De novo biosynthesis of linoleic acid and its conversion to the hydrocarbon (Z,Z)-6,9-heptadecadiene in the astigmatid mite, Carpoglyphus lactis: Incorporation experiments with 13C-labeled glucose

De novo biosynthesis of linoleic acid (LA) and its conversion to (Z,Z)-6,9-heptadecadiene were examined in Carpoglyphus lactis (Acarina, Carpoglyphidae). Experiments involving 13C-administration using [1-13C]-d-glucose revealed that 13C atoms were incorporated into LA of total lipid extracted from the mite, resulting in labeling of all even-numbered carbons. This result demonstrated that LA was produced from 13C-labeled acetyl-CoA, which is indicative of direct de novo biosynthesis. In these feeding experiments involving [1-13C]-d-glucose, 13C atoms were also incorporated into (Z,Z)-6,9-heptadecadiene, which is one of the major secretory components in the mite. The labeling pattern of (Z,Z)-6,9-heptadecadiene at odd-numbered carbons agreed well with that of LA after loss of the carboxyl carbon. It was concluded that the mites could stably convert LA into (Z,Z)-6,9-heptadecadiene without the dietary requirement of this essential fatty acid. [Display omitted] •Mites were fed on [1-13C]-d-glucose-enriched diet for the feeding experiment.•13C Atoms of labeled glucose were incorporated into LA and (Z,Z)-6,9-heptadecadiene.•The even-numbered carbons of LA were labeled, indicative of de novo biosynthesis.•The odd-numbered carbons of (Z,Z)-6,9-heptadecadienewere labeled.•(Z,Z)-6,9-heptadecadiene is converted from LA after loss of the carboxyl carbon.