REPLACEMENT OF POTASSIUM-IONS BY AMMONIUM-IONS IN DIFFERENT MICROORGANISMS GROWN IN POTASSIUM-LIMITED CHEMOSTAT CULTURE
REPLACEMENT OF POTASSIUM-IONS BY AMMONIUM-IONS IN DIFFERENT MICROORGANISMS GROWN IN POTASSIUM-LIMITED CHEMOSTAT CULTURE
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DOI：
10.1007/bf00447012
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发表时间：
1989-06-01
影响因子：
2.8
通讯作者：
NEIJSSEL, OM
中科院分区：
文献类型：
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作者：
BUURMAN, ET;PENNOCK, J;NEIJSSEL, OM
无论是肺炎克雷伯氏菌或嗜热脂肪芽孢杆菌的钾限制培养物中现存的生物量浓度（当在葡萄糖/铵盐培养基中以固定的温度和稀释率生长时）在培养基pH值从7.0逐步升高至8.5时逐渐增加。由于生物体的大分子组成没有显着变化，这种生物量的增加不能归因于储存型聚合物的积累，但似乎反映了pH依赖性降低细胞的最低K+的需求。值得注意的是，对于不存在铵盐并且在唯一氮源中添加谷氨酸盐或硝酸盐的培养物，pH值的这种影响并不明显;然而，当向谷氨酸盐中添加不同浓度的NH 4Cl时，这种影响再次显现。含培养基。这表明K+被NH+4功能性取代，这一命题与钾离子的离子半径（1.33埃）的密切相似性一致。和铵离子（1.43埃）。在pH8.0，用含有谷氨酸盐（30 mM）和NH 4Cl（100 mM）的培养基，培养B。嗜热脂肪菌在不添加钾的情况下将以0.7h-1的最大速率生长。在这些条件下，细胞含有最大0.1%（w.w）的钾（来源于培养基成分中该元素的污染量），该值应与在最初含有0.5 mM K+的钾限制中生长的细胞的1.4%（w/w）的值进行比较。用K.然而，人们可能无法得出结论，NH+4可以完全取代K+在这些细菌的生长，它确实可以这样做非常广泛。
The biomass concentration extant in potassium-limited cultures of either Klebsiella pneumoniae or Bacillus stearothermophilus (when growing at a fixed temperature and dilution rate in a glucose/ammonium salts medium) increased progressively at the medium pH value was raised step-wise from 7.0 to 8.5. Because the macromolecular composition of the organisms did not vary significantly, this increase in biomass could not be attributed to an accumulation of storage-type polymers but appeared to reflect a pH-dependent decrease in the cells'' minimum K+ requirement. Significantly, this effect of pH was not evident with cultures in which no ammonium salts were present and in which either glutamate or nitrate was added at the sole nitrogen source; however, it was again manifest when various concentration of NH4Cl were added to the glutamate-containing medium. This suggested a functional replacement of K+ by NH+4, a proposition consistent with the close similarity of the ionic radii of the potassium ion (1.33 .ANG.) and the ammonium ion (1.43 .ANG.). At pH 8.0, and with a medium containing both glutamate (30 mM) and NH4Cl (100 mM), cultures of B. stearothermophilus would grow without added potassium at a maximum rate of 0.7 h-1. Under these conditions the cells contained maximally 0.1% (w.w) potassium (derived from contaminating amounts of this element in the medium constituents), a value which should be compared with one of 1.4% (w/w) for cells growing in a potassium-limited containing initially 0.5 mM K+. Qualitatively similar findings were made with cultures of K. pneunoniae; whereas one may not conclude that NH+4 can totally replace K+ in the growth of these bacteria, it can cerarly do so very extensively.