A Plasmid Involved in Chloramphenicol Production in Streptomyces venezuelae: Evidence from Genetic Mapping

Abstract

To test the hypothesis that chloramphenicol production in S. venezuelae depends on the presence of a plasmid, mapping analysis was carried out by using 8 markers in addition to chloramphenicol production and melanoid pigment formation. The sequence of the 8 markers was determined on a circular linkage map as follows: -his-ade-str-leu-lys-met-ilv-pro-(his-). This sequence resulted in the frequency of quadruple crossover (q.c.o.) recombinants having the lowest value, 3.2-4.9%. The character of chloramphenicol non-production, which was obtained by incubating mycelia with acriflavine, was not located on this linkage map; more than 15% q.c.o. recombinants would have been required to explain the results. Chloramphenicol production is apparently controlled by a plasmid which appeared to be non-transferable in conjugation.