Transduction of a spatial pattern in a single cell - the phototropism of Phycomyces

Leonid Fukshansky

The light driven growth acceleration in the sporangiophore of lower fungus Phycomyces is a well studied example of a transduction chain which operates within a single cell and changes its basic features upon a change in the geometry of stimulus ( symmetrical versus asymmetrical illumination). Such a transduction chain must be treated as a series of pattern formations. Due to lucid physical nature of the stimulus and simple geometry of the cell a quantitative treatment of the first patterns in this chain appeared feasible. This provides the resolution of some "paradoxes" and clarifies the mechanism of signal processing.