Fig 1.

Kinetics of germination of a spore population. Spores of B. subtilis strain PS533 (wild type) were germinated with l-valine as described in Materials and Methods, and spore germination was monitored by Tb-DPA fluorescence (given in arbitrary units [a.u.]). The lag period prior to attaining the maximum germination rate is indicated. The maximum rate of germination was determined by the maximum linear slope of the Tb-DPA fluorescence increase, and the precise value for the lag time was determined by extrapolating the maximum rate of increase in the Tb-DPA fluorescence to the time axis, allowing the determination of the time between this point and the time of mixing of spores and the germinant.