Figure 1. Possible artifact when measuring
lateral diffusion of rhodopsin. The two black noisy lines are
absorbance traces recorded in configuration a, with a measuring
beam jumping alternatively between the two sides of ROS. The arrow
indicates the moment at which a half-ROS bleaching flash was applied
(hatched area in a). Difference between absorbances at two ROS
sides generated by the flash further dissipates, supposedly due to
diffusional exchange by rhodopsins. Bold blue line shows the time
course of post-flash absorbance changes recorded in configuration b.
Here the measuring beam is placed at the ROS center and full-field
bleach applied, so no diffusion-related changes was expected.
Recordings are made in standard Ringer solution at pH 7.5.