FIG 4.
Germination and PC image intensities of individual B. subtilis spores germinating with l-valine and after l-valine was replaced by d-alanine. PS533 spores (wild type) were germinated with 10 mM l-valine (a to c) at various temperatures or with buffer alone at 45°C (d), and spore germination was monitored by PC image intensity changes as described in Materials and Methods. In panels a to c, after 10 min the germinant was removed and replaced with 10 mM d-alanine, and incubations were continued at initial incubation temperatures. PC image intensities (a.u.) were normalized to 1 based on the respective values at the first time of measurement and with PC image intensities at the end of the experiment set at 0. The arrows indicate the times of T1, Tlag, Trelease, and Tlysis for a single spore. In panel a, the germination curves at the different temperatures are from data with >217 spores each, and a germinated spore was defined as one that had reached Trelease.