Jacks T M, Wu B J, Braemer A C, Bidlack D E
Infect Immun. 1973 Feb;7(2):178-89. doi: 10.1128/iai.7.2.178-189.1973.
The enterotoxic component in sterile syncase broth filtrates of Escherichia coli strains 340 (O9:K.:NM) and P307 (O8:K87,88a,b:H19) was studied. The enterotoxic activity in both strains was retained by an ultrafiltration membrane with a molecular weight retention of 100,000 (XM-100A) and eluted from a Sephadex G-200 column in the void volume. The enterotoxic activity in strain 340 was resistant to heating at 75 C for 30 min, but the activity in strain P307 was destroyed by heating at 60 C for 30 min. The P307 Sephadex G-200 column eluate possessing the enterotoxic activity, when desalted, contained 45.8% carbohydrate and 9.3% protein, and had an ED(50) of 2.2 mg/rabbit ileal loop. Immunodiffusion studies showed that this material contained both endotoxin and acid-polysaccharide capsular material. The enterotoxic activity was acidlabile and was destroyed by Pronase, but was resistant to trypsin and eluted as a single peak in the void volume of a 4% agarose column. The enterotoxic component could not be separated from the endotoxin; in fact, the data indicated that the two components are closely associated and that the enterotoxic activity resides in material of a protein nature.
对大肠杆菌340株（O9:K.:NM）和P307株（O8:K87,88a,b:H19）无菌合酶肉汤滤液中的肠毒素成分进行了研究。两株菌的肠毒素活性均能被截留分子量为100,000的超滤膜（XM - 100A）保留，并从Sephadex G - 200柱的空体积中洗脱出来。340株菌的肠毒素活性在75℃加热30分钟后仍保持稳定，但P307株菌的活性在60℃加热30分钟后被破坏。具有肠毒素活性的P307 Sephadex G - 200柱洗脱液脱盐后，含有45.8%的碳水化合物和9.3%的蛋白质，对兔回肠袢的半数有效剂量（ED50）为2.2mg。免疫扩散研究表明，该物质同时含有内毒素和酸性多糖荚膜物质。肠毒素活性对酸不稳定，能被链霉蛋白酶破坏，但对胰蛋白酶有抗性，并在4%琼脂糖柱的空体积中以单一峰形洗脱。肠毒素成分无法与内毒素分离；事实上，数据表明这两种成分紧密相关，且肠毒素活性存在于蛋白质性质的物质中。
