open access

https://hdl.handle.net/2115/53640

Morphological Transition in Kleptochloroplasts after Ingestion in the Dinoflagellates Amphidinium poecilochroum and Gymnodinium aeruginosum (Dinophyceae)

英語

ultrastructure

2013-09

Elsevier gmbh, urban & fischer verlag

Protist

164(5)

622-642

The unarmoured marine dinoflagellate Amphidinium poecilochroum and the unarmoured freshwater dinoflagellate Gymnodinium aeruginosum both belonging to the same clade, are known to possess cryptomonad-derived kleptochloroplasts. Previous studies revealed that G. aeruginosum can synchronise the division of the chloroplast with its own cell division while no simultaneous division takes place in A. poecilochroum, which is interpreted to mean that state of kleptochloroplastidy in G. aeruginosum is closer to that of the initial acquisition of the 'true chloroplast' within the lineage. Although the general ultrastructure of these two species has been reported, the changes in the kleptochloroplast with time have never been followed. We observed morphological changes in kleptochloroplasts of A. poecilochroum and G. aeruginosum following the ingestion of cryptomonad cells, using light and transmission electron microscopes. In A. poecilochroum, the cryptomonad ejectosomes, mitochondria and cytoplasm were all actively transferred into digestive vacuoles within 1 h of ingestion. The chloroplasts were deformed and the cryptomonad nucleus was digested after 3 h. By contrast, in G. aeruginosum, the cryptomonad cytoplasm and nucleus were retained for 24 h following ingestion, and the chloroplast was substantially enlarged. These differences imply that the retention of the cryptomonad nucleus is important for the maintenance of the chloroplast. (c) 2013 Elsevier GmbH. All rights reserved.

学術雑誌論文

Accepted Manuscript

http://www.elsevier.com/journal-authors/policies/open-access-policies/article-posting-policy

1434-4610