Scientists have identified a "blue wave of death" that spreads from cell to cell until the entire organism has met their demise.

At the time of death a chemical reaction breaks down cell components causing a build-up of molecular debris, a University College London press release reported.

Researcher already understood this process, what they didn't know was how the reaction spread throughout the body.

The UCL team studied worms under a microscope at their time of death and noticed a "wave of blue fluorescence travelling through the gut."

"We've identified a chemical pathway of self-destruction that propagates cell death in worms, which we see as this glowing blue fluorescence travelling through the body. It's like a blue grim reaper, tracking death as it spreads throughout the organism until all life is extinguished," Professor David Gems, of the UCL Institute of Health Ageing and leader of the study, said.

"We found that when we blocked this pathway, we could delay death induced by a stress such as infection, but we couldn't slow death from old-age. This suggests that aging causes death by a number of processes acting in parallel," he said.

Researchers previously thought a substance called lipofuscin (which is associated with a similar light and color) was responsible for the blue fluorescence. Lipofuscin was has also been linked to aging and cell damage. This new study found the wave was actually caused by a molecule called anthranilic acid.

The process is consistent with previously observed chemical reactions in mammals, meaning studying the worms could lead to a better understanding of human death.

"Together the findings cast doubt on the theory that aging is simply a consequence of an accumulation of molecular damage. We need to focus on the biological events that occur during aging and death to properly understand how we might be able to interrupt these processes," Professor Gems said.

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