Homology modeling of plant 4-hydroxyphenylpyruvate dioxygenase (4-HPPD) was carried out using structural information on the Pseudomonas fluorescens enzyme as a template. A three-dimensional structural model of the barley enzyme was investigated in detail to compare its catalytic pocket with that of the Pseudomonas enzyme. Striking conservation of the catalytic pocket provided a rational basis for designing potent 4-HPPD inhibitors by the in silico docking of compounds and model/template enzymes.
Key words: 4-HPPD, enzyme inhibitor, homology modeling, SWISS-MODEL.
Synthesis and characterization of anti-rice blast activity of pyrazole derivatives was described. Structure-activity relationship study indicated that a carboxyl group at 5-position of 1-methyl-1H-pyrazole played an important role in the activity and that a halogen atom such as a chlorine or bromine at 3-position enhanced the activity. Among the derivatives, 3-chloro-1-methyl-1H-pyrazole-5-carboxylic acid (CMPA) exhibited the highest anti-rice blast activity with the ED80 (80% effective dose, the concentration needed for 80% inhibition of disease development) of 0.05 mg/pot. CMPA did not have any significant effects on the hyphal growth, spore germination, and appressorium formation of Pyricularia oryzae, suggesting that CMPA induces systemic acquired resistance in rice plants.
Key words: carice blast, Pyricularia oryzae, systemic acquired resistance, pyrazolecarboxylic acid.
A rapid gas chromatographic method for determining organophosphorus pesticide residues in allium such as onion and welsh onion containing high levels of sulfur-matrices was studied. A sample was extracted with acetonitrile and the acetonitrile layer separated by salting-out. The extract was cleaned up with gel permeation chromatography, and then with a tandem silica-gel/PSA mini-column. The test solution was subjected to gas chromatography with a pulsed flame photometric detector. Organophosphorus pesticide residues in such sulfur-rich matrices were determined without any serious interfering peaks on the chromatograms by diluting the extracts 8-fold (0.25 g/ml of sample). No additional pretreatment to deactivate enzymes which caused interference was necessary. The rate of recovery of 36 organophosphorus pesticides from fortified onion and welsh onion ranged from 61 to 105% with the RSD usually 10% for five experiments. The detection limits of these pesticides were good (0.002-0.01 mg/kg) for monitoring organophosphorus pesticide residues in agricultural products including allium, except for degradable trichlorfon. The method was applied to onion and welsh onion to demonstrate its use in routine analysis.
Key words: organophosphorus pesticide residues, onion, welsh onion, sulfur-matrices, gas chromatography, pulsed flame photometric detector
In order to discuss the rate of dispersion of the resistance gene of Monochoria korsakowii, we quantitatively estimated the out-crossing rates using the herbicide resistance trait as a marker on experimental populations. Two insect species, Apis mellifera and Xylocopa circumvolans, were observed on the flowers and the estimated out-crossing rates ranged from 10.4 to 67.8% with an average of 36.2%. The finding indicates that the trait can be transmitted via pollen by bees and expressed in hybrid offspring and further implies that the subsequent spread of resistance can occur through pollen migration. Thus, the evolution of resis-tance will be rapid.
Key words: acaricidal acitivity, Tetranychus urticae, N-(1, 3, 4-thiadiazol-2-yl)pyrazole-5-carboxamides, N-(1, 3, 4-thiadiazol-2-yl)thiazole-5-carboxamides.
The effects of ethephon spraying on the growth development, flower bud stage and leaf color were studied in a summer-to-autumn-flowering chrysanthemum (Dendranthema grandiflorum (Ramat.) Kitamura) under open field conditions. The growth of all cultivars was slow until the last ethephon spraying stage, but that from the involucre formation stage to the floret formation stage was fast and growth before flowering was slow again. Leaf segments grew after rosette formation at high positions under a schedule of three 200 mg/l ethephon sprayings with 1000 mg/l for strong inhibition of flower bud differentiation. The plant height overtook that achieved with three 200 mg/l ethephon sprayings in eSeiunf and eSummer-yellowf cultivars. First growth using ethephon sprays with pinching was slower than that without pinching. Leaf color of flowers treated with ethephon sprays and pinching was more inhibited than that without pinching in all cultivars. Our results showed that, ethephon spraying inhibited early flower bud differentiation, growth of stems and change of leaf color to dark green, however, the stem length was longer than controls because the growth of stems is fast in summer-to-autumn-flowering chrysanthemum.
Key words: chrysanthemum, ethephon, flower bud differentiation, leaf color, plant height.
Current Topics and Problems Concerning Fungicides against Seed-Borne Pathogens in Vegetable and Ornamental Crops
Hajimu KOMADA and Koichi ASAGA
Key words: topics and problems, fungicides, seed-borne pathogens.
Takeshi NAKANO, Shigeo YOSHIDA and Tadao ASAMI
Key words: brassinosteroid, Arabidopsis, photomorphogenesis, chloroplast development, Brz.
Newly Registered Pesticides and Cancelled Pesticides in Calendar Year of 2002
Key words: registered pesticides, cancelled pesticides.
Key words: protein crystallography, crystallization, sparse matrix, fructose-1, 6-/sedoheptulose-1, 7-bisphosphatase, ascorbate peroxidase, glyceraldehyde-3-phosphate dehydrogenase.
A New Method for Measuring Plant Cuticular
Permeability without Using Radioisotopes
Key words: floating method, plant cuticular permeability,
Minireviews: Biotechnologies in
@Functions of ABC Transporters in Phytopathogenic Fungi
Key words: ABC transporter, multidrug resistance, pathogenicity, phytopahogenic fungi.
Studies on the Expression of Cytochrome
P450s by cDNA Array Tequnique: for the Search of New Insecticide
Targets and Elucidation of Resistance Mechanisms
Shinji KASAI and Takashi TOMITA
Key words: cDNA array, cytochrome P450 monooxygenase, ecdysone, Cyp312a1, insecticide resistance, target site.
Resistance to ALS-Inhibiting Herbicides in WeedsAkira UCHINO479
Key words: acetolactate synthase, ALS inhibitor, herbicide resistance, sulfonylurea, paddy weed.
Histidine Kinase Signal Transduction and Fungicide-Resistance in Fungi
Key words: histidine kinase, dicarboximide, phenylpyrrole, resistance.
His-Asp Phosphorelay in Plant Hormone Responses
Key words: plant hormones His-Asp phosphorelay, signal transduction.
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