Development of a qRT-PCR assay to determine the relative mRNA expression of two different trypsins in Atlantic cod (Gadus morhua)

Short-term overcrowding of Atlantic cod, Gadus morhua: effects on serum-mediated antibacterial activity and transcription of glucose transport and antioxidant defense related genes

Serum-mediated control of Listonella anguillarum and transcriptional profiles of selected glucose transport and antioxidant defense genes, following short-term overcrowding in Atlantic cod, Gadus morhua were determined. Fish were subjected to overcrowding by reducing the water level in the tank for 1 h and this was repeated thrice over a 12 h period. Blood samples were collected before overcrowding (initial group) and at 2, 24 and 72 h post-crowding. The sera from fish obtained at 2 h post-crowding caused a significant reduction in L. anguillarum counts compared to the initial samples. There was a transcriptional upregulation of the glucose transport-4 and glyceraldehyde-3-phosphate dehydrogenase genes at 2 h after crowding. Gene transcripts of the antioxidant enzymes, Cu/Zn superoxide dismutase (Cu/Zn SOD), catalase and phospholipid hydroperoxide glutathione peroxidase also significantly increased at 2 h post-crowding, but thereafter they returned to their pre-crowding levels with the exception of Cu/Zn SOD that remained significantly higher than the initial group until 72 h. Thus, short-term overcrowding of Atlantic cod leads to a transient enhancement of in vitro serum antibacterial activity and enhanced transcriptional activity of glucose transport and antioxidant defense genes.

The novel trypsin Y from Atlantic cod (Gadus morhua) - isolation, purification and characterisation

This report describes the isolation and partial characterization of the novel group III trypsin Y from the pyloric caeca of Atlantic cod. Other Atlantic cod trypsins have been used as food processing aids with good results. Trypsin Y was purified by p-aminobenzamidine affinity chromatography and characterized by SDS-PAGE and western blot analysis, as well as by activity measurements towards synthetic substrates. Identification of trypsin Y was done with polyclonal antibodies raised towards the recombinant form of the enzyme and by MALDI-TOF mass spectrometry. Trypsin Y is the only group III trypsin isolated from its native source and characterized by biochemical methods. In accordance with the r-trypsin Y, the native enzyme shows dual substrate specificity, i.e. towards trypsin and chymotrypsin specific substrates. This, along with the high cold-adapted character of trypsin Y, may be valuable for its use as a processing aid for sensitive products such as seafood.

Molecular characterization and gene expression of six trypsinogens in the flatfish Senegalese sole (Solea senegalensis Kaup) during larval development and in tissues

The application of large-scale genomics to Senegalese sole (Solea senegalensis) has allowed for the identification of six different trypsinogen genes. The catalytic triad (His-57, Asp-102, and Ser-195) and other residues required for trypsin functionality were conserved across all trypsinogens. Sequence identities, charges and phylogenetic analysis allowed them to be classified into three groups: group I or anionic trypsinogens (ssetryp1a, ssetryp1b and ssetryp1c), group II or cationic trypsinogen (ssetryp2) and group III or psychrophilic trypsinogens (ssetryp3 and ssetrypY). The expression profiles of these genes were studied in juvenile tissues and during larval development using a real-time PCR approach. In juvenile fish, trypsinogens were expressed mainly in the intestine. Transcripts of ssetryp1c were the highest in all tissues except in brain where those of ssetryp2 were the most abundant. During larval development, ssetryp1 variants and ssetryp2 transcript levels increased from 2 to 6 days after hatching, and decreased thereafter. In contrast, transcripts of group III trypsinogens increased slightly or not significantly in premetamorphosis and decreased at metamorphosis. The expression levels ssetryp3 and ssetrypY were the lowest in larvae (from 172- to 1391-fold lower than ssetryp1 and ssetryp2). In contrast, they were expressed at a similar level as ssetryp2, although lower than ssetryp1, in juvenile tissues.