Down regulation of Beclin-1 reduced the co-localization of E. coli with autophagosomes. (A) HMrSV5 cells transfected with negative control siRNA or Beclin-1 siRNA were infected with fluorescent E. coli (green) for 1 hour of uptake, followed by a 12 hours chase in LPS (1.0 μg/ml). Afterwards, autophagic vacuoles were labeled with MDC (blue). Scale bars: 20 μm. (B) Quantitation of the co-localization of E. coli with the MDC-labeled autophagosomes in Figure 8A (mean values ± SD, n ≥ 3). **p < 0.01 (vs. control); # p < 0.05 (vs. LPS).