<P> When studies of biological organisms in hot springs began in the 1960s, scientists thought that the life of thermophilic bacteria could not be sustained in temperatures above about 55 ° C (131 ° F). Soon, however, it was discovered that many bacteria in different springs not only survived, but also thrived in higher temperatures . In 1969, Thomas D. Brock and Hudson Freeze of Indiana University reported a new species of thermophilic bacteria which they named Thermus aquaticus . The bacterium was first discovered in the Lower Geyser Basin of Yellowstone National Park, near the major Great Fountain Geyser and White Dome Geyser, and has since been found in similar thermal habitats around the world . </P> <P> It thrives at 70 ° C (158 ° F), but can survive at temperatures of 50 ° C to 80 ° C (122 ° F to 176 ° F). This bacterium is a chemotroph--it performs chemosynthesis to obtain food . However, since its range of temperature overlaps somewhat with that of the photosynthetic cyanobacteria that share its ideal environment, it is sometimes found living jointly with its neighbors, obtaining energy for growth from their photosynthesis . </P> <P> Thermus aquaticus is generally of cylindrical shape with a diameter of 0.5 μm to 0.8 μm . The shorter rod shape has a length of 5 μm to 10 μm . The longer filament shape has a length that varies greatly and in some cases exceeds 200 μm . The rod - shaped bacteria have a tendency to aggregate . Associations of several individuals can lead to the formation of spherical bodies 10 μm to 20 μm in diameter, also called rotund bodies . </P> <P> T. aquaticus has become famous as a source of thermostable enzymes, particularly the Taq DNA polymerase, as described below . </P>

Dna polymerase from thermus aquaticus is used in pcr because