Ohman D E, Sadoff J C, Iglewski B H
Infect Immun. 1980 Jun;28(3):899-908. doi: 10.1128/iai.28.3.899-908.1980.
An immunological assay utilizing double-diffusion principles was developed for identification of Pseudomonas aeruginosa mutants deficient in toxin A. Mutations were chemically induced, and mutants were isolated from P. aeruginosa strain PA103. Quantitative assays, both enzymatic and immunological, indicated that five mutants produced toxin A in vitro at levels of 0.3% or less of parental strain levels. Characterization indicated that the mutants fell into four classes and suggested that multiple genes are involved in the regulation of toxin A yields. Classes 1 to 3 produced less than 1% of parental levels of extracellular toxin A. Class 1 mutants are apparently specific for toxin A. Class 2 mutants are pleotropic and produced toxin A, protease, and other extracellular proteins at reduced yields. Class 3 mutants are pleotropic and in addition have relatively high levels of cell-bound toxin A. Class 4 mutants produce toxin A at levels greater than 1% of parental yields. Of 16 toxin A-deficient mutants examined, only 1 was a class 1 mutant. This mutant (PA103-29) was shown to be identical to the parental strain in all respects tested except for its marked deficiency in toxin A. The suitability of this class 1 mutant for use in virulence studies is discussed.
开发了一种利用双扩散原理的免疫测定法,用于鉴定毒素A缺陷型铜绿假单胞菌突变体。通过化学诱导产生突变,并从铜绿假单胞菌PA103菌株中分离出突变体。酶学和免疫学定量测定表明,五个突变体在体外产生毒素A的水平为亲本菌株水平的0.3%或更低。特性分析表明,这些突变体分为四类,提示多个基因参与毒素A产量的调控。第1至3类产生的细胞外毒素A低于亲本水平的1%。第1类突变体显然对毒素A具有特异性。第2类突变体具有多效性,产生毒素A、蛋白酶和其他细胞外蛋白的产量降低。第3类突变体具有多效性,此外细胞结合毒素A水平相对较高。第4类突变体产生毒素A的水平高于亲本产量的1%。在检测的16个毒素A缺陷型突变体中,只有1个是第1类突变体。除了毒素A明显缺陷外,该突变体(PA103-29)在所有测试方面均与亲本菌株相同。讨论了该第1类突变体在毒力研究中的适用性。