Bracha R, Diamond L S, Ackers J P, Burchard G D, Mirelman D
Department of Biophysics, Weizmann Institute of Science, Rehovot, Israel.
J Clin Microbiol. 1990 Apr;28(4):680-4. doi: 10.1128/jcm.28.4.680-684.1990.
Most individuals infected with Entamoeba histolytica are reported to be clinically asymptomatic. On the basis of the electrophoretic migration of hexokinase and phosphoglucomutase isoenzymes, two groups of E. histolytica isolates have been classified. Those derived from symptomatic cases were found to have fast-migrating hexokinase bands and were labeled pathogenic. The others, isolated from cyst passers, had (in most cases) slow-migrating bands and were called nonpathogenic. Differences between these two groups of E. histolytica were found recently at the DNA level. Two sets of different DNA probes derived from tandemly repeated sequences present in extrachromosomal circular DNA elements in each group of E. histolytica were characterized. Using these probes with procedures for direct hybridization of trophozoites on nylon membranes, we could correctly correlate hexokinase electromobility with the DNA hybridization signal of 81 different isolates of E. histolytica. The advantages of using DNA probes lie in their sensitivity (fewer than 200 trophozoites can be detected) and specificity. The probes hybridized only with amebae from the E. histolytica species and not with other enteric protozoa and can be useful as a diagnostic tool.
据报道，大多数感染溶组织内阿米巴的个体临床上无症状。根据己糖激酶和磷酸葡萄糖变位酶同工酶的电泳迁移情况，溶组织内阿米巴分离株被分为两组。从有症状病例中分离出的菌株己糖激酶条带迁移速度快，被标记为致病型。其他从排包囊者中分离出的菌株（大多数情况下）条带迁移速度慢，被称为非致病型。最近在DNA水平上发现了这两组溶组织内阿米巴之间的差异。对每组溶组织内阿米巴染色体外环状DNA元件中存在的串联重复序列衍生的两组不同DNA探针进行了表征。使用这些探针以及滋养体在尼龙膜上直接杂交的程序，我们能够正确地将己糖激酶的电泳迁移率与81株不同溶组织内阿米巴分离株的DNA杂交信号相关联。使用DNA探针的优点在于其敏感性（可检测到少于200个滋养体）和特异性。这些探针仅与溶组织内阿米巴种的阿米巴杂交，不与其他肠道原生动物杂交，可用作诊断工具。
