Degradation of Substituted Phenylurea Herbicides by
            <i>Arthrobacter globiformis</i>
            Strain D47 and Characterization of a Plasmid-Associated Hydrolase Gene,
            <i>puhA</i>

Turnbull, Gillian A.; Ousley, Margaret; Walker, A.; Shaw, E.D.; Morgan, J. Alun W.

doi:10.1128/aem.67.5.2270-2275.2001

Cited by 106 publications

(111 citation statements)

References 35 publications

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“…4 is derived from biodegradation data on Arthrobacter strains that have been generated over the past 50 years. For example, diuron, glyphosate, phenmediphan, carbaryl, monocrotophos, iprodione, EPTC (sethyl dipropylthiocarbamate), and natural-product toxins, such as nicotine and (Ϫ)-synephrine, are metabolized to generate amines, amides, and guanidines (3,5,29,30,77). The initiating metabolism in all of these examples is encoded by plasmid genes.…”

Section: Sp Extended To Other Pesticidesmentioning

confidence: 99%

Evolution of Catabolic Pathways: Genomic Insights into Microbial s -Triazine Metabolism

Shapir

Mongodin²,

Sadowsky

et al. 2007

J Bacteriol

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Section: Sp Extended To Other Pesticidesmentioning

confidence: 99%

Evolution of Catabolic Pathways: Genomic Insights into Microbial s -Triazine Metabolism

Shapir

Mongodin²,

Sadowsky

et al. 2007

J Bacteriol

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“…At the Deep Slade site, various bacteria capable of degrading IPU have been isolated (8,19,21). However, the relative importance of each in the degradation of IPU in situ is unclear.IPU-degrading isolates from Deep Slade field include an Arthrobacter sp., which degrades phenyl-ureas to their aniline derivatives by hydrolysis of the urea side chain at the carbonyl group (8,24,25), and a Sphingomonas sp. (strain SRS2), which degrades IPU by sequential N-demethylation of the urea side chain followed by mineralization of the phenyl-urea structure (21).…”

mentioning

confidence: 99%

In-Field Spatial Variability in the Degradation of the Phenyl-Urea Herbicide Isoproturon Is the Result of Interactions between Degradative Sphingomonas spp. and Soil pH

Bending¹,

Lincoln²,

Sørensen

et al. 2003

Appl Environ Microbiol

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147

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Substantial spatial variability in the degradation rate of the phenyl-urea herbicide isoproturon (IPU) [3-(4-isopropylphenyl)-1,1-dimethylurea] has been shown to occur within agricultural fields, with implications for the longevity of the compound in the soil, and its movement to ground-and surface water. The microbial mechanisms underlying such spatial variability in degradation rate were investigated at Deep Slade field in Warwickshire, United Kingdom. Most-probable-number analysis showed that rapid degradation of IPU was associated with proliferation of IPU-degrading organisms. Slow degradation of IPU was linked to either a delay in the proliferation of IPU-degrading organisms or apparent cometabolic degradation. Using enrichment techniques, an IPU-degrading bacterial culture (designated strain F35) was isolated from fast-degrading soil, and partial 16S rRNA sequencing placed it within the Sphingomonas group. Denaturing gradient gel electrophoresis (DGGE) of PCR-amplified bacterial community 16S rRNA revealed two bands that increased in intensity in soil during growth-linked metabolism of IPU, and sequencing of the excised bands showed high sequence homology to the Sphingomonas group. However, while F35 was not closely related to either DGGE band, one of the DGGE bands showed 100% partial 16S rRNA sequence homology to an IPU-degrading Sphingomonas sp. (strain SRS2) isolated from Deep Slade field in an earlier study. Experiments with strains SRS2 and F35 in soil and liquid culture showed that the isolates had a narrow pH optimum (7 to 7.5) for metabolism of IPU. The pH requirements of IPU-degrading strains of Sphingomonas spp. could largely account for the spatial variation of IPU degradation rates across the field.Concern about the environmental impact of pesticides most frequently arises from their ability to leach from soil and contaminate water resources. The phenyl-urea herbicides are of particular significance in this respect, since several members of the group, including isoproturon (IPU) [3-(4-isopropylphenyl)-1,1-dimethylurea] and diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea] are degraded slowly in soil and are susceptible to leaching. As a result, IPU and diuron are frequently detected as contaminants of agricultural catchments in Europe (23).Studies of the fate of IPU in agricultural fields on contrasting soil types have revealed considerable spatial variability in degradation rates across fields (2,26,27). At two such sites in the United Kingdom, Deep Slade field in Warwickshire and Brimstone farm in Oxfordshire, IPU half-life in soil was found to vary between 6 and 30 days, with degradation rate linked to soil pH. Further studies by Bending et al. (3) demonstrated that soil pH controlled the ease of induction of growth-linked metabolism, with slow degradation rates at lower soil pH linked to apparent cometabolic degradation of the compound. At the Deep Slade site, various bacteria capable of degrading IPU have been isolated (8,19,21). However, the relative importance of each in the degradation...

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“…Formation of p-nitrophenol was measured by optical absorbance of the samples at 420 nm. To determine the presence of a chlorpyrifos-degrading gene or plasmid, standard methods were used as described previously (36,38). Substrate range.…”

mentioning

confidence: 99%

Biodegradation of Chlorpyrifos by Enterobacter Strain B-14 and Its Use in Bioremediation of Contaminated Soils

Singh

Walker

Morgan

et al. 2004

Appl Environ Microbiol

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397

212

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Six chlorpyrifos-degrading bacteria were isolated from an Australian soil and compared by biochemical and molecular methods. The isolates were indistinguishable, and one (strain B-14) was selected for further analysis. This strain showed greatest similarity to members of the order Enterobacteriales and was closest to members of the Enterobacter asburiae group. The ability of the strain to mineralize chlorpyrifos was investigated under different culture conditions, and the strain utilized chlorpyrifos as the sole source of carbon and phosphorus. Studies with ring or uniformly labeled [14 C]chlorpyrifos in liquid culture demonstrated that the isolate hydrolyzed chlorpyrifos to diethylthiophospshate (DETP) and 3, 5, 6-trichloro-2-pyridinol, and utilized DETP for growth and energy. The isolate was found to possess mono-and diphosphatase activities along with a phosphotriesterase activity. Addition of other sources of carbon (glucose and succinate) resulted in slowing down of the initial rate of degradation of chlorpyrifos. The isolate degraded the DETP-containing organophosphates parathion, diazinon, coumaphos, and isazofos when provided as the sole source of carbon and phosphorus, but not fenamiphos, fonofos, ethoprop, and cadusafos, which have different side chains. Studies of the molecular basis of degradation suggested that the degrading ability could be polygenic and chromosome based. Further studies revealed that the strain possessed a novel phosphotriesterase enzyme system, as the gene coding for this enzyme had a different sequence from the widely studied organophosphate-degrading gene (opd). The addition of strain B-14 (10 6 cells g ؊1 ) to soil with a low indigenous population of chlorpyrifosdegrading bacteria treated with 35 mg of chlorpyrifos kg ؊1 resulted in a higher degradation rate than was observed in noninoculated soils. These results highlight the potential of this bacterium to be used in the cleanup of contaminated pesticide waste in the environment.

show abstract

Degradation of Substituted Phenylurea Herbicides by Arthrobacter globiformis Strain D47 and Characterization of a Plasmid-Associated Hydrolase Gene, puhA

Cited by 106 publications

References 35 publications

Evolution of Catabolic Pathways: Genomic Insights into Microbial s -Triazine Metabolism

Evolution of Catabolic Pathways: Genomic Insights into Microbial s -Triazine Metabolism

In-Field Spatial Variability in the Degradation of the Phenyl-Urea Herbicide Isoproturon Is the Result of Interactions between Degradative Sphingomonas spp. and Soil pH

Biodegradation of Chlorpyrifos by Enterobacter Strain B-14 and Its Use in Bioremediation of Contaminated Soils

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