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Deletion of the s2m RNA Structure in the Avian Coronavirus Infectious Bronchitis Virus and Human Astrovirus Results in Sequence Insertions
Get PDFCoronaviruses infect a wide variety of host species, resulting in a range of diseases in both humans and animals. The coronavirus genome consists of a large positive-sense single-stranded molecule of RNA containing many RNA structures. One structure, denoted s2m and consisting of 41 nucleotides, is located within the 3′ untranslated region (3′ UTR) and is shared between some coronavirus species, including infectious bronchitis virus (IBV), severe acute respiratory syndrome coronavirus (SARS-CoV), and SARS-CoV-2, as well as other pathogens, including human astrovirus. Using a reverse genetic system to generate recombinant viruses, we investigated the requirement of the s2m structure in the replication of IBV, a globally distributed economically important Gammacoronavirus that infects poultry causing respiratory disease. Deletion of three nucleotides predicted to destabilize the canonical structure of the s2m or the deletion of the nucleotides corresponding to s2m impacted viral replication in vitro. In vitro passaging of the recombinant IBV with the s2m sequence deleted resulted in a 36-nucleotide insertion in place of the deletion, which was identified to be composed of a duplication of flanking sequences. A similar result was observed following serial passage of human astrovirus with a deleted s2m sequence. RNA modeling indicated that deletion of the nucleotides corresponding to the s2m impacted other RNA structures present in the IBV 3′ UTR. Our results indicated for both IBV and human astrovirus a preference for nucleotide occupation in the genome location corresponding to the s2m, which is independent of the specific s2m sequence.publishedVersio
Effects of dietary lipid level and environmental temperature on lipid metabolism in the intestine and liver, and choline requirement in Atlantic salmon (Salmo salar L) parr
Get PDFCholine was recently established as an essential nutrient for Atlantic salmon at all life stages. Choline deficiency is manifested as an excessive accumulation of dietary fat within the intestinal enterocytes, a condition known as steatosis. Most of today's plant-based salmon feeds will be choline-deficient unless choline is supplemented. Choline's role in lipid transport suggests that choline requirement may depend on factors such as dietary lipid level and environmental temperature. The present study was therefore conducted to investigate whether lipid level and water temperature can affect steatosis symptoms, and thereby choline requirement in Atlantic salmon. Four choline-deficient plant-based diets were formulated differing in lipid level of 16, 20, 25 and 28 % and fed to salmon of 25 g initial weight in duplicate tanks per diet at two different environmental temperatures: 8 and 15 °C. After 8 weeks of feeding, samples of blood, tissue and gut content from six fish per tank were collected, for analyses of histomorphological, biochemical and molecular biomarkers of steatosis and choline requirement. Increasing lipid level did not affect growth rate but increased relative weight and lipid content of the pyloric caeca and histological symptoms of intestinal steatosis and decreased fish yield. Elevation of the water temperature from 8 to 15 °C, increased growth rate, relative weight of the pyloric caeca, and the histological symptoms of steatosis seemed to become more severe. We conclude that dietary lipid level, as well as environmental temperature, affect choline requirement to a magnitude of importance for fish biology and health, and for fish yield.publishedVersio
Reduksjon av smeltevann fra fisketransport
Get PDFUndersøkelser i prosjektet viser at det er store forskjeller mellom de ulike aktørene i bransjen med tanke på temperaturkontroll av fisk. Hovedutfordringen med avrenning ligger nok hos produsentene, der fisken generelt ikke blir tilfredsstillende nedkjølt. De aller fleste som deltok i studien har et temperaturmål på 1-3 °C for fisk som pakkes med is, noe som vil gi smelting av is og avrenning under lagring og transport. Det finnes flere tilgjengelige metoder for å samle opp smeltevann som produseres. Tette kasser fremstår som et alternativ som raskt kan implementeres hvis fisken er tilstrekkelig nedkjølt. Et annet alternativ er å montere oppsamlingstanker på lastebilene. Det var til dels store forskjeller hvilket fokus avrenning hadde i Irland, Island og Færøyene. Færøyene hadde det beste systemet med organisert oppsamling og mottak av avrenningsvann. Den matematiske modellen som ble utviklet, bekrefter at temperaturen på fisken har størst innvirkning på avrenningen, men at lastebilen også må gjøre sin del av jobben. Det anbefales at fisken er kaldere enn 1 °C, og at lastebilen stilles inn på -1 til 0 °C.Reduksjon av smeltevann fra fisketransportpublishedVersio
Investigating paired comparisons after principal component analysis
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Design-led innovation for more plant-based food: An interdisciplinary approach to more consumer-centric product development
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Current and Expected Trends for the Marine Chitin/Chitosan and Collagen Value Chains
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Diverse Transcriptome Responses to Salinity Change in Atlantic Cod Subpopulations
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Effects of dietary lipid level on growth, digestive physiology and disease resistance in lumpfish (Cyclopterus lumpus)
Get PDFLumpfish (Cyclopterus lumpus) aquaculture has expanded greatly in recent years due to demands for sea lice cleanerfish from the salmon industry. There are knowledge gaps in lumpfish digestive physiology, nutrient requirement and implications of nutrition for health and disease susceptibility. The present study, conducted to follow up our recent screening trials for estimation of optimal balance of protein, lipid and carbohydrate in diets for lumpfish, involved challenging the fish with Aeromonas salmonicida after a feeding period with diets varying in lipid composition. Three experimental diets were formulated to have similar content of digestible protein and carbohydrate but varying in content of lipid from 6.7 to 18%. Lumpfish with average body weight at start of 1.7 ± 0.03 g were fed the experimental diets in triplicate tanks each (110 fish per tank, in total 990 fish in 9 tanks) for a period of 90 days. After termination of the feeding trial and subsequent collection of biological samples, remaining fish were challenged with atypical A. salmonicida. No significant effects of diet were observed for growth performance. Carcass composition showed increasing content of lipid, protein, and energy with increasing dietary lipid level. Increasing dietary lipid also increased hepatic dry matter, lipid and energy levels, while crude protein decreased. Blood plasma nutrient levels and biomarkers of liver function showed few significant effects of diet, but dietary lipid level increased plasma cholesterol. Intestinal trypsin activity increased with increasing dietary lipid, whereas activity of other digestive enzymes and digesta bile salt levels were unaffected by diet. Increasing lipid level also increased lipid accumulation in the proximal and mid intestine. Expression profiling of genes related to digestive and immune function showed few effects of diet, but the nutrient transporters fabp2 and slc15a1, as well as the immune genes MHCII, igm, and nfkb showed increases with dietary lipid levels, whereas the cholesterol transporter npc1l1 was suppressed. Diet composition did not affect the lumpfish’ resistance against A. salmonicida. To conclude, the variation in macronutrient composition induced modulations in metabolic, digestive and some immune functions. Modulations seemed however to be within normal ranges and did not produce clear compromises in immune responses to bacterial infection.Effects of dietary lipid level on growth, digestive physiology and disease resistance in lumpfish (Cyclopterus lumpus)publishedVersio
