Great Bugs of Fire
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Great bugs of fire
16 September, 1998: They may be
small, but they're very hot. They're the archaea, an ancient
branch of microbial life on Earth discovered by scientists in
1977. Unlike the better known bacteria and eukaryotes (plants
and animals), many of the archaea can thrive in extreme environments
like volcanic vents and acidic hot springs. They can live without
sunlight or organic carbon as food, and instead survive on sulfur,
hydrogen, and other materials that normal organisms can't metabolize.
It may sound like science fiction, but many scientists are working
rapidly to explore the biology as well as the practical benefits
of these recently discovered life forms.
Protein from volcano-loving bug crystallized in space
These hot springs at Yellowstone owe their vibrant colors to thermophilic (heat-loving) microorganisms, many of which can live and reproduce at temperatures near the boiling point of water. Photo courtesy Prof. Thomas D. Brock, University of Wisconsin.
This is one of several stories summarizing results from the 16-day Life and Microgravity Spacelab (LMS), which flew June 20-July 7, 1996, aboard Space Shuttle Columbia (STS-78, at launch, left). It featured 40 scientific investigations from 10 countries. Its record development and cost - each experiment cost about half of most Spacelab experiments - make LMS an example of how future space station missions can control experiments remotely from locations around the globe. LMS results were recently published by NASA (see below). The investigation in this story used the European Space Agency's Advanced Protein Crystallization Facility.
Other LMS stories:
- Nature's sugar high - Spacelab successfully crystallizes an intensely sweet protein from the African Serendipity Berry that has 3000 times the kick of table sugar - and no calories.
- Great Bugs of Fire - Spacelab crystallizes a protein from a very weird, and surprisingly common, volcano-loving bug. Scientists hope to discover how these organisms can survive in such extreme conditions. (this story)
- Nature's "electronic ink" - Another extremophile - a bacterium which thrives in high-salt conditions - produces a fascinating protein which changes color extremely efficiently. Crystals grown by Spacelab make scientists hopeful that they can understand the biological function and apply it to, for example, artificial retinas for people.
The red of these rocks is produced by sulfolobus solfataricus, near Naples, Italy.
In the microgravity environment of the Space Shuttle scientists are able to grow macromolecular crystals with a high degree of purity. Using a process called "X-ray crystallography" they can map the structure of proteins and learn how they work. more information
When stored at room temperature, these molecules from volcanic microbes are in the "deep freeze" compared to their normal lives, thus offering tremendously extended shelf-life and stability in commercial use.
The first Archaea-related products were DNA polymerases for the research market. For example, New England Biolabs, a Beverly, Mass.-based biotechnology company, sells Vent and Deep Vent polymerases, used in DNA sequencing. These enzymes originally were isolated from hyperthermophiles associated with oceanic hydrothermal vents. Without analysis of these fiery microbes, neither the modern identification of human genetic diseases nor the use of DNA evidence in legal courts would even have been realized.
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Researchers say that the heat and geochemical conditions in volcanic regions may be similar to conditions that existed on the young, water-covered, cooling Earth. Almost like a creature from science fiction, the volcanic microbe is different from the two other basic branches of life: bacteria and eukaryotes. The prokaryotes are the bacteria, while eukaryotes are the so-called higher forms of life, including humans, plants and animals.
A major difference is that eukaryotes put their genes inside a nucleus, while prokaryotes do not. In the archaea, there is no nucleus, but many genes behave like those in higher organisms. Archaea are thought to have a common ancestor with bacteria, but billions of years ago the third domain, eukaryotes, broke off from archaea, eventually developing into plants, animals and us. Archaea include microbes that live at the extremes of the planet - the very, very cold, hot or high-pressure places that no other form of life could endure.
As such, archaea are the extremophiles who boldly thrive where no other life form would go. Some scientists have suggested that as such, archaea may represent the earliest form of life and thus may be the most likely form of life existing on other planets. About 500 species of archaea are now identified, but speculation may not be far off in projecting that given the difficulties of collecting and classifying them, there may be a million others. The life form is thought to produce about 30 percent of the biomass on Earth, much of it in the Antarctic Ocean.
In fact, as far back as 1994, Myrna Watanabe, a biotechnology consultant, wrote that the existence of this third branch of life "here on Earth has led scientists to realize that planets they hitherto assumed to be lifeless might support life."
The large Jovian moon Europa may harbor liquid water beneath its frozen crust. Many believe that large reservoirs of water hold out the tantalizing possibility of organisms living on this distant world.
Biotechnology in space
Some estimates suggest that human biology depends on the action of nearly half a million different enzymes and proteins. In fewer than 1 case in 100, we have a three-dimensional picture of shape and function of these complex chemicals. Since 1984, the Space Shuttle has carried experiments to determine the structures of large, biologically important molecules. This research has compiled results for a host of human diseases ranging from insulin (for the control of diabetes) to one enzyme called reverse transcriptase that can be blocked to inhibit HIV infection.
In comparing more than 33 such different biological molecules crystallized on the Shuttle and also in similar conditions on earth, space produced larger space crystals in 45% of the cases and new structures in nearly 20% of the cases. As many as half the space crystals had a 10% or better improvement in the x-ray brightness or the crystallographic resolution. Both are important to determining these large molecules' shape and exact atomic positions.
Adriana Zagari, Center for the Study of Biocrystallography, CNR and Department of Chemistry, University of Naples Federico II, Naples, Italy
I. Esposito, F. Sica, G. Sorrentino, R. Berisio, L. Carotenuto, A. Giordano, C.A .Raia, M. Rossi, V.S. Lamzin, and K.S. Wilson, MARS, IBPE, Naples and EMBL, Hamburg Germany
www.Microgravity.com general information about low-gravity science, including
combustion and protein crystal growth.
Life and Microgravity Spacelab web site
Microgravity Research Program Officeat Marshall has a wealth of information and background on various microgravity projects
Life and Microgravity programmatic information from NASA headquarters.
(Note: NASA does not endorse external sites)
The Why Files? on heat-loving (thermophilic) bacteria
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