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Iasakov T. Evolution End Classification of tfd Gene Clusters Mediating Bacterial Degradation of 2,4-Dichlorophenoxyacetic Acid (2,4-D). Int J Mol Sci 2023; 24:14370. [PMID: 37762674 PMCID: PMC10531765 DOI: 10.3390/ijms241814370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 09/11/2023] [Accepted: 09/16/2023] [Indexed: 09/29/2023] Open
Abstract
The tfd (tfdI and tfdII) are gene clusters originally discovered in plasmid pJP4 which are involved in the bacterial degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) via the ortho-cleavage pathway of chlorinated catechols. They share this activity, with respect to substituted catechols, with clusters tcb and clc. Although great effort has been devoted over nearly forty years to exploring the structural diversity of these clusters, their evolution has been poorly resolved to date, and their classification is clearly obsolete. Employing comparative genomic and phylogenetic approaches has revealed that all tfd clusters can be classified as one of four different types. The following four-type classification and new nomenclature are proposed: tfdI, tfdII, tfdIII and tfdIV(A,B,C). Horizontal gene transfer between Burkholderiales and Sphingomonadales provides phenomenal linkage between tfdI, tfdII, tfdIII and tfdIV type clusters and their mosaic nature. It is hypothesized that the evolution of tfd gene clusters proceeded within first (tcb, clc and tfdI), second (tfdII and tfdIII) and third (tfdIV(A,B,C)) evolutionary lineages, in each of which, the genes were clustered in specific combinations. Their clustering is discussed through the prism of hot spots and driving forces of various models, theories, and hypotheses of cluster and operon formation. Two hypotheses about series of gene deletions and displacements are also proposed to explain the structural variations across members of clusters tfdII and tfdIII, respectively. Taking everything into account, these findings reconstruct the phylogeny of tfd clusters, have delineated their evolutionary trajectories, and allow the contribution of various evolutionary processes to be assessed.
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Affiliation(s)
- Timur Iasakov
- Ufa Institute of Biology, Ufa Federal Research Centre, Russian Academy of Sciences, Prospekt Oktyabrya, 69, 450054 Ufa, Russia
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Alghuthaymi MA, Awad AM, Hassan HA. Isolation and Characterization a Novel Catabolic Gene Cluster Involved in Chlorobenzene Degradation in Haloalkaliphilic Alcanivorax sp. HA03. BIOLOGY 2022; 11:biology11050724. [PMID: 35625452 PMCID: PMC9138330 DOI: 10.3390/biology11050724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 05/05/2022] [Accepted: 05/06/2022] [Indexed: 11/16/2022]
Abstract
Chlorobenzene (CB) poses a serious risk to human health and the environment, and because of its low degradation rate by microorganisms, it persists in the environment. Some bacterial strains can use CB as growth substrates and their degradative pathways have evolved; very little is known about these pathways and the enzymes for CB degradation in high pH and salinity environments. Alcanivorax sp. HA03 was isolated from the extremely saline and alkaline site. HA03 has the capability to degrade benzene, toluene and chlorobenzene (CB). CB catabolic genes were isolated from HA03, which have a complete gene cluster comprising α and β subunits, ferredoxin and ferredoxin reductase (CBA1A2A3A4), as well as one gene-encoding enzyme for chlorocatechol 1,2-dioxygenase (CC12DOs). Based on the deduced amino acid sequence homology, the gene cluster was thought to be responsible for the upper and lower catabolic pathways of CB degradation. The CBA1A2A3A4 genes probably encoding a chlorobenzene dioxygenase was confirmed by expression during the growth on CB by RT-PCR. Heterologous expression revealed that CBA1A2A3A4 exhibited activity for CB transformation into 3-chlorocatechol, while CC12DOs catalyze 3-chlorocatechol, transforming it into 2-chloromucounate. SDS-PAGE analysis indicated that the sizes of CbA1 and (CC12DOs) gene products were 51.8, 27.5 kDa, respectively. Thus, Alcanivorax sp. HA03 constitutes the first bacterial strain described in the metabolic pathway of CB degradation under high pH and salinity conditions. This finding may have obvious potential for the bioremediation of CB in both highly saline and alkaline contaminated sites.
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Affiliation(s)
- Mousa A. Alghuthaymi
- Biology Department, Science and Humanities College, Shaqra University, Alquwayiyah 11726, Saudi Arabia;
| | - Ahmed M. Awad
- Department of Environmental Biotechnology, Genetic Engineering and Biotechnology Research Institute, University of Sadat City, Sadat City 32897, Egypt;
| | - Hamdy A. Hassan
- Biology Department, Science and Humanities College, Shaqra University, Alquwayiyah 11726, Saudi Arabia;
- Department of Environmental Biotechnology, Genetic Engineering and Biotechnology Research Institute, University of Sadat City, Sadat City 32897, Egypt;
- Correspondence:
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Magnoli K, Carranza CS, Aluffi ME, Magnoli CE, Barberis CL. Herbicides based on 2,4-D: its behavior in agricultural environments and microbial biodegradation aspects. A review. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:38501-38512. [PMID: 32770339 DOI: 10.1007/s11356-020-10370-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 08/03/2020] [Indexed: 06/11/2023]
Abstract
One of the main herbicides used in the agricultural environments is 2,4-dichlorophenoxyacetic acid (2,4-D). It is a synthetic plant hormone auxin employed in many crops including rice, wheat, sorghum, sugar cane, and corn to control wide leaf weeds. The indiscriminate use of pesticides can produce numerous damages to the environment. Therefore, this review has the objective to provide an overview on the main characteristics of the herbicides based on 2,4-D, mostly on the role of microorganisms in its degradation and its main degradation metabolite, 2,4- dichlorophenol (2,4-DCP). The remediation processes carried out by microorganisms are advantageous to avoid the pollution of the environment as well as to safeguard the population health.
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Affiliation(s)
- Karen Magnoli
- Instituto de Investigación en Micología y Micotoxicología (IMICO-CONICET). Departamento de Microbiología e Inmunología, Facultad de Ciencias Exactas, Físico, Químicas y Naturales, Universidad Nacional de Río Cuarto, Ruta Nacional N° 36 Km 601, 5800, Río Cuarto, Córdoba, Argentina
| | - Cecilia Soledad Carranza
- Instituto de Investigación en Micología y Micotoxicología (IMICO-CONICET). Departamento de Microbiología e Inmunología, Facultad de Ciencias Exactas, Físico, Químicas y Naturales, Universidad Nacional de Río Cuarto, Ruta Nacional N° 36 Km 601, 5800, Río Cuarto, Córdoba, Argentina
| | - Melisa Eglé Aluffi
- Instituto de Investigación en Micología y Micotoxicología (IMICO-CONICET). Departamento de Microbiología e Inmunología, Facultad de Ciencias Exactas, Físico, Químicas y Naturales, Universidad Nacional de Río Cuarto, Ruta Nacional N° 36 Km 601, 5800, Río Cuarto, Córdoba, Argentina
| | - Carina Elizabeth Magnoli
- Instituto de Investigación en Micología y Micotoxicología (IMICO-CONICET). Departamento de Microbiología e Inmunología, Facultad de Ciencias Exactas, Físico, Químicas y Naturales, Universidad Nacional de Río Cuarto, Ruta Nacional N° 36 Km 601, 5800, Río Cuarto, Córdoba, Argentina
| | - Carla Lorena Barberis
- Instituto de Investigación en Micología y Micotoxicología (IMICO-CONICET). Departamento de Microbiología e Inmunología, Facultad de Ciencias Exactas, Físico, Químicas y Naturales, Universidad Nacional de Río Cuarto, Ruta Nacional N° 36 Km 601, 5800, Río Cuarto, Córdoba, Argentina.
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Serbent MP, Rebelo AM, Pinheiro A, Giongo A, Tavares LBB. Biological agents for 2,4-dichlorophenoxyacetic acid herbicide degradation. Appl Microbiol Biotechnol 2019; 103:5065-5078. [DOI: 10.1007/s00253-019-09838-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 03/12/2019] [Accepted: 04/07/2019] [Indexed: 12/22/2022]
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Westphal AH, Tischler D, Heinke F, Hofmann S, Gröning JAD, Labudde D, van Berkel WJH. Pyridine Nucleotide Coenzyme Specificity of p-Hydroxybenzoate Hydroxylase and Related Flavoprotein Monooxygenases. Front Microbiol 2018; 9:3050. [PMID: 30631308 PMCID: PMC6315137 DOI: 10.3389/fmicb.2018.03050] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 11/27/2018] [Indexed: 12/03/2022] Open
Abstract
p-Hydroxybenzoate hydroxylase (PHBH; EC 1.14.13.2) is a microbial group A flavoprotein monooxygenase that catalyzes the ortho-hydroxylation of 4-hydroxybenzoate to 3,4-dihydroxybenzoate with the stoichiometric consumption of NAD(P)H and oxygen. PHBH and related enzymes lack a canonical NAD(P)H-binding domain and the way they interact with the pyridine nucleotide coenzyme has remained a conundrum. Previously, we identified a surface exposed protein segment of PHBH from Pseudomonas fluorescens involved in NADPH binding. Here, we report the first amino acid sequences of NADH-preferring PHBHs and a phylogenetic analysis of putative PHBHs identified in currently available bacterial genomes. It was found that PHBHs group into three clades consisting of NADPH-specific, NAD(P)H-dependent and NADH-preferring enzymes. The latter proteins frequently occur in Actinobacteria. To validate the results, we produced several putative PHBHs in Escherichia coli and confirmed their predicted coenzyme preferences. Based on phylogeny, protein energy profiling and lifestyle of PHBH harboring bacteria we propose that the pyridine nucleotide coenzyme specificity of PHBH emerged through adaptive evolution and that the NADH-preferring enzymes are the older versions of PHBH. Structural comparison and distance tree analysis of group A flavoprotein monooxygenases indicated that a similar protein segment as being responsible for the pyridine nucleotide coenzyme specificity of PHBH is involved in determining the pyridine nucleotide coenzyme specificity of the other group A members.
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Affiliation(s)
- Adrie H Westphal
- Laboratory of Biochemistry, Wageningen University and Research, Wageningen, Netherlands
| | - Dirk Tischler
- Interdisziplinäres Ökologisches Zentrum, Technische Universität Bergakademie Freiberg, Freiberg, Germany
| | - Florian Heinke
- Bioinformatics Group Mittweida, University of Applied Sciences Mittweida, Mittweida, Germany
| | - Sarah Hofmann
- Interdisziplinäres Ökologisches Zentrum, Technische Universität Bergakademie Freiberg, Freiberg, Germany
| | - Janosch A D Gröning
- Interdisziplinäres Ökologisches Zentrum, Technische Universität Bergakademie Freiberg, Freiberg, Germany
| | - Dirk Labudde
- Bioinformatics Group Mittweida, University of Applied Sciences Mittweida, Mittweida, Germany
| | - Willem J H van Berkel
- Laboratory of Biochemistry, Wageningen University and Research, Wageningen, Netherlands
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Nielsen TK, Rasmussen M, Demanèche S, Cecillon S, Vogel TM, Hansen LH. Evolution of Sphingomonad Gene Clusters Related to Pesticide Catabolism Revealed by Genome Sequence and Mobilomics of Sphingobium herbicidovorans MH. Genome Biol Evol 2018; 9:2477-2490. [PMID: 28961970 PMCID: PMC5737581 DOI: 10.1093/gbe/evx185] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/07/2017] [Indexed: 12/03/2022] Open
Abstract
Bacterial degraders of chlorophenoxy herbicides have been isolated from various ecosystems, including pristine environments. Among these degraders, the sphingomonads constitute a prominent group that displays versatile xenobiotic-degradation capabilities. Four separate sequencing strategies were required to provide the complete sequence of the complex and plastic genome of the canonical chlorophenoxy herbicide-degrading Sphingobium herbicidovorans MH. The genome has an intricate organization of the chlorophenoxy-herbicide catabolic genes sdpA, rdpA, and cadABCD that encode the (R)- and (S)-enantiomer-specific 2,4-dichlorophenoxypropionate dioxygenases and four subunits of a Rieske non-heme iron oxygenase involved in 2-methyl-chlorophenoxyacetic acid degradation, respectively. Several major genomic rearrangements are proposed to help understand the evolution and mobility of these important genes and their genetic context. Single-strain mobilomic sequence analysis uncovered plasmids and insertion sequence-associated circular intermediates in this environmentally important bacterium and enabled the description of evolutionary models for pesticide degradation in strain MH and related organisms. The mobilome presented a complex mosaic of mobile genetic elements including four plasmids and several circular intermediate DNA molecules of insertion-sequence elements and transposons that are central to the evolution of xenobiotics degradation. Furthermore, two individual chromosomally integrated prophages were shown to excise and form free circular DNA molecules. This approach holds great potential for improving the understanding of genome plasticity, evolution, and microbial ecology.
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Affiliation(s)
| | | | - Sandrine Demanèche
- Environmental Microbial Genomics, Laboratoire Ampère (CNRS UMR5005), École Centrale de Lyon, Université de Lyon, Ecully, France
| | - Sébastien Cecillon
- Environmental Microbial Genomics, Laboratoire Ampère (CNRS UMR5005), École Centrale de Lyon, Université de Lyon, Ecully, France
| | - Timothy M Vogel
- Environmental Microbial Genomics, Laboratoire Ampère (CNRS UMR5005), École Centrale de Lyon, Université de Lyon, Ecully, France
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Huang X, He J, Yan X, Hong Q, Chen K, He Q, Zhang L, Liu X, Chuang S, Li S, Jiang J. Microbial catabolism of chemical herbicides: Microbial resources, metabolic pathways and catabolic genes. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2017; 143:272-297. [PMID: 29183604 DOI: 10.1016/j.pestbp.2016.11.010] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Revised: 11/21/2016] [Accepted: 11/23/2016] [Indexed: 06/07/2023]
Abstract
Chemical herbicides are widely used to control weeds and are frequently detected as contaminants in the environment. Due to their toxicity, the environmental fate of herbicides is of great concern. Microbial catabolism is considered the major pathway for the dissipation of herbicides in the environment. In recent decades, there have been an increasing number of reports on the catabolism of various herbicides by microorganisms. This review presents an overview of the recent advances in the microbial catabolism of various herbicides, including phenoxyacetic acid, chlorinated benzoic acid, diphenyl ether, tetra-substituted benzene, sulfonamide, imidazolinone, aryloxyphenoxypropionate, phenylurea, dinitroaniline, s-triazine, chloroacetanilide, organophosphorus, thiocarbamate, trazinone, triketone, pyrimidinylthiobenzoate, benzonitrile, isoxazole and bipyridinium herbicides. This review highlights the microbial resources that are capable of catabolizing these herbicides and the mechanisms involved in the catabolism. Furthermore, the application of herbicide-degrading strains to clean up herbicide-contaminated sites and the construction of genetically modified herbicide-resistant crops are discussed.
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Affiliation(s)
- Xing Huang
- Department of Microbiology, Key Lab of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, 210095 Nanjing, People's Republic of China
| | - Jian He
- Department of Microbiology, Key Lab of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, 210095 Nanjing, People's Republic of China
| | - Xin Yan
- Department of Microbiology, Key Lab of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, 210095 Nanjing, People's Republic of China
| | - Qing Hong
- Department of Microbiology, Key Lab of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, 210095 Nanjing, People's Republic of China
| | - Kai Chen
- Department of Microbiology, Key Lab of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, 210095 Nanjing, People's Republic of China
| | - Qin He
- Department of Microbiology, Key Lab of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, 210095 Nanjing, People's Republic of China
| | - Long Zhang
- Department of Microbiology, Key Lab of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, 210095 Nanjing, People's Republic of China
| | - Xiaowei Liu
- Department of Microbiology, Key Lab of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, 210095 Nanjing, People's Republic of China
| | - Shaochuang Chuang
- Department of Microbiology, Key Lab of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, 210095 Nanjing, People's Republic of China
| | - Shunpeng Li
- Department of Microbiology, Key Lab of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, 210095 Nanjing, People's Republic of China
| | - Jiandong Jiang
- Department of Microbiology, Key Lab of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, 210095 Nanjing, People's Republic of China.
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8
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Riedel A, Heine T, Westphal AH, Conrad C, Rathsack P, van Berkel WJH, Tischler D. Catalytic and hydrodynamic properties of styrene monooxygenases from Rhodococcus opacus 1CP are modulated by cofactor binding. AMB Express 2015; 5:112. [PMID: 26054733 PMCID: PMC4460183 DOI: 10.1186/s13568-015-0112-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 04/15/2015] [Indexed: 12/13/2022] Open
Abstract
Styrene monooxygenases (SMOs) are flavoenzymes catalyzing the epoxidation of styrene into styrene oxide. SMOs are composed of a monooxygenase (StyA) and a reductase (StyB). The latter delivers reduced FAD to StyA on the expense of NADH. We identified Rhodococcus opacus 1CP as the first microorganism to possess three different StyA isoforms occurring in two systems StyA1/StyA2B and StyA/StyB, respectively. The hydrodynamic properties of StyA isozymes were found to be modulated by the binding of the (reduced) FAD cofactor. StyA1 and SyA2B mainly occur as dimers in their active forms while StyA is a monomer. StyA1 showed the highest epoxidation activity and excellent enantioselectivity in aromatic sulfoxidation. The hydrodynamic and biocatalytic properties of SMOs from strain 1CP are of relevance for investigation of possible industrial applications.
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Gan HM, Gan HY, Ahmad NH, Aziz NA, Hudson AO, Savka MA. Whole genome sequencing and analysis reveal insights into the genetic structure, diversity and evolutionary relatedness of luxI and luxR homologs in bacteria belonging to the Sphingomonadaceae family. Front Cell Infect Microbiol 2015; 4:188. [PMID: 25621282 PMCID: PMC4288048 DOI: 10.3389/fcimb.2014.00188] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 12/16/2014] [Indexed: 12/18/2022] Open
Abstract
Here we report the draft genomes and annotation of four N-acyl homoserine lactone (AHL)-producing members from the family Sphingomonadaceae. Comparative genomic analyses of 62 Sphingomonadaceae genomes were performed to gain insights into the distribution of the canonical luxI/R-type quorum sensing (QS) network within this family. Forty genomes contained at least one luxR homolog while the genome of Sphingobium yanoikuyae B1 contained seven Open Reading Frames (ORFs) that have significant homology to that of luxR. Thirty-three genomes contained at least one luxI homolog while the genomes of Sphingobium sp. SYK6, Sphingobium japonicum, and Sphingobium lactosutens contained four luxI. Using phylogenetic analysis, the sphingomonad LuxR homologs formed five distinct clades with two minor clades located near the plant associated bacteria (PAB) LuxR solo clade. This work for the first time shows that 13 Sphingobium and one Sphingomonas genome(s) contain three convergently oriented genes composed of two tandem luxR genes proximal to one luxI (luxR-luxR-luxI). Interestingly, luxI solos were identified in two Sphingobium species and may represent species that contribute to AHL-based QS system by contributing AHL molecules but are unable to perceive AHLs as signals. This work provides the most comprehensive description of the luxI/R circuitry and genome-based taxonomical description of the available sphingomonad genomes to date indicating that the presence of luxR solos and luxI solos are not an uncommon feature in members of the Sphingomonadaceae family.
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Affiliation(s)
- Han Ming Gan
- School of Science, Monash University Malaysia Petaling Jaya, Malaysia ; Genomics Facility, Monash University Malaysia Petaling Jaya, Malaysia
| | - Huan You Gan
- School of Science, Monash University Malaysia Petaling Jaya, Malaysia ; Genomics Facility, Monash University Malaysia Petaling Jaya, Malaysia
| | - Nurul H Ahmad
- Thomas H. Gosnell School of Life Sciences, Rochester Institute of Technology Rochester NY, USA
| | - Nazrin A Aziz
- Thomas H. Gosnell School of Life Sciences, Rochester Institute of Technology Rochester NY, USA
| | - André O Hudson
- Thomas H. Gosnell School of Life Sciences, Rochester Institute of Technology Rochester NY, USA
| | - Michael A Savka
- Thomas H. Gosnell School of Life Sciences, Rochester Institute of Technology Rochester NY, USA
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A mechanistic study on SMOB-ADP1: an NADH:flavin oxidoreductase of the two-component styrene monooxygenase of Acinetobacter baylyi ADP1. Arch Microbiol 2014; 196:829-45. [PMID: 25116410 DOI: 10.1007/s00203-014-1022-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Revised: 07/23/2014] [Accepted: 07/28/2014] [Indexed: 10/24/2022]
Abstract
Two styrene monooxygenase types, StyA/StyB and StyA1/StyA2B, have been described each consisting of an epoxidase and a reductase. A gene fusion which led to the chimeric reductase StyA2B and the occurrence in different phyla are major differences. Identification of SMOA/SMOB-ADP1 of Acinetobacter baylyi ADP1 may enlighten the gene fusion event since phylogenetic analysis indicated both proteins to be more related to StyA2B than to StyA/StyB. SMOB-ADP1 is classified like StyB and StyA2B as HpaC-like reductase. Substrate affinity and turnover number of the homo-dimer SMOB-ADP1 were determined for NADH (24 µM, 64 s(-1)) and FAD (4.4 µM, 56 s(-1)). SMOB-ADP1 catalysis follows a random sequential mechanism, and FAD fluorescence is quenched upon binding to SMOB-ADP1 (K d = 1.8 µM), which clearly distinguishes that reductase from StyB of Pseudomonas. In summary, this study confirmes made assumptions and provides phylogenetic and biochemical data for the differentiation of styrene monooxygenase-related flavin reductases.
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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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Khara P, Roy M, Chakraborty J, Ghosal D, Dutta TK. Functional characterization of diverse ring-hydroxylating oxygenases and induction of complex aromatic catabolic gene clusters in Sphingobium sp. PNB. FEBS Open Bio 2014; 4:290-300. [PMID: 24918041 PMCID: PMC4048848 DOI: 10.1016/j.fob.2014.03.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 03/03/2014] [Accepted: 03/03/2014] [Indexed: 11/27/2022] Open
Abstract
Sphingobium sp. PNB, like other sphingomonads, has multiple ring-hydroxylating oxygenase (RHO) genes. Three different fosmid clones have been sequenced to identify the putative genes responsible for the degradation of various aromatics in this bacterial strain. Comparison of the map of the catabolic genes with that of different sphingomonads revealed a similar arrangement of gene clusters that harbors seven sets of RHO terminal components and a sole set of electron transport (ET) proteins. The presence of distinctly conserved amino acid residues in ferredoxin and in silico molecular docking analyses of ferredoxin with the well characterized terminal oxygenase components indicated the structural uniqueness of the ET component in sphingomonads. The predicted substrate specificities, derived from the phylogenetic relationship of each of the RHOs, were examined based on transformation of putative substrates and their structural homologs by the recombinant strains expressing each of the oxygenases and the sole set of available ET proteins. The RHO AhdA1bA2b was functionally characterized for the first time and was found to be capable of transforming ethylbenzene, propylbenzene, cumene, p-cymene and biphenyl, in addition to a number of polycyclic aromatic hydrocarbons. Overexpression of aromatic catabolic genes in strain PNB, revealed by real-time PCR analyses, is a way forward to understand the complex regulation of degradative genes in sphingomonads.
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Affiliation(s)
| | | | | | | | - Tapan K. Dutta
- Department of Microbiology, Bose Institute, P-1/12 C.I.T. Scheme VII M, Kolkata 700054, India
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Nielsen TK, Xu Z, Gözdereliler E, Aamand J, Hansen LH, Sørensen SR. Novel insight into the genetic context of the cadAB genes from a 4-chloro-2-methylphenoxyacetic acid-degrading Sphingomonas. PLoS One 2013; 8:e83346. [PMID: 24391756 PMCID: PMC3877037 DOI: 10.1371/journal.pone.0083346] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Accepted: 11/01/2013] [Indexed: 11/19/2022] Open
Abstract
The 2-methyl-4-chlorophenoxyacetic (MCPA) acid-degrader Sphingomonas sp. ERG5 has recently been isolated from MCPA-degrading bacterial communities. Using Illumina-sequencing, the 5.7 Mb genome of this isolate was sequenced in this study, revealing the 138 kbp plasmid pCADAB1 harboring the 32.5 kbp composite transposon Tn6228 which contains genes encoding proteins for the removal of 2,4-dichlorophenoxyacetic acid (2,4-D) and MCPA, as well as the regulation of this pathway. Transposon Tn6228 was confirmed by PCR to be situated on the plasmid and also exist in a circular intermediate state - typical of IS3 elements. The canonical tfdAα-gene of group III 2,4-D degraders, encoding the first step in degradation of 2,4-D and related compounds, was not present in the chromosomal contigs. However, the alternative cadAB genes, also providing the initial degradation step, were found in Tn6228, along with the 2,4-D-degradation-associated genes tfdBCDEFKR and cadR. Putative reductase and ferredoxin genes cadCD of Rieske non-heme iron oxygenases were also present in close proximity to cadAB, suggesting that these might have an unknown role in the initial degradation reaction. Parts of the composite transposon contain sequence displaying high similarity to previously analyzed 2,4-D degradation genes, suggesting rapid dissemination and high conservation of the chlorinated-phenoxyacetic acid (PAA)-degradation genotype among the sphingomonads.
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Affiliation(s)
- Tue Kjærgaard Nielsen
- Department of Geochemistry, Geological Survey of Denmark and Greenland, Copenhagen, Denmark
- Section for Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Zhuofei Xu
- Section for Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Erkin Gözdereliler
- Department of Geochemistry, Geological Survey of Denmark and Greenland, Copenhagen, Denmark
| | - Jens Aamand
- Department of Geochemistry, Geological Survey of Denmark and Greenland, Copenhagen, Denmark
| | | | - Sebastian R. Sørensen
- Department of Geochemistry, Geological Survey of Denmark and Greenland, Copenhagen, Denmark
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A novel hydrolase identified by genomic-proteomic analysis of phenylurea herbicide mineralization by Variovorax sp. strain SRS16. Appl Environ Microbiol 2011; 77:8754-64. [PMID: 22003008 DOI: 10.1128/aem.06162-11] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The soil bacterial isolate Variovorax sp. strain SRS16 mineralizes the phenylurea herbicide linuron. The proposed pathway initiates with hydrolysis of linuron to 3,4-dichloroaniline (DCA) and N,O-dimethylhydroxylamine, followed by conversion of DCA to Krebs cycle intermediates. Differential proteomic analysis showed a linuron-dependent upregulation of several enzymes that fit into this pathway, including an amidase (LibA), a multicomponent chloroaniline dioxygenase, and enzymes associated with a modified chlorocatechol ortho-cleavage pathway. Purified LibA is a monomeric linuron hydrolase of ∼55 kDa with a K(m) and a V(max) for linuron of 5.8 μM and 0.16 nmol min⁻¹, respectively. This novel member of the amidase signature family is unrelated to phenylurea-hydrolyzing enzymes from Gram-positive bacteria and lacks activity toward other tested phenylurea herbicides. Orthologues of libA are present in all other tested linuron-degrading Variovorax strains with the exception of Variovorax strains WDL1 and PBS-H4, suggesting divergent evolution of the linuron catabolic pathway in different Variovorax strains. The organization of the linuron degradation genes identified in the draft SRS16 genome sequence indicates that gene patchwork assembly is at the origin of the pathway. Transcription analysis suggests that a catabolic intermediate, rather than linuron itself, acts as effector in activation of the pathway. Our study provides the first report on the genetic organization of a bacterial pathway for complete mineralization of a phenylurea herbicide and the first report on a linuron hydrolase in Gram-negative bacteria.
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Liang B, Jiang J, Zhang J, Zhao Y, Li S. Horizontal transfer of dehalogenase genes involved in the catalysis of chlorinated compounds: evidence and ecological role. Crit Rev Microbiol 2011; 38:95-110. [DOI: 10.3109/1040841x.2011.618114] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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16
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Patchwork assembly of nag-like nitroarene dioxygenase genes and the 3-chlorocatechol degradation cluster for evolution of the 2-chloronitrobenzene catabolism pathway in Pseudomonas stutzeri ZWLR2-1. Appl Environ Microbiol 2011; 77:4547-52. [PMID: 21602392 DOI: 10.1128/aem.02543-10] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas stutzeri ZWLR2-1 utilizes 2-chloronitrobenzene (2CNB) as a sole source of carbon, nitrogen, and energy. To identify genes involved in this pathway, a 16.2-kb DNA fragment containing putative 2CNB dioxygenase genes was cloned and sequenced. Of the products from the 19 open reading frames that resulted from this fragment, CnbAc and CnbAd exhibited striking identities to the respective α and β subunits of the Nag-like ring-hydroxylating dioxygenases involved in the metabolism of nitrotoluene, nitrobenzene, and naphthalene. The encoding genes were also flanked by two copies of insertion sequence IS6100. CnbAa and CnbAb are similar to the ferredoxin reductase and ferredoxin for anthranilate 1,2-dioxygenase from Burkholderia cepacia DBO1. Escherichia coli cells expressing cnbAaAbAcAd converted 2CNB to 3-chlorocatechol with concomitant nitrite release. Cell extracts of E. coli/pCNBC exhibited chlorocatechol 1,2-dioxygenase activity. The cnbCDEF gene cluster, homologous to a 3-chlorocatechol degradation cluster in Sphingomonas sp. strain TFD44, probably contains all of the genes necessary for the conversion of 3-chlorocatechol to 3-oxoadipate. The patchwork-like structure of this catabolic cluster suggests that the cnb cluster for 2CNB degradation evolved by recruiting two catabolic clusters encoding a nitroarene dioxygenase and a chlorocatechol degradation pathway. This provides another example to help elucidate the bacterial evolution of catabolic pathways in response to xenobiotic chemicals.
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Sipilä TP, Väisänen P, Paulin L, Yrjälä K. Sphingobium sp. HV3 degrades both herbicides and polyaromatic hydrocarbons using ortho- and meta-pathways with differential expression shown by RT-PCR. Biodegradation 2010; 21:771-84. [DOI: 10.1007/s10532-010-9342-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2009] [Accepted: 02/09/2010] [Indexed: 11/29/2022]
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18
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Identification of a novel self-sufficient styrene monooxygenase from Rhodococcus opacus 1CP. J Bacteriol 2009; 191:4996-5009. [PMID: 19482928 DOI: 10.1128/jb.00307-09] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Sequence analysis of a 9-kb genomic fragment of the actinobacterium Rhodococcus opacus 1CP led to identification of an open reading frame encoding a novel fusion protein, StyA2B, with a putative function in styrene metabolism via styrene oxide and phenylacetic acid. Gene cluster analysis indicated that the highly related fusion proteins of Nocardia farcinica IFM10152 and Arthrobacter aurescens TC1 are involved in a similar physiological process. Whereas 413 amino acids of the N terminus of StyA2B are highly similar to those of the oxygenases of two-component styrene monooxygenases (SMOs) from pseudomonads, the residual 160 amino acids of the C terminus show significant homology to the flavin reductases of these systems. Cloning and functional expression of His(10)-StyA2B revealed for the first time that the fusion protein does in fact catalyze two separate reactions. Strictly NADH-dependent reduction of flavins and highly enantioselective oxygenation of styrene to (S)-styrene oxide were shown. Inhibition studies and photometric analysis of recombinant StyA2B indicated the absence of tightly bound heme and flavin cofactors in this self-sufficient monooxygenase. StyA2B oxygenates a spectrum of aromatic compounds similar to those of two-component SMOs. However, the specific activities of the flavin-reducing and styrene-oxidizing functions of StyA2B are one to two orders of magnitude lower than those of StyA/StyB from Pseudomonas sp. strain VLB120.
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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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Molecular characteristics of xenobiotic-degrading sphingomonads. Appl Microbiol Biotechnol 2008; 81:793-811. [PMID: 19002456 DOI: 10.1007/s00253-008-1752-3] [Citation(s) in RCA: 150] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2008] [Revised: 10/06/2008] [Accepted: 10/15/2008] [Indexed: 10/21/2022]
Abstract
The genus Sphingomonas (sensu latu) belongs to the alpha-Proteobacteria and comprises strictly aerobic chemoheterotrophic bacteria that are widespread in various aquatic and terrestrial environments. The members of this genus are often isolated and studied because of their ability to degrade recalcitrant natural and anthropogenic compounds, such as (substituted) biphenyl(s) and naphthalene(s), fluorene, (substituted) phenanthrene(s), pyrene, (chlorinated) diphenylether(s), (chlorinated) furan(s), (chlorinated) dibenzo-p-dioxin(s), carbazole, estradiol, polyethylene glycols, chlorinated phenols, nonylphenols, and different herbicides and pesticides. The metabolic versatility of these organisms suggests that they have evolved mechanisms to adapt quicker and/or more efficiently to the degradation of novel compounds in the environment than members of other bacterial genera. Comparative analyses demonstrate that sphingomonads generally use similar degradative pathways as other groups of microorganisms but deviate from competing microorganisms by the existence of multiple hydroxylating oxygenases and the conservation of specific gene clusters. Furthermore, there is increasing evidence for the existence of plasmids that only can be disseminated among sphingomonads and which undergo after conjugative transfer pronounced rearrangements.
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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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Blasco R, Ramos JL, Wittich RM. Pseudomonas aeruginosa strain RW41 mineralizes 4-chlorobenzenesulfonate, the major polar by-product from DDT manufacturing. Environ Microbiol 2008; 10:1591-600. [DOI: 10.1111/j.1462-2920.2008.01575.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Manickam N, Misra R, Mayilraj S. A novel pathway for the biodegradation of gamma-hexachlorocyclohexane by a Xanthomonas sp. strain ICH12. J Appl Microbiol 2007; 102:1468-78. [PMID: 17578411 DOI: 10.1111/j.1365-2672.2006.03209.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIM To isolate gamma-hexachlorocyclohexane (HCH)-degrading bacteria from contaminated soil and characterize the metabolites formed and the genes involved in the degradation pathway. METHODS AND RESULTS A bacterial strain Xanthomonas sp. ICH12, capable of biodegrading gamma- HCH was isolated from HCH-contaminated soil. DNA-colony hybridization method was employed to detect bacterial populations containing specific gene sequences of the gamma-HCH degradation pathway. linA (dehydrodehalogenase), linB (hydrolytic dehalogenase) and linC (dehydrogenase) from a Sphingomonas paucimobilis UT26, reportedly possessing gamma-HCH degradation activity, were used as gene probes against isolated colonies. The isolate was found to grow and utilize gamma-HCH as the sole carbon and energy source. The 16S ribosomal RNA gene sequence of the isolate resulted in its identification as a Xanthomonas species, and we designated it as strain ICH12. During the degradation of gamma-HCH by ICH12, formation of two intermediates, gamma-2,3,4,5,6-pentachlorocyclohexene (gamma-PCCH), and 2,5-dichlorobenzoquinone (2,5-DCBQ), were identified by gas chromatography-mass spectrometric (GC-MS) analysis. While gamma-PCCH was reported previously, 2,5-dichlorohydroquinone was a novel metabolite from HCH degradation. CONCLUSIONS A Xanthomonas sp. for gamma-HCH degradation from a contaminated soil was isolated. gamma-HCH was utilized as sole source of carbon and energy, and the degradation proceeds by successive dechlorination. Two degradation products gamma-PCCH and 2,5-DCBQ were characterized, and the latter metabolite was not known in contrasts with the previous studies. The present work, for the first time, demonstrates the potential of a Xanthomonas species to degrade a recalcitrant and widespread pollutant like gamma-HCH. SIGNIFICANCE AND IMPACT OF THE STUDY This study demonstrates the isolation and characterization of a novel HCH-degrading bacterium. Further results provide an insight into the novel degradation pathway which may exist in diverse HCH-degrading bacteria in contaminated soils leading to bioremediation of gamma-HCH.
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Affiliation(s)
- N Manickam
- Environmental Biotechnology, Industrial Toxicology Research Centre, Lucknow, India.
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Balcke GU, Wegener S, Kiesel B, Benndorf D, Schlömann M, Vogt C. Kinetics of chlorobenzene biodegradation under reduced oxygen levels. Biodegradation 2007; 19:507-18. [DOI: 10.1007/s10532-007-9156-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2007] [Accepted: 10/01/2007] [Indexed: 11/30/2022]
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Sakai Y, Ogawa N, Fujii T, Sugahara K, Miyashita K, Hasebe A. 2,4-Dichrolophenoxyacetic Acid-degrading Genes from Bacteria Isolated from Soil in Japan: Spread of Burkholderia cepacia RASC-type Degrading Genes Harbored on Large Plasmids. Microbes Environ 2007. [DOI: 10.1264/jsme2.22.145] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Yoriko Sakai
- National Institute for Agro-Environmental Sciences
| | - Naoto Ogawa
- National Institute for Agro-Environmental Sciences
| | | | | | | | - Akira Hasebe
- National Institute for Agro-Environmental Sciences
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Popp N, Schlömann M, Mau M. Bacterial diversity in the active stage of a bioremediation system for mineral oil hydrocarbon-contaminated soils. Microbiology (Reading) 2006; 152:3291-3304. [PMID: 17074900 DOI: 10.1099/mic.0.29054-0] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Soils contaminated with mineral oil hydrocarbons are often cleaned in off-site bioremediation systems. In order to find out which bacteria are active during the degradation phase in such systems, the diversity of the active microflora in a degrading soil remediation system was investigated by small-subunit (SSU) rRNA analysis. Two sequential RNA extracts from one soil sample were generated by a procedure incorporating bead beating. Both extracts were analysed separately by generating individual SSU rDNA clone libraries from cDNA of the two extracts. The sequencing results showed moderate diversity. The two clone libraries were dominated by Gammaproteobacteria, especially Pseudomonas spp. Alphaproteobacteria and Betaproteobacteria were two other large groups in the clone libraries. Actinobacteria, Firmicutes, Bacteroidetes and Epsilonproteobacteria were detected in lower numbers. The obtained sequences were predominantly related to genera for which cultivated representatives have been described, but were often clustered together in the phylogenetic tree, and the sequences that were most similar were originally obtained from soils and not from pure cultures. Most of the dominant genera in the clone libraries, e.g. Pseudomonas, Acinetobacter, Sphingomonas, Acidovorax and Thiobacillus, had already been detected in (mineral oil hydrocarbon) contaminated environmental samples. The occurrence of the genera Zymomonas and Rhodoferax was novel in mineral oil hydrocarbon-contaminated soil.
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Affiliation(s)
- Nicole Popp
- Interdisziplinäres Ökologisches Zentrum, TU Bergakademie Freiberg, Leipziger Str. 29, D-09599 Freiberg, Germany
| | - Michael Schlömann
- Interdisziplinäres Ökologisches Zentrum, TU Bergakademie Freiberg, Leipziger Str. 29, D-09599 Freiberg, Germany
| | - Margit Mau
- Interdisziplinäres Ökologisches Zentrum, TU Bergakademie Freiberg, Leipziger Str. 29, D-09599 Freiberg, Germany
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Lal R, Dogra C, Malhotra S, Sharma P, Pal R. Diversity, distribution and divergence of lin genes in hexachlorocyclohexane-degrading sphingomonads. Trends Biotechnol 2006; 24:121-30. [PMID: 16473421 DOI: 10.1016/j.tibtech.2006.01.005] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2005] [Revised: 10/24/2005] [Accepted: 01/13/2006] [Indexed: 10/25/2022]
Abstract
Two forms of hexachlorocyclohexane (HCH), gamma-HCH (lindane) and technical HCH (incorporating alpha-, beta-, gamma- and delta- isomers), have been used against agricultural pests and in health programs since the 1940s. Although all the isomers are present in the milieu, delta- and beta-HCH isomers are the most problematic and present a serious environmental problem. Bacteria that degrade HCH isomers have been isolated from HCH contaminated soils from different geographical locations around the world (from the family Sphingomonadaceae). Interestingly, all these bacteria contain nearly identical lin genes (responsible for HCH degradation), which are diverging to perform several catabolic functions. The organization and diversity of lin genes have been studied among several sphingomonads, and they have been found to be associated with plasmids and IS6100, both of which appear to have a significant role in their horizontal transfer. The knowledge of the molecular genetics, diversity and distribution of lin genes, and the potential of sphingomonads to degrade HCH isomers, can now be used for developing bioremediation techniques for the decontamination of HCH contaminated sites.
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Affiliation(s)
- Rup Lal
- Department of Zoology, University of Delhi, Delhi-110 007, India.
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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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