Video-enhanced microscopy of organelle movement in an intact epithelium.

Digitally enhanced video microscopy has provided improved optical resolution in the study of intracellular organelle/particle movement, particularly in extruded axoplasm and certain thin single cell systems. We report here, for the first time, particle movement in an intact, isolated epithelium, the killifish proximal convoluted tubule. Cytoplasmic particles exhibited predominantly unidirectional linear movement approaching several microns in length, sometimes with multiple turns. The velocities of 34 particles measured in 11 cells averaged 0.29 microns/sec (range, 0.007-3.1 microns/sec). Microtubules--the well-established basis for organelle movement in cells--were present but were sparsely represented in electron micrographs of these cells. Video-enhanced microscopic techniques can now be applied to the study of organelle/particle movement in an intact epithelium.