Extremophiles: More Than Just A Cool Name

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What are extremophiles?
Extremophiles are organisms that live in extreme conditions. The extreme-ness of these conditions are anthropocentrically derived, meaning they are extreme as compared to human life, and up until the 1960s we didn?t even imagine life of any kind could exist in some of the places extremophiles call home.

Extremophiles are so cool that they have their own domain name: Archaea. Classified as bacteria in the past, some microbiologists hypothesized that archaea were fundamentally different from bacteria in some interesting ways. Their cell wall doesn?t contain peptidoglycan?the primary difference from bacteria?and their plasma membranes are made from lipid-like materials. Like prokaryotes, archaea DNA float freely in the cell, but RNA polymerase and ribosomal proteins are similar to that of eukaryotes. In 1996, archaea was generally accepted as a distinct domain, with some microbiologists suggesting it lies between prokaryotes and eukaryotes.

Where on Earth do they live?
The type of neighborhood an extremophile lives in depends upon which type of archaea it is. There are four main types of archaea, each calling a very different and extreme environment home.

* Archaea Types #1 and #2: These ruffians live in very hostile environments, like salt lakes, hot springs, and mid-ocean thermal vents.

* Archaea Type #3: These guys are not picky eaters, and can metabolize chemicals that would be dangerous to humans, some just pretty gross, and makes methane as a by-product.

* Archaea Type #4: This type of extremophiles lives by reducing sulfates.

* Other Types of Archaea: Some can use simple elementary chemicals to live on, like hydrogen and sulfur.

Finding life in bizarrely extreme environments was a shocker, and now scientists are noting what they call ?The Goldilocks Zone??the realm of habitability for life is far larger than even recently believed. Life abounds in the deep hot biosphere, in its geysers, deep-sea hydrothermal vents, and deep hot crustal rocks. The hyperthmophilic bacteria and archaea found in these areas may hold vital keys to the origin of life.

Living, viable, and even dormant ancient microorganisms also abound in the deep and frigid biosphere; in its polar ice caps, glaciers, permafrost, and deep-sea sediments. Cold-loving and cold-tolerant microbes (called psychrophiles and psychrotrophs) include not only archaea, but also bacteria, cyanobacteria, and even eukaryotic microorganisms such as yeasts and diatoms. As recently as 1998, scientists exploring a microworld locked in ancient ice found a wide range of lifeforms never seen before. Some of the dust particles associated with these have unusual spectra, which maybe cosmic dust particles!

In alkaline springs, small amounts of hydrogen sulfide provide a source of energy for archaean life. The microorganisms live attached to the siliceous walls of the spring basin, where they are hard to see, but can be studied using a little trick. Microscope slides are immersed in the boiling water, and the archaea colonize on their surfaces. Several days later, the slides can be taken out and the new colonies studied.

How we can use them to our advantage?
Discovered less than 40 years ago, extremophiles are already being exploited for human use in hundreds of ways. Their enzymes?biolocial catalysts?help extremophiles to function in brutal circumstances. Like synthetic catalysts, these proteins speed up chemical reactions without being altered themselves. Extremozymes have technobiological application in consumer products ranging from laundry detergent to antibiotics.

Most extremozymes in commercial use so far are not altered much from their original state. But rational design and other approaches promise to enhance extremozymes, and may help to convert enzymes from ordinary microbes into artificial extremozymes.

The lexicon rising up around this field is vast, and the following terms lend insight into the field.

* Alkaliphile: An organism with optimal growth at pH values above 10.

* Barophile: Organism that lives optimally at high hydrostatic pressure.

* Endolith: An organism that lives in rocks (how exciting is that?!).

* Extreme Acidophile: Organism with a pH optimum for growth at or below pH 3.

* Halophile: An organism requiring at least 0.M salt for growth.

* Hyperthermophile: An organism having a growth temperature optimum of 80˚C or higher.

* Oligotroph: Organism with optimal growth in nutrient limited conditions.

* Psychrophile: An organism having a growth temperature optimum of 15˚C or lower, and a maximum temperature of 20˚C. (The methane ice work at the top of this page is an example, is one to two inches in length, and lives at the bottom of the Gulf of Mexico.)

* Toxitolerant: Organism able to withstand high levels of damaging agents. For example, living in water saturated with benzene, or in the water-core of a nuclear reactor!

* Xerotolerant: An organism capable of growth at low water activity, like an extreme halophile or endolith.

Are Martians extremophiles?
Could be. Instead of looking for beings roughly the size and make-up of Earthlings, the archaea kingdom of life is now the focus of our search for life on other planets.

One of Jupiter?s moons is especially promising. Europa has black smokers like those on Earth?s mid-ocean ridges; could there be rich extremophile civilizations around Europa?s nutrient-rich vents, as we?ve recently found around Earth?s? NASA is planning to find out, with several Europa missions in the works, including a lander with a drilling device and a submarine explorer.

Microorganisms found in the permafrost, glaciers, and polar ice caps of Earth also have a profound significance to astrobiology. Dormant ancient microbes that have been frozen in glacial ice or permafrost can remain viable by cryopreservation?being frozen?and resume metabolic activity upon thawing, even after thousand or millions of years! Conditions are right for this type of finding in the ice caps of Mars, or the many other icy bodies of the solar system.

The big deal of extremophiles.
The tree of life has been redrawn with the discovery and study of extremophiles, introducing us to the Archaea domain. To date, more than 50 species of hyperthmophiles alone have been isolated. Cold environments make up over half of the Earth?s surface, and we?ve just scratched the surface on what may be living there...and the implications for life on other planets. Extremozymes are being harvested, produced through recombinant DNA technology without massive culturing of the source. Moreover, extremophiles are science-fiction exciting. What we thought we knew has been stretched and twisted, opening up a new realm of discovery and a paradigm shift on life.

Extremophiles: More Than Just A Cool Name

What are extremophiles?
Extremophiles are organisms that live in extreme conditions. The extreme-ness of these conditions are anthropocentrically derived, meaning they are extreme as compared to human life, and up until the 1960s we didn�t even imagine life of any kind could exist in some of the places extremophiles call home.

Extremophiles are so cool that they have their own domain name: Archaea. Classified as bacteria in the past, some microbiologists hypothesized that archaea were fundamentally different from bacteria in some interesting ways. Their cell wall doesn�t contain peptidoglycan�the primary difference from bacteria�and their plasma membranes are made from lipid-like materials. Like prokaryotes, archaea DNA float freely in the cell, but RNA polymerase and ribosomal proteins are similar to that of eukaryotes. In 1996, archaea was generally accepted as a distinct domain, with some microbiologists suggesting it lies between prokaryotes and eukaryotes.

Where on Earth do they live?
The type of neighborhood an extremophile lives in depends upon which type of archaea it is. There are four main types of archaea, each calling a very different and extreme environment home.
Archaea Types #1 and #2: These ruffians live in very hostile environments, like salt lakes, hot springs, and mid-ocean thermal vents.
Archaea Type #3: These guys are not picky eaters, and can metabolize chemicals that would be dangerous to humans, some just pretty gross, and makes methane as a by-product.
Archaea Type #4: This type of extremophiles lives by reducing sulfates.
Other Types of Archaea: Some can use simple elementary chemicals to live on, like hydrogen and sulfur.

Finding life in bizarrely extreme environments was a shocker, and now scientists are noting what they call �The Goldilocks Zone��the realm of habitability for life is far larger than even recently believed. Life abounds in the deep hot biosphere, in its geysers, deep-sea hydrothermal vents, and deep hot crustal rocks. The hyperthmophilic bacteria and archaea found in these areas may hold vital keys to the origin of life.

Living, viable, and even dormant ancient microorganisms also abound in the deep and frigid biosphere; in its polar ice caps, glaciers, permafrost, and deep-sea sediments. Cold-loving and cold-tolerant microbes (called psychrophiles and psychrotrophs) include not only archaea, but also bacteria, cyanobacteria, and even eukaryotic microorganisms such as yeasts and diatoms. As recently as 1998, scientists exploring a microworld locked in ancient ice found a wide range of lifeforms never seen before. Some of the dust particles associated with these have unusual spectra, which maybe cosmic dust particles!

In alkaline springs, small amounts of hydrogen sulfide provide a source of energy for archaean life. The microorganisms live attached to the siliceous walls of the spring basin, where they are hard to see, but can be studied using a little trick. Microscope slides are immersed in the boiling water, and the archaea colonize on their surfaces. Several days later, the slides can be taken out and the new colonies studied.

How we can use them to our advantage?
Discovered less than 40 years ago, extremophiles are already being exploited for human use in hundreds of ways. Their enzymes�biolocial catalysts�help extremophiles to function in brutal circumstances. Like synthetic catalysts, these proteins speed up chemical reactions without being altered themselves. Extremozymes have technobiological application in consumer products ranging from laundry detergent to antibiotics.

Most extremozymes in commercial use so far are not altered much from their original state. But rational design and other approaches promise to enhance extremozymes, and may help to convert enzymes from ordinary microbes into artificial extremozymes.

The lexicon rising up around this field is vast, and the following terms lend insight into the field.
* Alkaliphile: An organism with optimal growth at pH values above 10.
* Barophile: Organism that lives optimally at high hydrostatic pressure.
* Endolith: An organism that lives in rocks (how exciting is that?!).
� Extreme Acidophile: Organism with a pH optimum for growth at or below pH 3.
� Halophile: An organism requiring at least 0.M salt for growth.
� Hyperthermophile: An organism having a growth temperature optimum of 80˚C or higher.
� Oligotroph: Organism with optimal growth in nutrient limited conditions.
� Psychrophile: An organism having a growth temperature optimum of 15˚C or lower, and a maximum temperature of 20˚C. (The methane ice work at the top of this page is an example, is one to two inches in length, and lives at the bottom of the Gulf of Mexico.)
� Toxitolerant: Organism able to withstand high levels of damaging agents. For example, living in water saturated with benzene, or in the water-core of a nuclear reactor!
� Xerotolerant: An organism capable of growth at low water activity, like an extreme halophile or endolith.

Are Martians extremophiles?
Could be. Instead of looking for beings roughly the size and make-up of Earthlings, the archaea kingdom of life is now the focus of our search for life on other planets.

One of Jupiter�s moons is especially promising. Europa has black smokers like those on Earth�s mid-ocean ridges; could there be rich extremophile civilizations around Europa�s nutrient-rich vents, as we�ve recently found around Earth�s? NASA is planning to find out, with several Europa missions in the works, including a lander with a drilling device and a submarine explorer.

Microorganisms found in the permafrost, glaciers, and polar ice caps of Earth also have a profound significance to astrobiology. Dormant ancient microbes that have been frozen in glacial ice or permafrost can remain viable by cryopreservation�being frozen�and resume metabolic activity upon thawing, even after thousand or millions of years! Conditions are right for this type of finding in the ice caps of Mars, or the many other icy bodies of the solar system.

The big deal of extremophiles.
The tree of life has been redrawn with the discovery and study of extremophiles, introducing us to the Archaea domain. To date, more than 50 species of hyperthmophiles alone have been isolated. Cold environments make up over half of the Earth�s surface, and we�ve just scratched the surface on what may be living there...and the implications for life on other planets. Extremozymes are being harvested, produced through recombinant DNA technology without massive culturing of the source. Moreover, extremophiles are science-fiction exciting. What we thought we knew has been stretched and twisted, opening up a new realm of discovery and a paradigm shift on life.