A Description of Some Color Variants Produced by Serratia marcescens , Strain 274

Abstract

When a stock culture was plated on a well buffered, synthetic, ammonium citrate-glycerol medium, colonies of 4 colors[long dash]dark red, bright pink, pale pink and white[long dash]were produced. 3-day-old colonies of each of these color types were replated by the pour method. Each colony gave rise to numerous daughter colonies of the parent type, and, in addition, variants of one or more of the other color types. The % of variants was characteristic for each type of parent colony. Each of the 4 colony types probably arose from a different type of cell, these cell types could probably be characterized by their pigmentation and stability. The compositions of 3-day-old colonies of each type, as revealed by plating on the synthetic medium, were not affected by selective replatings carried on over a period of 6 mos. Preliminary analyses of the pigments in dark red colonies revealed the presence of 2 major components; it is not yet known whether either of these is lacking from the pink cells.