Bidirectional transport by ciliated epithelia : mechanism and implications

本研究的目的是调查的可能性，双向运输已观察到棘皮动物madreporite是一个固有的纤毛上皮细胞的一般属性。它还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角度。研究了主要是在孤立的海胆madreporite使用胶体碳，聚苯乙烯微珠，和磺酰罗丹明101，水溶性荧光染料孔管的颗粒和水的运输。在倒置微分干涉对比和用CCD摄像机记录的荧光显微镜下进行观察。结果表明，水主要是在纤毛的恢复行程的方向上传输，而颗粒物的有效行程的方向上传输。因此，似乎有一个选择性的机制，可能是基于被传输的颗粒的大小。获得了madreporite孔道内纤毛周围微观域流速分布的基本数据。还使用其他纤毛上皮进行了初步实验以进行类似的分析。

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.