Schmidt G, Jann B, Jann K, Orskov I, Orskov F
J Gen Microbiol. 1977 Jun;100(2):355-61. doi: 10.1099/00221287-100-2-355.
Most of the his+ hybrids from crosses between the Escherichia coli donor Hfr45(O8:K27) and different E. coli O9 recipients expressed the donor O8 antigen specificity and produced the capsular antigen K27. Therefore these hybrids must have inherited the his-linked donor rfb region determining the synthesis of O8- specific polysaccharides as well as his-linked genes involved in K27 antigen synthesis. In the living state these hybrids were inagglutinable in O8 antiserum like the donor cells. However, when E. coli K12 and O8:K42- were used as recipients most of the his+ hybrids were agglutinable in O8 and K27 antisera. The amounts of K27 antigen present in these hybrids, designated as K27i (intermediate) forms, were sufficient to evoke the production of K27 antibodies in rabbits, but insufficient to inhibit O-agglutination of the respective cells. The additional transfer of the trp region of E. coli O8:K27 into such K27i forms frequently resulted in O-inagglutinable K27+ hybrids. This is attributed to the introduction of trp-linked genes which apparently play a role in the synthesis of K27 capsular antigen. Tus it is concluded that at least two gene loci, one close to his and the other close to trp, are required for the synthesis of the complete capsular antigen K27.
大多数来自大肠杆菌供体Hfr45（O8:K27）与不同大肠杆菌O9受体杂交产生的his+杂种表达供体O8抗原特异性并产生荚膜抗原K27。因此，这些杂种必定继承了与his相连的供体rfb区域，该区域决定O8特异性多糖的合成，以及与his相连的参与K27抗原合成的基因。在存活状态下，这些杂种像供体细胞一样在O8抗血清中不凝集。然而，当使用大肠杆菌K12和O8:K42-作为受体时，大多数his+杂种在O8和K27抗血清中可凝集。这些杂种中存在的K27抗原量，被指定为K27i（中间）形式，足以在兔体内引发K27抗体的产生，但不足以抑制相应细胞的O凝集。将大肠杆菌O8:K27的trp区域额外转移到这种K27i形式中，常常导致O不凝集的K27+杂种。这归因于trp相连基因的引入，这些基因显然在K27荚膜抗原的合成中起作用。因此得出结论，完整荚膜抗原K27的合成至少需要两个基因位点，一个靠近his，另一个靠近trp。
