title: Bacteriorhodopsin induces a light-scattering change in Halobacterium halobium.
abstract: When suspensions of Halobacterium halobium are exposed to bright light, the light-scattering properties of the bacteria change. This light-scattering response can produce a transmission decrease of about 1% throughout the red and near-infrared region. The action spectrum for the light-scattering response appropriately matches the absorption spectrum of bacteriorhodopsin. The response is eliminated by cyanide p-trifluoro-methoxyphenylhydrazone, a proton ionophore, and by triphenylmethylphosphonium, a membrane permanent cation. A mild hypertonic shock induces a similar light-scattering change, suggesting that bright light causes the bacteria to shrink about 1% in volume, thereby producing the light-scattering response.
mesh_terms: D000222:Adaptation, Physiological; D000332:Aerobiosis; D001436:Bacteriorhodopsins; D002338:Carotenoids; D002452:Cell Count; D003624:Darkness; D006217:Halobacterium / Q000166:cytology / Q000502:physiology*; D006863:Hydrogen-Ion Concentration; D008027:Light; D012462:Saline Solution, Hypertonic / Q000494:pharmacology; D012542:Scattering, Radiation
chemical_list: D012462:Saline Solution, Hypertonic; D002338:Carotenoids; D001436:Bacteriorhodopsins