Electron spin resonance spectroscopic studies of free radical generation and tissue specific catalase gene expression in Spodoptera litura (Fab.) larvae treated with the mycotoxin, destruxin

Destruxin recovered from Metarhizium anisopliae (Metch.) is insecticidal in nature. In the present study, a marked increase in the levels of superoxide radical and NADPH dependent superoxide radical in the partially purified destruxin treated larvae of Spodoptera litura (Fab.) was observed in a dose and time dependent manner. The ESR spectrum of the hydroxyl radical in the treated S. litura larvae depicted a time and dose dependent increase in the free radical level. Transcript abundance of catalase gene in S. litura larvae treated for 1, 24 and 48 h was investigated in the whole body. The same was studied in a temporal fashion i.e. midgut, fat body, salivary gland, Malphigian tubule and haemocytes of S. litura. The maximum catalase transcript level was observed in the fat body which is a detoxifying organ and the least in salivary gland which was prone to maximum damage upon exposure to the toxin.