Thermus aquaticus
Introduction
Thermus aquaticus is a species of bacteria that is notable for its ability to survive in high-temperature environments. This thermophilic bacterium was first discovered in the hot springs of Yellowstone National Park, USA, and has since been found in various other hot environments around the world. The organism's ability to withstand high temperatures has made it a valuable tool in the field of molecular biology, particularly in the technique of polymerase chain reaction (PCR), a method used to amplify DNA sequences.
Discovery
Thermus aquaticus was first discovered in 1969 by Thomas D. Brock and Hudson Freeze while they were conducting research on the microbial life in the hot springs of Yellowstone National Park. The bacterium was found in the Mushroom Spring in the Lower Geyser Basin, which has an average temperature of 70 degrees Celsius. The discovery of T. aquaticus marked a significant breakthrough in understanding the range of conditions in which life can exist.
Classification
Thermus aquaticus is a member of the Deinococcus-Thermus phylum, a group of bacteria known for their ability to withstand extreme conditions. It is classified under the family Thermaceae, which includes other thermophilic bacteria. The genus Thermus consists of several species, with T. aquaticus being one of the most well-known due to its use in molecular biology.
Morphology
T. aquaticus is a rod-shaped bacterium, typically measuring 0.5 to 0.8 micrometers in diameter and 5 to 10 micrometers in length. The cells often appear in clusters, forming irregularly shaped aggregates. The cell wall of T. aquaticus is composed of a unique type of peptidoglycan, which contributes to its ability to withstand high temperatures.
Physiology
T. aquaticus is capable of surviving in temperatures ranging from 50 to 80 degrees Celsius, with an optimum growth temperature of around 70 degrees Celsius. It is an obligate aerobe, meaning it requires oxygen to survive. The bacterium is also capable of using a variety of organic compounds as a source of carbon and energy, including sugars, amino acids, and small organic acids.
Ecological Role
T. aquaticus plays a significant role in the ecology of hot springs. It contributes to the decomposition of organic matter, thereby helping to recycle nutrients in these environments. Furthermore, it forms part of the microbial mats that can be seen in many hot springs, which are complex communities of different microorganisms living together.
Significance in Molecular Biology
The most significant contribution of T. aquaticus to science has been in the field of molecular biology, specifically in the development of the polymerase chain reaction (PCR) technique. In 1983, Kary Mullis developed the PCR method, which allows for the amplification of specific DNA sequences. The key to this technique is the use of a heat-stable DNA polymerase enzyme, which can withstand the high temperatures required for the denaturation of DNA. T. aquaticus produces a DNA polymerase known as Taq polymerase, which has the necessary heat stability. This has made PCR a routine procedure in molecular biology labs worldwide.