Elhadidy Ahmed M, Van Dyke Michele I, Peldszus Sigrid, Huck Peter M
NSERC Chair in Water Treatment, Department of Civil and Environmental Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada.
NSERC Chair in Water Treatment, Department of Civil and Environmental Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada.
J Microbiol Methods. 2016 Nov;130:154-163. doi: 10.1016/j.mimet.2016.09.009. Epub 2016 Sep 13.
Flow cytometry is an efficient monitoring tool for rapid cell counting, and can be applied to research on water quality and treatment. In this study, a method that employs flow cytometry and a natural microbial inoculum to determine assimilable organic carbon (AOC) was adapted for use with challenging surface waters that have a high organic and particle content, and subsequently applied in a long term river water study. AOC method optimization showed that river water bacteria could pass through a 0.2μm membrane filter, and therefore membrane filtration combined with heat treatment was required for sample sterilization. Preparation of the natural river inoculum with an acceptable yield value could only be achieved when grown using the natural water source, since growth was limited on different types of inorganic minimal media and in natural spring water. The resulting flow cytometry AOC method was reliable and reproducible, and results were comparable to the standard plate count AOC method. Size exclusion chromatography showed that both high and low molecular weight organic matter fractions were utilized by the natural AOC inoculum. Flow cytometry was used to measure both AOC levels and total cell counts in a long term study to monitor the water quality of a river which was used as a drinking water source. The method could distinguish between high nucleic acid (HNA) and low nucleic acid (LNA) groups of bacteria, and HNA bacteria were found to respond faster than LNA bacteria to seasonal changes in nutrients and water temperature.
流式细胞术是一种用于快速细胞计数的高效监测工具，可应用于水质及水处理研究。在本研究中，一种采用流式细胞术和天然微生物接种物来测定可同化有机碳（AOC）的方法，经调整后适用于具有高有机物和颗粒含量的复杂地表水，并随后应用于一项长期河水研究中。AOC方法优化表明，河水中的细菌能够通过0.2μm的滤膜，因此样品灭菌需要采用膜过滤结合热处理的方式。只有使用天然水源培养时，才能制备出具有可接受产率值的天然河水接种物，因为在不同类型的无机基本培养基以及天然泉水中生长受到限制。所得的流式细胞术AOC方法可靠且可重复，结果与标准平板计数AOC方法相当。尺寸排阻色谱显示，天然AOC接种物能够利用高分子量和低分子量的有机物组分。在一项长期研究中，流式细胞术用于测量AOC水平和总细胞计数，以监测作为饮用水源的一条河流的水质。该方法能够区分细菌的高核酸（HNA）和低核酸（LNA）群体，并且发现HNA细菌对营养物和水温的季节性变化的响应比LNA细菌更快。
