by Piter Kehoma Boll
It’s time for us to start to look at the tiny little creatures living with us in this world. We haven’t featured any bacterium yet, so here comes the first one, the magnificent Taq!
Taq stands for Thermus aquaticus, the bacterium’s scientific name. It was initially discovered in hot springs of the Yellowstone National Park, but certainly no one could guess how it would impact science as a whole.
Usually with a small rod shape less than 1 µm in diameter and up to 10 µm in length, Taq can also reach more than 200 µm in length when acquiring a filament shape. Living in hot springs all around the world, it thrives at about 70°C. It produces its own food via chemosynthesis by oxydizing inorganic elements in the environment, but it can also associate with some cyanobacteria living in the same habitat to obtain food from their photosynthesis.
But what impact did it have in science? Well, because it lives in such high temperatures, Taq’s proteins need higher temperatures to denature, so they are useful to perform biochemical processes in high temperatures, such as in DNA amplification.
PCR (polymerase chain reaction) is a process used for amplifying short segments of an organism’s DNA. It needs to be performed in high temperatures in order to denaturate the DNA chain so that the primers can align. Primers are very short modified DNA fragments that determinate the beginning and the end of the segments that one wants to amplify. Amplifying a DNA segment means producing a large amount of copies of that segment. The problem in earlier PCRs was that the high temperatures needed to denaturate the DNA also denature the enzyme that produces the copies, called DNA polymerase. As a result, there was a need to add enzyme after every cycle of thermal denaturation. The DNA polymerase of Taq, called Taq polymerase, can resist the high temperatures of denaturation, so that it needs to be added only once.
Thanks to Taq polymerase, DNA amplification has become a much more efficient process, accelerating researches in molecular biology.
Sometimes revolution beginns with the tiniest things.
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Brock, T. D. 1997. The value of basic research: discovery of Thermus aquaticus and other extreme thermophiles. Genetics, 146(4): 1207-1210.
Wikipedia. Thermus aquaticus. Available at: <https://en.wikipedia.org/wiki/Thermus_aquaticus>. Access on January 21, 2016.
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