Carboxylesterase activity of the cotton aphid (Aphis gossypii GLOVER), using naphth-1-yl acetate as a substrate, varied greatly among the clones and was closely correlated to the degree of ...organophosphorus insecticide resistance. Approximately 90% of the carboxylesterase activity was distributed in soluble fraction. The soluble fraction of both the susceptible and the resistant clones exhibited limited hydrolytic activity against fenitroxon, whereas that of the resistant clones showed significant sequestering activity proportional to carboxylesterase activity. Both the carboxylesterase activity and the fenitroxon sequestering activity were markedly inhibited by 2-phenoxy-4H-1, 3, 2-benzodioxaphosphorin 2-oxide (K-2) but not by S, S, S-tributyl phosphorotrithioate (DEF) and iprobenfos (IBP, Kitazin P(R)). Among these three esterase inhibitors, only K-2 showed synergistic action on the toxicity of fenitrothion. Furthermore, the fenitroxon sequestering activity was markedly reduced by coexistence with an excess amount of naphth-1-yl acetate. Based on these results, it was concluded that the carboxylesterase of A. gossypii had a role in fenitrothion resistance as a sequestering protein.
Mating-choice and host preference tests were carried out in the rice (Oryza sativa)-feeding (RF) and water-oat (Zizania latifolia)-feeding (WOF) types of Chilo suppressalis W. The mating-choice tests ...revealed that matings occurred not only with in the same type, but also between the two types. However, the peaks of mating-time of females were different, i.e., that of the RF type was 3 hr earlier than that of the WOF type. The host preference tests revealed that females of both types have a tendency to select their own host for oviposition.
The insecticides susceptibility of adults of the water strider, Gerris latiabdominis, was studied. The water strider is quite susceptible to insecticides and the LD50 values of organophosphates, ...carbamates, pyrethroids, nereistoxins, and neonicotinoids ranged from 0.24 to 31.6μg/g. The LD50 values for fenitrothion, BPMC and PHC were low compared to those for several Hemipteran insect pests of rice paddy.
Many of existing factories and warehouses have problems in indoor thermal environment. Thermal simulation is an effective way to resolve such problems. In many cases, however, air change rate and ...heating value in buildings, which should be critical parameters, are unclear. This paper discusses the methodology for measuring indoor temperature and thereby indirectly calculating air change rate and heating value. In this methodology for calculating indoor temperature, appropriate thermal equilibrium formulas are created, and measured temperatures are put into these formulas by time to calculate unknown quantities. This methodology is presented with numerical models. Simulation results were found to agree well with the results actually measured in a factory, which enabled us to confirm the effectiveness of this methodology.
IMP dehydrogenase (EC 1.1.1.205), the rate-limiting enzyme of de novo GTP biosynthesis, is a promising target in antileukemic chemotherapy. We have isolated two distinct cDNA clones (types I and II) ...encoding IMP dehydrogenase from a human spleen cDNA library. Both clones encode closely related proteins of 514 residues showing 84% sequence identity. Northern hybridization analyses of poly(A)+ RNA from human normal leukocytes and human ovarian tumors demonstrated a striking contrast in mRNA expression in that type I mRNA is the main species in normal leukocytes and type II predominates over type I in the tumor. This is the first report suggesting the existence of two distinct types of human IMP dehydrogenase molecular species which may have different sensitivities to the drugs targeted against IMP dehydrogenase.
Susceptibility to fenitrothion, carboxylesterase activity (substrate:α-naphthyl acetate) and carboxylesterase isozyme pattern in the rice stem borer, Chilo suppressalis Walker, collected from ...Yamagata Prefecture were studied. Among four strains tested, three strains showed high levels of fenitrothion resistance, and there was a positive relationship between the resistance and carboxylesterase activity. Isoelectrofocusing revealed that a single carboxylesterase isozyme (pI=5.2) was preferencially observed in the three resistant strains.
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.
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