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==Classification==
==Classification==


[[Image:anaerobe.jpg|frame|right|Anaeromyxobacter dehalogenans is a Gram-negative rod-shaped, motile, spore-forming bacteria found in the soil.]]
[[Image:anaerobe.jpg|frame|right|Anaeromyxobacter dehalogenans is a Gram-negative rod-shaped, motile, spore-forming bacteria found in the soil. Image courtesy of the Joint Genome Institute.
http://gib.genes.nig.ac.jp/
Fumoto et al, Nucleic Acids Res. 30: 66-68 (2002) http://genome.jgi-psf.org/draft_microbes/images/anade.jpg.]]


===Higher order taxa===
===Higher order taxa===


Bacteria; Proteobacteria; delta/epsilon subdivisions; Deltaproteobacteria; Myxococcales; Cystobacterineae; Myxococcaceae; Anaeromyxobacter.
 
Bacteria; Proteobacteria; delta/epsilon subdivisions; Deltaproteobacteria; Myxococcales; Cystobacterineae; Myxococcaceae; ''Anaeromyxobacter''.


===Species===
===Species===
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The "Anaeromyxobacter dehalogenans" 2CP-C strain has been most studied and its complete genomic sequence has been determined. Species that fall under Anaeromyxobacter dehalogenans are ''Anaeromyxobacter sp. FAc12, Anaeromyxobacter sp. Fw109-5'' and environmental samples such as uncultured ''Anaeromyxobacter sp.''
 
The ''Anaeromyxobacter dehalogenans'' 2CP-C strain has been most studied and its complete genomic sequence has been determined. Species that fall under Anaeromyxobacter dehalogenans are ''Anaeromyxobacter sp. FAc12, Anaeromyxobacter sp. Fw109-5'' and environmental samples such as uncultured ''Anaeromyxobacter sp.''


==Description and significance==
==Description and significance==
[[Image:Adbacteria.jpg‎|right|300px|Anaeromyxobacter dehalogenans strain 2CP-C is a good model for studying the interaction of respiring chlorinated organic compounds and metals.]]
''Anaeromyxobacter dehalogenans'' is a slender Gram-negative rod-shaped spore-forming soil bacterium. It is capable of a gliding motility and forms a spore-like structure (Char/Desc). It was the first ''Myxobacterium'' that was found capable of anaerobic respiration, wherein it is able to grow by coupling the oxidation of both acetate or hydrogen, which is a distinguishing property of the organism from other reducing populations, to the reduction of ortho-substituted halophenols, ferric iron, nitrate, nitrite and fumarate (2). It was first isolated by enrichment and isolation of single plate-grown colonies obtained from uranium-contaminated sediment collected at the U.S. DOE Field Research Center near Oak Ridge, TN, which allowed for a 16s rRNA gene-based community analysis of the sample that suggested that the species helped in metal reduction (3). These metal-reducing microorganisms are widely distributed in the environment (2). It has been found in undisturbed and contaminated soils and sediments, and evidence shows they also exist in acidic subsurface sediments (4).


''A. dehalogenans'' is an important model organism that exists as both as a productive dechlorinator and metal reducer. Sequencing this bacteria also provides information about the reductive dehalogenase genes and the organization of its operon, which will help to design nucleic acid-based tools to "detect, monitor and quantify functional genes involved in reductive dechlorination processes at contaminated sites" (5). By studying the potential interferences between the competing substrates in contaminated environments we can further understand bioremediation efforts (2).
 
 
''Anaeromyxobacter dehalogenans'' is a slender Gram-negative rod-shaped spore-forming soil bacterium. It is capable of a gliding motility and it forms a spore-like structure (1). It was the first ''Myxobacterium'' that was found capable of anaerobic respiration, wherein it is able to grow by coupling the oxidation of both acetate or hydrogen, which is a distinguishing property of the organism from other reducing populations, to the reduction of ortho-substituted halophenols, ferric iron, nitrate, nitrite, nitrous oxide, manganese oxide, uranium (VI) and fumarate (1).  Of interest is its unique respiratory reduction of nitrate and nitrite to ammonia which is not linked to its ability to reduce nitrous oxide to nitrogen gas.
 
 
The first culture (strain 2CP-1) was first isolated by anaerobic enrichment from a Michigan soil sample on 2-chlorophenol and acetate followed by growth of single plate-grown colonies.  Subsequent isolates  were obtained from tropical rainforest soil and a Michigan compost (strains 2CP-3 and 2CP-C).  Once it was recognized that Anaeromyxobacter strains could reduce metals,  evidence was obtained of their presence soil uranium-contaminated sediment collected at the U.S. DOE Field Research Center near Oak Ridge, TN.  This evidence based on 16s rRNA gene-based community analysis of the sample suggested that the species helped in metal reduction (3).  This led to the isolation of several new Anaeromyxobacter stains (FW-109, FRCW, FRCR-5 and FRCD-1) from this uranium impacted site.  These metal-reducing microorganisms are widely distributed in the environment (1). Anaeromyxobacter strains have been found in undisturbed and contaminated soils and sediments, and evidence shows they also exist in acidic subsurface sediments (3) and agricultural soils (strains R, DCP-15, DCP-19, DCP-18 and DCP-2).
 
 
''A. dehalogenans'' is an important model organism that exists as both as a productive dechlorinator and metal reducer. Sequencing the genome of this bacteria (strains 2CP-C, 2CP-1, K and FW-109 by DOE Joint Genome Institute (JGI)) also provides information about the reductive dehalogenase genes, metal reduction biochemistry and the organization of its operon.  This will help in the design of nucleic acid-based tools to "detect, monitor and quantify functional genes involved in reductive dechlorination processes at contaminated sites" (4). By studying the potential interferences between the competing substrates in contaminated environments we can further understand bioremediation efforts (1).


==Genome structure==
==Genome structure==


[[Image:Adeh_2CPC_.jpg|right|300px|The anaeromyxobacter dehalogenans genome size is 5,013,479 base pairs.]]
[[Image:AdGenome.jpg‎|frame|right|300px|The anaeromyxobacter dehalogenans genome size is 5,013,479 base pairs. Image courtesy of the Joint Genome Institute
http://gib.genes.nig.ac.jp/
Fumoto et al, Nucleic Acids Res. 30: 66-68 (2002) http://gib.genes.nig.ac.jp/single/index.php?spid=Adeh_2CPC]]


The Joint Genome Institute has determined the complete genomic sequence of ''A. dehalogenans'' strain 2CP-C. Its replicon type is the chromosome. The genome of contains 5,013,479 bp, 4,346 genes and its predicted origin is at 3,425 kbp. It contains 58 RNA genes. It has a 75% GC content and a 25 % AT content. It is found as 90% coding. Its molecule is DNA.


''A. dehalogenans'' has a circular chromosome topography. It does not have any plasmids.
The Joint Genome Institute has determined the complete genomic sequence of ''A. dehalogenans'' strain 2CP-C.  The genome of contains 5,013,479 bp, 4,346 genes and its predicted origin is at 3,425 kbp. It contains 58 RNA genes. It has a 75% GC content and a 25 % AT content. It is found as 90% coding.  ''A. dehalogenans'' has a circular chromosome topography. It does not have any plasmids.


==Cell structure and metabolism==
==Cell structure and metabolism==


Anaeromyxobacter dehalogenans has anaerobic growth and lacks a fruiting body, which is uncharactaristic of the Myxococcus subgroup it belongs to, but it can be considered a Myxococcus due to other close resemblences (2). It is a member of the delta-proteobacteria group that exhibits anaerobic diversity like sulfate reduction, iron reduction, fermentation and dehalogenation (32 Char/Desc). The A. dehalogenan lifestyle allows halogenated compounds to be used as electron acceptors for growth (13 Char/Desc) and chlororespiration enables the organism to release energy for growth (10 Char/Desc).
''Anaeromyxobacter dehalogenans'' exhibits both aerobic and anaerobic growth, preferring the latter.  It lacks a fruiting body, which is uncharactaristic of the ''Myxococcus'' subgroup it belongs to, but it can be considered a ''Myxococcus'' due to other similarities, both structural and genomic (1). As a member of the delta-proteobacteria group, however, anaerobic metabolism is not unusual (see Geobacter, Desulfovibrio or Desulfomonile). One ''A. dehalogenan'' metabolism type allows halogenated phenolic compounds to be used as electron acceptors for growth (7).  This "chlororespiration" (or halorespiration) takes advantage of the energy released during reductive dechlorination of compounds like 2-chlorophenol.  This energy is used by  the organism for growth (8).


A. dehalogenans has a great deal of metabolic diversity, such as "halorespiration of herbicides, ferric-ion reduction, ammoniafication, and N2O reduction" (6). It is able to grow under different redox conditions. It also has electron donor versatility and it uses oxidized metals like Uranium(VI) and Fe(III), phenols, oxygen, nitrite, nitrate and fumarate as terminal electron aceeptors (2). It is able to couple electron acceptor reduction with the oxidation of compounds such as formate, hydrogen, acetate, succinate, pyruvate and glucose (7).
''A. dehalogenans'' strains exhibit a great deal of metabolic diversity, such as halorespiration of herbicides, ferric-ion reduction, nitrate or nitrate reduction to ammonia, and N2O reduction to dinitrogen gas (5). It is able to grow under both oxic and anoxic redox conditions. It uses (oxidizes) a variety of electron donors, such as pyruvate, glucose, succinate, formate, acetate and`hydrogen (6). The oxidation of these donors is coupled to the use (reduction) of many types of respiratory electron acceptors (aerobic bacteria use oxygen as a terminal electron acceptor), such as Uranium(VI), Fe(III), Mn(IV), halophenols, oxygen, nitrite (to ammonia), nitrate (to ammonia), nitrous oxide (to dinitrogen) and fumarate  (1).


==Ecology==
==Ecology==


Anaerobic conditions have been found to possibly impact agrochemical fate, nutrient cycling, and plant/seed-microbe interactions and research has shown that A. dehalogenans are useful in charactarizing anaerobic agricultural soil processes in an observatory (6). Under environmentally relevant conditions this organism is robust and competitive as it acts as both a productive dechlorinator and a metal reducer. It is not affected by changing redox conditions and it is found to be active at a pH of 6-8.5 (2).
Anaerobic conditions have been found to possibly impact "agrochemical fate, nutrient cycling, and plant/seed-microbe interactions" and research has shown that ''A. dehalogenans'' is useful in "charactarizing anaerobic agricultural soil processes in an observatory" (5). Under environmentally relevant conditions this organism flourishes and is competitive as it acts as both a productive dechlorinator and a metal reducer. It is not affected by changing redox conditions and it is found to be active at a pH of 6-8.5 (1).


==Pathology==
==Pathology==


Anaeromyxobacter dehalogenans is not a pathogen, nor does it cause disease.
''Anaeromyxobacter dehalogenans'' is not a pathogen, nor does it cause disease.


==Application to Biotechnology==
==Application to Biotechnology==


Understanding the unique class of enzymes with novel catalytic proteins and the mechanisms involved in metal reduction can lead to biotechnological applications especially at sites that contain halogenated and chlorinated compounds, where biostimulation can occur by "supplying the populations of interest with reducing equivalents needed to reduce the contaminants"(5).
Understanding the class of enzymes involved in this organism's processes, the novel catalytic proteins and the mechanisms involved in metal reduction can lead to biotechnological applications especially at sites that contain halogenated and chlorinated compounds, where bioremediation is possible by "supplying the populations of interest with reducing equivalents needed to reduce the contaminants" (4).


==Current Research==
==Current Research==


1. Towards a More Complete Picture: Dissimillatory Metal Reduction by Anaeromyxobacter Species is a 3-year project lead by Frank Loeffler and Robert Sanford focusing on uranium reduction in the species. The research will look at the isolates of the bacteria and look at its physiological requirements. Molecular biology tools will be designed in order to detect and quantify samples in culture and in the environment with hopes to discover Anaeromyxobacter's distribution and abundance within the environment. Also, at in the Field Research Center they will attempt to isolate additional species.
1. Towards a More Complete Picture: Dissimillatory Metal Reduction by ''Anaeromyxobacter'' Species is a 3-year project lead by Frank Loeffler and Robert Sanford focusing on uranium reduction in the species. The research will look at the isolates of the bacteria and look at its physiological requirements. Molecular biology tools will be designed in order to detect and quantify samples in culture and in the environment with hopes to discover ''Anaeromyxobacter's'' distribution and abundance. Also, at the Field Research Center they will attempt to isolate additional species.


2. Biomolecular Mechanisms Controlling Metal and Radionuclide Transformations in Anaeromyoxybacter dehalogenans is a research project whose goal is to find out the "molecular mechanisms of radionuclide biotransformation" and "assess the effects of relevant environmental factors on these transformation reactions" (GEO). By using targeted physiological and genetic analysis and a microarray-based comparitive genomics approach they aim to find out the mechanisms involved allowing us to become more capable of predicting processes involved transformation in subsurface environments in order to use for bioremidiation.
2. Biomolecular Mechanisms Controlling Metal and Radionuclide Transformations in ''Anaeromyoxybacter dehalogenans'' is a research project whose goal is to find out the "molecular mechanisms of radionuclide biotransformation" and "assess the effects of relevant environmental factors on these transformation reactions" (9). By using targeted physiological and genetic analysis and a microarray-based comparitive genomics approach they aim to find out the mechanisms involved allowing us to become more capable of predicting processes involved transformation of subsurface environments in order to use for bioremediation.


3. Fast Dechlorination of Chlorinated Phenols by Anaeromyxobacter dehalogenans Strain 2CP-C is a research study by R. A. Sanford and Q. He at the University of Illinois which focuses on the physiology and kinetics of the dechlorination that allows the organism to grow. Using halogenated phenolic compounds they determine its rates of growth and dechlorination, and furthermore aim to determine if the strain can be used for the bioremediation of chlorinated phenols.
3. Fast Dechlorination of Chlorinated Phenols by ''Anaeromyxobacter dehalogenans'' Strain 2CP-C is a research study by R. A. Sanford and Q. He at the University of Illinois, focusing on the physiology and kinetics of the dechlorination that allows the organism to grow. Using halogenated phenolic compounds they determine rates of growth and dechlorination, and furthermore aim to determine if the strain can be used for the bioremediation of chlorinated phenols.


==References==
==References==


1. [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11823233&dopt=Abstract Sanford, R. A., J. R. Cole, and J. M. Tiedje. 2002. Characterization and description of Anaeromyxobacter dehalogenans gen. nov., sp. nov., an aryl halorespiring facultative anaerobic myxobacterium. Appl. Environ. Microbiol. 68:893-900.]


2. [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11823233&dopt=Abstract Sanford, R. A., J. R. Cole, and J. M. Tiedje. 2002. Characterization and description of Anaeromyxobacter dehalogenans gen. nov., sp. nov., an aryl halorespiring facultative anaerobic myxobacterium. Appl. Environ. Microbiol. 68:893-900.]
2. [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Search&db=pubmed&term=enumeration+and+characterization+of+iron+%28III%29+reducing+microbial+communities+from+acidic+subsurface&tool=fuzzy&ot=Enumeration+and+characterization+of+iron%28III%29%2Dreducing+microbial+communities+from+acidic+subsurface Petrie, L., N. N. North, S. L. Dollhopf, D. L. Balkwill, and L. E. Kostka. 2003. Enumeration and characterization of iron(III)-reducing microbial communities from acidic subsurface sediments contaminated with uranium. Appl. Environ. Microbiol. 69:7467-7479.]
 
3. [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Search&db=pubmed&term=enumeration+and+characterization+of+iron+%28III%29+reducing+microbial+communities+from+acidic+subsurface&tool=fuzzy&ot=Enumeration+and+characterization+of+iron%28III%29%2Dreducing+microbial+communities+from+acidic+subsurface Petrie, L., N. N. North, S. L. Dollhopf, D. L. Balkwill, and L. E. Kostka. 2003. Enumeration and characterization of iron(III)-reducing microbial communities from acidic subsurface sediments contaminated with uranium. Appl. Environ. Microbiol. 69:7467-7479.]


4.  
3.  
[http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=15294831&query_hl=11&itool=pubmed_docsum North, N. N., S. L. Dollhopf, L. Petrie, J. D. Istok, D. L. Balkwill, and J. E. Kostka. 2004. Change in bacterial community structure during in situ biostimulation of subsurface sediment cocontaminated with uranium and nitrate. Appl. Environ. Microbiol. 70:4911-4920.]
[http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=15294831&query_hl=11&itool=pubmed_docsum North, N. N., S. L. Dollhopf, L. Petrie, J. D. Istok, D. L. Balkwill, and J. E. Kostka. 2004. Change in bacterial community structure during in situ biostimulation of subsurface sediment cocontaminated with uranium and nitrate. Appl. Environ. Microbiol. 70:4911-4920.]
   
   
5. [http://genome.jgi-psf.org/finished_microbes/anade/anade.home.html Anaeromyxobacter dehalogenans 2CP-C IMG/Organism Details. Joint Genome Institute. 4 Jun 2007.]
4. [http://genome.jgi-psf.org/finished_microbes/anade/anade.home.html Anaeromyxobacter dehalogenans 2CP-C IMG/Organism Details. Joint Genome Institute. 4 Jun 2007.]
 
5. [http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=197244&pf=1 Chee Sanford, J.C., Sanford, R.A., Loffler, F.E., Thomas, S.H., Sims, G.K. 2006. Investigating anaerobic microbial processes in agricultural soils using Anaeromyxobacter dehalogenans as a cosmopolitan model.International Society for Microbial Ecology. 11:2025.]
 
6. [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Search&db=pubmed&term=characterization+of+fe+%28III%29+reduction+by+chlororespiring+anaeromyxobacter&tool=fuzzy&ot=Characterization+of+Fe%28III%29+Reduction+by+Chlororespiring+Anaeromxyobacter He, Q., and R. A. Sanford. 2003. Characterization of Fe(III) Reduction by Chlororespiring Anaeromxyobacter dehalogenans. Appl Environ Microbiol 69:2712-8.]
 
7. [http://pubs3.acs.org/acs/journals/doilookup?in_doi=10.1021/np50088a001 Gribble, G. W. 1992. Naturally occurring organohalogen compounds--a survey. J. Nat. Prod. 55:1353-1395.]


6. [http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=197244&pf=1 Chee Sanford, J.C., Sanford, R.A., Loffler, F.E., Thomas, S.H., Sims, G.K. 2006. Investigating anaerobic microbial processes in agricultural soils using Anaeromyxobacter dehalogenans as a cosmopolitan model.International Society for Microbial Ecology. 11:2025.]  
8. [http://pubs3.acs.org/acs/journals/doilookup?in_doi=10.1021/es00035a021 Dolfing, J., and B. K. Harrison. 1992. Gibbs free energy of formation of halogenated aromatic compounds and their potential role as electron acceptors in anaerobic environments. Environ. Sci. Technol. 26:2213-2218.]


7. [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Search&db=pubmed&term=characterization+of+fe+%28III%29+reduction+by+chlororespiring+anaeromyxobacter&tool=fuzzy&ot=Characterization+of+Fe%28III%29+Reduction+by+Chlororespiring+Anaeromxyobacter He, Q., and R. A. Sanford. 2003. Characterization of Fe(III) Reduction by Chlororespiring Anaeromxyobacter dehalogenans. Appl Environ Microbiol 69:2712-8.]
9. [http://www.lbl.gov/NABIRarchive/researchprogram/awards/biomolec_projects05.html Beliaev, Alex. 2005. Biomolecular Mechanisms Controlling Metal and Radionuclide Transformations in Anaeromyxobacter dehalogenans. Biomolecular Science and Engineering.]


Edited by student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano
Edited by Lori Joy Nacario, student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano

Latest revision as of 19:08, 8 June 2012

This is a curated page. Report corrections to Microbewiki.

A Microbial Biorealm page on the genus Anaeromyxobacter dehalogenans

Classification

Anaeromyxobacter dehalogenans is a Gram-negative rod-shaped, motile, spore-forming bacteria found in the soil. Image courtesy of the Joint Genome Institute. http://gib.genes.nig.ac.jp/ Fumoto et al, Nucleic Acids Res. 30: 66-68 (2002) http://genome.jgi-psf.org/draft_microbes/images/anade.jpg.

Higher order taxa

Bacteria; Proteobacteria; delta/epsilon subdivisions; Deltaproteobacteria; Myxococcales; Cystobacterineae; Myxococcaceae; Anaeromyxobacter.

Species

NCBI: Taxonomy


The Anaeromyxobacter dehalogenans 2CP-C strain has been most studied and its complete genomic sequence has been determined. Species that fall under Anaeromyxobacter dehalogenans are Anaeromyxobacter sp. FAc12, Anaeromyxobacter sp. Fw109-5 and environmental samples such as uncultured Anaeromyxobacter sp.

Description and significance

Anaeromyxobacter dehalogenans is a slender Gram-negative rod-shaped spore-forming soil bacterium. It is capable of a gliding motility and it forms a spore-like structure (1). It was the first Myxobacterium that was found capable of anaerobic respiration, wherein it is able to grow by coupling the oxidation of both acetate or hydrogen, which is a distinguishing property of the organism from other reducing populations, to the reduction of ortho-substituted halophenols, ferric iron, nitrate, nitrite, nitrous oxide, manganese oxide, uranium (VI) and fumarate (1). Of interest is its unique respiratory reduction of nitrate and nitrite to ammonia which is not linked to its ability to reduce nitrous oxide to nitrogen gas.


The first culture (strain 2CP-1) was first isolated by anaerobic enrichment from a Michigan soil sample on 2-chlorophenol and acetate followed by growth of single plate-grown colonies. Subsequent isolates were obtained from tropical rainforest soil and a Michigan compost (strains 2CP-3 and 2CP-C). Once it was recognized that Anaeromyxobacter strains could reduce metals, evidence was obtained of their presence soil uranium-contaminated sediment collected at the U.S. DOE Field Research Center near Oak Ridge, TN. This evidence based on 16s rRNA gene-based community analysis of the sample suggested that the species helped in metal reduction (3). This led to the isolation of several new Anaeromyxobacter stains (FW-109, FRCW, FRCR-5 and FRCD-1) from this uranium impacted site. These metal-reducing microorganisms are widely distributed in the environment (1). Anaeromyxobacter strains have been found in undisturbed and contaminated soils and sediments, and evidence shows they also exist in acidic subsurface sediments (3) and agricultural soils (strains R, DCP-15, DCP-19, DCP-18 and DCP-2).


A. dehalogenans is an important model organism that exists as both as a productive dechlorinator and metal reducer. Sequencing the genome of this bacteria (strains 2CP-C, 2CP-1, K and FW-109 by DOE Joint Genome Institute (JGI)) also provides information about the reductive dehalogenase genes, metal reduction biochemistry and the organization of its operon. This will help in the design of nucleic acid-based tools to "detect, monitor and quantify functional genes involved in reductive dechlorination processes at contaminated sites" (4). By studying the potential interferences between the competing substrates in contaminated environments we can further understand bioremediation efforts (1).

Genome structure

The anaeromyxobacter dehalogenans genome size is 5,013,479 base pairs. Image courtesy of the Joint Genome Institute http://gib.genes.nig.ac.jp/ Fumoto et al, Nucleic Acids Res. 30: 66-68 (2002) http://gib.genes.nig.ac.jp/single/index.php?spid=Adeh_2CPC


The Joint Genome Institute has determined the complete genomic sequence of A. dehalogenans strain 2CP-C. The genome of contains 5,013,479 bp, 4,346 genes and its predicted origin is at 3,425 kbp. It contains 58 RNA genes. It has a 75% GC content and a 25 % AT content. It is found as 90% coding. A. dehalogenans has a circular chromosome topography. It does not have any plasmids.

Cell structure and metabolism

Anaeromyxobacter dehalogenans exhibits both aerobic and anaerobic growth, preferring the latter. It lacks a fruiting body, which is uncharactaristic of the Myxococcus subgroup it belongs to, but it can be considered a Myxococcus due to other similarities, both structural and genomic (1). As a member of the delta-proteobacteria group, however, anaerobic metabolism is not unusual (see Geobacter, Desulfovibrio or Desulfomonile). One A. dehalogenan metabolism type allows halogenated phenolic compounds to be used as electron acceptors for growth (7). This "chlororespiration" (or halorespiration) takes advantage of the energy released during reductive dechlorination of compounds like 2-chlorophenol. This energy is used by the organism for growth (8).

A. dehalogenans strains exhibit a great deal of metabolic diversity, such as halorespiration of herbicides, ferric-ion reduction, nitrate or nitrate reduction to ammonia, and N2O reduction to dinitrogen gas (5). It is able to grow under both oxic and anoxic redox conditions. It uses (oxidizes) a variety of electron donors, such as pyruvate, glucose, succinate, formate, acetate and`hydrogen (6). The oxidation of these donors is coupled to the use (reduction) of many types of respiratory electron acceptors (aerobic bacteria use oxygen as a terminal electron acceptor), such as Uranium(VI), Fe(III), Mn(IV), halophenols, oxygen, nitrite (to ammonia), nitrate (to ammonia), nitrous oxide (to dinitrogen) and fumarate (1).

Ecology

Anaerobic conditions have been found to possibly impact "agrochemical fate, nutrient cycling, and plant/seed-microbe interactions" and research has shown that A. dehalogenans is useful in "charactarizing anaerobic agricultural soil processes in an observatory" (5). Under environmentally relevant conditions this organism flourishes and is competitive as it acts as both a productive dechlorinator and a metal reducer. It is not affected by changing redox conditions and it is found to be active at a pH of 6-8.5 (1).

Pathology

Anaeromyxobacter dehalogenans is not a pathogen, nor does it cause disease.

Application to Biotechnology

Understanding the class of enzymes involved in this organism's processes, the novel catalytic proteins and the mechanisms involved in metal reduction can lead to biotechnological applications especially at sites that contain halogenated and chlorinated compounds, where bioremediation is possible by "supplying the populations of interest with reducing equivalents needed to reduce the contaminants" (4).

Current Research

1. Towards a More Complete Picture: Dissimillatory Metal Reduction by Anaeromyxobacter Species is a 3-year project lead by Frank Loeffler and Robert Sanford focusing on uranium reduction in the species. The research will look at the isolates of the bacteria and look at its physiological requirements. Molecular biology tools will be designed in order to detect and quantify samples in culture and in the environment with hopes to discover Anaeromyxobacter's distribution and abundance. Also, at the Field Research Center they will attempt to isolate additional species.

2. Biomolecular Mechanisms Controlling Metal and Radionuclide Transformations in Anaeromyoxybacter dehalogenans is a research project whose goal is to find out the "molecular mechanisms of radionuclide biotransformation" and "assess the effects of relevant environmental factors on these transformation reactions" (9). By using targeted physiological and genetic analysis and a microarray-based comparitive genomics approach they aim to find out the mechanisms involved allowing us to become more capable of predicting processes involved transformation of subsurface environments in order to use for bioremediation.

3. Fast Dechlorination of Chlorinated Phenols by Anaeromyxobacter dehalogenans Strain 2CP-C is a research study by R. A. Sanford and Q. He at the University of Illinois, focusing on the physiology and kinetics of the dechlorination that allows the organism to grow. Using halogenated phenolic compounds they determine rates of growth and dechlorination, and furthermore aim to determine if the strain can be used for the bioremediation of chlorinated phenols.

References

1. Sanford, R. A., J. R. Cole, and J. M. Tiedje. 2002. Characterization and description of Anaeromyxobacter dehalogenans gen. nov., sp. nov., an aryl halorespiring facultative anaerobic myxobacterium. Appl. Environ. Microbiol. 68:893-900.

2. Petrie, L., N. N. North, S. L. Dollhopf, D. L. Balkwill, and L. E. Kostka. 2003. Enumeration and characterization of iron(III)-reducing microbial communities from acidic subsurface sediments contaminated with uranium. Appl. Environ. Microbiol. 69:7467-7479.

3. North, N. N., S. L. Dollhopf, L. Petrie, J. D. Istok, D. L. Balkwill, and J. E. Kostka. 2004. Change in bacterial community structure during in situ biostimulation of subsurface sediment cocontaminated with uranium and nitrate. Appl. Environ. Microbiol. 70:4911-4920.

4. Anaeromyxobacter dehalogenans 2CP-C IMG/Organism Details. Joint Genome Institute. 4 Jun 2007.

5. Chee Sanford, J.C., Sanford, R.A., Loffler, F.E., Thomas, S.H., Sims, G.K. 2006. Investigating anaerobic microbial processes in agricultural soils using Anaeromyxobacter dehalogenans as a cosmopolitan model.International Society for Microbial Ecology. 11:2025.

6. He, Q., and R. A. Sanford. 2003. Characterization of Fe(III) Reduction by Chlororespiring Anaeromxyobacter dehalogenans. Appl Environ Microbiol 69:2712-8.

7. Gribble, G. W. 1992. Naturally occurring organohalogen compounds--a survey. J. Nat. Prod. 55:1353-1395.

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Edited by Lori Joy Nacario, student of Rachel Larsen and Kit Pogliano