Smirnova G V, Muzyka N G, Glukhovchenko M N, Oktiabr'skiĭ O N
Institute of Ecology and Genetics of Microorganisms, Ural Division, Russian Academy of Sciences, Perm, Russia.
Mikrobiologiia. 1998 Sep-Oct;67(5):594-600.
Exposure of growing Escherichia coli K12 cells to 2.0-11.0 mM H2O2 resulted in an increase in the intracellular level of low-molecular-weight thiols (LMWT), whereas exposure to 25 mM H2O2 resulted in its decrease. An inverse correlation between levels of LMWT and potassium was revealed. The treatment of E. coli delta oxyR cells, which are incapable of the adaptive response to H2O2, with 10 mM H2O2 caused a decrease in the LMWT level. In E. coli oxyR2 cells, which constitutively express oxyR-controlled proteins, the same treatment caused a 20% increase in the LMWT level. In response to treatment with the oxidant, delta oxyR mutants lost two times more potassium than wild-type cells (oxyR+). A time course study of the levels of LMWT and potassium in mutants with an affected katG gene, which encodes the HPI catalase and is under the control of oxyR, showed that oxyR may regulate LMWT and potassium levels indirectly, through the regulation of catalase activity. A relationship between catalase activity and the LMWT level was revealed in hydrogen peroxide-treated E. coli cells.
将生长中的大肠杆菌K12细胞暴露于2.0 - 11.0 mM的过氧化氢中会导致细胞内低分子量硫醇（LMWT）水平升高，而暴露于25 mM过氧化氢中则会导致其水平降低。研究发现LMWT水平与钾含量呈负相关。用10 mM过氧化氢处理无法对过氧化氢产生适应性反应的大肠杆菌delta oxyR细胞，会导致LMWT水平降低。在组成型表达oxyR调控蛋白的大肠杆菌oxyR2细胞中，相同处理会使LMWT水平升高20%。作为对氧化剂处理的反应，delta oxyR突变体比野生型细胞（oxyR+）多损失两倍的钾。对受katG基因影响的突变体中LMWT和钾水平的时间进程研究表明，katG基因编码HPI过氧化氢酶且受oxyR控制，oxyR可能通过调节过氧化氢酶活性间接调节LMWT和钾水平。在过氧化氢处理的大肠杆菌细胞中发现了过氧化氢酶活性与LMWT水平之间的关系。
