Autofluorescence at different growth conditins.

<p>Microscopy fields of SF214 cells grown at different conditions and observed by phase contrast and autofluorescence and compared to assess the proportion of fluorescent vs not fluorescent cells. Left panel: exponential vs. stationary growth phase (in LB medium at 37°C); middle panel: 25°C vs. 37°C as growth temperature (in LB medium for 24 hours); right panel: minimal (S7) vs. rich (LB) growth medium (stationary cells grown at 25°C). For each panel a graph reports the percentage of fluorescent (gray bars) vs. not fluorescent (dark gray bars) cells. For each condition a total of 1.000 cells from five different microscopy fields were counted. Spores and cells containing a prespore were not counted.