Absorption, translocation and metabolism of chlomethoxynil (X-52) in plants.

Niki, Yoshio; Kuwatsuka, Shozo; Yokomichi, Isao

doi:10.1271/bbb1961.40.683

Cited by 9 publications

(3 citation statements)

References 1 publication

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“…A molecular ion (M -31) at m/z 404 and ion fragments at m/z 125 and 151 ( 153-2) suggested that the methoxy group on the s-triazine ring was oxidized to an unstable hydroxymethyloxy (-OCH 2 OH) intermediate (III) that degraded during FAB/MS and, to a limited extent, during TLC with a loss of formaldehyde (HCHO) to form IV (Figure 1), a slightly more polar product that cochromatographed (TLC) with the reference standard, 1-(4-hydroxy-6methyl-1,3,5-triazin-2yl)-3-[2-(3,3,3-trifluoropropyl)phenylsulfonyl]urea (Table 1). Similar intermediate oxidation products of O-demethylation have been reported in rice as metabolites of the herbicides chlomethoxynil (Niki et al, 1976) and bensulfuron (Beyer et al, 1988). Prosulfuron O-demethylation and the formation of 1-(4-hydroxy-6-methyl-1,3,5-triazin-2yl)-3-[2-(3,3,3-trifluoropropyl)phenylsulfonyl]urea (IV) as a major oxidation product have been reported with induced microsomes isolated from shoots of tolerant grain sorghum seedlings (Moreland et al, 1996).…”

Section: Separation Of Microsomal Oxidation Productssupporting

confidence: 68%

Cytochrome P450-Dependent Hydroxylation of Prosulfuron (CGA 152005) by Wheat Seedling Microsomes

Frear

Swanson

1996

J. Agric. Food Chem.

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Microsomes isolated from shoot tissues of etiolated wheat seedlings (Triticum aestivum L. var. Olaf) oxidized the sulfonylurea herbicide prosulfuron (CGA 152005). One major and two minor enzymatic oxidation products were isolated and identified by negative ion FAB/MS and cochromatography (TLC and HPLC) with reference standards. Identification of the major oxidation product (I) as 1-(4-methoxy-6-methyl-1,3,5-triazin-2-yl)-3-[2-(3,3,3-trifluoropropyl)-5-hydroxyphenylsulfonyl]urea was confirmed by proton NMR spectroscopy. Minor oxidation products were tentatively identified as 1-[4-(hydroxymethyl)-6-methoxy-1,3,5-triazin-2-yl]-3-[2-(3,3,3-trifluoropropyl)phenylsulfonyl]urea (II) and an intermediate oxidation product 1-[4-[(hydroxymethyl)oxy]-6-methyl]-1,3,5-triazin-2-yl]-3-[2-(3,3,3-trifluoropropyl)phenylsulfonyl]urea (III) that degraded to 1-(4-hydroxy-6-methyl-1,3,5-triazin-2-yl)-3-[2-(3,3,3-trifluoropropyl)phenylsulfonyl]urea (IV). Microsomal oxidation of prosulfuron required NADPH and molecular oxygen. Constitutive enzyme activity was increased 5−28-fold by induction with ethanol and with the herbicide safeners naphthalic anhydride or cloquintocet-mexyl (CGA 185072) and by combinations of naphthalic anhydride or cloquintocet-mexyl with ethanol. Inhibition of enzyme activity by CO in the dark was reversible by light. Other inhibitors of prosulfuron oxidation included tetcyclacis, piperonyl butoxide, cytochrome c, polyclonal antibodies raised against wheat cytochrome c (P450) reductase, and the herbicides bifenox and linuron. Kinetic studies established that the apparent K m for prosulfuron was 12.6 ± 1.1 μM and that bifenox and linuron were noncompetitive and mixed-type inhibitors of prosulfuron oxidation, respectively, with apparent K i values of 210 and 59 μM. Keywords: Wheat; microsomes; prosulfuron oxidation; cytochrome P450

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Section: Separation Of Microsomal Oxidation Productssupporting

confidence: 68%

Cytochrome P450-Dependent Hydroxylation of Prosulfuron (CGA 152005) by Wheat Seedling Microsomes

Frear

Swanson

1996

J. Agric. Food Chem.

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“…In preliminary dose–response experiments conducted with the WT biotype, WT seedlings were not killed with rates up to eight times the maximum fomesafen dose [ 38 ]. Other diphenylether herbicides, which are analogs of fomesafen (chlomethoxyfen and oxyfluorfen), are safe to use on rice postemergence [ 40 , 41 ]. Even though none of the rice plants (WT or transgenic T 1 ) were killed by foliar-applied fomesafen, all T 1 plants that harbored the ΔG210-Apppo2 transgene showed low injury, indicating a reduced phytotoxic effect of fomesafen.…”

Section: Discussionmentioning

confidence: 99%

Field-Evolved ΔG210-ppo2 from Palmer Amaranth Confers Pre-emergence Tolerance to PPO-Inhibitors in Rice and Arabidopsis

Carvalho-Moore

Rangani

Langaro

et al. 2022

Genes

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Resistance to protoporphyrinogen IX oxidase (PPO)-inhibitors in Amaranthus palmeri and Amaranthus tuberculatus is mainly contributed by mutations in the PPO enzyme, which renders herbicide molecules ineffective. The deletion of glycine210 (ΔG210) is the most predominant PPO mutation. ΔG210-ppo2 is overexpressed in rice (Oryza sativa c. ‘Nipponbare’) and Arabidopsis thaliana (Col-0). A foliar assay was conducted on transgenic T1 rice plants with 2× dose of fomesafen (780 g ha−1), showing less injury than the non-transgenic (WT) plants. A soil-based assay conducted with T2 rice seeds confirmed tolerance to fomesafen applied pre-emergence. In agar medium, root growth of WT rice seedlings was inhibited >90% at 5 µM fomesafen, while root growth of T2 seedlings was inhibited by 50% at 45 µM fomesafen. The presence and expression of the transgene were confirmed in the T2 rice survivors of soil-applied fomesafen. A soil-based assay was also conducted with transgenic A. thaliana expressing ΔG210-ppo2 which confirmed tolerance to the pre-emergence application of fomesafen and saflufenacil. The expression of A. palmeri ΔG210-ppo2 successfully conferred tolerance to soil-applied fomesafen in rice and Arabidopsis. This mutant also confers cross-tolerance to saflufenacil in Arabidopsis. This trait could be introduced into high-value crops that lack chemical options for weed management.

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“…While a substantial database exists on the metabolism and fate of herbicides and other individual compounds, these will only be briefly addressed to demonstrate the range of potential interactions. Chlomethoxynil, a nitrile class of herbicide, is prone to conjugation at the nitro group (Niki et al 1976); this can involve simple conjugation to form amino and diantino derivatives, or the formation of immobile conjugates with lipids and lignin. Anthracene absorbed by roots (Edwards 1986) was shown to be chemically altered in roots 91% of the time and leaves 99% of the time in bushbean.…”

Section: Metabolism Of Organic Residuesmentioning

confidence: 99%

Estimation of aerial deposition and foliar uptake of xenobiotics: Assessment of current models

Link¹,

Fellows²,

Cataldo³

et al. 1987

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The primary objective of this report was to review existing mathematical and/or computer simulation models that can be used to estimate xenobiotic deposition to and transport through (both cuticular and stomatal) vegetative surfaces. The secondary objective was to evaluate the potential for coupling the best of those models to the existing UTAB (Uptake, Translocation, Accumulation, and Biodegradation) model to be used for future xenobiotic exposure assessments. Here xenobiotic compounds are defined as airborne contantinants, both organic particulate and gaseous pollutants, that are introduced into the environment by man. In an attempt to simplify a portion of complexity of the question posed, a review of several potential classification systems for organic xenobiotics is also provided. Specifically this document provides a detailed review of the state-of-the-art models that addressed: I) aerial deposition of particles and gases to foliage; 2) foliar and cuticular transport, metabolism, and uptake of organic xenobiotics; and 3) stomatal transport of gaseous and volatile organic xenobiotic pollutants. Where detailed information was available, parameters for each model are provided on a chemical by chemical as well as species by species basis. Sufficient detail is provided on each model to assess the potential for adapting or coupling the model to the existing UTAB plant exposure model. Based solely on the literature evaluation, mathematical linking of these models is possible; however, the immediate utility of this "master" model would be questionable. The inability to adequately link these models at this time results from either a lack of empirical data for specific types of xenobiotics, and/or a lack of detailed understanding of controlling processes in the plant. Specific models are identified and recommendations for further research are provided for each area: I) wet and dry aerial deposition of xenobiotics; 2) foliar adsorption and cuticular transport of or garlic xenobiotics; and 3) stomatal transport of gaseous and volatile organic pollutants.

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Absorption, translocation and metabolism of chlomethoxynil (X-52) in plants.

Abstract: Rapid absorptionand degradation of chlomethoxynil were observed in seedlings of rice and barnyard millet. The amounts of absorption by rice and barnyard millet , at the 2-leaf and 4-leaf stages of plants, were determined in water and soil cultures.

Cited by 9 publications

References 1 publication

Cytochrome P450-Dependent Hydroxylation of Prosulfuron (CGA 152005) by Wheat Seedling Microsomes

Cytochrome P450-Dependent Hydroxylation of Prosulfuron (CGA 152005) by Wheat Seedling Microsomes

Field-Evolved ΔG210-ppo2 from Palmer Amaranth Confers Pre-emergence Tolerance to PPO-Inhibitors in Rice and Arabidopsis

Estimation of aerial deposition and foliar uptake of xenobiotics: Assessment of current models

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