Department of Biophysics, Faculty of Biology, Yerevan State University, 1 A. Manoukian Str., 0025, Yerevan, Armenia.
Cell Biochem Biophys. 2013;67(3):1301-6. doi: 10.1007/s12013-013-9662-0.
Enterococcus hirae grow well under anaerobic conditions by fermenting glucose, accompanied with the decrease of oxidation-reduction potential (Eh) from positive values to negative ones. It was shown that heavy metals-copper and iron ions-affect E. hirae growth and alter Eh and proton-potassium ions fluxes through the cell membrane. The aim of this study was to establish the effects of manganese (II) ions on bacterial growth within the concentration range of 0.01-1 mM and compare with nickel (II) ions' effect. The presence of Mn(2+) during E. hirae ATCC9790 growth had significant effects: The lag phase duration decreased while the specific growth rate was increased; decrease in E h was shifted. In contrast, no visible changes in bacterial growth and Eh were observed in the case of Ni(2+). The effects of these ions on proton-potassium ions fluxes through the cell membrane were estimated in the presence and absence of N,N'-dicyclohexylcarbodiimide (DCCD), inhibitor of the FoF1 ATPase. Stronger effect of Mn(2+) on H(+)-K(+) exchange was detected in the presence of DCCD that can be explained by a possible complex formation between these substances and its direct influence on membrane transport proteins.
海氏肠球菌在厌氧条件下通过发酵葡萄糖生长良好，伴随着氧化还原电位（Eh）从正值降低到负值。研究表明，重金属-铜和铁离子-影响海氏肠球菌的生长，并改变 Eh 和质子-钾离子通过细胞膜的通量。本研究的目的是在 0.01-1 mM 的浓度范围内确定锰（II）离子对细菌生长的影响，并与镍（II）离子的影响进行比较。Mn(2+) 的存在对 E. hirae ATCC9790 的生长有显著影响：延迟期持续时间缩短，比生长速率增加；Eh 降低。相比之下，Ni(2+) 的存在对细菌生长和 Eh 没有明显影响。在存在和不存在 N，N'-二环己基碳二亚胺（DCCD）的情况下，估计了这些离子对质子-钾离子通过细胞膜通量的影响，DCCD 是 FoF1 ATP 酶的抑制剂。在 DCCD 的存在下，检测到 Mn(2+) 对 H(+)-K(+)交换的更强影响，这可以用这些物质之间可能形成复合物及其对膜转运蛋白的直接影响来解释。
