PREDATION BY THE TOXIC DINOFLAGELLATE DINOPHYSIS FORTII ON THE CILIATE MYRIONECTA RUBRA AND OBSERVATION OF SEQUESTRATION OF CILIATE CHLOROPLASTS 1
PREDATION BY THE TOXIC DINOFLAGELLATE DINOPHYSIS FORTII ON THE CILIATE MYRIONECTA RUBRA AND OBSERVATION OF SEQUESTRATION OF CILIATE CHLOROPLASTS 1
复制标题
有毒甲藻 Dinophysis Fortii 对纤毛虫红色 Myrionecta rubra 的捕食及纤毛虫叶绿体的封存观察 1
作者：
S. Nagai;Goh Nitshitani;Y. Tomaru;S. Sakiyama;T. Kamiyama
这是有毒甲藻Dinophysis fortii Pavill繁殖的首次报道。在实验室条件下，取食与隐芽文昌鱼(Teleaulax inioxeia(W.Conrad)D.R.A.Hill)共同生长的海洋纤毛虫Myrionecta rubra。相比之下，福州石杉的生长速度有所下降。在没有纤毛虫或仅有文昌鱼作为猎物的情况下，观察到小细胞的形成，这表明东方刺蛾不能利用文昌鱼作为猎物。在对摄食纤毛虫猎物的福氏扇贝细胞进行的透射电子显微镜观察中，可见发育良好的叶绿体(长5-12 μm)，多数叶绿体中通常排列有3个类囊体体，但有时也能观察到有2个类囊体体。在饥饿4 周的细胞中，叶绿体数量减少，大的叶绿体消失，仅有少量的小叶绿体(长度为0.5~2 μm)残留在边缘区域。在观察赤潮藻摄取的叶绿体的隔离过程中，在捕获赤潮藻后15 分钟内，观察到几乎所有的叶绿体都被掺入其中，而其他大部分细胞内容物仍保留在赤潮藻细胞中。此后，被摄取的叶绿体被证实向边缘区域分散，这表明红豆杉的叶绿体在摄取其他细胞内容物之前被摄取并分散在福氏沼虾细胞中，以防止它们被食物液泡消化。被摄取的叶绿体也可以起到盗浆体的作用。
This is the first report of the propagation of the toxic dinoflagellate Dinophysis fortii Pavill. under laboratory conditions when fed on the marine ciliate Myrionecta rubra grown with the cryptophyte Teleaulax amphioxeia (W. Conrad) D. R. A. Hill. In contrast, reduced growth of D. fortii (max. of 3–4 divisions) and formation of small cells were observed in the absence of the ciliate or when provided with T. amphioxeia only as prey, showing that D. fortii cannot utilize T. amphioxeia as prey. In the TEM observation of D. fortii cells, which had fully fed on the ciliate prey, well‐developed chloroplasts (5–12 μm in length) were seen and three thylakoids were usually arranged in most of the chloroplasts observed, but chloroplasts having two thylakoids were sometimes confirmed. In cells starved for 4 weeks, decrease of chloroplast numbers and disappearance of large chloroplasts were observed, and only a few small chloroplasts (0.5–2 μm in length) remained in the marginal regions. In the observation of the sequestration process of the chloroplasts ingested from M. rubra by D. fortii, within 15 min after D. fortii captured M. rubra, incorporation of almost all of the chloroplasts was observed, while most of the other cell contents still remained in the M. rubra cell. After that, dispersion of the ingested chloroplasts toward the marginal regions was confirmed, suggesting that chloroplasts of M. rubra are ingested and dispersed in D. fortii cells in advance of the ingestion of the other cell contents to prevent them from being digested in food vacuoles. The ingested chloroplasts can also function as kleptoplastids.