When bacteriologist Thomas Brock started probing the hot springs in Yellowstone National Park in the 1960s, he was not looking to overthrow a ground rule of biology.
Instead, the University of Wisconsin-Madison professor was looking to study bacteria in a simplified, real-world environment.
These hot springs at Yellowstone owe their vibrant colors to heat-loving microorganisms. Courtesy of Thomas D. Brock.
Then -- as now -- precious little was known about how bacteria live their lives -- except for those that cause disease.
As Brock sampled his way up a hot stream in Yellowstone, he approached the hot spring supplying it. And the water got warmer and warmer.
At the time, biologists thought life would not tolerate temperatures anywhere near 80 degrees Celsius. But Brock kept finding bacteria, so he kept on looking. Eventually, he found organisms that could live and reproduce near the temperature of boiling water -- 100 C.
The prize of his collection was an organism he named Thermus aquaticus (for its affinity for hot water) and deposited in a public repository for study by other scientists.
Thermus aquaticus in an outflow channel of a hot spring at Yellowstone. Courtesy of Thomas D. Brock.
Over the years, T. aquaticus proved to be very interesting indeed. For one thing, it was one of at least 50 species of thermophilic bacteria which tolerate or require temperatures near water's boiling point.
For another, it was the first of the Archaea, ancient microorganisms that some scientists now regard as a separate kingdom of life. (We'll discuss the grand plan of life later, but you can jump ahead if you wish).
Because thermophiles are ancient, and because they prefer the steamy conditions that were typical of the early Earth, many scientists think they may also tell us about the origin of life itself. Here's new information on the astonishing number of bacteria on Earth. Most live underground.
To any basic scientist, those contributions would be enough. But the thermophiles turned out to be an extraordinarily useful group of bugs.
That's because their enzymes (defined) work in high temperatures, where chemical reactions occur more quickly. Thus thermophile-derived enzymes are used to convert millions of pounds of corn (maize) into sugar to sweeten soft drinks.
But more important, at least to scientists who don't guzzle fizzy pop at the lab bench, Thermus aquaticus supplied TAQ polymerase, the essential enzyme for polymerase chain reaction, AKA PCR.
PCR is an artificial technique for something that living critters do every day -- replicate DNA. But PCR is the rocket ship of replication, since it allows you to multiply a piece of DNA billions of times in a few hours. That produces enough DNA to analyze to your heart's content -- for genetic engineering, biotechnology, and forensic purposes.
PCR depends on TAQ polymerase, and the battle over rights to this enzyme has raged for years. In the summer of 1996, the European Patent Office again rejected claims for the patent on TAQ polymerase by Roche Corp., opening the door to competing manufacturers.
Aware that PCR, not to mention soda pop, is a billion-dollar industry, corporations and scientists around the world are frantically searching for other thermophilic organisms, with equally useful enzymes. They're looking in odd places -- not just hot springs and volcanoes, but also deep-sea vents, hot petroleum-bearing rock, the outflow of geothermal power plants, and smoldering piles of garbage.
For the latest word on "Microbial Life in Hyperthermal Environments," see the bibliography.
Otherwise, let's grab a snorkel and go prowling for a glow-in-the-dark
squid.
