Tsagkarakou_2002_Insect.Biochem.Mol.Biol_32_417

Reference

Title : Mechanisms of resistance to organophosphates in Tetranychus urticae (Acari: Tetranychidae) from Greece - Tsagkarakou_2002_Insect.Biochem.Mol.Biol_32_417
Author(s) : Tsagkarakou A , Pasteur N , Cuany A , Chevillon C , Navajas M
Ref : Insect Biochemistry & Molecular Biology , 32 :417 , 2002
Abstract :

We investigated the mechanisms conferring resistance to methyl-parathion (44-fold) and to methomyl (8-fold) in Tetranychus urticae from Greece by studying the effect of synergists on the resistance and the kinetic characteristics of various enzymes in a resistant strain (RLAB) and a susceptible reference strain (SAMB). It is shown that S,S,S-tributyl phosphorotrithioate, a synergist that inhibits esterases and glutathione S-transferases, and piperonyl butoxide, a synergist that inhibits cytochrome P450 mediated monooxygenases, did not affect the level of methyl-parathion or methomyl resistance in RLAB and that resistance ratios to both insecticides did not change significantly in the presence of either synergist. Isoelectric focusing of esterase allozymes on single mites revealed no differences in staining intensity and glutathione S-transferase activity was not significantly different in the two strains. The activity of two cytochrome P450 monooxygenase groups was compared. No significant difference of 7-ethoxyresorufin-O-diethylase activity was observed between strains that were two-fold higher in RLAB than in SAMB. The kinetic characteristics of acetylcholinesterase, the target enzyme of organophosphates and carbamates, revealed that acetylcholinesterase in RLAB was less sensitive to inhibition by paraoxon and methomyl in comparison with SAMB. I(50), the inhibitor concentration inducing 50% decrease of acetylcholinesterase activity was greater (119- and 50-fold with paraoxon and methomyl, respectively) and the bimolecular constant k(i) was lower (39- and 47-fold with paraoxon and methomyl, respectively) in RLAB compared to SAMB.

PubMedSearch : Tsagkarakou_2002_Insect.Biochem.Mol.Biol_32_417
PubMedID: 11886776

Related information

Inhibitor Tribufos

Citations formats

Tsagkarakou A, Pasteur N, Cuany A, Chevillon C, Navajas M (2002)
Mechanisms of resistance to organophosphates in Tetranychus urticae (Acari: Tetranychidae) from Greece
Insect Biochemistry & Molecular Biology 32 :417

Tsagkarakou A, Pasteur N, Cuany A, Chevillon C, Navajas M (2002)
Insect Biochemistry & Molecular Biology 32 :417