Time filter

Source Type

Hermosillo, Mexico

Bonami J.R.,Montpellier University | Vargas-Albores F.,Marine Biotechnology
Aquaculture Research | Year: 2010

The yellow head virus (YHV) has been reported to be one of most pathogenic viruses for cultivated shrimp; however, serious problems have only been reported in farms in south and southeastern Asian. Recently, a YHV strain was detected in Litopenaeus vannamei cultivated in Mexican farms that lacked virus-associated mortalities or epizooties, and the animals were apparently healthy. The identity of the virus was confirmed by sequencing replicative and structural protein-encoding regions and comparing with homologous virus sequences. Phylogenic relationships and genetic distances were also determined and, although some differences were observed, an influence on virulence was uncertain. In addition, the expression levels of several transcripts (3CLPRO, POL, GP64 and GP116) were evaluated by quantitative real-time polymerase chain reaction during an experimental infection. Although the transcript showed varying kinetics, viral genes were expressed in infected L. vannamei, demonstrating the replicative capability of this YHV strain. © 2009 The Authors. Aquaculture Research © 2009 Blackwell Publishing Ltd. Source

News Article
Site: http://phys.org/biology-news/

For the first time in fish, the team scientifically demonstrated that exposure to stress resulted in 'emotional fever' – where fish temporarily increased their body temperatures by up to four degrees Celsius by moving through a thermal gradient. Dr Sonia Rey, Research Fellow at the University of Stirling's Institute of Aquaculture said: "Our study reopens the discussion upon sentience in fish, which is fundamental to our knowledge of the species and their welfare. This will have a bearing on the development of future regulations and mitigation measures around fish. "With fish brains lacking a cerebral cortex, unlike mammals, birds and reptiles, it has been claimed to date that they have no consciousness. This research removes one of the key arguments underpinning that claim." The research, which focussed on zebrafish, also involved the Universitat Autònoma de Barcelona and the University of Bristol. It features in the journal Proceedings of the Royal Society B. Dr Rey said: "Fish cannot internally regulate their own body temperature. Rather, it equates to the temperature of the environment they are in, and so fish travel between different waters to attain their optimal temperature. "In our study we allowed the fish to choose their own temperature by providing them with a thermal gradient in which they could freely move between interconnected chambers holding water at varying degrees Celsius. "Groups of fish that had been gently submerged in a net for a short period chose to travel, when they were released back into the same temperature chamber, to warmer waters, where they then stayed for several hours. "This 'emotional fever' was the effect of their short confinement. Further studies are now needed to explore the underlying mechanisms of this stress-induced hyperthermia, and to test it against different stressors." Dr Simon MacKenzie, Reader in Marine Biotechnology at the Institute of Aquaculture, said: "Our study has significant impact upon our understanding of how fish use thermal choice to optimise their response to stress. This game changing observation will have far reaching implications in how we approach research in fish and how we consider their welfare." Explore further: Fish go deep to beat the heat

Myrnes B.,Marine Biotechnology | Seppola M.,Marine Biotechnology | Johansen A.,Marine Biotechnology | Overbo K.,Marine Biotechnology | And 4 more authors.
Developmental and Comparative Immunology | Year: 2013

Lysozymes represent important innate immune components against bacteria. In this study, Atlantic salmon (Salmo salar) goose (g-) and chicken (c-) types of lysozyme were subjected to protein characterisations and tissue expression analyses. Specific bacterial protein inhibitors of g- and c-type lysozymes were employed to discriminate between respective enzyme activities. Blood, gills and liver contained activities exclusive for the g-type lysozyme. Only haematopoietic organs (head kidney and spleen) contained enzyme activities of both g- and c-lysozyme enzymes and c-type activity was not found outside these organs. Gene transcript levels proportional to enzyme activity levels were detected for the g-type lysozyme but not for the c-type. In vitro studies revealed significant induction of c-type gene expression and enzyme activity in macrophages after incubation with lipopolysaccharide (LPS) while expression of the g-type lysozyme gene was unaffected. The activity of purified native c-type enzyme was profoundly reduced by divalent cations and displayed low tolerance to monovalent cations, while the native g-type lysozyme was stimulated by monovalent cations and tolerated low concentrations of divalent cations. Activities of both enzymes increased with temperature elevations up to 60 °C. The native g-type lysozyme responses to temperature in particular are in apparent conflict to the ones for the recombinant salmon g-lysozyme.Our results imply separate expression regulations and different functions of c- and g-type lysozymes in salmon. LPS-induced expression of c-type lysozyme and broad constitutive tissue distribution of g-type lysozyme in salmon is different from findings in other studied fish species. © 2013 Elsevier Ltd. Source

Discover hidden collaborations