FIG 9.

Germination of untreated and UV₂₂₂-killed B. subtilis wild-type spores. Spores of B. subtilis PS533 (wild type), either without or after UV₂₂₂ irradiation giving ∼99% killing, were germinated with l-valine, and spore germination was monitored by the fluorescence in relative fluorescence units (RFU) of released DPA with Tb³⁺. Symbols: ○, unirradiated spores; ●, UV₂₂₂-irradiated spores. Analysis of the spores by phase-constant microscopy at the end of the experiment showed that >85% of both types of spores had germinated completely (data not shown). a.u., arbitrary units.