Polyoxin

Polyoxin 化学特性,用途語,生産方法

• 説明

  Polyoxin was found in the culture broth of Streptomyces cacaoi var. asoensis by Suzuki et al. in 1965. It consists of several closely related components, A through O, and shows activity against phytopathogenic fungi by inhibition of cell-wall chitin synthesis. Polyoxin has been used in agriculture against fungal infections, especially Alternaria leaf spot in vegetables and fruits.

• 使用

  The fungicidal activities of polyoxins reported on many plant pathogens, including Alternaria spp. and Rhizoctonia zoctonia spp. (24,25).
  Polyoxin B is used for control of Alternaria spp. and powdery mildews in apples and pears; Botrytis cinerea in vines and aubergines; powdery mildews in roses, chrysanthemums, and melons; blight of carnation; powdery mildew, brown spot, and gray mold in tobacco; powdery mildew and gray mold in strawberries; leaf mold, early blight, and gray mold in tomatoes; powdery mildew, gray mold, Sclerotinia erotinia spp. rot, and Corynespora melonis in cucumbers; Alternaria spp. blight in carrots; purple blotch in leeks. Patent: JP 493008 Formulation types: WP; EC; SG. Mixes with captan; oxine-copper; iminoctadine triacetate. Compatibility: Incompatible with alkaline materials. Tradename “Polyoxin AL.”
  Polyoxin D zinc salt is used for control of sheath blight (Rhizoctonia solani) in rice; canker in apples and pears; Rhizoctonia solani, Drechslera spp., Bipolaris spp., Curvularia spp., and Helminthosporium spp. in lawn turf. Formulation types: WP; PA. Mixes with thiram; propiconazole. Compatibility: Incompatible with alkaline materials. Tradenames “Kakengel” (zinc salt); “Polyoxin Z” (zinc salt); “Stopit.”
  Application of polyoxins can be made at any growth stage of rice plants without causing phytotoxicity even at 800-ppm application. Foliar sprays of 200 ppm of polyoxins have produced no phytotoxicity on all the other crops tested.

• 代謝

  Polyoxin B causes a marked abnormal swelling on germ tubes of spores and hyphal tips in Alternaria spp., and this makes the pathogen noninfectious. In a cellfree system of Neurospora crassa, polyoxin D inhibits the incorporation of N-acetyl-glucosamine (GlcNAc) into chitin in a competitive manner between UDP-GlcNAc and polyoxin D; the pyrimidine nucleoside moiety of the antibiotics was shown to fit into the binding site of the enzyme protein, and the carbamoylpolyoxamic acid moiety of polyoxins stabilizes the polyoxin-enzyme complex (26).
  Polyoxin-resistant strains of A. alternata were recognized in pear orchards after several years of intensive use of the antibiotics. The resistance was suggested to be caused by a lowered permeability of the antibiotic through the cell membrane into the site of chitin synthesis (27).

• Toxicity evaluation

  Acute oral LD₅₀ of polyoxin B for male rats 21, female rats 21.2, male mice 27.3, and femalemice 22.5 g/kg. Acute percutaneous LD₅₀ for rats >2 g/kg. Nonirritant to mucous membranes and skin (rats). Inhalation LD₅₀ (6 h) for rats 10 mg/L air. NOEL (2 y) for rats and mice >48-g/kg diet. Toxicity class EPA (formulation) IV.
  Acute oral LD₅₀ of polyoxin D for male rats and female rats >9.6 g/kg. Acute percutaneous LD₅₀ for rats >750 mg/kg. Inhalation LD₅₀ (4 h) for male rats 2.44, female rats 2.17 mg/L air. NOEL (2 y) for rats >50, mice >40 g/kg diet. Toxicity class EPA (formulation) III (WP).

Polyoxin 生産企業

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