(a,b) Production of phagosomal PtdIns(3) P in E. coli-containing phagosomes of primary peritoneal macrophages transfected with reporter cDNA encoding an eGFP-tagged PX domain of p40phox (p40 PX-eGFP) and treated with DsRed-expressing E. coli (E. coli-DsRed; a) or beads coated with E. coli outer membrane extract (b). Numbers in bottom right corners indicate time (in min). Original magnification, ×60. Right, quantification of fluorescence in microscopy at left. 