Stein D C
Department of Microbiology, University of Maryland, College Park 20742.
Can J Microbiol. 1991 May;37(5):345-9. doi: 10.1139/m91-056.
The 1600-bp (base pair) fragment encoding a portion of the nalidixic acid resistant DNA gyrase, subunit B, was characterized to determine what parameters effect transformation in the gonococcus. When this DNA (pSY2) was isolated from Escherichia coli, it was able to transform a variety of gonococcal strains to resistance to nalidixic acid via DNA-mediated transformation, irrespective of their restriction-modification phenotype. Nalidixic acid resistant transformants contained no plasmid DNA sequences that corresponded to the vector, as measured by plasmid screening procedures and colony hybridization techniques. Supercoiled and linear DNA transformed the gonococcus at the same efficiency. DNA fragments as small as 615 bp were able to transform the gonococcus. The presence of a 10-bp uptake sequence enhanced a DNA fragment's ability to transform the gonococcus by four orders of magnitude. When the fragment encoding the nalidixic acid resistant DNA gyrase was subcloned into M13mp18, both the replicative form and the single-stranded form of the phage were able to transform the gonococcus to nalidixic acid resistance.
对编码耐萘啶酸的DNA促旋酶B亚基的1600碱基对片段进行了表征，以确定哪些参数会影响淋球菌的转化。当从大肠杆菌中分离出这种DNA（pSY2）时，它能够通过DNA介导的转化使多种淋球菌菌株对萘啶酸产生抗性，而不论其限制修饰表型如何。通过质粒筛选程序和菌落杂交技术测定，耐萘啶酸的转化子不包含与载体相对应的质粒DNA序列。超螺旋DNA和线性DNA转化淋球菌的效率相同。小至615碱基对的DNA片段能够转化淋球菌。一个10碱基摄取序列的存在使DNA片段转化淋球菌的能力提高了四个数量级。当将编码耐萘啶酸的DNA促旋酶的片段亚克隆到M13mp18中时，噬菌体的复制型和单链型都能够使淋球菌对萘啶酸产生抗性。
