Assay of Escherichia coli enterotoxins by in vivo perfusion in the rat jejunum
Assay of Escherichia coli enterotoxins by in vivo perfusion in the rat jejunum
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大鼠空肠体内灌注法测定大肠杆菌肠毒素
DOI：
10.1128/iai.14.4.1004-1010.1976
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发表时间：
1976
影响因子：
3.1
通讯作者：
R. Engert
中科院分区：
文献类型：
--
作者：
F. Klipstein;C. S. Lee;R. Engert
通过检查不同制备的热不稳定（LT）和热稳定（ST）毒素组分对该系统中水转运的影响，评价了大鼠体外灌流大肠杆菌肠毒素的测定。发现该试验以剂量相关方式对LT和ST的响应同样良好;其灵敏度足以检测低至1 ng/ml浓度的致突变效应。与测定，它被发现，LT是产生在有氧条件下生长的培养物，但不是厌氧的，条件;相反，ST是阐述在静止的有氧和厌氧肉汤培养，但不是在搅拌有氧条件下生长的。这两种毒素都可以用硫酸铵或丙酮沉淀。通过连续超滤将两种毒素形式彼此完全分离。单独的LT（暴露于100 ℃ 30分钟后不耐热）被PM-30膜保留，单独的ST存在于UM-2渗余物中; ST被UM-05膜更有效地保留，活性比UM-2渗余物增加1,000倍。含有来自适当培养条件的LT或ST的洗涤过的超滤截留物均在每ml 100 ng或更低的浓度下诱导水分泌。这些结果表明，在大鼠体内灌注是一个敏感的，可重复的测定LT和ST形式的E。大肠杆菌肠毒素
Assay of Escherichia coli enterotoxins by in vitro perfusion in rats was evaluated by examining the effects of variously prepared fractions of heat-labile (LT) and heat-stable (ST) toxins on water transport in this system. The assay was found to respond equally well, in a dose-related manner, to both LT and ST; it was sufficiently sensitive to detect the toxigenic effect of concentrations as small as 1 ng/ml. With the assay, it was found that LT is produced in cultures grown under aerobic, but not anaerobic, conditions; in contrast, ST is elaborated in stationary aerobic and anaerobic broth cultures but not in those grown under agitated aerobic conditions. Both toxins can be precipitated by either ammonium sulfate or acetone. The two toxin forms were completely separated from each other by sequential ultrafiltration. LT alone (thermolabile after exposure to 100 degrees C for 30 min) was retained by a PM-30 membrane, and ST alone was present in UM-2 retentates; ST was retained more effectively by a UM-05 membrane, with a 1,000-fold increase in activity over that of the UM-2 retentate. Washed ultrafiltration retentates containing either LT or ST derived from the proper culture conditions all induced water secretion at concentrations of 100 ng or less per ml. These results indicate that in vivo perfusion in rats is a sensitive, duplicable assay for both the LT and ST forms of E. coli enterotoxin.