Department of Physics, Harvard University, 17 Oxford Street, Cambridge, MA 02138, USA.
Proc Natl Acad Sci U S A. 2009 Nov 24;106(47):20093-6. doi: 10.1073/pnas.0904036106. Epub 2009 Nov 10.
Caenorhabditis elegans is a filter feeder: it draws bacteria suspended in liquid into its pharynx, traps the bacteria, and ejects the liquid. How pharyngeal pumping simultaneously transports and filters food particles has been poorly understood. Here, we use high-speed video microscopy to define the detailed workings of pharyngeal mechanics. The buccal cavity and metastomal flaps regulate the flow of dense bacterial suspensions and exclude excessively large particles from entering the pharynx. A complex sequence of contractions and relaxations transports food particles in two successive trap stages before passage into the terminal bulb and intestine. Filtering occurs at each trap as bacteria are concentrated in the central lumen while fluids are expelled radially through three apical channels. Experiments with microspheres show that the C. elegans pharynx, in combination with the buccal cavity, is tuned to specifically catch and transport particles of a size range corresponding to most soil bacteria.
它将悬浮在液体中的细菌吸入咽部，捕获细菌，然后排出液体。然而，关于咽部抽吸如何同时输送和过滤食物颗粒，人们对此知之甚少。在这里，我们使用高速视频显微镜来定义咽部力学的详细工作原理。口腔和侧瓣调节着密集细菌悬浮液的流动，并阻止过大的颗粒进入咽部。在食物颗粒进入终球和肠道之前，一系列复杂的收缩和松弛运动将其在两个连续的捕获阶段中运输。在每个捕获阶段都会发生过滤，因为细菌在中央腔中浓缩，而液体则通过三个顶端通道径向排出。通过使用微球体进行的实验表明，秀丽隐杆线虫的咽部与口腔一起，被调整为专门捕获和运输与大多数土壤细菌大小相对应的颗粒。
