Stk influences primary attachment and PIA production in vitro.

A. Influence of Stk and Stk domains on primary attachment. The stk mutant strain was complemented with plasmids expressing different domains of Stk: pQG71, full length; pQG72, kinase domain; pQG73, transmembrane domain; pQG74, PASTA repeated domain; pQG75, C-terminal domain; pQG76, kinase domain without ATP-binding site; pQG80, kinase domain with D133E mutation; pQG81, kinase domain with D126E mutation, and primary attachment was determined. Data were derived from three independent experiments, with 4 replicates in each experiment. *, P<0.05 (versus WT). B. Influence of Stk and Stk domains on polysaccharide intercellular adhesin (PIA) production. PIA was determined in the same strains as in (A) using immunodot blots with anti-PIA serum and photodigital evaluation. Values represent the means ± standard errors of the means from three independent experiments, *, P<0.05 (versus WT).