Cleary P P
Infect Immun. 1978 Oct;22(1):171-5. doi: 10.1128/iai.22.1.171-175.1978.
Mutagenized cultures of three strains of group A streptococci which were M positive and produced the extracellular serum opacity factor (OF) were screened for mutants which failed to exhibit OF activity on serum agar plates. All cell fractions from three mutants studied in detail, including culture supernatants, protoplast membranes, and cytoplasmic fractions, were completely devoid of activity. Two OF- isolates also lacked OF antigen, whereas the third continued to produce cross-reacting antigen. All three mutants were resistant to phagocytosis and yielded acid-extractable M antigen, indicating that the M protein of each strain was unaltered by the mutations. The separation of the OF+ and M+ phenotypes by mutation establishes that genes which code for the M protein and OF are distinct; therefore, the activities and antigenic determinants of each must be associated with separate, distinct protein molecules.
对三株A群链球菌进行诱变培养，这些菌株M抗原阳性且能产生细胞外血清混浊因子（OF），从中筛选在血清琼脂平板上不表现OF活性的突变体。对详细研究的三个突变体的所有细胞组分，包括培养上清液、原生质体膜和细胞质组分，均完全没有活性。两个OF阴性分离株也缺乏OF抗原，而第三个继续产生交叉反应抗原。所有三个突变体均对吞噬作用有抗性，并产生酸可提取的M抗原，表明每个菌株的M蛋白未因突变而改变。通过突变分离OF阳性和M阳性表型表明，编码M蛋白和OF的基因是不同的；因此，它们各自的活性和抗原决定簇必定与单独、不同的蛋白质分子相关。
