Periphery of inclusions rather possess non-metabolized TFSM compared to their center. The image depicted in ( a ) was zoomed, and the metabolic state of TFSM was calculated by determining the ratio of 3-times Forster resonance energy transfer (FRET) vs. donor (BODIPY-FL) signal. White arrows indicate intermediate chlamydial developmental forms. n = 3. Scale bars: 8 µm (with 4-fold expansion factor ~ 2 µm).
