Bacteriophages benefit from generalized transduction
Fig 4
Generalized transduction (GT) allows phage to persist in the presence of antibiotics.
RN4220 was infected with GT pac phage, ϕ11 (A) or non-GT, cos-phage ϕ12 (B) propagated on strain JH930 harboring pRMC2 encoding resistance to chloramphenicol. After 8 generations of growth the total number of bacteria and the number of chloramphenicol-resistant transductants were determined. Then, each culture was diluted 1000 fold in media containing a lethal concentration (30μg/ml) chloramphenicol and grown for 8 generations. The dilution step was repeated and the cultures were allowed to grow for additional 8 generations after which CFU of all cultures was determined on plates with or without chloramphenicol. Hundred transductants (or just survivors in case of ϕ12) were tested for lysogeny. Percentage over graphs indicate percentage of lysogens of total number of colonies tested.