Figure 4
From: Real-time detection of viable microorganisms by intracellular phototautomerism
RTV assay kinetics obtained with different microorganisms. Salicylic acid (2 mM) was dissolved in 100 mM phosphate buffer and added to either live cells. Excitation was performed at 295 nm, emission at 405 nm. Fluorescence signals are shown for representatives of (A) bacterial cells at pH 2, (B) bacterial spores at pH 1 and (C) fungal spores at pH 1, and (D) a composite sample of B. subtilis spores and vegetative cells at pH 1.