Department of Microbiology, University of Alberta, Edmonton, Alberta, Canada T6G 2E9.
Appl Environ Microbiol. 1986 Mar;51(3):510-4. doi: 10.1128/aem.51.3.510-514.1986.
The majority of Azotobacter chroococcum strains in a collection obtained from Alberta soils were absolutely dependent on Na for growth. Two strains from the American Type Culture Collection also were either Na dependent or were stimulated by Na. Optimal growth required 0.8 mM Na and was limited at 0.2 to 0.35 mM Na. Growth promoted by 0.8 mM Na was inhibited by Rb > K >> NH(4) but was not affected by Li. Growth inhibition by Rb and K was overcome by increasing the Na concentration present in the medium. Excellent growth in media containing limiting Na was obtained when 25 mM Li or 25 mM Mg was added. Li was significantly more effective in replacing Na than was Mg. Na was required for growth on all C sources (glucose, sucrose, melibiose, and mannitol) and N sources (N(2), NH(4), and NO(3)) and was required throughout the pH range of growth. Cells suspended in Na -deficient medium or in distilled water did not appear to lyse or lose viability.
从阿尔伯塔土壤中获得的收集物中的大多数棕色固氮菌菌株的生长完全依赖于 Na。美国典型培养物保藏中心的两个菌株也依赖于 Na 或被 Na 刺激。最佳生长需要 0.8 mM Na，在 0.2 至 0.35 mM Na 时受到限制。0.8 mM Na 促进的生长受到 Rb > K >> NH(4) 的抑制，但不受 Li 影响。通过增加培养基中存在的 Na 浓度可以克服 Rb 和 K 的生长抑制。当添加 25 mM Li 或 25 mM Mg 时，可以在含有有限 Na 的培养基中获得良好的生长。Li 比 Mg 更有效地替代 Na。Na 是所有 C 源（葡萄糖、蔗糖、蜜二糖和甘露醇）和 N 源（N(2)、NH(4)和 NO(3))生长所必需的，并且在生长的整个 pH 范围内都是必需的。悬浮在缺乏 Na 的培养基或蒸馏水中的细胞似乎不会裂解或失去活力。
