Tannich E, Bruchhaus I, Walter R D, Horstmann R D
Bernhard Nocht Institute for Tropical Medicine, Hamburg, F.R.G.
Mol Biochem Parasitol. 1991 Nov;49(1):61-71. doi: 10.1016/0166-6851(91)90130-x.
Superoxide dismutase (SOD) activity was determined in the cell lysate of the axenically cultured Entamoeba histolytica isolate HM-1:IMSS. Under anaerobic culture conditions, 18.7 (+/- 4.9) units SOD activity (mg protein)-1 were found. By inhibition studies the activity was attributed to an iron-containing type of SOD (FeSOD). Using degenerate oligonucleotide primers derived from regions highly conserved in prokaryotic FeSOD sequences, a genomic DNA fragment was amplified by the polymerase chain reaction. The fragment was used to isolate FeSOD specific cDNA clones from a pathogenic and a nonpathogenic E. histolytica isolate. A comparison of the 2 sequences revealed 5% nucleotide differences resulting in a single amino acid exchange. The primary structure showed the characteristics of an iron-containing type of SOD with a homology of approximately 55% with other FeSOD sequences. The enzyme was found to be encoded by single copy genes in both the pathogenic and the nonpathogenic E. histolytica, but restriction fragment lengths differed between the 2 groups. In 5 isolates studied, no correlation was found between pathogenic behavior of the amebae and the expression of FeSOD-related mRNA.
在无菌培养的溶组织内阿米巴分离株HM-1:IMSS的细胞裂解物中测定了超氧化物歧化酶（SOD）活性。在厌氧培养条件下，发现SOD活性为18.7（±4.9）单位（毫克蛋白）-1。通过抑制研究，该活性归因于含铁类型的SOD（FeSOD）。使用源自原核FeSOD序列中高度保守区域的简并寡核苷酸引物，通过聚合酶链反应扩增基因组DNA片段。该片段用于从致病性和非致病性溶组织内阿米巴分离株中分离FeSOD特异性cDNA克隆。对这两个序列的比较揭示了5%的核苷酸差异，导致单个氨基酸交换。一级结构显示出含铁类型SOD的特征，与其他FeSOD序列的同源性约为55%。发现该酶在致病性和非致病性溶组织内阿米巴中均由单拷贝基因编码，但两组之间的限制性片段长度不同。在所研究的5个分离株中，未发现阿米巴的致病行为与FeSOD相关mRNA的表达之间存在相关性。
