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(58-09) Stimulation of energy reserves as an early warning biomarker for Folsomia candida. Staempfli, Carine1, Becker-van Slooten, Kristin*,1, Tarradellas, Joseph1, 1 DGR-GECOS-Ecotoxicologie, Lausanne, Switzerland ABSTRACT- The aim of this study was to investigate the effects of the pesticide dinoseb on life cycle parameters and on biomarker responses of the soil organism Folsomia candida in order to establish a relationship between short term (biomarkers) and long term effects (reproduction). Juveniles (10-12 days) were exposed to compressed artificial soil contaminated with dinoseb. At different time intervals (max. 60 days), mortality, reproduction, length, weight, lipid and protein content (spectrophotometrical methods) and Hsp70 induction (Western blot) were determined. After six days of exposure to 15-30 Key words: collembola, biomarkers, Folsomia candida, energy allocation |
g/g of dinoseb, the measured biomarkers (length, weight, lipid and protein content) were increased in the exposed organisms compared to the control. This stimulation seems to indicate that collembola exposed to dinoseb adopt a strategy consisting in stimulating their growth in order to reach sexual maturity more rapidly and to improve their reproduction. This hypothesis was confirmed by the fact that the number of eggs was not affected (only the number or juveniles). The increase in lipid reserves could result in the production of bigger or more eggs. Furthermore, the increase in protein synthesis and the induction of Hsp70 may reflect an activation of the detoxification and cell reparation mechanisms. Temporal analysis showed that after 21 days all the measured biomarkers (except for proteins) decreased. We hypothesise that after having made an important effort to reach sexual maturity, the organisms will decrease the energy allocated to growth in favour of defence mechanisms. The consequence is a decrease of their length, weight and lipid content and an increase of protein content. In the case of dinoseb, the selected biomarkers do not allow to detect an effect at a lower concentration than the classic endpoint reproduction, but the observed stimulation can be a pertinent early effect indicator.