Klebsiella planticola strain DSZ mineralizes simazine: physiological adaptations involved in the process

Sánchez, Mariela; Garbi, Carlos; Martínez‐Álvarez, Roberto; Ortíz, L.; Allende, J.L.; Martín, Margarita

doi:10.1007/s00253-004-1735-y

Cited by 25 publications

(12 citation statements)

References 35 publications

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“…Taken together, these experiments are consistent with the conclusion that cyanuric acid metabolism proceeds through allophanate exclusively in all the strains tested. This is important to establish because almost all papers discussing s-triazine ring degradation over the last 20 years have presumed that urea is the pathway intermediate in all bacteria isolated for their ability to mineralize melamine, ammeline, and s-triazine herbicides (1,6,12,30,34,36). The hydrolysis of biuret at the subterminal carbon-nitrogen bond is chemically plausible, so it is certainly possible that some bacteria might hydrolyze biuret to yield urea.…”

Section: Discussionmentioning

confidence: 99%

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Allophanate Hydrolase, Not Urease, Functions in Bacterial Cyanuric Acid Metabolism

Cheng

Shapir

Sadowsky

et al. 2005

Appl Environ Microbiol

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Growth substrates containing an s-triazine ring are typically metabolized by bacteria to liberate 3 mol of ammonia via the intermediate cyanuric acid. Over a 25-year period, a number of original research papers and reviews have stated that cyanuric acid is metabolized in two steps to the 2-nitrogen intermediate urea. In the present study, allophanate, not urea, was shown to be the 2-nitrogen intermediate in cyanuric acid metabolism in all the bacteria examined. Six different experimental results supported this conclusion: (i) synthetic allophanate was shown to readily decarboxylate to form urea under acidic extraction and chromatography conditions used in previous studies; (ii) alkaline extraction methods were used to stabilize and detect allophanate in bacteria actively metabolizing cyanuric acid; (iii) the kinetic course of allophanate formation and disappearance was consistent with its being an intermediate in cyanuric acid metabolism, and no urea was observed in those experiments; (iv) protein extracts from cells grown on cyanuric acid contained allophanate hydrolase activity; (v) genes encoding the enzymes AtzE and AtzF, which produce and hydrolyze allophanate, respectively, were found in several cyanuric acidmetabolizing bacteria; and (vi) TrzF, an AtzF homolog found in Enterobacter cloacae strain 99, was cloned, expressed in Escherichia coli, and shown to have allophanate hydrolase activity. In addition, we have observed that there are a large number of genes homologous to atzF and trzF distributed in phylogenetically distinct bacteria. In total, the data indicate that s-triazine metabolism in a broad class of bacteria proceeds through allophanate via allophanate hydrolase, rather than through urea using urease.

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Section: Discussionmentioning

confidence: 99%

“…In subsequent years, the cyanuric acid pathway shown in Fig. 1 (upper pathway) has been attributed to other bacteria that grow on melamine or s-triazine herbicides (12,30,34,36).…”

mentioning

confidence: 99%

Allophanate Hydrolase, Not Urease, Functions in Bacterial Cyanuric Acid Metabolism

Cheng

Shapir

Sadowsky

et al. 2005

Appl Environ Microbiol

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“…A study by Balangué et al [53] with E. coli HB101 strain demonstrated that the toxicity of 2,4-D could reduce the fluidity of bacterial membrane, and consequently alter MDA results, as a system-wide response against ROS. Sánchez et al [56] also reported similar findings, where the strain Klebsiella planticola DSZ, when in contact with ethanol or the herbicide simazine, exhibited a decrease in the saturation of membrane lipids, altering the rate of selective permeability, possibly as a defense system.…”

Section: Resultsmentioning

confidence: 64%

Mechanisms of Tolerance and High Degradation Capacity of the Herbicide Mesotrione by Escherichia coli Strain DH5-α

et al. 2014

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The intensive use of agrochemicals has played an important role in increasing agricultural production. One of the impacts of agrochemical use has been changes in population structure of soil microbiota. The aim of this work was to analyze the adaptive strategies that bacteria use to overcome oxidative stress caused by mesotrione, which inhibits 4-hydroxyphenylpyruvate dioxygenase. We also examined antioxidative stress systems, saturation changes of lipid membranes, and the capacity of bacteria to degrade mesotrione. Escherichia coli DH5-á was chosen as a non-environmental strain, which is already a model bacterium for studying metabolism and adaptation. The results showed that this bacterium was able to tolerate high doses of the herbicide (10× field rate), and completely degraded mesotrione after 3 h of exposure, as determined by a High Performance Liquid Chromatography. Growth rates in the presence of mesotrione were lower than in the control, prior to the period of degradation, showing toxic effects of this herbicide on bacterial cells. Changes in the saturation of the membrane lipids reduced the damage caused by reactive oxygen species and possibly hindered the entry of xenobiotics in the cell, while activating glutathione-S-transferase enzyme in the antioxidant system and in the metabolizing process of the herbicide. Considering that E. coli DH5-α is a non-environmental strain and it had no previous contact with mesotrione, the defense system found in this strain could be considered non-specific. This bacterium system response may be a general adaptation mechanism by which bacterial strains resist to damage from the presence of herbicides in agricultural soils.

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“…The activity of microorganisms which modifies herbicides activity can proceed various ways which hence lead either to decreasing or increasing their toxicity. Microorganisms can use herbicides as food or energy source or exploit the product of herbicides degradation as biosynthesis of humic acids precursors (Gebendinger and Radosevich 1999; Sánchez et al 2005). …”

Section: Introductionmentioning

confidence: 99%

“…Biotechnological methods allow to recreate natural environment conditions, and they are less expensive and quite often easier as well as more effective (Sánchez et al 2005). As with petroleum derivatives, there is the possibility of biological utilization of hazardous pesticides on half-technical scale.…”

Section: Introductionmentioning

confidence: 99%

Screening of Microorganisms for Biodegradation of Simazine Pollution (Obsolete Pesticide Azotop 50 WP)

Błaszak

Pełech

Graczyk

2011

Water Air Soil Pollut

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The capability of environmental microorganisms to biodegrade simazine—an active substance of 2-chloro-s-triazine herbicides (pesticide waste since 2007)—was assessed. An enormous metabolic potential of microorganisms impels to explore the possibilities of using them as an alternative way for thermal and chemical methods of utilization. First, the biotope rich in microorganisms resistant to simazine was examined. Only the higher dose of simazine (100 mg/l) had an actual influence on quantity of bacteria and environmental fungi incubated on substrate with simazine. Most simazine-resistant bacteria populated activated sludge and biohumus (vermicompost); the biggest strain of resistant fungi was found in floral soil and risosphere soil of maize. Compost and biohumus were the sources of microorganisms which biodegraded simazine, though either of them was the dominant considering the quantity of simazine-resistant microorganisms. In both cases of periodic culture (microorganisms from biohumus and compost), nearly 100% of simazine (50 mg/l) was degraded (within 8 days). After the repeated enrichment culture with simazine, the rate of its degradation highly accelerated, and just after 24 h, the significant decrease of simazine (20% in compost and 80% in biohumus) was noted. Although a dozen attempts of isolating various strains responsible for biodegradation of simazine from compost and biohumus were performed, only the strain identified as Arthrobacter urefaciens (NC) was obtained, and it biodegraded simazine with almost 100% efficiency (within 4 days).

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Klebsiella planticola strain DSZ mineralizes simazine: physiological adaptations involved in the process

Cited by 25 publications

References 35 publications

Allophanate Hydrolase, Not Urease, Functions in Bacterial Cyanuric Acid Metabolism

Allophanate Hydrolase, Not Urease, Functions in Bacterial Cyanuric Acid Metabolism

Mechanisms of Tolerance and High Degradation Capacity of the Herbicide Mesotrione by Escherichia coli Strain DH5-α

Screening of Microorganisms for Biodegradation of Simazine Pollution (Obsolete Pesticide Azotop 50 WP)

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