Wave of blue fluorescence reveals pathway of death in worms

Ghostly blue fluorescence spreads through a dying nematode worm, revealing the passage of death through its body. Time = 0 is the point of ultimate death. Credit: Cassandra Coburn

The final biological events in the life of a worm are described today, revealing how death spreads like a wave from cell to cell until the whole organism is dead.

When individual cells die, it triggers a chemical chain reaction that leads to the breakdown of cell components and a build-up of molecular debris. The molecular mechanisms of this are reasonably well understood at a but we know much less about how death spreads throughout an organism at the end of its life.

In worms, the spread of death can be seen easily under a microscope as a wave of blue fluorescence travelling through the gut of the worm. The study, led by researchers funded by the Wellcome Trust and BBSRC, reveals that this fluorescence is caused by a cell death pathway called and its spread throughout the organism is dependent on calcium signalling.

Professor David Gems from the Institute of Health Ageing at UCL, who led the study, explains: "We've identified a 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.

"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-. This suggests that ageing causes death by a number of processes acting in parallel."

The mechanisms involved are similar to those that are active in , confirming that the worm can provide a useful model to understand cell death in people.

The study, published online today in PLoS Biology, also links the mechanisms of to the appearance of the blue fluorescence.

The source of the blue fluorescence was previously thought to be a substance called lipofuscin, which emits light of a similar colour and has been linked to ageing because it accumulates with increasing molecular damage. However, the new findings implicate another molecule called anthranilic acid as the source of the blue hue and show that lipofuscin is not involved.

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

More information: PLoS Biol 11(7): e1001613. doi:10.1371/journal.pbio.1001613

Related Stories

Molecular switch controls the destiny of self-eating cells

Jul 17, 2013

The study is the result of a collaboration of scientists at Karolinska Institutet in Sweden, University of Michigan, and University of California San Diego, USA, who were interested in finding out whether autophagy can be ...

Recommended for you

Growing a blood vessel in a week

Oct 24, 2014

The technology for creating new tissues from stem cells has taken a giant leap forward. Three tablespoons of blood are all that is needed to grow a brand new blood vessel in just seven days. This is shown ...

Testing time for stem cells

Oct 24, 2014

DefiniGEN is one of the first commercial opportunities to arise from Cambridge's expertise in stem cell research. Here, we look at some of the fundamental research that enables it to supply liver and pancreatic ...

Team finds key signaling pathway in cause of preeclampsia

Oct 23, 2014

A team of researchers led by a Wayne State University School of Medicine associate professor of obstetrics and gynecology has published findings that provide novel insight into the cause of preeclampsia, the leading cause ...

Rapid test to diagnose severe sepsis

Oct 23, 2014

A new test, developed by University of British Columbia researchers, could help physicians predict within an hour if a patient will develop severe sepsis so they can begin treatment immediately.

User comments