Cytochrome P450 and Detoxifying enzymes
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anglais
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fourni par EOL authors
M. malcolmsonii is an omnivorous bottom dwelling fresh water prawn. Common name of this prawn is monsoon river prawn. It feeds on decomposing plants and animals, small worms, insects and their larvae. They are also cannibalistic in nature and may consume freshly molted co- species. In Asian countries particularly in India, Pakistan and Bangladesh the freshwater prawn species Macrobrachium malcolmsonii, M.rosenbergii and M. gangeticum are of special interest for aquaculture. M.malcolmsonii is nocturnal in habit and feed more actively at night. Being an indigenous fresh water river species M. malcolmsonii is more tolerant to environmental fluctuations and comparatively more resistant to contaminants. Males grow bigger than females, and even in the same sex there exists heterogeneity in growth. Those that grow faster tend to become dominant, while others remain stunted (1). Detoxifying enzymes such as antioxidant and cytochrome P450 enzymes play a main role in aquatic organisms in the removal of toxic compounds from their body. Activities of antioxidant enzymes were analysed in freshwater prawn Macrobrachium malcolmsonii during embryonic and larval development. An elevated level of antioxidant enzymes was encountered in the larval stage of M. malcolmsonii when compared to its preceding embryonic stages. It is suggested that when the larvae hatched out from the embryo it may exposed to hyperoxygen condition and there may be a chance for facing oxyradicals in aquatic environment. In order to detoxify these oxyradicals an enhanced level of antioxidant enzymes were found in malcolmsonii larvae.(2) Cytochrome P450 is a hemeprotein involved in the metabolism of xenobiotic compound. It has been extensively studied and reported that induction of cytochrome P450 protein related ethoxyresorufin –O- deethylase (EROD)enzyme is successfully involved in the metabolism of polycyclic aromatic hydrocarbons in fishes. CYP 450 related EROD enzyme is widely used as biomarker to organic pollution in marine environment. There is no detailed information available on aquatic invertebrates about the existence of ethoxyresorufin o deethylase (EROD) enzyme. Researchers made an attempt to find out the presence of EROD activity in malcolmsonii larvae and adult species. They reported the presence of EROD activity in the larvae, sub-adults and adults of the crustacean, Macrobrachium malcolmsonii and suggested that CYP450 and related monooxygenase enzymes could be used as a biomarker to organic pollution (3,4,5)
