Salehi-Ashtiani K, Antipa G A
Department of Biology, San Francisco State University, California 94132, USA.
J Eukaryot Microbiol. 1997 Sep-Oct;44(5):471-9. doi: 10.1111/j.1550-7408.1997.tb05726.x.
Mytilophilus pacificae is an endocommensal ciliate found in the mantle cavity of the Pacific Coast mussel Mytilus californianus. In this paper we report our findings on pellicular organization of this species. Transmission and scanning electron microscope examination of the somatic cortex revealed that a number of different types of kinetids, i.e. monokinetids, dikinetids, and polykinetids are found in the locomotor cortex. The type and distribution of the kinetids are described. Surprisingly, the locomotor region was found to be highly variable among individuals with respect to its kinetid distribution; each cell appears to have its own characteristic kinetid pattern. Some cells have mostly monokinetids and dikinetids in their locomotor cortex, while others may have dikinetids and polykinetids but very few monokinetids. In contrast to the locomotor region, the thigmotactic field (a region specialized for attachment) is exclusively composed of dikinetids and shows no heterogeneity. The finding of ultrastructural variability in the locomotor cortex was unexpected since, in the view of the structural conservatism hypothesis, the somatic cortex is seen as a "stable" element. These observations raise new questions with regard to cortical pattern formation in this organism.
太平洋贻贝嗜贻虫是一种内共生纤毛虫，发现于太平洋海岸贻贝加州贻贝的外套腔中。在本文中，我们报告了关于该物种表膜组织的研究结果。对体细胞皮层的透射电子显微镜和扫描电子显微镜检查显示，在运动皮层中发现了许多不同类型的动质体，即单动质体、双动质体和多动质体。描述了动质体的类型和分布。令人惊讶的是，在个体之间，运动区域的动质体分布差异很大；每个细胞似乎都有其独特的动质体模式。一些细胞的运动皮层主要是单动质体和双动质体，而另一些细胞可能有双动质体和多动质体，但单动质体很少。与运动区域不同，趋触性区域（一个专门用于附着的区域）完全由双动质体组成，没有异质性。在运动皮层中发现超微结构的变异性是出乎意料的，因为根据结构保守性假说，体细胞皮层被视为一个“稳定”的元素。这些观察结果引发了关于该生物体皮层模式形成的新问题。
