Haider K, Albert M J, Hossain A, Nahar S
Laboratory Sciences Division, International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh.
J Med Microbiol. 1991 Dec;35(6):330-7. doi: 10.1099/00222615-35-6-330.
Entero-invasive Escherichia coli (EIEC) and shigellae were tested for contact-haemolysin (CH) with red blood cells (RBCs) of guinea-pig, rabbit, rat, mouse, monkey, man, sheep and chicken; all bacteria showed the best lysis with guinea-pig RBCs. The best culture medium for CH activity of shigellae was tryptic soy broth, and for EIEC it was casamino acid-yeast extract broth with 1 mM CaCl2. CH production by all species was best at the slightly alkaline pH which is optimal for growth; it was also dependent on the presence of a large (140-Mda) plasmid. Pre-treatment of bacteria with homologous antisera inhibited CH activity. Various treatments of bacterial cells and RBCs suggested that CH may be a protein molecule, and that a chitotriose-like moiety may serve as CH receptor. RBCs that were incubated with bacteria at 4 degrees C, or with heat-killed bacteria at 37 degrees C, were not lysed; also, isolated cell-surface components (lipopolysaccharide and outer-membrane protein) did not lyse RBCs. This suggests that metabolically active cells are required for CH activity. Production of CH by both EIEC and shigellae is consistent with a common mechanism for the virulence of these organisms.
对侵袭性大肠杆菌（EIEC）和志贺氏菌进行了检测，观察它们对豚鼠、兔、大鼠、小鼠、猴、人、绵羊和鸡的红细胞（RBC）的接触溶血素（CH）活性；所有细菌对豚鼠红细胞的裂解效果最佳。志贺氏菌CH活性的最佳培养基是胰蛋白胨大豆肉汤，而EIEC的最佳培养基是含有1 mM氯化钙的酪蛋白氨基酸 - 酵母提取物肉汤。所有菌株产生CH的最佳条件是在略碱性pH下，这也是其生长的最佳pH；它还依赖于一个大的（140-Mda）质粒的存在。用同源抗血清预处理细菌可抑制CH活性。对细菌细胞和红细胞的各种处理表明，CH可能是一种蛋白质分子，并且一种几丁三糖样部分可能作为CH受体。在4℃下与细菌孵育的红细胞，或在37℃下与热灭活细菌孵育的红细胞均未被裂解；此外，分离的细胞表面成分（脂多糖和外膜蛋白）也不能裂解红细胞。这表明CH活性需要代谢活跃的细胞。EIEC和志贺氏菌产生CH与这些生物体毒力的共同机制是一致的。
