Fig. 1.
Salmonella engulfment at various densities of Tetrahymena. For each density of protozoa, Salmonella and Tetrahymena were co-cultured using a multiplicity of infection equal to 10,000 (i.e., bacteria:protozoa ratios of 109:105, 108:104, 107:103, 106:102, and 105:101). Bacterial engulfment (average number of bacteria engulfed per cell) was determined after lysing protozoa. Each data point represents the mean ± sem for three independent experiments each performed in triplicate. *p<0.05 versus the rest of the data.