Fig. 1. Construction of the stp1 deletion mutant of Streptococcus suis type 2 and its identification by polymerase chain reaction (PCR). (A) Schematic representation of the allelic exchange of chromosomal stp1 with vector-carried cat between pSET4s-Δstp1 and the chromosome of ZJ081101 by homologous recombination. (B) PCR confirmation of the mutant strain Δstp1. Lane 1, primers gadph and cps2J for Δstp1; Lane 2, gadph and cps2J for ZJ081101; Lanes 3, 5, and 7, primers In1/In2, Cat1/Cat2 and Cat1/Out2 for Δstp1; Lanes 4, 6, and 8, primers In1/In2, Cat1/Cat2 and Cat2/Out1 for ZJ081101; M, Marker DL2000. (C) Stp1 protein is absent in the stp1 mutant as determined by western blotting with anti-Stp1 polyclonal antibody (CPP, cytoplasmic proteins; CWP, cell-wall proteins).
