THE EFFECT OF SURFACE-ACTIVE AGENTS ON COLOR VARIATION IN AGING POPULATIONS OF SERRATIA MARCESCENS

Abstract

Expts. with the relatively stable Hy strain of J. marcescens have demonstrated that the increase in the proportion of white color variants that is induced in aging cultures of mixed red and white cells by low concentrations of surface-active agents depends on selective rather than mutagenic action. Toxic concn. of surface-active agents were more lethal to white than to red cells. Low concns. have no obvious effect in rapidly growing cultures but permit the white variants to continue growth after the red type has begun to decline. The selective mechanism in aging cultures appeared to be an indirect consequence of the autolytic action of the surface-active agents, which released into the medium substances that selectively favored the growth of the white type. There was some evidence that the effective materials were carbohydrates.