Research Center for Harmful Algae and Aquatic Environment, Jinan University, Guangzhou 510632, China.
Mar Pollut Bull. 2011 Dec;62(12):2692-9. doi: 10.1016/j.marpolbul.2011.09.021. Epub 2011 Oct 20.
Karenia mikimotoi is one of the most important harmful algal species in the Chinese coastal waters, and which produce hemolytic toxins and ichthyotoxins, resulting in devastating economic losses. Previous studies demonstrated that the increase of nitrate concentration could promote the growth and reproduction of K. mikimotoi. However, the intrinsic mechanisms regarding the effects of nitrate on the K. mikimotoi photosynthesis, nucleic acid replication and differential protein expression remain to be elucidated. Our study demonstrated that nitrate stress inhibited growth of K. mikimotoi (p<0.01). Algal chlorophyll fluorescence intensity varied slightly while algal cell cycle succession was significantly retarded by nitrate stress (p<0.05). Sixteen proteins were detected only in nitrate-limited cultures which related to nitrate transport, signal transduction, amino acid metabolism, DNA repair and hemolysin manufacture. Eleven proteins were detected only in nitrate-replete sample and were related to photorespiration, reproduction and growth, assistance of protein modification, cytoskeleton stability and signal transduction. Based on analysis of differential proteomic functional annotations, we hypothesized a proteomic response mechanism of K. mikimotoi to environmental nitrate stress.
米氏凯伦藻是中国近岸海域最重要的有害赤潮藻之一，能够产生溶血毒素和鱼毒素，从而造成巨大的经济损失。先前的研究表明，硝酸盐浓度的增加可以促进米氏凯伦藻的生长和繁殖。然而，硝酸盐对米氏凯伦藻光合作用、核酸复制和差异蛋白表达影响的内在机制仍有待阐明。我们的研究表明，硝酸盐胁迫抑制了米氏凯伦藻的生长（p<0.01）。藻类叶绿素荧光强度变化不大，而硝酸盐胁迫显著延缓了藻类细胞周期的进程（p<0.05）。在硝酸盐限制培养中检测到 16 种仅存在于硝酸盐限制培养中的蛋白，这些蛋白与硝酸盐转运、信号转导、氨基酸代谢、DNA 修复和溶血素制造有关。在硝酸盐充足的样本中检测到 11 种仅存在于硝酸盐充足样本中的蛋白，与光呼吸、繁殖和生长、蛋白质修饰的辅助、细胞骨架稳定性和信号转导有关。基于差异蛋白质组学功能注释的分析，我们假设了米氏凯伦藻对环境硝酸盐胁迫的蛋白质组响应机制。
