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NatureScience

Antarctic Science Team Discovers Hundreds of 'Extreme Microbes'

South Shetland Islands – In what would be the microbiological equivalent of discovering buried treasure, a team of Antarctic bioscientists, led by Jenny Blamey of the Biosciences Foundation of Santiago, Chile,  recently discovered a trove of some 300 microorganisms, 70% of which are previously unknown to science.

Location of the South Shetlands.

The team’s mission was to seek out extremophile microbes (in this case, mostly bacterial species) in this largely unexplored and climatically extreme region of the globe in the hopes of finding new bio-technological uses for these “biological resources”.  The region is subject to a combination of extremely low temperatures and high amounts of ultra-violet radiation — making it a near perfect, natural laboratory for  exploring the result of natural selection under extreme conditions.

The team could not have been more pleased with their success.

Chilean bioscientist team, unknown extreme microbes discovered
Chilean scientists sought organisms with traits that could be developed into useful biotechnologies.Jenny Blamey

Not surprisingly, the team uncovered numerous species of psychrophile bacteria which thrive at temperatures below 15º C, in addition to several kinds of halophiles (microbes tolerant of high saline conditions) and acidophiles and alkaliphiles (organisms that tolerate extremes in pH).These microbes accumulate molecules known as biostabilizers and may have applications for cosmetics, amongst other uses.

Some of the uncovered psychrophiles, however,  were new to science, and showed high resistance to ultra-violet radiation. It is believed that this resistance is due to a gene that encode a specialized enzyme that neutralizes reactive oxygen species (resulting from high UV exposure) that cause cell damage. This enzyme could one day be utilized in screens that protect people from UV radiation.

More surprising was the discovery of several thermophilic and hyperthermophilic species that are ecological adapted to temperatures above 50º C (over 90º F). This unusual find would seem to indicate an evolutionary history that predates the current (extreme cold) Antarctic environment

Deinococcus. radiodurans, radiation resistance
A tetrad of Deinococcus. radiodurans which can withstand up to 5000 times the amount of gamma radiation than any other organism on Earth

Perhaps most surprising, though, was the discovery of a previously unidentified species of Deinococcus bacteria living 15 meters below the permafrost. These highly robust bacteria are known for their ability to withstand exposure to radiation — specifically, gamma radiation — many thousands of times more than any other known organism. Curiously, these radiation levels, according to the scientists, have never existed on planet Earth. This has prompted speculation that this adaptation could have only resulted if the progenitor bacterial species evolved somewhere other than Earth, that is,  having an extraterrestrial origin.*

Another exploratory mission, led by Paris Lavin of the Chilean Antarctic Institute, focused on the isolated lagoons of King George Island (part of the Shetland chain) and investigated nearly 300 strains of actinomycetes, an order of bacteria that produce an antibiotic known as streptomycin. This particular form of the anti-biotic may prove to be medically useful as it evolved in isolation from other bacterial strains, and thus resistance to it would be minimal.

Blamey and colleagues were members of the Antarctic Scientific Expedition 47 (ECA-47) organized by the Chilean Antarctic Institute in Puntas Arenas. The expedition involved multiple research projects pursued over the course of the 2010 – 2011 southern summer.

*An alternative to the E.T.  theory: The evolving of resistance to high doses of gamma radiation (not present “on Earth”) may have resulted from quite ancient, (high) atmospheric bacteria which would have periodically been exposed to gamma ray bursts, perhaps even more massive bursts speculated to have caused/contributed to past extinctions. Also, a mutation that confers radiation resistance may have occurred which was highly generalized — providing more protection than is needed, similar to how our brains  produce more neurons (in infancy) than are needed as adults.

Some source material for this post came from the Nature News article: Antarctic microbes live life to the extreme by Patricio Segura Ortiz

Top image: (map) Topbanana
Second photo: (Antarctica, circular map) Kmusser ; CC – By – SA 3.0
Third photo: (bioscientist team) Jenny Blamey
Bottom photo: TEM of D. radiodurans acquired in the laboratory of Michael Daly, Uniformed Services University, Bethesda, MD, USA.

Paris Lavin, a microbiologist at the Chilean Antarctic Institute, studied 270 strains of actinomycete bacteria — the order that produces streptomycin antibiotics — isolated from seven lagoons on Antarctica’s King George Island, one of the South Shetland Islands. Because the organisms have been so remote, other bacteria are unlikely to have developed resistance to the antibiotic toxins that they produce, making them good candidates for new drugs.




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