Open AccessThe photodynamic action of methylene blue on bacteriophage
Author(s) -
J. R. Perdrau,
Charles W. Todd
Publication year - 1933
Publication title -
proceedings of the royal society of london. series b, containing papers of a biological character
Language(s) - English
Resource type - Journals
eISSN - 2053-9185
pISSN - 0950-1193
DOI - 10.1098/rspb.1933.0010
Subject(s) - methylene blue , bacteriophage , chemistry , staphylococcus aureus , incubation , microbiology and biotechnology , methylene , oxygen , photochemistry , escherichia coli , biology , bacteria , biochemistry , organic chemistry , genetics , photocatalysis , gene , catalysis
In the course of some work on the trypsin susceptibility of two races of staphylococcus bacteriophage, Schultz and Krueger (1928) made the observation that these two phages were remarkably sensitive to the action of methylene blue─being completely inactivated within 6 to 12 hours by concentrations of the dye as low as 0.002 per cent. So far as their tests went, the susceptibility to methylene blue appeared to be peculiar to the two races of staphylococcus bacteriophage, as eight phages for other organisms were entirely unaffected by the dye. Moreover, of a considerable number of dyes used, methylene blue was the only one showing this action. Clifton and Lawler (1930) and Burnet and McKie (1930) repeated these experiments with methylene blue and other dyes on several strains of bacteriophage, but they were then unaware of the role played by light in these reactions. A new aspect of the mechanism of the reaction was opened up by Clifton (1931), who found that no inactivation took place when the dye and the phage were mixed, incubated and tested in the dark ; but that an exposure of 5 minutes, or even less, to indirect sunlight before incubation resulted in complete inactivation of the bacteriophage. He also showed that the presence of oxygen was necessary for the process, as inactivation did not occurin vacuo or in an atmosphere of nitrogen, and was inhibited by reducing agents such as cysteine hydrochloride. He therefore concluded that the inactivation of the staphylococcus phage by methylene blue is due to an oxidation of the phage by photosensitized methylene blue in the presence of oxygen.