Hydrogen sulfide exposure increases desiccation tolerance in Drosophila melanogaster

Hydrogen sulfide (H2S) 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 H2S gas that emanated from a K2S donor. Using this bioassay system, we found that H2S exposure significantly increased the survival of flies under arid and food-free conditions, but not under humid and food-free conditions. This suggests that H2S 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 2 h when the flies transferred to the arid and food-free bioassay system. Addition of H2S 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 H2S regulates various physiological alterations.