FIG. 3.
(a) Lysis in broth experiments comparing the lysis profiles of MG1363 harboring pNZ44 in both uninfected cells (▪) and cells infected (□) with sk1 and its derivatives bearing siemg2 (uninfected, X with short dashes; infected, X with long dashes), sieT712 (uninfected, ▴; infected ▵), sie309 (uninfected, •; infected, ○, and sie312 (uninfected, ⧫; infected ⋄). OD600 readings were taken at 15-min intervals. Each of the active Sie proteins provides resistance against sk1 infection. MG1363 harboring pNZ44 was used as a positive control. Each assay was performed in triplicate. (b) Lysis in broth experiments of L. lactis MG1363(pNZ44) cells both uninfected (⧫) and infected (⋄) with sk1 and its derivatives bearing the putative Sie genes orf2141mg3 (uninfected, ⧫; infected, ⋄) and orf2286 (uninfected, ▪; infected, □). OD600 readings were taken at 15-min intervals. These systems appear to provide little or no protection against infection by sk1.