Spirochaeta

Classification

Domain Bacteria; Phylum Spirochetes; Class Spirochetes; Order Spirochaetales; Family Spirochaetaceae [Others may be used. Use NCBI link to find]

Species

NCBI: Taxonomy

Genus species

1. Spirochaeta africana
2. Spirochaeta alkalica
3. Spirochaeta americana
4. Spirochaeta asiatica
5. Spirochaeta aurantia
6. Spirochaeta bajacaliforniensis
7. Spirochaeta caldaria
8. Spirochaeta coccoides
9. Spirochaeta halophila
10. Spirochaeta isovalerica
11. Spirochaeta litoralis
12. Spirochaeta smaragdinae
13. Spirochaeta stenostrepta
14. Spirochaeta taiwanensis
15. Spirochaeta thermophila
16. Spirochaeta xylanolyticus
17. Spirochaeta zuelzerae
18. Spirochaeta sp.
19. Spirochaeta sp. AP13oN
20. Spirochaeta sp. ASpC-2
21. Spirochaeta sp. B
22. Spirochaeta sp. BHI80-158
23. Spirochaeta sp. Buddy
24. Spirochaeta sp. Grapes
25. Spirochaeta sp. HT
26. Spirochaeta sp. kf401
27. Spirochaeta sp. M-6
28. Spirochaeta sp. M6
29. Spirochaeta sp. MET-E
30. Spirochaeta sp. MWH-HuW24
31. Spirochaeta sp. MWH-HuW8
32. Spirochaeta sp. P
33. Spirochaeta sp. SIP1
34. Spirochaeta sp. TP422
35. Spirochaeta sp. TP561
36. Spirochaeta sp. TP663
37. Spirochaeta sp. TP664
38. unclassified Spirochaeta

   * Olavius loisae endosymbiont 4
   * Spirochaeta symbiont of Nautilus macromphalus (New Caledonia)
   * Spirochaeta symbiont of Nautilus pompilius (Philippines)
   * Spirochaeta symbiont of Nautilus pompilius (Vanuatu)
   * environmental samples

Description and Significance

The genus Spirochaeta represents a group of free-living, saccharolytic non-pathogenic, obligate or facultative anaerobic helical shaped bacteria. Isolated strains have been obtained from a variety of freshwaters and marine waters (Table 1). In addition, culture-independent studies revealed the presence of Spirochaeta species in other environments such as anaerobic bioreactors (Ariesyada et al., 2007), and the digestive tract of termites (Noda et al., 2003). A number of members of the genus Spirochaeta inhabit extreme environments with respect to temperature, salinity, and pressure (e.g., Hoover et al., 2003; Aksenova et al., 1992). These microorganisms may hence harbor enzymes with potential biotechnological applications.

Genome Structure

At present, a fully closed genome sequence of a member of Spirochaeta genus is not available.

Cell Structure, Metabolism and Life Cycle

The morphology and cellular structure of Spirochaeta spp. (and most other Spirochetes) is unique among prokaryotes. The cells are helical in shape and consist of an outer membrane, axial filaments (ultrastructurally similar to bacterial flagella), and a protoplasmic cylinder. The axial filaments reside under the outer membrane and are responsible for the unique mobility behavior of Spirochetes, a trait which has been linked to the pathogenicity of certain genera. Although the helical shape is typical for members of the Spirochetes phylum, a coccoid shaped Spirochaeta spp. was recently isolated from a termite gut by Droge et al. (2006).

The Spirochaeta genus contains a group a saccharolytic and dissipotrophic bacteria, responsible for decomposition of (poly)carbohydrates in many aquatic environments. All species of the Spirochaeta genus ferment carbohydrates with formation of acetate, ethanol, CO2, and H2 as major end products. In addition, Spirochaeta isovalerica ferments a number of amino-acids in addition to carbohydrates. All isolated Spirochaeta species utilize the Embden-Meyerhof pathway for glucose catabolization with formation of pyruvate.

Ecology and Pathogenesis

Species of the Spirochaeta genus are common inhabitants of a variety of aquatic environments, such as the water, sediments and muds of ponds, marshes, lakes, rivers and oceans. In these environments, Spirochaeta are capable of competing with other microorganisms for available nutrients by exhibiting various types of mobility behaviors. The unique mobility of Spirochetes is due to the helical shape of the cells and the polar positioning of the axial filaments.

References

[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.

Author

Page authored by Dieter Maurice Tourlousse and Godfrey Josef Torres, students of Prof. Jay Lennon at Michigan State University.