Lee-Wickner L J, Chassy B M
Appl Environ Microbiol. 1985 May;49(5):1154-61. doi: 10.1128/aem.49.5.1154-1161.1985.
Four small cryptic plasmids were isolated from Lactobacillus casei strains, and restriction endonuclease maps of these plasmids were constructed. Three of the small plasmids (pLZ18C, pLZ19E, and pLZ19F1; 6.4, 4.9, and 4.8 kilobase pairs, respectively) were cloned into Escherichia coli K-12 by using pBR322, pACYC184, and pUC8 as vectors. Two of the plasmids, pLZ18C and pLZ19E, were also cloned into Streptococcus sanguis by using pVA1 as the vector. Hybridization by using nick-translated cloned 32P-labeled L. casei plasmid DNA as the probe revealed that none of the cryptic plasmids had appreciable DNA-DNA homology with the large lactose plasmids found in the L. casei strains, with chromosomal DNAs isolated from these strains. Partial homology was detected among several plasmids isolated from different strains, but not among cryptic plasmids isolated from the same strain.
从干酪乳杆菌菌株中分离出4个小的隐蔽质粒，并构建了这些质粒的限制性内切酶图谱。其中3个小质粒（分别为pLZ18C、pLZ19E和pLZ19F1，大小分别为6.4、4.9和4.8千碱基对）通过使用pBR322、pACYC184和pUC8作为载体克隆到大肠杆菌K-12中。另外两个质粒pLZ18C和pLZ19E也通过使用pVA1作为载体克隆到血链球菌中。以缺口平移法克隆的32P标记的干酪乳杆菌质粒DNA为探针进行杂交，结果显示，这些隐蔽质粒与干酪乳杆菌菌株中发现的大乳糖质粒以及从这些菌株中分离的染色体DNA均无明显的DNA-DNA同源性。在从不同菌株分离的几个质粒之间检测到部分同源性，但在从同一菌株分离的隐蔽质粒之间未检测到同源性。
