DESCRIPTION OF THE PHYLUM ANOXYBACTERIA (MARGULIS AND SCHWARTZ 1988)
| EUBACTERIA> FIRMICUTAE> ANOXYBACTERIA |
PHYLUM ANOXYBACTERIA LINKS
| Anoxybacteria (pronounced: an-OX-i-bak-TE-re-uh) is derived from three Greek roots that mean “without” (an -αν) “acid” (oxy -οξύ) and “little stick” (bakterion -βακτήριον). Oxy in the old sense meant acidic or sharp tasting. Lavoisier used it in this way when he named the element Oxygen. He mistakenly thought that oxygen was the acid maker. The meaning here is that the taxa in this phylum live without oxygen. |
| INTRODUCTION TO THE ANOXYBACTERIA The Anoxybacteria, also called Clostridia by Garrity et al. (2001) are rods and cocci that utilize anaerobic fermentation, but some are capable of tolerating some ambient oxygen. They have very limited synthetic abilities. For example, they are unable to synthesize porphyrins. Clostridia can ferment a wide array of organic compounds, and their fermentation products are quite varied. Usually, they produce small organic acids, ethanol, CO2, NH3, and sometimes H2. Though this group is poorly known (Collins et al. 1994), Clostridia occur almost anywhere there is an environment that is anaerobic and rich in organics. That includes soil and anaerobic sediments. Also, many have developed important mutualistic symbioses in animals that ferment their foods. Indeed, they are found as non-pathogenic members of the intestinal floras of animals in general. Some are nitrogen-fixers. Many taxa have been documented as endophytes, microbes living within a plant host without apparent harm to the host (Saito et al. 2008). Organisms like Clostridium (e.g. C. botulinum, and C. tetane, causative agents of botulism and tetanus, respectively, Figure 1) can live as parasites and release very powerful toxins. Botulism is a life-threatening disease in which the endotoxin produced by the organism paralyses striated muscle. Wenham and Cohen (2008) define three points of entry for the toxin: a wound, food, intestinal flora. In the case of a wound, spores of the microbe gain entry into the body and begin to grow. As they grow, toxin is released which is carried to the rest of the body. Tetanus, caused by C. tetane, also gains entry and manifests itself the same way. Canned foods can provide the perfect anaerobic environment for the growth of C. botulinum. Upon ingestion, the toxin, which has been pre-formed in the food, is taken up and can have rapid, acute effects (Wenham and Cohen 2008, McLaughlin et al. 2006). Clostridium botulinum can also begin to grow in the intestine, especially in the case of infants who have not developed a stable intestinal community. In this case, too, the microbe does not invade the body but does release toxins that can lead to sudden death. The strength of botulism toxin is astounding. Indeed, it appears to be the most poisonous biological substance known (Arnon et al. 2001) and operates by aggressive enzymatic interference with the release of acetylcholine in the synapse. According to Schantz and Johnson (1992) the minimum lethal dose for botulism toxin is 0.00003 µg/kg and for tetanus toxin is 0.0001 µg/kg in mice (For perspective, potassium cyanide has a lethal dose of 100-200 mg/kg making botulism toxin nearly a billion times more effective than cyanide). The extreme toxicity of botulism toxin has made it a prime candidate as a biological weapon (Arnon et al. 2001). However, the toxin is difficult to maintain and disperse as an aerosol. Its use was attempted by a Japanese cult between 1992 and 1995, but they failed. However, the toxin could be used as a terror weapon to taint in drinking water and food supplies. Even the most dangerous of bioactive compounds are not without potential benefits. Botulism toxin, licensed under the name Botox, has had therapeutic success in causing muscles to relax in the treatment of line and creases (glabellar lines) on the face (Carruthers, et al. 2002). Beyond cosmetic uses, botox can be used for many chronic conditions like migraine headaches (Naumann et al. 2008) and spasms (Bihari 2005). This is a modification of Barnes (1984b) and Margulis and Schwartz (1988) in which the phylum is designated M-14. Margulis and Schwartz (1998) lumped these taxa together with the Aerendosporobacteria as the Phylum Endospora (B-10). We have chosen to retain the separation and regard the taxon Endospora as a superphylum within the Kingdom Firmicutae. Bergey’s Manual of Systematic Bacteriology, volume 2, sections 12, 13 and 14 (Holt, 1986) describe the taxa which I include in the Anoxybacteria. Section 12 (The Gram-Positive Cocci). Section 13 (Endospore-forming Gram-Positive Rods and Cocci, in part) includes taxa which we place in the Class Clostridiae. Bergey’s Manual of Systematic Bacteriology, 2nd edition (Garrity et al. 2001) treats the taxa that we include in the Anoxybacteria as a class (“Clostridia”) of phylum Firmicutes (BXIII). The All Species Living Tree Project (Yarza et al. 2008 and 2010; Munoz et al. 2011) suggests a need for the revision of the taxa included in the Anoxybacteria. For example, they demonstrate that the genus, Clostridium is polyphyletic. |
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| FIGURE 1. SEM micrograph of Clostridium botulinum, the causative agent of botulism. Image from CDC, in the Public Domain |
FIGURE 2. Tentative relationships between the phyla of the Firmicutes that we use in this system. The tentative location of the anoxybacteria is indicated by the shaded box. This tree uses Margulis and Schwartz (1998), with modifications from Garrity et al. (2001, 2003, and 2005), Tudge (2000), and Black (2002) in its structure.
| LITERATURE CITED Arnon, S. S., R. Schechter, T. V. Inglesby, D. A. Henderson, J. G. Bartlett, M. S. Ascher, E. Eitzen, A. D. Fine, J. Hauer, M. Layton, S. Lillibridge, M. T. Osterholm, T. O’Toole, G. Parker, T. M. Perl, P. K. Russell, D. L. Swerdlow, K. Tonat. 2001, Botulism toxin as a biological weapon: Medical and public health management. JAMA. 285(8): 1059-1070. Barnes, R. S. K. 1984b. Kingdom Monera. IN: Barnes, R.S.K., ed. A synoptic classification of living organisms. Sinauer Associates. Sunderland, Mass. Bihari K. 2005. Safety, effectiveness, and duration of effect of BOTOX after switching from Dysport for blepharospasm, cervical dystonia, and hemifacial spasm dystonia, and hemifacial spasm. Curr. Med. Res. Opin. 21(3): 433–8. 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. Carruthers, J. A., N. J. Lowe, M. A. Menter, J. Gibson, M. Nordquist, J. Mordaunt, P. Walker, and N. Eadie. 2002. A multicenter, double-blind, randomized, placebo-controlled study of the efficacy and safety of botulism toxin type A in the treatment of glabellar lines. J. Am. Acad. Dermatol. 46(6): 840-849. Collins, M. D., P. A. Lawson, A. Willems, J. J. Cordoba, J. Fernandez-Garayzabal, P. Garcia, J. Cai, H. Hippe, and J. A. E. Farrow. 1994. The phylogeny of the genus Clostridium: proposal of five new genera and eleven new species combinations. International Journal of Systematic Bacteriology. 44(4): 812-826. 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. Krieg, N. R. 1984. Gram-negative aerobic rods and cocci. In: Krieg, N. R. and J. G. Holt, eds. Bergey´s Manual of Systematic Bacteriology, Vol. 1: 140-408. 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. McLaughlin, J., K. A. Grant, and C. L. Little. 2006. Food-borne butulism in the United Kingdom. Journal of Public Health. 28(4): 337-342. Naumann M., Y. So, C. E. Argoff, M. K. Childers, D. D. Dykstra, G. S. Gronseth, B. Jabbari, H. C. Kaufmann, B. Schurch, S. D. Silberstein, and D. M. Simpson. 2008. Assessment: Botulinum neurotoxin in the treatment of autonomic disorders and pain (an evidence-based review): report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology. Neurology. 70 (19): 1707–14. Saito, A., M. Kawahara, S. Ikeda, M. Ishimine, S. Akao, and K. Minamisawa. 2008. Broad distribution and phylogeny of anaerobic endophytes of Cluster XIVa Clostridia in plant species including crops. Microbes. Environ. 23(1): 73-80. Shantz, E. J. and E. A. Johnson. 1992. Microbiological Reviews. 56(1): 80-99. 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. Wenham, T. and A. Cohen. 2008. Botulism. Continuing Education in Anesthesia. Critical Care and Pain. 8(1): 21-25. |
| By Jack R. Holt. Last revised: 02/11/2013 |
