Change of membrane potential is not a component of the photophobic transduction chain in Halobacterium halobium.
Long (20 to 50 microns) and bipolarly flagellated cells of Halobacterium halobium were stimulated locally by a focused beam of light, and the photophobic response was analyzed. The results demonstrate that two flagellar bundles did not react in a coordinated fashion. The light-induced stop response of a flagellar bundle only occurred if the stimulus was applied within 5 microns of the polar region. This excluded membrane potential changes from being causally involved in photophobic signalling and indicated that there is a diffusible messenger in the signal transduction chain which is subjected to decay. In addition, the photoreceptor may be localized at the polar end of the cell.
D002465:Cell Movement / Q000528:radiation effects; D005407:Flagella / Q000502:physiology* / Q000528:radiation effects; D006217:Halobacterium / Q000502:physiology* / Q000528:radiation effects / Q000648:ultrastructure; D008027:Light; D008564:Membrane Potentials / Q000528:radiation effects