VIEW ARTICLE    DOI: 10.1094/ASBCJ-48-0107

Curing Industrial Saccharomyces Yeasts of Parasitic 2 µm Plasmid. Wei Xiao and Gerald H. Rank, Department of Biology, University of Saskatchewan, Saskatoon, SK, Canada S7N 0W0. J. Am. Soc. Brew. Chem. 48:0107, 1990.

The 2µm circle plasmid is a parasitic DNA molecule found in laboratory Saccharomyces cerevisiae yeast. Our survey showed that most industrial Saccharomyces yeasts also contain 2µm DNA. A chimeric vector containing yeast SMR1 dominant resistance selectable marker cloned into native 2µm was used to cure endogenous 2µm DNA from yeast strains of baking, brewing, wine, and distilling origin. Competition tests with baker's yeast strain ATCC 7754 clearly demonstrated that 2µm DNA-free([cir° ]) derivatives conferred a growth advantage over their isogenic [cir⁺] cells. The 2µm-curing technology has a direct application to commercial food and beverage yeasts for enhanced growth efficiency. In addition, industrial [cir° ] are attractive candidates for recombinant DNA-based pharmaceutical production.

Keywords: Competition test, Industrial yeast, Selfish DNA, Southern analysis, Transformation, 2µm plasmid