Cadmium toxicity to animals depends on their tolerance mechanisms. The harmful action of this metal takes different forms, starting from blocking of intracellular signalling receptors, through induction of oxidative stress, to genotoxic effects.
Cadmium tolerance developed in an unique strain of the moth Spodoptera exigua selected for over 170 generations in Institute of Biology, Biotechnology and Environmental Protection, University of Silesia in Katowice can be based on many mechanisms at both: cellular and molecular level. It cannot be excluded that multigenerational exposure to Cd may lead to the selection of insects that have a wider tolerance to oxidative stress.
Reactive Oxygen Species (ROS) are molecules present in cells undergoing oxidative stress. Oxidative stress level was measured in the hemolymph and midgut cells of the 5th larval stage after 1–6, 12, 18 and 24 generations of differential cadmium exposure in comparison with insects after multigenerational exposure (170 generations) and control strain. The assay used in present studies was to detect the relative percentage of cells that are ROS negative and positive. Thanks that, two populations of cells can be distinguished: live (ROS-) cells and cells exhibiting ROS (ROS+).
The pattern of the cell populations percentage/ratio in both hemolymph and midgut cells depend on the concentration of this metal in the food and the time of Cd exposure.
Dr. Monika Tarnawska is working in the Institute of Biology, Biotechnology and Environmental Protection, University of Silesia in Katowice, Poland. Major scientific interests of her are: ecotoxicology of terrestrial invertebrates, especially crop pests, activity and immunodetection of general stress proteins. Results of her works are published in prestigious journals, including: Fish & Shellfish Immunology, Chemosphere, Ecotoxicology, Ecotoxicology and Environmental Safety, International Journal of Pest Management and others.