Characterization of Risks Associated with the Use of Molinate

Cochran, Roger C.; Formoli, Tareq A.; Pfeifer, Keith F.; Aldous, Charles N.

doi:10.1006/rtph.1997.1082

Cited by 41 publications

(22 citation statements)

References 23 publications

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“…It is used to control germinating broad-leafed and grassy weeds in rice paddies [3,4]. Toxicological studies showed that molinate could lead to adverse effects such as reproductive toxicity in mammals [5,6]. Bentazone is a post-emergence herbicide used for selective control of broadleaf weeds and sedges in beans, rice, corn, peanuts and others.…”

Section: Introductionmentioning

confidence: 99%

Removal of organic contaminants from soils by an electrokinetic process: The case of molinate and bentazone. Experimental and modeling

Ribeiro

Mateus

Rodríguez‐Maroto

2011

Separation and Purification Technology

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Section: Introductionmentioning

confidence: 99%

Removal of organic contaminants from soils by an electrokinetic process: The case of molinate and bentazone. Experimental and modeling

Ribeiro

Mateus

Rodríguez‐Maroto

2011

Separation and Purification Technology

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“…When this thiocarbamate herbicide is applied to the flooded paddies, it dissipates into the environment largely through volatilization. However, (photo)chemical and microbiological molinate transformation also occurs (28), resulting in accumulation of oxidized metabolites, such as oxomolinate and molinate sulfoxide (11,13), which have increased toxicity (5). The only biological system described so far as being able to mineralize molinate and use the herbicide as the sole source of carbon, energy, and nitrogen is a five-membered bacterial mixed culture (2,6).…”

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confidence: 99%

Gulosibacter molinativorax ON4 ^T Molinate Hydrolase, a Novel Cobalt-Dependent Amidohydrolase

et al. 2011

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A new pathway of molinate mineralization has recently been described. Among the five members of the mixed culture able to promote such a process, Gulosibacter molinativorax ON4 T has been observed to promote the initial breakdown of the herbicide into ethanethiol and azepane-1-carboxylate. In the current study, the gene encoding the enzyme responsible for molinate hydrolysis was identified and heterologously expressed, and the resultant active protein was purified and characterized. Nucleotide sequence analysis revealed that the gene encodes a 465-amino-acid protein of the metal-dependent hydrolase A subfamily of the amidohydrolase superfamily with a predicted molecular mass of 50.9 kDa. Molinate hydrolase shares the highest amino acid sequence identity (48 to 50%) with phenylurea hydrolases of Arthrobacter globiformis and Mycobacterium brisbanense. However, in contrast to previously described members of the metal-dependent hydrolase A subfamily, molinate hydrolase contains cobalt as the only active-site metal.Molinate is a herbicide which is extensively applied to rice fields worldwide. When this thiocarbamate herbicide is applied to the flooded paddies, it dissipates into the environment largely through volatilization. However, (photo)chemical and microbiological molinate transformation also occurs (28), resulting in accumulation of oxidized metabolites, such as oxomolinate and molinate sulfoxide (11, 13), which have increased toxicity (5). The only biological system described so far as being able to mineralize molinate and use the herbicide as the sole source of carbon, energy, and nitrogen is a five-membered bacterial mixed culture (2, 6). Among the five community members, Gulosibacter molinativorax ON4 T (gen. nov., sp. nov.), the only representative of this genus thus far (21), is responsible for the initial breakdown of molinate. In contrast to previously described molinate transformation reactions (13), G. molinativorax ON4T cleaves the thioester bond of molinate, releasing ethanethiol and azepane-1-carboxylate (ACA) (Fig. 1) (1). While this hydrolysis proceeds in the absence of oxygen, the further metabolism and mineralization of ACA by G. molinativorax ON4 T necessitate oxygen. Ethanethiol is not transformed by this organism but is spontaneously oxidized to diethyl disulfide. At molinate concentrations of Ͼ2 mM, the accumulating sulfur compounds are toxic for G. molinativorax ON4T and molinate mineralization is achieved only when other mixed-culture members able to degrade the sulfurcontaining metabolites are present (1, 2).In the present study, the molinate hydrolase (MolA) from G. molinativorax ON4T responsible for the key step of molinate breakdown was purified and characterized. The encoding gene was identified and expressed in Escherichia coli. This enzyme belongs to the metal-dependent hydrolase A subfamily of the amidohydrolase superfamily; however, in contrast to previously characterized members, it contains cobalt as a cofactor. To the best of our knowledge, this is the first description of an...

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“…Methyl bromide, trifluralin, carbaryl, and captan are already classified as toxic air contaminants in California pursuant to section 14021(b) of the Food and Agricultural Code (39). Nonoccupational exposures to molinate are suggested to exceed safety margins (40). Methyl bromide, chlorothalonil, and molinate have been detected in ambient air of agricultural communities in California (27).…”

Section: Discussionmentioning

confidence: 99%

Agricultural Pesticide Use in California: Pesticide Prioritization, Use Densities, and Population Distributions for a Childhood Cancer Study

Gunier¹,

Harnly²,

Reynolds³

et al. 2001

Environmental Health Perspectives

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Several studies have suggested an association between childhood cancer and pesticide exposure. California leads the nation in agricultural pesticide use. A mandatory reporting system for all agricultural pesticide use in the state provides information on the active ingredient, amount used, and location. We calculated pesticide use density to quantify agricultural pesticide use in California block groups for a childhood cancer study. Pesticides with similar toxicologic properties (probable carcinogens, possible carcinogens, genotoxic compounds, and developmental or reproductive toxicants) were grouped together for this analysis. To prioritize pesticides, we weighted pesticide use by the carcinogenic and exposure potential of each compound. The topranking individual pesticides were propargite, methyl bromide, and trifluralin. We used a geographic information system to calculate pesticide use density in pounds per square mile of total land area for all United States census-block groups in the state. Most block groups (77%) averaged less than 1 pound per square mile of use for 1991-1994 for pesticides classified as probable human carcinogens. However, at the high end of use density (> 90th percentile), there were 493 block groups with more than 569 pounds per square mile. Approximately 170,000 children under 15 years of age were living in these block groups in 1990. The distribution of agricultural pesticide use and number of potentially exposed children suggests that pesticide use density would be of value for a study of childhood cancer.

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Characterization of Risks Associated with the Use of Molinate

Cited by 41 publications

References 23 publications

Removal of organic contaminants from soils by an electrokinetic process: The case of molinate and bentazone. Experimental and modeling

Removal of organic contaminants from soils by an electrokinetic process: The case of molinate and bentazone. Experimental and modeling

Gulosibacter molinativorax ON4 ^T Molinate Hydrolase, a Novel Cobalt-Dependent Amidohydrolase

Agricultural Pesticide Use in California: Pesticide Prioritization, Use Densities, and Population Distributions for a Childhood Cancer Study

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Characterization of Risks Associated with the Use of Molinate

Cited by 41 publications

References 23 publications

Removal of organic contaminants from soils by an electrokinetic process: The case of molinate and bentazone. Experimental and modeling

Removal of organic contaminants from soils by an electrokinetic process: The case of molinate and bentazone. Experimental and modeling

Gulosibacter molinativorax ON4 T Molinate Hydrolase, a Novel Cobalt-Dependent Amidohydrolase

Agricultural Pesticide Use in California: Pesticide Prioritization, Use Densities, and Population Distributions for a Childhood Cancer Study

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Gulosibacter molinativorax ON4 ^T Molinate Hydrolase, a Novel Cobalt-Dependent Amidohydrolase