TY - JOUR
T1 - Carboxylesterase of the Rice Stem Borer, Chilo suppressalis Walker (Lepidoptera
T2 - Pyralidae), Responsible for Fenitrothion Resistance as a Sequestering Protein
AU - Konno, Yasuhiko
N1 - Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 1996
Y1 - 1996
N2 - Carboxylesterase of the rice stem borer, Chilo suppressalis Walker, was studied, whether or not the enzyme has a sequestering activity to fenitroxon. Both the carboxylesterase activity (substrate: α-naphthyl acetate) and the fenitroxon sequestering activity of C. suppressalis closely correlated with the degree of resistance to fenitrothion. The fenitroxon sequestering activity was localized mainly in the midgut, and the Scatchard analysis showed that the KD and Bmax values of organophosphate (OP)-resistant strain were 0.65 µm and 1.42 nmol/mg protein, respectively, and those of OP-susceptible strain were 0.66 µm and 0.20 nmol/mg protein, respectively. The carboxylesterase isozyme patterns separated by IEF were clearly different between the two strains, i.e., the OP-resistant strain has only one highly active isozyme (pI = 5.2), whereas the isozyme (pI = 5.2) was scarcely in the OP-susceptible strain. In the OP-resistant strain, the carboxylesterase activity of the isozyme (pI = 5.2) evaluated by a red coloration on IEF gel was significantly inhibited by the preincubation with fenitroxon. Furthermore, the fenitroxon sequestering activity was markedly reduced by coexistence with an excess amount of α-naphthyl acetate. Based on these results, it was suggested that the carboxylesterase of C. suppressalis has a role in fenitrothion resistance as a sequestering protein.
AB - Carboxylesterase of the rice stem borer, Chilo suppressalis Walker, was studied, whether or not the enzyme has a sequestering activity to fenitroxon. Both the carboxylesterase activity (substrate: α-naphthyl acetate) and the fenitroxon sequestering activity of C. suppressalis closely correlated with the degree of resistance to fenitrothion. The fenitroxon sequestering activity was localized mainly in the midgut, and the Scatchard analysis showed that the KD and Bmax values of organophosphate (OP)-resistant strain were 0.65 µm and 1.42 nmol/mg protein, respectively, and those of OP-susceptible strain were 0.66 µm and 0.20 nmol/mg protein, respectively. The carboxylesterase isozyme patterns separated by IEF were clearly different between the two strains, i.e., the OP-resistant strain has only one highly active isozyme (pI = 5.2), whereas the isozyme (pI = 5.2) was scarcely in the OP-susceptible strain. In the OP-resistant strain, the carboxylesterase activity of the isozyme (pI = 5.2) evaluated by a red coloration on IEF gel was significantly inhibited by the preincubation with fenitroxon. Furthermore, the fenitroxon sequestering activity was markedly reduced by coexistence with an excess amount of α-naphthyl acetate. Based on these results, it was suggested that the carboxylesterase of C. suppressalis has a role in fenitrothion resistance as a sequestering protein.
UR - http://www.scopus.com/inward/record.url?scp=0030413981&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0030413981&partnerID=8YFLogxK
U2 - 10.1584/jpestics.21.425
DO - 10.1584/jpestics.21.425
M3 - Article
AN - SCOPUS:0030413981
VL - 21
SP - 425
EP - 429
JO - Journal of Pesticide Sciences
JF - Journal of Pesticide Sciences
SN - 1348-589X
IS - 4
ER -