Changes in Thiol Content, Glutathione and Hydrogen Peroxide Levels as a Measure of Oxidative Stress in Periplaneta Americana Treated with Metarhizium Anisopliae Spp.

Periplaneta americana (American cockroach) treated with conidia of entomopathogenic fugal isolates of Metarhizium anisopliae revealed a decrease in the thiol content and an increment in the levels of oxidized glutathione as well as hydrogen peroxide (H2O2). T-SH levels decreased to 48% and 50% at 24 hours and 48 hours post treatment respectively at LC90 of M20 isolate. Low virulent isolate M48, on the other hand, recorded a decrease of 76% and 78% in the T-SH levels at 24 and 48 hours post treatment respectively with LC30 treatment. Remarkable increase of 200% in the levels of H2O2 recorded at LC90 of M20 and 102% increase at LC30 of M19 was remarkable and focuses on the extent of oxidative stress induced by the fungal infection. Dynamics in the levels of GSH, GSSG, H2O2 and thiols in the insects treated with different fungal isolates in a time and dose dependant manner reveals oxidative stress induced by the fungal infection and the information would facilitate to explore the antioxidant defense system in augmented resistance or susceptibility of cockroach against entomopathogenic fungal conidia.