Burkholderia xenovorans: Difference between revisions

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


The genome size of ''Burkholderia xenovorans'' varies between 7.4 to 9.3 Mbp, depending upon the particular strain.  ''Burkholderia xenovorans'' has three circular replicons: chromosome 1 at 4.90 Mbp and chromosome 2 at 3.36 Mbp and a megaplasmid at 1.47 Mbp.  Chromosome 1 contains homologs of dnaA (a chromosomal replication initiation protein) and dnaN (a DNA polymerase subunit).  Chromosome 2 contains genes important for plasmid replication and partitioning, as well as other genes that help ''Burkholderia xenovorans'' adapt to it environmental niche.  Unlike the chromosomes, the megaplasmid at 1.47 Mbp does not contain any essential functions or RNA.
The genome size of ''Burkholderia xenovorans'' varies between 7.4 to 9.3 Mbp, depending upon the particular strain.  ''Burkholderia xenovorans'' has three circular replicons: chromosome 1 at 4.90 Mbp and chromosome 2 at 3.36 Mbp and a megaplasmid at 1.47 Mbp.  Chromosome 1 is considered to be the major chromosome as it carries the DNA for major cellular functions such as DNA replication and translation.  Chromosome 2 contains genes important for plasmid replication and partitioning, as well as other genes that help ''Burkholderia xenovorans'' adapt to it environmental niche.  Unlike the chromosomes, the megaplasmid at 1.47 Mbp does not contain any essential functions or RNA. Instead, the megaplasmid carries unique metabolic capabilities that differ from strain to strain of ''Burkholderia xenovorans.'' [1]


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


''Burkholderia xenovorans'' is an aerobic gram-negative bacteria that is catalase- and oxidase-positive.  The most interesting feature of ''Burkholderia xenovorans'' is its ability to catabolize aromatic compounds, such as those that come out of roots or involved in root turnover.  Degradation of aromatic compounds usually involves an initial ring activation through either a hydroxylation by an oxygenase or a CoA ligase-mediated pathway.  The aromatic compound then is shunted to one of several different catabolic pathways, depending on the substrate.   
''Burkholderia xenovorans'' is an aerobic gram-negative bacteria that is catalase- and oxidase-positive.  The most interesting feature of ''Burkholderia xenovorans'' is its ability to catabolize aromatic compounds, such as those that come out of roots or involved in root turnover.  Degradation of aromatic compounds usually involves an initial ring activation through either a hydroxylation by an oxygenase or a CoA ligase-mediated pathway.  The aromatic compound then is shunted to one of several different catabolic pathways, depending on the substrate.  [1]


''Burkholderia xenovorans'' contains nitrogen fixation genes, which are located on chromosome 2, which can be used to change elemental nitrogen.  ''Burkholderia xenovorans'' also contains chemotaxis genes which allow it to move toward aromatic compounds in the soil rhizosphere.
''Burkholderia xenovorans'' contains nitrogen fixation genes, which are located on chromosome 2, which can be used to change elemental nitrogen.  ''Burkholderia xenovorans'' also contains chemotaxis genes which allow it to move toward aromatic compounds in the soil rhizosphere. [1]


==Ecology==
==Ecology==
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==Pathology==
==Pathology==


''Burkholderia xenovorans'' is not known to cause any disease in humans or animals, and it lacks the genetic virulence features present in ''Burkholderia cenocepacia'', which is an opportunistic pathogen in patients with cystic fibrosis and certain granulomatous diseases. [1] Burkholderia species have experimentally been implicated in having some virulence factors (e.g. resistance to the antimicrobial Polymixin B, presence of a flagella, reactive oxygen species resistance), but those traits can also be useful in their ecological niche.
''Burkholderia xenovorans'' is not known to cause any disease in humans or animals, and it lacks the genetic virulence features present in ''Burkholderia cenocepacia'', which is an opportunistic pathogen in patients with cystic fibrosis and certain granulomatous diseases. [2] Burkholderia species have experimentally been implicated in having some virulence factors (e.g. resistance to the antimicrobial Polymixin B, presence of a flagella, reactive oxygen species resistance), but those traits can also be useful in their ecological niche. [1]


==Application to Biotechnology==
==Application to Biotechnology==
Does this organism produce any useful compounds or enzymes?  What are they and how are they used?
 
The aerobic degradative of aromatic capabilities of ''Burkholderia xenovorans'' holds great potential for environmental biotechnological applications.  Bioremediation is the use of organisms (micro- or otherwise) to break down toxic pollutants and compounds into non-toxic non-harmful compounds. [3] However, the challenge will be to manage microorganisms such as ''Burkholderia xenovorans'' and seed them into target PCB-contaminated environments and have them effectively change the contaminants into non-harmful compounds in a enviromentally cost-effective and sustainable manner. [4] Also, microbial factors must be evaluated (chemotaxis, surface adherence, etc.) to maximize interaction between pollutants and the bacteria and therefore increase the net breakdown of the pollutants into non-harmful compounds. [4]


==Current Research==
==Current Research==
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==References==
==References==


1. Chain, P., Denef, V., Knstantinidis, K., et al. Burkholderia xenovorans LB400 harbors a multi-replicon, 9.73-Mbp genome shaped for versatility. Proc Natl Acad Sci U S A. 2006 October 17; 103(42): 15280–15287.  
1. Chain, P., Denef, V., Knstantinidis, K., et al. Burkholderia xenovorans LB400 harbors a multi-replicon, 9.73-Mbp genome shaped for versatility. Proc Natl Acad Sci U S A. 2006 October 17; 103(42): 15280–15287.  


2. Petrucca A, Cipriani P, Sessa R, Teggi A, Pustorino R, Santapaola D, et al. Burkholderia cenocepacia vaginal infection in patient with smoldering myeloma and chronic hepatitis C. Emerg Infect Dis. http://www.cdc.gov/ncidod/EID/vol10no11/04-0127.htm. 2004 November.
2. Petrucca A, Cipriani P, Sessa R, Teggi A, Pustorino R, Santapaola D, et al. Burkholderia cenocepacia vaginal infection in patient with smoldering myeloma and chronic hepatitis C. Emerg Infect Dis. http://www.cdc.gov/ncidod/EID/vol10no11/04-0127.htm. 2004 November.
3. Chavez, F., Gordillo, F., and Jerez, C. Adaptive responses and cellular behaviour of biphenyl-degrading bacteria toward polychlorinated biphenyls. Biotechnology Advances, Volume 24, Issue 3, May-June 2006. p.309-320.
4. Verstraete, W. Microbial ecology and environmental technology (''Commentary''). The ISME Journal (2007) 1, 4–8; doi:10.1038/ismej.2007.7


[Sample reference] [http://ijs.sgmjournals.org/cgi/reprint/50/2/489 Takai, K., Sugai, A., Itoh, T., and Horikoshi, K. "''Palaeococcus ferrophilus'' gen. nov., sp. nov., a barophilic, hyperthermophilic archaeon from a deep-sea hydrothermal vent chimney". ''International Journal of Systematic and Evolutionary Microbiology''. 2000. Volume 50. p. 489-500.]
[Sample reference] [http://ijs.sgmjournals.org/cgi/reprint/50/2/489 Takai, K., Sugai, A., Itoh, T., and Horikoshi, K. "''Palaeococcus ferrophilus'' gen. nov., sp. nov., a barophilic, hyperthermophilic archaeon from a deep-sea hydrothermal vent chimney". ''International Journal of Systematic and Evolutionary Microbiology''. 2000. Volume 50. p. 489-500.]


Edited by student of [mailto:ralarsen@ucsd.edu Rachel Larsen]
Edited by student of [mailto:ralarsen@ucsd.edu Rachel Larsen]

Revision as of 03:21, 27 August 2007

A Microbial Biorealm page on the genus Burkholderia xenovorans

Classification

Higher order taxa

Bacteria; Proteobacteria; Betaprotobacteria; Burkholderiales; Burkholderiaceae; Burkholderia

Burfu.jpg

Species

NCBI: Taxonomy

Genus species

Burkholderia xenovorans

Description and significance

Burkholderia xenovorans is an important aerobic degrader of polychlorinatred biphenyl (PCB), which is an organic chemical that has industrial use but is toxic to animals and humans. The LB400 strain is the most studied strain due to its ability to oxidize over 20 different PCB congeners. It was isolated in a landfill contaminated by PCB in New York over 20 years ago. Burkholderia xenovorans' environmental niche is in soil rhizospheres, which is the soil area surrounding plant roots. [1]

Genome structure

The genome size of Burkholderia xenovorans varies between 7.4 to 9.3 Mbp, depending upon the particular strain. Burkholderia xenovorans has three circular replicons: chromosome 1 at 4.90 Mbp and chromosome 2 at 3.36 Mbp and a megaplasmid at 1.47 Mbp. Chromosome 1 is considered to be the major chromosome as it carries the DNA for major cellular functions such as DNA replication and translation. Chromosome 2 contains genes important for plasmid replication and partitioning, as well as other genes that help Burkholderia xenovorans adapt to it environmental niche. Unlike the chromosomes, the megaplasmid at 1.47 Mbp does not contain any essential functions or RNA. Instead, the megaplasmid carries unique metabolic capabilities that differ from strain to strain of Burkholderia xenovorans. [1]

Cell structure and metabolism

Burkholderia xenovorans is an aerobic gram-negative bacteria that is catalase- and oxidase-positive. The most interesting feature of Burkholderia xenovorans is its ability to catabolize aromatic compounds, such as those that come out of roots or involved in root turnover. Degradation of aromatic compounds usually involves an initial ring activation through either a hydroxylation by an oxygenase or a CoA ligase-mediated pathway. The aromatic compound then is shunted to one of several different catabolic pathways, depending on the substrate. [1]

Burkholderia xenovorans contains nitrogen fixation genes, which are located on chromosome 2, which can be used to change elemental nitrogen. Burkholderia xenovorans also contains chemotaxis genes which allow it to move toward aromatic compounds in the soil rhizosphere. [1]

Ecology

Burkholderia xenovorans' ability to fix nitrogen make it an important symbiont for plants to thrive in nitrogen-poor soil.

        • NEED TO WORK ON SOME MORE****

Pathology

Burkholderia xenovorans is not known to cause any disease in humans or animals, and it lacks the genetic virulence features present in Burkholderia cenocepacia, which is an opportunistic pathogen in patients with cystic fibrosis and certain granulomatous diseases. [2] Burkholderia species have experimentally been implicated in having some virulence factors (e.g. resistance to the antimicrobial Polymixin B, presence of a flagella, reactive oxygen species resistance), but those traits can also be useful in their ecological niche. [1]

Application to Biotechnology

The aerobic degradative of aromatic capabilities of Burkholderia xenovorans holds great potential for environmental biotechnological applications. Bioremediation is the use of organisms (micro- or otherwise) to break down toxic pollutants and compounds into non-toxic non-harmful compounds. [3] However, the challenge will be to manage microorganisms such as Burkholderia xenovorans and seed them into target PCB-contaminated environments and have them effectively change the contaminants into non-harmful compounds in a enviromentally cost-effective and sustainable manner. [4] Also, microbial factors must be evaluated (chemotaxis, surface adherence, etc.) to maximize interaction between pollutants and the bacteria and therefore increase the net breakdown of the pollutants into non-harmful compounds. [4]

Current Research

Enter summaries of the most recent research here--at least three required

References

1. Chain, P., Denef, V., Knstantinidis, K., et al. Burkholderia xenovorans LB400 harbors a multi-replicon, 9.73-Mbp genome shaped for versatility. Proc Natl Acad Sci U S A. 2006 October 17; 103(42): 15280–15287.

2. Petrucca A, Cipriani P, Sessa R, Teggi A, Pustorino R, Santapaola D, et al. Burkholderia cenocepacia vaginal infection in patient with smoldering myeloma and chronic hepatitis C. Emerg Infect Dis. http://www.cdc.gov/ncidod/EID/vol10no11/04-0127.htm. 2004 November.

3. Chavez, F., Gordillo, F., and Jerez, C. Adaptive responses and cellular behaviour of biphenyl-degrading bacteria toward polychlorinated biphenyls. Biotechnology Advances, Volume 24, Issue 3, May-June 2006. p.309-320.

4. Verstraete, W. Microbial ecology and environmental technology (Commentary). The ISME Journal (2007) 1, 4–8; doi:10.1038/ismej.2007.7


[Sample reference] Takai, K., Sugai, A., Itoh, T., and Horikoshi, K. "Palaeococcus ferrophilus gen. nov., sp. nov., a barophilic, hyperthermophilic archaeon from a deep-sea hydrothermal vent chimney". International Journal of Systematic and Evolutionary Microbiology. 2000. Volume 50. p. 489-500.

Edited by student of Rachel Larsen