Institute of Integrative Biology, University of Liverpool, Liverpool, UK.
Acta Physiol (Oxf). 2011 Jul;202(3):583-92. doi: 10.1111/j.1748-1716.2010.02243.x. Epub 2011 Mar 1.
The ability of high carbon dioxide tensions or low pH to reduce blood oxygen binding even at high oxygen tensions, first observed by August Krogh and Isabella Leitch in 1919 and now known as the Root effect, was studied in red blood cells and haemoglobin solutions of several fish species.
Red blood cells in physiological saline were acidified at atmospheric oxygen tension by increasing carbon dioxide tensions and the percentage decrease in oxygen content was used to quantify the Root effect. Haemoglobin was incubated in air-equilibrated citrate buffers between pH 5 and 7 and the percentage decrease in oxygen saturation relative to pH 8 determined by spectral deconvolution.
The maximal magnitude of the Root effect in citrate-buffered haemoglobin solutions closely matched the value in blood or red blood cells of 11 vertebrates over a Root effect range between 3 and 80%. Contrary to previous reports, there was no evidence for a significant Root effect in red blood cells or haemoglobin solutions of the wels catfish, but a significant Root effect under both conditions in the Siberian sturgeon.
Under the conditions employed in this study, the maximal Root effect of citrate-buffered haemoglobin solutions closely resembles the maximal Root effect in red blood cells. This strengthens previous studies on the evolution of the Root effect and its role in oxygen concentration at the retina and swimbladder of a large number of fishes that were based on Root effect measurements in haemoglobin solutions.
高二氧化碳张力或低 pH 值降低血液氧结合能力的能力，即使在高氧张力下，也首次被 August Krogh 和 Isabella Leitch 于 1919 年观察到，现在被称为 Root 效应，在几种鱼类的红细胞和血红蛋白溶液中进行了研究。
在大气氧张力下，通过增加二氧化碳张力使生理盐水中的红细胞酸化，并使用氧含量的百分比降低来量化 Root 效应。血红蛋白在 pH 值为 5 至 7 的空气平衡柠檬酸盐缓冲液中孵育，并通过光谱解卷积确定相对于 pH 值 8 的氧饱和度的百分比降低。
在 pH 值为 5 至 7 的空气平衡柠檬酸盐缓冲液中孵育血红蛋白，Root 效应的最大幅度与 11 种脊椎动物的血液或红细胞中的值非常匹配，Root 效应范围在 3 至 80%之间。与之前的报告相反，在泥鳅的红细胞或血红蛋白溶液中没有明显的 Root 效应，但在两种条件下，西伯利亚鲟鱼都有明显的 Root 效应。
在本研究中采用的条件下，柠檬酸盐缓冲血红蛋白溶液的最大 Root 效应与红细胞中的最大 Root 效应非常相似。这加强了之前关于 Root 效应的进化及其在大量鱼类视网膜和鳔氧浓度中的作用的研究，这些研究是基于血红蛋白溶液中的 Root 效应测量得出的。
