INTERMEDIARY METABOLISM OF LEISHMANIA

核磁共振波谱研究表明 原生动物大利什曼原虫的前鞭毛体与[1-]孵育 13C]在有空气或氧气释放的情况下，作为唯一碳源的葡萄糖 醋酸盐、丙酮酸、琥珀酸和少量甘油 缓冲盐溶液。在完全厌氧条件下，葡萄糖 消费实际上停止了(巴斯德效应的逆转)，除非二氧化碳 目前，琥珀酸酯是甘油生产的主要产品 增加，丙氨酸和D-乳酸也会产生。这是第一次 已知能产生乳酸的D-异构体的寄生虫。比较研究 显示所有四种被测试的利什曼原虫只产生D-乳酸 路易氏锥虫的血流形态同时产生D-乳酸和L-乳酸，而T. 冈比亚布鲁斯只产生L异构体。这些观察结果提出了许多 关于D-乳酸形成的意义的几个问题 锥虫，以及控制锥虫的调控机制 在好氧和厌氧条件下形成的每种产物的量。我们 打算测量某些关键中间代谢物的水平，如 如三磷酸腺苷、葡萄糖-6-磷酸、磷酸烯醇式丙酮酸和果糖-2，6 双磷酸盐，作为氧浓度的函数。了解以下内容 形成的各种产品的水平的变化应该提供洞察力 进入一些控制中间代谢的调节机制 在这些牢房里。3LP-核磁共振谱显示了长链聚磷酸的存在 前鞭毛体，我们已经通过直接酶试验证实了这一点。 多聚磷酸葡萄糖激活剂。电子探针X射线显微分析表明 存在致密的富含磷和镁的液泡。当 细胞在没有碳源和没有碳源的情况下孵化。 磷酸盐、细胞内正磷酸盐和焦磷酸盐水平 增加。这一增长是否有一部分是由于利用 聚磷酸盐仍有待测定。研究将使用以下方法进行 酶分析、电子探针X-射线微量分析和31P-核磁共振 光谱学，以获得关于 多聚磷酸盐的代谢和代谢过程中的变化 有氧向无氧过渡。

Nuclear Magnetic Resonance (NMR) spectroscopy studies show that promastigotes of the protozoan parasite Leishmania major incubated with [1- 13C] glucose as sole carbon source in the presence of air or oxygen release acetate, pyruvate, succinate, and small amounts of glycerol into the buffered salt solution. Under fully anaerobic conditions, glucose consumption practically ceases ("reverse" Pasteur effect) unless CO2 is present, in which case succinate is the major product, glycerol production increases, and alanine and D-lactate are also produced. This is the first parasite known to produce the D- isomer of lactate. Comparative studies show that all four species of Leishmania tested make only D-lactate ' Trypanosome lewisi bloodstream forms make both D- and L- lactate, and T. brucei gambiense makes only the L- isomer. These observations raise many questions concerning the significance of D-lactate formation in the trypanosomatids, and the regulatory mechanisms involved in controlling the amount of each product formed under aerobic versus anaerobic conditions. We intend to measure the levels of certain key intermediate metabolites such as ATP, glucose-6-phosphate, phosphoenolpyruvate, and fructose-2,6 bisphosphate, as a function of oxygen concentration. Knowledge of the changes in levels of the various products formed should provide insight into some of the regulatory mechanisms controlling intermediary metabolism in these cells. 3lP-NMR shows the presence of long chain polyphosphate in promastigotes, and we have confirmed this by a direct enzymatic assay using polyphosphate glucokinase. Electron probe X-ray microanalysis shows the presence of dense vacuoles rich in phosphorous and magnesium. When the cells are incubated in the absence of a carbon source and the absence of phosphate, the intracellular orthophosphate and pyrophosphate levels increase. Whether some of this increase resulted from utilization of the polyphosphate remains to be determined. Studies will be performed using enzymatic assays, electron probe X-ray microanalysis, and 31p-NMR spectroscopy to obtain information on the interrelation between polyphosphate metabolism and the metabolic changes that occur during the aerobic to anaerobic transition.