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Mitsuaki TAKENAKA, Shuichiro KIMURA, Toshinobu TANAKA, Takuo WADA
1992 Volume 17 Issue 4 Pages
205-211
Published: November 20, 1992
Released on J-STAGE: August 05, 2010
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A new azole fungicide, pefurazoate (4-pentenyl (
RS)-2-[(2-furylmethyl) (imidazol-1-ylcarbonyl) amino] butanoate, Healthied
®) has one Chiral carbon center in its structure. From optically active 2-aminobutanoic acid, we prepared two enantiomers of pefurazoate, (
R)-isomer and (
S)-isomer, whose optical rotations in methanol were [α]
20D+10.7 and [α]
20D-9.90, respectively, and studied their antifungal activity and ergosterol biosynthesis in
Gibberella fujikuroi. The antifungal activity of the (
S)-isomer was about 30 times higher than that of the (
R)-isomer. At 0.24ppm, the
in vitro inhibition of ergosterol biosynthesis by the (
S)-isomer was four times higher than by the (
R)-isomer. These results indicate that the (
S)-isomer of pefurazoate is an active form fungicidal to
G. fujikuroi.
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Mitsuaki TAKENAKA, Keisuke HAYASHI, Tohru OGAWA, Shuichiro KIMURA, Tos ...
1992 Volume 17 Issue 4 Pages
213-220
Published: November 20, 1992
Released on J-STAGE: August 05, 2010
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Mutants of
Gibberella fujikuroi were obtained by selection from a large number of conidia of a wild type field isolate of the fungus on agar plates containing lethal concentration of a sterol demethylation inhibitor, pefurazoate. The mutants isolated from the colonies grown on the plates had higher minimal growth-inhibitory concentrations of pefurazoate and the EC
95 values were higher than that for the mother isolate but only a small increase was observed in the EC
50 values. Though the slope of the dosage-response curve was changed in the mutants, the mechanism of action of the fungicide in a mutant proved to be its inhibition of sterol 14α-demethylation as shown by an experiment on inhibition of ergosterol biosynthesis using
14C-acetate. Gibberellin production in the mutants in liquid culture was tested by bioassay of gibberellins and assay of gibberellin A
3 using HPLC. Mutants were also tested for their virulence to rice plants. Decreased virulence due to decreased production of gibberellins was observed in the mutants. A mutational change in a site related to 14α-demethylation in ergosterol biosynthesis and to kaurene oxidation in gibberellin biosynthesis in common is discussed.
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Shinoi SAKATA, Toshiyuki KATAGI, Jun YOSHIMURA, Nobuyoshi MIKAMI, Hiro ...
1992 Volume 17 Issue 4 Pages
221-230
Published: November 20, 1992
Released on J-STAGE: August 05, 2010
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Degradation of diethofencarb [Isopropyl 3, 4-diethoxycarbanilate] was studied in two soils under laboratory conditions with
14C preparations labeled separately at the phenyl ring and the C-2 position of the isopropyl group. Its half-life of disappearance was 0.3 to 6.2 days in aerobic upland soils. The major metabolite was a nitrated derivative at the 6-position of the phenyl ring of diethofencarb, which amounted to 2.4-4.7% of the applied
14C throughout the incubation period. Both of the
14C-labeled diethofencarbs were mineralized to
14CO
2 in soils amounting to 30.5-57.0% of the applied
14C after a 270-day incubation. Diethofencarb slowly degraded under anaerobic upland conditions and hardly degraded in sterilized soils. Diethofencarb was present in an effluent from sand containing organic matter by less than 0.1%, but it and its nitrated derivative did not leach into water from soils containing organic matter by more than 3%.
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Motohiro TOMIZAWA, Izuru YAMAMOTO
1992 Volume 17 Issue 4 Pages
231-236
Published: November 20, 1992
Released on J-STAGE: August 05, 2010
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In a radio receptor assay on the binding at the [
3H]α-bungarotoxin binding site to the nicotinic acetylcholine receptor (nAChR) obtained from housefly and honeybee head membranes, nicotine, nornicotine, anabasine and dihydronicotyrine, all with highly basic nitrogen, had a strong binding affinity, whereas myosmine, nicotyrine and cotinine, with low basic nitrogen, did not. Structure-binding relationships of the above nicotinoids and pyridylmethylamines mostly coincided with the previously studied relationships to the insecticidal activity, the effect on nerve activity and the inhibition of acetylcholinesterase (AChE). Both enantiomers of nicotine had an affinity for nAChR, although the affinity was higher in the
l-form than in the
d-form. Imidacloprid interacted at the same site on the nAChR, but oxadiazolone, a potent AChE inhibitor, had no affinity.
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Makoto FUJIMURA, Takashi KAMAKURA, Isamu YAMAGUCHI
1992 Volume 17 Issue 4 Pages
237-242
Published: November 20, 1992
Released on J-STAGE: August 05, 2010
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In the presence of 0.5μg/ml diethofencarb, conidia of a benzimidazole-resistant mutant of
Neurospora crassa germinated, with distorted, swollen germ tubes. Diethofencarb induced scattered nucleus and inhibited mitotic nuclear division in the resistant strain. The morphological abnormality was quite similar to the one observed in the wild-type strain treated with carbendazim (MBC). Diethofencarb, however, did not morphologically affect the germ tubes and nuclei of a wild-type strain. Diethofencarb formed a complex
in vitro with a protein present in the mycelial extracts of the resistant mutant. The binding protein of the resistant strain was retained on a DEAE-Sephadex A-50 and eluted with 0.5M KCl. The molecular weight of the binding protein was estimated 105, 000 by gel filtration on Sephacryl S-200 chromatography. The data well coincide with those on the MBC-binding protein in the wild-type strain, suggesting that diethofencarb was selectively toxic to the benzimidazole-resistant strain by binding to the tubulin.
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Fungitoxic Activity of N-Phenylformamidoximes (Part 2)
Akira NAKATA, Sho HASHIMOTO, Shinsuke SANO, Koichi HAYAKAWA
1992 Volume 17 Issue 4 Pages
243-249
Published: November 20, 1992
Released on J-STAGE: August 05, 2010
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N-(3, 5-Dichloro-4-propynyloxyphenyl)-
N′-methoxyformamidine (DCPF) and
N-(3-chloro-4, 5-dipropynyloxyphenyl)-
N′-methoxyformamidine (CDPF) clearly showed negatively correlated cross-resistance to benzimidazoles
in vitro as well as
in vivo. These compounds were remarkably efficacious in control of Cercospora leaf spot of sugar beet infected by isolates highly resistant (HR) or moderately resistant (MR) to benzimidazoles, but no efficacy was found against the infection by weakly resistant (WR) isolates. The efficacy was also remarkable in control of gray mold of kidney bean infected by HR isolates, but not by MR isolates. These results reflected the antifungal activities
in vitro. DCPF and CDPF showed not only preventive but also remarkable curative and residual efficacies in control of gray mold and Cercospora leaf spot. In addition, they exhibited systemic efficacy in controlling the diseases.
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Synthesis and Biological Activity of 1, 2, 4-Thiadiazolines (Part 1)
Kenji HAGIWARA, Sho HASHIMOTO, Susumu SHIMODA
1992 Volume 17 Issue 4 Pages
251-259
Published: November 20, 1992
Released on J-STAGE: August 05, 2010
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Seventy 5-arylimino-Δ
3-1, 2, 4-thiadiazolines were synthesized and their fungicidal activities were examined. Most of the tested compounds exhibited control efficacy
in vivo, especially against cucumber downy mildew (
Pseudoperonospora cubensis). The fungitoxic properties of the compounds strongly suggested that their primary mode of action is the inhibition of SH-enzyme. Among the series of compounds, 5-(4-chlorophenylimino)-2-methyl-3-phenyl-Δ
3-1, 2, 4-thiadiazoline (
1) was most active against cucumber downy mildew. The activity varied with substituents at 2-, 3- and 5-positions of the thiadiazoline nucleus. Considering the structure-activity profiles and the chemical reactivity of the molecules, the reactivity of the 1, 2, 4-thiadiazoline moiety with SH group may significantly affect the inhibition of the SH-enzyme. A combination of substituents on the 1, 2, 4-thiadiazoline ring to control the reactivity at some suitable positions seems to be important for fungicidal activity.
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Tadataka TSUDA, Junichi TAMURA, Hiroo USDA, Itsuo ICHIMOTO
1992 Volume 17 Issue 4 Pages
261-265
Published: November 20, 1992
Released on J-STAGE: August 05, 2010
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With diaminomaleonitrile (DAMN) as starting material, 14 kinds of esters (
II-a and
II-b series) and two kinds of amides (
III-a and
III-b) were prepared from 2, 3-dimethyl-5-(2, 5-dimethyl- and 2, 5-dichloro-phenylaminocarbonyl)-6-pyrazinecarboxylic acids (
I-a and
I-b). Seventeen kinds of
N-alkylamides (
V-a,
V-b and
V-c series) were prepared from
I-a,
I-b and
I-c having a 2, 5-dimethoxyphenylaminocarbonyl group at 5 position, respectively. Five kinds of
N,
N-dialkylamides (
VI-a series) were also prepared from
I-a through its acid chloride (
IV-a). All the compounds were examined for phytotoxicity, and several
N-alkylamides (
V-a series, R
1=Pr,
iso-Pr, Bu,
iso-Bu,
sec-Bu and
iso-Am) were found to have a certain phytotoxic action against Cos lettus and American millet in germination tests and a certain herbicidal activity against paddy field plants.
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Muney SERIT, Munetaka ISHIDA, Katsuyasu NAKATA, Mujo KIM, Shozo TAKAHA ...
1992 Volume 17 Issue 4 Pages
267-273
Published: November 20, 1992
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Neem oil (HN) deterred feeding by
Reticulitermes speratus in a no-choice bioassay. A methanol extract of HN (HN-01) was 4-fold more active than HN. Twelve other methanol extracts were subsequently evaluated, of which six were potent (PC
95≤1.0%w/w), three moderate (PC
95=1-3%w/w), and the remaining three inactive (PC
95 beyond bioassay limits). Eleven main limonoids were purified from the active chromatographic fractions of HN-01, which accounted for 81.5% of its activity. No acute toxicity was found, although
R. speratus given doses higher than estimated PC
95 tended to die faster than unfed ones. This suggests a possible use of potent neem extractives for termite control.
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Yoshihisa OZOE, Kazuo MOCHIDA, Toshiie NAKAMURA, Tomoe HOSAKA, Morifus ...
1992 Volume 17 Issue 4 Pages
275-277
Published: November 20, 1992
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Arata KATAYAMA, Satoko UCHIDA, Shozo KUWATSUKA
1992 Volume 17 Issue 4 Pages
279-281
Published: November 20, 1992
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Masako OHSHIMA, Sumiko YOSHIDA, Shoji SAITO, Nobuyoshi MIKAMI, Masatos ...
1992 Volume 17 Issue 4 Pages
283-285
Published: November 20, 1992
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Roongnapa KORPRADITSKUL, Vichai KORPRADITSKUL, Shozo KUWATSUKA
1992 Volume 17 Issue 4 Pages
287-289
Published: November 20, 1992
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Jun SEKIZAWA, Hiroko SERIZAWA
1992 Volume 17 Issue 4 Pages
291-294
Published: November 20, 1992
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Jun SEKIZAWA, Chiyoko OHTAKE
1992 Volume 17 Issue 4 Pages
295-300
Published: November 20, 1992
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Eiichi TAKAHASHI
1992 Volume 17 Issue 4 Pages
S291-S296
Published: November 20, 1992
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Kazushige YOKOTA
1992 Volume 17 Issue 4 Pages
S297-S305
Published: November 20, 1992
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[in Japanese]
1992 Volume 17 Issue 4 Pages
S309-S313
Published: November 20, 1992
Released on J-STAGE: August 05, 2010
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[in Japanese]
1992 Volume 17 Issue 4 Pages
S315-S318
Published: November 20, 1992
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[in Japanese]
1992 Volume 17 Issue 4 Pages
S319-S321
Published: November 20, 1992
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[in Japanese]
1992 Volume 17 Issue 4 Pages
S323-S325
Published: November 20, 1992
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Registration Department, Agricultural Chemicals Di
1992 Volume 17 Issue 4 Pages
S327-S335
Published: November 20, 1992
Released on J-STAGE: August 05, 2010
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In order to investigate toxicological properties of Dazomet, a number of toxicological studies were carried out with DAZOMET. In addition, the toxicological features of MITC, a major metabolite of Dazomet, were also tested. The studies show that the acute toxicity, subacute toxicity, and long-term toxicity are rather low. DAZOMET is neither irritating nor sensitizing to the skin. Inhalation risk can be excluded under practical conditions. No influence on reproduction parameters was observed, and no signs of teratogenic effects were noted. DAZOMET is neither mutagenic nor carcinogenic.
Withholding values have been set for the registration; 0.2ppm for vegetables and for potatoes, and 0.1ppm for fruits and for sugar crops. Dazomet products named BASAMID MG and GASTURD MG were registered to JMAFF on November 7, 1991 as a soil sterilant for a number of edible crops as well as for ornamentals and tobacco.
A safety risk for Dazomet is not to be expected as far as it is used in accordance with the established safe use standard.
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