Laboratoire des Sciences de l'Environnement Marin (LEMAR), UMR6539, Institut Universitaire Européen de la Mer (IUEM), Place Nicolas Copernic, 29280 Plouzané, France.
Microb Ecol. 2011 Nov;62(4):919-30. doi: 10.1007/s00248-011-9889-5. Epub 2011 Jul 5.
The allelopathic effects of Alexandrium minutum, a toxic dinoflagellate, on the diatom Chaetoceros neogracile were evaluated using unialgal cultures evaluated by flow cytometry (FCM) and photosynthetic-performance analysis. Using FCM, we demonstrated that red chlorophyll fluorescence, relative cell size (Forward scatter of blue laser light, FSC) and cell complexity (Side scatter, 90°-angle scatter of blue laser light, SSC) significantly and rapidly decreased in C. neogracile cells exposed to A. minutum. Cells of C. neogracile exposed to A. minutum had fewer active photosynthetic reaction centers and sharply decreased photosynthetic efficiency. These effects were intensified with advancing A. minutum batch culture age and cell density. The supernatant of A. minutum contained the majority of the putative allelopathic compounds, and the biological activity of these compounds remained active less than 9 h after release. This paper describes for the first time specific effects of allelochemicals produced by A. minutum on the photosynthetic apparatus of microalgal target cells. The biochemical composition of A. minutum allelopathic agents, however, remains unknown and still needs to be investigated.
采用流式细胞术（FCM）和光合性能分析，评估了有毒甲藻亚历山大藻对硅藻新月菱形藻的化感作用。通过 FCM，我们证明了暴露于亚历山大藻的新月菱形藻细胞的红色叶绿素荧光、相对细胞大小（蓝色激光光前向散射，FSC）和细胞复杂性（90°角散射蓝色激光光，SSC）显著且迅速降低。暴露于亚历山大藻的新月菱形藻细胞的活性光合作用反应中心较少，光合效率急剧下降。这些效应随着亚历山大藻分批培养龄期和细胞密度的增加而加剧。亚历山大藻的上清液中含有大部分假定的化感化合物，并且这些化合物在释放后不到 9 小时仍保持生物活性。本文首次描述了亚历山大藻产生的化感化合物对微藻靶细胞光合器官的特定影响。然而，亚历山大藻化感剂的生化组成仍不清楚，仍需进一步研究。
