Treponema pallidum

A Microbial Biorealm page on the genus Treponema pallidum

Classification

Higher order taxa

Eubacteria; Spirochaetes; Spirochaetes; Spirochaetales; Spirochaetaceae; Treponema

Species

Treponema pallidum, T. pertenue, T. endemicum

NCBI: Taxonomy

Description and significance

Treponema pallidum is a spiral shaped flexible bacteria about 0.1-0.18 µm in diameter and 6-20 µm long which is the disease causing agent of syphilis. Syphilis is a sexually transmitted disease which was first discovered in Europe near the end of the fifteenth century. The causative agent, T. pallidum, was not identified until 1905. Although treatments are available, syphilis remains a health problem throughout the world. The virulent strain of T. pallidum was first isolated 1912 from a neurosyphilitic patient.

Genome structure

Treponema pallidum has a double stranded circular DNA genome with a lenght of 1,138,011 nt. It contains 1095 genes which encode 1036 proteins. It contains 51 structural RNAs and no plasmids. The sequence of T. pallidum was completed in 2001. DNA replication, transcription, translation, and repair mechanisms are intact.

Cell structure and metabolism

Treponema pallidum is a gram negative bacteria. It is a spirochete meaning that is is helical in shape. As with all gram negative bacteria, it has an inner and outer membrane which contains within them a thin layer of peptidoglycan which provides structural stability. T. pallidum lacks lipopolysaccharide, the endotoxin found in the outer membranes of many gram-negative bacteria. The pathogenic strain of T. pallidum have a capsule-like outer coat absent in the nonpathogenic strain. The most interesting aspect of T. pallidum sturcture is that within the periplasmic space are endoflagella which are responsible for T. pallidum's motility.

Treponema pallidum is small with a small genome, therefore it is intuitive that it has a relatively simple metabolism. T. pallidum is able to carry out glycolysis but lacks the enzymes require for the Krebs cycle and also lacks an electron transport chain. T. pallidum is able to perform the interconversion of amino acids and fatty acids but is deficient in amino acid and fatty acid synthesis pathways. After analysis of the T. pallidum genome it is thought that the organism lacks the pathways for energy production via alternative carbon sources.

Ecology

Describe any interactions with other organisms (included eukaryotes), contributions to the environment, effect on environment, etc.

Pathology

How does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.

Application to Biotechnology

Does this organism produce any useful compounds or enzymes? What are they and how are they used?

Current Research

Enter summaries of the most recent research here--at least three required

References

Rebecca E. LaFond and Sheila A. Lukehart "Biological Basis for Syphilis" Departments of Pathobiology, Medicine, University of Washington, Seattle, Washington 2006 American Society for Microbiology

Treponema pallidum subsp. pallidum str. Nichols (Project ID: 5) at US DOE Joint Genome Institute http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=5

Fraser CM,Norris SJ,Weinstock GM,White O, Sutton GG,Dodson R,Gwinn M,Hickey EK,Clayton R,Ketchum KA,Sodergren E,Hardham JM,McLeod MP,Salzberg S,Peterson J,Khalak H,Richardson D,Howell JK,Chidambaram M,Utterback T,McDonald L,Artiach P,Bowman C,Cotton MD,Fujii C,Garland S,Hatch B,Horst K, Roberts K,Sandusky M,Weidman J,Smith HO,Venter JC. "Complete genome sequence of Treponema pallidum, the syphilis spirochete" 1998 Institute for Genomic Research, Rockville, MD 20850, USA.

Greene SR, Stamm LV, Hardham JM, Young NR, Frye JG "Identification, sequences, and expression of Treponema pallidum chemotaxis genes" 1997 Department of Epidemiology, School of Public Health, University of North Carolina, Chapel Hill

Weinstock GM, Hardham JM, McLeod MP, Sodergren EJ, Norris SJ "The genome of Treponema pallidum: new light on the agent of syphilis" 1998 Department of Microbiology and Molecular Genetics, University of Texas Medical School, Houston

Edited by Jasmin Eshragh, student of Rachel Larsen at UCSD.