Baumberg S, Mountain A
J Gen Microbiol. 1984 May;130(5):1247-52. doi: 10.1099/00221287-130-5-1247.
Mutations in Bacillus subtilis 168 have been isolated that confer resistance to arginine hydroxamate in the presence, but not absence, of ornithine. Seven such Ahor mutants have been studied in detail. In common with certain classes of Ahr mutant (resistant to arginine hydroxamate in the absence of arginine precursors) described previously, these Ahor mutants showed little or no inducibility of enzymes of arginine catabolism. Mutants that showed no inducibility were unable to utilize arginine or ornithine as sole nitrogen source. The only biosynthetic enzyme to show any consistent differences in activity from the parent was ornithine carbamoyltransferase, whose level was slightly elevated in cells grown in the presence of ornithine or citrulline. PBS1 transduction crosses showed that two of the ahor mutations map at the ahrA locus, while a third (unique in its resistance to arginine hydroxamate in the presence of citrulline) mapped at a hitherto undescribed locus closely linked to metC, designated ahrD.
已分离出枯草芽孢杆菌168的突变体，这些突变体在有鸟氨酸存在但无鸟氨酸时能赋予对精氨酸异羟肟酸的抗性。已对七个这样的Ahor突变体进行了详细研究。与先前描述的某些类型的Ahr突变体（在没有精氨酸前体的情况下对精氨酸异羟肟酸有抗性）一样，这些Ahor突变体显示出精氨酸分解代谢酶的诱导性很低或没有诱导性。没有诱导性的突变体无法利用精氨酸或鸟氨酸作为唯一氮源。与亲本相比，唯一在活性上表现出任何一致差异的生物合成酶是鸟氨酸氨甲酰基转移酶，其水平在有鸟氨酸或瓜氨酸存在的情况下生长的细胞中略有升高。PBS1转导杂交表明，两个ahor突变位于ahrA位点，而第三个（在有瓜氨酸存在的情况下对精氨酸异羟肟酸的抗性独特）位于一个迄今未描述的与metC紧密连锁的位点，命名为ahrD。
