硒对钝顶螺旋藻氧化损伤的拮抗作用的光谱学特性及机制

研究了亚硒酸钠预处理对H2O2氧化胁迫下钝顶螺旋藻(Spirulina platensis)的生长、藻丝体形态、谱学特性以及细胞内活性氧(ROS)水平的影响,探究硒拮抗氧化胁迫保护螺旋藻的机制。结果显示,H2O2氧化胁迫明显抑制螺旋藻的生长,藻丝体严重受损,可见光吸收440nm峰增强,620和680nm峰降低;荧光发射和激发光谱特征峰强度明显降低,藻胆蛋白特征发射峰由660nm蓝移至650nm;红外光谱透射峰没有发生位移,蛋白质和多肽的特征谱带酰胺Ⅰ带和酰胺Ⅱ带相对强度降低;细胞内ROS相对含量显著性升高。硒预处理24h呈剂量效应地减轻由H2O2胁迫引起的氧化损伤,有效地抑制胞内ROS的过度累积,提高螺旋藻的抗氧化能力,缓解了氧化胁迫对光能捕获和传递等重要生理功能的影响。

Spectrometric characteristics and underlying mechanisms of protective effects of selenium on Spirulina platensis against oxidative stress

To investigate the possibility and the underlying mechanisms of sodium selenite as antagonist for oxidative stress, the authors examined the effects of pretreatment with selenium on the growth, morphology, spectrometric characteristics and content of reactive oxygen species (ROS) in Spirulina platensis (S. platensis) exposed to H2O2 stress for 24 h in the present study. The results showed that H2O2 induced obvious inhibition of growth and serious morphological damage. The intensity of absorbance peak at 440 nm increased, whereas the peaks at 620 and 680 nm decreased after exposed to H2O2. The emission and excitation spectrum of S. platensis decreased dramatically after H2O2 treatment, and the emission peak from phycocyanin exhibited blue-shift from 660 to 650 nm. The results of FTIR analysis showed that the positions of transmission peaks had no shift, but the relative intensity of characteristic bands from protein and polypeptides including amide I and amide II decreased. Furthermore, the intracellular ROS generation in S. platensis increased significantly in response to H2O2 treatment. In contrast, pretreatments of the cells with selenium for 24 h significantly prevented the H2O2-induced oxidative damages in a dose-dependent manner. Taken together, our results indicate that pretreatments with selenium could prevent ROS overproduction in S. platensis and improve its antioxidant ability. Moreover, selenium could also reduce the effects of free radicals on energy harvest and energy transfer in S. platensis that play vital roles in its photosynthesis.