FIG 4.

Germination of HP-pulsed B. subtilis spores subsequently incubated at ambient pressure. (A) Wild-type B. subtilis spores were continuously exposed either to 150 MPa of HP (■) or to 150 MPa for 5 min (•), 2 min (▲), 1 min (▼), or 10 s (◀), followed by immediate exposure to atmospheric pressure (0.1 MPa) and subsequent incubation at 37°C, all as described in Materials and Methods. Arrows indicate time points at which the HP pulse was ended. (B) The percentages of spores that released their CaDPA after a 150-MPa HP pulse for different times and subsequent incubation in a PT-1 pressure unit (●) or in a DAC (□) were determined by LTRS analysis of 50 individual spores to determine the percentage of spores that had lost their CaDPA. The percentage of spores that were HP pulsed and then incubated (□) was determined from the data in panel A.