The elongases of Echinogammarus marinus

Gammarids, aquatic invertebrates that are abundant in benthic communities in virtually all aquatic environments, have nutritional profiles characterised by a high protein content, low levels of carbohydrates, and relatively high contents of n-3 long-chain polyunsaturated fatty acids (LC-PUFAs). Such characteristics, along with the possibility to establish high density cultures, have prompted interest for using gammarids in aquaculture. Importantly, previous studies reported on the ability of gammarids to be grown on a variety of sidestreams and, consequently, gammarids arise as promising candidates to apply circular economy principles by which sidestreams can be utilised for the production of biomass with high nutritional value. IMPROMEGA aimed to establish whether marine gammarids are able to convert short-chain fatty acids into the high-value, physiologically essential LC-PUFAs. The results show that gammarids have, at least, three distinct elovl genes with putative roles in LC-PUFA biosynthesis. Phylogenetic analyses allowed to classify two elongases as Elovl4 and Elovl6, and a third one as “Elovl1/7- like” since it grouped closely to vertebrate Elovl1 and Elovl7 sequences. The functions of the gammarid elongases were investigated using the Echinogammarus marinus Elovl sequences. Both the E. marinus Elovl4 and Elovl1/7-like were able to elongate PUFA substrates ranging from C18 to C22. E. marinus Elovl6 is only able to elongate C18 PUFA substrates. Current investigations focus on elucidating the presence of fatty acyl desaturases, enzymes that, like elongases, are required for the biosynthesis of LC-PUFAs in animals.

See Ribes-Navarro et al. (2021), Marine Drugs 19, 226