Atlantic salmon cardiac primary cultures:An in vitro model to study viral host pathogen interactions and pathogenesis

Development of Salmon Cardiac Primary Cultures (SCPCs) from Atlantic salmon pre-hatch embryos and their application as in vitro model for cardiotropic viral infection research are described. Producing SCPCs requires plating of trypsin dissociated embryos with subsequent targeted harvest from 24h up to 3 weeks, of relevant tissues after visual identification. SCPCs are then transferred individually to chambered wells for culture in isolation, with incubation at 15-22°. SCPCs production efficiency was not influenced by embryo's origin (0.75/ farmed or wild embryo), but mildly influenced by embryonic developmental stage (0.3 decline between 380 and 445 accumulated thermal units), and strongly influenced by time of harvest post-plating (0.6 decline if harvested after 72 hours). Beating rate was not significantly influenced by temperature (15-22°) or age (2-4 weeks), but was significantly lower on SCPCs originated from farmed embryos with a disease resistant genotype (F = 5.3, p<0.05). Two distinct morphologies suggestive of an ex vivo embryonic heart and a de novo formation were observed sub-grossly, histologically, ultra-structurally and with confocal microscopy. Both types contained cells consistent with cardiomyocytes, endothelium, and fibroblasts. Ageing of SCPCs in culture was observed with increased auto fluorescence in live imaging, and as myelin figures and cellular degeneration ultra-structurally. The SCPCs model was challenged with cardiotropic viruses and both the viral load and the mx gene expression were measurable along time by qPCR. In summary, SCPCs represent a step forward in salmon cardiac disease research as an in vitro model that partially incorporates the functional complexity of the fish heart

Nanopore sequencing for rapid diagnostics of salmonid RNA viruses

This work received support from the Biotechnology and Biological Sciences Research Council (grant BB/M010996/1) and Marine Scotland Science. The authors thank Dr Elena Fringuelli (Agri-Food and Biosciences Institute, Belfast) for providing some of the SAV material used.Peer reviewedPublisher PD

Identification of a wild reservoir of salmonid alphavirus in common dab Limanda limanda, with emphasis on virus culture and sequencing

Peer reviewedPublisher PD

Transcriptomic responses of European flounder (Platichthys flesus) liver to a brominated flame retardant mixture

Male European flounder (Platichthys flesus) were exposed to a technical mixture of brominated diphenyl ethers (PDBEs, DE-71, Pentamix) that had been purified to remove contaminating dioxins. Controls were exposed to carrier solvent alone. Fish were exposed to decadally increasing concentrations of Pentamix via both sediment and spiked food. The GENIPOL P. flesus cDNA microarray, differentially expressed gene profiling (DEG) and quantitative PCR were employed to detect hepatic transcriptional differences between exposed fish and controls. Gene transcriptional changes were more sensitive to Pentamix exposure than biomarkers measured previously. Pentamix exposure induced transcripts coding for enzymes of xenobiotic metabolism (CYP1A, aldo-keto reductases) and elicited endocrine disruption (vitellogenin and thyroid hormone receptor alpha), with effects on CYP1A and VTG occurring at the highest exposure. Ontology analysis clearly showed dose-responsive changes indicative of oxidative stress, induction of mitochondrial dysfunction, and apoptosis. We conclude that exposure to PBDEs in both sediment and food has a significant adverse effect on a broad range of crucial biochemical processes in the livers of this widely distributed estuarine fish species, the flounder. © 2013 Elsevier B.V

Microhabitat distribution of some monogenoideans, parasitizing the gills of Wallago attu (Bl. and Sch., 1801) and their seasonal variation

The parasitic microhabitat distribution of the monogenoideans Thaparocleidus wallagonoius Jain, 1952, Mizelleus indicus Jain, 1957and T. gomtius Jain, 1957 parasitizing the gills of a fresh-water demersal Wallago attu and their seasonal variations were investigated in the present study. The microhabitat preferences of these species were observed. The gill segments and gill areas were the most important factors segregating the monogenoidean parasites on gills, not their abundance. Low niche overlap was found within each of the four gill arches and parasites were segregated in the same microhabitats within each gill arch. The distribution of parasites was independent of the left or right side of gill. The distribution plots in our study indicated that the anterior segment of first and fourth gill arches were more preferred site of infection. Seasonal variation of parasites, recorded during 2006 & 2007, in male and female hosts was also investigated. Due to ectoparasitic nature and high host specificity exhibited by the species of monogenoidea, studies on their seasonal dynamics are very significant as they could contribute significantly to the understanding of their biological adaptations to their environment