Science News

"G. coli": bacteria thrive in hypergravity

Thu, 28th Apr 2011

Chris Smith

Bacteria can survive accelerations of 400,000g, making it highly likely that Bacterial Pelletbugs could survive an interplanetary crash-landing aboard an asteroid, or even flourish on high-gravity massive planets, new research has revealed.

Previously, scientists have investigated the behaviour of bacteria under conditions of microgravity - usually in space - which has been show to boost bacterial growth rates, alter the patterns of genes that are expressed and also reduce the production of antibiotic molecules made by some microbial family members. But only a handful of studies have so far explored the reverse situation: exposure to high-g conditions.

Now though, thanks to Japan Agency for Marine-Earth Science-based researcher Shigeru Deguchi and his colleagues, this work has been done. Publishing their findings in PNAS, the team incubated a selection of microbes, including the bacterial species E. coli, in an ultracentrifuge to simulate gravitational accelerations of up to 403,000 times that felt at the Earth's surface.

Surprisingly, despite the extreme conditions, the bugs grew, albeit more slowly than they would do normally. And examining the resulting cells under the microscope revealed that they were structurally intact and resembled control bugs grown under more ideal conditions, despite the 126.5 megapascal pressure they would have felt.

The researchers also modelled how the distribution of molecules would be affected inside the bacteria under the high-g conditions. For the majority of modest-sized molecules, they found, the effect would be negligible with a less than 9% difference in concentration between one end of the cell and the other.

These results, say the team, suggest that, at one thousandth of a millimetre across, bacterial cells are small enough that irreversible deformation due to gravity is not significant to impact on their viability.

From a practical point of view, this suggests that altering the accelerative environment in which bacteria are grown - such as in fermenters - could be used to manipulate the metabolic profile of the cells, for instance to boost antibiotic or drug production in biotechnology settings.

But an even-more tantilising conclusion the researchers draw, however, is that since the deceleration associated with an asteroid impact would be in the order of 300,000g, and this is well within the survival-range for the bacteria studied in this set of experiments, the prospect for panspermia - the interplanetary transit of life aboard celestial bodies - becomes much more plausible...

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It's possible, even probable that some did but not all bacteria arrived that way. Some evolved with life here. Farcanal, Fri, 29th Apr 2011

If any
If any bacteria arrived from space...  and were viable, then they would likely be the ancestors of all bacteria, and all life on Earth.

There is just too much similarity in DNA, RNA, Protein, and other structures for bacteria to have originated from two different independent sources.  Even Eukaryotes have much in common with Prokaryotes. 

However, having bacteria or spores travel through space on a meteorite, land on earth, and then flourish still has many issues.

Survive the impact or supernova that sent them into space
Survive in the icy-hot of space near a star with the side of an asteroid facing the sun reaching hundreds of degrees, while the side away from the sun is frozen.
Survive in the frigid space away from a star, potentially for thousands or millions of years, likely in a frozen state
Endure the Vacuum of Space
Endure Cosmic Rays, as well as radioactive decay and DNA degradation
Endure very hot atmospheric entry
Impact the planet with the force of an atomic bomb
Adapt to local food sources (of inorganic origin at the time before life)

On the positive side, many bacteria form spores which are quite inert, and designed to survive hostile environments.

It is a tall order for bacteria to survive in space and seed Earth.  But the evolution of the first living organism is also a very complex task.

Earth itself would be formed by the accretion of space debris.  And, during the heavy bombardment phase billions of years ago, the planet would have been hit by as many asteroid impacts as the moon.  So, even if it was only a 1 in a billion chance that bacteria would have survived to seed Earth.  Perhaps that would be enough. CliffordK, Fri, 29th Apr 2011

when i read the title of this thread i thought "que x-files theme tune" but i belive life started as a primordial soup but whether that came from space... who knows tangoblue, Fri, 3rd Jun 2011


That is a point...

Perhaps "life" could have been transferred to Earth without living organisms, but rather as a group of amino acids and nucleotides derived from living organisms elsewhere. 

If crude oil and coal are thought to be derived from living organisms, then do amino acids and nucleotides persist?

Here is an abstract to an article that seem to indicate that amino acids can be isolated from coal.

http://www.sciencedirect.com/science/article/pii/0016236181900338

Other studies have indicated that proteins can be isolated from demineralized fossils that are millions of years old.

And, thus one can conclude that the basic building blocks of life are very durable, and perhaps could survive a cataclysm and transfer to Earth.  If this was the case, then we should be able to find primordial amino acids on Mars. CliffordK, Sat, 4th Jun 2011

Anyone here fast asking God to show them He is real? I did it, nothing happened, moved on, still kept asking, not quitting and Jesus came to me, showed me the 4th dimension, or rather a few realms in it.... amazing stuff, God made the earth and all that is in it, to your very smile and attitude, ask for the Living Water from Jesus, meaning it, knowing He is real and waiting for a vision at nights and soon you will meet your maker. Peace. PS I hate organized religion I can send you details on how to break through for real to God and different dimensions, email me. Alex, Fri, 11th Oct 2013

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