Strategies for Possible Survival on Earth
Posted by Richard Conniff on March 12, 2013
Here’s another misguided piece of extraterrestrial wishful thinking, in the form of a press release purporting to tell us the secrets of life on Mars. Except that the creatures being studied live, um, right here on Earth. But it is apparently too boring to just take them for what they are.
The study comes from the University of Maryland School of Medicine and the money to pay for it comes, wait, wait, from NASA.
You may recall that NASA got in trouble for this sort of thing not long ago: In 2010, a scientist funded by the space agency purported to have found a prototype for extraterrestrial life in a bacterial species that substituted arsenic for phosphorous in fundamental biochemistry. That species lived not on Mars but in California’s Mono Lake. And as subsequent studies have shown, it didn’t really do what the research suggested at all.
My favorite piece of outer space woo-woo thinking along these lines was a 2011 article in Acta Aeronautica, a scholarly journal, arguing that the real value of studying how species on Earth communicate is to “de-provincialize” our thinking about how to communicate with extraterrestrials. Think about this next time you are talking to your dog. (That one was paid for by the SETI Institute, which, thanks to a rare act of Congressional wisdom, no longer receives its funding via NASA .)
Sooner or later, we are going to figure out that we have absolutely no chance of surviving on other planets, and only the teeny-eeny-weaniest chance of ever communicating with life forms on other planets.
Meanwhile, by even the most conservative account, there are at least eight million species here on Earth we have not yet even identified. And they are worth studying entirely for themselves. They are worth studying not least so we can figure out how not to annihilate them. Maybe then we can figure out how to survive on the only planet we will ever know.
But for now, here we go again, with “Strategies for Possible Survival on Mars” that turn out to be real strategies for surviving on Earth.
Strategies for Possible Survival On Mars: Scientists Found Differences in Core Proteins from a Microorganism That Lives in a Salty Lake in Antarctica
Mar. 11, 2013 — Research from the University of Maryland School of Medicine has revealed key features in proteins needed for life to function on Mars and other extreme environments. The researchers, funded by NASA, studied organisms that survive in the extreme environment of Antarctica. They found subtle but significant differences between the core proteins in ordinary organisms and Haloarchaea, organisms that can tolerate severe conditions such as high salinity, desiccation, and extreme temperatures. The research gives scientists a window into how life could possibly adapt to exist on Mars.
The study, published online in the journal PLoS One on March 11, was led by Shiladitya DasSarma, Ph.D., Professor in the Department of Microbiology and Immunology at the University of Maryland School of Medicine and a research scientist at the Institute of Marine and Environmental Technology.
Researchers found that Haloarchaeal microbes contain proteins that are acidic, with their surface covered with negatively charged residues. Most ordinary organisms contain proteins that are neutral on average. The negative charges found in the unusual organisms keep proteins in solution and help to hold on tightly to water, reversing the effects of high salinity and desiccation.
In the current study, the scientists identified additional subtle changes in the proteins of one Haloarchaeal species named Halorubrum lacusprofundi. These microbes were isolated from Deep Lake, a very salty lake in Antarctica. The changes found in proteins from these organisms allow them to work in both cold and salty conditions, when temperatures may be well below the freezing point of pure water. Water stays in the liquid state under these conditions much like snow and ice melt on roads that have been salted in winter.
“In such cold temperatures, the packing of atoms in proteins must be loosened slightly, allowing them to be more flexible and functional when ordinary proteins would be locked into inactive conformations” says Dr. DasSarma. “The surface of these proteins also have modifications that loosen the binding of the surrounding water molecules.”
“These kinds of adaptations are likely to allow microorganisms like Halorubrum lacusprofundi to survive not only in Antarctica, but elsewhere in the universe,” says Dr. DasSarma. “For example, there have been recent reports of seasonal flows down the steep sides of craters on Mars suggesting the presence of underground brine pools. Whether microorganisms actually exist in such environments is not yet known, but expeditions like NASA’s Curiosity rover are currently looking for signs of life on Mars.”
“Dr. DasSarma and his colleagues are unraveling the basic building blocks of life,” says E. Albert Reece, M.D., Ph.D., M.B.A., Vice President for Medical Affairs at the University of Maryland and John Z. and Akiko K. Bowers Distinguished Professor and Dean of the University of Maryland School of Medicine. “Their research into the fundamentals of microbiology are enhancing our understanding of life throughout the universe, and I look forward to seeing further groundbreaking discoveries from their laboratory.”
Dr. DasSarma and his colleagues are conducting further studies of individual proteins from Halorubrum lacusprofundi, funded by NASA. The adaptations of these proteins could be used to engineer and develop novel enzymes and catalysts. For example, the researchers are examining one model protein, β-galactosidase, that can break down polymerized substances, such as milk sugars, and with the help of other enzymes, even larger polymers. This work may have practical uses such as improving methods for breaking down biological polymers and producing useful materials (see Karan et al. BMC Biotechnology).Share this story on Facebook, Twitter, and Google:
Other social bookmarking and sharing tools:
- Ram Karan, Melinda D Capes, Priya DasSarma, Shiladitya DasSarma. Cloning, overexpression, purification, and characterization of a polyextremophilic β-galactosidase from the Antarctic haloarchaeon Halorubrum lacusprofundi. BMC Biotechnology, 2013; 13 (1): 3 DOI: 10.1186/1472-6750-13-3
- Shiladitya DasSarma, Melinda D. Capes, Ram Karan, Priya DasSarma. Amino Acid Substitutions in Cold-Adapted Proteins from Halorubrum lacusprofundi, an Extremely Halophilic Microbe from Antarctica. PLoS ONE, 2013; 8 (3): e58587 DOI: 10.1371/journal.pone.0058587