The proposed research is to select and set up a battery of biomarkers to be applied on the wax moth (Galleria mellonella) as an environmental indicator for assessing the toxicity of cadmium-contaminated areas. This insect specie is traditionally used as a model in many biological and ecological studies because of its easiness breeding in laboratory, repeated generations during the year and its plasticity for developing and optimizing eco-toxicological assays. It is reasonable that multiple bioassays may provide more reliable data to evaluate simultaneously the effects of the environmental conditions on several biological parameters avoiding false positive/negative results. We suppose that antioxidant and detoxification systems play an important role in the defense mechanisms against cadmium and other xenobiotics which endogenously produce reactive oxygen species (ROS) in several insects. Therefore, the activities of superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST), the content of malondialdehyde (MDA) and ROS production were tested in sixth larval instar of wax moths fed with artificial diet containing 10 and 100 ppm of cadmium. Cadmium contamination resulted in changes of haemolymph enzymatic activities. The activities of SOD and GST were higher in cadmium-treated groups compared to untreated and the content of MDA (indicator of oxidative stress) gave the same results. On the other hand, the activity of CAT showed a slight decrease after cadmium treatment. The production of hydrogen peroxide analyzed by the Amplex Ultra Red assay showed a decrease in cadmium-treated groups compared to untreated. Cadmium reduced larval weight in both applied concentrations and larvae treated by 100 ppm of cadmium showed also a delay in their development. The SOD, GST, CAT and MDA biomarkers showed certain sensitivity to cadmium. We infer from these findings that dietary cadmium activates insect antioxidant enzymatic responses.
Wax moth (Galleria mellonella) as a bio-indicator model in ecotoxicological studies on cadmium
DE LILLO, Enrico;
2012-01-01
Abstract
The proposed research is to select and set up a battery of biomarkers to be applied on the wax moth (Galleria mellonella) as an environmental indicator for assessing the toxicity of cadmium-contaminated areas. This insect specie is traditionally used as a model in many biological and ecological studies because of its easiness breeding in laboratory, repeated generations during the year and its plasticity for developing and optimizing eco-toxicological assays. It is reasonable that multiple bioassays may provide more reliable data to evaluate simultaneously the effects of the environmental conditions on several biological parameters avoiding false positive/negative results. We suppose that antioxidant and detoxification systems play an important role in the defense mechanisms against cadmium and other xenobiotics which endogenously produce reactive oxygen species (ROS) in several insects. Therefore, the activities of superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST), the content of malondialdehyde (MDA) and ROS production were tested in sixth larval instar of wax moths fed with artificial diet containing 10 and 100 ppm of cadmium. Cadmium contamination resulted in changes of haemolymph enzymatic activities. The activities of SOD and GST were higher in cadmium-treated groups compared to untreated and the content of MDA (indicator of oxidative stress) gave the same results. On the other hand, the activity of CAT showed a slight decrease after cadmium treatment. The production of hydrogen peroxide analyzed by the Amplex Ultra Red assay showed a decrease in cadmium-treated groups compared to untreated. Cadmium reduced larval weight in both applied concentrations and larvae treated by 100 ppm of cadmium showed also a delay in their development. The SOD, GST, CAT and MDA biomarkers showed certain sensitivity to cadmium. We infer from these findings that dietary cadmium activates insect antioxidant enzymatic responses.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
