Insecticidal activity of periplocosides against oriental armyworm (Mythimna separata) and its effects on three characteristic enzyme activities in the midgut cell BBMV
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Abstract
The toxicity of six periplocoside compounds against 3th M. separata larvae was measured by toxic carrying leaf disc method, the activities of aminopeptidase, alkaline phosphatase and V-ATPase in BBMV were determined using six periplocoside compounds on the basis of preparing brush border membrane vesicles (BBMV) of oriental armyworm midgut cells by MgCl2 precipitation and differential centrifugation. The results showed that PSP and PST had obvious insecticidal activity with LC50 value of 1.60 and 1.23 mg/mL at 24 h, respectively. PSA, PSD and PSF revealed weak insecticidal activity (LC50 > 20 mg/mL) while PSE had no insecticidal activity. Six periplocosides had no significant inhibitory effect on aminopeptidase and alkaline phosphatase. The activity of V-ATPase was significantly inhibited by PSP and PST with a concentration dependence manner. Therefore, we preliminarily speculated that the initial binding site of insecticidal periplocoside compounds was located on the V-ATPase.
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