Highly unsaturated fatty acid synthesis in marine fish: cloning, functional characterization, and nutritional regulation of fatty acyl delta 6 desaturase of Atlantic cod (Gadus morhua L.).

This study reports the cloning, functional characterization, tissue expression, and nutritional regulation of a delta6 fatty acyl desaturase of Atlantic cod (Gadus morhua). PCR primers were designed based on the sequences of conserved motifs in available fish desaturases and used to isolate a cDNA fragment from cod liver, with full-length cDNA obtained by rapid amplification of cDNA ends. The cDNA for the putative desaturase was shown to comprise 1980 bp, including a 261-bp 5'-UTR, a 375-bp 3'-UTR, and an ORF of 1344 bp that specified a protein of 447 amino acids.

Cloning and functional characterisation of polyunsaturated fatty acid elongases of marine and freshwater teleost fish.

Enzymes that lengthen the carbon chain of polyunsaturated fatty acids are key to the biosynthesis of the highly unsaturated fatty acids, arachidonic, eicosapentaenoic and docosahexaenoic acids from linoleic and alpha-linolenic acids. A Mortierella alpina cDNA polyunsaturated fatty acid elongase sequence identified mammalian, amphibian, zebrafish and insect expressed sequence tags (ESTs) in GenBank. Consensus primers were designed in conserved motifs and used to isolate full length cDNA from livers of several fish species by Rapid Amplification of cDNA Ends (RACE).

Highly unsaturated fatty acid synthesis in vertebrates: new insights with the cloning and characterization of a delta6 desaturase of Atlantic salmon.

Fish are an important source of the n-3 highly unsaturated fatty acids (HUFA), eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids that are crucial to the health of higher vertebrates. The synthesis of HUFA involves enzyme-mediated desaturation, and a delta5 fatty acyl desaturase cDNA has been cloned from Atlantic salmon (Salmo salar) and functionally characterized previously. Here we report cloning and functional characterization of a delta6 fatty acyl desaturase of Atlantic salmon and describe its genomic structure, tissue expression, and nutritional regulation.

Isolation and physical mapping of sex-linked AFLP markers in nile tilapia (Oreochromis niloticus L.).

Gynogenetically produced XX and YY Nile tilapia (Oreochromis niloticus) and diploid control groups were screened for amplified fragment length polymorphisms (AFLPs) to search for sex-linked or sex-specific markers. Family-level bulked segregant analysis (XX and YY gynogenetic family pools) and individual screening (XX and YY gynogenetics and XX and XY control individuals) identified 3 Y-linked (OniY425, OniY382, OniY227) and one X-linked (OniX420) AFLP markers. OniX420 and OniY425 were shown to be allelic.

Molecular cloning and functional characterization of fatty acyl desaturase and elongase cDNAs involved in the production of eicosapentaenoic and docosahexaenoic acids from alpha-linolenic acid in Atlantic salmon (Salmo salar).

Fish are the only major dietary source for humans of omega-3 highly unsaturated fatty acids (HUFAs) and with declining fisheries farmed fish such as Atlantic salmon (Salmo salar) constitute an increasing proportion of the fish in the human diet. However, the current high use of fish oils, derived from wild capture marine fisheries, in aquaculture feeds is not sustainable in the longer term and will constrain continuing growth of aquaculture activities. Greater understanding of how fish metabolize and biosynthesize HUFA may lead to more sustainable aquaculture diets.

Zebrafish cDNA encoding multifunctional Fatty Acid elongase involved in production of eicosapentaenoic (20:5n-3) and docosahexaenoic (22:6n-3) acids.

Enzymes that increase the chain length of fatty acids are essential for biosynthesis of highly unsaturated fatty acids. The gLELO gene encodes a protein involved in the elongation of polyunsaturated fatty acids in the fungus Mortierella alpina. A search of the GenBank database identified several expressed sequence tag sequences, including one obtained from zebrafish (Danio rerio), with high similarity to gLELO.

Chromosomal regions controlling resistance to gastro-intestinal nematode infections in mice.

Quantitative trait loci (QTL) associated with resistance to an intestinal worm in a well-defined murine model are described. These have been identified in an F(2) population derived from resistant (SWR) and susceptible (CBA) parental mouse strains infected with the gastro-intestinal nematode parasite Heligmosomoides polygyrus. Seven QTL located on six chromosomes are described, associated with components of the complex host response and the differential regulation of parasite survival and reproduction.

Responses of bovine chimaeras combining trypanosomosis resistant and susceptible genotypes to experimental infection with Trypanosoma congolense.

West African N'Dama cattle have developed a genetic capacity to survive, reproduce and remain productive under trypanosomosis risk. The cellular and molecular bases of this so-called trypanotolerance are not known, but the trait is manifested by the N'Dama's greater capacity to control parasitaemia and anaemia development during an infection. In order to examine the role of the haematopoietic system in trypanotolerance, we have exploited the tendency for the placentas of bovine twin embryos to fuse.