engleski

Epigenetic alterations in heavy metal stressed earthworms

Emerging evidence suggests that soil heavy metal pollution can alter epigenetic marks in soil fauna, with DNA methylation as one of the underlying mechanisms - a process which can be persistent and even heritable. The aim of this study was to assess the consequences of chronic heavy metal exposure on genome wide DNA methylation in the earthworm Lumbricus terrestris. Earthworms were exposed to low (10 mg/kg) environmentally relevant concentration of cadmium (Cd) for a period of 3 months. Through the exposure period, the overall health status of the earthworms was monitored at the cellular (DNA damage, oxidative stress, lipid damage) and organismic level (fitness, reproductive success). Genome wide DNA methylation status was assessed by methylation sensitive amplification polymorphism (MSAP) at the beginning of the exposure and after 1 and 3 months exposure. During the exposure, earthworm fitness and cellular mechanisms remained unaffected by Cd. However, on the epigenetic level, already after 1 month of exposure, Cd induced significant increase in DNA methylation, which remained constant until the end of the exposure. The results of this study demonstrate that low levels of environmental pollution can lead to the occurrence of subtle epigenetic modifications, even when no impacts on the cellular and organismic level can be observed.

DNA methylation, earthworms, cadmium

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