Figure 7. Kinetics of GFP production by the L. biflexa reporter strains (P41G, PAG and P2G), after exposure to a combination of physiological salt levels, temperature upshift to 37°C and supplementation with spermine.

Cultures of the reporter strains P41G (A), PAG (B) or P2G (C) were induced by a combination of physiological osmolarity (PO), temperature upshift (TS) and 200 µM spermine (intracellular level) (SP). The induced wild-type control (P-24) and the uninduced reporter strains (NI-24) were included as controls. Transcriptional activity was measured for 24 h and presented as the mean ± standard error (bars). Fluorescence from triplicate samples of each culture were standardized according to an OD₄₂₀ 0.5 and are expressed as arbitrary fluorescent units. Data from a representative significant study are shown.