Genetical and biochemical studies on amylase in Drosophila melanogastet

Abstract

1. Amylase activity in D. melanogaster varies according to strains; the activity of Hikone-AS (H) is always stronger than that of Oregon-R (iso) (O).
2. Hybrids between the two strains show an intermediate activity of the parents. Judging from the result of H×O and of O×H, it is assumed that the amylase activity is not controlled by a sex-linked gene.
3. In both H and O strains, the amylase activity in eggs is very weak, the activity in larval stage, especially in the third instar larvae shows the highest value, then it decreases suddenly just after the pupation, and maintains nearly a constant value till the adult stage.
4. As far as experimental results show, amylase activities of the digestive and body fluids in larval and adult stages, seem to be controlled by the same gene.
5. When starch is added to the medium which contains little starch, the amylase activity in the adult stage increases as compared with that of the control.