An artist's impression of the process of apoptosis or programmed cell death - I think that's a phagocyte or white blood cell on the right, cleaning up the mess
Recently a reader of the newspaper for which I work wrote to ask why on earth we always publish such ridiculous artist’s impressions every time there is an outbreak of a disease (the latest was Legionnaires’ disease).
I explained that we needed an illustration of some sort and couldn’t always take a photograph of a victim. The artist’s impression cost us nothing as it was in our archive already – and anyway the images were pretty and colourful.
I am reminded of this as I illustrate one of my “favourite words” – APOPTOSIS. It’s a word I first heard spoken by my old Biology master, when describing how tadpoles turn into frogs and toads.
Apoptosis means cell death – but don’t panic, it’s all programmed naturally into multicellular organisms. It’s the body’s usual method of getting rid of damaged or unwanted cells. The mess is then cleaned up by white blood cells (another great words – PHAGOCYTES).
In the embryo apoptosis is important for sculpting tissue and organ structure – without it we would all have webbed hands and feet, for example. It also happens in adult cells when a tissue needs to be reshaped.
Cells go “pop” (as I like to think of it) when they receive a signal, from inside or outside the cell, which stimulates suicide receptors in the cell’s external membrane. When these are internal signals, they are caused by the interaction of proteins and may help the organism by detecting and killing off pre-cancerous cells.
The crystallographic structure of the human apoptosis inducing factor in the form of a rainbow-coloured cartoon
But the word itself? I always thought it was a-poptosis, meaning the opposite or absence of “poptosis”. Like symmetry & a-symmetry. But I was wrong. It’s actually apo-ptosis, from the Greek meaning “falling from” (apo=from and ptosis=falling). The Greeks used it when flesh dropped from bones or scabs from sores and we could even use it at this time of year for leaves falling from trees.
Some people pronounce that “pt” in ptosis is with no P sound, just like the beginning of “pterodactyl”.
Although the ancient Greeks used it, the word was first coined in modern times by German scientist Carl Vogt in 1842, when describing the development of midwife toad tadpoles. Then another German, Walther Flemming, described it in more detail in 1885.
After that it went out of fashion until the 1960s, when electron microscopy allowed scientists to spot the difference between programmed cell death and unplanned, traumatic cell death.
Today apoptosis is a word much used in cancer research. To read more detail on all this, see Wikipedia.
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