Polychaetes

Polychaetes

Polychaetes are major components of benthic fauna and thus play important roles to maintain a robust food web as a recycler of organic matter and a prey item for higher trophic level species. We have investigated the ωx desaturases, enzymes enabling endogenous production of ω3 long-chain polyunsaturated fatty acids (LC-PUFA), from the common ragworm, Hediste diversicolor, a common inhabitant in sedimentary littoral ecosystems of the North Atlantic. Our functional analysis reveals that the H. diversicolor ωx desaturases have unique desaturation capacities. An ω3 desaturase mediates the conversion of ω6 fatty acid substrates into their corresponding ω3 products including docosahexaenoic acid (22:6ω3, DHA). A further ωx desaturase from H. diversicolor shows unique regioselectivities combining both ω6 and ω3 desaturase activities. These results illustrate that nereid polychaetes have high capacity for LC-PUFA biosynthesis.