Intracellular growth rates of L. monocytogenes in J774 cells between 5 and 8 h postinfectiona

StrainPresence of cytochalasin DbMean doubling time (min)c ± SDnPd
Wild type81.3 ± 17.880.538
+90.3 ± 34.15
plcBΔpro mutant118.4 ± 33.770.032
+74.3 ± 5.64
  • a Gentamicin (50 μg/ml) was present in the extracellular medium from 1 h postinfection until the end of the experiment.

  • b Cytochalasin D (0.5 μg/ml) was added to infected cells at 3 h postinfection.

  • c Doubling times were calculated as indicated in Materials and Methods.

  • d A two-sample t test was conducted to compare the intracellular growth rates with and without cytochalasin D for the wild-type strain (top value). The same test was conducted for the plcBΔpro mutant strain (bottom value).