The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform

Michael J. Lydy - One of the best experts on this subject based on the ideXlab platform.

  • impact of Atrazine on organophosphate insecticide toxicity
    Environmental Toxicology and Chemistry, 2000
    Co-Authors: J. B. Belden, Michael J. Lydy
    Abstract:

    Acute toxicity of selected organophosphorus insecticides (OPs; chlorpyrifos, methyl parathion, diazinon, and malathion) was determined for individual OPs and binary combinations of the OPs with Atrazine to larvae of the midge Chironomus tentans. Atrazine individually was not acutely toxic even at high concentrations (10,000 mg/L); however, the presence of Atrazine at much lower concentrations (40-200 mg/L) increased the toxicity of chlorpyrifos, methyl parathion, and diazinon. Atrazine did not increase the toxicity of malathion. Possible mechanisms for the synergistic toxicity found between Atrazine and chlorpyrifos were investigated, including increased uptake rate and increased biotransformation into a more toxic metabolite. Although the uptake rate was increased by more than 40%, the resulting increase in toxicity would be minimal as compared to the 400% decrease estimated to occur in EC50 values for the same Atrazine exposure (200 mg/L). Body residue analysis of midges exposed in vivo to Atrazine and chlorpyrifos mixtures for 96 h indicated that a larger amount of metabolites was generated in Atrazine treatments as compared to controls. Additionally, in vitro assays of microsomal proteins obtained from treated and control midges indicated that an increase in toxic metabolite (chlorpyrifos-O-analog) was generated in Atrazine-treated midges. Therefore, the increase in toxicity is thought to be due to an increase in biotransformation rates of the OPs, resulting in more O-analog within the organism. Keywords—Atrazine Organophosphate insecticides Mixtures Synergism Biotransformation

  • Impact of Atrazine on organophosphate insecticide toxicity
    Environmental Toxicology and Chemistry, 2000
    Co-Authors: J. B. Belden, Michael J. Lydy
    Abstract:

    Acute toxicity of selected organophosphorus insecticides (OPs; chlorpyrifos, methyl parathion, diazinon, and malathion) was determined for individual OPs and binary combinations of the OPs with Atrazine to larvae of the midge Chironomus tentans. Atrazine individually was not acutely toxic even at high concentrations (10,000 mg/L); however, the presence of Atrazine at much lower concentrations (40–200 mg/L) increased the toxicity of chlorpyrifos, methyl parathion, and diazinon. Atrazine did not increase the toxicity of malathion. Possible mechanisms for the synergistic toxicity found between Atrazine and chlorpyrifos were investigated, including increased uptake rate and increased biotransformation into a more toxic metabolite. Although the uptake rate was increased by more than 40%, the resulting increase in toxicity would be minimal as compared to the 400% decrease estimated to occur in EC50 values for the same Atrazine exposure (200 mg/L). Body residue analysis of midges exposed in vivo to Atrazine and chlorpyrifos mixtures for 96 h indicated that a larger amount of metabolites was generated in Atrazine treatments as compared to controls. Additionally, in vitro assays of microsomal proteins obtained from treated and control midges indicated that an increase in toxic metabolite (chlorpyrifos-O-analog) was generated in Atrazine-treated midges. Therefore, the increase in toxicity is thought to be due to an increase in biotransformation rates of the OPs, resulting in more O-analog within the organism

  • synergistic toxicity of Atrazine and organophosphate insecticides contravenes the response addition mixture model
    Environmental Toxicology and Chemistry, 1997
    Co-Authors: Pamela Papelindstrom, Michael J. Lydy
    Abstract:

    A toxic unit (TU) approach was used to test the response addition model for mixtures of pesticides with differing modes of action. Atrazine was tested in binary and ternary combinations with the organochlorine insecticide methoxychlor and organophosphate insecticide methyl-parathion. Atrazine was also tested in binary combinations with additional organophosphates. The TU for Atrazine was set slightly below its water solubility limits (TU = 20 ppm), which is well below its 96-h 50% effective concentration for the fourth instar of the midge, Chironomus tentans. In 96-h acute toxicity tests using C. tentans, Atrazine was found to produce synergistic (greater than additive) toxicity in a binary mixture with methyl-parathion. Less than additive toxicity was found for the combination of Atrazine with methoxychlor (likely due to the low TU assigned to Atrazine). The ternary combination of Atrazine + methyl-parathion + methoxychlor was found to be marginally synergistic. Results of toxicity tests with Atrazine in binary combinations with other organophosphates indicate more than additive toxicity for all compounds except mevinophos. Possible hypotheses are presented in an attempt to explain the noted synergistic relationship between Atrazine and various organophosphorous insecticides. These results suggest that the response addition model does not always accurately predict mixture toxicity for chemicals with differing modes of action.

Lawrence P Wackett - One of the best experts on this subject based on the ideXlab platform.

  • Biodegradation of Atrazine by three transgenic grasses and alfalfa expressing a modified bacterial Atrazine chlorohydrolase gene
    Transgenic Research, 2014
    Co-Authors: Andrew Vail, Lawrence P Wackett, Ping Wang, Hirotaka Uefuji, Deborah A. Samac, Carroll P. Vance, Michael J. Sadowsky
    Abstract:

    The widespread use of Atrazine and other s-triazine herbicides to control weeds in agricultural production fields has impacted surface and groundwater in the United States and elsewhere. We previously reported the cloning, sequencing, and expression of six genes involved in the Atrazine biodegradation pathway of Pseudomonas sp. strain ADP, which is initiated by atzA, encoding Atrazine chlorohydrolase. Here we explored the use of enhanced expression of a modified bacterial Atrazine chlorohydrolase, p-AtzA, in transgenic grasses (tall fescue, perennial ryegrass, and switchgrass) and the legume alfalfa for the biodegradation of Atrazine. Enhanced expression of p-AtzA was obtained by using combinations of the badnavirus promoter, the maize alcohol dehydrogenase first intron, and the maize ubiquitin promoter. For alfalfa, we used the first intron of the 5′-untranslated region tobacco alcohol dehydrogenase gene and the cassava vein mosaic virus promoter. Resistance of plants to Atrazine in agar-based and hydroponic growth assays was correlated with in vivo levels of gene expression and Atrazine degradation. The in planta expression of p-atzA enabled transgenic tall fescue to transform Atrazine into hydroxyAtrazine and other metabolites. Results of our studies highlight the potential use of transgenic plants for bioremediating Atrazine in the environment.

  • Biodegradation of Atrazine in transgenic plants expressing a modified bacterial Atrazine chlorohydrolase ( atzA ) gene
    Plant Biotechnology Journal, 2005
    Co-Authors: Lin Wang, Lawrence P Wackett, Deborah A. Samac, Carroll P. Vance, Nir Shapir, Neil E. Olszewski, Michael J. Sadowsky
    Abstract:

    Summary Atrazine is one of the most widely used herbicides in the USA. Atrazine chlorohydrolase (AtzA), the first enzyme in a six-step pathway leading to the mineralization of Atrazine in Gram-negative soil bacteria, catalyses the hydrolytic dechlorination and detoxification of Atrazine to hydroxyAtrazine. In this study, we investigated the potential use of transgenic plants expressing atzA to take up, dechlorinate and detoxify Atrazine. Alfalfa, Arabidopsis thaliana and tobacco were transformed with a modified bacterial atzA gene, p -atzA, under the control of the cassava vein mosaic virus promoter. All transgenic plant species actively expressed p -atzA and grew over a wide range of Atrazine concentrations. Thin layer chromatography analyses indicated that in planta expression of p -atzA resulted in the production of hydroxyAtrazine. Hydroponically grown transgenic tobacco and alfalfa dechlorinated Atrazine to hydroxyAtrazine in leaves, stems and roots. Moreover, p -atzA was found to be useful as a conditional-positive selection system to isolate alfalfa and Arabidopsis transformants following Agrobacterium -mediated transformation. Our work suggests that the in planta expression of p -atzA may be useful for the development of plants for the phytoremediation of Atrazine-contaminated soils and soil water, and as a marker gene to select for the integration of exogenous DNA into the plant genome.

  • Field-scale remediation of Atrazine-contaminated soil using recombinant Escherichia coli expressing Atrazine chlorohydrolase
    Environmental Microbiology, 2000
    Co-Authors: Lisa C. Strong, Hugh Mctavish, Michael J. Sadowsky, Lawrence P Wackett
    Abstract:

    We performed the first field-scale Atrazine remediation study in the United States using chemically killed, recombinant organisms. This field study compared biostimulation methods for enhancing Atrazine degradation with a novel bioaugmentation protocol using a killed and stabilized whole-cell suspension of recombinant Escherichia coli engineered to overproduce Atrazine chlorohyrolase, AtzA. AtzA dechlorinates Atrazine, producing non-toxic and non-phytotoxic hydroxyAtrazine. Soil contaminated by an accidental spill of Atrazine (up to 29 000 p.p.m.) supported significant populations of indigenous microorganisms capable of Atrazine catabolism. Laboratory experiments indicated that supplementing soil with carbon inhibited Atrazine biodegradation, but inorganic phosphate stimulated Atrazine biodegradation. A subsequent field-scale study consisting of nine (0.75 m3) treatment plots was designed to test four treatment protocols in triplicate. Control plots contained moistened soil; biostimulation plots received 300 p.p.m. phosphate; bioaugmentation plots received 0.5% (w/w) killed, recombinant E. coli cells encapsulating AtzA; and combination plots received phosphate plus the enzyme-containing cells. After 8 weeks, Atrazine levels declined 52% in plots containing killed recombinant E. coli cells, and 77% in combination plots. In contrast, Atrazine levels in control and biostimulation plots did not decline significantly. These data indicate that genetically engineered bacteria overexpressing catabolic genes significantly increased degradation in this soil heavily contaminated with Atrazine.

  • isolation and characterization of a pseudomonas sp that mineralizes the s triazine herbicide Atrazine
    Applied and Environmental Microbiology, 1995
    Co-Authors: Raphi T Mandelbaum, Deborah L Allan, Lawrence P Wackett
    Abstract:

    A bacterium that was capable of metabolizing Atrazine at very high concentrations (>1,000 ppm) was isolated from a herbicide spill site. The organism was differentiated by observing clearing zones on indicator agar plates containing 1,000 ppm Atrazine. Detailed taxonomic studies identified the organism as a Pseudomonas sp., designated ADP, that was dissimilar to currently known species. Pseudomonas sp. strain ADP metabolized Atrazine as its sole nitrogen source. Nongrowing suspended cells also metabolized Atrazine rapidly; for example, 9 x 10(sup9) cells per ml degraded 100 ppm of Atrazine in 90 min. Atrazine was metabolized to hydroxyAtrazine, polar metabolites, and carbon dioxide. When uniformly ring-labeled [(sup14)C]Atrazine was used, 80% of the radioactivity was liberated as (sup14)CO(inf2). These data indicated the triazine ring was completely mineralized. The isolation and characterization of Pseudomonas sp. strain ADP may contribute to efforts on Atrazine bioremediation, particularly in environments containing very high pesticide levels.

  • mineralization of the s triazine ring of Atrazine by stable bacterial mixed cultures
    Applied and Environmental Microbiology, 1993
    Co-Authors: Raphi T Mandelbaum, Lawrence P Wackett, Deborah L Allan
    Abstract:

    Enrichment cultures containing Atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine) at a concentration of 100 ppm (0.46 mM) as a sole nitrogen source were obtained from soils exposed to repeated spills of Atrazine, alachlor, and metolachlor. Bacterial growth occurred concomitantly with formation of metabolites from Atrazine and subsequent biosynthesis of protein. When ring-labeled [14C]Atrazine was used, 80% or more of the s-triazine ring carbon atoms were liberated as 14CO2. HydroxyAtrazine may be an intermediate in the Atrazine mineralization pathway. More than 200 pure cultures isolated from the enrichment cultures failed to utilize Atrazine as a nitrogen source. Mixing pure cultures restored Atrazine-mineralizing activity. Repeated transfer of the mixed cultures led to increased rates of Atrazine metabolism. The rate of Atrazine degradation, even at the elevated concentrations used, far exceeded the rates previously reported in soils, waters, and mixed and pure cultures of bacteria.

Peter Burauel - One of the best experts on this subject based on the ideXlab platform.

  • Transfer of Atrazine Degradation Capability To Mineralize Aged 14C-Labeled Atrazine Residues in Soils
    Journal of Agricultural and Food Chemistry, 2013
    Co-Authors: Nicolai David Jablonowski, Petra Zajkoska, Rosane Martinazzo, Nils Borchard, Jason L. Krutz, Georg Hamacher, Peter Burauel
    Abstract:

    The degradation of environmentally long-term aged (22 years) 14C-labeled Atrazine residues in soil stimulated by inoculation with Atrazine-adapted soil from Belgium, the United States (U.S.), and Brazil at two different moisture regimes (50% WHCmax/slurried conditions) was evaluated. Inoculation of the soil containing the aged 14C-labeled Atrazine residues with 5, 50, and 100% (w/w) Belgian, U.S., or Brazilian Atrazine-adapted soil increased 14C-Atrazine residue mineralization by a factor of 3.1–13.9, depending upon the amount of Atrazine-adapted soil inocula and the moisture conditions. Aged 14C-Atrazine residue mineralization varied between 2 and 8% for Belgian and between 1 and 2% for U.S. and Brazilian soil inoculum at 50% WHCmax but was increased under slurried conditions, accounting for 8–10% (Belgian soil), 2–7% (Brazilian soil), and 3% (American soil). The results show that an increased degradation of long-term aged 14C-labeled Atrazine residues is possible by the transfer of Atrazine-adapted soil...

  • Biochar-mediated [14C]Atrazine mineralization in Atrazine-adapted soils from Belgium and Brazil
    Journal of Agricultural and Food Chemistry, 2013
    Co-Authors: Nicolai David Jablonowski, Petra Zajkoska, Jesús D. Fernández-bayo, Rosane Martinazzo, A. E. Berns, Nils Borchard, Peter Burauel
    Abstract:

    Biochar addition to soil has been reported to reduce the microbial degradation of pesticides due to sorption of the active compound. This study investigated whether the addition of hardwood biochar alters the mineralization of (14)C-labeled Atrazine in two Atrazine-adapted soils from Belgium and Brazil at different moisture regimens. Biochar addition resulted in an equally high or even in a significantly higher Atrazine mineralization compared to the soils without biochar. Statistical analysis revealed that the extent of Atrazine mineralization was more influenced by the specific soil than by the addition of biochar. It was concluded that biochar amendment up to 5% by weight does not negatively affect the mineralization of Atrazine by an Atrazine-adapted soil microflora.

  • Metabolism and Persistence of Atrazine in Several Field Soils with Different Atrazine Application Histories
    Journal of Agricultural and Food Chemistry, 2010
    Co-Authors: Nicolai David Jablonowski, Rosane Martinazzo, Georg Hamacher, Ulrike Langen, Stephan Köppchen, Diana Hofmann, Peter Burauel
    Abstract:

    To assess the potential occurrence of accelerated herbicide degradation in soils, the mineralization and persistence of 14C-labeled and nonlabeled Atrazine was evaluated over 3 months in two soils from Belgium (BS, Atrazine-treated 1973−2008; BC, nontreated) and two soils from Germany (CK, Atrazine-treated 1986−1989; CM, nontreated). Prior to the experiment, accelerated solvent extraction of bulk field soils revealed Atrazine (8.3 and 15.2 μg kg−1) in BS and CK soils and a number of metabolites directly after field sampling, even in BC and CM soils without previous Atrazine treatment, by means of LC-MS/MS analyses. For Atrazine degradation studies, all soils were incubated under different moisture conditions (50% maximum soil water-holding capacity (WHCmax)/slurried conditions). At the end of the incubation, the 14C-Atrazine mineralization was high in BS soil (81 and 83%) and also unexpectedly high in BC soil (40 and 81%), at 50% WHCmax and slurried conditions, respectively. In CK soil, the 14C-Atrazine m...

Tyrone B Hayes - One of the best experts on this subject based on the ideXlab platform.

  • Atrazine induces complete feminization and chemical castration in male african clawed frogs xenopus laevis
    Proceedings of the National Academy of Sciences of the United States of America, 2010
    Co-Authors: Tyrone B Hayes, Vicky Khoury, Anne Narayan, Mariam Nazir, Andrew Park, Travis E Brown, Lillian Adame, Elton Chan, Daniel R Buchholz, Theresa Stueve
    Abstract:

    The herbicide Atrazine is one of the most commonly applied pesticides in the world. As a result, Atrazine is the most commonly detected pesticide contaminant of ground, surface, and drinking water. Atrazine is also a potent endocrine disruptor that is active at low, ecologically relevant concentrations. Previous studies showed that Atrazine adversely affects amphibian larval development. The present study demonstrates the reproductive consequences of Atrazine exposure in adult amphibians. Atrazine-exposed males were both demasculinized (chemically castrated) and completely feminized as adults. Ten percent of the exposed genetic males developed into functional females that copulated with unexposed males and produced viable eggs. Atrazine-exposed males suffered from depressed testosterone, decreased breeding gland size, demasculinized/feminized laryngeal development, suppressed mating behavior, reduced spermatogenesis, and decreased fertility. These data are consistent with effects of Atrazine observed in other vertebrate classes. The present findings exemplify the role that Atrazine and other endocrine-disrupting pesticides likely play in global amphibian declines.

  • Atrazine induced aromatase expression is sf 1 dependent implications for endocrine disruption in wildlife and reproductive cancers in humans
    Environmental Health Perspectives, 2007
    Co-Authors: Toshihiko Yanase, Tyrone B Hayes, Hidetaka Morinaga, Shigeki Gondo, Taijiro Okabe, Masatoshi Nomura, Tomoko Komatsu, Kenichirou Morohashi, Ryoichi Takayanagi, Hajime Nawata
    Abstract:

    BACKGROUND: Atrazine is a potent endocrine disruptor that increases aromatase expression in some human cancer cell lines. The mechanism involves the inhibition of phosphodiesterase and subsequent elevation of cAMP. METHODS: We compared steroidogenic factor 1 (SF-1) expression in Atrazine responsive and non-responsive cell lines and transfected SF-1 into nonresponsive cell lines to assess SF-1's role in Atrazine-induced aromatase. We used a luciferase reporter driven by the SF-1-dependent aromatase promoter (ArPII) to examine activation of this promoter by Atrazine and the related simazine. We mutated the SF-1 binding site to confirm the role of SF-1. We also examined effects of 55 other chemicals. Finally, we examined the ability of Atrazine and simazine to bind to SF-1 and enhance SF-1 binding to ArPII. RESULTS: Atrazine-responsive adrenal carcinoma cells (H295R) expressed 54 times more SF-1 than nonresponsive ovarian granulosa KGN cells. Exogenous SF-1 conveyed Atrazine-responsiveness to otherwise nonresponsive KGN and NIH/3T3 cells. Atrazine induced binding of SF-1 to chromatin and mutation of the SF-1 binding site in ArPII eliminated SF-1 binding and Atrazine-responsiveness in H295R cells. Out of 55 chemicals examined, only Atrazine, simazine, and benzopyrene induced luciferase via ArPII. Atrazine bound directly to SF-1, showing that Atrazine is a ligand for this "orphan" receptor. CONCLUSION: The current findings are consistent with Atrazine's endocrine-disrupting effects in fish, amphibians, and reptiles; the induction of mammary and prostate cancer in laboratory rodents; and correlations between Atrazine and similar reproductive cancers in humans. This study highlights the importance of Atrazine as a risk factor in endocrine disruption in wildlife and reproductive cancers in laboratory rodents and humans.

  • Atrazine induced hermaphroditism at 0 1 ppb in american leopard frogs rana pipiens laboratory and field evidence
    Environmental Health Perspectives, 2002
    Co-Authors: Tyrone B Hayes, Kelly Haston, Mable Tsui, Anhthu Hoang, Cathryn Haeffele, Aaron Vonk
    Abstract:

    Atrazine is the most commonly used herbicide in the United States and probably the world. Atrazine contamination is widespread and can be present in excess of 1.0 ppb even in precipitation and in areas where it is not used. In the current study, we showed that Atrazine exposure (> or = to 0.1 ppb) resulted in retarded gonadal development (gonadal dysgenesis) and testicular oogenesis (hermaphroditism) in leopard frogs (Rana pipiens). Slower developing males even experienced oocyte growth (vitellogenesis). Furthermore, we observed gonadal dysgenesis and hermaphroditism in animals collected from Atrazine-contaminated sites across the United States. These coordinated laboratory and field studies revealed the potential biological impact of Atrazine contamination in the environment. Combined with reported similar effects in Xenopus laevis, the current data raise concern about the effects of Atrazine on amphibians in general and the potential role of Atrazine and other endocrine-disrupting pesticides in amphibian declines.

Guy Soulas - One of the best experts on this subject based on the ideXlab platform.

  • Monitoring of Atrazine treatment on soil bacterial, fungal and Atrazine-degrading communities by quantitative competitive PCR.
    Pest Management Science, 2020
    Co-Authors: Fabrice Martin-laurent, Séverine Piutti, S. Hallet, Isabelle Wagschal, Laurent Philippot, Gérard Catroux, Guy Soulas
    Abstract:

    We report the development of quantitative competitive (QC) PCR assays for quantifying the 16S, 18S ribosomal and atzC genes in nucleic acids directly extracted from soil. QC-PCR assays were standardised, calibrated and evaluated with an experimental study aiming to evaluate the impact of Atrazine application on soil microflora. Comparison of QC-PCR 16S and 18S results with those of soil microbial biomass showed that, following Atrazine application, the microbial biomass was not affected and that the amount of 16S rDNA gene representing ‘bacteria’ increased transitorily, while the amount of 18S rDNA gene representing fungi decreased in soil. In addition, comparison of atzC QC-PCR results with those of Atrazine mineralisation revealed that, in response to Atrazine treatment, the amount of atzC gene increased transitorily in soil pre-treated with Atrazine, suggesting that accelerated Atrazine biodegradation in soil could be due to a transient increase in the size of the Atrazine mineralising community. © 2003 Society of Chemical Industry

  • real time reverse transcription pcr analysis of expression of Atrazine catabolism genes in two bacterial strains isolated from soil
    Journal of Microbiological Methods, 2004
    Co-Authors: Marion Devers, Guy Soulas, Fabrice Martinlaurent
    Abstract:

    Abstract The level of expression of highly conserved, plasmid-borne, and widely dispersed Atrazine catabolic genes ( atz ) was studied by RT-qPCR in two telluric Atrazine-degrading microbes. RT-qPCR assays, based on the use of real-time PCR, were developed in order to quantify atzABCDEF mRNAs in Pseudomonas sp. ADP and atzABC mRNAs in Chelatobacter heintzii . atz gene expression was expressed as mRNA copy number per 10 6 16S rRNA. In Pseudomonas sp. ADP, atz genes were basally expressed. It confirmed Atrazine-degrading kinetics indicating that catabolic activity starts immediately after adding the herbicide. atz gene expression increased transitorily in response to Atrazine treatment. This increase was only observed while low amount of Atrazine remained in the medium. In C. heintzii , only atzA was basally expressed. atzA and atzB expression levels were similarly and significantly increased in response to Atrazine treatment. atzC was not expressed even in the presence of high amounts of Atrazine. This study showed that atz genes are basally expressed and up-regulated in response to Atrazine treatment. atz gene expression patterns are different in Pseudomonas ADP and C. heintzii suggesting that the host may influence the expression of plasmid-borne Atrazine-catabolic potential.

  • isolation and characterisation of new gram negative and gram positive Atrazine degrading bacteria from different french soils
    FEMS Microbiology Ecology, 2001
    Co-Authors: Sandrine Rousseaux, Alain Hartmann, Guy Soulas
    Abstract:

    The capacity of 12 soils to degrade Atrazine was studied in laboratory incubations using radiolabelled Atrazine. Eight soils showed enhanced degradation of this compound. Twenty-five bacterial strains able to degrade Atrazine were isolated by an enrichment method from 10 of these soils. These soils were chosen for their wide range of physico-chemical characteristics. Their history of treatment with Atrazine was also variable. The genetic diversity of Atrazine degraders was determined by amplified ribosomal restriction analysis (ARDRA) of the 16S rDNA gene with three restriction endonucleases. The 25 bacterial strains were grouped into five ARDRA types. By sequencing and aligning the 16S rDNA genes, the isolates were shown to belong to the Gram-negative species Chelatobacter heintzii, Aminobacter aminovorans, Stenotrophomonas maltophilia and to the Gram-positive genus Arthrobacter crystallopoietes. These species were not described previously as being capable of Atrazine degradation. Most Gram-negative bacteria could mineralise 14C ring labelled Atrazine and carried the atzA, atzB, atzC and trzD genes. Gram-positive strains could convert Atrazine to cyanuric acid and carried only the atzB and atzC genes. In this study, we describe the Atrazine degradation capacities and corresponding genes in bacterial species that were not known as Atrazine degraders. We report for the first time the occurrence of the trzD gene in these Atrazine-mineralising bacteria and we demonstrate the potential use of colony hybridisation to isolate bacteria involved in Atrazine degradation.