The fine structural morphology of the midgut of aged Drosophila: a morphometric analysis

The midguts of 1-day and 72 day-old fruitflies were examined morphometrically at the electron microscopic level. The major alterations noted were that the number of supranuclear mitochondria decreased by approximately 50%, while the volume of individual mitochondria doubled as a function of age. Moreover, approximately 29% of the nuclear volume of old flies, was occupied by inclusion bodies as was 19% of the supranuclear cytoplasmic volume. Additionally, the surface density of rough endoplasmic reticulum was reduced to more than half that of young flies. It is suggested that the functional capability of the parenchymal cells become debilitated due to the presence of these inclusion bodies, and that the cell's ability to manufacture proteins and produce energy are seriously hindered by the mitochondrial alterations and reduction in the surface density of the rough endoplasmic reticulum.