Effects of electroshocking and allyl isothiocyanate on biomarkers of the earthworm species Eisenia andrei – Possible side-effects of non-destructive extraction methods

Earthworms contribute to the functioning and stability of soil processes which are equally fundamental to both forestry and agriculture. Earthworms are generally exposed to chemicals present in their terrestrial environment and have been used for assessing the chemical environmental pollution. Reliable and efficient extraction methods are required for studies of earthworms. However, when ecotoxicological and biomonitoring studies are conducted, besides the efficacy, it is also important that the extraction method does not influence the physiological status of the earthworms. Allyl isothiocyanate (AITC) application and the electrical octet method are non-destructive alternative extraction methods. The focus of this research was to investigate effects of electroshocking and AITC on molecular biomarkers in earthworms, since there is no data about possible side effects of these methods on physiological status of earthworms. Therefore, an experimental study was conducted using the earthworm species Eisenia andrei earthworms and the activities of acetylcholinesterase (AChE), catalase (CAT) and efflux pump were measured. Measurements showed that exposure to AITC on filter paper and direct application of electricity significantly affected measured biomarkers. Electroshocking caused decrease in AChE activity, whereas AITC caused decrease of AChE activity, as well as increase of CAT activity and increase in efflux pump activity. The obtained results demonstrate that these extraction methods could influence the physiological status of earthworms and therefore are unsuitable for ecotoxicological research and biomonitoring studies when sampled earthworms are used for biomarker measurements.

► Electroshocking caused decrease in AChE activity.
► Partial recovery of AChE activity 60 min after electroshocking.
► Decrease in AChE, and increase in CAT and efflux activity after exposure to AITC.
► These extraction methods affect physiological status of earthworms.