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Fig. 2 | Microbial Cell Factories

Fig. 2

From: Light-induced gene expression with photocaged IPTG for induction profiling in a high-throughput screening system

Fig. 2

Fluorescence spectrum of an E. coli Tuner(DE3)/pRhotHi-2-LacI-EcFbFP culture before and after optical induction. 2D fluorescence scan with excitation wavelengths from 300–600 nm and emission wavelengths from 320–600 nm before (a) and after optical induction (b: 10 min, c: 5 h). Ten minutes after UV-A irradiation for optical induction a fluorescence signal with an excitation maximum at 335 nm and an emission maximum at 405 nm is detected (b). Five hours later this signal is reduced by about 60 % and a strong fluorescence signal of the target protein FbFP with an excitation maximum at 450 nm and an emission maximum at 495 nm is detected (c). Biomass autofluorescence was detected but is not visible in this plot because other fluorescence signals are much stronger. Cultivation conditions: 800 µL Wilms-MOPS mineral medium (20 g/L glucose, 0.2 M MOPS) per well in a 48-FlowerPlate, 30 °C, shaking frequency: 1000 rpm, shaking diameter: 3 mm, 400 µM cIPTG added at the start of cultivation, optical induction with LED array after 10 h of cell cultivation for 6 s (λmax = 368 nm, I = 52 mW/cm2)

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