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. Author manuscript; available in PMC: 2012 Oct 1.
Published in final edited form as: FEMS Microbiol Lett. 2011 Aug 24;323(2):171–179. doi: 10.1111/j.1574-6968.2011.02373.x

Figure 2. Long-term growth and the expression of the GASP phenotype by L. monocytogenes.

Figure 2

(A) Long term culture growth curve of L. monocytogenes in BHI at 37°C. Bacterial growth and survival was determined by measuring CFU/mL at the indicated time points. Data shown represents the mean ± the standard error of three independent experiments. (B) L. monocytogenes expression of GASP. Bacteria from a 12-day old (12d), a passaged 12-day old (12d-P), or a 1-day old (1d) L. monocytogenes culture (test strains) were added to a 1-day old L. monocytogenes culture (reference strain). Mixed bacterial cultures were incubated in BHI at 37°C. Passaged 12-day old bacteria are bacteria from a culture that was aged 12 days and then diluted 1:100 in fresh BHI every 24 hours for a total of 12 passages (Fig 1B). The reference strains contained the stable integrated plasmid vector pPL2, which conferred chloramphenicol resistance. The test strains were chloramphenicol sensitive. The competitive index (CI) values were determined at the indicated time points as described in Materials and Methods, with Day 0 being the time point immediately after bacteria from a test strain culture were added to the reference strain culture. The data represent the means ± standard errors of three independent experiments.