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Genus larsen
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A Microbial Biorealm page on the genus Genus larsen


Contents [hide]
==Classification==
1 Classification  
===Higher order taxa===
1.1 Higher order taxa  
Domain:Bacteria,
1.2 Species
Phylum: Proteobacteria, Class: Rickettsiales, Order: Rickettsiales, Family: Rickettsiaceae
2 Description and significance
 
3 Genome structure
===Species===
4 Cell structure and metabolism
NCBI: Taxonomy
5 Ecology
6 Pathology
7 Application to Biotechnology
8 Current Research
9 References
   
   


Classification
''Rickettsia typhi''
Domain: Bacteria
 
Phylum:Proteobacteria
==Description and significance==
Class: Rickettsiales
''Rickettsia typhi'' is a small Gram-negative rod bacteria. Therefore, it has an outer membrane and a thin murein layer. Murein is a strong polymer found in the cell walls of prokaryotes. Lipopolysaccharides which are unique to bacteria can be found on it’s outer membrane as well(6). ''Rickettsia typhi'' is the cause of murine typhus. A terrible disease, this endemic typhus or murine typhus is much milder than the epidemic typhus caused by ''R. prowazeki''. Infection causes headache, fever, and can lead to multisystem disease, including infection of the brain, lung, liver, kidney and heart. Humans become infected when the flea or tick deposits its feces on the human's skin(1).
Order
Family: Rickettsiaceae


Species
[[Image:rick2-an.jpeg|thumb|1000px|American Society for Microbiology-MicrobeLibrary.org: Rickettsia, Obligately Intracellular Bacteria, Pathogenic for Humans I [ http://www.microbelibrary.org/images/Walker/images/rick2-an.jpg ].]]
NCBI: Taxonomy


Rickettsia, typhi
==Genome structure==
The complete genome sequence of ''R. typhi'' is 1,111,496 base pairs. There were 877 genes, 838 encode proteins and 24 were unique to ''R. typhi''(5). The Guanine + Cytosine(G+C) content in its DNA is roughly 29-30% of it's DNA. ''R. typhi's'' genome size is 1080 Mdaltons and it has the typical prokaryote circular chromosome(3). Currently, no plasmids have been found in this microbe.


Description and significance
==Cell structure and metabolism==
Describe the appearance, habitat, etc. of the organism, and why it is important enough to have its genome sequenced. Describe how and where it was isolated. Include a picture or two (with sources) if you can find them.  
Rickettsiae thrive in environments with a high concentration of potassium an a low concentration of glucose(sugar), usually this is the cytosol of eukaryotic cells. Cell membrane transport systems are used to acquire molecules such as ATP(energy) and amino acids from the host(3). This is one of many ways this microbe exploits its host. Its inability to maintain concentrations of essential nutrients like ATP, make ''R. typhi'' relatively non-motile. This non-motility allows for accumulation of the microbe in the host cell, which causes the cell to lyse/burst(2). However, they also have an independent metabolism where they can produce their own ATP and proteins. Rickettsiae enter the cells by phagocytosis, a process where a microorganism enters a cell through it's membrane. Later they escape and replicate in the cytoplasm of other cells.
==Ecology==
Humans are affected by this because ticks/fleas can carry this bacteria, spreading typhus. Although typhus can be found worldwide, it is mostly present in warm coastal areas. Typhus is uncommon in the United States. It is usually seen in areas where hygiene is poor. In the past, spread of typhus created many sick people, and determined the outcome of some wars.


Genome structure
==Pathology==
Describe the size and content of the genome. How many chromosomes? Circular or linear? Other interesting features? What is known about its sequence? Does it have any plasmids? Are they important to the organism's lifestyle?
''Rickettsia typhi'' can be transmitted to the host by the bite of an infected arthropod(tick or flea) or through the feces of the carrier, causing typhus. In people, typhus causes fever, chills, headache, and general pain. In the endothelium tissue is where the microbe divides and transmits its infection(4). The microbe accumulates then the host cell bursts releasing many rickettsia. Destruction of the endothelial cell causes damaged tissue, organs, and loss of blood. Sometimes a rash is found on the body. The disease is diagnosed through blood testing. Anti-biotics are made to enter the host cells and aid in decreasing the effects or ''R. typhi''. Some medications made are doxycycline, tetracycline and chloramphenicol. Prevention of the disease is through rodent and flea control.
==Application to Biotechnology==
Murine typhus is caused by ''R. typhi'', however no other useful compounds or enzymes have been found from this microbe that are useful to biotechnology. Its ability to be acquired via aerosol, its painful sypmtoms, and its rate of infection make rickettsiae a potential bioweapon and bioterror agent.
==Current Research==
Rickettsiae cannot be cultivated on an artificial medium in the lab. The organism must be grown in other ways such as in animals or cell cultures. Currently, different oraganisms and different environments are being tested to find different ways to cultivate this microbe. Also, this microbe affects the pesticide industry, for developments of insecticides and rat control are being made to decrease the probability of typhus occurring.


Cell structure and metabolism
==References==
Describe any interesting features and/or cell structures; how it gains energy; what important molecules it produces.  
(1)Schaechter, Moselio, and Medoff, Gerald, and Eisenstein, Barry. ''Mechanisms of Microbial Disease, Second Edition''. Baltimore, Maryland: Williams & Wilkins, 1993


Ecology
(2)Schaechter, Moselio, and Engleberg, Cary, and Medoff, Gerald, and Eisenstein, Barry. ''Mechanisms of Microbial Disease, Third Edition''. Baltimore, Maryland: Williams & Wilkins, 1998
Describe any interactions with other organisms (included eukaryotes), contributions to the environment, effect on environment, etc.  


Pathology
(3)Walker, David. ''Biology of Rickettsial Diseases''. Galveston, Texas: CRC Press, 1988
How does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.


Application to Biotechnology
(4)Goodman, Jesse, and Dennis, David, and Sonenshine, Daniel. ''Tick-Borne Diseases of Humans''. Washington, D.C.: ASM Press, 2005
Does this organism produce any useful compounds or enzymes? What are they and how are they used?


Current Research
(5)Complete Genome Sequence of Rickettsia typhi and Comparison with Sequences of Other Rickettsiae. 6 April 2007 <http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=516817>
Enter summaries of the most recent research here--at least three required


References
(6)RICKETTSIA, CHLAMYDIA, MYCOPLASMA. 31 April 2007 <http://www.kcom.edu/faculty/chamberlain/Website/Lects/RICKETT.HTM>
[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.  


Edited by student of Rachel Larsen and Kit Pogliano  
Edited by Omar Mendoza student of Rachel Larsen and Kit Pogliano  


Retrieved from "http://microbewiki.kenyon.edu/index.php/Genus_larsen"
Retrieved from "http://microbewiki.kenyon.edu/index.php/Genus_larsen"
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This page was last modified 20:43, 30 April 2007. This page has been accessed 1,343 times. Privacy policy About MicrobeWiki Disclaimers
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Latest revision as of 20:15, 29 April 2011

This is a curated page. Report corrections to Microbewiki.

A Microbial Biorealm page on the genus Rickettsia typhi

Classification

Higher order taxa

Domain:Bacteria, Phylum: Proteobacteria, Class: Rickettsiales, Order: Rickettsiales, Family: Rickettsiaceae

Species

NCBI: Taxonomy


Rickettsia typhi

Description and significance

Rickettsia typhi is a small Gram-negative rod bacteria. Therefore, it has an outer membrane and a thin murein layer. Murein is a strong polymer found in the cell walls of prokaryotes. Lipopolysaccharides which are unique to bacteria can be found on it’s outer membrane as well(6). Rickettsia typhi is the cause of murine typhus. A terrible disease, this endemic typhus or murine typhus is much milder than the epidemic typhus caused by R. prowazeki. Infection causes headache, fever, and can lead to multisystem disease, including infection of the brain, lung, liver, kidney and heart. Humans become infected when the flea or tick deposits its feces on the human's skin(1).

American Society for Microbiology-MicrobeLibrary.org: Rickettsia, Obligately Intracellular Bacteria, Pathogenic for Humans I [ http://www.microbelibrary.org/images/Walker/images/rick2-an.jpg ].

Genome structure

The complete genome sequence of R. typhi is 1,111,496 base pairs. There were 877 genes, 838 encode proteins and 24 were unique to R. typhi(5). The Guanine + Cytosine(G+C) content in its DNA is roughly 29-30% of it's DNA. R. typhi's genome size is 1080 Mdaltons and it has the typical prokaryote circular chromosome(3). Currently, no plasmids have been found in this microbe.

Cell structure and metabolism

Rickettsiae thrive in environments with a high concentration of potassium an a low concentration of glucose(sugar), usually this is the cytosol of eukaryotic cells. Cell membrane transport systems are used to acquire molecules such as ATP(energy) and amino acids from the host(3). This is one of many ways this microbe exploits its host. Its inability to maintain concentrations of essential nutrients like ATP, make R. typhi relatively non-motile. This non-motility allows for accumulation of the microbe in the host cell, which causes the cell to lyse/burst(2). However, they also have an independent metabolism where they can produce their own ATP and proteins. Rickettsiae enter the cells by phagocytosis, a process where a microorganism enters a cell through it's membrane. Later they escape and replicate in the cytoplasm of other cells.

Ecology

Humans are affected by this because ticks/fleas can carry this bacteria, spreading typhus. Although typhus can be found worldwide, it is mostly present in warm coastal areas. Typhus is uncommon in the United States. It is usually seen in areas where hygiene is poor. In the past, spread of typhus created many sick people, and determined the outcome of some wars.

Pathology

Rickettsia typhi can be transmitted to the host by the bite of an infected arthropod(tick or flea) or through the feces of the carrier, causing typhus. In people, typhus causes fever, chills, headache, and general pain. In the endothelium tissue is where the microbe divides and transmits its infection(4). The microbe accumulates then the host cell bursts releasing many rickettsia. Destruction of the endothelial cell causes damaged tissue, organs, and loss of blood. Sometimes a rash is found on the body. The disease is diagnosed through blood testing. Anti-biotics are made to enter the host cells and aid in decreasing the effects or R. typhi. Some medications made are doxycycline, tetracycline and chloramphenicol. Prevention of the disease is through rodent and flea control.

Application to Biotechnology

Murine typhus is caused by R. typhi, however no other useful compounds or enzymes have been found from this microbe that are useful to biotechnology. Its ability to be acquired via aerosol, its painful sypmtoms, and its rate of infection make rickettsiae a potential bioweapon and bioterror agent.

Current Research

Rickettsiae cannot be cultivated on an artificial medium in the lab. The organism must be grown in other ways such as in animals or cell cultures. Currently, different oraganisms and different environments are being tested to find different ways to cultivate this microbe. Also, this microbe affects the pesticide industry, for developments of insecticides and rat control are being made to decrease the probability of typhus occurring.

References

(1)Schaechter, Moselio, and Medoff, Gerald, and Eisenstein, Barry. Mechanisms of Microbial Disease, Second Edition. Baltimore, Maryland: Williams & Wilkins, 1993

(2)Schaechter, Moselio, and Engleberg, Cary, and Medoff, Gerald, and Eisenstein, Barry. Mechanisms of Microbial Disease, Third Edition. Baltimore, Maryland: Williams & Wilkins, 1998

(3)Walker, David. Biology of Rickettsial Diseases. Galveston, Texas: CRC Press, 1988

(4)Goodman, Jesse, and Dennis, David, and Sonenshine, Daniel. Tick-Borne Diseases of Humans. Washington, D.C.: ASM Press, 2005

(5)Complete Genome Sequence of Rickettsia typhi and Comparison with Sequences of Other Rickettsiae. 6 April 2007 <http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=516817>

(6)RICKETTSIA, CHLAMYDIA, MYCOPLASMA. 31 April 2007 <http://www.kcom.edu/faculty/chamberlain/Website/Lects/RICKETT.HTM>

Edited by Omar Mendoza student of Rachel Larsen and Kit Pogliano

Retrieved from "http://microbewiki.kenyon.edu/index.php/Genus_larsen"

KMG