The biotransformation of orbencarb (S-2-chlorobenzyl N, N-diethylthiocarbamate) in soils under upland conditions, shoots of soybean plant and rat liver microsomes, was studied to obtain a novel metabolite using [ring-U-¹⁴C]orbencarb. S-2-Chlorobenzyl N-ethyl-N-vinylthiocarbamate in which two hydrogen atoms were removed from an N-ethyl moiety of orbencarb was found to be a novel metabolite in all cases and it was tentatively identified by two-dimensional thin-layer co-chromatography with the authentic compound. A similar type of novel metabolite was isolated from the soil treated with non-radioactive benthiocarb (4-chloro isomer of orbencarb) under upland conditions, and its chemical structure was confirmed as S-4-chlorobenzyl N-ethyl-N-vinylthiocarbamate by comparing it with the synthetic compound in GC retention time and GC-mass spectrum.

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One isomer (A) of tralomethrin [(S)-α-cyano-3-phenoxybenzyl (1′RS)-cis-(1R, 3R)-3-(1, 2, 2, 2-tetrabromoethyl)-2, 2-dimethylcyclopropanecarboxylate] and deltamethrin [(S)-α-cyano-3-phenoxybenzyl (1R, 3R)-3-(2, 2-dibromovinyl)-2, 2-dimethylcyclopropanecarboxylate] labeled with ¹⁴C in the benzylic carbon were applied on or injected into the larvae of tobacco cutworm, Spodoptera litura (F.). On topical application, tralomethrin A was rapidly converted to deltamethrin on the surface and in the body of the larvae. The conversion occurred in the insect body to a larger extent than on the surface. Injection of tralomethrin A led to more rapid formation of deltamethrin than topical application. Formed deltamethrin exceeded tralomethrin A in amount within several minutes after injection. In vitro studies revealed that the conversion was facilitated nonenzymatically by thiols such as glutathione, cysteine and dithiothreitol, but inhibited by N-ethylmaleimide and 1, 2-dibromotetrachloroethane. 1, 1, 2, 2-Tetrabromoethane, 1, 2-dibromoethane and 1, 2-dibromo-1, 2-diphenylethane, however, showed hardly any inhibitory effects on the conversion. There was no significant difference between tralomethrin A and another isomer, tralomethrin B, in the conversion rate to deltamethrin.

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The absorption and distribution of ¹⁴C-altericidins in the cells of Alternaria kikuchiana, a sensitive fungus, were investigated. The absorption of altericidins (A and B) into living and heat-treated mycelia proceeded rapidly, reaching the maximum level within 10min. There was no difference in the rate of absorption between living and heat-treated mycelia. When lipid was removed from the mycelia, the absorption decreased markedly while it does not in the intact mycelia. In both living and heat-treated mycelia, more than 80% of total radioactivity was found in the crude lipid fraction when mycelia were subjected to the fractionation of cell components. The crude lipid fraction, extracted with methanol-chloroform-water from living mycelia, was separated into two fractions, i. e., lipid and lipid-free fractions, and 94% of the radioactivity was detected in the lipid-free fraction. When a sequential enzymatic degradation method was applied to the living mycelia, 50-58% of total radioactivity was found in the fraction solubilized by β-1, 3-glucanase and 20-30% in the residue. On the other hand in the heat-treated mycelia, 26% was detected in each β-1, 3-glucanase and pronase-solubilized fraction and 40% in the residue. These results indicate that the cell wall glucan is closely associated with lipid and that altericidins absorbed in the lipid may partly be released by the degradation of cell wall. The conidia treated with altericidins could never restore their viability even by subsequent washing with water containing one drop of Tween 80per 500ml. Such a finding suggests that altericidins are easily and passively absorbed into lipid that is associated with cell wall glucan and plasma membrane.

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An analytical method of residues of an insecticide bensultap, S, S′-2-dimethylaminotri-methylene di(benzenethiosulfonate), in the potato, corn, grape, tea, cabbage, Chinese cabbage, radish, rice grain, rice straw and soil was established. Bensultap in a blended sample reacted with cysteine in an acidic suspension to give disulfide. The disulfide was converted to nereistoxin by basifying the mixture with an addition of concentrated ammonium hydroxide in the presence of excess cysteine. After extraction and cleanup by partitioning between the solvent, nereistoxin was determined by gas chromatography with FPD. For samples of cabbage, Chinese cabbage and radish, purification by alumina column chromatography was necessary in addition to the solvent partitioning. Recoveries in the fortification tests at a 40-fold level of the detection limit ranged from 76 to 95% and limits of detection from 0.01 to 0.05ppm.

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The photodegradation of an insecticide, dipropyl 4-(methylthio)phenyl phosphate (propaphos), was investigated under xenon lamp irradiation. Propaphos was easily decomposed after 60min irradiation, and the wavelengths for the 50% recovery in methanol solutions after constant irradiation for 60min were 318nm in the 12.5ppm solution, 314nm in the 100ppm solution and 312nm in the 200ppm solution, respectively, and those in water solutions 344nm in the 12.5ppm solution and 339nm in the 100ppm solution, respectively. Oxidation and hydrolysis were the main reactions involved in the photodegradation of propaphos. As the photodegradation products, dipropyl 4-(methylsulfinyl)phenyl phosphate, dipropyl 4-(methylsulfonyl)phenyl phosphate, dipropyl 4-(methoxysulfinyl)phenyl phosphate and dipropyl phenyl phosphate were tentatively identified by gas chromatography-mass spectrometry in the methanol solutions, and dipropyl 4-(methylsulfinyl)phenyl phosphate, dipropyl 4-(methylsulfonyl)-phenyl phosphate, 4-(methylthio)phenol, 4-(methylsulfinyl)phenol, 4-(methylsulfonyl)phenol, 1, 4-benzenediol, 4-hydoxythiophenol and dipropyl phenyl phosphate in the water solutions.

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Three different molinate (S-ethyl perhydroazepine-1-carbothioate)-degrading microbes isolated from soil, Mycobacterium sp. (B-1), Flavobacteriunm sp. (B-2) and Streptomyces sp. (A-1), were investigated on their substrate specificity and induction of degrading activity for molinate and its related compounds. B-1 and A-1 degraded various chemicals of a broad range, while B-2 degraded rather specific chemicals. The development of the degrading activity was presumed to be caused by the induction of the degrading enzymes in two ways depending on the kind of microbes and compounds: 1) Molinate and its related compounds were degraded by the same or individual but similarly regulated enzyme systems. 2) Molinate and the related compounds were degraded by more than two different enzyme systems. In some of the former cases, molinate and the related compounds induced the activity almost to the same extent, but quite differently in others.

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Enantiomers of isoprothiolane sulfoxide (diisopropyl 1-oxo-1, 3-dithiolan-2-ylidenemalonate) were resolved and separately analyzed both by chiral HPLC. The specific rotation was around + and -112° for each antipode. Isoprothiolane (diisopropyl 1, 3-dithiolan-2-ylidenemalonate) was easily oxidized by a rat liver 9000g supernatant to produce its racemic sulfoxide, in which NADPH was an effective cofactor but NADH was not. The liver microsomes, however, preferentially formed its (+)-isomer in an enantiomeric excess of 38-43%. Phenobarbital (PB) increased the sulfoxidation activity of microsomes by 400% without any marked change in the enantiomeric excess. 3-Methylcholanthrene (3-MC) induced the microsomal activity more enantiomerically, forming isoprothiolane (+)-sulfoxide in an enantiomeric excess of 83%. Thus, 3-MC-induced microsomal enzyme(s) oxidized isoprothiolane to its (+)-sulfoxide more stereoselectively than PB-induced microsomal enzyme(s). The sulfoxidation of isoprothiolane by rice plants proceeded too slowly for the metabolite chirality to be analyzed. Both isoprothiolane (+)- and (-)-sulfoxides underwent rapid racemization by rat liver cytosol (105, 000g supernatant) or rice plants, accompanied by the reduction to isoprothiolane.

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The thirty-four N-methyl-2′-methoxy (substituted) benzanilides were synthesized and their preventive activities against rice blast were studied by the pot test. The substitution at the para-position of benzoyl moiety varied the activity to various extents. The inhibitory activity of N-methyl-2′-methoxy-4-substituted benzanilides on the penetration of infection pegs from appressoria of Pyricularia oryzae were also measured by using cellophane film as a model of plant cell walls and the structure-activity relationships were analyzed using the physicochemical parameters and regression analysis. The inhibitory activities were related to the bulkiness and electronic effect of the substituents and parabolically to the hydrophobicity of the molecules.

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A procedure for high performance liquid chromatographic determination of total bromine in crops was examined. Sample crops were dried and ashed. Bromine in the ashed residue was extracted with water. The extract was cleaned up successively by using barium hydroxide solution and disposable cation exchange column, and then bromide was determined by high performance liquid chromatography (HPLC) with UV detector (245nm). The HPLC column was MCI GEL SCA 02 and the eluent 5×10^-4M potassium biphthalate. The limits of detection were 0.7-3ppm and the recoveries from fortified crops (fortification: 14-67ppm of bromide) 73-91%. The method was proved to be simple and selective for the determination of total bromine in crops.

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The mode of inheritance of resistance to pyrethroids in the housefly (Musca domestica L.) was investigated using electrophysiological techniques, following permethrin and cypermethrin application to the exposed thoracic ganglia of the susceptible SRS strain, pyrethroid-resistant 228e₂b strain and their F₁ hybrids (S_??_×R_??_ and R_??_×S_??_). The nervous system of the resistant houseflies was far less sensitive than that of the susceptible and hybrid houseflies. The hybrids exhibited an incompletely recessive decreased nerve sensitivity, in agreement with the toxicological results. Dominance values in each of reciprocal crosses were identical in toxicological and nerve sensitivity. Therefore, it is concluded that nerve insensitivity plays a major role in resistance to pyrethroids in the resistant strain and that this resistance is inherited as an incompletely recessive genetic factor and is not related to either sex-linkage or cytoplasmic influence.

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Foliar wettability of rice plants for aqueous solutions of nonionic surfactants was studied and compared with that of cabbage and soybean plants. Rice leaves were found highly water-repellent having large contact angles over 130° and their wettability was affected by the addition of surfactants most among all the plants examined. The effectiveness of surfactants in enhancing retention of dye solutions in leaves was related to their effectiveness in decreasing surface tension. The surfactants gave the highest retention at their optimum concentrations, which appeared to correspond to their critical micelle concentrations; POE lauryl ether at 0.01%, POE nonylphenyl ether at 0.1% and POE sorbitan monolaurate at 0.5 to 1.0%w/v. It is therefore suggested that rice plants belong to the species with lower wettability and that they need wetting agents to improve foliar wettability.

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[Phenyl ring-U-¹⁴C] buprofezin, 2-tert-butylimino-3-isopropyl-5-phenyl-perhydro-1, 3, 5-thiadiazin-4-one, gradually decomposed in soils under flooded and upland conditions, with the half lives of 104 and 80 days, respectively. After 150 days, five degradation products were identified by thin-layer cochromatography: 2-tert-butylimino-5-(4-hydroxyphenyl)-3-isopropyl-perhydro-1, 3, 5-thiadiadin-4-one, 3-isopropyl-5-phenyl-perhydro-1, 3, 5-thiadiazin-2, 4-dione, 1-tert-butyl-3-isopropyl-5-phenyl-biuret, 1-isopropyl-3-phenylurea and phenylurea. As minor products, 2-tert-butylimino-5-phenyl-perhydro-1, 3, 5-thiadiazin-4-one or buprofezin sulfoxide were found in the flooded or the upland soil. [¹⁴C]Carbon dioxide and bound ¹⁴C residue accounted for 23-24% and 13-21% of the applied radioactivity, respectively. The degradation of buprofezin remarkably delayed in sterile soils. Since neither formation of ¹⁴CO₂ nor ring hydroxylation was observed in the sterile soils, buprofezin seems to have undergone complete mineralization in the soils under both flooded and upland conditions through biological transformation by soil microorganisms.

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N-(1-Methyl-1-phenylethyl)phenylacetamides exhibited strong growth-inhibiting activity against bulrush, Scirpus juncoides, and barnyard grass, Echinochloa crus-galli, in the vial tests. The phenylacetyl group was essential for the high activity against S. juncoides. Structure-activity relationships of N-(1-methyl-1-phenylethyl)phenylacetamides having various benzene ring substituents in the acid and amine moieties were analyzed with substituent parameters and regression techniques. The variation in the activity of 83 compounds was related parabolically with the hydrophobicity of the substituents. The steric factor was also important for the activity: it increased with a decrease in length of the 4-substituents in the acid moiety. Electron-withdrawing effect of the substituents at the 3- or 4-position in the amine moiety increased the activity, too. A similar equation was obtained against E. crus-galli. The growth-inhibiting activity was highly correlated with the herbicidal activity in the pot tests.

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The photodegradation of 3, 3′-diindolylmethane (DIM), which has the antifungal activity against Xanthomonas campestris pv. oryzae, Cochliobolus miyabeanus and Pyricularia oryzae, was investigated under xenon lamp irradiation. The maximal degradation of DIM in 12.5ppm methanol solution was observed in the UV range of 280nm to 290nm. The range of wavelengths for the maximal degradation shifted to longer wavelengths as DIM concentration in methanol solution increased. For example, the range shifted from 280-290nm in 12.5ppm solution to 320-330nm in 200ppm solution. Nine compounds were detected as the photo-degradation products of DIM and their structures were tentatively determined by gas chromatography-mass spectrometry as 3-formylindole, indole, 2-aminophenol, indole-2, 3-dione, methyl 2-aminobenzoate, indole-2-one, 3-methoxymethylindole, methyl 2-ethylaminobenzoate, and 1-(2-dimethylaminophenyl)ethanone, respectively.

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