Figure 2: Photosynthetic growth curve analysis of ΔcrtB RC/YFP–LH1.
(a) Light was provided using Megaman CFL bulbs at an intensity of 100 μmol photons s−1 m−2. Photosynthetic growth curves are shown for ΔcrtB RC/YFP–LH1 (red circles) and ΔcrtB (blue circles); a carotenoid-containing LH2-minus strain (green circles) is included as a positive control. (b) Superposition of the absorption of ΔcrtB, ΔcrtB RC/YFP–LH1 and purified YFP onto the emission output of the LEDs used for the photosynthetic growth rate experiment in c. ΔcrtB is shown in blue, ΔcrtB RC/YFP–LH1 in red and purified YFP in yellow; the spectra are normalized to their maximum values. The emission of the green LEDs (520 nm emission maximum, 35 nm FWHM) is indicated by the white region on the grey background. (c) Photosynthetic growth curves of ΔcrtB RC/YFP–LH1 (red circles) and ΔcrtB (blue circles) under green LEDs. A carotenoid-containing LH2-minus strain (green circles) is included as an additional control. Error bars indicate the s.d. from the mean; n=3. Each growth curve is representative of at least three independent experiments. The inset shows a quantification of YFP fluorescence, normalized for equal numbers of cells, showing that there was sufficient oxygen for maturation of the YFP chromophore.
