NATURAL AGING AND RADIATION-INDUCED LIFE SHORTENING IN DROSOPHILA MELANOGASTER

Various tissues of control and gamma-irradiated male Drosophila melanogaster have been investigated by light and electron microscopy. Old flies showed involutionary changes in the fat body, oenocytes, muscle, mid-gut, Malpighian tubules, brain and sex organs. There was an accumulation of electron-dense bodies in the oenocytes and of ceroid-like material in the cytoplasm of the mid-gut cells. Also, senescent flies showed a striking reduction in the ribosomes and endoplasmic reticulum in the Malpighian tubules. In 28-33-day-old flies which were exposed to 50 kR of gamma-irradiation at 1 day of age, the most consistent pathological changes were focal cytoplasmic edema and virus accumulation in the nuclei. Our present results support the view that irradiation results in life-shortening through a radiation syndrome mechanism which is essentially unrelated to aging.