Dias F M, Ventullo R M, Rowe J J
University of Dayton, Department of Biology, Ohio 45469.
Biochem Biophys Res Commun. 1990 Jan 15;166(1):424-30. doi: 10.1016/0006-291x(90)91962-r.
Nitrate transport and its regulation by oxygen was studied in denitrifying halophilic Pseudomonas stutzeri, strain Zobell, and a Tn-5 transposon nitrite reductase mutant of this organism. The rate of nitrate transport was found to be 130 nanomoles nitrate min-1 mg protein-1 and 150 nanomoles nitrate min-1 mg protein-1 in the wildtype and the nitrite reductase mutant respectively as compared to 26.4 nanomoles nitrate min-1 mg protein-1 in a non-halophilic Pseudomonas stutzeri. Asparagine was found to be the best energy source for nitrate uptake. The ratio of nitrate import to nitrite export was established by measuring extracellular nitrate and nitrite concentrations using HPLC/UV analysis. There was a 1.3:1 (NO3-/NO2-) exchange. High concentrations of nitrate during growth was found to have a negative effect on nitrite metabolism. Oxygen exerted an inhibitory effect on nitrate uptake which was reversible and more pronounced in cells grown on low concentrations of nitrate compared to cells grown at high concentrations of nitrate.
在反硝化嗜盐施氏假单胞菌Zobell菌株及其该菌株的一个Tn-5转座子亚硝酸还原酶突变体中研究了硝酸盐转运及其受氧的调节。发现野生型和亚硝酸还原酶突变体中硝酸盐转运速率分别为130纳摩尔硝酸盐每分钟每毫克蛋白质和150纳摩尔硝酸盐每分钟每毫克蛋白质，相比之下，非嗜盐施氏假单胞菌中的硝酸盐转运速率为26.4纳摩尔硝酸盐每分钟每毫克蛋白质。发现天冬酰胺是硝酸盐摄取的最佳能量来源。通过使用HPLC/UV分析测量细胞外硝酸盐和亚硝酸盐浓度来确定硝酸盐输入与亚硝酸盐输出的比率。存在1.3:1（NO3-/NO2-）的交换。发现生长期间高浓度的硝酸盐对亚硝酸盐代谢有负面影响。氧对硝酸盐摄取有抑制作用，该作用是可逆的，并且与在高浓度硝酸盐下生长的细胞相比，在低浓度硝酸盐下生长的细胞中这种抑制作用更明显。
