FINE STRUCTURAL AND BIOCHEMICAL STUDIES ON CELL DEATH OF THE DEVELOPING <i>BAR</i> EYE DISCS IN <i>DROSOPHILA MELANOGASTER</i>

Abstract

The aspects of degeneration in the Bar eye discs at various developmental stages of Drosophila melanogaster was elucidated microscopically and biochemically. Acid phphosatase was identified histochemically in lysosomes or their derivertives in the degenerating area of the 85-95 hour eye discs. The enzyme reaction appeared to localize selectively in the single membrane-bounded structure or myelin-like figure. The cell debris probably resulting from the resolving process, fail to demonstrate any enzyme activity at the prepupal stage.Biochemical data indicated that the maximum activities of acid phosphatase were shown in eye discs at the 95-hour stage. This is in contrast to the weak acid phosphatase activity detected in eye discs of prepupal stage. However, whole larval homogenates showed maximum value of acid phosphatase activity at the same stage and the post embrionic development. This causal association of increased enzyme activity and histochemical observation in the resolving process of the eye discs suggests that the process of degeneration may be mediated by the lysosome activity, either by the formation of lysosomes or by the synthesis of hydrolytic enzymes. These lysosomes or activities of lysosomal lytic enzyme were reduced by treatment with acetamide. These data suggest that acetamide may act to inhibit the formation of lysosome or the synthesis of hydrolytic enzyme in the Bar eye discs.