It was confirmed that the enantiomers in racemic S-2571 (O-ethyl O-2-nitro-5-methylphenyl N-isopropyl phosphoramidothioate) were stereoselectively metabolized by rabbit liver microsomal mixed function oxidase to give dextrorotatory products of parent compound, the oxon analog and derivatives hydroxylated at the 5-methyl group. The corresponding products obtained from (+)-S-2571 were all dextrorotatory and those from (-)-S-2571 were levorotatory. Oxidation of the optical isomers of S-2571 to the corresponding oxon analogs by UV light was also stereospecific. Comparison with the results from m-chloroperoxybenzoic acid oxidation suggests that oxidation of P=S to P=O by the mixed function oxidase and UV light may proceed with retention of configuration at phosphorus.

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Volatilization of benthiocarb herbicide (S-4-chlorobenzyl N, N-dietylthiocarbamate) from its aqueous solution and from soil was studied in the laboratory. Exposure of the aqueous solution of ¹⁴C-benthiocarb to sunlight resulted in a remarkable decrease in radioactivity, which was approximately proportional to the decrease in the amount of water by evaporation. The presence of soil in the aqueous solution, however, largely depressed the radioactivity loss. Volatilization of benthiocarb from unflooded soil was much less than from flooded soil. More than half of the radioactive substances volatilized from the aqueous solution exposed to the sun was composed of parent benthiocarb itself, while the rest consisted of volatile photo-degradation products such as 4-chlorobenzaldehyde, formed under the experimental conditions used in this study.

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Sixty compounds structurally related to methyleugenol, which is believed to be one of the most powerful attractant for male oriental fruit fly (Dacus dorsalis Hendel) were tested for their attractiveness against this insect with a specially designed olfactometer. No definite correlation between the structure and activity was found, but some tendency was observed. Methylisoeugenol, veratric acid, methyleugenol and eugenol were the most effective attractants among these compounds tested. A part of these synthetic compounds were also tested against melon fly (Dacus cucurbitae Coquillett). None of the chemicals tested was found to be significantly attractive for this insect.

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The antifungal activity of polyoxin A against Alternaria kikuchiana disappeared in the presence of glycylglycine, glycyl-L-alanine, glycyl-L-valine and glycyl-L-leucine at a concentration 500 times higher than that of the antibiotic, while some amino acids and nucleosides showed no effect. Dipeptides, amino acids and nucleosides did not antagonize to the inhibition of isolated chitin synthetase by polyoxin A. Effects of these dipeptides on the uptake of polyoxin A into the cell and on the inhibition of chitin biosynthesis by the antibiotic were investigated by incubating the washed mycelia of A. kikuchiana with ³H-polyoxin A and ¹⁴C-glucosamine in the presence or absence of dipeptides. It was found that the dipeptides at a concentration of 10mM reduced 70-80% of the uptake of polyoxin A, which was initially added to the incubation mixture at a concentration of 19μM, and at the same time they recovered 40-80% of the inhibition of ¹⁴C-glucosamine incorporation into chitin. Amino acids tested showed a slight antagonistic effect and nucleosides did not affect on the antibiotic uptake and the inhibition of chitin biosynthesis. Lineweaver and Burk plot showed that the inhibition of ¹⁴C-polyoxin A uptake by glycylglycine was evidently a competitive type. The uptake of ¹⁴C-glycylglycine by the washed mycelia decreased with the increasing order of polyoxin-resistance in various strains of A. kikuchiana. This result showed a good agreement with that obtained in ¹⁴C-polyoxin A uptake by the same strains. On the other hand, the uptakes of ¹⁴C-amino acid mixture, ¹⁴C-uracil and ¹⁴C-glucosamine were independent of the polyoxin-sensitivity. The uptakes of ¹⁴C-polyoxin A and ¹⁴C-glycylglycine by the sensitive strain were equally influenced by EDTA, sodium lauryl sulphate, metabolic inhibitors, metal ions and pH.

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In vitro metabolism of malathion was studied in malathion resistant (Sapporo, Moiwa and 15-D) and susceptible (Takatsuki, Yakumo and Hokota) strains of houseflies. Resistant ratios of Sappro, Moiwa and 15-D strains to a susceptible strain Takatsuki were 57.4, 83.6 and 113.3, respectively. Malathion degrading carboxylesterase activity was 30 to 39 times higher in resistant strains than in Takatsuki strain. Malaoxon degrading activity was also about 10 times higher in the resistant strains than in Takatsuki strain. Malathion degrading carboxylesterase activity was highest in the microsomal fraction of Sapporo and Moiwa strains, in the supernatant fraction of 15-D strain. The main in vitro metabolism products were malathion monocarboxylic acid and malathion dicarboxylic acid. From these results enhanced both malathion degrading carboxylesterase activity and malaoxon degrading activity were concluded to be main factors of malathion resistance mechanism. In 15-D strain, there appears to be another mechanism involving an enhanced glutathione S-transferase activity.

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¹⁴C-promecarb was applied to the top one inch of soil in metal pails, and corn seeds were planted. Analysis of corn plants at various intervals after planting indicated that the radioactive material was absorbed by the roots and was present in the stems and leaves. The compound was metabolized to isothymol and to other unidentified organosoluble metabolites during the 90-day test period.

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Sodium hydrogencarbonate showed a remarkable protective effect on the decay of citrus fruit by various diseases during storage. The effect of this compound was tested by using citrus fruit which was artificially wounded with needless. The following results were obtained from a series of tests. 1. The occurrence of common green mold on wounded fruit was inhibited by the treatment with solutions of phosphate buffer adjusted to pH 7 and 8, but the solution of lactate buffer with pH3 was not effective. 2. When fruit was dipped into sodium hydrogencarbonate solution before injury, this treatment gave an excellent protection against development of common green mold. 3. When fruit with injured peel was dipped into the solution of chemicals, the developments of common green mold and contact blue mold were prevented 100per cent and 70per cent respectively. 4. When fruit was dipped into sodium hydrogencarbonate solution after inoculating P. digitatum and incubating for 24hr, the number of decayed fruit was decreased. 5. After being dipped into sodium hydrogencarbonate solution, when fruit was stored from January to the following February the development of common green mold was prevented 98per cent and other storage diseases such as anthracnose, gray mold etc. were also suppressed remarkably.

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Disappearance of dicofol, 2, 2, 2-trichloro-1, 1-bis (p-chlorophenyl) ethanol, and chlorthiamid, 2, 6-dichlorothiobenzamide, were investigated under various test conditions to estimate the evaporation of the chemicals from soil. The chemicals were mixed with soil or added on the surface of the soil in glass bottles. The mouthes of a part of bottles were closed with aluminium foil and those of other bottles were kept open. The bottles containing the soil were stored in an incubator or in a room or outdoors. The chemicals in the soil were assayed periodically by gaschromatography. As dicofol disappeared very slowly and the rates of losses from soil were almost same in every conditions tested, the evaporation of this compound from soil seemed to be little, while some of dicofol evaporated from the water suspension or thin film of the chemical under same condition. Only a little of chlorthiamid disappeared from the soil stored in closed vessels, while relatively rapid loss by evaporation was observed when the soil was stored in open bottles. The soil-persistency test of pesticide is recommended to be done by two methods, the field test and the test using the soil stored in closed vessels. Results of the field test were sometimes disturbed by large variation of spray deposits on field soil. In the test with closed vessel, though the test conditions are controlled easily and the error is relatively small, losses of chemicals by evaporation, photolysis or leaching which are not negligible under field conditions are not measured. So when the results of the tests by two methods did not well agreed, the other tests to estimate the losses of chemicals from soil by the routs mentioned above should be done.

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A highly specific mass fragmentographic method for quantitative determination of bis (2-chloro-1-methylethyl) ether [DCIP] in rat tissues was developed. DCIP in the white adipose tissue, liver, kidney and blood of rat was steam distilled and trapped in toluene. The toluene solution was dried over anhydrous sodium sulfate and injected directly into a gaschromatographmass spectrometer (GC-MS), equipped with a multiple ion detector. DCIP was determined by comparing the peak heights of two ion fragments (m/e 121 and 123) with the corresponding peak heights of known amounts of standards. The experimental conditions of GC-MS were as follows: GC-column, 2.0m×3.0mm (i. d.) glass column, packed with 2% OV-17 on Gaschrom Q; electron energy, 70eV; flash heater temp., 200°C; column oven temp., 120°C; separater temp., 240°C; ion source temp., 270°C; and helium flow rate, 30ml/min. The linearity and reproducibility of the responce of the mass spectrometer detector was demonstrated in 0.2-4.0ng range. Any interference on the mass fragmentograms was not observed in the analysis of the rat tissues. Using 10g of the sample, the method was sensitive to 0.05ppm and the recoveries of DCIP averaged 87±16%.

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