Abstract
Hydrogen sulfide (H(2)S) has been shown to effect physiological alterations in several animals, frequently leading to an improvement in survival in otherwise lethal conditions. In the present paper, a volatility bioassay system was developed to evaluate the survivorship of Drosophila melanogaster adults exposed to H(2)S gas that emanated from a K(2)S donor. Using this bioassay system, we found that H(2)S exposure significantly increased the survival of flies under arid and food-free conditions, but not under humid and food-free conditions. This suggests that H(2)S plays a role in desiccation tolerance but not in nutritional stress alleviation. To further confirm the suggestion, the mRNA levels of two desiccation tolerance-related genes Frost and Desat2, and a starvation-related gene Smp-30, from the control and treated flies were measured by quantitative real-time PCR. These genes were up-regulated within 2h when the flies transferred to the arid and food-free bioassay system. Addition of H(2)S further increased Frost and Desat2 mRNA levels, in contrast to Smp-30. Thus, our molecular results were consistent with our bioassay findings. Because of the molecular and genetic tools available for Drosophila, the fly will be a useful system for determining how H(2)S regulates various physiological alterations.
