FIGURE 4.

Effect of CSP concentration on transformation efficiency and culture density. S. mitis type strain pre-culture at OD₆₀₀ 0.5 was diluted 1:100 in C+Y_{Y B} and grown until OD₆₀₀ 0.04 at 37°C in 5% CO₂. Following, 500 μL aliquots were exposed to 150 ng mL^-1of the 7 kb amplicon donor (aRJ21) and CSP concentrations varying from 0 to 507 nM. Cultures were further incubated in closed tubes for 4 h at 37°C in air atmosphere. Optical density of the cultures was measured at the time of plating. The % of CFU containing Kan^R transformants was determined by plating on blood plates with or without 500 μg mL^-1 kanamycin. The results are averages from 3 replicates and representative of three independent experiments. Error bars represent standard error of the mean.