Abstract
Toxic effects of cadmium (Cd), a common soil pollutant, are still not very well understood, particularly in regard to its epigenetic impact. Therefore, the aim of this study was to assess DNA methylation changes and their persistence in the earthworm Lumbricus terrestris upon chronic low dose Cd exposure using methylation sensitive amplification polymorphism (MSAP). Moreover, the biomarker response and fitness of the earthworms, as well as the expression of detoxification-related genes (metallothionein (MT) and phytochelatin synthase (PCS)) was evaluated. Low levels of Cd caused an increase in genome-wide DNA methylation, which remained partly modified, even after several months of recovery in unpolluted soil. Increased cellular stress seemed to decrease after two weeks of exposure whereas fitness parameters remained unaffected by Cd, probably as a result from the activation of detoxification mechanisms like the expression of MTs. Interestingly, even though the level of Cd exposure was very low, MT expression levels indicate the development of acclimation mechanisms. Taken together, this study demonstrates that acclimation, as well as epigenetic modifications can occur already in moderately polluted environments. In addition, these effects can have long-lasting impacts on key species of soil invertebrates and might persist long after the actual heavy metal challenge has passed.
Highlights
Terrestrial ecosystems have been challenged in the past decades through a growing industry and agriculture and, along with that, an increase in soil pollution
In the present study we assessed the impact of environmentally relevant, low concentration of Cd on terrestrial ecosystems using L. terrestris as an experimental model
Changes at the organismic level as well as molecular and cellular responses and epigenetic modifications were studied over 12 weeks
Summary
Terrestrial ecosystems have been challenged in the past decades through a growing industry and agriculture and, along with that, an increase in soil pollution. Cadmium (Cd), one of the main soil pollutants, is brought into the environment mainly as a side product in the metal and mining industry, through airborne deposition, and from the usage of Cd-containing fertilizers [1]. Cd is widely applied in laboratory experiments to study the effect of soil pollution on terrestrial organisms like earthworms, which are, through their soil dwelling lifestyle, well suited to examine the adverse outcome of environmental stress. The exact mechanisms of Cd toxicity are not well understood, in invertebrates.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
