Laval-Peuto M, Febvre M
Biosystems. 1986;19(2):137-58. doi: 10.1016/0303-2647(86)90026-2.
Many hundreds of isolated plastids, in a good state of preservation in their living host, the planktonic ciliate Tontonia appendiculariformis (Oligotrichina), have been studied by electron microscopy. These distinctive plastids, located at the periphery of the host's body, which do not belong to complete symbiotic algae, are described in detail. All are bounded by three membranes. Although degenerating plastids were observed none were ever seen in division. Their possible origin, the significance of the three plastid membranes, and the degree of symbiosis established are discussed. From their organization, these plastids may have originated from several species of chromophyte algae, such as dinophyceae, Prymnesiophyceae, and Bacillariophyceae or Chrysophyceae. Because of their absence of division and of their possible degeneration, they are probably not integrated genetically. However, they appear to survive for some time and to remain functional. There is evidence that the outermost third plastid membrane arises from the host ciliate. Finally, hypotheses are proposed to explain the incorporation of the plastids into the ciliate, and their possible role in building cortical polysaccharide plates.
通过电子显微镜对数百个分离的质体进行了研究，这些质体保存在它们的活体宿主——浮游纤毛虫类的附枝汤氏虫（寡毛纲）中，保存状态良好。详细描述了这些位于宿主身体周边、不属于完整共生藻类的独特质体。所有质体都由三层膜包被。虽然观察到了退化的质体，但从未见过它们分裂。讨论了它们可能的起源、三层质体膜的意义以及所建立的共生程度。从它们的结构来看，这些质体可能起源于几种色藻类，如甲藻纲、定鞭藻纲、硅藻纲或金藻纲。由于它们不分裂且可能退化，它们可能在基因上没有整合。然而，它们似乎能存活一段时间并保持功能。有证据表明，最外层的第三层质体膜起源于宿主纤毛虫。最后，提出了一些假设来解释质体被整合到纤毛虫中的过程，以及它们在构建皮层多糖板中可能发挥的作用。
