Use of silkworm larvae to study pathogenic bacterial toxins
Use of silkworm larvae to study pathogenic bacterial toxins
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DOI：
10.1093/jb/mvj171
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发表时间：
2006-09-01
影响因子：
2.7
通讯作者：
Sekimizu, Kazuhisa
中科院分区：
文献类型：
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作者：
Hossain, Muktadir S.;Hamamoto, Hiroshi;Sekimizu, Kazuhisa
将金黄色葡萄球菌和铜绿假单胞菌的固定相培养上清液注射到家蚕幼虫的血淋巴中可导致其死亡，而非致病性大肠杆菌的培养上清液则不会导致其死亡。agr突变体（金黄色葡萄球菌的全球毒力调节剂，是产生外毒素所必需的）的培养上清液对家蚕幼虫的毒性要小得多。金黄色葡萄球菌β -毒素基因突变体的培养上清不能杀死幼虫，而α -毒素、γ -毒素或金溶素的缺失突变体的培养上清可以杀死幼虫，这表明β -毒素基因是葡萄球菌上清介导的杀死家蚕幼虫所必需的。葡萄球菌α毒素和β毒素、假单胞菌外毒素A和白喉毒素的50%致死量（LD50）分别为12 μ g/g、9 μ g/g、0.14 μ g/g和1.1 μ g/g。由于纯化后的毒素能杀死家蚕幼虫，因此可以用家蚕幼虫作为研究致病菌毒素在动物体内作用的模型。
Injection of stationary phase culture-supernatants of Staphylococcus aureus and Pseudomonas aeruginosa into the hemolymph of silkworm larvae caused their death, whereas a culture-supernatant of a non-pathogenic strain of Escherichia coli did not. A culture-supernatant of a mutant of agr, a global virulence regulator of S. aureus that is required for exotoxin production, was much less toxic to silkworm larvae. A culture-supernatant of a disruption mutant of the S. aureus beta-toxin gene did not kill larvae, whereas one of a deletion mutant of alpha-toxin, gamma-toxin, or aureolysin killed larvae, indicating that the beta-toxin gene is required for staphylococcal supernatant-mediated killing of silkworm larvae. The 50% lethal doses (LD50) of staphylococcal alphatoxin and beta-toxin, Pseudomonas exotoxin A and diphtheria toxin were 12 mu g/g, 9 mu g/g, 0.14 mu g/g and 1.1 mu g/g, respectively. As the purified toxins killed the larvae, silkworm larvae could be used as a model to study the actions of pathogenic bacterial toxins in animal bodies.