How Extremophiles Work Adapted from an article by Jacob Silverman Introduction to How Extremophiles Work What is your ideal environment to live in? Sunny, 72˚ Fahrenheit (22˚ Celsius)? How about living in nearly boiling water that’s so acidic it eats through metal? How about living in a muddy, aquatic environment without oxygen, that is far saltier than any ocean? If you’re an extremophile, that might sound perfect! Extremophiles are organisms that live in “extreme” environments. The name literally means extreme-loving. These hardy creatures are remarkable. The environments they live in are truly severe and are very different from our normal, moderate environments. Ironically, extremophiles couldn’t survive in our normal environments. For example, the microorganism Ferroplasma aci-diphilum, needs a large amount of iron to survive. These quantities of iron would kill most other life forms. The discovery of extremophiles, beginning in the 1960s, has caused scientists to rethink how life began on Earth. Many types of bacteria have been found deep underground, an area previously considered a dead zone (because of the lack of sunlight), but it is now seen as a clue to life’s origins. In fact, the majority of the Earth’s bacteria live underground. These specialized, rock-dwelling extremophiles are called endoliths. Scientists hypothesize that endoliths may absorb nutrients moving through rock veins or live on inorganic (nonliving) rock matter. Some endoliths may be genetically similar to the earliest forms of life that developed around 3.8 billion years ago. (OVER->) 1 Extreme Environments An environment is called extreme only in relation to what is normal for humans. But, for extremophiles, their favored environments are “normal”. Here’s a list of some additional names used to classify specific types of extremophiles: *Acidophile: likes low pH (acidic) environments * Alkaliphile: like high pH (alkaline) environments * Cryophile: loves extremely cold temperatures * Halophile: thrives in very salty environments * Piezophile/Barophile: likes high pressures * Psychrophile: flourishes in low temperatures * Xerophile: likes environment with little water * Thermophile: does well in temperatures of 104˚Farenheit or higher (40˚ Celsius). * Hyperthermophile: blooms at temperatures of 176˚ Fahrenheit or higher (80˚ Celsius) * Anaerobic extremophile: thrives in areas without oxygen; some cannot grow where there is oxygen. There are also methanogens, some of which live in cows’ intestines and produce methane (a gas) as a byproduct. Toxitolerant extremophiles do well in highly toxic surroundings, such as the radiation-charged area around the Chernobyl nuclear site. (Chernobyl is a town in the Ukraine, formerly part of the Soviet Union. There was a nuclear reactor accident at the Chernobyl Nuclear Power Plant on April 26, 1988, which released radiation into the nearby environment.) 2 Many notable extreme environments also play host to extremophiles. Numerous geysers around the world have extremophiles living in their hot pools and vents. In the United States, Yellowstone National Park has thousands of geysers, springs and other geothermal features, with varying levels of temperature, acidity, and sulfur. Many types of extremophiles exist in these surroundings. Another example is the Rio Tinto River in Spain. The Rio Tinto is full of heavy metals because the region has been a rich mining area for thousands of years. Likewise, Iron Mountain in Northern California has water so full of heavy metals and acids (natural byproducts of mining) that it can eat through a metal shovel in a day. But even here, deep in underground mines, microbes (microscopic organisms) manage to survive. Learning from Extremophiles In the 1960s, Dr. Thomas Brock, a biologist, was investigating bacteria in Yellowstone National Park’s hot springs when he stumbled on something for the first time. Bacteria living in the area were thriving in super high temperatures. The newly named Thermus aquaticus lived in water that was nearly 212˚ Fahrenheit (100˚ Celsius)— practically boiling. T. aquaticus provided the basis for a groundbreaking discovery in biology. This extremophile produces an enzyme called TAQ polymerase. (An enzyme is a complicated molecule that is produced by cells and starts a specific biochemical reaction or makes it go faster.) Specifically, T. aquaticus produces an enzyme that allows a scientist to replicate a piece of genetic material (DNA) billions of times over a few hours. Why is this groundbreaking? Without this process, nearly all work requiring DNA replication, from forensic science to genetic testing, would not be possible. (Over->) 3 Enzymes from alkaliphiles are used for making laundry and dishwashing detergents. They are used for removing hair from animal hides. Another alkaliphile from Yellowstone is used making paper and treating waste. NASA is studying an extremophile, Deinococcus radiodurans, that is very resistant to radiation. This microbe can withstand radiation 500% higher than would be deadly to humans. For NASA, this extremophile could offer clues for building better spacesuits and spacecrafts. Silverman, Jacob. “How Extremophiles Work.” 13 January 2009. How Stuff Works.com http://science.howstuffworks.com/cellular-microscopic- biology/extremophile.htm > 06 August 2009. 4 .