Bulgakova T N, Totolian A A
Mol Gen Mikrobiol Virusol. 1990 Oct(10):23-5.
Transposon-mediated mutability has been used to isolate the isogenic strains of the group B serotype Ia streptococci with the mutations in the genes coding for the production of capsular antigen. The transconjugants have lost the ability to bind type Ia antiserum as demonstrated by immunoblotting technique. The loss of type-specific antigen by the strains has resulted in a dramatic decrease in virulence for mice while the absorbtion indexes of transconjugants increased 2-3 fold. The mutant clones deficient in capsule expression had the increased buoyant density in the percoll gradient as compared with the parent strains of group B. The stable mutants impaired in ability to produce the polysaccharide capsule on the cell surface were obtained as a result of site-specific insertion of transposon Tn916 into the genome of group B serotype I streptococcus.
转座子介导的突变已被用于分离B组血清型Ia链球菌的同基因菌株，这些菌株在编码荚膜抗原产生的基因中发生了突变。如免疫印迹技术所示，转接合子失去了结合Ia型抗血清的能力。这些菌株型特异性抗原的丧失导致其对小鼠的毒力急剧下降，而转接合子的吸收指数增加了2至3倍。与B组亲本菌株相比，缺乏荚膜表达的突变克隆在Percoll梯度中的浮力密度增加。通过将转座子Tn916位点特异性插入B组血清型I链球菌的基因组，获得了在细胞表面产生多糖荚膜能力受损的稳定突变体。
