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“Cell suicide” is inherently self-destructive, and yet it’s an essential and productive process in complex organisms. How did cells evolve a process to end their own lives? As Veronique Greenwood reports, recent research suggests it first arose, first arose billions of years ago… but why?…

It can be hard to tell, at first, when a cell is on the verge of self-destruction.

It appears to be going about its usual business, transcribing genes and making proteins. The powerhouse organelles called mitochondria are dutifully churning out energy. But then a mitochondrion receives a signal, and its typically placid proteins join forces to form a death machine.

They slice through the cell with breathtaking thoroughness. In a matter of hours, all that the cell had built lies in ruins. A few bubbles of membrane are all that remains.

“It’s really amazing how fast, how organized it is,” said Aurora Nedelcu, an evolutionary biologist at the University of New Brunswick who has studied the process in algae.

Apoptosis, as this process is known, seems as unlikely as it is violent. And yet some cells undergo this devastating but predictable series of steps to kill themselves on purpose. When biologists first observed it, they were shocked to find self-induced death among living, striving organisms. And although it turned out that apoptosis is a vital creative force for many multicellular creatures, to a given cell it is utterly ruinous. How could a behavior that results in a cell’s sudden death evolve, let alone persist?…

The story in full: “Cellular Self-Destruction May Be Ancient. But Why?“, from @vero_greenwood in @QuantaMagazine.

* Shakespeare, Hamlet (Act 5, Scene 2)

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As we appreciate apoptosis, we might send healthy birthday greetings to Lillian Wald; she was born on this date in 1867.  A nurse, humanitarian, political reformer, and author, she was instrumental in establishing a nationwide system of nurses in public schools.  Known as “the Angel of Henry Street” (for her founding and running of the Henry Street Settlement in New York City), she directed the Henry Street Visiting Nurse Service, while at the same time tirelessly opposing political and social corruption.  She helped initiate the revision of child labor laws, improved housing conditions in tenement districts, drove the enactment of pure food laws, championed and improved education for the mentally handicapped, and led the passage of enlightened immigration regulations.

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