FIRST RECORD OF COLLEMBOLANS CARBOXYLESTERASE AND GLUTATHIONE-S-TRANSFERASE ACTIVITIES EXPOSED TO SEVERAL PESTICIDES
AHMED MOHAMMED ALI HAMMAD *
Department of Crop Protection, Faculty of Agriculture, University of Khartoum, Khartoum, Sudan and Discipline of Plant Pathology, School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, South Africa
AZZA SIDDIG HUSSIEN ABBO
Department of Crop Protection, Faculty of Agriculture, University of Khartoum, Khartoum, Sudan.
AZHARI OMER ABDELBAGI
Department of Crop Protection, Faculty of Agriculture, University of Khartoum, Khartoum, Sudan.
MARK LAING
Discipline of Plant Pathology, School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, South Africa.
*Author to whom correspondence should be addressed.
Abstract
Collembolans are small animals live in dead vegetation and consumers of dead plant material. Carboxylesterases (CarbEs) and glutathione transferase (GST) play a key role in the detoxification of many agrochemicals. To gain knowledge on the role of CarbEs and GST activities in the natural tolerance in collembolan insects, we performed enzyme kinetic analyses to determine whether collembolans are able to generate these enzymes in their bodies after exposure to chemicals. The aim of this study also was to explore the effects of repetitive applications of a mixture of pesticides upon CbE and GST of springtails in order to increase the understanding on pesticide detoxification enzymes in this organism. Our studies provide a baseline study on the impact of various agrochemicals on the levels of the detoxification enzymes for collembolans. Application of pesticides such as Bordeaux mixture, imidacloprid, methiocarb and glyphosate resulted in significant increases of CarbEs in collembolan insects. Polyacrylamide gel electrophoresis (PAGE) of CarbE levels revealed visible stronger bands in the response of collembolans to all the applied pesticides, compared to control. A significant increase in glutathione S-transferases (GST) activity was recorded only after application of Bordeaux mixture. The data presented in this study illustrate the impact of various pesticides on the levels of relevant detoxification enzymes such as CarbE and GST in collembolan insects.
Keywords: Collembola, carboxylesterase, glutathione-S-transferase, polyacrylamide gel electrophoresis, pesticides