Department of Biology, Chungnam National University, Deajeon 34134, Republic of Korea; LOHABE, Department of Oceanography, Chonnam National University, Gwangju 61186, Republic of Korea.
Department of Oceanography, Kunsan National University, Kunsan 54150, Republic of Korea; Ocean Climate and Ecology Research Division, National Institute of Fisheries Science, Busan 46083, Republic of Korea.
Harmful Algae. 2016 Nov;59:19-30. doi: 10.1016/j.hal.2016.09.002. Epub 2016 Sep 28.
Mesodinium rubrum Lohmann is a mixotrophic ciliate and one of the best studied species exhibiting acquired phototrophy. To investigate the fate of cryptophyte organelles in the ciliate subjected to starvation, we conducted ultrastructural studies of a Korean strain of M. cf. rubrum during a 10 week starvation experiments. Ingested cells of the cryptophyte Teleaulax amphioxeia were first enveloped by ciliate membrane, and then prey organelles, including ejectisomes, flagella, basal bodies and flagellar roots, were digested. Over time, prey nuclei protruded into the cytoplasm of the ciliate, their size and volume increased, and their number decreased, suggesting that the cryptophyte nuclei likely fused with each other in the ciliate cytoplasm. At 4 weeks of starvation, M. cf. rubrum cells without cryptophyte nuclei started to appear. At 10 weeks of starvation, only two M. cf. rubrum cells still possessing a cryptophyte nucleus had relatively intact chloroplast-mitochondria complexes (CMCs), while M. cf. rubrum cells without cryptophyte nuclei had a few damaged CMCs. This is the first ultrastructural study demonstrating that cryptophyte nuclei undergo a dramatic change inside M. cf. rubrum in terms of size, shape, and number following their acquisition.
红色中缢虫（Mesodinium rubrum Lohmann）是一种混养纤毛虫，是研究获得性光养的最佳模式生物之一。为了研究在饥饿条件下隐藻细胞器在纤毛虫中的命运，我们对一种来自韩国的红色中缢虫 cf. rubrum 进行了 10 周的饥饿实验的超微结构研究。首先，被吞噬的隐藻细胞被纤毛虫膜包裹，然后猎物细胞器，包括喷出体、鞭毛、基体和鞭毛根，被消化。随着时间的推移，猎物核突入纤毛虫细胞质中，其大小和体积增加，数量减少，这表明隐藻核可能在纤毛虫细胞质中融合。在饥饿 4 周时，出现了没有隐藻核的红色中缢虫 cf. rubrum 细胞。在饥饿 10 周时，只有两个仍然含有隐藻核的红色中缢虫 cf. rubrum 细胞具有相对完整的叶绿体-线粒体复合物（CMCs），而没有隐藻核的红色中缢虫 cf. rubrum 细胞只有少数受损的 CMCs。这是首次超微结构研究表明，隐藻核在被吞噬后，其大小、形状和数量在红色中缢虫 cf. rubrum 内发生了显著变化。
