Transcription profiles of heat shock protein 70 (HSP70) in Pardosa astrigera (Araneae: Lycosidae) in response to cadmium, endosulfan and temperature

We examined the effects of cadmium exposure and various stress on the expression of Pardosa astrigera heat shock protein 70 (HSP70). To do this, P. astrigera HSP70 gene was cloned and its sequence determined. Female spiders were long-term exposed to 40 mM CdCl2 or to 500 ppm polychlorinated biphenyls (PCB) for 2, 4 and 6 weeks, and short-term exposed to 10~1,000 ppm endosulfan for 24 hr by dietary uptake. Female spiders were also exposed to various temperatures for 3 h or for 7 days. Transcription profiles of HSP70 were determined by quantitative real-time PCR using EF-1α as reference gene for data normalization. HSP70 transcription gradually increased during 2, 4 and 6 weeks of exposure to cadmium. In particular, the expression level at 6 week exposure was 3.4-fold higher than that of untreated control. Transcript level of HSP70 was not significantly changed by PCB exposure. Exposure to endosulfan, however, resulted in down-regulation of HSP70 in a dose-response manner. In the short-term (3 h) temperature exposure, an increased expression of HSP70 was observed as temperature increased up to 30 °C and then slightly decreased at 35 °C. However, induction of HSP70 expression was not observed during the long-term (7 days) temperature exposure. Taken together, HSP70 gene appears to be up-regulated by cadmium and short-term high temperature whereas down-regulated by endosulfan, but not to be affected by long-term exposure of PCB and temperature. These results suggest that HSP70 could be useful as a biomarker for cadmium contamination at a molecular level.