Borrelia garinii: Difference between revisions
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==Cell structure and metabolism== | ==Cell structure and metabolism== | ||
Like all the other spirochetes causing | Like all the other spirochetes causing Lyme disease, ''Borrelia garinii'' has a protoplasm protected by an inner and outer membrane. It also has flagella which are located between the inner and outer membrane. The flagellas of the ''Borrelia'' species are unique because the flagellas are not exposed to the host’s antibodies or tissues. The outer membrane proteins have many genes that are located on plasmids. This is very beneficial to the organism because it can make changes in those proteins; therefore, preventing foreign molecules from entering that could possibly be quite harmful. (Schaechter) The ''Borrelia'' species lack several metabolic enzymes. The glycolytic enzymes are present, but are missing a few in the pentose phosphate pathway. Such enzymes are the 6-phosphoglucono lactonase and transaldolase. Most enzymes for lipid metabolism are absent in spirochetes. Since spirochetes lack the ability to synthesize fatty acids, the NADPH requirement is limited. | ||
==Ecology== | ==Ecology== | ||
Revision as of 04:46, 5 June 2007
A Microbial Biorealm page on the genus Borrelia garinii
Classification
Higher order taxa
Bacteria; Spirochaetes; Spirochaetes (class); Spirochaetales; Spirochaetaceae; Borrelia; Borrelia burgdorferi group
Genus
Borrelia garinii
Description and significance
Borrelia garinii is a type of spirochete. Spirochetes are normally thin, approximately 0.1-0.5 micrometers by 5.0-20.0 micrometers. Borrelia garinii is generally characterized to have a spiral shape, to be motile, non-capsulated, and non-sporing. The Borrelia species can be anaerobic or microaerophilic. There are three types of Borrelia that can cause lyme disease: Borrelia burgdorferi, Borrelia afzelii, and Borrelia garinii. (Schaechter) In 1982, a man named Burgdofer identified spirochetes within the midsection of an adult deer tick, known as Ixodes dammini, renamed currently to Ixodes scapularis. Another researcher named Barbour, cultured spirochete in Kelly’s medium. Spirochetes have been cultured from blood and tissue samples of patients with erythema migrans, which is a rash associated with Lyme disease, and cerebral spinal fluid of patients with meningoencephalitis, which is a medical condition that resembles meningitis and encephalitis. Jennin and colleagues isolated Borrelia burgdoferi, a spirochete very similar to Borrelia garinii, from ticks and humans in 1984. Not much is known about the Borrelia species. In the future, hopefully new knowledge will be gained from analyzing the genome which will help identify new surface proteins to help possibly prevent, diagnose, and treat Lyme disease.
Genome structure
Borrelia species generally contain 930+/- 20 kbp. Borrelia garinii has one linear chromosome and codes for 869 genes.Borrelia garinii has a total of 969 genes. Out of these 969 genes, 931 are protein coding genes. Borrelia garinii has one linear chromosome and codes for 869 genes. Like other Borrelia, it also contains one copy each of different types of linear and circular plasmids. (Saer)Linear plasmids are very rare and have only been detected in two other eubacteria. One being Streptomyces lividands and Argobacterium turnefaciens. The ends of the Borrelia chromosome and linear plasmids are covalently closed loops. The linear plasmids are approximately 10kb-180kb, while the circular plasmids are approximately 8-40kb. (Saier) The G-C content of Borrelia species are estimated to be approximately thirty percent of their genome. Borrelia garinii has a G-C content of 28.12%. Some unique properties were found during experiments with Borrelia burgdorferi, which could apply to Borrelia garinii. Borrelia burgodorferi lacks invasion genes, global regulatory systems, toxins, and 2-component signal transduction that can be traced back to a common ancestor. A second unique property of Borrelia burgodorferi is that there is a large amount of duplicated lipoproteins. So far, no functions for the duplicated lipoproteins have been found. The small genome of the Borrelia species suggests that it highly depends on some of the host’s cellular machinery to replicate.
Cell structure and metabolism
Like all the other spirochetes causing Lyme disease, Borrelia garinii has a protoplasm protected by an inner and outer membrane. It also has flagella which are located between the inner and outer membrane. The flagellas of the Borrelia species are unique because the flagellas are not exposed to the host’s antibodies or tissues. The outer membrane proteins have many genes that are located on plasmids. This is very beneficial to the organism because it can make changes in those proteins; therefore, preventing foreign molecules from entering that could possibly be quite harmful. (Schaechter) The Borrelia species lack several metabolic enzymes. The glycolytic enzymes are present, but are missing a few in the pentose phosphate pathway. Such enzymes are the 6-phosphoglucono lactonase and transaldolase. Most enzymes for lipid metabolism are absent in spirochetes. Since spirochetes lack the ability to synthesize fatty acids, the NADPH requirement is limited.
Ecology
Describe any interactions with other organisms (included eukaryotes), contributions to the environment, effect on environment, etc.
Pathology
Like many other Borrelia species, Borrelia garinni rely on arthropods for transmission. A tick from the genus 'Ornithodoros, generally carries Borrelia garinni within it's gut and it then infects host cells through a tick bite. While in the gastro-intestinal section of the tick, Borrelia garinii and other spirochetes do not replicate because of their attachment to epithelial cells. Once the spirochetes make contact with high heat and mammalian blood, the expression of the outer surface proteins change drastically. Borrelia garinii is no longer dormant and begins to spread through the wall of the gut and through the entire tick. The spirochetes infect mammalian cells through the salivary glands of the ticks.Borrelia burgdorferi, a spirochete very similar to Borrelia garinni, binds to human platelets and endothelial cells through beta II b beta 3 and beta v beta 3. Once Borrelia burgdorferi binds to human platelets and endothelial cells, it is transported to the entire body through the blood system. In areas where blood flow is slow, Borrelia species' movements are generally stopped. This occurs to establish infection to tissues nearby.
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
1. Ed. Saier, Milton H., and Jorge Garcia-Lara. The Spriochetes: Molecular and Cellular Biology. United Kingdom: Norfolk, 2001
2. Schaechter, Moselia, N. Cary Engleberg, Berry I. Eisenstein, Gerald Medoff. Mechanisms of Microbial Disease: third ed.. 1998
4. Baranton, G., Postic, D., Saint Girons, I., Boerlin, P., Piffaretti, J.C., Assous, M., and Grimont, P.A. "Delineation of Borrelia burgdorferi sensu stricto, Borrelia garinii sp. nov., and group VS461 associated with Lyme borreliosis." Int. J. Syst. Bacteriol. (1992) 42:378-383.
5. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi db=genome&cmd=Retrieve&dopt=Overview&list_uids=495
Edited by Kimberly Tong, student of Rachel Larsen and Kit Pogliano
