Lindholm T, Lindroos P, Mörk A C
Department of Biology, Abo Akademi, Finland.
Biosystems. 1988;21(2):141-9. doi: 10.1016/0303-2647(88)90007-x.
New cellular structures, bifurcated oral tentacles, were observed in many specimens of the photosynthetic ciliate Mesodinium rubrum from the northern Baltic Sea. Cross-sections of tentacles revealed rings (cylinders) of 14 microtubules with spokes. The number of microtubules per ring decreased from 14 to 12 or 11 inside the cell but no true kinetosomes were detected. These "micro-rings" were often associated with extrusomes and the tentacle tips consisted of extrusomes. A nucleus of a symbiotic alga was present, surrounded by algal cytoplasm containing plastids and delimited from the ciliate cytoplasm by two membranes. Each plastid was bounded by four membranes and was associated with one nucleomorph, suggesting a symbiotic origin as a cryptophyte. The unique symbiotic organization and the organelles of 14 microtubules make Mesodinium rubrum an organism of unusual evolutionary interest.
在来自波罗的海北部的许多光合纤毛虫红色中缢虫标本中观察到了新的细胞结构——分叉的口触手。触手的横截面显示有由带有辐条的14根微管组成的环（圆柱体）。每个环的微管数量在细胞内部从14根减少到12根或11根，但未检测到真正的动基体。这些“微环”通常与刺丝泡相关，触手尖端由刺丝泡组成。存在一个共生藻类的细胞核，被含有质体的藻类细胞质包围，并通过两层膜与纤毛虫细胞质分隔开。每个质体由四层膜界定，并与一个核形体相关联，这表明其作为隐藻具有共生起源。独特的共生组织和14根微管的细胞器使红色中缢虫成为一种具有特殊进化意义的生物。
