FIG. 2.

Expression of inv and invasin protein levels in strain JB41v when flhDC is present on a multicopy plasmid. Units of alkaline phophatase activity (AP activity) were measured and cultures were grown as described in Fig. 1. (A) Alkaline phosphatase activity was measured for strain JB41v alone (□) and when containing the parental cloning vector (pTM100) (×), a plasmid-encoded clone of flhDC (pGY10) (●), or a plasmid-encoded flhDC::TnMax2 derivative (pGY10*) (▵). (B) Levels of invasin protein were determined by immunoblot analysis using an anti-invasin polyclonal antibody (16). Cultures were grown as described in panel A, and samples were normalized by examining equivalent units of optical density. The arrow indicates the position of full-length invasin.