FALKOW S, WOHLHIETER J A, CITARELLA R V, BARON L S
J Bacteriol. 1964 Dec;88(6):1598-601. doi: 10.1128/jb.88.6.1598-1601.1964.
Falkow, Stanley (Walter Reed Army Institute of Research, Washington, D.C.), J. A. Wohlhieter, R. V. Citarella, and L. S. Baron. Transfer of episomic elements to Proteus. II. Nature of lac(+)Proteus strains isolated from clinical specimens. J. Bacteriol. 88:1598-1601. 1964.-Strains of Proteus mirabilis exhibiting the unusual property of utilizing lactose (lac(+)) have been reported in clinical material. A genetic examination discloses that the lac(+) determinants in these Proteus strains are associated with an infectious element, P, which is distinct from the sex factor of Escherichia coli K-12. The composite genetic element, P-lac, is readily transmissible to other enteric species and possesses properties which conform to those of an episomic element of the transfer variety. CsCl density-gradient studies of deoxyribonucleic acid (DNA) extracted from lac(+)P. mirabilis indicate that the P-lac(+) element did not arise in this species, but was acquired from an organism possessing a markedly different DNA base composition.
法尔科夫，斯坦利（华盛顿特区沃尔特·里德陆军研究所），J. A. 沃尔希特、R. V. 奇塔雷拉和L. S. 巴伦。附加体元件向变形杆菌的转移。II. 从临床标本中分离出的乳糖利用型（lac(+)）变形杆菌菌株的性质。《细菌学杂志》88:1598 - 1601。1964年。——在临床材料中已报道奇异变形杆菌菌株具有利用乳糖（lac(+)）这种不寻常的特性。遗传学检查表明，这些变形杆菌菌株中的lac(+)决定簇与一种感染性元件P相关，该元件与大肠杆菌K - 12的性因子不同。复合遗传元件P - lac很容易转移到其他肠道菌属，并且具有符合转移型附加体元件特性的性质。对从lac(+)奇异变形杆菌中提取的脱氧核糖核酸（DNA）进行的氯化铯密度梯度研究表明，P - lac(+)元件并非在该物种中产生，而是从一种具有明显不同DNA碱基组成的生物体中获得的。
