title: The fate of cryptophyte cell organelles in the ciliate Mesodinium cf. rubrum subjected to starvation.
abstract: 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.
authors.affiliation: Department of Biology, Chungnam National University, Deajeon 34134, Republic of Korea; LOHABE, Department of Oceanography, Chonnam National University, Gwangju 61186, Republic of Korea.
authors.forename: Seung Won
authors.initials: SW
authors.lastname: Nam
authors.affiliation: 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.
authors.forename: Jong Woo
authors.initials: JW
authors.lastname: Park
authors.affiliation: Department of Oceanography, Kunsan National University, Kunsan 54150, Republic of Korea.
authors.forename: Wonho
authors.initials: W
authors.lastname: Yih
authors.affiliation: LOHABE, Department of Oceanography, Chonnam National University, Gwangju 61186, Republic of Korea. Electronic address: mpark@chonnam.ac.kr.
authors.forename: Myung Gil
authors.initials: MG
authors.lastname: Park
authors.affiliation: Department of Biology, Chungnam National University, Deajeon 34134, Republic of Korea. Electronic address: shinw@cnu.ac.kr.
authors.forename: Woongghi
authors.initials: W
authors.lastname: Shin
mesh_terms: D016798:Ciliophora / Q000166:cytology / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D044785:Cryptophyta / Q000166:cytology / Q000648:ultrastructure; D009747:Nutritional Physiological Phenomena; D015388:Organelles / Q000378:metabolism / Q000648:ultrastructure
keywords: Acquired phototrophy; Mesodinium cf. rubrum; Nuclear fusion; Nucleus; Teleaulax amphioxeia