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摘要用NTG对福氏痢疾杆菌进行诱变处理。在NTG浓度为0.1和1mg/ml，pH6.0（0.2M）磷酸盐缓冲液作用条件下，处理30分钟和60分钟。分别获得1.33～7.1%的诱变率。所获得的营养缺陷型64.7%为氨基酸缺陷型。其次为维生素缺陷型（17.6%）和嘌呤嘧啶缺陷型（14.7%）。只得到少量双重营养缺陷型。亮氨酸和甲硫氨酸的自发回复突变率为1.35×10 -10，半胱氨酸为6.67×10 -9，腺嘌呤为1.95×10 -6。测定的10株不同营养缺陷突变体中4株仍保持引起豚鼠角膜结膜炎的能力，另外6株已失去此种能力。

abstractsStrains of Sh. flexneri were treated with NTG (its concentration being 0.1 and 1 mg/ml) in 0.2 M phosphate buffer (pH 6.0) for 30 min and 60 min to induce mutation. The mutagenic rate was found from 1.33% to 7.1%. Among the auxotrophs obtained, the majority were single amino-acids synthesis defective i.e. 64.7%, whereas 17.6% were vitamin-defective and 14.7% were purine-pyrimidine defective and only in a few strains were multiple defects found in two amino-acids (phenylalanine and tyrosine) and adenine-Vit. Bl. The spontaneous reversion rate of leucine and methionine was found to be lower than 1.33×10 -10, that for cysteine lower than 6.67×10 -9, and that for adenine was 1.95×10 -6. Among 10 strains of different auxotrophic mutants tested, 4 were still found to be capable of causing keratoconjunctivitis in guinea pig, and 6 strains failed to cause keratoconjunctivitis.