Domain Archaea; Phylum Euryarchaeota; Class Archaeoglobi; Order Archaeoglobales; Family Archaeoglobaceae [Others may be used. Use NCBI link to find]
Description and Significance
G. ahangari is an anaerobic, coccoid-shaped member of Archaea that ranges from 0.3-0.5 micrometers in diameter. 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.
Not a lot of information is available on the genome of Geoglobus ahangari. The DNA is known to be about 58.7% GC. By analysis of the 16S DNA, G. ahangari's two closest relatives are believed to be A. fulgidus and A. profundus, with a 96.2% and 94.1% similarity, respectively.
Cell Structure, Metabolism and Life Cycle
Geoglobus ahangari can operate in an autotrophic sense by using hydrogen as an electron donor while reducing Fe(III) oxide. This process produces extracellular waste in the form of magnetite.
Ecology and Pathogenesis
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. This autotrophy with use of Fe(III) oxide results in the accumulation of magnetite.
This organism is susceptible to the antibiotics: trimethoprim, rifampicin, ampicillin, chloramphenicol, penicillin G, and phosphyomycin at all at different concentrations for each. However, cycloheximide, kanamycin, streptomycin, puromycin, novobiocin, and neomycin sulfate failed to inhibit growth of G. ahangari.
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". International Journal of Systematic and Evolutionary Microbiology". May 2002; 52: 719 - 728.
Slobodkina GB, Kolganova TV, Querellou J, Bonch-Osmolovskaya EA, Slobodkin AI. "Geoglobus acetivorans sp. nov., an iron(III)-reducing archaeon from a deep-sea hydrothermal vent". "International Journal of Systematic and Evolutionary Microbiology". 2009. Volume 59. p. 2880-2883.
Page authored by Abigail Entz and Sara Dolmetsch, students of Prof. Jay Lennon at Michigan State University.
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