FIG 4.

Germination of PS533 spores (wild type) with continuous l-valine exposure or two short l-valine pulses. (A) Germination of spores with 10 mM l-valine for 90 min (◼) or for 2.5 (•), 5.0 (▲), or 7.5 (▼) min followed by germinant removal by method A, further incubation at 37°C for 45 min, and a second 2.5-min exposure to 10 mM l-valine (vertical arrows), followed again by germinant removal by method A and further incubation until 90 min, although there were no significant changes after 70 min. Values shown are from data for ∼400 individual spores determined as described in Materials and Methods. (B) Time-lapse DIC image intensities of ∼20 individual spores germinating with 10 mM l-valine for 60 min. (C and D) Time-lapse DIC image intensities of ∼20 individual spores germinating with 10 mM l-valine for 2.5 (C) or 7.5 min (D), after which the germinant was removed and the spores were rinsed 6 times with buffer, incubated in buffer until 45 min, and reexposed to 10 mM l-valine for 2.5 min, followed by rinsing again and incubation in buffer for 45 min at 37°C. DIC image intensities of individual spores were followed as described in Materials and Methods, and there were only a few notable changes after 70 min.