1 / 17

Analysis of atmospheric oxygen tolerance in methanogens

Analysis of atmospheric oxygen tolerance in methanogens. By Jill Jackson. Introduction. Methanogens are: Archaea Anaerobic Extremophiles. CO 2 + 4 H 2  CH 4 + 2H 2 O. Why study methanogens?. Martian Conditions Dry Cold Oxidizing Low pressure Abundance of CO 2. Purpose.

neviah
Download Presentation

Analysis of atmospheric oxygen tolerance in methanogens

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Analysis of atmospheric oxygen tolerance in methanogens By Jill Jackson

  2. Introduction Methanogens are: • Archaea • Anaerobic • Extremophiles • CO2 + 4 H2 CH4 + 2H2O

  3. Why study methanogens? Martian Conditions • Dry • Cold • Oxidizing • Low pressure • Abundance of CO2

  4. Purpose • Can Methanosarcina barkeri and Methanothermobacter wolfeii recover after atmospheric O2 exposure? • True oxygen tolerance or effect of reducing agent? • How do they survive?

  5. Methods • Optical density measurements • Oxygen exposure times: 0, 2, 3, 4, 5, and 8 • hours • Cultures exposed to atmospheric O2 both • with and without Na2S

  6. Methods (cont.) • Incubation in ideal conditions • Analysis using GC (gas chromatography)

  7. Results: M. wolfeii Optical Density Measurements

  8. Results: M. barkeri Optical Density Measurements

  9. Results Summary • Role of Na2S • Implications of expanded research capabilities • Two other possible factors • SOD • Cellular Aggregation • Do some strains of methanogens have a limited intrinsic tolerance to oxygen?

  10. What is an SOD? • Superoxide dismutase • Role in oxidative stress • O2- radical damage • Findings by Brioukhanov et. al.

  11. Cellular Aggregation Findings by Kato et. al. indicate increased O2 tolerance of M. barkeri in aggregates

  12. Conclusion • Methanogens exhibited survival in the absence of Na2S • Some strains of methanogens have a limited intrinsic tolerance to oxygen • Aggregation also likely affects survival • Shorter exposure, faster recovery

  13. Future Work • Analysis of oxygen tolerance at various optical densities • Oxygen tolerance analysis of additional strains of methanogens

  14. References • Brioukhanov, A., Netrusov, A., Sordel, M., Thauer, R.K., and S.Shima. 2000. Protection of Methanosarcina barkeri against oxidative stress: identification and characterization of an iron superoxide dismutase. Arch. Microbiol. 174: 213-216. • Cannio, R., Fiorentino, G., Morana, A., Rossi, M., and S. Bartolucci. 2000. Oxygen: Friend of Foe? Archaeal Superoxide Dismutases in the Protection of Intra- and Extracellular Oxidative Stress. Frontiers in Bioscience. 5:768-779. • Kato, M.T., Field, J.A., and G. Lettinga. 1997. Anaerobe Tolerance to Oxygen and the Potentials of Anaerobic and Aerobic Cocultures for Wastewater Treatment. Braz. J. Chem. Eng. 14. • Kral, T.A., Bekkum, C.R., and McKay, C.P. 2004. Growth of Methanogens on a Mars Soil Simulant. Orig. of Life and Ev. of the Biosphere. 34: 615-626. • Reeve, J.N. 1992. Molecular Biology of Methanogens. Annu. Rev. Microbiol., 46: 165-191. • http://dutch.phys.strath.ac.uk/CommPhys2001Exam/David_Speirs/climateandweather.htm

  15. Photos • http://www.genomenewsnetwork.org/articles/07_03/extremo.shtml • www.ccfc.ca/English/ images/gut.gif • www.myeloperoxidase.com/ FeSOD/images/FeSOD.jpg • www.backdrops.net/ Rent%20Backdrops%20p.1.htm • http://www.jpl.nasa.gov/news/features.cfm?feature=533 • www.myeloperoxidase.com/ FeSOD/planta.html • http://genome.jgi-psf.org/draft_microbes/metba/metba.home.html • http://biology.kenyon.edu/Microbial_Biorealm/archaea/methanothermobacter/methanothermobacter.html

  16. Acknowledgements

  17. Questions?

More Related