Chromosomal puff induction in salivary glands from Drosophila hydei by arsenite

Abstract

During incubation of salivary glands from Drosophila hydei in the presence of arsenite (7.5 × 10 −5 M) the major temperature-sensitive puffs show essentially the same kinetics of development as after anaerobiosis followed by air or during temperature shock. Also the dose-response curve, the labeling intensity after a [ 3H]uridine pulse and the electronmicroscopic features of the temperature-sensitive chromosome regions are virtually the same during arsenite treatment as those obtained with other treatments. However, one major difference between incubation with arsenite and the other treatments is found in the changes in ATP level. During arsenite treatment the ATP level does not change, whereas during the other treatments the ATP level is reduced. In an attempt to correlate puff-inducing events with changes in the mitochondrial metabolism, the affinity of the α-glycerophosphate oxidase was measured and the related changes in the α-glycerophosphate concentration were studied. During all puff-inducing treatments studied so far, thus also during arsenite treatment, a decrease in affinity of the α-glycerophosphate oxidase and a decrease in α-glycerophosphate concentrations is found in the first 15–20 min of the incubation. Later the concentration of α-glycerophosphate increases again, possibly due to the further decrease in affinity of α-glycerophosphate oxidase.