Ancient bacterial

Swiss researchers have reported the restoration of light sensitivity in animal models of retinitis pigmentosa (RP) using an ancient protein isolated from archaebacteria. The protein, “halorhodopsin”, is a light activated chloride pump that was used by the researchers to bypass the normal opsin found in cone photoreceptors. In patients suffering RP, rod photoreceptor cell death generally precedes cone cell death however, while remaining cones survive, there may be an opportunity to maintain a level of visual function by transferring the light activated halorhodopsin into cone cells. If the cones maintain the ability to process signals to second order neurons then stimulation of the normal visual circuitry may sustain functional vision even in a damaged retina [Science, Vol. 329, pp413-417].