Abstract
Little is known about factors affecting plasmid maintenance in natural populations of bacteria. To study the effects of limitation of carbon and energy sources on plasmid maintenance, the fate of R100-1 and RSF2124 plasmids in model populations of Escherichia coli was investigated under nutrient-poor and anaerobic conditions. Nutrient-poor and anaerobic conditions adversely affected the maintenance of the plasmids. In batch culture experiments the plasmid loss was observed during the logarithmic phase of growth. Continuous culture experiments showed that nutrient-poor and anaerobic conditions strongly decreased the maintenance of plasmid-carrying populations under the competition with plasmid-free segregants.
