The baffling intelligence of a single cell (2024)

A deep, richly illustrated exploration of E. coli chemotaxis explains how a single bacterial cell senses chemical gradients and decides whether to swim ('run') or tumble. The mechanism hinges on a signaling molecule, CheY, that gets phosphorylated by receptor complexes and binds flagellar motor proteins to trigger direction changes. The piece details receptor methylation as a form of chemical memory enabling adaptation across five orders of magnitude of attractant concentration, the physics of the flagellar motor (self-assembling, nearly 100% energy efficient, spinning at 1,500 rotations per second), individuality among genetically identical bacteria due to small protein copy-number variation, and the historical experiments (genetic knockouts, in vitro biochemistry, structural imaging, computer modeling) that revealed this picture. It closes by reflecting on chemotaxis as a model system for understanding broader cellular signaling and potential medical applications like new antibiotics or cancer-targeting 'intelligent sniffers'.

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