The culture supernatant of Bacillus sp. bacteria showed growth inhibition against several kinds of fungi, especially plant pathogenic fungi. This strain was isolated as a microorganism, which remarkably inhibited the growth of Fusarium sp. on a potato-glucose agar medium. The strongest antifungal activity was observed when the strain was aerobically cultured in a medium containing 200g of potato extract, 20g of glucose and 2g of polypeptone per liter of water at pH 6.5 with a reciprocal shaker at 33-35°C for 2 days. The supernatants of about 30-fold dilution and about 20-fold dilution retained the antifungal activity against Pyricularia oryzae and Helminthosporium oryzae, respectively.

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An antifungal substance in the culture supernatant of Bacillus sp. bacteria seems to be water-soluble and acidic polypeptide. The antifungal activity was retained after the culture supernatant was heated at 121°C for 15min. Crude powder having an antifungal activity was obtained by both acidification and ammonium sulfate fractionation of the culture supernatant. The crude powder was loaded onto a DEAF-cellulose column and the column was eluted with a stepwise manner by raising the sodium chloride concentration in 50mM phosphate buffer (pH 6.8): 0.3M, 0.4M, 0.5M, 0.6M, 0.7M and 0.8M. Among them, fractions of F-II, F-III and F-IV eluted with 0.4M, 0.5M and 0.6M sodium chloride, respectively, were purified by gel filtration of Sephadex G-100. The purified powder showed a strong antifungal activity to Helminthosporium oryzae and Pyricularia oryzae which were used as the test organisms.

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Ferimzone (proposed common name), (Z)-2′-methylacetophenone 4, 6-dimethyl-2-pyrimidinylhydrazone, is a new fungicide with curative activity, which is effective against rice blast, leaf brown spot, stem-rot, and sheath blight by foliar treatment. The possibility of replacement of the hydrazone group in the ferimzone molecule by a pyrazole ring was investigated. As a result of the present study, the structure was remarkably modified by the replacement with alkyl-substituted pyrazoles which apparently resembled the hydrazone moiety and satisfied the prerequisites to the activity. A strategy for synthesizing pyrazole isosters and their fungicidal activities are described.

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With an aim to evaluate ecological effects of fenitrothion (MEP) sprayed aerially over a forest for control of pine sawyer beetles, residues of MEP in soil and aquatic systems (water, sediment, fish) were investigated. In soil, MEP concentration was 2.87-56.3ppm in the organic horizon on the 2nd day after application, and decreased to 0.164-0.546ppm after one year, which was 178-1060 times as high as that in the mineral horizon. MEP residues after one year were estimated to be 0.16-0.25% of the applied dosage. In water, maximum MEP concentrations were 93.9ppb in streams on the application day, 24.4ppb at the first rainfall after application, 2.31ppb in estuaries, 508ppb in a pond. MEP dropped in the streams ran off rapidly, and the remaining MEP in the forest ran off with the first rainfall after application. MEP effusions were estimated to be 0.71% and 0.0092% of the applied dosage with an 89mm rainfall on the 2nd day and with a 36mm rainfall on the 5th day after another application, respectively. MEP concentration in the small pond was relatively high, decreasing exponentially with a half-life of 1.1-2.4 days. Little MEP remained in sediments. MEP in carp changed in proportion to the concentration in the water, maximum concentrations being 2.33ppm in the carp in the streams and 20.6ppm in the carp in the pond. The ratios of MEP concentration in the carp to the water were 5.2-2000 in the streams and 70-690 in the pond.

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Effects of diphenyl ether (DPE) and DPE-type herbicides on porphyrin biosynthesis in cucumber seedlings were studied by ion-pair HPLC. The results: (a) Acifluorfen-methyl (AFM) did not increase the protoporphyrin IX (Proto IX) content in either etiolated cotyledons or white hypocotyls in the presence of 2, 2′-dipyridyl, which was synergetic with AFM in stimulating the accumulation of Proto IX in green cotyledons, although AFM has been reported to cause the accumulation of Proto IX by inhibiting protoporphyrinogen oxidase or stimulating ALA-synthesizing enzymes. AFM hardly affected the protochlorophyllide (Pchlide) level either, contrary to the hypothesis that AFM stimulates ALA-synthesizing enzymes. (b) HPLC chromatograms of porphyrin pigments indicated that nitrofen acts in the same way as AFM. (c) The light-independent m-substituted DPEs tested, the mode of action of which has not yet been clarified, stimulated the accumulation of Mg-Proto IX monomethyl ester both in green cotyledons and in white hypocotyls when combined with 2, 2′-dipyridyl. (d) Two DPE-type compounds, 3-chloro-2-[4-chloro-2-fluoro-5-(2-propynyloxy) phenyl]-4, 5, 6, 7-tetrahydro-2H-indazole (S-275) and ethyl 2-[4-nitro-1-(2, 3, 4-trichlorophenyl) pyrazoryl-5-oxy] propionate (OC-17595), caused Proto IX to accumulate in green cotyledons. This result strongly suggested that these compounds, although different from AFM in chemical structure, have the same mode of action as AFM. (e) 1, 3-Dimethyl-4-(2, 4-dichlorobenzoyl)-5-hydroxypyrazole (DTP), a Pchlide inhibitor, neither decreased Pchlide nor increased Proto IX, which disagreed with the previous result.

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Photodegradation of three tetrachlorodibenzo-p-dioxins (TCDDs), 1, 2, 3, 4-TCDD, 1, 3, 6, 8-TCDD, and 2, 3, 7, 8-TCDD, in dioxane solution was investigated under xenon lamp irradiation. The quantum yields (φ_λ) for direct photodegradation of these TCDDs were 1.009×10^-3, 2.798×10^-3, and 1.990×10^-2mol·einstein^-1, respectively, at 313nm, which is a wavelength usually used in determining the quantum yield of a test compound. However, the quantum yields of these TCDDs at wavelengths of the maximal photodegradation peak at more than 295nm were 2.133×10^-3, 3.020×10^-3, and 3.283×10^-2, respectively, at their maximal photodegradation peaks, and were higher than those at 313nm. Based on these quantum yields and the measured absorption spectra together with the solar intensity data available in the literature, we estimated the direct sunlight first-order photodegradation rate constants of these TCDDs under conditions of variable sunlight intensities on the surface of water bodies during various seasons at 40°N latitude. Also determined were the corresponding half-life times.

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The systemic fungicide flutolanil at 2μg/ml caused inhibition of the fungal growth and morphological changes, such as collapse of hyphae and infection cushions, of Rhizoctonia solani that was infecting rice leaf sheaths. Detectable ultrastructural changes in treated fungal cells were sparse cytoplasm and separation of the plasmamembrane from the cell wall at 6hr after treatment, suggesting that an osmotic shock was accompanied by the collapse. A succinate dehydrogenase complex (SDC) was histochemically more active in situ in infection cushions, and less active in hyphae of the flutolanil-untreated fungus. Flutolanil at 2μg/ml completely inhibited the SDC activity within 1hr after treatment. The determination of the ATP level in culture with luciferase showed that 2μg/ml flutolanil reduced ATP production by 50% within 2hr after treatment. The results presented in this paper provide the hypothesis that flutolanil inhibits succinate oxidation leading to decrease in ATP, which may cause sparse cytoplasm and reduce osmotic pressure inside fungal cells, thereby giving rise to collapse of the fungal cells.

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As we have reported monthly means of the sunlight UV energy in the FRA-greenhouse, monthly mean of the outdoor UV energy can be estimated from the relationship between outside UV intensity and UV intensity inside the FRA-greenhouse. In our measurement UV intensity on the outside was two times higher than UV intensity inside FRA-greenhouse in Chigasaki city. Thus the outdoor UV energy was estimated two times higher than the UV energy inside the FRA-greenhouse. In this way, the outside UV energy could be estimated by using this relation. We investigated the quantitative photolysis rate of aqueous solution of naproanilide (2-(2-naphthoxy)propionanilide), NOP (2-(2-naphthoxy)propionic acid) and chlornitrofen (2, 4, 6-trichlorophenyl 4-nitrophenyl ether) exposed to outdoor sunlight. The results showed that photolysis rate of naproanilide fitted to the exponential function, and its PL₅₀ value on the outside was the same as that inside the FRA-greenhouse. Delaying phenomenon was detected in the initial photolysis of NOP and chlornitrofen. It is not clear how they occur, so far. A probable reason is that another material is activated by the light and this activated material makes an opportunity for the photolysis of NOP and chlornitrofen. Once the reaction started, however, the photolysis rate approximated to an exponential function.

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The inhibitory activity (I₅₀) of fifteen sulfone analogs of 6-alkylthio-2-pyridyl methanesulfonates was measured against acetylcholinesterase preparations from Ageo and Izumi strains of Nephotettix cincticeps. The insecticidal activity of 6-alkylthio derivatives to both strains was highly related to the acetylcholinesterase-inhibitory activity of the corresponding sulfones when hydrophobicity factors (log k′) of the molecule perhaps participating in the transport process were taken into account. Variations in insecticidal activity was due to the total of structure-activity relationships in enzyme inhibition and transport process. The combination of hydrophobicity and steric parameter terms was quite similar in the two strains.

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The effects of four nonionic and two anionic surfactants on cucumber protoplasts were examined by light and electron microscopy. Two nonionic surfactants, polyoxyethylene (POE) (n=10) nonylphenylether and POE (n=5) laurylether, caused swelling of protoplasts, followed by their bursting. The bursting gave more destructive effects preferentially on lamellar structures of chloroplasts than the swelling. Two other nonionic surfactants, POE (n=10) oleylether and POE (n=20) stearylether, appeared to have little effects on the morphology of protoplasts by light microscopy, but electron microscopy revealed abundant spotty and linear, electron-transparent spaces in treated chloroplasts. Protoplasts were drastically destroyed by two anionic surfactants, Na-dioctylsulfosuccinate and Na-dibutylnaphthalene-sulfonate. Their entire structure was almost completely disrupted by these surfactants at 1000ppm. Among organelles, chloroplasts were preferentially sensitive to all test surfactants. All of nonionic surfactants caused at least some cytological changes in chloroplasts at their respective, critical micelle concentrations (cmc), while anionic surfactants worked heavy damages to chloroplasts and other organelles at concentration lower than cmc. The effect of each surfactant seemed to depend on its organelles, membranes of single organelle and molecular structure in the microscopic observation.

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The herbicide naproanilide [2-(2-naphthoxy)propionanilide] was hydrolyzed to 2-(2-naphthoxy) propionic acid (NOP) in perfused soil in a short time. The hydrolysis was retarded remarkably by NaN₃ and MTMC (m-tolyl N-methylcarbamate) a carbamate insecticide. NOP degraded rapidly after a lag period of about 10 days after the first amendment, and after the subsequent amendment it degraded rapidly without lag time. The degradation of NOP was also inhibited by NaN₃. Degradation products of NOP in the perfusate contained methyl 2-(2-naphthoxy) propionate (NOPM), 2-naphthol, 2, 6-naphthalenediol and 2-hydroxy-1, 4-naphthoquinone in small amount, and ¹⁴CO₂ from the ¹⁴C-naphthalene ring in large amount. NOP-degrading microorganisms were isolated from soil enriched with NOP, and they were identified as Pseudomonas sp. The bacteria proliferated only in an organic medium but in an inorganic salt medium containing NOP as a carbon source. The main metabolites of NOP were 2-naphthol, naphthalenediols and 2-hydroxy-1, 4-naphthoquinone. Naproanilide, however, was not degraded by this microbe.

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The Bruchid beetles, C. chinensis L. and C. maculatus F. grew in many kinds of beans, but not in kidney beans, Phaseolus vulgaris L. Extraction from kidney beans, chromatography and electrophoresis of the extract combined with bioassay for larval growth inhibition of C. chinensis using artificial beans resulted in the isolation of a growth inhibitor, a glycoprotein, whose molecular weight was ca. 48, 000 and isoelectric point, 4.46. The inhibitor was present at a level of 0.6% in kidney beans, and showed α-amylase-inhibitory activity, but it was not a trypsin inhibitor.

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Two fungicidal substances, Y-9 and Y-10, were isolated from the culture filtrate of Bacillus subtilis TM-105 during our screening for antimicrobial substances against phytopathogenic fungi. They were identified as lipopeptide antibiotics plipastatin A1 and B1, respectively. Plipastatins have been reported to be new inhibitors of phospholipase A₂, but their fungicidal activity has yet to be clarified. We report here the result of our investigation on the fungicidal activity of plipastatins.

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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