The insecticide susceptibility of the Fall Webworm, Hyphantria cunea and its parasitoid fly, Exorista japonica, was studied. Larvae of H. cunea were hardly susceptible to organophosphorus ...insecticides, such as fenitrothion (LD50=>100μg/larva) and isoxathion (LD50=54μg/larva). However, adults of H. cunea were quite susceptible to fenitrothion (LD50=1.4μg/male and 2.2μg/female). Adults of E. japonica emerging from pupa of H. cunea were very susceptible to fenitrothion (LD50=0.082μg/adult). The results suggest that a judicious choice of insecticide is necessary to control H. cunea, if E. japonica is used as a biological control agent, too.
The discovery of isozymes (types I and II) of IMP dehydrogenase (IMPDH; EC 1.1.1.205), the rate-limiting enzyme of de novo GTP biosynthesis, has attracted attention as a possible novel approach to ...cancer diagnosis and selective tumor cell chemotherapy. To elucidate differences in expression and regulation of the two IMPDH isozymes, we examined the steady-state levels of these mRNAs in various types of leukemic cells from patients. Northern blot analysis revealed that type II IMPDH was more active transcriptionally (1.5- to 5.1-fold) in all the leukemic cells examined than in normal lymphocytes, whereas type I expression was similar. The increased expression of type II mRNA in leukemic cells was closely linked with the increase in total IMPDH activity (r = 0.92). When leukemic cells from a patient with chronic granulocytic leukemia in blast crisis were separated into blast-rich and mature leukocyte-rich fractions, the expression of type II mRNA correlated positively with the population of immature leukemic cells, whereas type I expression was unchanged. Treatment of leukemic blasts with 12-O-tetradecanoyl-phorbol-13-acetate for 5 days resulted in a 90% decrease in the expression of type II mRNA with macrophage-like differentiation, while the expression of type I mRNA was relatively stable. These observations suggest that expression of type II IMPDH is stringently linked with immature characteristics of leukemic cells; thus, it should be a selective target for antileukemic chemotherapy.
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 0.65μM and 1.42nmol/mg protein, respectively, and those of OP-susceptible strain were 0.66μM and 0.20nmol/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.
The species composition of anthophilous Diptera and Hymenoptera on three alpine flowers was investigated at an altitude of 1,950-m on Mt. Hakuundake in the Daisetsu Mountains, Hokkaido, Japan. A ...total of 317 individuals from 35 species of nine families was collected. The most abundant insect family was Syrphidae (64.4% of individuals), followed by Anthomyiidae (16.4%) and Halictidae (6.0%). On Sorbus matsumurana (Rosaceae), 1 50 individuals from 27 species were collected; the most abundant was Syrphidae, followed by Empididae and Tenthredinidae. On Weigela middendorffiana (Caprifoliaceae), 103 individuals from 22 species were collected; the most abundant was Syrphidae, followed by Halictidae and Apidae. On Trollius riederianus (Ranunculaceae), 64 individuals from 8 species were collected; the most abundant was Anthomyiidae, followed by Syrphidae and Apidae. Species diversity (1/D) was the highest on W. middendorffiana (9.7) and the lowest on T. riederianus (3.9). The index of similarity, QS, was largest for the combination of S. matsumurana and W middendorffiana (0.71), and smallest for S, matsumurana and T riederianus (0.28).
An improved artificial diet without dry cruciferous leaf powder for the cabbage small white, Pieris rapae, was investigated. The diet consisted of kidney bean, chlorella powder, dried cowpea leaf ...powder, casein, dry yeast powder, cholin chroride, inositol, ascorbic acid, cholesterol, lenolenic acid, sodium poropionate, citric acid monohydrate, cellulose powder, agar and water. It was consumed readily by larvae with more than 70% of the larvae developing into adults.
Sensitivity of acetylcholinesterase (AChE) to inhibitors and metabolism of ring and methoxy-14C labelled fenitrothion and methoxy-14C labelled fenitroxon were examined in the organophosphate ...(OP)-resistant and -susceptible strains of the bulb mite Rhizoglyphus robini. The experimental evidence obtained from the in vivo and in vitro tests revealed that reduced cuticular penetration rates of fenitrothion and increased detoxification of fenitroxon were responsible for fenitrothion resistance in OP-resistant strain. But there were no inter-strain differences in sensitivity of AChE to inhibitors, and also in activities of mixed function oxidases, glutathion-S-transferase to fenitrothion and binding protein in fenitrothion detoxification.
The inheritance of fenitrothion resistance (22-fold) and pirimiphos-methyl resistance (500-fold) was studied in the OP-resistant Hata-f strain of the rice stem borer, Chilo suppressalis. The ...resistance was found to be incompletely recessive, and no extranuclear effects were found. The degree of dominance (D) for fenitrothion was -0.31 to -0.37 and that for pirimiphosmethyl was -0.14 to -0.21. Observed mortalities for the backcross progenies F1(Hata-f〓×S〓)〓×Hata-f〓 were almost identical with the expected on the basis of a single major gene inheritance. However, the observed mortalities at high dosages were significantly higher than expected, indicating that minor modifying genes might be involved in the resistance. The inheritance of the two fenitroxon detoxication activities (binding protein and hydrolysis) were also incompletely recessive.
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