A Factor Involved in Chloramphenicol Resistance in Streptomyces coelicolor A3(2): Its Transfer in the Absence of the Fertility Factor

Abstract

An element controlling chloramphenicol resistance (chl) was detected in S. coelicolor A3(2). Strains sensitive to 1 .mu.g chloramphenicol ml-1 were obtained among dark scarlet variants. Transfer of the resistance factor was attempted in matings between chloramphenicol-resistant (Chl+) and chloramphenicol-sensitive (Chl-) strains, both of which lacked the SCP1 fertility factor. Transfer of chl was obtained at a much higher rate than that expected for chromosomal markers in SCP1- .times. SCP1- matings. In these particular crosses the latter was also several times higher than usual. All recombinants for chromosomal markers were Chl+. Attempts to locate the chl element failed to distinguish between a chromosomal and an extrachromosomal site. The observed increase in the recombination frequency for chromosomal markers suggests that the chl element may promote recombination.