Baker H, Frank O, Tuma D J, Barak A J, Sorrell M F, Hutner S H
Am J Clin Nutr. 1978 Mar;31(3):532-40. doi: 10.1093/ajcn/31.3.532.
The sensitive, specific growth response to choline activity of the thermophilic enteric yeast Torulopsis pintolopessi enables estimation of free and bound choline activity in rat and human fluids and tissues- as little as 10 ng/ml of choline is measurable. Unlike other microbial assays, estimation of unbound (free) choline activity is not influenced by methionine or phospholipids. The method also distinguishes differences in choline activity of fluids and tissues from choline-deficient and choline-replete rats. Free and bound choline activity in blood, red blood cells, plasma, and liver from choline-deficient rats were almost 2-fold lower than from choline-supplemented animals. Free and bound choline activity in whole brain from choline-deficient rats were signifigantly higher (more than 2-fold). The application of the T. pintolopessi method in studying choline status in man and reasons for high choline activity in brain of choline-deficient rats are suggested.
嗜热肠道酵母毕氏酵母对胆碱活性具有敏感、特异的生长反应，这使得能够估计大鼠和人体体液及组织中游离和结合胆碱的活性——低至10 ng/ml的胆碱都可测量。与其他微生物测定法不同，未结合（游离）胆碱活性的估计不受蛋氨酸或磷脂的影响。该方法还能区分胆碱缺乏和胆碱充足大鼠的体液和组织中胆碱活性的差异。胆碱缺乏大鼠的血液、红细胞、血浆和肝脏中游离和结合胆碱活性比补充胆碱的动物低近2倍。胆碱缺乏大鼠全脑中游离和结合胆碱活性显著更高（超过2倍）。文中提出了毕氏酵母方法在研究人体胆碱状态中的应用以及胆碱缺乏大鼠脑中胆碱活性高的原因。
