Davies J K, Reeves P
J Bacteriol. 1975 Jul;123(1):102-17. doi: 10.1128/jb.123.1.102-117.1975.
By using each of the available colicins, we have isolated a large number of colicin-resistant mutants. They included both receptor and tolerant mutants and each was screened for cross-resistance to all other colicins. On the basis of the cross-resistance of these mutants it was possible to place known colicins into two mutually exclusive groups, group A and group B. Mutants selected as resistant to colicins of group A may or may not be cross-resistant to other colicins of group A, BUT Are never resistant to colicins of group B. The reverse also applies. The mutants isolated as resistant to colicins of group A (A, E1, E2, E3, K, L, N, S4, and X) have been divided into 21 phenotypic classes on the basis of their colicin resistance patterns. These include most of the tolerant and receptor mutants previously isolated, some of which were previously shown to also have an increased sensitivity to certain antibiotics and detergents. Type strains from each of the phenotypic classes were therefore tested for sensitivity to a range of antibiotics, detergents, and surfactants that included all those previously used. With these new data, it has been possible to speculate informatively on the mode of action of the different colicins. We have confirmed the position of previously isolated mutations on the Escherichia coli K-12 genetic map, and located approximately the loci conferring colicin resistance in some of the newly isolated mutants.
通过使用每种可用的大肠杆菌素，我们分离出了大量抗大肠杆菌素的突变体。它们包括受体突变体和耐受突变体，并且对每个突变体都进行了针对所有其他大肠杆菌素的交叉抗性筛选。基于这些突变体的交叉抗性，有可能将已知的大肠杆菌素分为两个相互排斥的组，A组和B组。被选为对A组大肠杆菌素具有抗性的突变体可能对A组的其他大肠杆菌素具有交叉抗性，也可能不具有交叉抗性，但对B组的大肠杆菌素永远不具有抗性。反之亦然。被分离为对A组大肠杆菌素（A、E1、E2、E3、K、L、N、S4和X）具有抗性的突变体，根据它们的大肠杆菌素抗性模式已被分为21个表型类别。这些类别包括先前分离出的大多数耐受突变体和受体突变体，其中一些先前已显示对某些抗生素和去污剂也具有更高的敏感性。因此，对每个表型类别的典型菌株进行了对一系列抗生素、去污剂和表面活性剂的敏感性测试，这些物质包括所有先前使用过的物质。有了这些新数据，就有可能对不同大肠杆菌素的作用模式进行有益的推测。我们已经在大肠杆菌K-12遗传图谱上确定了先前分离出的突变的位置，并在一些新分离出的突变体中大致定位了赋予大肠杆菌素抗性的基因座。
