Fig. 1. Role of phage and SaPIs in plasmid transfer.

S. aureus strains lysogenic for phage 80α with or without SaPI1 or SaPIbov2 and carrying plasmids a pC221 (4.6 kb; blue circles), b pI258 (29 kb; green circles) or c pGO1 (54 kb; red circles) were induced with mitomycin C to produce lysates. Log₁₀ transductants (TrU) per ml of lysate were determined for each plasmid in an RN4220 recipient. All data is the result of three independent experiments (n = 3). Data for each donor strain are represented as boxplots where the middle line is the median, the lower and upper hinges correspond to the 25^th and 75^th percentiles, and the whiskers extend from the minimum to maximum values, with all individual data points shown as coloured circles. A one-way ANOVA with Tukey’s multiple comparisons test compared mean differences between each strain and the 80α control. Asterisks denote significant adjusted p values: a ***p = 0.0002, *p = 0.0355; b **p = 0.0038, ***p = 0.0001. All other values were not significant.