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Xu J, Li T, Huang WE, Zhou NY. Semi-rational design of nitroarene dioxygenase for catalytic ability toward 2,4-dichloronitrobenzene. Appl Environ Microbiol 2024:e0143623. [PMID: 38709097 DOI: 10.1128/aem.01436-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 04/05/2024] [Indexed: 05/07/2024] Open
Abstract
Rieske non-heme dioxygenase family enzymes play an important role in the aerobic biodegradation of nitroaromatic pollutants, but no active dioxygenases are available in nature for initial reactions in the degradation of many refractory pollutants like 2,4-dichloronitrobenzene (24DCNB). Here, we report the engineering of hotspots in 2,3-dichloronitrobenzene dioxygenase from Diaphorobacter sp. strain JS3051, achieved through molecular dynamic simulation analysis and site-directed mutagenesis, with the aim of enhancing its catalytic activity toward 24DCNB. The computationally predicted activity scores were largely consistent with the detected activities in wet experiments. Among them, the two most beneficial mutations (E204M and M248I) were obtained, and the combined mutant reached up to a 62-fold increase in activity toward 24DCNB, generating a single product, 3,5-dichlorocatechol, which is a naturally occurring compound. In silico analysis confirmed that residue 204 affected the substrate preference for meta-substituted nitroarenes, while residue 248 may influence substrate preference by interaction with residue 295. Overall, this study provides a framework for manipulating nitroarene dioxygenases using computational methods to address various nitroarene contamination problems.IMPORTANCEAs a result of human activities, various nitroaromatic pollutants continue to enter the biosphere with poor degradability, and dioxygenation is an important kickoff step to remove toxic nitro-groups and convert them into degradable products. The biodegradation of many nitroarenes has been reported over the decades; however, many others still lack corresponding enzymes to initiate their degradation. Although rieske non-heme dioxygenase family enzymes play extraordinarily important roles in the aerobic biodegradation of various nitroaromatic pollutants, prediction of their substrate specificity is difficult. This work greatly improved the catalytic activity of dioxygenase against 2,4-dichloronitrobenzene by computer-aided semi-rational design, paving a new way for the evolution strategy of nitroarene dioxygenase. This study highlights the potential for using enzyme structure-function information with computational pre-screening methods to rapidly tailor the catalytic functions of enzymes toward poorly biodegradable contaminants.
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Affiliation(s)
- Jia Xu
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Tao Li
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Wei E Huang
- Department of Engineering Science, University of Oxford, Oxford, United Kingdom
| | - Ning-Yi Zhou
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
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Godínez-Pérez CM, Loza A, Hurtado JM, Gutiérrez-Ríos RM. The benzoyl-CoA pathway serves as a genomic marker to identify the oxygen requirements in the degradation of aromatic hydrocarbons. Front Microbiol 2024; 14:1308626. [PMID: 38264488 PMCID: PMC10803450 DOI: 10.3389/fmicb.2023.1308626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 12/22/2023] [Indexed: 01/25/2024] Open
Abstract
The first step of anaerobic benzoate degradation is the formation of benzoyl-coenzyme A by benzoate-coenzyme A ligase (BCL). The anaerobic route is steered by benzoyl-CoA reductase, which promotes benzoyl-CoA breakdown, which is subsequently oxidized. In certain bacteria at low oxygen conditions, the aerobic metabolism of monoaromatic hydrocarbons occurs through the degradation Box pathway. These pathways have undergone experimental scrutiny in Alphaproteobacteria and Betaproteobacteria and have also been explored bioinformatically in representative Betaproteobacteria. However, there is a gap in our knowledge regarding the distribution of the benzoyl-CoA pathway and the evolutionary forces propelling its adaptation beyond that of representative bacteria. To address these questions, we used bioinformatic procedures to identify the BCLs and the lower pathways that transform benzoyl-CoA. These procedures included the identification of conserved motifs. As a result, we identified two motifs exclusive to BCLs, describing some of the catalytic properties of this enzyme. These motifs helped to discern BCLs from other aryl-CoA ligases effectively. The predicted BCLs and the enzymes of lower pathways were used as genomic markers for identifying aerobic, anaerobic, or hybrid catabolism, which we found widely distributed in Betaproteobacteria. Despite these enhancements, our approach failed to distinguish orthologs from a small cluster of paralogs exhibiting all the specified features to predict an ortholog. Nonetheless, the conducted phylogenetic analysis and the properties identified in the genomic context aided in formulating hypotheses about how this redundancy contributes to refining the catabolic strategy employed by these bacteria to degrade the substrates.
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Affiliation(s)
| | | | | | - Rosa-María Gutiérrez-Ríos
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
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Alviz-Gazitua P, Durán RE, Millacura FA, Cárdenas F, Rojas LA, Seeger M. Cupriavidus metallidurans CH34 Possesses Aromatic Catabolic Versatility and Degrades Benzene in the Presence of Mercury and Cadmium. Microorganisms 2022; 10:microorganisms10020484. [PMID: 35208938 PMCID: PMC8879955 DOI: 10.3390/microorganisms10020484] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Revised: 02/17/2022] [Accepted: 02/17/2022] [Indexed: 11/16/2022] Open
Abstract
Heavy metal co-contamination in crude oil-polluted environments may inhibit microbial bioremediation of hydrocarbons. The model heavy metal-resistant bacterium Cupriavidus metallidurans CH34 possesses cadmium and mercury resistance, as well as genes related to the catabolism of hazardous BTEX aromatic hydrocarbons. The aims of this study were to analyze the aromatic catabolic potential of C. metallidurans CH34 and to determine the functionality of the predicted benzene catabolic pathway and the influence of cadmium and mercury on benzene degradation. Three chromosome-encoded bacterial multicomponent monooxygenases (BMMs) are involved in benzene catabolic pathways. Growth assessment, intermediates identification, and gene expression analysis indicate the functionality of the benzene catabolic pathway. Strain CH34 degraded benzene via phenol and 2-hydroxymuconic semialdehyde. Transcriptional analyses revealed a transition from the expression of catechol 2,3-dioxygenase (tomB) in the early exponential phase to catechol 1,2-dioxygenase (catA1 and catA2) in the late exponential phase. The minimum inhibitory concentration to Hg (II) and Cd (II) was significantly lower in the presence of benzene, demonstrating the effect of co-contamination on bacterial growth. Notably, this study showed that C. metallidurans CH34 degraded benzene in the presence of Hg (II) or Cd (II).
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Affiliation(s)
- Pablo Alviz-Gazitua
- Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química & Centro de Biotecnología, Universidad Técnica Federico Santa María, Avenida España 1680, Valparaíso 2390123, Chile; (P.A.-G.); (R.E.D.); (F.A.M.); (F.C.)
- Departamento de Ciencias Biológicas y Biodiversidad, Universidad de los Lagos, Osorno 5311890, Chile
| | - Roberto E. Durán
- Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química & Centro de Biotecnología, Universidad Técnica Federico Santa María, Avenida España 1680, Valparaíso 2390123, Chile; (P.A.-G.); (R.E.D.); (F.A.M.); (F.C.)
| | - Felipe A. Millacura
- Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química & Centro de Biotecnología, Universidad Técnica Federico Santa María, Avenida España 1680, Valparaíso 2390123, Chile; (P.A.-G.); (R.E.D.); (F.A.M.); (F.C.)
- School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JQ, UK
| | - Franco Cárdenas
- Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química & Centro de Biotecnología, Universidad Técnica Federico Santa María, Avenida España 1680, Valparaíso 2390123, Chile; (P.A.-G.); (R.E.D.); (F.A.M.); (F.C.)
- Centro Regional de Estudios en Alimentos Saludables (CREAS), Avenida Universidad 330, Curauma, Valparaíso 2373223, Chile
| | - Luis A. Rojas
- Departamento de Química, Facultad de Ciencias, Universidad Católica del Norte, Avenida Angamos 610, Antofagasta 1270709, Chile;
| | - Michael Seeger
- Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química & Centro de Biotecnología, Universidad Técnica Federico Santa María, Avenida España 1680, Valparaíso 2390123, Chile; (P.A.-G.); (R.E.D.); (F.A.M.); (F.C.)
- Correspondence: or
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4
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Wang B, Gao J, Xu J, Fu X, Han H, Li Z, Wang L, Zhang F, Tian Y, Peng R, Yao Q. Optimization and reconstruction of two new complete degradation pathways for 3-chlorocatechol and 4-chlorocatechol in Escherichia coli. JOURNAL OF HAZARDOUS MATERIALS 2021; 419:126428. [PMID: 34171665 DOI: 10.1016/j.jhazmat.2021.126428] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 05/11/2021] [Accepted: 06/16/2021] [Indexed: 06/13/2023]
Abstract
Chlorinated aromatic compounds are a serious environmental concern because of their widespread occurrence throughout the environment. Although several microorganisms have evolved to gain the ability to degrade chlorinated aromatic compounds and use them as carbon sources, they still cannot meet the diverse needs of pollution remediation. In this study, the degradation pathways for 3-chlorocatechol (3CC) and 4-chlorocatechol (4CC) were successfully reconstructed by the optimization, synthesis, and assembly of functional genes from different strains. The addition of a 13C-labeled substrate and functional analysis of different metabolic modules confirmed that the genetically engineered strains can metabolize chlorocatechol similar to naturally degrading strains. The strain containing either of these artificial pathways can degrade catechol, 3CC, and 4CC completely, although differences in the degradation efficiency may be noted. Proteomic analysis and scanning electron microscopy observation showed that 3CC and 4CC have toxic effects on Escherichia coli, but the engineered bacteria can significantly eliminate these inhibitory effects. As core metabolic pathways for the degradation of chloroaromatics, the two chlorocatechol degradation pathways constructed in this study can be used to construct pollution remediation-engineered bacteria, and the related technologies may be applied to construct complete degradation pathways for complex organic hazardous materials.
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Affiliation(s)
- Bo Wang
- Shanghai Key laboratory of Agricultural Genetics and Breeding, Agro-Biotechnology Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, PR China
| | - Jianjie Gao
- Shanghai Key laboratory of Agricultural Genetics and Breeding, Agro-Biotechnology Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, PR China
| | - Jing Xu
- Shanghai Key laboratory of Agricultural Genetics and Breeding, Agro-Biotechnology Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, PR China
| | - Xiaoyan Fu
- Shanghai Key laboratory of Agricultural Genetics and Breeding, Agro-Biotechnology Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, PR China
| | - Hongjuan Han
- Shanghai Key laboratory of Agricultural Genetics and Breeding, Agro-Biotechnology Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, PR China
| | - Zhenjun Li
- Shanghai Key laboratory of Agricultural Genetics and Breeding, Agro-Biotechnology Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, PR China
| | - Lijuan Wang
- Shanghai Key laboratory of Agricultural Genetics and Breeding, Agro-Biotechnology Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, PR China
| | - Fujian Zhang
- Shanghai Key laboratory of Agricultural Genetics and Breeding, Agro-Biotechnology Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, PR China
| | - Yongsheng Tian
- Shanghai Key laboratory of Agricultural Genetics and Breeding, Agro-Biotechnology Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, PR China.
| | - Rihe Peng
- Shanghai Key laboratory of Agricultural Genetics and Breeding, Agro-Biotechnology Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, PR China.
| | - Quanhong Yao
- Shanghai Key laboratory of Agricultural Genetics and Breeding, Agro-Biotechnology Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, PR China.
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Jõesaar M, Viggor S, Heinaru E, Naanuri E, Mehike M, Leito I, Heinaru A. Strategy of Pseudomonas pseudoalcaligenes C70 for effective degradation of phenol and salicylate. PLoS One 2017; 12:e0173180. [PMID: 28257519 PMCID: PMC5336314 DOI: 10.1371/journal.pone.0173180] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 02/16/2017] [Indexed: 01/08/2023] Open
Abstract
Phenol- and naphthalene-degrading indigenous Pseudomonas pseudoalcaligenes strain C70 has great potential for the bioremediation of polluted areas. It harbours two chromosomally located catechol meta pathways, one of which is structurally and phylogenetically very similar to the Pseudomonas sp. CF600 dmp operon and the other to the P. stutzeri AN10 nah lower operon. The key enzymes of the catechol meta pathway, catechol 2,3-dioxygenase (C23O) from strain C70, PheB and NahH, have an amino acid identity of 85%. The metabolic and regulatory phenotypes of the wild-type and the mutant strain C70ΔpheB lacking pheB were evaluated. qRT-PCR data showed that in C70, the expression of pheB- and nahH-encoded C23O was induced by phenol and salicylate, respectively. We demonstrate that strain C70 is more effective in the degradation of phenol and salicylate, especially at higher substrate concentrations, when these compounds are present as a mixture; i.e., when both pathways are expressed. Moreover, NahH is able to substitute for the deleted PheB in phenol degradation when salicylate is also present in the growth medium. The appearance of a yellow intermediate 2-hydroxymuconic semialdehyde was followed by the accumulation of catechol in salicylate-containing growth medium, and lower expression levels and specific activities of the C23O of the sal operon were detected. However, the excretion of the toxic intermediate catechol to the growth medium was avoided when the growth medium was supplemented with phenol, seemingly due to the contribution of the second meta pathway encoded by the phe genes.
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Affiliation(s)
- Merike Jõesaar
- Institute of Molecular and Cell Biology, Faculty of Science and Technology, University of Tartu, Tartu, Estonia
| | - Signe Viggor
- Institute of Molecular and Cell Biology, Faculty of Science and Technology, University of Tartu, Tartu, Estonia
| | - Eeva Heinaru
- Institute of Molecular and Cell Biology, Faculty of Science and Technology, University of Tartu, Tartu, Estonia
| | - Eve Naanuri
- Institute of Molecular and Cell Biology, Faculty of Science and Technology, University of Tartu, Tartu, Estonia
| | - Maris Mehike
- Institute of Molecular and Cell Biology, Faculty of Science and Technology, University of Tartu, Tartu, Estonia
| | - Ivo Leito
- Institute of Chemistry, Faculty of Science and Technology, University of Tartu, Tartu, Estonia
| | - Ain Heinaru
- Institute of Molecular and Cell Biology, Faculty of Science and Technology, University of Tartu, Tartu, Estonia
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6
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Biochemical and Genetic Bases of Indole-3-Acetic Acid (Auxin Phytohormone) Degradation by the Plant-Growth-Promoting Rhizobacterium Paraburkholderia phytofirmans PsJN. Appl Environ Microbiol 2016; 83:AEM.01991-16. [PMID: 27795307 DOI: 10.1128/aem.01991-16] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 10/14/2016] [Indexed: 12/16/2022] Open
Abstract
Several bacteria use the plant hormone indole-3-acetic acid (IAA) as a sole carbon and energy source. A cluster of genes (named iac) encoding IAA degradation has been reported in Pseudomonas putida 1290, but the functions of these genes are not completely understood. The plant-growth-promoting rhizobacterium Paraburkholderia phytofirmans PsJN harbors iac gene homologues in its genome, but with a different gene organization and context than those of P. putida 1290. The iac gene functions enable P. phytofirmans to use IAA as a sole carbon and energy source. Employing a heterologous expression system approach, P. phytofirmans iac genes with previously undescribed functions were associated with specific biochemical steps. In addition, two uncharacterized genes, previously unreported in P. putida and found to be related to major facilitator and tautomerase superfamilies, are involved in removal of an IAA metabolite called dioxindole-3-acetate. Similar to the case in strain 1290, IAA degradation proceeds through catechol as intermediate, which is subsequently degraded by ortho-ring cleavage. A putative two-component regulatory system and a LysR-type regulator, which apparently respond to IAA and dioxindole-3-acetate, respectively, are involved in iac gene regulation in P. phytofirmans These results provide new insights about unknown gene functions and complex regulatory mechanisms in IAA bacterial catabolism. IMPORTANCE This study describes indole-3-acetic acid (auxin phytohormone) degradation in the well-known betaproteobacterium P. phytofirmans PsJN and comprises a complete description of genes, some of them with previously unreported functions, and the general basis of their gene regulation. This work contributes to the understanding of how beneficial bacteria interact with plants, helping them to grow and/or to resist environmental stresses, through a complex set of molecular signals, in this case through degradation of a highly relevant plant hormone.
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7
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George KW, Hay AG. Bacterial strategies for growth on aromatic compounds. ADVANCES IN APPLIED MICROBIOLOGY 2016; 74:1-33. [PMID: 21459192 DOI: 10.1016/b978-0-12-387022-3.00005-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Although the biodegradation of aromatic compounds has been studied for over 40 years, there is still much to learn about the strategies bacteria employ for growth on novel substrates. Elucidation of these strategies is crucial for predicting the environmental fate of aromatic pollutants and will provide a framework for the development of engineered bacteria and degradation pathways. In this chapter, we provide an overview of studies that have advanced our knowledge of bacterial adaptation to aromatic compounds. We have divided these strategies into three broad categories: (1) recruitment of catabolic genes, (2) expression of "repair" or detoxification proteins, and (3) direct alteration of enzymatic properties. Specific examples from the literature are discussed, with an eye toward the molecular mechanisms that underlie each strategy.
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Affiliation(s)
- Kevin W George
- Field of Environmental Toxicology, Cornell University Ithaca, New York, USA; Department of Microbiology, Wing Hall, Cornell University Ithaca, New York, USA
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8
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Ricker N, Shen SY, Goordial J, Jin S, Fulthorpe RR. PacBio SMRT assembly of a complex multi-replicon genome reveals chlorocatechol degradative operon in a region of genome plasticity. Gene 2016; 586:239-47. [PMID: 27063562 DOI: 10.1016/j.gene.2016.04.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 03/14/2016] [Accepted: 04/05/2016] [Indexed: 01/03/2023]
Abstract
We have sequenced a Burkholderia genome that contains multiple replicons and large repetitive elements that would make it inherently difficult to assemble by short read sequencing technologies. We illustrate how the integrated long read correction algorithms implemented through the PacBio Single Molecule Real-Time (SMRT) sequencing technology successfully provided a de novo assembly that is a reasonable estimate of both the gene content and genome organization without making any further modifications. This assembly is comparable to related organisms assembled by more labour intensive methods. Our assembled genome revealed regions of genome plasticity for further investigation, one of which harbours a chlorocatechol degradative operon highly homologous to those previously identified on globally ubiquitous plasmids. In an ideal world, this assembly would still require experimental validation to confirm gene order and copy number of repeated elements. However, we submit that particularly in instances where a polished genome is not the primary goal of the sequencing project, PacBio SMRT sequencing provides a financially viable option for generating a biologically relevant genome estimate that can be utilized by other researchers for comparative studies.
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Affiliation(s)
- N Ricker
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1095 Military Trail, Scarborough, Ontario M1C 1A4, Canada
| | - S Y Shen
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1095 Military Trail, Scarborough, Ontario M1C 1A4, Canada
| | - J Goordial
- Department of Natural Resource Sciences, McGill University, Macdonald Campus, 21111 Lakeshore Rd., Sainte Anne de Bellevue, Quebec H9X 3V9, Canada
| | - S Jin
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1095 Military Trail, Scarborough, Ontario M1C 1A4, Canada
| | - R R Fulthorpe
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1095 Military Trail, Scarborough, Ontario M1C 1A4, Canada.
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9
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Hierarchy of Carbon Source Utilization in Soil Bacteria: Hegemonic Preference for Benzoate in Complex Aromatic Compound Mixtures Degraded by Cupriavidus pinatubonensis Strain JMP134. Appl Environ Microbiol 2015; 81:3914-24. [PMID: 25795675 DOI: 10.1128/aem.04207-14] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Accepted: 03/17/2015] [Indexed: 12/23/2022] Open
Abstract
Cupriavidus pinatubonensis JMP134, like many other environmental bacteria, uses a range of aromatic compounds as carbon sources. Previous reports have shown a preference for benzoate when this bacterium grows on binary mixtures composed of this aromatic compound and 4-hydroxybenzoate or phenol. However, this observation has not been extended to other aromatic mixtures resembling a more archetypal context. We carried out a systematic study on the substrate preference of C. pinatubonensis JMP134 growing on representative aromatic compounds channeled through different catabolic pathways described in aerobic bacteria. Growth tests of nearly the entire set of binary combinations and in mixtures composed of 5 or 6 aromatic components showed that benzoate and phenol were always the preferred and deferred growth substrates, respectively. This pattern was supported by kinetic analyses that showed shorter times to initiate consumption of benzoate in aromatic compound mixtures. Gene expression analysis by real-time reverse transcription-PCR (RT-PCR) showed that, in all mixtures, the repression by benzoate over other catabolic pathways was exerted mainly at the transcriptional level. Additionally, inhibition of benzoate catabolism suggests that its multiple repressive actions are not mediated by a sole mechanism, as suggested by dissimilar requirements of benzoate degradation for effective repression in different aromatic compound mixtures. The hegemonic preference for benzoate over multiple aromatic carbon sources is not explained on the basis of growth rate and/or biomass yield on each single substrate or by obvious chemical or metabolic properties of these aromatic compounds.
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Dobslaw D, Engesser KH. Degradation of toluene by ortho cleavage enzymes in Burkholderia fungorum FLU100. Microb Biotechnol 2014; 8:143-54. [PMID: 25130674 PMCID: PMC4321380 DOI: 10.1111/1751-7915.12147] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 06/28/2014] [Indexed: 11/28/2022] Open
Abstract
Burkholderia fungorum FLU100 simultaneously oxidized any mixture of toluene, benzene and mono-halogen benzenes to (3-substituted) catechols with a selectivity of nearly 100%. Further metabolism occurred via enzymes of ortho cleavage pathways with complete mineralization. During the transformation of 3-methylcatechol, 4-carboxymethyl-2-methylbut-2-en-4-olide (2-methyl-2-enelactone, 2-ML) accumulated transiently, being further mineralized only after a lag phase of 2 h in case of cells pre-grown on benzene or mono-halogen benzenes. No lag phase, however, occurred after growth on toluene. Cultures inhibited by chloramphenicol after growth on benzene or mono-halogen benzenes were unable to metabolize 2-ML supplied externally, even after prolonged incubation. A control culture grown with toluene did not show any lag phase and used 2-ML as a substrate. This means that 2-ML is an intermediate of toluene degradation and converted by specific enzymes. The conversion of 4-methylcatechol as a very minor by-product of toluene degradation in strain FLU100 resulted in the accumulation of 4-carboxymethyl-4-methylbut-2-en-4-olide (4-methyl-2-enelactone, 4-ML) as a dead-end product, excluding its nature as a possible intermediate. Thus, 3-methylcyclohexa-3,5-diene-1,2-diol, 3-methylcatechol, 2-methyl muconate and 2-ML were identified as central intermediates of productive ortho cleavage pathways for toluene metabolism in B. fungorum FLU100.
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Affiliation(s)
- Daniel Dobslaw
- Department of Biological Waste Air Purification, Institute of Sanitary Engineering, Water Quality and Solid Waste Management, University of Stuttgart, Bandtäle 2, Stuttgart, D-70569, Germany
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11
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Kumar A, Trefault N, Olaniran AO. Microbial degradation of 2,4-dichlorophenoxyacetic acid: Insight into the enzymes and catabolic genes involved, their regulation and biotechnological implications. Crit Rev Microbiol 2014; 42:194-208. [DOI: 10.3109/1040841x.2014.917068] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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12
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Endo R, Ohtsubo Y, Tsuda M, Nagata Y. Growth Inhibition by Metabolites of γ-Hexachlorocyclohexane inSphingobium japonicumUT26. Biosci Biotechnol Biochem 2014; 70:1029-32. [PMID: 16636477 DOI: 10.1271/bbb.70.1029] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The growth of a gamma-hexachlorocyclohexane (gamma-HCH)-degrading bacterium Sphingobium japonicum (formerly Sphingomonas paucimobilis) UT26 in rich medium was inhibited by gamma-HCH. This growth inhibition was not observed in a mutant that lacked the initial or second step enzymatic activity for gamma-HCH degradation, suggesting that metabolites of gamma-HCH are toxic to UT26. Two metabolites of gamma-HCH, 2,5-dichlorophenol (2,5-DCP) and 2,5-dichlorohydroquinone (2,5-DCHQ), showed a direct toxic effect on UT26 and other sphingomonad strains. Because only 2,5-DCP accumulated during gamma-HCH degradation, 2,5-DCP is thought to be a main compound for growth inhibition.
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Affiliation(s)
- Ryo Endo
- Department of Environmental Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Japan
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13
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Arora PK, Srivastava A, Singh VP. Novel degradation pathway of 4-chloro-2-aminophenol via 4-chlorocatechol in Burkholderia sp. RKJ 800. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2014; 21:2298-2304. [PMID: 24057966 DOI: 10.1007/s11356-013-2167-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Accepted: 09/12/2013] [Indexed: 06/02/2023]
Abstract
Burkholderia sp. RKJ 800 utilized 4-chloro-2-aminophenol (4C2AP) as the sole carbon and energy source and degraded it with release of chloride and ammonium ions. The metabolic pathway of degradation of 4C2AP was studied and a novel intermediate, 4-chlorocatechol was identified as a major degradation product of 4C2AP using high-performance liquid chromatography and gas chromatography-mass spectrometry. Enzyme activities for 4C2AP-deaminase and 4-chlorocatechol-1,2-dioxygenase were detected in the crude extracts of the 4C2AP-induced cells of strain RKJ 800. The activity of the 4C2AP-deaminase confirmed the formation of 4-chlorocatechol from 4C2AP and the 4-chlorocatechol-1,2-dioxygenase activity suggested the cleavage of 4-chlorocatechol into 3-chloro-cis,cis-muconate. On the basis of the identified metabolites, we have proposed a novel degradation pathway of 4C2AP for Burkholderia sp. RKJ 800. Furthermore, the potential of Burkholderia sp. RKJ 800 to degrade 4C2AP in soil was also investigated using microcosm studies under laboratory conditions. The results of microcosm studies conclude that Burkholderia sp. RKJ 800 was able to degrade 4C2AP in soil and may be used to remediate 4C2AP-contaminated site. This is the first report of (1) the formation of 4-chlorocatechol and 3-chloro-cis,cis-muconate in the degradation pathway of 4C2AP and (2) bioremediation of 4C2AP by any bacterium.
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Affiliation(s)
- Pankaj Kumar Arora
- Department of Plant Science, Faculty of Applied Sciences, MJP Rohilkhand University, Bareilly, 243006, India.
| | - Alok Srivastava
- Department of Plant Science, Faculty of Applied Sciences, MJP Rohilkhand University, Bareilly, 243006, India
| | - Vijay Pal Singh
- Department of Plant Science, Faculty of Applied Sciences, MJP Rohilkhand University, Bareilly, 243006, India
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Jiménez JI, Pérez-Pantoja D, Chavarría M, Díaz E, de Lorenzo V. A second chromosomal copy of thecatAgene endowsPseudomonas putida mt-2 with an enzymatic safety valve for excess of catechol. Environ Microbiol 2014; 16:1767-78. [DOI: 10.1111/1462-2920.12361] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2013] [Accepted: 12/10/2013] [Indexed: 11/30/2022]
Affiliation(s)
- Jose I. Jiménez
- Centro de Investigaciones Biológicas; Consejo Superior de Investigaciones Científicas; 28049 Madrid Spain
- Centro Nacional de Biotecnología; Consejo Superior de Investigaciones Científicas; 28049 Madrid Spain
| | - Danilo Pérez-Pantoja
- Centro Nacional de Biotecnología; Consejo Superior de Investigaciones Científicas; 28049 Madrid Spain
| | - Max Chavarría
- Centro Nacional de Biotecnología; Consejo Superior de Investigaciones Científicas; 28049 Madrid Spain
| | - Eduardo Díaz
- Centro de Investigaciones Biológicas; Consejo Superior de Investigaciones Científicas; 28049 Madrid Spain
| | - Víctor de Lorenzo
- Centro Nacional de Biotecnología; Consejo Superior de Investigaciones Científicas; 28049 Madrid Spain
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15
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George KW, Hay A. Less is more: reduced catechol production permits Pseudomonas putida F1 to grow on styrene. Microbiology (Reading) 2012; 158:2781-2788. [DOI: 10.1099/mic.0.058230-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Kevin W. George
- Field of Environmental Toxicology, Cornell University, Ithaca, NY 14850, USA
| | - Anthony Hay
- Department of Microbiology, Cornell University, Ithaca, NY 14850, USA
- Field of Environmental Toxicology, Cornell University, Ithaca, NY 14850, USA
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16
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Gallego A, Gemini VL, Rossen AA, Rossi SL, Trípodi V, Corach D, Planes E, Korol SE. Aerobic degradation of 3-chlorobenzoic acid by an indigenous strain isolated from a polluted river. World J Microbiol Biotechnol 2012; 28:1245-52. [PMID: 22805844 DOI: 10.1007/s11274-011-0928-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2010] [Accepted: 10/18/2011] [Indexed: 11/26/2022]
Abstract
An indigenous strain of Pseudomonas putida capable of degrading 3-chlorobenzoic acid as the sole carbon source was isolated from the Riachuelo, a polluted river in Buenos Aires. Aerobic biodegradation assays were performed using a 2-l microfermentor. Biodegradation was evaluated by spectrophotometry, chloride release, gas chromatography and microbial growth. Detoxification was evaluated by using Vibrio fischeri, Pseudokirchneriella subcapitata and Lactuca sativa as test organisms. The indigenous bacterial strain degrades 100 mg l(-1) 3-chlorobenzoic acid in 14 h with a removal efficiency of 92.0 and 86.1% expressed as compound and chemical oxygen demand removal, respectively. The strain was capable of degrading up to 1,000 mg of the compound l(-1). Toxicity was not detected at the end of the biodegradation process. Besides initial concentration, the effect of different factors, such as initial pH, initial inoculum, adaptation to the compound and presence of other substrates and toxic related compounds, was studied.
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Affiliation(s)
- Alfredo Gallego
- Faculty of Pharmacy and Biochemistry, University of Buenos Aires, Junín 956, 1113 Buenos Aires, Argentina.
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Méndez V, Agulló L, González M, Seeger M. The homogentisate and homoprotocatechuate central pathways are involved in 3- and 4-hydroxyphenylacetate degradation by Burkholderia xenovorans LB400. PLoS One 2011; 6:e17583. [PMID: 21423751 PMCID: PMC3053370 DOI: 10.1371/journal.pone.0017583] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Accepted: 02/05/2011] [Indexed: 11/24/2022] Open
Abstract
Background Genome characterization of the model PCB-degrading bacterium Burkholderia xenovorans LB400 revealed the presence of eleven central pathways for aromatic compounds degradation, among them, the homogentisate and the homoprotocatechuate pathways. However, the functionality of these central pathways in strain LB400 has not been assessed and related peripheral pathways has not been described. Methodology/Principal Findings The aims of this study were to determine the functionality of the homogentisate and homoprotocatechuate central pathways in B. xenovorans LB400 and to establish their role in 3-hydroxyphenylacetate (3-HPA) and 4-hydroxyphenylacetate (4-HPA) catabolism. Strain LB400 was able to grow using 3-HPA and 4-HPA as sole carbon source. A genomic search in LB400 suggested the presence of mhaAB and hpaBC genes clusters encoding proteins of the 3-hydroxyphenylacetate and 4-hydroxyphenylacetate peripheral pathways. LB400 cells grown with 3-HPA and 4-HPA degraded homogentisate and homoprotocatechuate and showed homogentisate 1,2-dioxygenase and homoprotocatechuate 2,3-dioxygenase activities. Transcriptional analyses by RT-PCR showed the expression of two chromosomally-encoded homogentisate dioxygenases (BxeA2725 and BxeA3900) and the hpaD gene encoding the homoprotocatechuate 2,3-dioxygenase during 3-HPA and 4-HPA degradation. The proteome analyses by two-dimensional polyacrilamide gel electrophoresis of B. xenovorans LB400 grown in 3-HPA and 4-HPA showed the induction of fumarylacetoacetate hydrolase HmgB (BxeA3899). Conclusions/Significance This study revealed that strain LB400 used both homogentisate and homoprotocatechuate ring-cleavage pathways for 3- hydroxyphenylacetate and 4-hydroxyphenylacetate catabolism and that these four catabolic routes are functional, confirming the metabolic versatility of B. xenovorans LB400.
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Affiliation(s)
- Valentina Méndez
- Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química and Center for Nanotechnology and Systems Biology, Universidad Técnica Federico Santa María, Valparaíso, Chile
| | - Loreine Agulló
- Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química and Center for Nanotechnology and Systems Biology, Universidad Técnica Federico Santa María, Valparaíso, Chile
| | - Myriam González
- Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química and Center for Nanotechnology and Systems Biology, Universidad Técnica Federico Santa María, Valparaíso, Chile
| | - Michael Seeger
- Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química and Center for Nanotechnology and Systems Biology, Universidad Técnica Federico Santa María, Valparaíso, Chile
- * E-mail:
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George KW, Kagle J, Junker L, Risen A, Hay AG. Growth of Pseudomonas putida F1 on styrene requires increased catechol-2,3-dioxygenase activity, not a new hydrolase. Microbiology (Reading) 2011; 157:89-98. [DOI: 10.1099/mic.0.042531-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Pseudomonas putida F1 cannot grow on styrene despite being able to degrade it through the toluene degradation (tod) pathway. Previous work had suggested that this was because TodF, the meta-fission product (MFP) hydrolase, was unable to metabolize the styrene MFP 2-hydroxy-6-vinylhexa-2,4-dienoate. Here we demonstrate via kinetic and growth analyses that the substrate specificity of TodF is not the limiting factor preventing F1 from growing on styrene. Rather, we found that the metabolite 3-vinylcatechol accumulated during styrene metabolism and that micromolar concentrations of this intermediate inactivated TodE, the catechol-2,3-dioxygenase (C23O) responsible for its cleavage. Analysis of cells growing on styrene suggested that inactivation of TodE and the subsequent accumulation of 3-vinylcatechol resulted in toxicity and cell death. We found that simply overexpressing TodE on a plasmid (pTodE) was all that was necessary to allow F1 to grow on styrene. Similar results were also obtained by expressing a related C23O, DmpB from Pseudomonas sp. CF600, in tandem with its plant-like ferredoxin, DmpQ (pDmpQB). Further analysis revealed that the ability of F1 (pDmpQB) and F1 (pTodE) to grow on styrene correlated with increased C23O activity as well as resistance of the enzyme to 3-vinylcatechol-mediated inactivation. Although TodE inactivation by 3-halocatechols has been studied before, to our knowledge, this is the first published report demonstrating inactivation by a 3-vinylcatechol. Given the ubiquity of catechol intermediates in aromatic hydrocarbon metabolism, our results further demonstrate the importance of C23O inactivation as a determinant of growth substrate specificity.
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Affiliation(s)
- Kevin W. George
- Department of Microbiology, Cornell University Ithaca, NY 14850, USA
- Field of Environmental Toxicology, Cornell University Ithaca, NY 14850, USA
| | - Jeanne Kagle
- Department of Microbiology, Cornell University Ithaca, NY 14850, USA
| | - Lauren Junker
- Department of Microbiology, Cornell University Ithaca, NY 14850, USA
| | - Amy Risen
- Department of Microbiology, Cornell University Ithaca, NY 14850, USA
- Field of Environmental Toxicology, Cornell University Ithaca, NY 14850, USA
| | - Anthony G. Hay
- Department of Microbiology, Cornell University Ithaca, NY 14850, USA
- Field of Environmental Toxicology, Cornell University Ithaca, NY 14850, USA
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Saavedra JM, Acevedo F, González M, Seeger M. Mineralization of PCBs by the genetically modified strain Cupriavidus necator JMS34 and its application for bioremediation of PCBs in soil. Appl Microbiol Biotechnol 2010; 87:1543-54. [DOI: 10.1007/s00253-010-2575-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2010] [Revised: 03/18/2010] [Accepted: 03/18/2010] [Indexed: 11/29/2022]
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20
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Bobadilla Fazzini RA, Preto MJ, Quintas ACP, Bielecka A, Dos Santos VAPM. Consortia modulation of the stress response: proteomic analysis of single strain versus mixed culture. Environ Microbiol 2010; 12:2436-49. [PMID: 20406297 DOI: 10.1111/j.1462-2920.2010.02217.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The high complexity of naturally occurring microbial communities is the major drawback limiting the study of these important biological systems. In this study, a comparison between pure cultures of Pseudomonas reinekei sp. strain MT1 and stable community cultures composed of MT1 plus the addition of Achromobacter xylosoxidans strain MT3 (in a steady-state proportion 9:1) was used as a model system to study bacterial interactions that take place under simultaneous chemical and oxidative stress. Both are members of a real community isolated from a polluted sediment by enrichment in 4-chlorosalicylate (4CS). The analysis of dynamic states was carried out at the proteome, metabolic profile and population dynamic level. Differential protein expression was evaluated under exposure to 4CS and high concentrations of toxic intermediates (4-chlorocatechol and protoanemonin), including proteins from several functional groups and particularly enzymes of aromatic degradation pathways and outer membrane proteins. Remarkably, 4CS addition generated a strong oxidative stress response in pure strain MT1 culture led by alkyl hydroperoxide reductase, while the community showed an enhanced central metabolism response, where A. xylosoxidans MT3 helped to prevent toxic intermediate accumulation. A significant change in the outer membrane composition of P. reinekei MT1 was observed during the chemical stress caused by 4CS and in the presence of A. xylosoxidans MT3, highlighting the expression of the major outer membrane protein OprF, tightly correlated to 4CC concentration profile and its potential detoxification role.
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21
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Lykidis A, Pérez-Pantoja D, Ledger T, Mavromatis K, Anderson IJ, Ivanova NN, Hooper SD, Lapidus A, Lucas S, González B, Kyrpides NC. The complete multipartite genome sequence of Cupriavidus necator JMP134, a versatile pollutant degrader. PLoS One 2010; 5:e9729. [PMID: 20339589 PMCID: PMC2842291 DOI: 10.1371/journal.pone.0009729] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2009] [Accepted: 02/17/2010] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Cupriavidus necator JMP134 is a Gram-negative beta-proteobacterium able to grow on a variety of aromatic and chloroaromatic compounds as its sole carbon and energy source. METHODOLOGY/PRINCIPAL FINDINGS Its genome consists of four replicons (two chromosomes and two plasmids) containing a total of 6631 protein coding genes. Comparative analysis identified 1910 core genes common to the four genomes compared (C. necator JMP134, C. necator H16, C. metallidurans CH34, R. solanacearum GMI1000). Although secondary chromosomes found in the Cupriavidus, Ralstonia, and Burkholderia lineages are all derived from plasmids, analyses of the plasmid partition proteins located on those chromosomes indicate that different plasmids gave rise to the secondary chromosomes in each lineage. The C. necator JMP134 genome contains 300 genes putatively involved in the catabolism of aromatic compounds and encodes most of the central ring-cleavage pathways. This strain also shows additional metabolic capabilities towards alicyclic compounds and the potential for catabolism of almost all proteinogenic amino acids. This remarkable catabolic potential seems to be sustained by a high degree of genetic redundancy, most probably enabling this catabolically versatile bacterium with different levels of metabolic responses and alternative regulation necessary to cope with a challenging environment. From the comparison of Cupriavidus genomes, it is possible to state that a broad metabolic capability is a general trait for Cupriavidus genus, however certain specialization towards a nutritional niche (xenobiotics degradation, chemolithoautotrophy or symbiotic nitrogen fixation) seems to be shaped mostly by the acquisition of "specialized" plasmids. CONCLUSIONS/SIGNIFICANCE The availability of the complete genome sequence for C. necator JMP134 provides the groundwork for further elucidation of the mechanisms and regulation of chloroaromatic compound biodegradation.
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Affiliation(s)
- Athanasios Lykidis
- Department of Energy (DOE)-Joint Genome Institute, Walnut Creek, California, United States of America.
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22
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Pérez-Pantoja D, Donoso RA, Sánchez MA, González B. Genuine genetic redundancy in maleylacetate-reductase-encoding genes involved in degradation of haloaromatic compounds by Cupriavidus necator JMP134. Microbiology (Reading) 2009; 155:3641-3651. [DOI: 10.1099/mic.0.032086-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Maleylacetate reductases (MAR) are required for biodegradation of several substituted aromatic compounds. To date, the functionality of two MAR-encoding genes (tfdF
I and tfdF
II) has been reported in Cupriavidus necator JMP134(pJP4), a known degrader of aromatic compounds. These two genes are located in tfd gene clusters involved in the turnover of 2,4-dichlorophenoxyacetate (2,4-D) and 3-chlorobenzoate (3-CB). The C. necator JMP134 genome comprises at least three other genes that putatively encode MAR (tcpD, hqoD and hxqD), but confirmation of their functionality and their role in the catabolism of haloaromatic compounds has not been assessed. RT-PCR expression analyses of C. necator JMP134 cells exposed to 2,4-D, 3-CB, 2,4,6-trichlorophenol (2,4,6-TCP) or 4-fluorobenzoate (4-FB) showed that tfdF
I and tfdF
II are induced by haloaromatics channelled to halocatechols as intermediates. In contrast, 2,4,6-TCP only induces tcpD, and any haloaromatic compounds tested did not induce hxqD and hqoD. However, the tcpD, hxqD and hqoD gene products showed MAR activity in cell extracts and provided the MAR function for 2,4-D catabolism when heterologously expressed in MAR-lacking strains. Growth tests for mutants of the five MAR-encoding genes in strain JMP134 showed that none of these genes is essential for degradation of the tested compounds. However, the role of tfdF
I/tfdF
II and tcpD genes in the expression of MAR activity during catabolism of 2,4-D and 2,4,6-TCP, respectively, was confirmed by enzyme activity tests in mutants. These results reveal a striking example of genetic redundancy in the degradation of aromatic compounds.
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Affiliation(s)
- Danilo Pérez-Pantoja
- Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Millennium Nucleus on Microbial Ecology and Environmental Microbiology and Biotechnology, NM-EMBA, Center for Advanced Studies in Ecology and Biodiversity, CASEB, Santiago, Chile
| | - Raúl A. Donoso
- Facultad de Ingeniería y Ciencia, Universidad Adolfo Ibáñez, Santiago, Chile
| | - Miguel A. Sánchez
- Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Millennium Nucleus on Microbial Ecology and Environmental Microbiology and Biotechnology, NM-EMBA, Center for Advanced Studies in Ecology and Biodiversity, CASEB, Santiago, Chile
| | - Bernardo González
- Facultad de Ingeniería y Ciencia, Universidad Adolfo Ibáñez, Santiago, Chile
- Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Millennium Nucleus on Microbial Ecology and Environmental Microbiology and Biotechnology, NM-EMBA, Center for Advanced Studies in Ecology and Biodiversity, CASEB, Santiago, Chile
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Sentchilo V, Czechowska K, Pradervand N, Minoia M, Miyazaki R, van der Meer JR. Intracellular excision and reintegration dynamics of the ICEclcgenomic island ofPseudomonas knackmussiisp. strain B13. Mol Microbiol 2009; 72:1293-306. [DOI: 10.1111/j.1365-2958.2009.06726.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Characterization of a gene cluster involved in 4-chlorocatechol degradation by Pseudomonas reinekei MT1. J Bacteriol 2009; 191:4905-15. [PMID: 19465655 DOI: 10.1128/jb.00331-09] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas reinekei MT1 has previously been reported to degrade 4- and 5-chlorosalicylate by a pathway with 4-chlorocatechol, 3-chloromuconate, 4-chloromuconolactone, and maleylacetate as intermediates, and a gene cluster channeling various salicylates into an intradiol cleavage route has been reported. We now report that during growth on 5-chlorosalicylate, besides a novel (chloro)catechol 1,2-dioxygenase, C12O(ccaA), a novel (chloro)muconate cycloisomerase, MCI(ccaB), which showed features not yet reported, was induced. This cycloisomerase, which was practically inactive with muconate, evolved for the turnover of 3-substituted muconates and transforms 3-chloromuconate into equal amounts of cis-dienelactone and protoanemonin, suggesting that it is a functional intermediate between chloromuconate cycloisomerases and muconate cycloisomerases. The corresponding genes, ccaA (C12O(ccaA)) and ccaB (MCI(ccaB)), were located in a 5.1-kb genomic region clustered with genes encoding trans-dienelactone hydrolase (ccaC) and maleylacetate reductase (ccaD) and a putative regulatory gene, ccaR, homologous to regulators of the IclR-type family. Thus, this region includes genes sufficient to enable MT1 to transform 4-chlorocatechol to 3-oxoadipate. Phylogenetic analysis showed that C12O(ccaA) and MCI(ccaB) are only distantly related to previously described catechol 1,2-dioxygenases and muconate cycloisomerases. Kinetic analysis indicated that MCI(ccaB) and the previously identified C12O(salD), rather than C12O(ccaA), are crucial for 5-chlorosalicylate degradation. Thus, MT1 uses enzymes encoded by a completely novel gene cluster for degradation of chlorosalicylates, which, together with a gene cluster encoding enzymes for channeling salicylates into the ortho-cleavage pathway, form an effective pathway for 4- and 5-chlorosalicylate mineralization.
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Pérez-Pantoja D, De la Iglesia R, Pieper DH, González B. Metabolic reconstruction of aromatic compounds degradation from the genome of the amazing pollutant-degrading bacteriumCupriavidus necatorJMP134. FEMS Microbiol Rev 2008; 32:736-94. [DOI: 10.1111/j.1574-6976.2008.00122.x] [Citation(s) in RCA: 178] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Kiesel B, Müller R, Kleinsteuber R. Adaptative Potential of Alkaliphilic Bacteria towards Chloroaromatic Substrates Assessed by agfp-tagged 2,4-D Degradation Plasmid. Eng Life Sci 2007. [DOI: 10.1002/elsc.200720200] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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Mazzoli R, Pessione E, Giuffrida MG, Fattori P, Barello C, Giunta C, Lindley ND. Degradation of aromatic compounds by Acinetobacter radioresistens S13: growth characteristics on single substrates and mixtures. Arch Microbiol 2007; 188:55-68. [PMID: 17483933 DOI: 10.1007/s00203-007-0223-z] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2006] [Revised: 01/22/2007] [Accepted: 02/07/2007] [Indexed: 11/26/2022]
Abstract
Acinetobacter radioresistens S13 is able to grow on phenol or benzoate as the sole carbon and energy source: both these compounds are catabolized through the beta-ketoadipate pathway. Genes encoding the catabolic enzymes for degradation of aromatic compounds are localized on A. radioresistens S13 chromosome and organized in, at least, two distinct sets, one for benzoate degradation and another for phenol catabolism. In the present study, the growth and biodegradation kinetics for benzoate and phenol, and an easily metabolized substrate (acetate) were established. Benzoate was degraded slower and supports a less rapid and efficient growth than either acetate or phenol. A combined transcript-proteomic analysis of some of the major catabolic genes and their products nonetheless has shown that benzoate induces the expression of both benzoate and phenol catabolic operons. This result was confirmed by the fact that benzoate-acclimatized bacteria were rapidly able to degrade phenol too. Finally, the growth and biodegradation kinetics for different mixtures of acetate, benzoate and phenol were determined. Results indicate that a hierarchy of substrate utilization, benzoate > acetate > phenol, occurred: benzoate was the preferred substrate, despite its lower growth and biodegradation parameters. Hypotheses explaining these unusual metabolic features of A. radioresistens S13 are discussed.
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Affiliation(s)
- Roberto Mazzoli
- Dipartimento di Biologia Animale e dell'Uomo, Università di Torino, Via Accademia Albertina 13, 10123 Torino, Italy.
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Endo R, Ohtsubo Y, Tsuda M, Nagata Y. Identification and characterization of genes encoding a putative ABC-type transporter essential for utilization of gamma-hexachlorocyclohexane in Sphingobium japonicum UT26. J Bacteriol 2007; 189:3712-20. [PMID: 17369300 PMCID: PMC1913331 DOI: 10.1128/jb.01883-06] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Sphingobium japonicum UT26 utilizes gamma-hexachlorocyclohexane (gamma-HCH) as its sole source of carbon and energy. In our previous studies, we cloned and characterized genes encoding enzymes for the conversion of gamma-HCH to beta-ketoadipate in UT26. In this study, we analyzed a mutant obtained by transposon mutagenesis and identified and characterized new genes encoding a putative ABC-type transporter essential for the utilization of gamma-HCH in strain UT26. This putative ABC transporter consists of four components, permease, ATPase, periplasmic protein, and lipoprotein, encoded by linK, linL, linM, and linN, respectively. Mutation and complementation analyses indicated that all the linKLMN genes are required, probably as a set, for gamma-HCH utilization in UT26. Furthermore, the mutant cells deficient in this putative ABC transporter showed (i) higher gamma-HCH degradation activity and greater accumulation of the toxic dead-end product 2,5-dichlorophenol (2,5-DCP), (ii) higher sensitivity to 2,5-DCP itself, and (iii) higher permeability of hydrophobic compounds than the wild-type cells. These results strongly suggested that LinKLMN are involved in gamma-HCH utilization by controlling membrane hydrophobicity. This study clearly demonstrated that a cellular factor besides catabolic enzymes and transcriptional regulators is essential for utilization of xenobiotic compounds in bacterial cells.
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Affiliation(s)
- Ryo Endo
- Department of Environmental Life Sciences, Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Sendai 980-8577, Japan
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Sánchez MA, González B. Genetic characterization of 2,4,6-trichlorophenol degradation in Cupriavidus necator JMP134. Appl Environ Microbiol 2007; 73:2769-76. [PMID: 17322325 PMCID: PMC1892852 DOI: 10.1128/aem.02584-06] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The degradation pathway of 2,4,6-trichlorophenol (2,4,6-TCP), a hazardous pollutant, in the aerobic bacterium Cupriavidus necator JMP134(pJP4) (formerly Ralstonia eutropha JMP134) is encoded by the tcp genes. These genes are located in a genetic context, tcpRXABCYD, which resembles a putative catabolic operon. In this work, these gene sequences were individually disrupted and mutant strains were evaluated for their ability to grow on or degrade 2,4,6-TCP. The tcpX and tcpA mutants completely failed to degrade this compound. Although the tcpC mutant was also unable to grow on 2,4,6-TCP, it still transformed this chlorophenol to 6-chlorohydroquinol. In contrast, the tcpD mutant grew on 2,4,6-TCP, suggesting the presence of additional maleylacetate reductase-encoding genes. Five other open reading frames encoding maleylacetate reductases, in addition to the tcpD gene, were found in the genome of C. necator, and two of them provide this function in the tcpD mutant. The tcpR gene, encoding a putative LysR-type transcriptional regulator, was disrupted, and this mutant strain completely failed to grow on 2,4,6-TCP. Transcriptional fusion studies demonstrated that TcpR activates the expression of the tcp genes, responding specifically to 2,4,6-TCP. The transcriptional start of the tcp operon was mapped, and a putative sigma(70)-type promoter was identified.
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Affiliation(s)
- M A Sánchez
- Laboratorio de Microbiología, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla 114-D, Santiago, Chile
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Nestler H, Kiesel B, Kaschabek SR, Mau M, Schlömann M, Balcke GU. Biodegradation of chlorobenzene under hypoxic and mixed hypoxic-denitrifying conditions. Biodegradation 2007; 18:755-67. [PMID: 17279449 DOI: 10.1007/s10532-007-9104-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2006] [Accepted: 01/16/2007] [Indexed: 10/23/2022]
Abstract
Pseudomonas veronii strain UFZ B549, Acidovorax facilis strain UFZ B530, and a community of indigenous groundwater bacteria, adapted to oxygen limitation, were cultivated on chlorobenzene and its metabolites 2-chloro-cis,cis-muconate and acetate/succinate under hypoxic and denitrifying conditions. Highly sensitive approaches were used to maintain defined low oxygen partial pressures in an oxygen-re-supplying headspace. With low amounts of oxygen available all cultures converted chlorobenzene, though the pure strains accumulated 3-chlorocatechol and 2-chloro-cis,cis-muconate as intermediates. Under strictly anoxic conditions no chlorobenzene transformation was observed, while 2-chloro-cis,cis-muconate, the fission product of oxidative ring cleavage, was readily degraded by the investigated chlorobenzene-degrading cultures at the expense of nitrate as terminal electron acceptor. Hence, we conclude that oxygen is an obligatory reactant for initial activation of chlorobenzene and fission of the aromatic ring, but it can be partially replaced by nitrate in respiration. The tendency to denitrify in the presence of oxygen during growth on chlorobenzene appeared to depend on the oxygen availability and the efficiency to metabolize chlorobenzene under oxygen limitation, which is largely regulated by the activity of the intradiol ring fission dioxygenase. Permanent cultivation of a groundwater consortium under reduced oxygen levels resulted in enrichment of a community almost exclusively composed of members of the beta-Proteobacteria and Bacteroidetes. Thus, it is deduced that these strains can still maintain high activities of oxygen-requiring enzymes that allow for efficient CB transformation under hypoxic conditions.
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Affiliation(s)
- Holger Nestler
- Department of Hydrogeology, Helmholtz Centre for Environmental Research-UFZ, Theodor-Lieser-Strasse 4, D-06120 Halle (Saale), Germany.
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Larraín-Linton J, De la Iglesia R, Melo F, González B. Molecular and population analyses of a recombination event in the catabolic plasmid pJP4. J Bacteriol 2006; 188:6793-801. [PMID: 16980481 PMCID: PMC1595507 DOI: 10.1128/jb.00869-06] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cupriavidus necator JMP134(pJP4) harbors a catabolic plasmid, pJP4, which confers the ability to grow on chloroaromatic compounds. Repeated growth on 3-chlorobenzoate (3-CB) results in selection of a recombinant strain, which degrades 3-CB better but no longer grows on 2,4-dichlorophenoxyacetate (2,4-D). We have previously proposed that this phenotype is due to a double homologous recombination event between inverted repeats of the multicopies of this plasmid within the cell. One recombinant form of this plasmid (pJP4-F3) explains this phenotype, since it harbors two copies of the chlorocatechol degradation tfd gene clusters, which are essential to grow on 3-CB, but has lost the tfdA gene, encoding the first step in degradation of 2,4-D. The other recombinant plasmid (pJP4-FM) should harbor two copies of the tfdA gene but no copies of the tfd gene clusters. A molecular analysis using a multiplex PCR approach to distinguish the wild-type plasmid pJP4 from its two recombinant forms, was carried out. Expected PCR products confirming this recombination model were found and sequenced. Few recombinant plasmid forms in cultures grown in several carbon sources were detected. Kinetic studies indicated that cells containing the recombinant plasmid pJP4-FM were not selectable by sole carbon source growth pressure, whereas those cells harboring recombinant plasmid pJP4-F3 were selected upon growth on 3-CB. After 12 days of repeated growth on 3-CB, the complete plasmid population in C. necator JMP134 apparently corresponds to this form. However, wild-type plasmid forms could be recovered after growing this culture on 2,4-D, indicating that different plasmid forms can be found in C. necator JMP134 at the population level.
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Affiliation(s)
- Juanita Larraín-Linton
- Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla 114-D, Santiago, Chile
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Liao Y, Zhou X, Yu J, Cao Y, Li X, Kuai B. The key role of chlorocatechol 1,2-dioxygenase in phytoremoval and degradation of catechol by transgenic Arabidopsis. PLANT PHYSIOLOGY 2006; 142:620-8. [PMID: 16935988 PMCID: PMC1586047 DOI: 10.1104/pp.106.085936] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2006] [Accepted: 08/21/2006] [Indexed: 05/08/2023]
Abstract
Transgenic exploitation of bacterial degradative genes in plants has been considered a favorable strategy for degrading organic pollutants in the environment. The aromatic ring characteristic of these pollutants is mainly responsible for their recalcitrance to degradation. In this study, a Plesiomonas-derived chlorocatechol 1,2-dioxygenase (TfdC) gene (tfdC), capable of cleaving the aromatic ring, was introduced into Arabidopsis (Arabidopsis thaliana). Morphology and growth of transgenic plants are indistinguishable from those of wild-type plants. In contrast, they show significantly enhanced tolerances to catechol. Transgenic plants also exhibit strikingly higher capabilities of removing catechol from their media and high efficiencies of converting catechol to cis,cis-muconic acid. As far-less-than-calculated amounts of cis,cis-muconic acid were accumulated within the transgenic plants, existence of endogenous TfdD- and TfdE-like activities was postulated and, subsequently, putative orthologs of bacterial tfdD and tfdE were detected in Arabidopsis. However, no TfdC activity and no putative orthologs of either tfdC or tfdF were identified. This work indicates that the TfdC activity, conferred by tfdC in transgenic Arabidopsis, is a key requirement for phytoremoval and degradation of catechol, and also suggests that microbial degradative genes may be transgenically exploited in plants for bioremediation of aromatic pollutants in the environment.
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Affiliation(s)
- Yang Liao
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200433, China
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Ledger T, Pieper DH, González B. Chlorophenol hydroxylases encoded by plasmid pJP4 differentially contribute to chlorophenoxyacetic acid degradation. Appl Environ Microbiol 2006; 72:2783-92. [PMID: 16597983 PMCID: PMC1448979 DOI: 10.1128/aem.72.4.2783-2792.2006] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Phenoxyalkanoic compounds are used worldwide as herbicides. Cupriavidus necator JMP134(pJP4) catabolizes 2,4-dichlorophenoxyacetate (2,4-D) and 4-chloro-2-methylphenoxyacetate (MCPA), using tfd functions carried on plasmid pJP4. TfdA cleaves the ether bonds of these herbicides to produce 2,4-dichlorophenol (2,4-DCP) and 4-chloro-2-methylphenol (MCP), respectively. These intermediates can be degraded by two chlorophenol hydroxylases encoded by the tfdB(I) and tfdB(II) genes to produce the respective chlorocatechols. We studied the specific contribution of each of the TfdB enzymes to the 2,4-D/MCPA degradation pathway. To accomplish this, the tfdB(I) and tfdB(II) genes were independently inactivated, and growth on each chlorophenoxyacetate and total chlorophenol hydroxylase activity were measured for the mutant strains. The phenotype of these mutants shows that both TfdB enzymes are used for growth on 2,4-D or MCPA but that TfdB(I) contributes to a significantly higher extent than TfdB(II). Both enzymes showed similar specificity profiles, with 2,4-DCP, MCP, and 4-chlorophenol being the best substrates. An accumulation of chlorophenol was found to inhibit chlorophenoxyacetate degradation, and inactivation of the tfdB genes enhanced the toxic effect of 2,4-DCP on C. necator cells. Furthermore, increased chlorophenol production by overexpression of TfdA also had a negative effect on 2,4-D degradation by C. necator JMP134 and by a different host, Burkholderia xenovorans LB400, harboring plasmid pJP4. The results of this work indicate that codification and expression of the two tfdB genes in pJP4 are important to avoid toxic accumulations of chlorophenols during phenoxyacetic acid degradation and that a balance between chlorophenol-producing and chlorophenol-consuming reactions is necessary for growth on these compounds.
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Affiliation(s)
- T Ledger
- Laboratorio de Microbiología, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla 114-D, Santiago, Chile
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el Fantroussi S, Agathos SN, Pieper DH, Witzig R, Cámara B, Gabriel-Jürgens L, Junca H, Zanaroli G, Fava F, Pérez-Jiménez JR, Young LY, Hamonts K, Lookman R, Maesen M, Diels L, Dejonghe W, Dijk J, Springael D. Biological Assessment and Remediation of Contaminated Sediments. ACTA ACUST UNITED AC 2006. [DOI: 10.1007/978-1-4020-4959-0_5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/21/2023]
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Lang GH, Ogawa N, Tanaka Y, Fujii T, Fulthorpe RR, Fukuda M, Miyashita K. Two kinds of chlorocatechol 1,2-dioxygenase from 2,4-dichlorophenoxyacetate-degrading Sphingomonas sp. strain TFD44. Biochem Biophys Res Commun 2005; 332:941-8. [PMID: 15916749 DOI: 10.1016/j.bbrc.2005.05.045] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2005] [Accepted: 05/10/2005] [Indexed: 11/23/2022]
Abstract
Two kinds of chlorocatechol 1,2-dioxygenase (CCD), TfdC and TfdC2 were detected in Sphingomonas sp. strain TFD44. These two CCDs could be simultaneously synthesized in TFD44 during its growth with 2,4-D as the sole carbon and energy sources. The apparent subunit molecular masses of TfdC and TfdC2 estimated by SDS-PAGE analysis were 33.8 and 33.1 kDa, respectively. The genes encoding the two CCDs were cloned and expressed in Escherichia coli. The two purified CCDs showed broad substrate specificities but had different specificity patterns. TfdC showed the highest specificity constant for 3-chlorocatechol and TfdC2 showed the highest specificity constant for 3,5-dichlorocatechol. The substrate specificity difference seemed to correlate with the alternation of amino acid supposed to be involved in the interaction with substrates. Whereas phylogenetic analysis indicated that the CCDs of Sphingomonas constitute a distinctive group among Gram-negative bacteria, TfdC and TfdC2 of TFD44 have divergently evolved in terms of their substrate specificity.
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Affiliation(s)
- Gang-hua Lang
- National Institute for Agro-Environmental Sciences, 3-1-3 Kan-nondai, Tsukuba, Ibaraki 305-8604, Japan
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Pieper DH. Aerobic degradation of polychlorinated biphenyls. Appl Microbiol Biotechnol 2004; 67:170-91. [PMID: 15614564 DOI: 10.1007/s00253-004-1810-4] [Citation(s) in RCA: 226] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2004] [Revised: 10/10/2004] [Accepted: 10/19/2004] [Indexed: 10/26/2022]
Abstract
The microbial degradation of polychlorinated biphenyls (PCBs) has been extensively studied in recent years. The genetic organization of biphenyl catabolic genes has been elucidated in various groups of microorganisms, their structures have been analyzed with respect to their evolutionary relationships, and new information on mobile elements has become available. Key enzymes, specifically biphenyl 2,3-dioxygenases, have been intensively characterized, structure/sequence relationships have been determined and enzymes optimized for PCB transformation. However, due to the complex metabolic network responsible for PCB degradation, optimizing degradation by single bacterial species is necessarily limited. As PCBs are usually not mineralized by biphenyl-degrading organisms, and cometabolism can result in the formation of toxic metabolites, the degradation of chlorobenzoates has received special attention. A broad set of bacterial strategies to degrade chlorobenzoates has recently been elucidated, including new pathways for the degradation of chlorocatechols as central intermediates of various chloroaromatic catabolic pathways. To optimize PCB degradation in the environment beyond these metabolic limitations, enhancing degradation in the rhizosphere has been suggested, in addition to the application of surfactants to overcome bioavailability barriers. However, further research is necessary to understand the complex interactions between soil/sediment, pollutant, surfactant and microorganisms in different environments.
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Affiliation(s)
- Dietmar H Pieper
- Department of Environmental Microbiology, German Research Center for Biotechnology, Mascheroder Weg 1, 38124, Braunschweig, Germany.
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Thiel M, Kaschabek SR, Gröning J, Mau M, Schlömann M. Two unusual chlorocatechol catabolic gene clusters in Sphingomonas sp. TFD44. Arch Microbiol 2004; 183:80-94. [PMID: 15688254 DOI: 10.1007/s00203-004-0748-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2004] [Revised: 10/26/2004] [Accepted: 11/03/2004] [Indexed: 11/29/2022]
Abstract
The genes responsible for the degradation of 2,4-dichlorophenoxyacetate (2,4-D) by alpha-Proteobacteria have previously been difficult to detect by using gene probes or polymerase chain reaction (PCR) primers. PCR products of the chlorocatechol 1,2-dioxygenase gene, tfdC, now allowed cloning of two chlorocatechol gene clusters from the Sphingomonas sp. strain TFD44. Sequence characterization showed that the first cluster, tfdD,RFCE, comprises all the genes necessary for the conversion of 3,5-dichlorocatechol to 3-oxoadipate, including a presumed regulatory gene, tfdR, of the LysR-type family. The second gene cluster, tfdC2E2F2, is incomplete and appears to lack a chloromuconate cycloisomerase gene and a regulatory gene. Purification and N-terminal sequencing of selected enzymes suggests that at least representatives of both gene clusters (TfdD of cluster 1 and TfdC2 of cluster 2) are induced during the growth of strain TFD44 with 2,4-D. A mutant constructed to contain an insertion in the chloromuconate cycloisomerase gene tfdD still was able to grow with 2,4-D, but more slowly and with a longer lag phase. This, and the detection of additional activity peaks during protein purification suggest that strain TFD44 harbors at least another chloromuconate cycloisomerase gene. The sequence of the tfdCE region was almost identical to that of a partially characterized chlorocatechol catabolic gene cluster of Sphingomonas herbicidovorans MH, whereas the sequence of the tfdC2E2F2 cluster was different. The similarity of the predicted proteins of the tfdD,RFCE and tfdC2E2F2 clusters to known sequences of other Proteobacteria in the database ranged from 42 to 61% identical positions for the first cluster and from 45.5 to 58% identical positions for the second cluster. Between both clusters, the similarities of their predicted proteins ranged from 44.5 to 64% identical positions. Thus, both clusters (together with those of S. herbicidovorans MH) represent deep-branching lines in the respective dendrograms, and the sequence information will help future primer design for the detection of corresponding genes in the environment.
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Affiliation(s)
- Monika Thiel
- Interdisciplinary Ecological Center, Technische Universität Bergakademie Freiberg, Leipziger Strasse 29, 09599 Freiberg, Germany
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Gust B, Chandra G, Jakimowicz D, Yuqing T, Bruton CJ, Chater KF. Lambda red-mediated genetic manipulation of antibiotic-producing Streptomyces. ADVANCES IN APPLIED MICROBIOLOGY 2004; 54:107-28. [PMID: 15251278 DOI: 10.1016/s0065-2164(04)54004-2] [Citation(s) in RCA: 210] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Bertolt Gust
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Colney, Norwich, NR4 7UH, United Kingdom
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Trefault N, De la Iglesia R, Molina AM, Manzano M, Ledger T, Pérez-Pantoja D, Sánchez MA, Stuardo M, González B. Genetic organization of the catabolic plasmid pJP4 from Ralstonia eutropha JMP134 (pJP4) reveals mechanisms of adaptation to chloroaromatic pollutants and evolution of specialized chloroaromatic degradation pathways. Environ Microbiol 2004; 6:655-68. [PMID: 15186344 DOI: 10.1111/j.1462-2920.2004.00596.x] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ralstonia eutropha JMP134 (pJP4) is a useful model for the study of bacterial degradation of substituted aromatic pollutants. Several key degrading capabilities, encoded by tfd genes, are located in the 88 kb, self-transmissible, IncP-1 beta plasmid pJP4. The complete sequence of the 87,688 nucleotides of pJP4, encoding 83 open reading frames (ORFs), is reported. Most of the coding sequence corresponds to a well-conserved IncP-1 beta backbone and the previously reported tfd genes. In addition, we found hypothetical proteins putatively involved in the transport of aromatic compounds and short-chain fatty acid oxidation. ORFs related to mobile elements, including the Tn501-encoded mercury resistance determinants, an IS1071-based composite transposon and a cryptic class II transposon, are also present in pJP4. These mobile elements are inefficient in transposition and are located in two regions of pJP4 that are rich in remnants of lateral gene transfer events. pJP4 plasmid was able to capture chromosomal genes and form hybrid plasmids with the IncP-1 alpha plasmid RP4. These observations are integrated into a model for the evolution of pJP4, which reveals mechanisms of bacterial adaptation to degrade pollutants.
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MESH Headings
- Adaptation, Physiological
- Base Composition
- Biodegradation, Environmental
- Cupriavidus necator/genetics
- Cupriavidus necator/metabolism
- DNA Transposable Elements
- DNA, Bacterial/chemistry
- DNA, Bacterial/isolation & purification
- Drug Resistance, Bacterial/genetics
- Environmental Pollutants/metabolism
- Gene Order
- Gene Transfer, Horizontal
- Genes, Bacterial
- Hydrocarbons, Aromatic/metabolism
- Mercury Compounds/toxicity
- Molecular Sequence Data
- Open Reading Frames
- Operon
- Plasmids/genetics
- Recombination, Genetic
- Sequence Analysis, DNA
- Transcription, Genetic
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Affiliation(s)
- N Trefault
- Laboratorio de Microbiología, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla 114-D, and Millennium Institute for Fundamental and Applied Biology, Santiago, Chile
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Junca H, Pieper DH. Functional gene diversity analysis in BTEX contaminated soils by means of PCR-SSCP DNA fingerprinting: comparative diversity assessment against bacterial isolates and PCR-DNA clone libraries. Environ Microbiol 2004; 6:95-110. [PMID: 14756875 DOI: 10.1046/j.1462-2920.2003.00541.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Developments in molecular biology based techniques have led to rapid and reliable tools to characterize microbial community structures and to monitor their dynamics under in situ conditions. However, there has been a distinct lack of emphasis on monitoring the functional diversity in the environment. Genes encoding catechol 2,3-dioxygenases (C23O), as key enzymes of various aerobic aromatic degradation pathways, were used as functional targets to assess the catabolic gene diversity in differentially BTEX contaminated environments by polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP). Site specific PCR-SSCP fingerprints were obtained, showing that gene diversity experienced shifts correlated to temporal changes and levels of contamination. PCR-SSCP enabled the recovery of predominant gene polymorphs, and results closely matched with the information retrieved from random sequencing of PCR-DNA clone libraries. A new method for isolating strains capable of growing on BTEX compounds was developed to diminish preselection or enrichment bias and to assess the function of predominant gene polymorphs. C23O abundance in isolates correlated with the levels of BTEX pollution in the soil samples analysed. Isolates harbouring C23O genes, identical to the gene polymorph predominant in all contaminated sites analysed, showed an unexpected benzene but not toluene mineralizing phenotype whereas isolates harbouring a C23O gene variant differing by a single point mutation and observed in highly polluted sites only, were capable, among some other isolates, to mineralize benzene and toluene, indicating a catabolically determined sharing of carbon sources on-site. The PCR-SSCP technique is thus a powerful tool for assessing the diversity of functional genes and the identification of predominant gene polymorphs in environmental samples as a prerequisite to understand the functioning of microbial communities.
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Affiliation(s)
- Howard Junca
- Department of Environmental Microbiology, GBF-German Research Centre for Biotechnology, Mascheroder Weg 1, D-38124 Braunschweig, Germany
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