Bidirectional transport by ciliated epithelia : mechanism and implications

本研究的目的是调查在棘皮动物的磁长石中观察到的双向转运是否可能是纤毛上皮的固有特性。它也旨在澄清这一现象的生物学意义，特别是从可能的逆流交换机制的观点。利用胶体碳、聚苯乙烯微球和水溶性荧光染料磺胺- 101，主要研究了海胆红闪石的分离孔管中颗粒和水的迁移。在倒置差示干涉对比和荧光显微镜下观察，用CCD摄像机记录。结果表明，水分主要沿纤毛恢复行程方向输送，而颗粒物主要沿纤毛有效行程方向输送。因此，似乎有一种选择机制，可能是基于被输送的颗粒的大小。获得了红闪石孔管中纤毛周围微观区域流速分布的基本数据。初步实验也使用其他纤毛上皮进行类似的分析。

The aim of this study was to investigate the possibility that bidirectiona1 transport that had been observed in the madreporite of echinoderms is an inherent property of ciliated epithelia in general. It also aimed to clarify the biological implications of this phenomenon , especially from the viewpoint of possible counter-current exchange mechanism. The transport of particles and water was studied mainly in isolated pore tubes of the sea urchin madreporite using colloidal carbon, polystyrene microbeads, and sulforhodamine 101, a water-soluble fluorescent dye. Observations were made under an inverted differential interference contrast and fluorescence microscope recording with a CCD video camera. The results showed that water is transported predominantly in the direction of the recovery stroke of the cilia while particulate matter was transported in the direction of the effective stroke. Thus, there seems to be a selective mechanism probably based on the size of the particle being transported. Basic data were obtained on the distribution of flow rate in the microscopic domains surrounding the cilia within the pore canals of the madreporite. Preliminary experiments were also carried out using other ciliated epithelia for similar analyses.