MODULATION OF FATTY-ACID INCORPORATION AND DESATURATION BY TRIFLUOPERAZINE IN FUNGI

The effects of trifluoperazine (TFP) on [1-C-14]fatty acid incorporation into the lipids of Mortierella ramanniana var. angulispora were studied. TFP decreased [1-C-14]fatty acid incorporation into phosphatidylcholine, phosphatidylethanolamine and triacylglycerol, but greatly increased C-14-labeling in phosphatidic acid. These changes in [1-C-14]fatty acid incorporation induced by TFP were accompanied by a decrease in desaturation of some [1-C-14]fatty acids taken up by the fungal cells. When [1-C-14]lioleic acid (LA) was incubated with the fungal cells, total gamma-linolenic acid (GLA) formation from incorporated [1-C-14]LA decreased, but the C-14-labeled GLA content in individual lipid classes was essentially unchanged. This suggests that the site of the TFP effect on GLA formation from [1-C-14]LA taken up from the medium is not the desaturase acting on LA linked to complex lipids. On the other hand, GLA formation from [1-C-14]oleic acid was much less susceptible to TFP, which suggests that in this fungus DELTA-6 desaturation to GLA has at least two different pathways with different degrees of susceptibility to TFP.