Medical Research Council - London Institute of Medical Sciences

In 2017 we celebrated five years of bringing you beautiful imagery from biomedical science

Venomous Animals Week Urchin 'Urting
25 December 2014

Urchin 'Urting

Stepping on a sea urchin is very painful. I did it once (Ibiza, 1992) and a good-natured waiter poured vinegar on my heel to take away the pain. I assumed it was just the needle-like spines that hurt. But now – thanks to a team of scientists in Brazil looking into the toxins of Echinometra lucunter (pictured) – I see I was wrong. The researchers found that an enzyme called cathepsin B/X present in the urchin’s spines causes a painful inflammatory response in humans. Not only that, they discovered that this enzyme is also involved in regenerating the urchin’s spines, a hard matrix of calcium and magnesium carbonate, when broken. So there you go, this unforgiving enzyme that provides the urchin with a double whammy: reducing me to tears as a toxin while enabling the urchin to rearm and wait for the next unsuspecting holidaymaker.

Written by Nick Kennedy

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