Thiafatty acids as tracers to investigate biosynthetic pathways of lepidopteran sex pheromones

In order to investigate the potential utility of thiafatty acids as tracers for biosynthetic studies of moth sex pheromones, a series of thiatetradeca noic acids, namely 8-, 9-, 10-, 11-, 12- and 13-thiatetradecanoic, were pre pared and their metabolism was investigated in pheromone glands of Spodopte ra littoralis. Analysis by gas chromatography coupled to mass spectrometry of extracts from pheromone glands treated with the above acids showed that only 8-thiatetradecanoic acid and 13-thiatetradecanoic acid were metabolize d by desaturation and were incorporated into the sex pheromone biosynthetic pathway. 13-Thiatetradecanoic acid was converted into (E)- and (Z)-13-thia tetradec-11-enoic acids, (Z,E)-13-thiatetradeca-9,11-dienoic acid, 11-thiad odecanoic acid, (E)- and (Z)-11-thiadodec-9-enoic acids and 15-thiahexadeca noic acid. 8-Thiatetradecanoic acid gave rise to two monoenoic thiafatty ac ids and two dienoic thiafatty acids, which were assigned to (Z)- and (E)-8- thiatetradec-11-enoic acids, (Z,E)-8-thiatetradeca-9,11-dienoic acid and (E ,E)-8-thiatetradeca-10,12-dienoic acid. The other thiafatty acids tested, 9 -, 10-, 11- and 12-thiatetradecanoic acids, were not metabolized by desatur ation, although the corresponding products of beta -oxidation and chain elo ngation were detected. The occurrence of sulfoxides was not detected in thi s case, in disagreement with results on the metabolism of some thiaacids pr eviously reported by other authors in yeast, Saccharomyces cerevisiae. (C) 2001 Elsevier Science Ltd. All rights reserved.