Tropheryma whipplei

Classification

Higher order taxa

Cellular Organisms; Bacteria; Actinobacteria; Actinobacteria (class); Actinobacteridae; Actinomycetales; Micrococcineae; Cellulomonadaceae; Tropheryma; Tropheryma Whipplei (Bischoff).

Genus

Genus: Tropheryma Species: Whipplei

Description and significance

Tropheryma whipplei is a gram-postive bacterium. It was finally isolated in eukaryotic cells in the year 2000 and propagated in culture at thirty-seven degrees Celsius, but was believed to resist culturalization for a long time (Crapoulet). The isolation and culturalization has allowed more characterization, which include sequencing its genome. It has a 0.92-Mb genome, placing it in a high-G+C-content gram-positive bacterial group in comparison with others, such as Actinobacteria that have lower G+C contents (Crapoulet). Because it is a reduced genomic species, it does not have many genes regulating transcription (Crapoulet). This lack of regualtion is believed to be the case because inside the host cells the environment is apparently rather stable, and so T. whipplei does not need extensive regulation (Crapoulet). The way it infects its host and the nautral habitat from which T. whipplie arises is not very well understood as of yet, but because it lacks most regulatory components, it seems apparent that this enviornmental agent is capable of adapting to a wide range of stressful conditions, especially in relation to temperature (Crapoulet). Tropheryma whipplei is not affected by heat shock, but did modify its transcriptome following cold shock at a temperature of four degrees Celsius; this proves that although t lacks a lot of typical regulatory elements, it still has a highly adaptive response to thermal stresses that would be typical with its potential environmental origin being that of something at lower temperatures (something still being studied), thereby allowing it to live and adapt in cold conditions (Crapoulet).

Genome structure

With a 0.92 Mb genome (Crapoulet)

Ecology

Tropheryma whipplei is suspected to have an environmental origin (Crapoulet).

Pathology

Tropheryma whipplei is indeed a pathogen that causes disease in human beings. This poorly-known pathogen is responsible for causing Whipple disease (Crapoulet). This disease is destructive to many of the bodies systems. It causes intestinal malabsorption that leads to cachexia (Crapoulet). Cachexia is a physical wasting away of the body, and is often caused by disease such as advanced cancer, AIDS, and also in the case of Whipple disease. This wasting syndrome leads to a loss of weight, fat, and muscle, as in healthy people the body adjusts to lose its nutrients much more gradually during a state of starvation, but in the case of cachexia the body will not make any such necessary adjustments. Unfortunately, Whipple disease also effects not only the digestive system, but also the cardiac and central nervous systems as well (Crapuolet). If left untreated, this pathogen is fatal. Yet, even if antibiotic treatment is given, clinical relapses in the form of cerebral issues can ensue (Crapoulet).

References

1. Bischoff, Joe, et al. "Tropheryma whipplei." Taxonomy Browser. 10 Jan. 2007. NCBI. 1 June 2007

    <http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/
    wwwtax.cgi?mode=Info&id=2039&lvl=3&p=mapview&p=has_linkout&p=blast_url&p=genome_blast&lin=f&keep=1&sr
    chmode=1&unlock>. 

2. Crapoulet, Nicolas, et al. "Global Transcriptome Analysis of Tropheryma whipplei in Response to

    Temperature Stresses." Journal of Bacteriology 188.14 (July 2006): 28-39. American Society for
    Microbiology. Ed. Jack Kenney. 24 Apr. 2006. PubMed Central. 30 May 2007
    <http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1539978>. 

Edited by Sophia Gevorkian, student of Rachel Larsen and Kit Pogliano.