The characteristics of the connections and associated microtubules of kinetosomes in adoral membranelles ( AM) and right marginal cirri ( RMC ) of a urostylid ciliate Pseudourostyla cristata were observed by using transmission electron microscope. Kinetosomes of each row in a membranelle were linked up by anterior connection and posterior connection, and kinetosomes of two adjacent rows in a membranelle were connected with right transverse connection and left transverse connection at the proximal level. The associated microtubules extending from kinetosomes of AM were complex: the microtubule bundles of adjacent membranelles intersected in V?shape, and some microtubule bundles connected with submembranellar fibers. The base associated microtubules of RMC contained anterior longitudinal microtubules, posterior longitudinal microtubules, kinetodesmal fibril and linear microtubular arrays. Kinetosomes of RMC surrounded by fibrillar cirral basket were connected with two transverse connections, one is oblique connection and the other is longitudinal connection at the distal level. The linear microtubular arrays and kinetosomal connections of RMC of P. cristata were similar with those of the other studied urostylid, Pseudokeronopsis carnea, but different from those of oxytrichid ciliates. The study not only enriched ultrastructure data of urostylid ciliates at the kinetosomal level, but also further confirmed the specificity of organelle ultrastructure amongcertain taxons. Additionally, it provided some new information for understanding the complexity of cellular structure and the systematic of the hypotrichous ciliates.%应用透射电镜研究冠突伪尾柱虫(Pseudourostyla cristata)口围带和缘棘毛基体的超微结构.结果发现,口围带小膜基体列的基体间通过前连接和后连接相连,基体列间相邻基体在基体近端通过左横连接和右横连接相连.口围带小膜的基体附属微管较复杂,相邻小膜之间的微管束汇聚呈"V"形,基体亦发出微管与膜下微管相联系.右缘棘毛的基体被围棘纤维篮包围,周围有前纵微管、后纵微管、动纤丝和线性微管阵;基体远端处通过2根横向连接、1根斜向连接和1根纵向连接相互连接起来.本文首次报道了冠突伪尾柱虫口围带的基体间连接,同时揭示了该种缘棘毛的线性微管阵列结构和基体间的连接方式与尾柱类的肉色伪角毛虫一致,而与其他尖毛类纤毛虫差异较大.
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