Domain Archaea; Phylum Euryarchaeota; Class Archaeoglobi; Order Archaeoglobales; Family Archaeoglobaceae [Others may be used. Use NCBI link to find]
Description and Significance
Describe the appearance, habitat, etc. of the organism, and why you think it is important.
G. ahangari is an anaerobic, coccoid-shaped member of Archaea. As seen under phase contrast microscopy, the cells are usually found alone or in couples and all have a single flagellum that is used for movement (mainly tumbling motility). Transmission Electron Microscopy releaved that the cell membranes of G. ahangari are similar to other members of Archaea, possesing three layers- a cytoplasmic membrane, a periplasmic space and a layer on the outer surface. It is a hyperthermophile that can grow both autotrophically or chemoorganotrophically depending on the available electron sources. G. ahangari is biologically and ecologically significant because it was the first anaerobe isolated that had the ability to use long-chain fatty acids as a source of energy. It was also the first archaeon cultured to have the ability to generate energy from the coupling of hydrogen gas to the reduction of iron. Geoglobus ahangari is most closely related to members of Ferroglobus and Archaeoglobus, though G. ahangari does not have fluorescent properties.
Describe the size and content of the genome. How many chromosomes? Circular or linear? Other interesting features? What is known about its sequence?
Cell Structure, Metabolism and Life Cycle
Interesting features of cell structure; how it gains energy; what important molecules it produces.
Ecology and Pathogenesis
Habitat; symbiosis; biogeochemical significance; contributions to environment.
If relevant, how does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.
G. ahangari was originally obtained from a hydrothermal vent at a depth of 2000 meters in Guaymas Basin in the Gulf of California. This organism can be isolated using a relatively new technique of incorporating iron oxide into solid medium to be used as an electron acceptor. The environmental ranges for G. ahangari were measured in the lab to be 65-90°C for temperature, 5.0-7.6 for pH, and 9.0-38 g/l NaCl for salinity. Optimal grown occurred at 88°C and a pH of 7.0.
The biogeochemical significance of G. ahangari is related to it's ability to use hydrogen emitted from geothermal marine vents as an electron donor when coupled to iron reduction.
[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.
[http://ijs.sgmjournals.org/cgi/reprint/52/3/719 K. Kashefi, J. M. Tor, D. E. Holmes, C. V. Gaw Van Praagh, A. L. Reysenbach, and D. R. Lovley Geoglobus ahangari gen. nov., sp. nov., a novel hyperthermophilic archaeon capable of oxidizing organic acids and growing autotrophically on hydrogen with Fe(III) serving as the sole electron acceptor Int J Syst Evol Microbiol, May 2002; 52: 719 - 728.]
Page authored by _____, student of Prof. Jay Lennon at Michigan State University.
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