DESCRIPTION OF THE KINGDOM SAPROSPIRAE AND ITS SINGLE PHYLUM SAPROSPIROBACTERIA (MARGULIS AND SCHWARTZ 1998)
| EUBACTERIA> PROTEOBACTERIAE> SAPROSPIRAE> SAPROSPIROBACTERIA |
KINGDOM SAPROSPIRAE LINKS
| Saprospirae (sap-ro-SPI-re) is formed from a Greek roots which mean rotten (sapros -σαπρός) and a Latin root that means spiraled (spira). The name describes the nature of Saprospira, the genus after which the kingdom was named. |
| INTRODUCTION TO THE KINGDOM SAPROSPIRAE AND ITS SINGLE PHYLUM, SAPROSPIROBACTERIA These are 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). that occur singly or in filaments (text with tooltip) A filament is a linear array of cells. In the Cyanobacteria, a filament is the linear array of cells (trichome) plus the surrounding mucilaginous sheath. . Usually they occur within a layer of polysaccharide slime through which they can glide. Thus the common name for the group is the gliding bacteria. Although they are aerobic, they do not have catalase, and, therefore cannot tolerate oxygen-rich environments (Schmidt et al. 1987). Otherwise, they are typical aerobes with a well-developed citric acid cycle (text with tooltip) The citric acid cycle (also called the Krebs cycle or tricarboxylic acid cycle) is a fundamental set of reactions that occur in aerobic metabolism, particularly in the mitochondrion. Acetyl Co A, which is derived from pyruvate is completely oxidized to CO2 and reduces NAD and FAD. and cytochrome system; thus, they release CO2 as a consequence of respiration. Most of them live in environments that intersect aerobic and anaerobic habitats, usually soils or aquatic sediments, though some may be parasites or commensals. Cytophaga (Figure 1) and its relatives are important cellulose decomposers in soil and water. They are slender, single rods, and sometimes in in chains, but never form fruiting bodies. They may make cysts, some are facultative anaerobes and ferment carbohydrates to organic acids; usually aerobic decomposers of chitin and cellulose; in soil and aquatic systems, some parasites of fish. Beggiatoa (Figure 2) and members of the Beggiatoiales may be straight or helical filaments that are sessile and attached or mobile. Typically, they reproduce by the random fragmentation of the filaments. Some of this group oxidize H2S with the deposition of internal S granules (chemoautotrophic or chemoheterotrophic (text with tooltip) Chemoheterotrophs are those organisms that use compounds from the environment to provide metabolic energy. ). They can also be autotrophic or mixotrophic (text with tooltip) A mixotrophic organism obtains food either by autotrophic or saprobic means. Also called mesotrophic. and fix CO2 with the oxidation of inorganic sulfur. Typically, they occur in organically-enriched muds of aquatic systems as well as the oral cavities of animals. Beggiatoa can be a major problem in sewage treatment plants where the slime layer causes the formation of large aggregates that can plug up intakes and filtration systems. Both Beggiatoa and Thioploca (Figure 3) are similar (Maier 1980) in that they glide, metabolize sulfur, and are quite large as bacteria go. Indeed, Thioploca is gigantic and can have cells that are 160µm wide (Ahmad et al. 1999). They live in sediment and glide into the sulfur-rich mud and back out to the nitrogen-rich water. Ahmad et al. (1999) found that Thioploca, which has a cell vacuole that occupies 80% of the cell volume, could store concentrations of nitrate up to 500nM. Thus, Thioploca must be a major player in the marine and freshwater nitrogen and sulfur cycles. Ours is a modification of Margulis and Schwartz (1998) who separate the gliding bacteria (Saprospirobacteria B-6) from the fruiting bacteria (Myxobacteria) based on 16S rRNA studies (see Figure 4). Bergey’s Manual of Systematic Bacteriology, volume 3, section 23 (Holt 1989a; Nonphotosynthetic, Nonfruiting Gliding Bacteria) includes the taxa which we place in the Class Cytophagatiae. Bergey’s Manual of Systematic Bacteriology, 2nd edition (Garrity et al. 2001) treats the taxa that we include in the Saprospirae as a group within the Gammaproteobacteria together with a separate phylum (Phylum B XX. “Bacteroidetes”). Almost certainly this as presented is a paraphyletic group, and the taxa will be revised as information becomes available. Topologies generated by the All Species Living Tree Project (Yarza et al. 2008 and 2010; Munoz et al. 2011; Figure 5) suggest a much more complicated arrangement of these taxa, but an accepted taxonomic system has not yet been created. |
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| FIGURE 1. Cytophaga, a common soil microbe that efficiently breaks down cellulose. Image from http://genome.jgi-psf.org/finished_microbes/cythu/cythu.home.html | FIGURE 2. Beggiatoa, a filamentous bacterium that oxidizes hydrogen sulfide. Image from http://user.uni-frankfurt.de/~schauder/gradient/beggia06_bg.jpg | FIGURE 3. Thioploca, a name that means sulfur braid, is gigantic as bacteria go. Image from Maier (1980) |
FIGURE 4. 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. Note that it differs significantly from Figure 5, a tree generated by the All Species Living Tree Project.
FIGURE 5. A simplified summary tree for the Eubacteria adapted from the All Species Living Tree Project (Yarza et al. 2008 and 2010; Munoz et al. 2011). Note that the position of the taxa in this group (the clade that includes Bacteriodetes + Chlorobi + Fibrobacteres + Gemmatimodates) is more complicated relative to the different proteobacterial groups.
| FURTHER READING: DISCOVERY OF THE DOMAINS OF LIFE INTRODUCTION TO THE DOMAIN EUKARYA DESCRIPTION OF THE DOMAIN ARCHAEA |
| LITERATURE CITED Ahmad, A., J. P. Barry, and D. C. Nelson. 1999. Phylogenetic affinity of a wide, vacuolate, nitrate-accumulating Beggiatoa sp. from Monterey Canyon, California, with Thioploca spp. Applied and Environmental Microbiology. 65(1): 270-277. Barnes, R. S. K. 1984b. Kingdom Monera. IN: Barnes, R.S.K., ed. A synoptic classification of living organisms. Sinauer Associates. Sunderland, Mass. 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. 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. Holt, J. G., ed. 1989a. Other gram-negative bacteria, Cyanobacteria, Archaea. IN: Bergey’s manual of systematic bacteriology. Volume III. Williams and Wilkins. Baltimore, MD. 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. Maier, S. 1980. Growth of Thioploca ingrica in a mixed culture system. Ohio Acad. Sci. 80(1): 30-32. Margulis, L. and K. Schwartz. 1998. Five kingdoms, an illustrated guide to the phyla of life on earth. 3nd Edition. W. H. Freeman and Co. New York. Schmidt, T. M., B. Arieli, Y. Cohen, E. Padan, and W. R. Strohl. 1987. Sulfur metabolism in Beggiatoa alba. Journal of Bacterial. 169(12): 5466-5472. 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. |
| By Jack R. Holt. Last revised: 02/20/2013 |
