101 research outputs found

    Influence of essential fatty acid deprivation on thrombocyte aggregation in rainbow trout

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    Indicações sobre alterações na formação das células sanguíneas e em suas funções nos peixes têm sido relatadas em diversos trabalhos. Os ácidos graxos essenciais (EFA) certamente estão ligados a essas células devido ao fato de constituírem fonte de componentes importantes, como os eicosanoides, fatores de ativação de plaquetas nos mamíferos, bem como de fosfolipídios de membrana. Trombócitos oriundos de peixes alimentados com uma dieta comercial contendo quantidades adequadas de EFA mostraram uma grande capacidade de agregação quando induzidos por colágeno do tipo I (56%), contudo, essa capacidade encontrou-se reduzida quando os peixes foram alimentados com uma dieta deficiente em EFA (37%). Os resultados obtidos nesse estudo demonstraram que os ácidos graxos essenciais exercem influência nos trombócitos afetando sua capacidade de agregação.Many reports have indicated that differences in blood cells formation and function in fish could be of dietary origin. Essential fatty acids are certainly connected with these cells by virtue of being a source of important compounds like eicosanoids, platelet activating factor in mammals, as well as the cell membrane phospholipids. The thrombocytes from fish fed the commercial diet containing adequate amount of essential fatty acids exhibited greater capacity for aggregation when induced by Collagen Type I (56%), however, this capacity was reduced when fish were fed the essential fatty acids deficient diet (37%). The results obtained in this study demonstrated that EFA exert influence in thrombocytes by affecting their aggregation capacity

    Diversification of the expanded teleost-specific toll-like receptor family in Atlantic cod, Gadus morhua.

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    BACKGROUND: Toll-like receptors (Tlrs) are major molecular pattern recognition receptors of the innate immune system. Atlantic cod (Gadus morhua) is the first vertebrate known to have lost most of the mammalian Tlr orthologues, particularly all bacterial recognising and other cell surface Tlrs. On the other hand, its genome encodes a unique repertoire of teleost-specific Tlrs. The aim of this study was to investigate if these duplicate Tlrs have been retained through adaptive evolution to compensate for the lack of other cell surface Tlrs in the cod genome. RESULTS: In this study, one tlr21, 12 tlr22 and two tlr23 genes representing the teleost-specific Tlr family have been cloned and characterised in cod. Phylogenetic analysis grouped all tlr22 genes under a single clade, indicating that the multiple cod paralogues have arisen through lineage-specific duplications. All tlrs examined were transcribed in immune-related tissues as well as in stomach, gut and gonads of adult cod and were differentially expressed during early development. These tlrs were also differentially regulated following immune challenge by immersion with Vibrio anguillarum, indicating their role in the immune response. An increase in water temperature from 4 to 12°C was associated with a 5.5-fold down-regulation of tlr22d transcript levels in spleen. Maximum likelihood analysis with different evolution models revealed that tlr22 genes are under positive selection. A total of 24 codons were found to be positively selected, of which 19 are in the ligand binding region of ectodomain. CONCLUSION: Positive selection pressure coupled with experimental evidence of differential expression strongly support the hypothesis that teleost-specific tlr paralogues in cod are undergoing neofunctionalisation and can recognise bacterial pathogen-associated molecular patterns to compensate for the lack of other cell surface Tlrs

    Temperature-dependent lipid accumulation in the polar marine microalga chlamydomonas malina RCC2488

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    The exploration of cold-adapted microalgae offers a wide range of biotechnological applications that can be used for human, animal, and environmental benefits in colder climates. Previously, when the polar marine microalga Chlamydomonas malina RCC2488 was cultivated under both nitrogen replete and depleted conditions at 8°C, it accumulated lipids and carbohydrates (up to 32 and 49%, respectively), while protein synthesis decreased (up to 15%). We hypothesized that the cultivation temperature had a more significant impact on lipid accumulation than the nitrogen availability in C. malina. Lipid accumulation was tested at three different temperatures, 4, 8, and 15°C, under nitrogen replete and depleted conditions. At 4°C under the nitrogen replete condition C. malina had the maximal biomass productivity (701.6 mg L-1 day-1). At this condition, protein content was higher than lipids and carbohydrates. The lipid fraction was mainly composed of polyunsaturated fatty acids (PUFA) in the polar lipid portion, achieving the highest PUFA productivity (122.5 mg L-1 day-1). At this temperature, under nitrogen deficiency, the accumulation of carbohydrates and neutral lipids was stimulated. At 8 and 15°C, under both nitrogen replete and depleted conditions, the lipid and carbohydrate content were higher than at 4°C, and the nitrogen stress condition did not affect the algal biochemical composition. These results suggest that C. malina is a polar marine microalga with a favorable growth temperature at 4°C and is stressed at temperatures ≥8°C, which directs the metabolism to the synthesis of lipids and carbohydrates. Nevertheless, C. malina RCC2488 is a microalga suitable for PUFA production at low temperatures with biomass productivities comparable with mesophilic strains.267872/E50info:eu-repo/semantics/publishedVersio

    A microbial feed additive abates intestinal inflammation in Atlantic salmon

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    The efficacy of a microbial feed additive (Bactocell®) in countering intestinal inflammation in Atlantic salmon was examined in this study. Fish were fed either the additive-coated feed (probiotic) or feed without it (control). After an initial 3-week feeding, an inflammatory condition was induced by anally intubating all the fish with oxazolone. The fish were offered the feeds for 3 more weeks. Distal intestine from the groups was obtained at 4, 24 h, and 3 weeks, after oxazolone treatment.Inflammatory responses were prominent in both groups at 24 h, documented by changes in intestinal micromorphology, expression of inflammation-related genes and intestinal proteome. The control group was characterized by oedema, widening of intestinal villi and lamina propria, infiltration of granulocytes and lymphocytes, and higher expression of genes related to inflammatory responses, mul1b, il1b, tnfa, ifng, compared to the probiotic group or other time points of the control group. Further, the protein expression in the probiotic group at 24 h after inducing inflammation revealed 5 differentially regulated proteins - Calr, Psma5, Trp1, Ctsb and Naga. At 3 weeks after intubation, the inflammatory responses subsided in the probiotic group. The findings provide evidence that the microbial additive contributes to intestinal homeostasis in Atlantic salmon