Eisenstadt E, Fisher S, Der C L, Silver S
J Bacteriol. 1973 Mar;113(3):1363-72. doi: 10.1128/jb.113.3.1363-1372.1973.
Manganese is accumulated in Bacillus subtilis by a highly specific active transport system. This trace element "pump" is insensitive to added magnesium or calcium and preferentially accumulates manganese in the presence of cobalt, iron, and copper. Manganese uptake in B. subtilis is inhibited by cyanide, azide, pentachlorophenol, and m-chlorophenyl carbonylcyanide hydrazone. The uptake of manganese follows Michaelis-Menten kinetics, and the net accumulation of manganese is regulated by increasing the V(max) after exposure to manganese-starvation conditions and by decreasing the V(max) for manganese uptake during growth in excess manganese. The K(m) remains constant during these regulatory changes in V(max). Manganese accumulated during growth is exchangeable for exogenous manganese and can be released from the cells by toluene (which causes leakage but not lysis) or by lysis with lysozyme. Two stages can be distinguished with regard to intracellular manganese during the process of growth and sporulation. During logarithmic growth, B. subtilis maintains a relatively constant internal manganese content, which is a function of the external manganese concentration following approximately a Langmuir adsorption isotherm. At the end of log phase, net accumulation of manganese slows. A second phase of net manganese accumulation begins at about the same time during sporulation as the accumulation of calcium begins. The manganese accumulated during growth and early sporulation is exchangeable and therefore relatively "free"; intracellular manganese is converted later during sporulation into a bound form that cannot be released by toluene or lysozyme.
锰通过一种高度特异性的主动运输系统在枯草芽孢杆菌中积累。这种微量元素“泵”对添加的镁或钙不敏感，并且在钴、铁和铜存在的情况下优先积累锰。枯草芽孢杆菌对锰的摄取受到氰化物、叠氮化物、五氯苯酚和间氯苯基羰基氰化物腙的抑制。锰的摄取遵循米氏动力学，并且在暴露于锰饥饿条件后通过增加V(max)以及在过量锰中生长期间通过降低锰摄取的V(max)来调节锰的净积累。在这些V(max)的调节变化过程中，K(m)保持恒定。生长期间积累的锰可与外源锰交换，并且可以通过甲苯（导致渗漏但不裂解）或用溶菌酶裂解从细胞中释放出来。在生长和孢子形成过程中，关于细胞内锰可以区分两个阶段。在对数生长期间，枯草芽孢杆菌维持相对恒定的内部锰含量，这是外部锰浓度的函数，大致遵循朗缪尔吸附等温线。在对数期结束时，锰的净积累减缓。净锰积累的第二阶段在孢子形成期间与钙积累开始的时间大致相同开始。在生长和早期孢子形成期间积累的锰是可交换的，因此相对“游离”；在孢子形成后期，细胞内锰转化为一种不能被甲苯或溶菌酶释放的结合形式。
