The effects of perfusion on the synthesis and release of blood proteins by diapausing pupae of the Cecropia silkworm

Abstract

The present report examines factors that regulate the rates of blood protein synthesis and rlease in the Cecropia silkworm. Techniques are described which permit measurements of the concentration and rates of synthesis of individual blood proteins. A novel feature of the experiments was an analysis of the effects of perfusion. Diapausing pupae were perfused with Ringer's solution until their blood contained only one-sixth of the original protein content. The reconstitution of the protein components in the blood was followed over several weeks by acrylamide gel electrophoresis, densitometry, and isotope incorporation. This reconstitution was accomplished by two principal mechanisms. One mechanism was the continued synthesis and release of the major protein components found normally in pupal blood. Another mechanism was the synthesis and release of proteins (possibly larval) not normally found in pupal blood. Within a week after perfusion these new proteins accounted for about 30 per cent of the total blood proteins. It was discovered that there were no pupal-specific blood proteins: all blood proteins found in the pupa were also found in larva or adult.