Confocal fluorescence microscopy of mating pairs of Tetrahymena thermophila labeled with antiserum to tubulin (blue), TCBP-25 (red), and sytox nuclear stain (green).

Confocal fluorescence microscopy of mating pairs of Tetrahymena thermophila labeled with antiserum to tubulin (blue), TCBP-25 (red), and sytox nuclear stain (green).

(Source: stolaf.edu)