Project description:Moritella viscosa is a bacterial pathogen causing winter-ulcer disease in Atlantic salmon. The lesions on affected fish lead to increased mortality, decreased fish welfare, and inferior meat quality in farmed salmon. MicroRNAs (miRNAs) are small non-coding RNAs involved in post-transcriptional regulation by guiding the miRNA induced silencing complex to specific mRNA transcripts (target genes). The goal of this study was to identify miRNAs responding to Moritella viscosa in salmon by investigating miRNA expression in head-kidney and the muscle/skin from lesion sites caused by the pathogen. Protein coding gene expression was investigated by microarray analysis in the same materials.
Project description:Bacterial pathogen Moritella viscosa, the causative agent of winter ulcer, causes heavy losses in Atlantic salmon aquaculture. The study compared responses in salmon reared under normal condition (G100) and fish exposed to hypoxia - 60% saturation of dissolved oxygen - at early life (G60). G60 showed lower survival after challenge. Analyses were performed in the most affected tissues: skin and spleen
Project description:Aliivibrio wodanis and Moritella viscosa have often been isolated together from fish with winter ulcer. Little is known about the interaction between the two bacterial species and how the presence of one bacterial species affects the behaviour of the other. The impact on bacterial growth in co-culture was investigated in vitro, and the presence of A. wodanis has a strong inhibitorial effect on M. viscosa. Further, we have sequenced the complete genomes of these two marine Gram-negative species, and have performed transcriptome analysis of the bacterial gene expression levels from in vivo samples. Using bacterial implants in the fish abdomen, we demonstrate that the presence of A. wodanis is altering the gene expression levels of M. viscosa compared to when the bacteria are implanted separately. The impeding effect on growth and the change in the global gene expression pattern of M. viscosa when the two pathogens co-exists is discussed in this paper.
Project description:Salmon alphavirus (SAV) and Moritella viscosa causing respectively pancreatic disease and winter ulcer are among the most important pathogens threatening Atlantic salmon aquaculture. Fish is protected by vaccination with different rate of success. Here, responses to vaccination were assessed followed with pathogen challenges of vaccinated salmon and saline injected control.
