Fig. 2

SPI caused algal structure degradation and exhibited oxidative activities both in vivo and in vitro. A TEM observation of the algal cells with different treatment. N, nuclear. W, cell wall. Ch, chloroplast. F, fungal cell. B Subset of the annotated and differentially expressed genes following SPI treatment. C Oxidative activities of the SPI determined by thiobarbituric acid (TBA) assay. D Lipid peroxidation in algal cells treated with SPI. E Hydroxyl radical detection. For the biochemical assays, the Fenton reagents (0.83 mM ferrous ions and 30 mM hydrogen peroxide) and BG11 medium was used as positive and negative control, respectively. The quantitative data were presented as mean ± S.D. (n = 3). **, p < 0.01 (Student’s t test). Scale bar, 5 μm