Thermus aquaticus

Lore & Background

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. Soon, however, it was discovered that many bacteria in different springs not only survived, but also thrived in higher temperatures. Brock and Hudson Freeze of Indiana University reported a new species of thermophilic bacteria which they named Thermus aquaticus. The bacterium was first isolated from Mushroom Spring in the Lower Geyser Basin of Yellowstone National Park, which is near the major Great Fountain Geyser and White Dome Geyser, and has since been found in similar thermal habitats around the world. T. aquaticus shows best growth at 65–70 °C, but can survive at temperatures of 50–80 °C. It primarily scavenges for protein from its environment, as evidenced by the large number of extracellular and intracellular proteases and peptidases. This bacterium is a chemotroph—it performs chemosynthesis to obtain food. However, since its range of temperature overlaps somewhat with that of photosynthetic cyanobacteria, it is sometimes found living jointly with its neighbors, obtaining energy for growth from their photosynthesis. The genetic material of T. aquaticus consists of one chromosome and four plasmids, and its complete genome sequencing revealed that it contains two full and two partial prophages, as well as numerous CRISPR loci.

Reader's Guide

PCR facilitated advancements in medical diagnostics, genetics, and other fields. The heat-resistant Taq DNA polymerase, isolated from T. aquaticus, eliminated the need to add E. coli polymerase enzymes after every cycle of thermal denaturation of the DNA. The commercial use of enzymes from T. aquaticus has not been without controversy. After Brock's studies, samples of the organism were deposited in the American Type Culture Collection, a public repository. As the commercial potential of Taq polymerase became apparent in the 1990s, the National Park Service labeled its use as the 'Great Taq Rip-off'. Researchers working in National Parks are now required to sign 'benefits sharing' agreements that would send a portion of later profits back to the Park Service. Overall, Brock's initial discovery in Yellowstone's hot springs paved the way for significant scientific breakthroughs, demonstrating the importance of basic research in driving innovation and technological advancements.

Did You Know?

• The bacterium can survive at temperatures of 50–80 °C and shows best growth at 65–70 °C.
• The National Park Service labeled the commercial use of Taq polymerase without compensation as the 'Great Taq Rip-off'.