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首页> 外文期刊>Infection and immunity >Assay of Escherichia coli enterotoxins by in vivo perfusion in the rat jejunum.
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Assay of Escherichia coli enterotoxins by in vivo perfusion in the rat jejunum.

机译：通过在大鼠空肠中进行体内灌注来测定大肠杆菌肠毒素。

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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.
机译：通过检查大鼠体内不同程度的热不稳定性（LT）和热稳定（ST）毒素对系统中水传输的影响，评估了大鼠体外灌注大肠埃希氏菌肠毒素的含量。发现该测定以剂量相关的方式对LT和ST均反应良好。它足以检测浓度低至1 ng / ml的毒物作用。通过该测定，发现LT是在有氧而非厌氧条件下生长的培养物中产生的。相比之下，ST在固定的需氧和厌氧培养液中得到了详细说明，而在搅拌需氧条件下培养的则没有。两种毒素均可被硫酸铵或丙酮沉淀。通过顺序超滤将两种毒素形式完全分离。单独的LT（暴露于100摄氏度30分钟后具有热稳定性）被PM-30膜保留，而单独的ST存在于UM-2截留物中。 ST被UM-05膜更有效地保留，其活性比UM-2截留物高1000倍。含有源自适当培养条件的LT或ST的洗涤过的超滤渗余物均以每毫升100 ng或更少的浓度诱导水分泌。这些结果表明，大鼠体内灌注是针对大肠杆菌肠毒素的LT和ST形式的灵敏，可重复的测定。

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