Fluorescent Products and Lysosomal Components in Aging Drosophila melanogaster

Abstract

An electron microscopic study was performed on the brain and visceral organs of Drosophila melanogaster ranging in age from 7 to 102 days. The subcellular localization of acid phosphatase was determined by the Gomori technique and the level of fluorescent products was measured by spectrophotofluorometry performed on chloroform-methanol extracts of whole flies. It was found that the tissues of aged Drosophila melanogaster contain abundant lipopigments that occasionally fill up to 50% of the cytoplasmic volume. The pigments have the fine structural characteristics of lipofuscin or ceroid and, in chloroform-methanol extracts, show fluorescence with maximal excitation at 370-375 nm and maximal emission at 440-450 nm, which is similar to the fluorescence of the lipofuscin from aged mice. Lysosomal participation in the genesis of the Drosophila pigment is suggested by the demonstration of acid phosphatase activity in the dense bodies present in the midgut epithelium.