Huang T T, Malke H, Ferretti J J
Department of Microbiology and Immunology, University of Oklahoma Health Science Center, Oklahoma City 73190.
Infect Immun. 1989 Feb;57(2):502-6. doi: 10.1128/iai.57.2.502-506.1989.
A molecular epidemiological study was conducted to determine the distribution of the streptokinase gene in group A streptococcal strains of different M types and in other streptococcal species. Plasmid pNC1, containing only the internal coding sequence of the streptokinase gene from group C streptococcal strain H46A, was used as a DNA probe in colony and Southern hybridization experiments. Only the pathogenic group A, C, and G streptococci contained a streptokinase gene; 12 other Lancefield group strains did not. A total of 134 group A strains, including 61 M types and 6 T types, were tested. Although only 62% (83 of 134) of the strains tested showed positive streptokinase activity by the casein-plasminogen overlay assay, all strains contained the streptokinase gene as evidenced by strong hybridization with the pNC1 probe. Southern blot DNA hybridizations were carried out with 101 strains of group A streptococci. The restriction enzymes HindIII and HaeIII were used to digest the genomic DNA. Six hybridization patterns were observed after HindIII digestion. Double hybridization bands appeared in all of the patterns, which indicated the existence of a highly conserved HindIII site. More complex hybridization results were obtained after HaeIII digestion. Twelve hybridization patterns were observed; three were characterized by a single hybridization band, and nine were characterized by double bands. Variations in hybridization patterns were observed in strains of both the same and different serotypes. The overall results at the gene level indicate that there is considerable heterogeneity among the streptokinases of group A streptococci, consistent with previous findings of immunological and chemical differences among streptokinases of group A streptococci.
进行了一项分子流行病学研究，以确定不同M型A组链球菌菌株及其他链球菌种中链激酶基因的分布。仅含有C组链球菌菌株H46A链激酶基因内部编码序列的质粒pNC1，被用作菌落杂交和Southern杂交实验中的DNA探针。只有致病性A、C和G组链球菌含有链激酶基因；其他12个兰斯菲尔德组菌株则没有。共检测了134株A组菌株，包括61种M型和6种T型。尽管通过酪蛋白 - 纤溶酶原覆盖试验检测，仅62%（134株中的83株）的菌株显示出阳性链激酶活性，但所有菌株均含有链激酶基因，这通过与pNC1探针的强杂交得以证明。对101株A组链球菌进行了Southern印迹DNA杂交。使用限制性内切酶HindIII和HaeIII消化基因组DNA。HindIII消化后观察到六种杂交模式。所有模式中均出现双杂交带，这表明存在一个高度保守的HindIII位点。HaeIII消化后获得了更复杂的杂交结果。观察到12种杂交模式；其中三种以单一杂交带为特征，九种以双带为特征。在相同和不同血清型的菌株中均观察到杂交模式的变化。基因水平的总体结果表明，A组链球菌的链激酶之间存在相当大的异质性，这与先前关于A组链球菌链激酶免疫和化学差异的研究结果一致。
