Ferrous Iron-Dependent Volatilization of Mercury by the Plasma Membrane of Thiobacillus ferrooxidans
Ferrous Iron-Dependent Volatilization of Mercury by the Plasma Membrane of Thiobacillus ferrooxidans
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氧化亚铁硫杆菌质膜的二价铁依赖性汞挥发
DOI：
10.1128/aem.66.9.3823-3827.2000
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发表时间：
2000
影响因子：
4.4
通讯作者：
T. Sugio
中科院分区：
文献类型：
--
作者：
K. Iwahori;F. Takeuchi;K. Kamimura;T. Sugio
摘要 在分离的 100 株铁氧化菌中，氧化亚铁硫杆菌 SUG 2-2 对汞毒性的抵抗力最强，可以在补充有 6 μM Hg2+ 的 Fe2+ 培养基（pH 2.5）中生长。相比之下，氧化亚铁菌 AP19-3（一种对汞敏感的氧化亚铁菌菌株）在 0.7 μM Hg2+ 下无法生长。当在含有 0.7 μM Hg2+ 的盐溶液（pH 2.5）中孵育 3 小时时，耐药菌株和敏感菌株的静息细胞分别挥发了添加总汞的约 20% 和 1.7%。添加 Fe2+ 后，耐药细胞（而非敏感细胞）的汞挥发量增加至 62%。汞挥发活性的最适pH和温度分别为2.3和30℃。氰化钠、钼酸钠、钨酸钠和硝酸银强烈抑制氧化亚铁菌依赖Fe2+的汞挥发活性。当在含有 0.7 μM Hg2+ 和 1 mM Fe2+ 的盐溶液（pH 3.8）中孵育时，由耐药细胞制备的质膜在孵育 5 天后挥发了添加的汞总量的 48%。然而，该膜不具有以NADPH作为电子供体的汞还原酶活性。用 2 mM 氰化钠预处理的质膜未观察到 Fe2+ 依赖性汞挥发活性。抗性细胞中的锈花苷激活质膜的铁氧化活性，并激活质膜的 Fe2+ 依赖的汞挥发活性。
ABSTRACT Of 100 strains of iron-oxidizing bacteria isolated,Thiobacillus ferrooxidans SUG 2-2 was the most resistant to mercury toxicity and could grow in an Fe2+ medium (pH 2.5) supplemented with 6 μM Hg2+. In contrast, T. ferrooxidans AP19-3, a mercury-sensitive T. ferrooxidans strain, could not grow with 0.7 μM Hg2+. When incubated for 3 h in a salt solution (pH 2.5) with 0.7 μM Hg2+, resting cells of resistant and sensitive strains volatilized approximately 20 and 1.7%, respectively, of the total mercury added. The amount of mercury volatilized by resistant cells, but not by sensitive cells, increased to 62% when Fe2+ was added. The optimum pH and temperature for mercury volatilization activity were 2.3 and 30°C, respectively. Sodium cyanide, sodium molybdate, sodium tungstate, and silver nitrate strongly inhibited the Fe2+-dependent mercury volatilization activity of T. ferrooxidans. When incubated in a salt solution (pH 3.8) with 0.7 μM Hg2+ and 1 mM Fe2+, plasma membranes prepared from resistant cells volatilized 48% of the total mercury added after 5 days of incubation. However, the membrane did not have mercury reductase activity with NADPH as an electron donor. Fe2+-dependent mercury volatilization activity was not observed with plasma membranes pretreated with 2 mM sodium cyanide. Rusticyanin from resistant cells activated iron oxidation activity of the plasma membrane and activated the Fe2+-dependent mercury volatilization activity of the plasma membrane.