FATTY-ACIDS OF DUNALIELLA-TERTIOLECTA AND SKELETONEMA-COSTATUM GROWN IN THE PRESENCE OF PHENYLTIN COMPOUNDS

The fatty acid compositions of a marine chlorophyte, Dunaliella tertio lecta Butcher and a marine diatom, Skeletonema costatum (Greville) Cle ve, which exhibit different resistances to phenyltin, were studied. Un der similar growth conditions, the fatty acid profiles of both the chl orophyte and the diatom were similar to those reported by other author s studying the same, or closely related species. Batch cultures of D. tertiolecta grown for 72 h contained a spectrum of fatty acids with ch ain lengths from 12 to 24 carbons, 52% of which were unsaturated and 2 3% of which were polyunsaturated (PUFA's). Major fatty acids in D. ter tiolecta were 16:0, 16:2 and 18:1. Skeletonema costatum grown under si milar conditions contained fatty acids with chain lengths from 14 to 2 4 carbons. Major fatty acids were 14:0, 16:0 and 16:1. Unsaturates mad e up 52% of total fatty acids while 22% of total fatty acids were PUFA 's. In order to test the hypothesis that sensitivity to phenyltins is related to their fatty acid composition, attempts were made to culture D. tertiolecta in the presence of triphenyltin (TPhT) ranging in conc entration from 0.0021 to 0.21 mu M, and S. costatum in the presence of TPhT and diphenyltin (DPhT) in concentrations ranging from 0.000084 t o 0.0084 mu M and 0.0084 to 0.84 mu M respectively. Growth occurred in all cultures except for D. tertiolecta exposed to 0.21 mu M TPhT. Gro wth of S. costatum was inhibited at 0.084 mu M DPhT and higher concent rations. The fatty acid composition of 72 h cultures grown in the pres ence of phenyltins was examined. Exposure of D. tertiolecta to TPhT re sulted in a 45% increase in monounsaturated fatty acids with a concomi tant decrease in total PUFA's. Growth of S. costatum in the presence o f either phenyltin did not alter the proportion of total unsaturates, total monounsaturates or total PUFA's. There was no apparent correlati on between the fatty acid composition of the algae tested and their se nsitivity to phenyltins.