Brazil G M, Clayton C L, Sekizaki T, Timmis K N
Département de Biochimie Médicale, Centre Médical Universitaire, Genève, Switzerland.
Experientia. 1988 Oct 15;44(10):848-53. doi: 10.1007/BF01941182.
DNA probes to identify the genes encoding toxins in enteric bacteria have been developed. Use of these probes reduces the number of animals required for toxicity testing, as suspect bacteria can be directly tested for the presence of toxin. We have augmented the gene probes available by developing probes against the Escherichia coli enterotoxin LTII and shiga toxin from Shigella dysenteriae 1. The LTII gene from E. coli 357900 was identified and characterised and a suitable internal probe was obtained. The LTII gene was found not to be common among enterobacteriae from various geographical locations. Isolates predominately of animal origin from Nigeria and Thailand hybridized with the probe. The shiga toxin gene was isolated from S. dysenteriae 1 by a combination of in vivo and in vitro methods. An internal probe was identified and used against different serogroups of Shigella and E. coli isolates. The probe was found to hybridize with S. dysenteriae 1 isolates and also some S. flexneri and S. sonnei strains. Representatives were tested for toxin production and found to produce toxin at low levels.
已开发出用于鉴定肠道细菌中编码毒素基因的DNA探针。使用这些探针可减少毒性测试所需的动物数量，因为可疑细菌可直接检测其毒素的存在。我们通过开发针对大肠杆菌肠毒素LTII和痢疾志贺氏菌1型志贺毒素的探针，增加了可用的基因探针。鉴定并表征了来自大肠杆菌357900的LTII基因，并获得了合适的内部探针。发现LTII基因在来自不同地理位置的肠杆菌中并不常见。来自尼日利亚和泰国的主要源自动物的分离株与该探针杂交。通过体内和体外方法相结合，从痢疾志贺氏菌1型中分离出志贺毒素基因。鉴定出一种内部探针，并将其用于针对不同血清群的志贺氏菌和大肠杆菌分离株。发现该探针与痢疾志贺氏菌1型分离株以及一些弗氏志贺氏菌和宋内氏志贺氏菌菌株杂交。对代表性菌株进行毒素产生测试，发现它们产生的毒素水平较低。
