Could a microbe be key to eternal youth?

London: Scientists have discovered a microbe that stays young forever by rejuvenating every time it reproduces, a finding that provides fundamental insights into the mechanisms of ageing.

An international team involving researchers from the University of Bristol and the Max-Planck Institute for Molecular Cell Biology and Genetics in Germany has found that a common species of yeast microbe has evolved to stay young.

The organism could potentially serve as a model of certain non-ageing types of cells in humans, researchers said.

The team has shown that, unlike other species, the yeast microbe called S pombe, is immune to ageing when it is reproducing and under favourable growth conditions.

In general, even symmetrically diving microbes, do not split into two exactly identical halves.

Detailed investigations revealed that there are mechanisms in place that ensure that one half gets older, often defective, cell material, whereas the other half is equipped with new fully-functional material.

So like humans microbes, in a sense, produce offspring that is younger than the parent.

 However, ageing is not inevitable for the common yeast, S pombe. Researchers found that this microbe is immune to ageing under certain conditions.

When the yeast is treated well, it reproduces by splitting into two halves that both inherit their fair share of old cell material.

"However, as both cells get only half of the damaged material, they are both younger than before," said Iva Tolic, the lead investigator on the project.

At least in a sense, the yeast is rejuvenated a bit, every time it reproduces, Tolic said.

 Unlike other species S pombe can escape ageing as long as it keeps dividing fast enough.

To test what happens to the microbe when it is treated badly, the researchers exposed the yeast to heat, ultraviolet radiation, and damaging chemicals, which slowed its growth to a point where the microbes could not divide fast enough to stay young.

Once subjected to these negative influences the yeast cells started splitting into a younger and an older half just like other cells. While the older cells eventually died, their offspring survived long enough to reproduce even in the harsh environments.

The findings are published in the journal Current Biology.