Journal of Applied Entomology (2006) 130, 251-256

W. Dou, J.-J. Wang and Z.-M. Zhao (2006)
Toxicological and biochemical characterizations of GSTs in Liposcelis bostrychophila Badonnel (Psocop., Liposcelididae)
Journal of Applied Entomology 130 (4), 251-256
Abstract: The toxicological and biochemical characteristics of glutathione S-transferases (GSTs) in the resistant and susceptible strains of Liposcelis bostrychophila were investigated. The two resistant strains were the dichlorvos-resistant strain (DDVP-R) and PH₃-resistant strain (PH₃-R), and the resistance factors were 22.36 and 4.51, respectively. Compared with their susceptible counterparts, the activities per insect and specific activities of GSTs in DDVP-R and PH₃-R were significantly higher. The apparent Michaelis-Menten constant values (Km) for 1-chloro-2,4-dinitrobenzene (CDNB) were obviously lower in DDVP-R and PH₃-R (i.e. lower Km values, 1.5625 mm for DDVP-R and 0.6230 mm for PH₃-R) when compared with their susceptible counterpart (Km = 3.5520), indicating a higher affinity to the substrate CDNB in resistant strains. In contrast, the catalytic activity of GSTs towards CDNB in the susceptible strain was significantly higher than those in resistant strains. It was noticeable that when reduced glutathione (GSH) was used as substrate, GSTs from resistant strains both indicated a significantly declined affinity. For the catalytic activity of GSTs towards GSH, only the Vmax value in DDVP-R increased significantly compared with that from the susceptible strain, suggesting an overexpression of GST in this resistant strain. The inhibition kinetics of insecticides to GSTs in vitro revealed that dichlorvos and paraoxon possessed excellent inhibition effects on GSTs. The susceptible strain showed higher sensitivity (I50 = 0.9004 mm) to dichlorvos than DDVP-R and PH₃-R (higher I50s, 8.0955 mm for DDVP-R and 9.3346 mm for PH₃-R). As for paraoxon, there was a similar situation. The resistant strains both suggested a higher I50 (1.8735 mm for DDVP-R, and 0.4291 mm for PH₃-R) compared with the susceptible strain (0.2943 mm). These suggested that an elevated detoxification ability of GSTs developed in the resistant strains.
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Link to article at publishers website
Database assignments for author(s): Jin-Jun Wang

Research topic(s) for pests/diseases/weeds:
pesticide resistance of pest

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Liposcelis bostrychophila