Park Sunhwa, Ely Roger L
Department of Biological and Ecological Engineering, Oregon State University, Corvallis, OR 97331, USA.
Arch Microbiol. 2008 Jun;189(6):541-8. doi: 10.1007/s00203-007-0341-7. Epub 2007 Dec 21.
Nitrosomonas europaea, a Gram-negative obligate chemolithoautotroph, participates in global nitrogen cycling by carrying out nitrification and derives energy for growth through oxidation of ammonia. In this work, the physiological, proteomic, and transcriptional responses of N. europaea to zinc stress were studied. The nitrite production rate and ammonia-dependent oxygen uptake rate of the cells exposed to 3.4 microM ZnCl2 decreased about 61 and 69% within 30 min, respectively. Two proteins were notably up regulated in zinc treatment and the mRNA levels of their encoding genes started to increase by 1 h after the addition of zinc. A total of 27 genes were up regulated and 30 genes were down regulated. Up-regulated genes included mercury resistance genes (merTPCAD), inorganic ion transport genes, oxidative stress genes, toxin-antitoxin genes, and two-component signal transduction systems genes. merTPCAD was the highest up-regulated operon (46-fold). Down-regulated genes included the RubisCO operon (cbbO), biosynthesis (mrsA), and amino acid transporter.
欧洲亚硝化单胞菌是一种革兰氏阴性专性化能自养菌，通过进行硝化作用参与全球氮循环，并通过氨氧化获取生长所需能量。在本研究中，对欧洲亚硝化单胞菌对锌胁迫的生理、蛋白质组和转录反应进行了研究。暴露于3.4微摩尔/升氯化锌的细胞，其亚硝酸盐产生率和氨依赖型氧摄取率在30分钟内分别下降了约61%和69%。在锌处理中，有两种蛋白质显著上调，其编码基因的mRNA水平在添加锌后1小时开始增加。共有27个基因上调，30个基因下调。上调基因包括汞抗性基因（merTPCAD）、无机离子转运基因、氧化应激基因、毒素-抗毒素基因和双组分信号转导系统基因。merTPCAD是上调幅度最大的操纵子（46倍）。下调基因包括核酮糖-1,5-二磷酸羧化酶/加氧酶操纵子（cbbO）、生物合成基因（mrsA）和氨基酸转运蛋白。
