Abstract
Two novel covalently closed circular DNA species of 5.4 and 6.0 kilobases were detected in strains of Zygosaccharomyces bailii with a rapid small scale isolation procedure. The 5.4 kb species was found in four strains and both species were found in three strains. A novel, covalently-closed circular DNA species of 6.9 kb was detected in four of 12 strains of Pichia membranaefaciens . Plasmid DNA (2 micron) (that is CCC DNA of approximately 6 kb in Saccharomyces cerevisiae) was detected in 38 of 40 strains of Sacch . cerevisiae confirming reports of the widespread distribution of this plasmid.