Increased resistance to chloramphenicol in cells expressing the most efficient ribozyme isolated from the evolution.

<p>The doubling time of <i>E.coli</i> cells in medium containing chloramphenicol is plotted as function of chloramphenicol concentration. The evolved ribozyme (triangles) facilitated shorter doubling times than the parent ribozyme (circles). Note that the horizontal scale is broken to denote the doubling time of both constructs in the absence of chloramphenicol. Error bars denote standard deviations from the geometric means of at least three independent experiments. If error bars are not visible they are smaller than the symbols.