Researchers from Japan have discovered how an enzyme in the laboratory roundworm Caenorhabditis elegans influences the rate at which the creature ages.

The key to the process is oxidative stress - the damage caused to cells by destructive oxygen atoms called free radicals.

Mutated gene

A mutation in one of the worm's genes had previously been shown to trigger increased sensitivity to high oxygen concentrations, and a shorter life span.

Now scientists have shown that the mutant gene variant, known as mev-1, produces part of an enzyme involved in electron transport in mitochondria, the engine of cells.

The mitochondrial electron transport pathway is essential to how cells move energy around, but is sensitive to damage from oxidising agents.

Cellular ageing

This damage leads to symptoms associated with cellular ageing. The scientists led by Naoaki Ishii from the Tokai University School of Medicine, suggest that the enzyme affected by mev-1 governs the rate of ageing by modulating the cell's response to oxidative stress.

A mev-1 mutation resulted in a defective enzyme, which in turn caused the ageing rate to increase.

The scientists pointed out that in humans certain muscle and neurodegenerative diseases, as well as premature ageing, were mitochondrially related.