Impact of two insect growth regulators on the enhancement of oxidative stress and antioxidant efficiency of the cotton leaf worm, Spodoptera littoralis (Biosd.) | ||||
| Egyptian Academic Journal of Biological Sciences. A, Entomology | ||||
| Article 14, Volume 5, Issue 1, April 2012, Page 137-149 PDF (187.85 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/eajbsa.2012.14956 | ||||
 View on SCiNiTO | ||||
| Author | ||||
| Nedal M. Fahmy | ||||
| Plant Protection Resarch Institute, Agricultural Research Center. Giza, Egypt | ||||
| Abstract | ||||
| The present study was conducted for evaluating of the impact of two insect growth regulators (IGRs) namely, Applaud (buprofezin) as a chitin synthesis inhibitor and Admiral (pyriproxyfen) as juvenile hormone analogue (JHA) in the larval body of the cotton leaf worm, Spodoptera littoralis. This evaluation was achieved via (1) Estimating the antioxidant system response present in the 4th larval instar of S. littoralis through estimating the activity of two enzymes; catalases (CAT) and glutathione-S-transferase (GST), as well as an antioxidant compound; glutathione reduced (GSH). (2) Estimating the accumulated lipid peroxidation in the larval tissues by evaluating the level of Malonaldehyde (MDA) as an indicator for lipid peroxidation. Both tested IGRs used in this study showed more or less similar trend in their mode of action relative to the tested biomarkers in the present work. CAT showed a significant increase in its activity (42.02%) and (139.26%) for buprofezin and pyriproxyfen, respectively. This activity lasts for only one day post treatment then it was inhibited to be very close to that level in normal untreated larvae. This may be due its consumption in scavenging reactive oxygen species (ROS) produced due to significant accumulation of MDA. One the other hand, GST showed persisted increase in its activity especially with buprofezin treated larvae may be to overcome the deleterious effect of accumulating MDA. Similarly, GSH which serves as a free radicals scavenger also showed a significant increase in its level especially due to treatment. The present study which is conducted for the first time, documented the occurrence of lipid peroxidation due to IGRs treatment in the larval tissues in S. littoralis larvae which enhanced different antioxidant defensive system to overcome its effect. | ||||
| Keywords | ||||
| Insect Growth Regulators; Spodoptera littoralis (Biosd.) | ||||
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