Fig. 3: Phenotype of the gPCEM strain.

A The growth curves of the WT and gPCEM strain in BG11 medium in the presence of 1 mM theophylline (TP) and 0.3 μM Cu²⁺ under the indicated light conditions. LL: low light; SL: standard light; HL: high light. The initial concentration measured at OD₇₅₀ for each strain was 0.05. All values are shown as mean ± standard deviation, calculated from triplicate data. B Micrographs of Anabaena filaments of the WT (wild type) and the gPCEM strain in the indicated days and light conditions. Scale bars: 10 µm. -: without inducer; +: with inducer. C Statistical analysis of cell length and width of the WT (wild type) and the gPCEM strain at the indicated days after induction under light conditions. 300 cells of each strain from three independent experiments were measured. The mean value was indicated with the numbers. The Student’s t-test examined the differences between the 0 days and the other days. Results were considered significant at *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001, ns: no significance.