The changes of four enzyme activities of Galleria mellonella larvae infected by entomopathogenic nematode Heterorhabditis beicherriana

To understand the lethal mechanisms of Heterorhabditis beicherriana on insect and the stress response of the insect infected by this nematode, the four enzymes of tyrosinase (TYR), acetylcholinesterase (AChE), carboxylesterase (CarE) and glutathione s-transferase (GSTs) were analyzed in this study to observe the enzyme activity changes in Galleria mellonella infected by H. beicherriana. The results showed that the infection of H. beicherriana could increase the activity of four enzymes while the doses of the nematode increased within 20-80 IJs/larva. TYR activity at 40 h was 6.57, 7.94, 8.12 times of that at 0 h under the infection doses of 20, 40 and 80 IJs/larva, respectively, which companied with the colors of G. mellonella corpses darkening gradually with increasing of death time. The activities of AChE, CarE and GSTs at 40 h decreased in different degrees compared with the values at 32 h. The results indicated that the increase of these four enzyme activity could enhance G. mellonella detoxification or resistance on the nematodes and symbiotic bacteria in vivo.