Species: Treponema primitia
The name "primitia", meaning "first fruits" in Latin, refers to its discovery as the first Spirochete isolated from termite guts. (7)
Description and Significance
T. primitia is a microorganism that lives in the hindgut of the termite Zootermopsis angusticolis and synthesizes acetate, the primary source of energy of their insect host, from the H2 and CO2 generated by protozoa during the fermentation of wood polysaccharides. (3) T. primitia is a motile gram-negative microorganism which its motion can best be described as a rigid helix with no noticeable gyrations or deformations. (5) T. primitia relies on a chemosensory system to help guide it to favorable environmental conditions. (6) Methyl-accepting chemotaxis proteins (MCPs) are transmembrane chemoreceptors that T. primitia depends on to complete the process of chemotaxis. (6) Similar to Escherichia coli, T. primitia exhibits a chemoreceptor array system that is polar. (6)
T. primitia is 0.2 μm in diameter and 3 to 7 μm long. (7)
The genome of T. primitia has 3,683 total genes with 3,523 protein encoding genes across a genome of 4.06 megabase pairs on one chromosome. The GC content is roughly 50.8%. (1)
Within the Genus
The genus of Treponema has a lot of variety contained within it. Included in this genus are both symbionts (like Treponema primitia) and pathogens. One pathogen is T. pallidum which is divided into subspecies pallidum, pertenue, and endemicum which cause venereal syphilis, yaws, and endemic syphilis respectively. (4)
Primitia is an acetogen that primarily fixes CO2 with H2 in the net reaction:
- 4 H2 + 2 CO2 → CH3COOH + 2 H2O
though it is also able to utilize different carbon sources too (2). It is thought that T. primitia gets a large portion of its H2 from an obligate anaerobe. (3) Acetate produced by microbes is an important source of energy and carbon for termites. (7) Termites also benefit from microbe-mediated dinitrogen fixation which is an important component for termite development and growth. (7)
T. primitia is an acetogen that is involved in a mutualistic relationship with both Treponema azotonutricium and the termite in which it resides in. (8) T. azotonutricium fixes nitrogen and produces H2 as a fermentation product. (8) This fermentation product is then taken up by T. primitia which allows it to produce acetate and amino acids by way of the reduction of CO2. (8)
(1) National Center for Biotechnology Information. "Treponema primitia". LINK: http://www.ncbi.nlm.nih.gov/genome/1762
(2) Leadbetter, J., Schmidt, T., Graber, J., Breznak, J. "Acetogenesis from H-2 plus CO2 by spirochetes from termite guts." Science , 1999, DOI:10.1126/science.283.5402.686
(3) Murphy, G. E., Matson, E. G., Leadbetter, J. R., Berg, H. C., Jensen, G. J. "Novel ultrastructures of treponema primitia and their implications for motility." Molecular Microbiology, 2008, 67(6), 1184–1195, DOI: 10.1111/j.1365-2958.2008.06120.x.
(4) Radolf, J. "Chapter 36: Treponema". Medical Microbiology, 4th edition. Galveston, Texas: University of Texas Medical Branch at Galveston, 1996, ISBN-10: 0-9631172-1-1.
(5) Wolgemuth, C., Goldstein, S. F., & Charon, N. W. "Electron cryotomography reveals novel structures of a recently cultured termite gut spirochete." Molecular Microbiology, 2008, 67(6), 1181–1183.DOI: 10.1111/j.1365-2958.2008.06111.x
(6) Briegel, A., Ortega, D.R., Tocheva, E.I., Wuichet, K., Li, Z., Chen, S., Müller, A., Iancu, C.V., Murphy, G.E., Dobro, M.J., Zhulin, I.B., Jensen, G.J., “Universal architecture of bacterial chemoreceptor arrays.” PANS, 2009, 106(40), 17181-17186, DOI: 10.1073/pnas.0905181106
(7) Graber, J. R., Leadbetter, J. R., & Breznak, J. A. "Description of treponema azotonutricium sp. nov. and treponema primitia sp. nov., the first spirochetes isolated from termite guts." Applied Environmental Microbiology, 2004, 70(3), 1315-1320. DOI: 10.1128/AEM.70.3.1315-1320.2004
(8) Rosenthal, A. Z., Matson, E. G., Leadbetter, J. R., & Eldar, A. "Rna-seq reveals cooperative metabolic interactions between two termite-gut spirochete species in co-culture." The ISME Journal, 2011, 5, 1133–1142.