Fig. 1

CPD induction and repair after exposure to different spectra. (A) Sample immune-slot blot to quantify CPD induction following increasing doses of UVA and UVB as well as a combination of all spectra (UVB, UVA, VIS and nIR). (B) Quantification of induced CPDs after exposure towards individual spectral bands. A linear dose-dependency between UVB dose and CPD induction was found. A very weak induction was found after UVA exposure also (see Supplementary Fig. 1). (C) As in (B) but for all possible combination of the four spectral bands. The dashed line represents the induction by UVB only, while the dotted line represents the induction by UVA only, as shown in Fig. 1B. (D) Removal of CPDs from genomic DNA was measured by immuno-slot blot. Example showing two typical slot blots. (E) Measurements of CPD removal induced by either UVB (pink) or UVA (orange) exposure. The resulting intensities were normalized to the intensities directly after exposure (time 0) and fitted with a single exponential decay function. (F) Analogue to (C) the CPD removal after the exposure to combined spectra is shown. The dashed black line again represents the exponential decay fit function from (E) for UVB and the dotted for UVA respectively. The plotted values represent the mean of at least 3 independent measurements; the error bars represent the standard error of the mean. (G) Measuring CPD removal by flow cytometry. The gating schema is based on forward (FSC) scatter and side scatter (SSC), followed by gating for single cells based on the DNA quantification. From the resulting DNA content histogram only the G1 cell equivalent was used for quantification. (H) Quantification of CPD levels for either UVB alone or the complete spectrum (UVB, UVA, VIS, nIR). Datapoints represent mean values of at least three replicates. Error bars represent the standard error of the mean. Decay curves were fitted with a single exponential function. (I) Sample images of the comet assay. Shown are comets from untreated controls, UVB irradiated cells directly and 8 h after irradiation, and cells irradiated with the combination of UVB and nIR directly and 8 h post irradiation. The lysed cells were incubated with T4 endo VII endonuclease to convert CPDs to strand breaks. (J) Quantification of the comet assay. The comets were analysed in terms of DNA in tail and the residual CPDs were quantified as migrated DNA. Each datapoint represents the mean of means from three biological replicates with at least 50 scored comets per slide. Error bars are the standard error of the mean.