A hot area of lipid research today is focused on n-3 polyunsaturated fatty acids, better known by the abbreviation PUFAs. They have been shown to have positive anti-inflammatory effects on blood and the heart and are being considered in the development of medication and nutritional supplements. The PUFA eicosapentaenoic acid, or EPA, is already used to treat hyperlipidemia and arteriosclerosis; another PUFA, docosahexanoid acid, or DHA, is known to have an important role in eye and brain development and has been suggested to be linked to normal brain function.
Fish oils are now the major commercial sources of these two PUFAs; it is expected that the increasing global demand for these PUFAs will exceed the amount currently available through these traditional sources. To keep up with this increased demand, microorganisms and plants are being looked to as possible alternative sources. Thraustrochytrids, filament-producing marine microorganisms, are known to produce and store high amounts of PUFAs in lipid droplets, so the pathways they use to generate them are being investigated as part of the search for an alternative source of PUFAs.
In a Journal of Lipid Research paper entitled “The analysis of Δ12-fatty acid desaturase function revealed that two distinct pathways are active for the synthesis of polyunsaturated fatty acids in Thraustochytrium aureum ATCC 34304” (doi: 10.1194/jlr.M024935), Takanori Matsuda of Kyushu University in Japan and research colleagues studied and identified two active and distinct PUFA-synthesizing pathways in this one species of thraustrochytrid. By disrupting the gene that codes for a Δ12-fatty acid desaturase, a key enzyme in the production of PUFAs, Matsuda et al. were able to show that a desaturase/elongase pathway (also known as the standard pathway) is active in this species. The loss of this Δ12-fatty acid desaturase decreased the number of all types of lipids produced; however, normal cell growth was not affected when the enzyme was not working. Interestingly, their results also suggested DHA is primarily produced by a different PUFA synthase pathway. Their findings suggest genetic modification of these microorganisms for direct production of beneficial PUFAs by one or both of these identified pathways may be possible in the future.
Mary L. Chang (email@example.com) is managing editor of the Journal of Lipid Research and coordinating journal manager of the journal Molecular & Cellular Proteomics.