Thermus aquaticus*

From MicrobeWiki, the student-edited microbiology resource

A Microbial Biorealm page on the genus Thermus aquaticus*

Classification

Higher order taxa

Bacteria; Deinococcus-Thermus; Deinococci; Thermales; Thermaceae

Species

Thermus Aquaticus

T-aquaticus.gif.jpeg [5]

Description and significance

Thermus Aquaticus is a typical gram negative bacteria, meaning that its cell walls contain much less peptidoglycan than their gram positive cousins, and unlike gram positive bacteria, gram negative bacteria contain lipoproteins. Thermus Aquaticus appears as either a rod or short filaments, and the rod-shaped cells will tend to form either a rosette or a linear pattern [1]. When exposed to sunlight, Thermus can exhibit a yellow, pink, or red color due to pigments within the bacteria. Along with the coloration, Thermus Aquaticus can either have flagella or be immotile.

Thermus Aquaticus has proven to be quite a useful organism in the field of Biotechnology, as its enzyme Taq polymerase is harvested for use in polymerase chain reactions (PCR). The reason Taq polymerase is used in PCR, as opposed to other forms of the polymerase enzyme is because Thermus Aquaticus' form of the enzyme is well-suited for the repetitive heating involved in PCR and will not denature. Taq polymerase's resistance to heat is an adaptation to its environment, but is not the only reason it is the choice for use in PCR. Taq polymerase is also chosen because it is incredibly accurate, at 1x10^-4 to 2x10^-5 errors per base pair [2], and does not need to be completely pure to be effective [3]. These properties of Taq polymerase- it's heat resistance, accuracy, and potency- make PCR, and technologies that utilize PCR, such as DNA fingerprinting, enzyme production, and medical diagnoses possible.

Genome structure

Describe the size and content of the genome. How many chromosomes and plasmids? Circular or linear? Other interesting features? What is known about its sequence?

Cell structure, metabolism & life cycle

Provide a physical and biochemical description of the organism. What kind of organism is it, what does it look like, how is it built, what are its metabolic properties, how can it be identified, what is it's life cycle, &c. In other words, describe the organism from its perspective.

Ecology (including pathogenesis)

Thermus Aquaticus was first discovered in several hot springs in Yellowstone National Park, and to no surprise loves hot environments (those between 55 and 100 degrees Celsius) with a pH between 5 and 9, but is most able to flourish in temperatures between 70 to 75 degrees celsius and a pH of 7.5 to 8. Once discovered in the hot springs of Yellowstone, Thermus Aquaticus has since been found in marine thermal springs, low saline, solfataric springs, and thermally polluted water. Thermus Aquaticus is a chemotrophic organism, meaning it must acquire its energy from organic matter in the water, which sometimes means from photosynthetic cyanobacteria that share its habitat [4].

Interesting feature

Thermus aquaticus’ structure resembles that of other gram-negative bacteria. It has a three layered membrane composed of an inner plasma membrane, an intermediate and a rougher outer layer. Along the inner membrane usually lies a series of rod like structures that resemble individual cells, which are called rotund bodies. These cell like structures are the most unique characteristic of Thermus Aquaticus. The rest of its anatomy is just like other bacteria. However, there are no flagella or cilia present in Thermus Aquaticus, suggesting that this bacterium is immotile [6].

References

[1] Brock, Thomas D. and Mercedes R. Edwards. Journal of Bacteriology, Oct 1970, Vol 104. p 509-517. “Fine Structure of Thermus aquaticus, an Extreme Thermophile.”

[2] “Thermostable DNA Polymerases.” http://www.vivo.colostate.edu/hbooks/genetics/biotech/enzymes/hotpolys.html. 9/26/2007.

[3] “PCR (Polymerase Chain Reaction) – HIV: health and medical information about HIV and..” http://www.medicinenet.com/pcr_polymerase_chain_reaction/page2.htm. 9/25/2007.

[4] “Thermus aquatics.” Wikipedia. http://en.wikipedia.org/wiki/Thermus_aquaticus

[5] Townsend, Rich. "Terrestrial Life in Extreme Environments." http://zuserver2.star.ucl.ac.uk/~rhdt/diploma/lecture_6/. 2/18/2003.