Mechanisms Used by Extremophiles
Techniques for Microbial Life Survival in Extreme Environments
Oct 25, 2009
Extremophiles come in many different types, preferring widely varied conditions. Often existence in extreme environments requires extreme life adaptations.
An extremophile can be one of many different types of organisms. Some are aerobic and some anaerobic. Some exist best in extreme environments consisting of high temperatures or low pH, while others require the complete opposite. Here are some of the most prominent types of extreme life scientists have found around the globe.
Extremophiles that Live in Extreme Temperature and pH Conditions
- Thermophiles and Hyperthermophiles: Thermophiles are heat loving extremophile microorganisms, preferring temperatures over 104 degrees F. Hyperthermophiles prefer even hotter conditions, over 176 degrees F. Most thermophilic microorganisms are bacteria and they can be found in places as extreme as hot springs, geysers and the insides of volcanoes. The most famous thermophile is Thermus aquaticus, source of the biotechnology compound Taq polymerase.
- Acidophiles and Alkaliphiles: These kind of extreme organisms love acidic or basic conditions (ph under 3.0 and over 9.0 respectively), such as inside the human stomach (an acidic environment) or in extremely alkaline lakes.
- Methanogens: Methanogens are organisms which use energy to produce methane and many, but not all, are considered extremophiles. Some methanogens are also thermophiles or hydrothermophiles, including those which live in hot springs in Yellowstone National Park. Methanogens are anaerobic and cannot survive in high oxygen environments.
- Radioresistant Bacteria: Radioresistant extremophiles survive in conditions with high radiation. They have been found in nuclear waste sites and many scientists are trying to find ways to use them to help clean up nuclear waste. The most famous radiophile is Deinococcus radiodurans, which is also considered a polyextremophile since it can survive in a variety of extreme conditions.
- Endoliths: Endoliths are extreme microorganisms that live inside rock. Some endoliths have been found in surface rocks, while others have been discovered deep in the Earth's crust and under the ocean floor.
- Halophiles: These microorganisms live in extreme life conditions characterized by high salt concentrations. They have been found in extremely saline lakes, such as the Dead Sea and Utah's Great Salt Lake. Many anaerobic halophiles are dependent on their extreme environments and will quickly die if removed from an area of high salt. Some mild halophiles have been found as a contaminant in salty foods such as soy sauce. Astrobiologists are particularly interested in haophiles, since the Meridiani Planum on Mars has high concentrations of salt left over from an ancient salty sea.
For Further Reading:
Horikoshi, Koki and Grant, William D. Extremophiles: Microbial Life in Extreme Environments. Wiley-Liss. 1998
DasSarma, S. and P. DasSarma 2006. "Halophiles", Encyclopedia of Life Sciences, Wiley, London.
The copyright of the article Mechanisms Used by Extremophiles in Biology is owned by Bridget Coila. Permission to republish Mechanisms Used by Extremophiles in print or online must be granted by the author in writing.
 |
 |
 |
