Fig. 3.

Growth and invasion characteristics of SL-pEGFP. Wild type SL7207 and SL-pEGFP were compared for growth rate (a) and capacity to invade MDA-MB-231 tumour cells (b). CFU counts of SL7207 and SL-pEGFP recovered from MDA-MB-231 cells at 2 h post infection. (c) Quantification of the proportion of bacteria in culture expressing SPI-1 at mid-log phase using the SPI-1 reporter strain, JH3010. JH3016 served as a positive control as it is a constitutively expressing GFP strain. SL-pEGFP served as a negative control for GFP expression as EGFP was under the control of the CMV promoter. Results displayed are the average of three independent biological replicates. Error bars SEM. These experiments were conducted in liquid culture. Statistical analyses performed using a Students t test (b) or One Way Anova (c) where p < 0.05*, p < 0.01**. p < 0.001***, p < 0.0001****