Mycobacterium tuberculosis

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Scientific classification
Kingdom: Bacteria Phylum: Actinobacteria Class: Actinomycetales Order: Corynebacterineae Family: Mycobacteriaceae Genus: Mycobacterium Species: tuberculosis
Binomial name
Mycobacterium tuberculosis

Description and significance

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.

Genome structure

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?

Cell structure and metabolism

(Temporary General Outline)

- Obligate Aerobe: Explains why it infects the upper lobes of the lungs

- Slow rate of growth compared to other bacteria (about 15-20 hours)

- Non-motile rod shaped

- Size: ~2-4 um in length and 0.2-0.5 um in width

- Acid-fast staining is used (specifically Ziehl-Neelsan Stain)

- Cell wall: peptidoglycan but note 60% lipid (Mycolic Acid, Cord Factor, Wax-D) High lipid percentage results in a lot of interesting properties: (impermeability to stain; different kinds of resistances (antibiotics, osmotic lysis, acidic and alkaline compounds, oxidation).

Ecology

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

Pathology

(Temporary General Outline)

- Major cause of tuberculosis (can link to tuberculosis page later)

- Binding to mannose receptors (for entry into cell)

- Ability to prevent lysosome from fusing with phagosome, as a result prevents the destruction of the bacteria.

- Slow generation may actually help the bacteria from being detected by the immune system.

- Cell wall construction is 60% lipid. Lot of different types of resistances.

- Antigen 85: binds to fibronectin and may help in protecting the bacteria from the immune system.

- Interference with oxygen intermediates

Application to Biotechnology

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

Current Research

Summaries to come

Pubmed article about BCG vaccine

Pubmed article about the discovery of lipolytic enzymes which may be involved with virulence

Article concering multi-drug resistant mycobacterium tuberculosis

References

1. www.textbookofbacteriology.net

2. Honaker RW, Stewart A, Schittone S, Izzo A, Klein MR, Voskuil MI "BCG vaccine strains lack narK2 and narX induction and exhibit altered phenotypes during dormancy." Infect Immun. 2008 Mar 24

3. Côtes K, Bakala N'goma JC, Dhouib R, Douchet I, Maurin D, Carrière F, Canaan S. "Lipolytic enzymes in Mycobacterium tuberculosis." Appl Microbiol Biotechnol. 2008 Apr;78(5):741-749. Epub 2008 Feb 29.

4. Raphael C. Y. Chan, Mamie Hui, Edward W. C. Chan, T. K. Au, Miu L. Chin, Chun K. Yip1, Carrie K. W. AuYeang, Christina Y. L. Yeung1, Kai M. Kam, Peter C. W. Yip and Augustine F. B. Cheng. "Genetic and phenotypic characterization of drug-resistant Mycobacterium tuberculosis isolates in Hong Kong" Journal of Antimicrobial Chemotherapy 2007 59(5):866-873.