Isolation and characterisation of a bacterial strain degrading the herbicide sulcotrione from an agricultural soil.
ABSTRACT The dissipation kinetics of the herbicide sulcotrione sprayed 4 times on a French soil was studied using a laboratory microcosm approach. An advanced cultivation-based method was then used to isolate the bacteria responsible for biotransformation of sulcotrione. Chromatographic methods were employed as complementary tools to define its metabolic pathway.
Soil microflora was able quickly to biotransform the herbicide (DT(50) ≈ 8 days). 2-Chloro-4-mesylbenzoic acid, one of its main metabolites, was clearly detected. However, no accelerated biodegradation process was observed. Eight pure sulcotrione-resistant strains were isolated, but only one (1OP) was capable of degrading this herbicide with a relatively high efficiency and to use it as a sole source of carbon and energy. In parallel, another sulcotrione-resistant strain (1TRANS) was shown to be incapable of degrading the herbicide. Amplified ribosomal restriction analysis (ARDRA) and repetitive extragenic palendromic PCR genomic (REP-PCR) fingerprinting of strains 1OP and 1TRANS gave indistinguishable profiles.
Sequencing and aligning analysis of 16S rDNA genes of each pure strain revealed identical sequences and a close phylogenetic relationship (99% sequence identity) to Pseudomonas putida. Such physiological and genetic properties of 1OP to metabolise sulcotrione were probably governed by mobile genetic elements in the genome of the bacteria.
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ABSTRACT: Dissipation kinetics of mesotrione, a new triketone herbicide, sprayed on soil from Limagne (Puy-de-Dôme, France) showed that the soil microflora were able to biotransform it.Bacteria from this soil were cultured in mineral salt solution supplemented with mesotrione as sole source of carbon for the isolation of mesotrione-degrading bacteria. The bacterial community structure of the enrichment cultures was analyzed by temporal temperature gradient gel electrophoresis (TTGE). The TTGE fingerprints revealed that mesotrione had an impact on bacterial community structure only at its highest concentrations and showed mesotrione-sensitive and mesotrione-adapted strains. Two adapted strains, identified as Bacillus sp. and Arthrobacter sp., were isolated by colony hybridization methods.Biodegradation assays showed that only the Bacillus sp. strain was able to completely and rapidly biotransform mesotrione. Among several metabolites formed, 2-amino-4-methylsulfonylbenzoic acid (AMBA) accumulated in the medium. Although sulcotrione has a chemical structure closely resembling that of mesotrione, the isolates were unable to degrade it.Environmental pollution (Barking, Essex: 1987) 02/2009; 157(4):1195-1201. · 3.43 Impact Factor
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ABSTRACT: The behaviour of sulcotrione, a recently introduced triketone herbicide, in various soil types was studied under laboratory conditions. In particular, degradation and sorption processes were examined on Ghent and Perpignan soils. Kinetics showed that the degradation of sulcotrione was influenced by biotic and/or abiotic factors. Half-lives ranged between 45 and 65 days. Among the degradation compounds identified were 1,3-cyclohexanedione (CHD) and 2-chloro-4-mesyl benzoic acid (CMBA), previously described as hydrolysis products, and, under special conditions, a derivative of phenylheptanoic acid (PHD). This new degradation product suggested that sulcotrione could follow two possible pathways in the soil, as in water. During the sorption study, a moderate retention of sulcotrione and CMBA relative to CHD and PHD, which were highly adsorbed whatever the soil type, was reported. Experiments carried out under the same conditions for sulcotrione and mesotrione, another triketone herbicide recommended in maize culture, made it possible to compare the two triketones and to conclude that they exhibited relatively similar behaviour in the soil, i.e. that their leaching potential needs to be properly addressed and risks evaluated.Pest Management Science 02/2008; 64(1):86-93. · 2.59 Impact Factor
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ABSTRACT: A rapid procedure for the identification of cultured Mycobacterium isolates, based on the combination of enzymatic amplification and restriction analysis, is described. The 16S rRNA genes (rDNA) of 99 strains belonging to 18 different species of the genus Mycobacterium were enzymatically amplified. Amplified rDNA restriction analysis with the enzymes CfoI, MboI, and RsaI was carried out. The combination of the amplified rDNA restriction analysis patterns obtained after restriction with CfoI and MboI enabled differentiation between Mycobacterium asiaticum (number of strains = 4), M. avium (n = 22), M. chelonae (n = 5), M. flavescens (n = 1), M. fortuitum (n = 6), M. gordonae (n = 6), M. intracellulare (n = 13), M. marinum (n = 7), M. nonchromogenicum (n = 1), M. simiae (n = 5), M. terrae (n = 5), the M. tuberculosis complex (n = 11), and 2 of 4 strains of M. xenopi. Further restriction with RsaI was necessary to differentiate between the species M. kansasii (n = 5), M. scrofulaceum (n = 4), and the 2 other M. xenopi strains. The M. avium-M. intracellulare complex was characterized by a specific MboI pattern, and M. avium and M. intracellulare strains could further be differentiated by restriction with CfoI. The whole procedure, including sample preparation prior to the polymerase chain reaction, can be carried out within 8 h, starting from a pure culture.Journal of Clinical Microbiology 09/1993; 31(8):2061-5. · 4.07 Impact Factor