Table 1.

Evolution of S. enterica serovar Typhimurium SL1344-induced localized apical F-actin accumulations in control and treated Caco-2 cellsa

Caco-2/TC-7 cell treatment groupMean no. of accumulations (± SEM)b observed at postinfection h:
245
Control infected cells36 ± 320 ± 315 ± 2
Infected cells treated with MRS-HCl20 ± 4* 12 ± 2*
Infected cells treated with MRS-LA19 ± 5* 14 ± 2*
Infected cells treated with LB-SCS12 ± 1.5** 4 ± 0.5**
  • a Caco-2/TC-7 cells were infected with 108 CFU of serovar Typhimurium/ml for 2 h. Infected cells were treated for 1 h with DMEM (control), LB-SCS, or MRS-LA. Localized F-actin rearrangements, revealed by direct immunofluorescence labeling with fluorescein-phalloidin, were counted at 2, 4, and 5 h postinfection. For treated cells, the observations at 4 and 5 h postinfection correspond to those at 1 and 2 h posttreatment, respectively. Results presented are the mean ± SEM of the localized apical F-actin accumulations per microscopic area (20 random microscopic areas were examined per monolayer) for nine monolayers resulting from three separate experiments (three successive cell passages).

  • b ∗, values for control and treated cells were not significantly different (Student's t test); ∗∗, values for control and treated cells were highly significantly different (P < 0.01; Student's t test).