Figure 2.

The maintenance of plasmids phsd⁺ and phsdR⁻ in NM679 compared with pBR322 (see Materials and Methods). The fractions of cells retaining plasmids are plotted on a log scale. Those for phsd⁺ and phsdR⁻ were based on the data of three experiments and those for pBR322 on two. No standard deviations are shown for the latter because there was negligible deviation.