The Distribution of Color Variants in Ageing Broth Cultures of Serratia Marcescens #274

Abstract

[longdash]When cultures were allowed to age in a synthetic broth medium at 30[degree]C, the populations changed in a reproducible manner. During the early stages, cells which produced typical dark red colonies tended to predominate; after the death phase had set in, pink and sometimes white colony-forming cells increased until at the end of approx. 2 weeks < 50% of the colonies on pour plates were dark red; this was followed by a 3d stage in which the relative number of dark red cells again increased. This pattern of variation, which has been observed in over 100 cultures, was independent of the per cents of dark red, pink or white cells in the original inoculum.