Protein synthesis and nucleic acid metabolism in the fat body of the larva of the blowfly, Calliphora erythrocephala

Abstract

The effect of culturing blowfly larvae at a low temperature (10°-larvae) for part of their larval period on the rate of protein synthesis by the fat body was investigated. In 10°-larvae this treatment prevented the rapid decline in protein synthesis which is seen in fat body from larvae cultured at 25°C for the whole of their larval period (25°-larvae). Protein synthesis in fat body from 25°-larvae was completely inhibited by 10 −4 M dinitrophenol, 7·8 × 10 −3 M chloramphenicol, and 10 −5 M cycloheximide. The RNA-P content per fat body from 25°-larvae increased from 2·8 to 14·0 μg over the age range 3 to 7 days and the protein content increased from 0·8 to 2·3 μg over the same period. Electron micrographs showed that fat body from 4-day-old 25°-larvae contained fat droplets, mitochondria, glycogen granules, and numerous ribosomes. On the other hand, fat body from 7-day-old larvae contained numerous albuminoid granules, but hardly any mitochondria and few ribosomes.