Mechanism of gram stain reversal.

This paper deals with an investigation of the effect of these reactions on bacteria. Not only the common staining behavior but also certain other similarities (Fischer et al., 1949; Fischer, 1951) between intact wool and gram negative bacteria, medium degraded wool and gram variable bacteria, as well as between highly degraded wool and gram positive bacteria suggested that reversal of gram staining in bacteria and in wools might be brought about by the same chemical treatments. For example, the bactericidal activity of anionic and cationic compounds could be predicted (Fischer and Seidenberg, 1951) from their affinity (Fischer et al., 1951) toward the three types of wool (Fischer and Larose, 1952). These affinity values are related to each other as the bactericidal activities of the compound toward gram negative, gram variable, and gram positive vegetative bacteria, respectively. The relationship of bactericidal action to the gram staining behavior can be expressed quantitatively (unpublished data) and indicates a possible common underlying cause of the two phenomena. The similarity in behavior between gram negative, gram variable, and gram positive bacteria on the one hand and intact wool, medium degraded, and highly degraded wool on the other apparently is caused by some structural feature common to the wool and to the bacterial cytoplasmor cytoplasmic membrane. Wool is known to have an a-keratin structure, and Astbury and Weibull (1949) showed that the same structure is present in bacterial flagella which arise in or near the cytoplasmic membrane (Bisset, 1950). The partly reversible chemical changes in the wool protein during alkaline or