[Enhanced formation of plaque in RNA phages/bacteria systems under the effect of surface-active preparations].

The effect of 21 surfactants on the plaque formation was tested in three RNA-phages/Escherichia coli systems and in one RNA-phage/Pseudomonas aeruginosa system. Especially anionic detergents proved to be able to influence the plaque formation substantially. In high concentrations of Metaupon, Fekunil 602, Fekunil S-BA, Emulgator W 270, and Emulgator O-BA the plaque formation by the phages M 12 and f2 was inhibited and in low concentrations it was promoted. In the system Q beta/E. coli AB 301 the effect of the detergents mentioned was restricted to the prevention of the appearance of plaques. The detergent E 30 brought about only plaque inhibitions, too, in all used RNA-phages/E. coli systems. The treatment with effective detergents in the system PP7/P. aeruginosa, however, increased only the number of plaques. This phenomenon was evident in the formation of radiate plaque patterns in the lawn of bacteria. In the case of RNA-phages of E. coli the formation of such trains of lysis depends on the choice of the nutritive medium. The addition of the detergent Fekunil 602 at different times after the contact between phages and host bacteria affects the length of the beams of lysis. The ionogenity of surfactants seems to be of importance for the formation of radiate plaque patterns, since the tested cationic compound and the nonionic surfactants, contrary to anionic surfactants, did not cause any beams of lysis.