Affinity of cellular constituents of two bacteria for fluorescent brighteners.

Two fluorescent brighteners were used to stain an isolate of Bacillus cereus var. mycoides and soil pseudomonad. The stained organisms were fractionated by two procedures to determine which cellular constituents were reacting with the brighteners. Both fractionation procedures provided evidence that the brighteners were adsorbed to proteins within the cells. Microscopy examination of ghost cells of the bacillus showed that cell walls were not being stained. Spheroplasts of the bacillus and the pseudomonad were stained by the brighteners.