Title

Mitochondrial antioxidant defence in radioresistant Lepidopteran insect cells

Authors

Shubhankar Suman^1,2, Rakesh Kumar Seth², Sudhir Chandna^1*

Affiliation

¹Natural 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

Email

sudhirchandna@yahoo.com

Article Type

Hypothesis

Date

Received April 01, 2009; Revised May 26, 2009; Accepted June 13, 2009; Published August 18, 2009

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.

Keywords

Mitochondrial DNA (mtDNA), Manganese-superoxide dismutase (Mn-SOD), Glutathione peroxidase (Gpx), Gluthathione reductase (GR), Glutathione S-transferase (GST), Thioredoxin peroxidase (TRPx) and Thioredoxin reductase (TR)

Citation

Suman et al, Bioinformation 4(1): 19-23 (2009)

Edited by

P. Kangueane

ISSN

0973-2063

Publisher

Biomedical Informatics

License

This is an Open Access article which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. This is distributed under the terms of the Creative Commons Attribution License.