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| Watoh, Tomoko; Sekida, Satoko; Yamamoto, Keisuke; Kida, Akemi; Matsuoka, Tatsuomi. |
| Morphological changes during resting cyst formation (encystment) of Colpoda cucullus were examined. At 1 hr after encystment induction, a number of vesicles containing the electron-dense and toluidine blue (TB) positive materials were fused with large vacuoles to excrete the contents, and the vacuoles opened to the extracellular space to excrete. In this stage, the rounded precystic cells were surrounded by the first-synthesized cyst wall layer (L1 layer), and the cilia were resorbed inside the L1 layer. Thereafter (1-2 hr), a secondary layer (L2 layer) was formed and subsequently a deeply TB stained substance was diffused into the space between the plasma membrane and L2 layer. At 3-6 hr, numerous endoplasmic reticula (ER) associated with ribosomes... |
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Palavras-chave: Colpoda; Encystment; Cyst wall; Toluidine blue. |
| Ano: 2005 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/148 |
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| Yamamoto, Keisuke; Takada, Yuichi; Kida, Akemi; Akematsu, Takahiko; Kotsuki, Hiyoshizo; Matsuoka, Tatsuomi. |
| In the absence of O2, the step-up photophobic response of Blepharisma japonicum is suppressed. To evaluate the possibility that reactivated oxygen species (ROS) produced by blepharismin photosensitization are involved in the primary transduction for the step-up photophobic response of B. japonicum, the effects of OH radical scavengers and the singlet oxygen quencher on the photophobic response were examined. The reagents used in the present assays hardly suppressed the step-up photophobic response, even though OH radical scavengers were rescued from the photodynamic killing of the cells. Alternatively, in the presence of an electron acceptor, the latency of the step-up photophobic response was prolonged. In addition, oxyblepharismin fluorescence was... |
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Palavras-chave: Blepharisma; Phototransduction; Reactivated oxygen species. |
| Ano: 2007 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/1049 |
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| Maeda, Hajime; Akematsu, Takahiko; Fukui, Risa; Matsuoka, Tatsuomi. |
| The resting cysts of Colpoda cucullus were resistant to not only drying, but high and low temperatures. The critical temperatures for the survival of wet cysts ranged from 40 oC (3-hr exposure) to 45 oC (10-min exposure), and those of the dried cysts ranged from 80 oC (3-hr exposure) to 100 oC (30-min exposure). Frozen (-30 oC, 3 hr) and remelted wet cysts also survived. Ca2+-induced resting cysts excysted when the external Ca2+ was removed. However, the excystment-inducing effect by Ca2+ removal was canceled by the addition of cations such as Na+, K+, and Mg2+ in the surrounding medium. When the mature cysts transformed in a diluted buffer without any other salts were temporally exposed to Ca2+ and subsequently resuspended in the buffer without Ca2+,... |
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Palavras-chave: Colpoda; Encystment; Excystment; Resistance to temperature; Ca2+; Porphyrins. |
| Ano: 2005 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/146 |
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