Effects of developmental age, ambient temperature, and dietary alterations on DELTA12 desaturase activity in the house cricket, Acheta domesticus.

摘要

Double bond formation in polyunsaturated fatty acids (PUFA) is mediated by desaturase enzymes. Certain insect species have been found to possess a DELTA12 desaturase, previously thought to occur exclusively in plants. We have begun to characterize this enzyme to determine its relatedness to those found in plants and animals. Desaturase activity can be altered significantly by a number of environmental factors in protozoa, cyanobacteria, plants, fish, and rats. We present evidence here that DELTA12desaturase activity in Acheta domesticus is affected by developmental stage, starvation, dietary alterations, and fluctuations in ambient temperature. Highest activity is observed during the middle of the penultimate instar and 3 to 6 days after adult emergence. Starvation markedly decreases DELTA12 activity, whereas resumption of feeding on fat-free or low fat diets increases activity.