Butachlor [2-chloro-2′, 6′-diethyl-N-(butoxymethyl)acetanilide] was applied at the recommended rate, and at ten and fifty times the recommended rate to samples of silty clay loam and then compared with untreated samples incubated at 15°C or 30°C under waterlogged conditions. The effects of the herbicide on ammonification and nitrification were studied by adding 100ppm NH₂-N as CO(NH₂)₂ or NH₄-N as (NH₄)₂SO₄ respectively, at pH 6.8 by the addition of CaCO₃ to the soil. Butachlor at all doses inhibited the rate of ammonification and stimulated the rate of nitrification slightly at 30°C when pH was adjusted from the original 4.9 to 6.8. At ten and fifty times the recommended rate, butachlor delayed the maximum rate of ammonification of CO(NH₂)₂, and at the fifty fold dose inhibited the nitrification of (NH₄)₂SO₄ at 30°C when pH was not adjusted. The effects of butachlor on ammonification and nitrification were not significant compared to those of the control at 15°C. One of the major metabolites of butachlor by soil microbes, 2-chloro-2′, 6′-diethylacetanilide, delayed the rate of utilization of NH₄-N, and inhibited NO₂^- oxidation at 1, 000ppm concentration. Butachlor mixed with diphenyl ether type herbicides, nitrofen (2, 4-dichlorophenyl 4′-nitrophenyl ether), chloronitrofen (2, 4, 6-trichlorophenyl 4′-nitrophenyl ether and chlomethoxynil (2, 4-dichlorophenyl 4′-nitro-3′-methoxyphenyl ether) at either normal or ten fold the recommended rate, did not significantly affect the rate of ammonification and nitrification. Cation exchange capacity of the soil was not affected by the application of butachlor after incubation for 7 weeks. Butachlor applied at the normal rate stimulated soil respiration in the initial stage, but at ten and fifty times the recommended rate, inhibitory phenomena were observed. The inhibitory effects seemed to be transitory and disappeared rapidly. Application of butachlor at all rates increased the population of fungi, actinomycetes and bacteria compared to those of the control after incubation for one week. The higher doses of butachlor caused the population of soil microbes to be greater than those of the control up to 4 weeks after incubation.

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The plant growth inhibitory activity of some 7-(β-D-ribofuranosyl)pyrrolo[2, 3-d]-pyrimidines, analogs of the antibiotic tubercidin, was conspicuous through three bioassay systems used in this study, i. e. pre-emergence, foliar treatment and submerged tests. Deribosylated, base analogs of some representatives were, however, shown to be weakly active, implying that the 7-ribosyl moiety plays a role in enhancing activity. On the other hand, some of 4-substitutedamino-pyrrolo[2, 3-d]pyrimidines were as active in the pre-emergence test as the corresponding nucleoside derivatives which are known as anticytokinins in the tobacco callus system. Other kinds of anticytokinins with the pyrrolo[2, 3-d]pyrimidine structure exhibited, however, weak plant growth inhibitory activity, showing that anticytokinin nature in the tobacco callus test is not necessarily in parallel with activities in other test systems like those used in this study.

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Effects of maleic hydrazide (MH) on cigarette smoke inhalation toxicity were studied with male Syrian golden hamsters. The hamsters were divided into 5 groups consisting of 10 animals each. Three of the groups were exposed to smoke from reference cigarettes, cigarettes containing 1% sodium salt of MH (MH-Na), and cigarettes containing 1% diethanolamine salt of MH (MH-DE), respectively, twice a day for 8 minutes, 5 days a week, for 26 weeks in a Hamburg II type smoking machine. The other two groups were served as sham-smoked and cage-held controls. Body weight and food consumption were measured weekly during the testing period. Hematological and blood biochemical analyses, organ weight measurements, and gross and histopathological observations were performed on all the hamsters at the termination. Decreased body weight gains, lower food efficiencies, and higher blood glucose levels were observed in all the smoke-exposed groups. These changes were most evident in the group exposed to smoke from cigarettes with MH-DE, as they exhibited from mild to significant differences from other smoke-exposed groups. This group also showed a significant decrease in plasma protein and blood urea nitrogen levels as compared with the sham-smoked control. On the other hand, addition of MH-Na to cigarettes resulted in no significant differences in any result from the group exposed to the reference cigarette smoke. Histopathological examination revealed that cigarette smoke exposure to the hamsters enhanced alveolar macrophage mobilization and induced epithelial alterations in the respiratory tracts, although there were no significant differences in the incidence and severity of the lesions among the three smoke-exposed groups. It is suggested that MH may have a mild promoting effect on the smoke inhalation toxicity to the hamster in the form of its diethanolamine salt, but not sodium salt.

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The relationships were observed among pycnospore germination rate of Diaporthe citri, concentration of basic copper sulfate, Cu²⁺ ion concentration and pH. In the case of basic copper sulfate, pycnospore germination rate was about 100% at less than 1ppm. It decreased according to the increase in concentration of basic copper sulfate and attained to minimum level at more than 50ppm. In the case of Z-Bordeaux (basic copper sulfate 58%, basic zinc sulfate 15%, basic magnesium carbonate 6%), pycnospore germination rate was about 100% at less than 1ppm of basic copper sulfate. Germination rate decreased at the concentration of 1 to 10ppm, increased at 10 to 50ppm and decreased again at more than 50ppm. Pycnospore germination was completely inhibited at more than 500ppm. At pH 5-6, pycnospore germination rate was about 100% but it gradually decreased with the increase of pH. At pH 8, it was about 35%. Pycnospore germination rate depended upon the Cu²⁺ ion concentration at constant pH (within the range of pH 5-8). Cu²⁺ ion was more eluted at low pH than at high pH under the same concentrations of basic copper sulfate. In the case of Z-Bordeaux, the pycnospore germination was not inhibited so much at the concentration ranging from 10 to 50ppm, because Cu²⁺ ion was less eluted on account of high pH (higher than 7). From 50 to 500ppm, it was further inhibited as pH became 7.5-9.0. Cu²⁺ ion concentration for 50% inhibition of pycnospore germination at pH 6 was about 4.2×10^-5M.

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Most of the pesticides used in Shiga Prefecture were translocated into Lake Biwa (the largest lake in Japan) by various environmental passways. The chlorinated pesticides (BHC and DDT) had been detected from many environmental samples in this lake. In this study, the concentrations of pesticides (BHC, DDT) and herbicide (CNP) residues in isaza (Chaenogobius isaza TANAKA), a small goby fish inhabiting at the northern part of this lake, were determined by gas-chromatography. In all samples collected from 1966 to 1976, BHC (α, β, γ, δ-isomer), DDT and its derivatives (DDE and DDD) and CNP were detected. The highest concentration found in isaza was 2.09ppm as a total BHC (1970), 0.89ppm as a total DDT (1967), 0.11ppm as CNP (1976). Although the use of BHC and DDT were stopped in 1971, the concentration of these pesticides in isaza don't show much decrease, and the concentration of CNP used now is increasing annually. The ratios of β-isomer to total BHC and of DDE to total DDT were annually increasing.

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Distribution of pentachlorophenol (PCP) among soil layers and its long-term effect on the number of aerobic bacteria were surveyed in water-logged soil in pots in a greenhouse. The soil collected from the plow-layer of paddy-fields No. 9 and No. 10 located at Kashimadai Experimental Farm of our Institute was submerged in 1/2, 000 a pots. Powder of PCP (free phenol) was applied to the surface water at a recommended rate (2.67g/m², Plot RR) and at 100 times the recommended rate (267g/m², Plot 100 RR). Water without application was designated as control. PCP accumulated markedly in the oxidative-layer of the soil. After about one month, PCP was detected even in the lower part of the reductive-layer (15-20cm depth). In the upper part of the reductive-layer (0-5cm depth after removing the oxidative-layer), the accumulation and following decrease of PCP were observed clearly. The lowering of redox-potential with time was repressed markedly in Plot 100 RR, nor was there a change in the soil pH with the application of PCP, although the increase in surface-water pH was repressed. The soil became compact due to the application of PCP. The numbers of plants, animals and algae visible to the naked eye decreased markedly immediately after PCP application. In about one month, however, their numbers started to increase, and after about three months the flora was reestablished, although some kinds of worms could not be observed in Plot RR. In Plot 100 RR, none of plants, animals or algae were observed throughout the experimental period. One month after PCP application, the numbers of aerobic bacteria increased markedly in the surface water and oxidative-layer in Plot RR as compared with those of control. This pattern seemed to be that of partial sterilization. In Plot 100 RR, the number of aerobic bacteria decreased markedly in the surface water and remained almost constant in all soil layers, indicating that sterilization and repression of growth occurred in the respective layers.

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The purpose of this study was to clarify the effects of pentachlorophenol (PCP) on bacterial flora in the reductive-layer of water-logged soil, especially in its upper part (0-5cm depth after removing the oxidative-layer), by counting the numbers of several kinds of bacteria. PCP powder (free phenol) was applied to the surface-water of water-logged soil at a recommended rate (2.67g/m², Plot RR) and at 100 times the recommended rate (267g/m², Plot 100 RR). The effect of such applications on the changes in total numbers of aerobic bacteria was not clear. However, the effects on the changes in both numbers of PCP tolerant bacteria and gram-negative ones were clearly recognized. In Plot RR the number of bacteria tolerant to 10ppm and/or 100ppm PCP and gram-negative ones increased greatly about one month after PCP application. The increase in the number of bacteria tolerant to 10ppm PCP was larger than that of gram-negative ones. This means that PCP tolerant bacteria may consist of both gram-positive and gram-negative ones. The numbers of both bacteria also decreased following the decrease in concentration of PCP. After about 17 months the numbers of bacteria in Plot RR were almost the same as those in the control plot. On the other hand, in Plot 100 RR, the number of bacteria tolerant to 100ppm PCP increased largely and remained at a high level throughout the experimental period. Both the numbers of bacteria tolerant to 10ppm PCP and gram-negative ones decreased immediately after the application and remained at a lower level than those in Plot RR and control.

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Changes of chlorophyll, carotene and carbohydrate content in Chinese cabbage leaves applied with 15 organophosphorus insecticides were analyzed. Amounts of chlorophyll and carotene per fresh leaf decreased with treatments of fenitrothion, fenthion and chlorfenvinphos which showed leaf burn, and with phosalone, phenthoate and chlorpyriphos-methyl which showed chlorosis. The rate of decrease of carotene content was more rapid than that of chlorophyll, and chlorosis was retarded by shading after spraying in Chinese cabbage plant applied with phosalone or chlorpyriphos-methyl. Therefore, with these insecticides it is assumed, that chlorosis appeared by the photodecomposition of chlorophyll due to the lack of carotene. Total carbohydrate was decreased in Chinese cabbage leaves applied with insecticides, although they showed no phytotoxic symptoms. The degree of decrease was similar to that of chlorophyll. The decrease of carbohydrate content depends on the decrease of starch and soluble sugar. In leaves applied with dimethoate, which had the same value of chlorophyll content as control no symptoms showed on the young leaves, and the amount of carbohydrate (especially starch) decreased in both young and old leaves.

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N-Allylaminoacetonitrile hydrochloride (AAN) shows preventive activity against diseases caused by Fusarium oxysporum. AAN affected neither the growth of F. oxysporum nor the pathogenicity itself. No substance toxic to the pathogen was detected in the juice of plants treated with the compound. Enhancement of the peroxidase and polyphenoloxidase activities and accumulation of the total phenol were observed in the roots of AAN-treated plants. Accumulation of lignin in the roots and increase of incorporation of ¹⁴C(U)-glucose into cell walls were also recognized by the application of AAN. It is suggested that AAN exhibits a preventive activity through the increase of resistance to F. oxysporum resulting from physiological changes in host plants.

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On single oral administration of 5mg/kg of ¹⁴C-tolclofos-methyl [Rizolex^®, O, O-dimethyl O-(2, 6-dichloro-4-methylphenyl) phosphorothioate] labeled at the 4-methyl group to both sexes of rats and mice, approximately 87 to 91% of the radiocarbon administered was excreted into the urine and feces within 1 week. The total ¹⁴C-residue in the animal bodies 1 week after administration was less than 1% of the dose. The results of tissue analysis showed very low ¹⁴C-residue in the tissues, although a somewhat higher amount was found in the hair. More than 14 metabolites were detected in the excreta of both animal species. Of these, 13 metabolites were found in common in both rats and mice. The amounts of these metabolites differed between rats and mice, although no significant differences were found between male and female in either animal species. In both animals, tolclofos-methyl was mainly metabolized via oxidative desulfuration of the P=S group to P=O group, oxidation at the 4-methyl group and cleavage of the P-O-aryl and P-O-methyl linkages. The main metabolite was 3, 5-dichloro-4-hydroxybenzoic acid, which was excreted as free form in rats, but further conjugated with glycine in mice.

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Erectin, a pheromone of the azuki bean weevil, Callosobruchus chinensis L., which induces the male to extrude his genital organ and to attempt copulation, was found to consist of two synergistically acting fractions, neither having any activity. One was a mixture of several hydrocarbones: 3-methylpentacosane, 11-methylheptacosane, 3-methylheptacosane, 11-methylnonacosane, 13-methylnonacosane, 11, 15-dimethylnonacosane, 13-methylhentriacontane, 9, 13-dimethylhentriacontane and 11, 15-dimethyltritriacontane; the other was a dicarboxylic acid, (E)-3, 7-dimethyl-2-octene-1, 8-dioic acid. This copulation release pheromone was distinct from the female sex attractant and was released from both sexes, but affected only the male.

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The effects of carbofuran on some soil microbial activities—nitrogen mineralization, nitrification, nitrogen-fixation by blue-green algae, and urea hydrolysis—were investigated in the laboratory and the greenhouse. The addition of 10μg a. i. carbofuran per gram dried soil had no inhibitory effect on the mineralization of native soil nitrogen. Nitrifying activity was enhanced in flooded soil treated with 10, 20, 50, and 100ppm a. i. carbofuran. Nitrifying activity increased with increasing carbofuran concentration. The growth of blue-green algae was promoted by the addition of 6kg a. i. carbofuran/ha to the floodwater. Subsequently, a marked increased in the acetylene reduction activity of carbofuran-treated floodwater was obtained. Turbidity and an abundance of green algae distinguished the untreated floodwater from the carbofuran-treated one. The positive effect of carbofuran on phototrophic N₂-fixation appeared after its decomposition. The addition of up to 15ppm a. i. (μg/ml floodwater) carbofuran had no effect on the acetylene-reduction activity of Gloeotrichia sp., but 20ppm a. i. caused a significant lowering of that activity. The rate of urea hydrolysis appeared to be faster in dryland than in flooded soil. The addition of 50ppm a. i. carbofuran did not affect the rate of urea hydrolysis.

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[in Japanese]

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