Posts Tagged ‘Life’

by Bec Crew

Strange microbes have been found inside the massive, subterranean crystals of Mexico’s Naica Mine, and researchers suspect they’ve been living there for up to 50,000 years.

The ancient creatures appear to have been dormant for thousands of years, surviving in tiny pockets of liquid within the crystal structures. Now, scientists have managed to extract them – and wake them up.

“These organisms are so extraordinary,” astrobiologist Penelope Boston, director of the NASA Astrobiology Institute, said on Friday at the annual meeting of the American Association for the Advancement of Science (AAAS) in Boston.

The Cave of Crystals in Mexico’s Naica Mine might look incredibly beautiful, but it’s one of the most inhospitable places on Earth, with temperatures ranging from 45 to 65°C (113 to 149°F), and humidity levels hitting more than 99 percent.

Not only are temperatures hellishly high, but the environment is also oppressively acidic, and confined to pitch-black darkness some 300 metres (1,000 feet) below the surface.

In lieu of any sunlight, microbes inside the cave can’t photosynthesise – instead, they perform chemosynthesis using minerals like iron and sulphur in the giant gypsum crystals, some of which stretch 11 metres (36 feet) long, and have been dated to half a million years old.

Researchers have previously found life living inside the walls of the cavern and nearby the crystals – a 2013 expedition to Naica reported the discovery of creatures thriving in the hot, saline springs of the complex cave system.

But when Boston and her team extracted liquid from the tiny gaps inside the crystals and sent them off to be analysed, they realised that not only was there life inside, but it was unlike anything they’d seen in the scientific record.

They suspect the creatures had been living inside their crystal castles for somewhere between 10,000 and 50,000 years, and while their bodies had mostly shut down, they were still very much alive.

“Other people have made longer-term claims for the antiquity of organisms that were still alive, but in this case these organisms are all very extraordinary – they are not very closely related to anything in the known genetic databases,” Boston told Jonathan Amos at BBC News.

What’s perhaps most extraordinary about the find is that the researchers were able to ‘revive’ some of the microbes, and grow cultures from them in the lab.

“Much to my surprise we got things to grow,” Boston told Sarah Knapton at The Telegraph. “It was laborious. We lost some of them – that’s just the game. They’ve got needs we can’t fulfil.”

At this point, we should be clear that the discovery has yet to be published in a peer-reviewed journal, so until other scientists have had a chance to examine the methodology and findings, we can’t consider the discovery be definitive just yet.

The team will also need to convince the scientific community that the findings aren’t the result of contamination – these microbes are invisible to the naked eye, which means it’s possible that they attached themselves to the drilling equipment and made it look like they came from inside the crystals.

“I think that the presence of microbes trapped within fluid inclusions in Naica crystals is in principle possible,” Purificación López-García from the French National Centre for Scientific Research, who was part of the 2013 study that found life in the cave springs, told National Geographic.

“[But] contamination during drilling with microorganisms attached to the surface of these crystals or living in tiny fractures constitutes a very serious risk,” she says. I am very skeptical about the veracity of this finding until I see the evidence.”

That said, microbiologist Brent Christner from the University of Florida in Gainesville, who was also not involved in the research, thinks the claim isn’t as far-fetched as López-García is making it out to be, based on what previous studies have managed with similarly ancient microbes.

“[R]eviving microbes from samples of 10,000 to 50,000 years is not that outlandish based on previous reports of microbial resuscitations in geological materials hundreds of thousands to millions of years old,” he told National Geographic.

For their part, Boston and her team say they took every precaution to make sure their gear was sterilised, and cite the fact that the creatures they found inside the crystals were similar, but not identical to those living elsewhere in the cave as evidence to support their claims.

“We have also done genetic work and cultured the cave organisms that are alive now and exposed, and we see that some of those microbes are similar but not identical to those in the fluid inclusions,” she said.

Only time will tell if the results will bear out once they’re published for all to see, but if they are confirmed, it’s just further proof of the incredible hardiness of life on Earth, and points to what’s possible out there in the extreme conditions of space.

By Aviva Rutkin

Nicknamed Earth’s evil twin, Venus seems like everything our planet is not: scorching hot, dried out and covered in toxic clouds.

But a mere one or two billion years ago, these two wayward siblings might have been more alike. New computer simulations suggest that early Venus might have looked a lot like our home planet – and it might even have been habitable.

“It’s one of the big mysteries about Venus. How did it get so different from Earth when it seems likely to have started so similarly?” says David Grinspoon at the Planetary Science Institute in Tucson, Arizona. “The question becomes richer when you consider astrobiology, the possibility that Venus and Earth were very similar during the time of the origin of life on Earth.”

Grinspoon and his colleagues aren’t the first to imagine that Venus was once hospitable. It’s similar to Earth in size and density, and the fact that the two planets formed so close together suggests that they’re made of the same bulk materials. Venus also has an unusually high ratio of deuterium to hydrogen atoms, a sign that it once housed a substantial amount of water, mysteriously lost over time.

Venus, but snowy
To simulate early Venus, the researchers turned to a model of environmental conditions often used to study climate change here on Earth. They created four versions for Venus, each varying slightly in details such as the amount of energy the planet received from the sun, or the length of a Venusian day. Where information was scant about Venus’s climate, the team filled in educated guesses. They also added a shallow ocean, 10 per cent the volume of Earth’s ocean, covering about 60 per cent of the planet’s surface.

Looking at how each version might have evolved over time, the researchers say they were encouraged to believe that the planet might have looked much like an early Earth, and remained habitable for a substantial portion of its lifetime. The most promising of the four Venuses enjoyed moderate temperatures, thick cloud cover and even the occasional light snowfall.

Could life have emerged on this early Venus? If it did, it’s certainly no more, thanks to the oceans later boiling away and volcanoes drastically reshaping the landscape around 715 million years ago. But the team is not ruling it out.

“There’s great uncertainties in understanding Earth, not only its climate history but the history of how life began,” says Michael Way at the NASA Goddard Institute for Space Studies in New York City. If it began in oceans on Earth – a theory we’ve yet to confirm – the same could be true on a waterlogged Venus. “There’s no reason that life on this world would not have existed in these oceans. But that’s about all you can say.”

Alternative histories
“Both planets probably enjoyed warm liquid water oceans in contact with rock and with organic molecules undergoing chemical evolution in those oceans,” says Grinspoon. “As far as we understand at present, those are the requirements for the origin of life.”

To bolster their findings, the team suggests a future mission to Venus should look out for signs of water-related erosion near the equator, which would provide evidence for the oceans detailed in their simulation. Such signs have already been detected by missions at Mars. NASA is currently weighing up two potential Venus projects, although neither has been confirmed. One mission would drop a probe through the clouds down to the surface, while another would orbit around the planet and image its surface.

The researchers would also like to run simulations of further alternative pasts for Venus – perhaps one where it was a desert world, or submerged in as much water as Earth, to find out which scenario is most likely to lead to the Venus we see today.

The study could also aid astronomers in their search for exoplanets, says James Kasting at Pennsylvania State University. If Venus might have once been habitable, then it suggests that other planets close to their stars might be, too. “If you make the habitable zone really wide, that raises the probability of finding an Earth.”


By Jennifer Frazer

In addition to irritatingly lodging themselves everywhere from shower grout to the Russian space station Mir, fungi that live inside rocks in Antarctica have managed to survive a year and half in low-Earth orbit under punishing Mars-like conditions, scientists recently reported in the journal Astrobiology. A few of them even managed to cap their year in Mars-like space by reproducing.

Why were they subjected to such an ordeal? Scientists have concluded over the past decade that Mars (which like Earth is about four and a half billion years old) supported water for long periods during its first billion years, and they wonder if life that may have evolved during that time may remain on the planet in fossilized or even fresh condition. The climate back then was more temperate than today, featuring a thicker atmosphere and a more forgiving and moist climate.

But how do you search for that life? Using life that exists in what they believe is this planet’s closest analogue, a team of scientists from Europe and the United States hoped to identify the kind of biosignatures that might prove useful in such a search, while also seeing if the Earthly life forms might be capable of withstanding current Mars-like conditions.

Which is to say, not nice.

The temperature on Mars fluctuates wildly on a daily basis. The Mars Science Laboratory rover has measured daily swings of up to 80°C (that’s 144°F), veering from -70°C(-94°F) at night to 10°C(50°F) at Martian high noon. If you can survive that, you also have to get past the super-intense ultraviolet radiation, an atmosphere of 95% carbon dioxide (the effect of which on humans was vividly illustrated at the end of Total Recall), a pressure of 600 to 900 Pascals (Earth: 101,325 Pascals), and cosmic radiation at a dose of about .2mGy/day (Earth: .001 mGy/day). I don’t know about you, but Mars is not my first vacation choice.

And it’s probably not Cryomyces antarcticus’s either, in spite of the extreme place it calls home. Cryomyces antarcticus and its relative Cryomyces minteri – the two fungi tested independently in this study — are members of a group called black fungi or black yeast for their heavily pigmented hulls that allow them to withstand a wide variety environmental stresses. Members of the group somewhat notoriously turned up a few years ago in a study that found two species of the group commonly live inside dishwashers in people’s homes (they were opportunistic human pathogns, but most humans are immune to them). But most of these fungi live quietly in the most extreme environments on earth.

The particular black fungi used in this experiment, generally considered the toughest on the planet, live in tiny tunnels of their own creation inside Antarctic rocks. This is apparently the only place they can grow without being annihilated by the crushing climate and blistering ultraviolet radiation of Antarctica. Antarctica also happens to be the place on Earth most similar – although still not particularly similar, as you have seen — to our friendly neighborhood Red Planet. This endurance has made both black fungi and their neighbors the lichens popular test pilots for Mars-like conditions on the international space station.

For example, lichen-forming fungi that create the common and beautiful orange Xanthoria elegans and also Acarospora made the same trip to the ISS previously, in a European module of the International Space Station called EXPOSE-E. Both survived the experience, and Acarospora even managed to reproduce.

But this seems to be the first time a non-lichen forming fungus has received the ISS treatment.

These particular two fungi – Cryomyces antarcticus and Cryomyces minteri – were collected from the McMurdo Dry Valleys of Antarctica in Southern Victoria Land, supposedly the most Mars-like place on Earth. They were isolated from dry sandstone onto a plate of fungus food called malt extract agar. This gelatinous disc was then dried along with the fungus living on it inside a dessicator, and sent into space like that.

Each colony was about 1mm in diameter, and each yeast cell in it was 10 micrometers in size. Like most black yeast/fungi, they have a dark outer wall.

The scientists also tested an entire community of “cryptoendolithic” organisms – those that live secretly inside rocks, including not just fungi but also rock-dwelling blue-green algae – by testing whole fragments of rocks collected on Battleship Promontory in Southern Victoria Land, Antarctica. The various organisms live in bands of varying color and depth within 1 centimeter of the rock surface.

The fungi were launched into space in February 2008 and returned to Earth on September 12, 2009. During that time they were placed in a bath of gasses as similar as possible to the atmosphere of Mars and exposed to simulated full Martian UV radiation, one-thousandth Martian UV, or kept in the dark. They also endured the cosmic background radiation of space and temperature swings between -21.7°C and 42.9°C – much warmer than Mars, but the best that could be done. Control samples remained in the dark on Earth.

Once back on Earth, the colonies and rock samples were rehydrated. Their appearance had not changed during their voyage. They were then tested for viability by diluting them in water and plating the resulting solution to see how many new colonies formed. They also estimated the percentage of cells with undamaged cell membranes by using a chemical that can only penetrate damaged cell membranes.

The scientists found that the black yeast’s ability to form new colonies was severely impaired by its time on “Mars”, but it was not zero. When kept in the dark on the ISS, about 1.5% of C. antarcticus was able to form colonies post-exposure, while only .08% of C. minteri could. Surprisingly, those exposed to .1% of Mars UV did better, with 4-5 times more surviving: just over 8% for C. antarcticus and 2% for C. minteri. Perhaps the weak radiation stimulated mutations or stress-response proteins that might have helped the fungi somehow.

With the full force of Martian radiation, the survival rates were about the same as for those samples kept in the dark, which is to say, nearly nil. By comparison, about 46% of control C. antarcticus samples kept in the dark back on Earth yielded colony forming units, while only about 17% of C. minteri did. Not super high rates, but still much higher than their space-faring comrades.

On the other hand, the percentage of cells with intact cell membranes was apparently much higher than the number that could reproduce. 65% of C. antarcticus cells remained intact regardless of UV exposure, while C. minteri’s survival rates fluctuated between 18 and 50%, again doing better with UV exposure than in the dark. Colonized rock communities yielded the highest percentage of intact cells of any samples when kept in the dark – around 75%, but some of the lowest when exposed to solar UV, with just 10-18 % surviving intact.

What explains this apparent survival discrepancy between being alive and being able to reproduce? It may be that the reproductive apparati of the fungi are more sensitive to cosmic radiation than their cell membranes and walls, the authors suggest.

The authors’ results also suggest to them that DNA is the biomolecule of choice to use to search for life on Mars, as it, like the cell membranes, survived largely intact even in cells that could no longer reproduce.

Although Mars-based life may not use DNA genetic material, then again, it just might. It certainly seems to have worked well for us here on Earth.

Even though few of the fungi exposed to Mars-like conditions survived well enough to reproduce, in all cases, at least a fraction did. Perhaps that is the material thing. A similar previous experiment showed one green alga, Stichococcus, and one fungus, Acarospora were able to reproduce after a very similar trip on the space station. Another experiment with the bacterium Bacillus subtilis found that up to 20% of their spores were able to germinate and grow after Mars-like exposure. Theoretically, it only takes one or two to hang on and adapt to these conditions to found a whole lineage of Mars-tolerant life (the major reason, by the way, for NASA’s Planetary Protection Program).

On the other hand, some have suggested that long-term survival of Earthly life is impossible on Mars. Given the extremely low reproductive ability after just 1.5 years, this study did nothing to undermine that idea either.

But all of our studies have tested life that evolved on Earth. What about life that evolved on Mars? There’s just no telling how similar or dissimilar such creatures — supposing they exist or ever existed – might be.

Instruments on the Rosetta spacecraft have detected compounds critical to life, including the amino acid glycine and the element phosphorus, in the shroud of gases surrounding Comet 67P/Churyumov-Gerasimenko

For the first time, scientists have directly detected a crucial amino acid and a rich selection of organic molecules in the dusty atmosphere of a comet, further bolstering the hypothesis that these icy objects delivered some of life’s ingredients to Earth.

The amino acid glycine, along with some of its precursor organic molecules and the essential element phosphorus, were spotted in the cloud of gas and dust surrounding Comet 67P/Churyumov-Gerasimenko by the Rosetta spacecraft, which has been orbiting the comet since 2014. While glycine had previously been extracted from cometary dust samples that were brought to Earth by NASA’s Stardust mission, this is the first time that the compound has been detected in space, naturally vaporized.

The discovery of those building blocks around a comet supports the idea that comets could have played an essential role in the development of life on early Earth, researchers said.

“With all the organics, amino acid and phosphorus, we can say that the comet really contains everything to produce life — except energy,” said Kathrin Altwegg of the University of Bern in Switzerland, the principal investigator for the Rosetta mission’s ROSINA instrument.

“Energy is completely missing on the comet, so on the comet you cannot form life,” Altwegg told “But once you have the comet in a warm place — let’s say it drops into the ocean — then these molecules get free, they get mobile, they can react, and maybe that’s how life starts.”

Getting a glimpse

Glycine, one of the simplest amino acids, is usually bound up as a solid, which means it’s difficult to detect from afar, Altwegg said.

While scientists have searched for glycine through telescopes in star-forming regions of the sky, the newly reported detection marks the first sighting of the compound in space. In this case, the orbiting Rosetta was close enough to pick up the glycine released by the comet’s dust grains as they heated up in the sun.

The study is a powerful confirmation of earlier, earth-bound detections of life’s building blocks in comet and meteor material.

“We know the Earth was pretty heavily bombarded both with asteroidal material and cometary material,” said Michael A’Hearn, a comet researcher at the University of Maryland who was not involved in the new study.

“There have been various claims of amino acids in meteorites, but all of them have suffered from this problem of contamination on Earth. The Stardust [samples] — which are from a comet, not an asteroid — are probably the least susceptible to the terrestrial contamination problem, but even there the problem is severe,” A’Hearn told “I think they [Stardust] really did have glycine, but this is a much cleaner detection in many ways.”

Cooking up life
Amino acids form the basis of proteins, which are complexly folded molecules that are critical to life on Earth. Altwegg’s team searched for other amino acids around the comet as well, but located only glycine — the only one that can form without liquid water (as in the frigid reaches of space).

The glycine probably didn’t form on the comet itself, Altwegg said, but rather in the broad stretches of dust and debris that made up the solar system before planetary bodies formed.

“The solar system was made out of material which formed in a disk, in a solar nebula,” Altwegg said. “In these clouds, it’s pretty cold, so the chemistry you do there is catalytic chemistry on the dust surfaces. And these very small dust grains [1 micron in size] are very good to lead to organic chemistry. This is also done in the lab.” Earth itself was far too hot for similar delicate amino acids to survive its formation, Altwegg said; only the smallest solar system bodies stayed cold.

So glycine formed during that time could have provided a boost to newly forming life if it was delivered to Earth by comets.

“It’s not that it couldn’t have formed on Earth — it certainly could — it’s just that it didn’t have to,” A’Hearn said. “Basically, the Earth got a head start.”

Other, more complex amino acids require liquid water, and so would have likely formed on Earth itself, Altwegg said. This idea is supported by the fact that Rosetta has not identified any amino acids other than glycine near Comet 67P.

Phosphorus is also vital to life as we know it. Among other things, the element is a key constituent of DNA and adenosine triphosphate (ATP), a molecule that stores the chemical energy used by cells.

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Thanks to Kebmodee for bringing this to the attention of the It’s Interesting community.