[Biochemistry of the developmental cycle of Triatoma infestans (Vinchuca). 2. Biosynthesis of fatty acids].

The biosynthesis of fatty acids in Triatoma infestans was studied in all the nymph stages and adult insects by feeding experiments with 1-14C acetate. In other experiments labeled acetate, 1-14C palmitate or 1-14C stearate were injected in the abdomen. In another group of experiments the abdominal non intestinal tissue of adult insects was homogenized and the supernatants of 10 000 X g and 105 000 X g were incubated with 1-14C acetyl-CoA. The incorporation of the labeling in the fatty acids was studiel by gas liquid radiochromatography. It was proved that the supernatant of 105 000 X g possessed a fatty acid synthetase able to synthesize de novo the saturated fatty acids of 10 to 18 carbons with a maximal yield in the myristic and palmitic acids. The fatty acid synthetase was active from Nymph L stage. The supernatant of 10 000 X g was able to synthesize fatty acids tentatively identified as eicosenoic and eicosadienoic acids. The T. infestans has also an enzyme that elongated palmitate to stearate. In the fraction precipitable between 10 000 X g and 105 000 X g was apparently present a desaturating enzyme that converts saturated to monoethylenic acids. The enzyme was apparently only active from Nymph II stage.