Soluble acid phosphatases of the hemolymph and fat body of Calpodes ethlius (Stoll) and the control of protein storage by fat body

Abstract

Hemolymph proteins of fifth-instar larvae of Calpodes ethlius were separated by precipitation with ammonium sulfate, followed by column chromatography on DEAE-cellulose. The three main proteins (antigens) of the larval hemolymph were present in varying amounts in all fractions precipitated by ammonium sulfate. Two of these antigens (1 and 2) were isolated by column chromatography. Acid phosphatase activity of hemolymph and fat body proteins was assayed by electrophoresis and colorimetry. Enzyme activity varied with stage of development in the fifth instar. In the hemolymph, activity declined along with protein concentration towards the end of larval growth. In the fat body, enzyme activity was highest during the main synthetic phase, and declined just before the start of protein uptake and storage. The activity rose again during the period of massive uptake of blood proteins. This increase may reflect storage of hemolymph phosphatases, and may also be correlated with the phase of heterophagy and autophagy which immediately precedes pupal ecdysis.