Deethylsimazine: bacterial dechlorination, deamination, and complete degradation

Cook, Alasdair M.; Hütter, Ralf

doi:10.1021/jf00123a040

Cited by 80 publications

(62 citation statements)

References 21 publications

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“…No accumulation of OEAT formed from CEAT was found in the incubation medium, presumably because of its deamination to OOET as shown previously with R. corallinus (8). We did observe the formation of OEAT from R. corallinus and from Rhodococcus sp.…”

Section: Identification Of Ceat Metabolitessupporting

confidence: 86%

“…It is not clear if this observation is related to the fact that, unlike R. corallinus, Rhodococcus strain TE3 cannot utilize OOOT as a source of nitrogen for growth. The reported deaminase activity toward AAAT associated with s-triazine hydrolase (8,23) was not detectable in the Rhodococcus recombinants, which did not utilize AAAT as a source of nitrogen for growth.…”

Section: Discussionmentioning

confidence: 96%

“…Cook and Hutter (5,8) isolated and characterized an isolate of Rhodococcus corallinus that dechlorinates and deaminates the dealkylated s-triazine compounds CEAT and CIAT but not atrazine. The enzyme, named s-triazine hydrolase and encoded by the trzA gene, has been purified (23).…”

mentioning

confidence: 99%

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Cloning and expression of the s-triazine hydrolase gene (trzA) from Rhodococcus corallinus and development of Rhodococcus recombinant strains capable of dealkylating and dechlorinating the herbicide atrazine

et al. 1995

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We used degenerate oligodeoxyribonucleotides derived from the N-terminal sequence of the s-triazine hydrolase from Rhodococcus corallinus NRRL B-15444R in an amplification reaction to isolate a DNA segment containing a 57-bp fragment from the trzA gene. By using the nucleotide sequence of this fragment, a nondegenerate oligodeoxyribonucleotide was synthesized and used to screen a genomic library of R. corallinus DNA for fragments containing trzA. A 5.3-kb PstI fragment containing trzA was cloned, and the nucleotide sequence of a 2,450-bp region containing trzA was determined. No trzA expression was detected in Escherichia coli or several other gram-negative bacteria. The trzA gene was subcloned into a Rhodococcus-E. coli shuttle vector, pBS305, and transformed into several Rhodococcus strains. Expression of trzA was demonstrated in all Rhodococcus transformants. Rhodococcus sp. strain TE1, which possesses the catabolic gene (atrA) for the N-dealkylation of the herbicides atrazine and simazine, was able to dechlorinate the dealkylated metabolites of atrazine and simazine when carrying the trzA gene on a plasmid. A plasmid carrying both atrA and trzA was constructed and transformed into three atrA-and trzA-deficient Rhodococcus strains. Both genes were expressed in the transformants. The s-triazine hydrolase activity of the recombinant strains carrying the trzA plasmid were compared with that of the R. corallinus strain from which it was derived.The s-triazine herbicides have been used in a variety of weed control programs with major crops. Atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine) is one of the most heavily used herbicides in North America (21). The detection of atrazine in groundwater and surface water has prompted some environmental concerns (1, 14). There has been considerable interest in finding microbial activities that might be used to degrade atrazine and other s-triazine compounds in herbicide wastes and contaminated soils (6,7,12,16,24). Several microorganisms that can metabolize atrazine have been isolated during the last few years (2,3,17,18,25,33). We recently reported that Rhodococcus sp. strain TE1 can degrade atrazine efficiently to produce the dealkylated metabolites deisopropylatrazine (2-chloro-4-ethylamino-6-amino-s-triazine [CEAT]) and deethylatrazine (2-chloro-4-amino-6-isopropylamino-s-triazine [CIAT]) and that this catabolic function was associated with an indigenous 77-kb plasmid in this bacterium (4, 28). Two recently reported Pseudomonas isolates (18, 33) degrade atrazine efficiently but by different pathways.Cook and Hutter (5, 8) isolated and characterized an isolate of Rhodococcus corallinus that dechlorinates and deaminates the dealkylated s-triazine compounds CEAT and CIAT but not atrazine. The enzyme, named s-triazine hydrolase and encoded by the trzA gene, has been purified (23). The combination of the catabolic activities of both Rhodococcus sp. strain TE1 and R. corallinus would result in dealkylation and dechlorination of atrazine.We have been involved in...

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Section: Identification Of Ceat Metabolitessupporting

confidence: 86%

Section: Discussionmentioning

confidence: 96%

See 1 more Smart Citation

Cloning and expression of the s-triazine hydrolase gene (trzA) from Rhodococcus corallinus and development of Rhodococcus recombinant strains capable of dealkylating and dechlorinating the herbicide atrazine

et al. 1995

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“…strain A (NRRL B-12227) was isolated as a melamine-utilizing bacterium from municipal sewage collected in Switzerland (Cook and Hütter 1981;Cook 1987) and was later reclassified as Acidovorax citrulli (Seffernick et al 2002;Schaad et al 2008). Another melamine-degrading isolate, Rhodococcus corallinus strain 11 (NRRL B-15444R), was obtained from soils that had been experimentally exposed to s-triazine herbicides for a long time (Cook and Hütter 1984;Cook 1987). R. corallinus was originally considered to be a junior synonym of Rhodococcus rubropertinctus in a DNA homology study (Mordarski et al 1980), and has since been reclassified as Gordonia rubripertincta (Stackebrandt et al 1988;Euzeby 1998).…”

Section: Introductionmentioning

confidence: 99%

Biodegradation of melamine and its hydroxy derivatives by a bacterial consortium containing a novel Nocardioides species

Takagi

Fujii

Yamazaki

et al. 2011

Appl Microbiol Biotechnol

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Melamine has recently been recognized as a food contaminant with adverse human health effects. Melamine contamination in some crops arises from soil and water pollution from various causes. To remove melamine from the polluted environment, a novel bacterium, Nocardioides sp. strain ATD6, capable of degrading melamine was enriched and isolated from a paddy soil sample. The enrichment culture was performed by the soil-charcoal perfusion method in the presence of triazine-degrading bacteria previously obtained. Strain ATD6 degraded melamine and accumulated cyanuric acid and ammonium, via the intermediates ammeline and ammelide. No gene known to encode for triazine-degrading enzymes was detected in strain ATD6. A mixed culture of strain ATD6 and a simazine-degrading Methyloversatilis sp. strain CDB21 completely degraded melamine, but the degradation rate of cyanuric acid was slow. The degradation of melamine and its catabolites by the mixed culture was greatly enhanced by including Bradyrhizobium japonicum strain CSB1 in the inoculum and adding ethanol to the culture medium. The melamine-degrading consortium consisting of strains ATD6, CDB21, and CSB1 appears to be potentially safer than other known melamine-degrading bacteria for the bioremediation of farmland and other contaminated sites, as no known pathogens were included in the consortium.

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“…The amount of 14 CO 2 produced by mineralization of cyanuric acid would have increased with a longer incubation. It has been reported that a cyanuric acid-mineralizing population frequently occurs in natural environments 3,5,6) . The ring cleavage path- way of cyanuric acid has been also examined 4) .…”

Section: Mineralization Of Intermediary Metabolite Cyanuric Acidmentioning

confidence: 99%

Role and Behavior of Benthic Microbes Able to Degrade Herbicide Atrazine in Naturally Derived Water/sediment Microcosm.

et al. 2002

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In a simple laboratory microcosm constituted of riverbed sediment and its associated water, rapid degradation of herbicide atrazine mainly to cyanuric acid occurred through microbial degradation. To elucidate the role and behavior of microbes involved in atrazine degradation, comparative microcosms constituted of different sediment/water conditions and constitutions were employed. Fluorescence microscopic observation and direct bacterial count by DAPI (4',6-diamidino-2-phenylindole)-staining and CFU (colony forming unit) count by the plate method were also conducted to supplement the comparative study. As a result, planktonic microbes in the aqueous phase appeared not to be responsible for the initial degradation of atrazine, at least during the present experimental period of 70 days. The sediment was found to be important as a source of degrading microbes. However, once the degradation was initiated, the degrading activity in the aqueous phase was maintained without the sediment. Although CFU in aqueous phase increased with time, this increase in cell number seemed not to reflect the degrading activity. Large, glittering and whole particles, supposed to be microbial cells, were observed by DAPI-staining in the aqueous phase under a microscopic field only when active atrazine-degradation occurred. Therefore, they might be involved in the degrading activity.

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Deethylsimazine: bacterial dechlorination, deamination, and complete degradation

Cited by 80 publications

References 21 publications

Cloning and expression of the s-triazine hydrolase gene (trzA) from Rhodococcus corallinus and development of Rhodococcus recombinant strains capable of dealkylating and dechlorinating the herbicide atrazine

Cloning and expression of the s-triazine hydrolase gene (trzA) from Rhodococcus corallinus and development of Rhodococcus recombinant strains capable of dealkylating and dechlorinating the herbicide atrazine

Biodegradation of melamine and its hydroxy derivatives by a bacterial consortium containing a novel Nocardioides species

Role and Behavior of Benthic Microbes Able to Degrade Herbicide Atrazine in Naturally Derived Water/sediment Microcosm.

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