Figure 1. Comparison of germination of C. difficile UK1 spores in presence/absence of terbium.

C. difficile UK1 spores were prepared from BHIS medium as described in the materials and methods. (A) CaDPA release from the purified spores was analyzed by suspending the spores in buffer supplemented with 250 μM TbCl₃ and (●) 30 mM glycine, (■) 10 mM TA or (▲) 10 mM TA and 30 mM glycine. The extent of germination was also analyzed by determining OD₆₀₀ over time. Germination by C. difficile spores was analyzed in the absence of TbCl₃ (B) or in the presence of 250 μM TbCl₃ (C). Data points represent the averages from three independent experiments and error bars represent the standard error of the mean. (D) Equal numbers of spores were incubated with or without 250 μM TbCl₃ in 30 mM glycine or 10 mM TA or 10 mM TA and 30 mM glycine for 2 hours and soluble proteins were extracted with NuPAGE buffer and separated by SDS-PAGE followed by immunoblotting with SleC- specific antisera.