyploidization can be a rapid path to speciation and is considered an important evolutionary mechanism. Some predict that all plants have undergone a polyploidization event during their evolutionary history, and the frequency of polyploid species increases with latitude. The Arctic-Alpine Saxifraga oppositifolia, an autopolyploid, has two polyploids that have successfully established themselves ... -
The impact of different size herbivores on plant biomass in Yamal (Russia)
(Master thesis; Mastergradsoppgave, 2016-05-19)Tundra ecosystems are changing environments that are greatly affected by plant-herbivore relationships. Many herbivores of different sizes eat, trample or clip plants. However they can also act as support through nutrient addition by faeces. In this study I look at the impact of three sizes of herbivores (large, medium and small) on ten functional groups of plants (nitrogen-fixing forbs, erect ... -
Impacts of water level regulation on trophic niche and growth of Arctic charr (Salvelinus alpinus) and brown trout (Salmo trutta) in Norwegian hydropower reservoirs
(Master thesis; Mastergradsoppgave, 2019-05-15)Hydropower is among the largest renewable energy sources globally. However, it can have drastic environmental and socio-economic impacts on dammed lakes (i.e., reservoirs) and rivers where water levels are regulated due to hydropower operations. Water level regulation in hydropower reservoirs is known to be a large environmental problem, leading to changes in the abiotic conditions, which subsequently ... -
The Importance of Morphological/Physiological Heterogeneity as Adaptive Strategies in Stocks of Common Northern/Arctic Phytoplankton Species with Special Focus on the Common Diatom Chaetoceros socialis
(Master thesis; Mastergradsoppgave, 2006-12-13)The cosmopolitan, centric diatom Chaetoceros socialis was investigated in terms of its validity as a single species characterized by its morphology, physiology and distribution. A database was constructed using my own and published literature distribution observations of C. socialis in Northern Norway, the Atlantic, Arctic and Barents Sea. From this range of observations, it is possible to establish ... -
In Silico Screening for inhibitors against Apicoplast Phosphate Translocator from Toxoplama gondii
(Master thesis; Mastergradsoppgave, 2019-05-16)Apicomplexa parasites, including Toxoplasma gondii and Plasmodium falciparum, contain a secondary endosymbiosis-derived plastid like organ, called apicoplast, which is an anabolic hub. This apicoplast is fueled by phosphate translocator (APT), which transport phosphorylated sugar molecules in exchange of inorganic phosphate. Disruption of APT in T. gondii was found to be lethal for parasite. Beside ... -
Infectious agents involved in infectious keratoconjunctivitis in semi-domesticated reindeer (Rangifer tarandus tarandus) in Fennoscandia.
(Master thesis; Mastergradsoppgave, 2015-11-12)Infectious keratoconjunctivitis (IKC) is one of the most common ocular diseases in ruminants worldwide. Animals affected by this disease can show a wide variety of clinical symptoms, including keratitis, uveitis, corneal ulcer, conjunctivitis and in severe cases, blindness. Moraxella spp., Chlamydia spp. and Mycoplasma conjunctivae have been described as primary causative agents in ruminant species ... -
Inflammatory responses in lumpfish (Cyclopterus lumpus L.) vaccinated at different water temperatures with intraperitoneal injection
(Master thesis; Mastergradsoppgave, 2021-05-18)The use of lumpfish (Cyclopterus lumpus L.) as cleaner fish in salmonid aquaculture for the biological control of sea lice infestation levels has increased in recent years. The species is relatively new to aquaculture and susceptible to various infectious agents. The health situation for lumpfish is currently considered poor, indicating the necessity for developing more efficient vaccines. Studying ... -
The influence of herring (Clupea harengus) biomass and distribution on killer whale (Orcinus orca) movements on the Norwegian shelf
(Master thesis; Mastergradsoppgave, 2020-06-01)Killer whales (Orcinus orca) have a cosmopolitan distribution with a broad diet ranging from fish to marine mammals. Regional populations show local prey specialization and their movements are tightly linked to those of their prey. Norwegian killer whales are known to feed extensively on Norwegian spring spawning (NSS) herring (Clupea harengus). Over the last decade, killer whales have begun to ... -
Influence of photoperiod on central appetite regulation in captive Svalbard rock ptarmigan (Lagopus muta hyperborea)
(Master thesis; Mastergradsoppgave, 2018-08-09)The Svalbard rock ptarmigan displays a seasonal change of body mass as a selectively beneficial adaptation for survival in the high Arctic. This physiological change is sensitive to photoperiod (daylight duration in a 24h cycle) but little is known of the mechanism through which changes in photoperiod affects body mass in this species. We exposed winer adapted Sv. rock ptarmigan to a simulated ... -
Ingestion and egestion of microplastic fibers in the green sea urchin Strongylocentrotus droebachiensis: An experimental exposure
(Master thesis; Mastergradsoppgave, 2021-05-18)Plastic is a major component of marine litter in the world’s oceans and therefore it is critical we develop a better understanding of the fate of plastic in the marine environment, and the potential impacts on biota. Microplastics are the most abundant size class (<5 mm) of plastic found in the marine environment and have the potential to interact with smaller marine organisms at lower trophic levels. ... -
Ingestion of Tyre Crumb Rubber and Uptake of Associated Contaminants in Marine Invertebrates (Pandalus borealis) and Fish (Cyclopterus lumpus) – An Experimental Exposure Study
(Master thesis; Mastergradsoppgave, 2022-05-15)Crumb rubber (CR) produced from end of life vehicle tires is widely used on artificial sports fields and to create urban artificial surfaces. It is also used as a surrogate for tyre wear particles in experimental studies simulating the behaviour and effects of car tyre particles in the environment. It is known to contain a wide range of organic chemicals and metals, some of which are only just being ... -
Initial Community Convergence on Plant Defense Syndromes Explains Community Responses to Herbivore Exclosures
(Master thesis; Mastergradsoppgave, 2017-11-15)General trade-offs in species’ energy use are highlighted here by mapping proposed defense syndromes, using trade-offs found between: constitutive phenolic compounds, silica and a high nutrient low defense region found between regional con-specifics. Differences in species composition between two catchments can be explained by proposed syndrome trade-offs seeking energy use optimums in differing ... -
Initielle studier av Mll3104 og Mll3105 fra Mesorhizobium loti : proteiner antatt involvert i katabolisme av trehalose
(Master thesis; Mastergradsoppgave, 2007-12)Rhizobiacea utgjør en bakterieslekt der de fleste medlemmene er i stand til å inngå symbioser med diverse legumer. Slekten innbefatter Rhizobium, Sinorhizobium, Mesorhizobium, Bradyrhizobium og Azorhizobium, og kollektivt omtales disse for rhizobia. Partnerskapet med legumer er av mutualistisk karakter, der mikrosymbionten bidrar med fiksert nitrogen i form av NH3, og planteverten sørger for en ... -
Interactions between white-tailed eagle Haliaeetus albicilla, seabirds and tourism; how the breeding success of the endangered black-legged kittiwake Rissa tridactyla is affected
(Master thesis; Mastergradsoppgave, 2021-12-17)In many seabird colonies along the coast of Norway, the increased population of white-tailed eagle Haliaeetus albicilla and the growing industry of birdwatching tourism are causing a dilemma for management decisions. Thus, this study aimed to examine the indirect effect of white-tailed eagles and tourists on the breeding success of the endangered seabird species, black legged kittiwake Rissa tridactyla ... -
An interannual study of foraging behaviour in sympatrically breeding macaroni Eudyptes chrysolophus and chinstrap penguins Pygoscelis antarcticus at Bouvetøya
(Master thesis; Mastergradsoppgave, 2019-08-15)Species are likely to segregate their ecological niches to minimize competition for resources, but for centrally foraging predators that breed on sub-Antarctic islands in the Southern Ocean the possibility of niche segregation may be minimal. This study is the first to examine the spatial and trophic aspects of the foraging niche of sympatrically breeding macaroni and chinstrap penguins at the ... -
Interannual variability (2014-2019) of hydrography, fluorescence and nutrient distribution in Vestfjorden, Lofoten
(Master thesis; Mastergradsoppgave, 2020-06-01)Vestfjorden is an area of great ecological relevance since it is one of the main spawning areas of North East Atlantic cod. The survival rate of the cod larvae depends greatly on the abundance of zooplankton, which in turn depends on phytoplankton. Due to the extreme seasonality of high latitude fjords with a short productive season, understanding the phytoplankton distribution in spring is crucial. ... -
Investigating population genomic structure of salmon lice (Lepeophtheirus salmonis) in northern Norway
(Master thesis; Mastergradsoppgave, 2019-05-14)Salmon louse (Lepeophtheirus salmonis) is a parasitic copepod that causes significant damage to Atlantic salmon (Salmo salar) and incurs significant costs to the salmonid aquaculture industry. In Norway, the industry has been coping with salmon lice issues with various methods such as chemical treatments, but it has resulted in an acquisition of resistance in salmon lice towards the existing delousing ... -
Isolation and Characterization of Bacteriophages from the Arctic
(Master thesis; Mastergradsoppgave, 2023-05-14)Bacteriophages are viruses that specifically infect bacteria. These obligate intracellular parasites are Earth's most copious, ubiquitous, and genetically diverse (unexplored) biological entities. Organisms in the Arctic environment constantly experience extreme conditions, therefore life in the Arctic evolved different specialized strategies and molecules to survive which offers huge opportunities ... -
Isolation of Fungal Endophytes from Grasses by Laser Micro Dissection & Pressure Catapulting
(Master thesis; Mastergradsoppgave, 2013-12-12)A very diverse group of fungi capable of forming endophytic associations may have profound consequences for natural ecosystems as well as for cultivated plants. Fungal endophytes may benefit their host plants by producing secondary metabolites, and may be an important source for bioactive antimicrobial compounds, used in agriculture, commercial industry, and in medicine. Earlier studies on endophytes ...