Mitochondrial antioxidant defence in radio-resistantLepidopteran insect cells |
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Authors: | Shubhankar Suman Rakesh Kumar Seth Sudhir Chandna |
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Institution: | 1.Natural Radiation Response Mechanisms (NRRM) Group, Division of Radiation Biosciences, Institute of Nuclear Medicine & Allied Sciences, Brig S K Mazumdar Road, Delhi-110054, India;2.Department of Zoology, University of Delhi, Delhi-110007, India |
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Abstract: | Cells isolated from Lepidopteran insects (butterfly and moths) display very high radioresistance as compared to mammals and other insect
species. Since free radical induced mitochondrial damage under stress conditions is very crucial for cellular fate determination, antioxidant
system is the major protective modality required to minimize stress-induced damage and to modulate cellular sensitivity. In this study, we
predict the mitochondrial localization potential and co-existence of important antioxidant enzymes in insect cells and compare with other
radiosensitive (mammals, Dipteran insects) and radioresistant (nematodes) species. Our study clearly demonstrates the inter-species
variation in then localization potential of various antioxidant enzymes. A higher mitochondrial localization potential as a function of
mitoprot score was evident for all important antioxidant enzymes in the lepidopteran insect Bombyx mori (Mn-SOD, 0.694; GPx, 0.862;
TRPx, 0.997; TR, 0.9), besides an unusual mitochondrial localization prediction for catalase (0.453). We further found coexistence of
glutathione and thioredoxin system in the mitochondria of lepidopteran insects as also reported in various plant species. On the basis of
above observations, we hypothesize that a strong mitochondrial antioxidant enzyme system including the unusual coexistence of catalase,
glutathione and thioredoxin system may help minimize the free radical mediated damage to mitochondria and can contribute to the intrinsic
radioresistance of lepidopteran insects. |
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Keywords: | Mitochondrial DNA (mtDNA) Manganese-superoxide dismutase (Mn-SOD) Glutathione peroxidase (Gpx) Gluthathione reductase (GR) Glutathione S-transferase (GST) Thioredoxin peroxidase (TRPx) Thioredoxin reductase (TR) |
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