Comparisons of the transferability of plasmids pCAR1, pB10, R388, and NAH7 among Pseudomonas putida at different cell densities.

The transferability of plasmids pCAR1, pB10, R388, and NAH7 was compared using the same donor-recipient system at different cell density combinations in liquid or on a solid surface. pCAR1 was efficiently transferred in liquid, whereas the other plasmids were preferentially transferred on a solid surface. Difference of liquid or solid affected the transfer frequency especially at lower cell densities.