Kakinuma Y
J Bacteriol. 1987 Sep;169(9):4403-5. doi: 10.1128/jb.169.9.4403-4405.1987.
The growth of Streptococcus faecalis at high pH was significantly stimulated by carbonate. In the absence of added carbonate the cells were unable to grow at a pH above 9.5, but in media containing 50 mM HCO3- they grew even at pH 10.5. Both rate and yield of growth at pH 9.5 were significantly stimulated by as little as 5 mM carbonate. The cytoplasmic pH in growing cells was maintained at about 7.8 to 8.2, whereas the medium pH ranged from 8.4 to 9.5. Nigericin and gramicidin D, ionophores which conduct protons, blocked growth at pH 9.5 but not at pH 7.5. These results indicate that lowering of the cytoplasmic pH is essential for the growth of this organism at high pH.
粪肠球菌在高pH值下的生长受到碳酸盐的显著刺激。在不添加碳酸盐的情况下，细胞无法在pH值高于9.5时生长，但在含有50 mM HCO₃⁻的培养基中，它们甚至能在pH值为10.5时生长。低至5 mM的碳酸盐就能显著刺激pH值为9.5时的生长速率和产量。生长细胞的细胞质pH值维持在约7.8至8.2，而培养基pH值范围为8.4至9.5。尼日利亚菌素和短杆菌肽D这两种传导质子的离子载体，会阻断pH值为9.5时的生长，但不会阻断pH值为7.5时的生长。这些结果表明，降低细胞质pH值对于该生物体在高pH值下的生长至关重要。
