Isolation of Pentoxazone-Transforming Microorganisms from Soil: Their Characteristics and Metabolites
Five microbial strains which have pentoxazone ［3-(4-chloro-5-cyclopentyloxy-2-fluorophenyl)-5-isopropylidene-1,3-oxazolidine-2,4-dione］-transforming abilities were isolated from Ushiku paddy field soil. These strains, designated as 1B, 2B, 7B, 21B and 9A, have been tentatively identified by their morphological and physiological characteristics: Pseudomonas fluorescens, Bradyrhizobium japonicum, two pathovars of Xanthomonas oryzae and Bacillus sp., respectively. These isolates favored or tolerated the lower oxygen concentration than air though they belong to aerobes. These isolates partly modified pentoxazone molecule to afford five different metabolites. Strains 1B and 2B produced A-0505 ［N-(4-chloro-5-cyclopentyloxy-2-fluorophenyl)-2-oxo-3-methylbutanamide］. Strain(s) 7B and 21B produced, respectively, A-0480 (4-chloro-5-cyclopentyloxy-2-fluoroaniline) and A-1374 ［N-(4-chloro-5-cyclopentyloxy-2-fluorophenyl)-2-hydroxy-3-methylbutanamide］ after their transient accumulation of A-0505. Strain 9A produced two monohydroxylated compounds on cyclopentyl moiety: hydroxylated-pentoxazone and hydroxylated-A-0505. Strains 7B, 21B and 9A were able to transform A-0505 when it was provided as the initial substrate. This indicates that A-0505 could be a metabolic intermediate of these strains.
Key words: pentoxazone, soil microorganisms, isolated strains, pour plate, spread plate, cometabolism.
Resistance against Fusarium Wilt Induced by Non-Pathogenic Fusarium in Ipomoea tricolor
The cuttings of morning glory seedlings (Ipomoea tricolor cv. heavenly blue) were susceptible to Fusarium oxysporum f. sp. batatas (PF), and showed the typical fusarium wilt symptom. By using the reduction of chlorophyll content in cotyledons as the quantitative index of the disease symptom, we found that the pretreatment with the non-pathogenic isolate of Fusarium (NPF; F. oxysporum 101‐2), which has been practically used as a biological control agent for fusarium wilt of sweet potato, suppresses the symptom significantly. Dead NPF bud-cells could not induce resistance. The supernatant of NPF culture after centrifugation at 15,000×k for 20 min, also induced resistance. The activity of the supernatant was lost by heating. The factor(s) associated with the induction of resistance was considered to be thermolabile chemical component(s) produced by NPF. This experimental model may be facile and useful for analyzing the chemical basis of the biological interaction among PF, morning glory and NPF.
Key words: morning glory, fusarium wilt, non-pathogenic Fusarium, disease suppression, etiolation of cotyledons, chlorophyll content.
Synthesis and Insecticidal Activity of [1(2H),2'-Bipyridin]-2-one Derivatives
A series of [1(2H),2'-bipyridin]-2-one derivatives were synthesized and their insecticidal activity against German cockroaches and houseflies was evaluated. The strength of activity varied markedly depending upon the substituents and their positions on the pyridone and the pyridine ring. Electron-withdrawing substituents at the 3, 3', 5 and 5'-positions on both rings are required for the insecticidal activity, especially against German cockroaches. Furthermore, a couple of trifluoromethyl groups at the 5 and 5'- positions on both rings are essential for the activity. Among all compounds tested, a chlorine atom at the 3-position on the pyridone ring, and a chlorine atom, a fluorine atom or a trifluoromethyl group at the 3'-position on the pyridine ring were more preferable.
Key words: [1(2H),2'-bipyridin]-2-one derivatives, pyridone ring, pyridine ring, German cockroaches, houseflies, insecticide.
Effect of White Carbon Contained in Water Insoluble Polymer Membrane of Time-Controlled Release Granule on Release Profile of Metominostrobin
We investigated the effect of white carbon (hydrated silicon dioxide) contained in water insoluble polymer membrane on release profiles of metominostrobin from the time-controlled release granule (TCRG) containing metominostrobin. As the amount of white carbon increased, the lag time for release was shortened and the release rate became faster. Thus, the changes in both lag time and release rate were thought to be related to water permeability into the TCRG and tensile strength of the membrane induced by it. We also made a single regression model and a logistic model to predict release profile based on the amount of white carbon in TCRG using computer program NLIN procedure of SAS (Statistical Analysis Systems). As a result, the actual release profile fitted in a three parameter logistic model by non linear least-squares method.
Key words: metominostrobin, time-controlled release granule (TCRG), lag time, three parameter logistic model, white carbon.
Population Dynamics of Sensitive- and Resistant-Phenotypes of Botrytis cinerea to Benzimidazole, Dicarboximide, and N-Phenylcarbamate Fungicides in Korea
Key words: Botrytis cinerea, fungicide resistance, dicarboximide, benzimidazole, N-phenylcarbamate.
Determination of Chlorpyrifos Residue in Andosol Upland Soils Using Methanol-Phosphoric Acid Extraction
Key words: chlorpyrifos, andosol, persistence, residue, release by acid treatment.
Synthesis and Insecticidal Activity of O-Aryl N-Alkoxycarbonyl-N-alkylmethylphosphonamidothionates
Key words: synthesis, insecticidal activity, O-aryl N-alkoxycarbonyl-N-alkylmethylphosphonamidothionates.
Insecticide Resistance and Insensitive Acetylcholinesterase in Small Brown Planthopper, Laodelphax striatellus
Key words: insecticide resistance, insecticide susceptibility, small brown planthopper, Laodelphax striatellus, acetylcholinesterase, aliesterase.
Effect of Metominostrobin on Respiratory Activity of Rhizoctonia solani and Its Efficacy for Controlling Rice Sheath Blight
Key words: metominostrobin, Rhizoctonia solani, rice sheath blight, respiration.
Selection of Optimal Time-Controlled Release Granule Formula of Metominostrobin
Key words: metominostrobin, controlled release system, time-controlled release granule (TCRG).
Ellagitannin Toxicity in the Free-Living Soil-Inhabiting Nematode, Caenorhabditis elegans
Key words: ellagitannin, nematode, Caenorhabditis elegans, L1 larva, young and egg-bearing adults, toxicity.
Lethal Activity of Gallo- and Condensed Tannins against the Free-Living Soil-Inhabiting Nematode, Caenorhabditis elegans
Key words: gallotannin, condensed tannin, nematode, Caenorhabditis elegans, lethal activity.
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