Fig. 6. Inactivation of ampA gene function results in a decrease in the number of cells expressing the ampA reporter in the region of the upper cup during late development. ampA reporter gene expression patterns for wild-type (A,C) and ampA– (B,D) structures formed by axenically grown cells are shown. (A,B) Early culminants (18 hours development); 29 hours staining. (C,D) Culminants (24 hours development); 20 hours staining. Arrows indicate the regions of the upper cup where reporter expression is reduced in ampA– aggregates relative to wild type. (E-H) Wild-type and ampA– cells were grown in the presence of bacteria. Suspensions of wild-type cells, ampA– cells or wild-type/ampA– cell mixtures were plated for 18 hours of development. Samples were fixed and stained 22 to 24 hours for ß-galactosidase activity. (E) 100% wild-type cells, reporter in all cells; (F) 100% ampA– cells, reporter in all cells; (G) 50% wild-type cells/50% ampA– cells, reporter in all cells; (H) 50% wild-type cells/50% ampA– cells, reporter in ampA– cells only. Arrows indicate regions of the structures where upper cup cells should be found.
