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(W/MF159) Instability of Hsp 70 and its induction by a pesticide in Folsomia candida. Staempfli, Carine1, Becker-van Slooten, Kristin1, Tarradellas, Joseph1, 1 ABSTRACT- The heat shock protein Hsp 70 has been shown to be a promising biomarker in aquatic and terrestrial organisms. However, its analysis in the terrestrial insect Folsomia candida (collembola) poses many problems as the protein is particularly unstable in this species. Western blotting showed that the principal degradation fragment has a size of 48 kDa. We developed a western blot method (adapted from Koehler, University of Tuebingen, Germany) which enabled to avoid the degradation of Hsp 70 and which was successful in detecting the protein in Folsomia candida after a heat shock (12, 18 and 24 hours at 32°C). In the second part of the work the springtails were exposed to artificial compressed soil contaminated with the dinitrophenol dinoseb (10, 15 and 20 ug/g dry weight (DW)). Hsp 70 was analysed in pooled samples (40 to 150 collembola according to the age) after 1, 2, 3, 4, 5, 6, 7, 11 and 14 days. The only significant induction was observed after 5 days at 20 ug/g DW of dinoseb. The induction patterns over time were dissimilar for the different concentrations and a relatively high variability between the replicates was observed. Our results show that we must be cautious when interpreting biomarker and especially Hsp 70 results. Key words: heat shock proteins, biomarker, collembola, dinoseb |
