Characteristics of the Digestive Vacuole Membrane of the Alga-Bearing Ciliate Paramecium bursaria
Characteristics of the Digestive Vacuole Membrane of the Alga-Bearing Ciliate Paramecium bursaria
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DOI：
10.1016/j.protis.2011.10.004
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发表时间：
2012-07-01
期刊：
影响因子：
2.5
通讯作者：
Fujishima, Masahiro
中科院分区：
文献类型：
--
作者：
Kodama, Yuuki;Fujishima, Masahiro
草履虫细胞内共生小球藻。在它们的细胞质中。为了与无藻的囊藻建立内共生，共生藻必须离开消化泡（DV），通过DV膜的出芽出现在细胞质中。这种出芽不仅由完整的藻类诱导，而且由煮沸或固定的藻类诱导。然而，当食用细菌或印度墨水被摄入到DV中时，这种出芽并没有被诱导。这些结果提高了绿背飞虱能够识别DVs中内容物大小的可能性。为了阐明这种可能性，将不同直径的微珠与无藻的P. bursaria混合，并追踪它们的命运。直径为0.20 μ m的微珠不能诱导DV出芽。直径为0.80 μ m的微珠在混合后3分钟产生直径为5-10 μ m的DV;然后DV破碎并变成直径为2-5 μ m的空泡，直到混合后3小时。每个直径大于3.00 μ m的微珠诱导类似于共生小球藻的出芽。这些观察结果表明，DV出芽的诱导取决于DV内容物的大小。动力蛋白抑制剂Dynasore对DV出芽有明显的抑制作用，提示动力蛋白可能参与DV出芽过程。(C)2011年Elsevier GmbH。All rights reserved.
Cells of the ciliate Paramecium bursaria harbor symbiotic Chlorella spp. in their cytoplasm. To establish endosymbiosis with alga-free P. bursaria, symbiotic algae must leave the digestive vacuole (DV) to appear in the cytoplasm by budding of the DV membrane. This budding was induced not only by intact algae but also by boiled or fixed algae. However, this budding was not induced when food bacteria or India ink were ingested into the DVs. These results raise the possibility that P. bursaria can recognize sizes of the contents in the DVs. To elucidate this possibility, microbeads with various diameters were mixed with alga-free P. bursaria and traced their fate. Microbeads with 0.20 mu m diameter did not induce budding of the DVs. Microbeads with 0.80 mu m diameter produced DVs of 5-10 mu m diameter at 3 min after mixing; then the DVs fragmented and became vacuoles of 2-5 mu m diameter until 3 h after mixing. Each microbead with a diameter larger than 3.00 mu m induced budding similarly to symbiotic Chlorella. These observations reveal that induction of DV budding depends on the size of the contents in the DVs. Dynasore, a dynamin inhibitor, greatly inhibited DV budding, suggesting that dynamin might be involved in DV budding. (C) 2011 Elsevier GmbH. All rights reserved.