Abstract Chemical analyses of the environment can document
contamination by various xenobiotics, but it is also
important to understand the effect of pollutants on living
organisms. Thus, in the present work, we investigated the
effect of the pesticide imidacloprid on the detoxifying enzyme
glutathione S-transferase (GST) from Folsomia candida
(Collembola), a standard test organism for estimating the effects
of pesticides and environmental pollutants on non-target
soil arthropods. Test animals were treated with different concentrations
of imidacloprid for 48 h. Changes in steady-state
levels of GST messenger RNA (mRNA) and GST enzyme
activity were investigated. Extracted proteins were separated
according to their sizes by sodium dodecyl sulfatepolyacrylamide
gel electrophoresis, and the resolved protein
bands were detected by silver staining. The size of the glutathione
(GSH) pool in Collembola was also determined. A
predicted protein sequence of putative GSTs was identified
with animals from control group. A 3-fold up-regulation of
GST steady-state mRNA levels was detected in the samples
treated with 5.0 mg L−1 imidacloprid compared to the control,
while a 2.5- and 2.0- fold up-regulation was found in organisms
treated with 2.5 and 7.5 mg L−1 imidacloprid, respectively.
GST activity increased with increasing imidacloprid
amounts from an initial activity of 0.11 μmol min−1 mg−1 protein
in the control group up to 0.25 μmol min−1 mg−1 protein
in the sample treated with the 5.0 mg L−1 of pesticide. By
contrast, the total amount of GSH decreased with increasing