Extremophiles are organisms that can thrive in unexpectedly hostile environments. These include bacteria and fungi growing in extremely hot, cold, nutrient-deprived, or salty environments. Experiments that purposely stress extremophiles in order to test their limits have shown that earth's tiniest cells have many survival tricks up their sleeves.
Why are scientists interested in extremophiles? It comes down to dollars and astrobiology--the search for extraterrestrial life. NASA-funded studies are using earth's extremophiles to explore the possibility that living cells exist elsewhere,1 since it is much less expensive to look for hardy organisms here than it is to spend billions of dollars on planetary explorations--which so far have gathered decades of negative news about the existence of life outside of the earth.2
Astrobiologists reason that if hardy cells can survive "impossible" places on earth, maybe they are also surviving hostile environments on other planets or moons, even though no traces of life have been found out in space.
A new, non-NASA related study in the Proceedings of the National Academy of Sciences sought to test the limits of cold tolerance in a species of fungus that had been screened for extreme cold resistance. The fungus was introduced to fructose, which falls into a category of chemicals called "chaotropes" that at room temperature disrupt molecules used in cell processes. When the fungus was grown at near-freezing temperatures, it accumulated extra fructose. The fungus cells also excluded chemicals that at room temperature help to keep cell chemistry orderly and operating smoothly.
As the water in the organism began to thicken toward freezing, the cells' vital chemical reactions likely slowed down. So, the cells "knew" that if they could find chemicals from their environment that could disrupt the freezing process, it would keep their internal chemicals unfrozen enough to continue interacting, which would keep the cell alive.
Not only could the fungus adjust to extremely low temperatures, but the cells somehow produced and maintained their own disrupting "antifreeze" chemical--glycerol--to help them survive the cold. The authors of the study stated, "In accordance with our hypothesis (but, nevertheless, to our surprise), cells preferentially synthesized and accumulated a chaotropic-compatible solute, glycerol."3
What was surprising about this find? They explained that "it is energy expensive" to manufacture and retain the glycerol. Eventually, though, the cells spend so much energy on this that there is none left for other cell processes. When the temperature dipped below 1.7 degrees Celsius, the fungus died, probably because it could no longer afford to retain chaotropes.4
Although the authors stated that "this information can enhance the precision of models used to predict if extraterrestrial and other hostile environments are able to support life,"3 what it really does is enhance scientific knowledge of the expertise of life's Designer.
An earth-bound fungus' abilities to "preferentially synthesize and accumulate" glycerol imply an array of features that should not only have surprised these researchers by their effectiveness, intricacies, and miniaturization, but should have shown the implausibility of cells having evolved through random processes anywhere in the universe.
First, the fungus has a mechanism that can distinguish the desired chemical from all others present. Second, it must have some built-in information about the significance of that chemical--i.e., an "awareness" that it can support the cell in cold temperatures. Third, it has to have a mechanism to physically "grab" each chemical, and a switch to turn that mechanism on at the right temperature--which implies an internal thermometer.
Fourth, an array of cellular machinery is needed to manufacture glycerol. Fifth, a sensitive and effective set of molecular pumps, as well as their on/off switches and energy sources, must constantly keep the glycerol and fructose inside the cell, since concentrated glycerol tends to diffuse outward. Surely this fungus was a product of a wise and benevolent Creator, who equipped it with the precise biological features needed to survive extreme cold.
Spectacular cellular systems like these have some researchers in a quandary. For example, a recent article in Astrobiology Magazine quoted astrophysicist Paul Davies' new book reflecting on the absence of evidence for extraterrestrials. In The Eerie Silence: Renewing Our Search for Alien Intelligence, Davies wrote:
To a physicist like me, life looks to be a little short of magic: all those dumb molecules conspiring to achieve such clever things! How do they do it? There is no orchestrator, no choreographer directing the performance, no esprit de corps, no collective will, no life force--just mindless atoms pushing and pulling on each other, kicked about by random thermal fluctuations. Yet the end product is an exquisite and highly distinctive form of order.5
What makes that "form of order" distinctive are "specifications." Specified order is equal to information, which is exclusively the product of intelligence. Davies asks good questions. But as long as he insists, against the evidence, that "there is no orchestrator," he restricts himself to a dark conceptual box labeled "naturalism," where inept answers suggesting "magical" forces are all that is available.
The discovery that certain fungi can survive in colder temperatures by means of fantastic molecular machinery makes mincemeat out of the strange argument that finding extremophiles on earth indicates that they might also exist on other planets. It does, however, show evidence for a Creator.
- Fact sheet from NASA Astrobiology Program. Posted on astrobiology.nasa.gov, accessed April 22, 2010.
- For example see this recent summary: Moskowitz, C. NASA: Claims of Life on Mars 'Positively False.' Space.com. Posted on space.com April 29, 2010, accessed May 4, 2010.
- Chin, J. P. et al. 2010. Solutes determine the temperature windows for microbial survival and growth. Proceedings of the National Academy of Sciences. 107 (17): 7835-7840.
- However, the fungi were able to manufacture spores that withstood an incredible -70 degrees Celsius.
- Davies, P. 2010. The Eerie Silence: Renewing Our Search for Alien Intelligence. Boston: Houghton Mifflin Harcourt. Quoted in Mullen, L. The Eerie Silence. Astrobiology Magazine. Posted on astrobio.net April 12, 2010, accessed April 21, 2010.
Image credit: NASA
* Mr. Thomas is Science Writer at the Institute for Creation Research.
Article posted on May 11, 2010.