Wednesday, April 27, 2011

Bacteria Grow Under 400,000 Times Earth's Gravity

Bacteria grown under normal gravity for four hours (left) and at 134,425 Gs of gravity for 48 hours (right).Proving that you don't have to be big to be tough, some microbes can survive gravity more than 400,000 times that felt on Earth, a new study says.

Most humans, by contrast, can tolerate forces equal to about three to five times Earth's surface gravity (g) before losing consciousness.

The extreme "hypergravity" of 400,000 g is usually found only in cosmic environments, such as on very massive stars or in the shock waves of supernovas, said study leader Shigeru Deguchi, a biologist at the Japan Agency for Marine-Earth Science and Technology.

Deguchi and his team were able to replicate hypergravity on Earth using a machine called an ultracentrifuge.

The scientists rapidly spun four species of bacteria—including the common human gut microbe Escherichia coli—to create increasingly intense gravity conditions.

The bacteria clumped together into pellets as the gravity increased, but their forced closeness didn't seem to deter growth: All four species multiplied normally under thousands to tens of thousands of times Earth's gravity.

Two of the species—E. coli and Paracoccus denitrificans, a common soil bacteria—grew under the strain of 403,627 g. ...

via Bacteria Grow Under 400,000 Times Earth's Gravity.

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