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Updated: Aug 12, 2026

Desensitization and Recovery of Crayfish Photoreceptors Upon Delivery of a Light Stimulus
Published on: November 9, 2019
Photoreactivation
1Auerback Melanoma Laboratory, University of California, UCSF Cancer Center, Room N431, Box 0808, San Francisco, CA 94143-0808, USA. jcleaver@cc.ucsf.edu
Abstract:
Kelner and Dulbecco first reported in the 1940s and 1950s the reversal of ultraviolet damage in bacteria and phage by illumination with visible light. The first publications, reprinted here, represented the discovery of a widespread repair mechanism that was named "photoreactivation" (PHR), that directly reversed photoproducts to their individual pyrimidine components. Between them, these pioneers demonstrated that photoreactivation had a cellular basis, could be defined by wavelength optima indicating specific molecular photoreceptors, and had a widespread phyletic distribution except for its absence from placental mammals.
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