Ryss A Yu
Parazitologiia. 2017 Jan-Feb;51(1):57-67.
The simplest modification of the dynamic extraction method using cottonwool filter based on the Baermann funnel principle, is described. This modification excludes the funnel because a great share of Sticky worms attach to sloping walls of a funnel and thus do not reach the collector Eppendorf tube. But the main principle of the Baermann funnel is used, I. e. sinking down of actively moving heavy narrow bodies via wide holes of filter and thus separating the active worms from passive non-Brownian moving substrate particles, which do not pass the filter and remain above it. This principle is illustrated because it has never been described before. In the proposed modification any sloping walls in the extraction paths are excluded and thus the probability to attach sticky nemotodes to walls is also excluded; only cylindrical equipment with abrupt vertical walls is used; procedures are extremely simplified to be user-friendly for beginners: only filter (cotton pads), Eppendorf tubes, plastic glasses and narrow PVC tubing are applied. The new simplified modification allows one to collect nematodes by non-professional workers, e. g. in Polar expeditions without microscopic study of results. As an addition, an efficient method to maintain extracted nematodes alive is proposed, using the "effect of water film" in foam rubber inside the Eppendorf tube. To maintain nematodes alive during several months it is recommended to suppress bacteria via addition of 0.2-0.4% formaldehyde solution and then keep the tube with nematodes in a refrigerator.
本文描述了基于贝尔曼漏斗原理,使用棉絮过滤器对动态提取方法进行的最简单改进。这种改进不再使用漏斗,因为很大一部分粘性蠕虫会附着在漏斗的倾斜壁上,从而无法到达收集器(艾本德管)。但仍采用了贝尔曼漏斗的主要原理,即通过过滤器的宽孔使活跃移动的重窄体下沉,从而将活跃的蠕虫与被动的非布朗运动的基质颗粒分离,这些颗粒不会通过过滤器并留在其上方。阐述这一原理是因为此前从未有过相关描述。在所提出的改进方法中,提取路径中不再有任何倾斜壁,因此也排除了粘性线虫附着在壁上的可能性;仅使用具有陡峭垂直壁的圆柱形设备;步骤极大简化,对初学者来说非常方便:仅使用过滤器(棉垫)、艾本德管、塑料杯和窄PVC管。这种新的简化改进方法使非专业人员也能够收集线虫,例如在极地探险中无需对结果进行显微镜研究。此外,还提出了一种利用艾本德管内泡沫橡胶中的“水膜效应”来有效维持提取的线虫存活状态的方法。为使线虫存活数月,建议加入0.2 - 0.4%的甲醛溶液抑制细菌生长,然后将装有线虫的管子保存在冰箱中。