Brownell G H, Adams J N
J Bacteriol. 1967 Sep;94(3):650-9. doi: 10.1128/jb.94.3.650-659.1967.
The segregation of unselected genes expressing resistance or susceptibility to acriflavine, erythromycin, streptomycin, and tetracycline was analyzed in selected prototrophic recombinants resulting from matings of Nocardia erythropolis and N. canicruria. The organisms were shown to be functionally haploid and appeared to contain not more than one genome. It was postulated that all observed genes were present in a linear linkage group. The ordering of the genes in N. erythropolis was: tetB10 eryB9 his-3 purA1 acr-2 strA1 (respectively, resistance to tetracycline and erythromycin, deficiency for histidine and for purine, and resistance to acriflavine and streptomycin). The ordering of the genes in N. canicruria was: purB2 tetA9 eryA7 acr-11 strB2 (respectively, deficiency for purine, and resistance to tetracycline, erythromycin, acriflavine, and streptomycin). Excluding the genes for acriflavine resistance, acr-2 and acr-11, resistance loci in N. erythropolis were not allelic to and showed lateral displacement from genes controlling phenotypically similar resistance in N. canicruria. Evidence for some lack of homology between N. erythropolis and N. canicruria genomes was found. Recombination phenomena between the nocardial species was postulated to occur as a result of formation of a heterogenomic zygote in which new combinations were produced. Production of selectable, haploid recombinants was ascribed to subsequent haploidization of the zygote.
在由红斑诺卡氏菌和犬诺卡氏菌交配产生的选定原养型重组体中，分析了表达对吖啶黄、红霉素、链霉素和四环素耐药或敏感的未选择基因的分离情况。结果表明，这些生物体在功能上是单倍体，似乎包含不超过一个基因组。据推测，所有观察到的基因都存在于一个线性连锁群中。红斑诺卡氏菌中基因的顺序为：tetB10 eryB9 his-3 purA1 acr-2 strA1（分别为对四环素和红霉素的抗性、组氨酸和嘌呤缺陷以及对吖啶黄和链霉素的抗性）。犬诺卡氏菌中基因的顺序为：purB2 tetA9 eryA7 acr-11 strB2（分别为嘌呤缺陷以及对四环素、红霉素、吖啶黄和链霉素的抗性）。排除对吖啶黄抗性的基因acr-2和acr-11，红斑诺卡氏菌中的抗性位点与犬诺卡氏菌中控制表型相似抗性的基因不是等位基因，并且显示出横向位移。发现了红斑诺卡氏菌和犬诺卡氏菌基因组之间存在一些缺乏同源性的证据。推测诺卡氏菌种间的重组现象是由于形成了一个异基因组合子，其中产生了新的组合。可选择的单倍体重组体的产生归因于合子随后的单倍体化。
