Department of Microbiology, Immunology, and Tropical Medicine, Ross Hall, 2300 I Street NW, The George Washington University, Washington, DC 20052.
J Parasitol. 2022 Jul 1;108(4):403-407. doi: 10.1645/22-47.
The Baermann filter method is a long-standing, simple technique for recovering nematodes from soil and charcoal coprocultures. Material containing the nematodes is placed on a mesh screen lined with several layers of tissue paper or cheesecloth, and the screen is placed in the mouth of the funnel. Rubber tubing attached to the funnel stem is clamped, and water is added to submerge the material. The filtration material allows the nematodes to swim through while holding back the substrate. Over time the nematodes settle at the clamp in the tubing. After several hours, the clamp is opened and water containing the nematodes is collected. Although recovery of the nematodes is efficient, they are often contaminated with soil or charcoal debris, requiring a secondary cleaning by sedimentation or filtration. Described here is a small, simplified version of the Baermann apparatus that can be used as a secondary cleaning device. The "mini-Baermann" is constructed from materials commonly found in the laboratory. Experiments using infective larvae of 3 nematode species demonstrated that the majority of the larvae applied to the device are collected within 2 hr, and nearly all by 4 hr. Dead larvae fail to pass through the filter and do not significantly impact the passage of living larvae. In addition to removing debris from nematode suspensions, this device can rapidly and efficiently separate living, motile larvae from dead larvae.
贝曼氏滤器法是一种从土壤和木炭共培养物中回收线虫的古老而简单的技术。将含有线虫的材料放在带有几层纸巾或粗棉布的网筛上，然后将网筛放在漏斗的口中。连接到漏斗柄的橡胶管被夹住，然后加水淹没材料。过滤材料允许线虫游过，同时阻挡基质。随着时间的推移，线虫会在管中的夹具处沉淀。几个小时后，打开夹具，收集含有线虫的水。尽管线虫的回收率很高，但它们经常被土壤或木炭碎片污染，需要通过沉淀或过滤进行二次清洗。这里介绍的是一种小型简化版的贝曼氏仪器，可用作二次清洗装置。“迷你贝曼氏”由实验室中常见的材料制成。使用 3 种线虫感染幼虫的实验表明，大多数应用于该装置的幼虫在 2 小时内被收集，几乎所有幼虫在 4 小时内被收集。死亡的幼虫无法通过过滤器，并且不会显著影响活幼虫的通过。除了从线虫悬浮液中去除碎片外，该装置还可以快速有效地将活动的、能动的幼虫与死亡的幼虫分离。
