DESCRIPTION OF THE PHYLUM EPSILONPROTEOBACTERIA (STACKENBRANDT ET AL. 1988)
| EUBACTERIA> PROTEOBACTERIAE> EPSILONPROTEOBACTERIA |
PHYLUM EPSILONPROTEOBACTERIA LINKS
| Epsilonproteobacteria (ep-si-lon-PRO-te-o-bak-TE-re-uh) is derived from two Greek roots and a Greek letter meaning “epsilon” (ε) “changeable” (proteakos -πρωτεϊκός) “little stick” (bakterion -βακτήριον). The name is in reference to Proteus, the name of a Greek sea god who could change his shape (Stackebrandt et al. 1988). |
| INTRODUCTION TO THE EPSILONPROTEOBACTERIA Epsilonproteobacteria are unicellular Gram negative (text with tooltip) A Gram - cell loses the blue-black crystal-violet color following destaining with alcohol during the Gram Stain procedure. Then, it takes on the color of the counterstain, typically iodine. rods (text with tooltip) A rod is an elongate cell form such that it has distinct ends (called poles). or spirals (text with tooltip) A spiral is a cell form that is a cork-screw shaped rod. , with single, unsheathed polar flagella (text with tooltip) Polar flagella are those that emerge from the poles of the cell (rods or spirals). . Organisms in this group are poorly understood, but they seem to constitute major microbial constituents of sulfur-rich hydrothermal vent and microbial mat communities (Figure 1). In addition, some taxa like Helicobacter (Figure 2) seem to be opportunistic pathogens that live as “quiet” infections in places like the gums and stomach, where under some circumstances, can cause periodontal disease and stomach ulcers, respectively. A symbiotic relationship has been reported between a snail of hydrothermal vents and a member of this phylum. Stackebrandt et al. (1988), using 16S rRNA sequences, defined a seemingly unrelated group of eubacteria as Proteobacteria, the purple bacteria, which they defined as a class that they called Proteobacteria. Within that group, they defined five separate lines, each defined by a Greek letter: α, β, γ, δ, ε. The second edition of Bergey’s Manual of Systematic Bacteriology (Garrity et al. 2003) adopted Proteobacteria, but raised it to phylum level with each of the five groups becoming classes. In order to bring the prokaryotes into line with kingdom-level divisions in the eukaryotes, we felt that it was necessary to raise the Proteobacteria to kingdom-level status with each of the five groups also raised to the level of phylum. The Epsilonproteobacteria is perhaps the least well known of the five phyla. Garrity et al. (2003) has only a single order (Campylobacteriales). Campbell et al. (2006) added Nautiliales and four other unnamed orders. Clearly, the structure of this phylum is more diverse than its current structure would indicate. |
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| FIGURE 1. Photograph of a microbial mat from White Sulfur Springs, Louisiana. Image from http://www.geol.lsu.edu/aengel/epsilon.htm | FIGURE 2. Helicobacter pylori, the causative agent of peptic ulcers. (left) SEM micrograph of Helicobacter in the mucosa of the stomach. (right) TEM micrograph of Helicobacter showing the flagella. Left Image from NIH and in the Public Domain Right Image by Yutaka Tsutsumi, Wikimedia Commons |
FIGURE 3. Topology of the Proteobacteria with the relationships of the phyla and the single class of the Epsilonproteobacteria (in shaded box).
| LITERATURE CITED Black, J. G. 2002. Microbiology, Principles and Explorations. 5th ed. John Wiley and Sons, Inc. New York. Brock, T. D., M.T. Madigan, J.M. Martinko, and J. Parker. 1994. Biology of Microorganisms. 7th ed. Prentice Hall. Englewood Cliffs, NJ. Emerson, D., J. A. Rentz, T. G. Lilburn, R. E. Davis, H. Aldrich, C. Chan, and C. L. Moyer. 2007. A novel lineage of Proteobacteria involved in formation of marine Fe-oxidizing microbial mat communities. PLoS ONE. 2007 (8): e667. http://www.plosone.org Gao, B. and R. S. Gupta. 2007. Phylogenetic analysis of proteins that are distinctive of Archaea and its main subgroups and the origin of methanogenesis. BMC Genomics. 8:86. http://www.biomedcentral.com/1471-2164/8/86. Garrity, G. M., M. Winters, and D. Searles. 2001. Bergey’s manual of systematic bacteriology. 2nd ed. Springer-Verlag. New York. Garrity, G. M., J. A. Bell, and T. G. Lilburn. 2003. Taxonomic Outline of the Prokaryotes. Bergey’s Manual of Systematic Bacteriology. 2nd edition. Release 4.0. Springer-Verlag. New York. pp. 1-397. Margulis, L. and K. Schwartz. 1988. Five kingdoms, an illustrated guide to the phyla of life on earth. 2nd Edition. W. H. Freeman and Co. New York. Margulis, L. and K. Schwartz. 1998. Five kingdoms, an illustrated guide to the phyla of life on earth. 3rd Edition. W. H. Freeman and Co. New York. Stackebrandt, E., R. G. E. Murray, and H. G. Trüper. 1988. Proteobacteria classis nov., a name for the phylogenetic taxon that includes the “Purple Bacteria and Their Relatives”. International Journal of Systematic Bacteriology. 38(3): 321-325. Tudge, C. 2000. The Variety of Life, A Survey and a Celebration of all the Creatures That Have Ever Lived. Oxford University Press. New York. Williams, K. P., B. W. Sobral, and A. W. Dickerman. 2007. A robust species tree for the Alphaproteobacteria. Journal of Bacteriology. 189(13): 4578-4586. Woese, C. R. and G. E. Fox. 1977. Phylogenetic structure of the prokaryotic domain: the primary kingdoms. Proceedings of the National Academy of Sciences USA. 74:5088-5090. Woese, C. R., O. Kandler, and M. L. Wheelis. 1990. Towards a natural system of organisms: Proposal for the domains Archaea, Bacteria, and Eucarya. Proc. Natl. Acad. Sci. USA. 87: 4576-4579. |
| By Jack R. Holt. Last revised: 02/20/2013 |
