Posts about extremophile

Changing Life as We Know It

Update: Independent researchers find no evidence for arsenic life in Mono Lake

NASA has made a discovery that changes our understanding of the very makeup of life itself on earth. I think my favorite scientific discipline name is astrobiology. NASA pursues a great deal of this research not just out in space but also looking at earth based life. Their astrobiology research has changed the fundamental knowledge about what comprises all known life on Earth.

photo of Felisa Wolfe-Simon

Felisa Wolfe-Simon processing mud from Mono Lake to inoculate media to grow microbes on arsenic.

Carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur are the six basic building blocks of all known forms of life on Earth. Phosphorus is part of the chemical backbone of DNA and RNA, the structures that carry genetic instructions for life, and is considered an essential element for all living cells.

Phosphorus is a central component of the energy-carrying molecule in all cells (adenosine triphosphate) and also the phospholipids that form all cell membranes. Arsenic, which is chemically similar to phosphorus, is poisonous for most life on Earth. Arsenic disrupts metabolic pathways because chemically it behaves similarly to phosphate.

Researchers conducting tests in the harsh, but beautiful (see photo), environment of Mono Lake in California have discovered the first known microorganism on Earth able to thrive and reproduce using the toxic chemical arsenic. The microorganism substitutes arsenic for phosphorus in its cell components.

“The definition of life has just expanded,” said Ed Weiler, NASA’s associate administrator for the Science Mission Directorate. “As we pursue our efforts to seek signs of life in the solar system, we have to think more broadly, more diversely and consider life as we do not know it.” This finding of an alternative biochemistry makeup will alter biology textbooks and expand the scope of the search for life beyond Earth.

In science such huge breakthroughs are not just excepted without debate, however, which is wise.

Thriving on Arsenic:

In other words, every experiment Wolfe-Simon performed pointed to the same conclusion: GFAJ-1 can substitute arsenic for phosphorus in its DNA. “I really have no idea what another explanation would be,” Wolfe-Simon says.

But Steven Benner, a distinguished fellow at the Foundation for Applied Molecular Evolution in Gainesville, FL, remains skeptical. If you “replace all the phosphates by arsenates,” in the backbone of DNA, he says, “every bond in that chain is going to hydrolyze [react with water and fall apart] with a half-life on the order of minutes, say 10 minutes.” So “if there is an arsenate equivalent of DNA in that bug, it has to be seriously stabilized” by some as-yet-unknown mechanism.

It is sure a great story if it is true though. Other scientists will examine more data and confirm or disprove the claims.

“We know that some microbes can breathe arsenic, but what we’ve found is a microbe doing something new — building parts of itself out of arsenic,” said Felisa Wolfe-Simon, a NASA Astrobiology Research Fellow in residence at the U.S. Geological Survey in Menlo Park, Calif., and the research team’s lead scientist. “If something here on Earth can do something so unexpected, what else can life do that we haven’t seen yet?”
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A single Liter of Seawater Can Hold More Than One Billion Microorganisms

Mat of microbes the size of Greece discovered on seafloor

mighty microbes, which constitute 50 to 90 percent of the oceans’ total biomass, according to newly released data.

These tiny creatures can join together to create some of the largest masses of life on the planet, and researchers working on the decade-long Census of Marine Life project found one such seafloor mat off the Pacific coast of South America that is roughly the size of Greece.

A single liter of seawater, once thought to contain about 100,000 microbes, can actually hold more than one billion microorganisms, the census scientists reported. But these small creatures don’t just live in the water column or on the seafloor. Large communities of microscopic animals have even been discovered more than one thousand meters beneath the seafloor. Some of these deep burrowers, such as loriciferans, are only a quarter of a millimeter long.

“Far from being a lifeless desert, the deep sea rivals such highly diverse ecosystems as tropical rainforests and coral reefs,”

Microbes help to turn atmospheric carbon dioxide into usable carbon, completing about 95 percent of all respiration in the Earth’s oceans…

Related: Iron-breathing Species Isolated in Antarctic for Millions of YearsLife Far Beneath the OceanLife Untouched by the Sun

Extremophile Hunter

NSF has begun publishing a new web magazine: Science Nation. The inaugural article is Extremophile Hunter

Astrobiologist Richard Hoover really goes to extremes to find living things that thrive where life would seem to be impossible–from the glaciers of the Alaskan Arctic to the ice sheets of Antarctica.

“It may be that when we ultimately get a chance to bring back samples of ice from the polar caps of Mars, we might find biology that looks just like Earth life and it might be that it originated on Earth and was carried to Mars,” said Hoover. “Of course, if it can happen that way, it could have happened the other way. So we may never know the ultimate answer to how did life originate.”

Some of the structures he has imaged from these meteorites are intriguing, bearing striking similarities to bacteria here on Earth. Could these be the fossilized remains of extraterrestial life?

“I am convinced that what I am finding in the carbonaceous meteorites are in many cases biological in nature, and I think they are indigenous and not terrestrial contaminants,” said Hoover.

It is a highly controversial interpretation. “We have for a long time thought that all life, as we know it, originated on Earth. And there isn’t any life anywhere else,” he said. “That’s an idea, it’s a hypothesis, it’s a totally unproven hypothesis.”

Related: TardigradesWhat is an Extremophile?Light-harvesting Bacterium Discovered in Yellowstone

Iron-breathing Species Isolated in Antarctic for Millions of Years

Graphic showing environment of Antarctic subglacial microbesGraphic of Blood Falls showing microbial community environment in the Antarctic by Zina Deretsky at NSF)

A reservoir of briny liquid buried deep beneath an Antarctic glacier supports hardy microbes that have lived in isolation for millions of years, researchers report this week. The discovery of life in a place where cold, darkness, and lack of oxygen would previously have led scientists to believe nothing could survive comes from a team led by researchers at Harvard University and Dartmouth College.

Despite their profound isolation, the microbes are remarkably similar to species found in modern marine environments, suggesting that the organisms now under the glacier are the remnants of a larger population that once occupied an open fjord or sea.

“It’s a bit like finding a forest that nobody has seen for 1.5 million years,” says Ann Pearson, Thomas D. Cabot Associate Professor of Earth and Planetary Sciences in Harvard’s Faculty of Arts and Sciences. “Intriguingly, the species living there are similar to contemporary organisms, and yet quite different — a result, no doubt, of having lived in such an inhospitable environment for so long.”

“This briny pond is a unique sort of time capsule from a period in Earth’s history,” says lead author Jill Mikucki, now a research associate in the Department of Earth Sciences at Dartmouth and visiting fellow at Dartmouth’s Dickey Center for International Understanding and its Institute of Arctic Studies. “I don’t know of any other environment quite like this on Earth.”

Chemical analysis of effluent from the inaccessible subglacial pool suggests that its inhabitants have eked out a living by breathing iron leached from bedrock with the help of a sulfur catalyst. Lacking any light to support photosynthesis, the microbes have presumably survived by feeding on the organic matter trapped with them when the massive Taylor Glacier sealed off their habitat an estimated 1.5 to 2 million years ago.
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Tardigrades

Tardigrades (commonly known as water bears) have eight legs and are their own phylum on the tree of life. Some can survive temperatures close to absolute zero, temperatures as high as 151 °C (303 °F), 1,000 times more radiation than any other animal, nearly a decade without water, and even the vacuum of space.

Related: Tardigrades, UNC Chapel HillTardigrades In Space (TARDIS)What is an Extremophile?Evolution, Methane, Jobs, Food and More

Tardigrades In Space (TARDIS)

Research showing that Tardigrades (Water Bears) can survive in space without protection has been in the news lately. There is a blog with a few posts from the research team (only from last year unfortunately): Tardigrades In Space (TARDIS). They chose not to publish the research in an open access fashion, unfortunately.

Tiny Critters Survive Space

These small, segmented animals not only survived a 12-day orbital expedition, some members of the community felled by solar radiation actually recovered upon their return to Earth.

“How these animals were capable of reviving their body … remains a mystery,” said lead researcher Ingemar Jönsson, with Sweden’s Kristianstad University, who writes about the discovery in this week’s issue of Current Biology.

Most of the 3,000 creatures not only survived, but they went on to reproduce once they came back to Earth. About 12 percent of the animals exposed to ultraviolet radiation revived after being put back in water, a puzzling find since researchers presume the sterilizing rays broke down the tardigrades’ DNA. “This type of radiation cuts the DNA strand effectively in most organisms”

Related: Bacteria Frozen for 8 Million Years In Polar Ice ResuscitatedWhat is an Extremophile?posts on extremophiles

Life After the Chernobyl Nuclear Accident

Silent Spring by Lauren Monaghan, Cosmos

Ever since, a 30 km ‘exclusion zone’ has existed around the contaminated site, accessible to those with special clearance only. It’s quite easy, then, to conjure an apocalyptic vision of the area; to imagine an eerily deserted wasteland, utterly devoid of life.

But the truth is quite the opposite. The exclusion zone is teeming with wildlife of all shapes and sizes, flourishing unhindered by human interference and seemingly unfazed by the ever-present radiation. Most remarkable, however, is not the life buzzing around the site, but what’s blooming inside the perilous depths of the reactor.

Sitting at the centre of the exclusion zone, the damaged reactor unit is encased in a steel and cement sarcophagus. It’s a deathly tomb that plays host to about 200 tonnes of melted radioactive fuel, and is swarming with radioactive dust.

But it’s also the abode of some very hardy fungi which researchers believe aren’t just tolerating the severe radiation, but actually harnessing its energy to thrive.

“Our findings suggest that [the fungi] can capture the energy from radiation and transform it into other forms of energy that can be used for growth,” said microbiologist Arturo Casadevall from the Albert Einstein College of Medicine at Yeshiva University in New York, USA.

Taken together, the researchers think their results do indeed hint that fungi can live off ionising radiation, harnessing its energy through melanin to somehow generate a new form of biologically usable growing power.

If they’re right, then this is powerful stuff, said fungal biologist Dee Carter from the University of Sydney. The results will challenge fundamental assumptions we have about the very nature of fungi, she said.

It also raises the possibility that fungi might be using melanin to secretly harvest visible and ultraviolet light for growth, adds Casadevall. If confirmed, this will further complicate our understanding of these sneaky organisms and their role in ecosystems.

Pretty amazing stuff. It really is great all that nature gives us to study and learn about using science.

Related: Radiation Tolerant BacteriaNot Too Toxic for LifeBacterium Living with High Level RadiationWhat is an Extremophile?

Bacteria Frozen for 8 Million Years In Polar Ice Resuscitated

Eight-million-year-old bug is alive and growing

Kay Bidle of Rutgers University in New Jersey, US, and his colleagues extracted DNA and bacteria from ice found between 3 and 5 metres beneath the surface of a glacier in the Beacon and Mullins valleys of Antarctica. The ice gets older as it flows down the valleys and the researchers took five samples that were between 100,000 and 8 million years old.

They then attempted to resuscitate the organisms in the oldest and the youngest samples. “We tried to grow them in media, and the young stuff grew really fast. We could plate them and isolate colonies,” says Bidle. The cultures grown from organisms found in the 100,000-year-old ice doubled in size every 7 days on average.

Whereas the young ice contained a variety of microorganisms, the researchers found only one type of bacterium in the 8-million-year-old sample. It also grew in the laboratory but much more slowly, doubling only every 70 days.

Related: What is an Extremophile?

What is an Extremophile?

What is an Extremophile?

An extremophile is an organism that thrives under “extreme” conditions. The term frequently refers to prokaryotes and is sometimes used interchangeably with Archaea.

The term extremophile is relatively anthropocentric. We judge habitats based on what would be considered “extreme” for human existence. Many organisms, for example, consider oxygen to be poisonous.

The site includes interesting photos and details on all sorts of extremophiles: Anaerobe (don’t require oxygen) – Endolith (live inside rocks) – Thermophile (enjoy over 40 °C).

Related: Types of MicrobesLife Untouched by the Sun

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