Fig. 6

Host interaction phenotypes upon deletion of bcsZ in S. Typhimurium UMR1. a Invasion of epithelial cells by UMR1 (WT) and bcsZ mutant derivatives. b Uptake of UMR1 (WT) and bcsZ mutant derivatives in IFN-γ activated murine RAW264.7 macrophages at 2 h post infection (MOI of 10). For a and b, error bar indicates SD. c Intracellular proliferation (as fold change of uptake) of bcsZ mutant derivatives at 16 h post infection. Error bar indicates SD for two independent experiments, each in triplicates. For a–c, ***p < 0.0005, **p<0.001, *p < 0.05; ns not significant compared to WT-VC unless specified using paired t-test. d Competitive index (CI) of virulence of UMR1 (WT) against bcsZ mutant derivatives in organs of 6–8 week old female BALB/c mice (5 per group) on day 1 and 3 post oral infection. Each circle represents an individual mouse and error bar indicates SEM. Infection dose (ID) used for inoculation with a strain ratio of 1:1 for UMR1 (WT) and bcsZ mutant derivatives. Significance calculated for mean CI in organs at different time points compared to the inoculum and for the difference in CI for bcsZ mutant derivatives in the same organ at one time point. Difference between inocula is not statistically significant. e CI of fitness of UMR1 (WT) against bcsZ mutant derivatives for uptake (2 h) and proliferation (16 h) in IFN-gamma activated murine RAW264.7 macrophages (MOI of 10). All results are the means and error bar indicates SD for independent experiments, each in triplicates. Significance calculated for the average CI in uptake and proliferation compared to the inoculum and for the difference in CI for bcsZ mutant derivatives for uptake and proliferation. Difference between inocula is not statistically significant. *p < 0.05, ns not significant. f CI of fitness of UMR1 (WT) against bcsZ mutant derivatives in LB broth at 6 h and 16 h post inoculation. All results are the means and error bar indicates SD of two independent experiments, each in triplicates. Significance calculated for the average CI at different time points after inoculation compared to the inoculum and for the difference in CI for bcsZ mutant derivatives at different time points. Difference between inocula is not statistically significant. For d–f, ***p < 0.0005, **p<0.001, *p < 0.05; ns not significant using Kruskal–Wallis assessment with subsequent Dunn’s test to compare to inoculum and one-tailed unpaired t-test to compare two samples at the same time point