Near-coronal fluid flow patterns and food cell manipulation in the rotifer Brachionus calyciflorus
Near-coronal fluid flow patterns and food cell manipulation in the rotifer Brachionus calyciflorus
复制标题
萼花轮虫的近冠状流体流动模式和食物细胞操纵
作者：
P. Starkweather
萼花臂尾轮虫能够根据轮虫在进食时遇到的悬浮颗粒的总体密度（数量为µl−1）和大小来区别地捕获或偏转潜在的食物细胞。这已被证明与假轮结构的行为调节相关，主要是由复合纤毛（cirri）的大内侧簇。当假转子纤毛横向延伸时，推断出的流体流动路径显示，只有位于冠状盘中心25 µm处的细胞会被摄入。当假转子纤毛形成中间取向的屏障时，流体流被引导远离假转子和中央冠，在被限制的动物前方高达70 µm处的效果明显。B的所有区域中的流体流动。calyciflorus corona的雷诺数（Re）非常低，计算值总是小于10−1。因此，从摄食电流中去除细胞可能不是由于筛分，而更可能是由于单个纤毛元件对颗粒的直接拦截。某些大细胞--如纤细裸藻--在假转子间隙内滞留长达500毫秒，这对B来说是足够的时间。calyciflorus来评估这种或其他潜在食物的物理和化学特性。
Brachionus calyciflorus is able to differentially capture or deflect potential food cells depending on the overall density (numbers µl−1) and size of suspended particles the rotifer encounters while feeding. This has been shown to correlate with behavioral regulation of pseudotrochal structures, and primarily by large medial tufts of compound cilia (cirri). When pseudotrochal cirri are extended laterally, inferred fluid flow pathlines show that only cells in the central 25 µm of the coronal disk are subject to ingestion. When pseudotrochal cirri form medially-oriented screens, fluid flow is directed away from the pseudotrochas and central corona, an effect apparent up to 70 µm in front of a restrained animal. Fluid flow in all areas of the B. calyciflorus corona is at very low Reynolds Number (Re), with calculated values always less than 10−1. Accordingly, removal of cells from feeding currents probably is not due to sieving but is more likely due to direct interception of particles by individual ciliary elements. Certain large cells — such as Euglena gracilis — are retained in the inner pseudotrochal space for up to 500 msec, ample time for B. calyciflorus to assess the physical and chemical characteristics of this or other potential foods.