Relationship between the activities of glutathione S-transferase and acetylcholinesterase of Blattella germanica and its resistance.

Objective To understand the relationship between the activities of glutathione S-transferase and acetylcholinesterase of Blattella germanica and its resistance,and then provide scientific evidence for the establishment of resistance detection by biochemistry.Methods The insecticide film was used to identify the resistance of German cockroach to four kinds of insecticides.The enzyme activity was tested by spectrophotometry.Results The resistance ratio of B.germanica to four insecticides was 1.08,2.35,7.47,10.92,respectively.GSTs activity of resistant strain was much higher than that of susceptibility strain,and the difference was very significant.AChE activity of resistant strain was lower than that of susceptibility strain,and the difference was significant.Conclusion B.germanica had high resistance to beta-cypermethrin and deltamethrin,and low resistance to DDVP and propoxur.The increase of GSTs activity could speed up the metabolism of pesticides,leading to the decrease of B.germanica susceptibility.AChE as an orgnaophosphorus and carbamate insecticides target enzyme,the decrease of the activity led to the decline of B.germanica susceptibility.The results indicated that the changes of enzyme activity had the close relationship with the development of resistance.