钙对固氮菌糖转运的影响。
Effects of Calcium on Sugar Transport in Azotobacter vinelandii.
机构信息
Biology Department, Memphis State University, Memphis, Tennessee 38152.
出版信息
Appl Environ Microbiol. 1993 Jan;59(1):89-92. doi: 10.1128/aem.59.1.89-92.1993.
A fast and environmentally safe procedure was used to study sugar uptake by Azotobacter vinelandii. Transport experiments were performed in a 24-well plate and aerated by rapid oscillatory vibration. Samples were washed by centrifugation and dissolved in biodegradable scintillation cocktail for counting. At cell concentrations up to 6 x 10 cells per ml, the uptake of sucrose was a function of time and was proportional to the cell concentration. This modified uptake assay was used to test the effect of cations on sugar uptake in A. vinelandii. Results showed that Ca at 1 to 2 mM stimulated sucrose uptake by decreasing the apparent K(m) of sucrose transport. Higher Ca concentrations inhibited sucrose uptake in this organism.
采用快速、环保的方法研究了固氮菌对糖的摄取。在 24 孔板中进行了运输实验，并通过快速振荡振动进行通气。通过离心洗涤样品，并溶解在可生物降解的闪烁混合物中进行计数。在细胞浓度高达每毫升 6 x 10 个细胞的情况下，蔗糖的摄取是时间的函数，并与细胞浓度成正比。这种改良的摄取测定法用于测试阳离子对固氮菌中糖摄取的影响。结果表明，1 至 2mM 的 Ca 通过降低蔗糖转运的表观 Km 来刺激蔗糖摄取，而较高的 Ca 浓度则抑制了该生物对蔗糖的摄取。
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