Abstract

To investigate the mechanism of Galleria mellonella infected with entomopathogenic nematodes (EPNs), we studied the effects of a new species of EPNs, Heterorhabditis beicherriana n.sp., on the activities of Tyrosinase (TYR), acetylcholinesterase (AChE), carboxylesterase (CarE) and glutathione S-transferase (GST) in whole body of G. mellonella. The last instar larvae of G. mellonella (0.18 to 0.20 g/larva) were used as host insects and were randomized into four groups (n = 60 in each group): 0 IJ/larva control group, 20 IJs/larva group, 40 IJs/larva group and 80 IJs/larva group. Infective juveniles (IJs) were injected into each selected G. mellonella larva. At 0, 8, 16, 24, 32 and 40 h post-infection, ten injected larvae were randomly collected from each group, enzymes were extracted, and the enzyme activities of TYR, AChE, CarE and GSTs were assessed following standard methods. We found that the activities of TYR, AChE, CarE and GST were significantly enhanced in a dose-dependent manner in G. mellonella larvae infected with H. beicherriana, which may be the overeactive stress response to the EPNs infection and the overreaction could lead to the death of host insects.

Key words: Entomopathogenic nematode, Galleria mellonella, tyrosinase, acetylcholinesterase, carboxylesterase, glutathione S-transferase.