May 24, 2013
Extreme Arctic Bacteria Discovered That Could Survive On Mars
Lee Rannals for redOrbit.com - Your Universe Online
A recent discovery made on Ellesmere Island in the Canadian High Arctic opens up the possibly that bacteria could grow on the surface of Mars.Scientists recently found that a bacterium was able to thrive at five degrees Fahrenheit, which is the coldest temperature ever reported for bacterial growth. The bacterium provides clues about preconditions for microbial life on both the Saturn moon Enceladus and Mars.
The researchers discovered the bacterium Planococcus halocryophilus OR1 after screening about 200 separate High Arctic microbes looking for the microorganism best adapted to the harsh conditions of the Arctic permafrost.
”We believe that this bacterium lives in very thin veins of very salty water found within the frozen permafrost on Ellesmere Island,” said Lyle Whyte, professor of environmental microbiology at McGill University and team leader of the study.
“The salt in the permafrost brine veins keeps the water from freezing at the ambient permafrost temperature, creating a habitable but very harsh environment. It´s not the easiest place to survive but this organism is capable of remaining active (i.e. breathing) to at least -25ºC (-13ºF) in permafrost.”
The team studied the genomic sequence and other molecular strains of the bacteria and found that it adapts to the extremely cold, salty conditions thanks to key modifications in its cell structure. These modifications include changes to the membranes that envelop the bacterium and protect it from the hostile environment. They also found that P. halocryophilus OR1 maintains high levels of compounds inside the bacterial cell that act as a molecular antifreeze to keep the microbe from freezing solid.
“I´m kind of proud of this bug," Whyte said. "It comes from the Canadian High Arctic and is our cold temperature champion, but what we can learn from this microbe may tell us a lot about how similar microbial life may exist elsewhere in the solar system.”
Another microorganism was discovered in the extreme environment of Antarctica. Scientists reported back in March that the differences in the core proteins of Antarctic extremophile bacteria allow it to tolerate severe conditions like extreme temperatures and high salt concentrations.
“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” said lead author Shiladitya DasSarma from the Department of Microbiology and Immunology at the University of Maryland.
This team said that the presence of frozen ice and water on Jupiter's moon Europa could make it an ideal place for these microorganisms to survive.