FIG. 1.

Validation of live or dead mycoplasma cell staining. A log-phase culture of M. mycoides subsp. mycoides LC was used as a live cell control (A, B, and C). Mycoplasma cells were heat injured at 60°C for 1 h (E, F, and G). (D) An artificial mixture of live and dead mycoplasma cells; (H) broth medium as a negative control. Cells were stained with SYBR and/or PI. Region R1 corresponds to live cells and region R2 corresponds to dead cells when the double stain was used. Region R3 corresponds to dead cells when only PI stain was used. When SYBR is used alone, it can stain both live and dead cells (R1).