Effect of chlamydial GlgA expression on glycogen synthesis and subsequent chlamydial infection.

<p>HeLa cells were transfected with pFlag plasmid alone or pFlag plasmid encoding chlamydial GlgA gene. Twenty-four hours after transfection, the cell samples were processed for immunofluorescence labelings with mouse anti-FLAG or anti-GlgA (A), harvested for glycogen detection (B) or further infected with <i>C. trachomatis</i> L2 (C). (A) The images were taken 24h after transfection under a 60X objective lens using a conventional fluorescence microscope. (B) HeLa cells with or without transfection with pFLAG or pFLAG-GlgA or infection with L2 were harvested 24h post-transfection or 48h post-infection for glycogen measurements. The results coming from 5 independent experiments were expressed as µg per ml of samples as shown along the Y-axis. Note that both exogenous GlgA overexpression and chlamydial infection significantly enhanced the levels of glycogen synthesis in HeLa cells (Student t-test). (C) Some of the transfected cells were further infected with chlamydial organisms and 40h after chlamydial infection, the cultures were processed for immunofluorescence labelings with mouse anti-FLAG to identify positive transfection cells and rabbit anti-chlamydial EBs to identify chlamydial inclusions. Number of total and <i>C. trachomatis</i>-infected cells was counted from 5 random views of each coverslip. The infection rate was calculated for anti-Flag positive (solid bar) and negative (open bar) cells respectively and expressed as mean plus/minus standard deviation along the Y-axis. Note that the infection rates displayed no statistically significant differences between cells with or without transfection from either pFLAG vector alone or pFLAG/GlgA recombinant plasmid-transfected cultures (p>0.05, Fisher Exact).