The secretory contents of Paramecium tetraurelia trichocysts: ultrastructural--cytochemical characterization.
The secretory contents of Paramecium tetraurelia trichocysts: ultrastructural--cytochemical characterization.
复制标题
草履虫毛囊的分泌内容物：超微结构-细胞化学表征。
DOI：
--
复制
发表时间：
1984
影响因子：
3.2
通讯作者：
H. Plattner
中科院分区：
文献类型：
--
作者：
H. Kersken;R. Tiggemann;C. Westphal;H. Plattner
当草履虫毛囊在胞吐过程中经历 Ca2+ 介导的解凝时，其分泌内容物（“基质”）会膨胀 4.5 倍。与此同时，基质的周期性条带间隔从 12 nm 增加到 45-51 nm，这通过蛋白质和带负电基团的不同电子染色变得可见。最近关于分泌内容物中肌动蛋白的报道使我们研究了其在毛囊内容物扩张时的重新分布和人为吸附。为了可视化这种效果，我们使用了针对草履虫肌动蛋白的 IgG 的过氧化物酶标记的 F(ab) 片段、DNAase I-金复合物以及 F-肌动蛋白聚合的诱导。对毛囊进行原位分析以及通过密度梯度离心分离后进行分析。此外，根据当前文献报道，我们重新分析了毛囊虫内容物中是否存在钙调蛋白。为此，我们应用了三种独立的原位方法：三氟拉嗪亲和标记后的自发荧光、钙调蛋白荧光亲和标记和电子显微镜免疫细胞化学方法。所有三种方法都未能在原位揭示结构完整的毛囊的任何显着标记，尽管我们也表明排出的毛囊从培养基中贪婪地吸附钙调蛋白。根据目前的数据，我们得出结论，胞吐作用期间毛囊的解凝是由毛囊内容物中分泌蛋白的突然构象重排介导的，不涉及任何其他调节或收缩蛋白，这些蛋白仅发生在细胞质中。三囊胞内容物没有显着（如果有的话）糖基化。
The secretory contents ("matrix") of Paramecium tetraurelia trichocysts expand by a factor of 4.5 when they undergo a Ca2+-mediated decondensation in the course of exocytosis. This is paralleled by a concomitant increase in the interval of the periodic banding of the matrix from 12 nm to 45-51 nm, which becomes visible with different electron stains for proteins and negatively charged groups. Recent reports of actin in secretory contents led us to investigate its redistribution and artifactual adsorption to the trichocyst contents upon their expansion. To visualize this effect we used peroxidase-labeled F(ab) fragments from an IgG directed against Paramecium actin, a DNAase I-gold complex, and the induction of F-actin polymerization. The trichocysts were analyzed in situ as well as after isolation by density-gradient centrifugation. Additionally, in response to current reports in the literature, we reanalyzed trichocyst contents for any possible presence of calmodulin. We applied three independent in situ methods for this: autofluorescence after trifluoperazine affinity labeling, calmodulin-fluorescence affinity labeling, and an electron microscopic immunocytochemical method. All three methods failed to reveal any significant labeling of structurally intact trichocysts in situ, although we also showed that discharged trichocysts avidly adsorb calmodulin from the culture medium. From the present data we conclude that the decondensation of trichocysts during exocytosis is mediated by a sudden conformational rearrangement of secretory proteins in the trichocyst contents, without the involvement of any other regulatory or contractile proteins, which occur only in the cytoplasm. Trichocyst contents are not significantly--if at all--glycosylated.