Rajini Rani D B, Mahadevan A
Centre for Advanced Studies in Botany, University of Madras, India.
Biometals. 1992 Summer;5(2):73-80. doi: 10.1007/BF01062217.
Pseudomonas sp isolated from the Bay of Bengal (Madras coast) contained a single large plasmid (pMR1) of 146 kb. Plasmid curing was not successful with mitomycin C, sodium dodecyl sulfate, acridine orange, nalidixic acid or heat. Transfer of mercury resistance from marine Pseudomonas to Escherichia coli occurred during mixed culture incubation in liquid broth at 10(-4) to 10(-5) ml(-1). However, transconjugants lacked the plasmid pMR1 and lost their ability to resist mercury. Transformation of pMR1 into E. coli competent cells was successful; however, the efficiency of transformation (1.49 x 10(2)Hgr transformants microsgm-1 pMR1 DNA) was low. E. coli transformants containing the plasmid pMR1 conferred inducible resistance to mercury, arsenic and cadmium compounds similar to the parental strain, but with increased expression. The mercury resistant transformants exhibited mercury volatilization activity. A correlation existed between metal and antibiotic resistance in the plasmid pMR1.
从孟加拉湾（马德拉斯海岸）分离出的假单胞菌含有一个146 kb的大型质粒（pMR1）。用丝裂霉素C、十二烷基硫酸钠、吖啶橙、萘啶酸或加热处理均未能成功消除质粒。在液体肉汤中于10^(-4)至10^(-5) ml^(-1)混合培养孵育期间，海洋假单胞菌的汞抗性转移至大肠杆菌。然而，转接合子缺乏质粒pMR1并失去了抗汞能力。将pMR1转化至大肠杆菌感受态细胞成功；然而，转化效率（1.49×10^2 Hg^r转化子/μg pMR1 DNA）较低。含有质粒pMR1的大肠杆菌转化子赋予了对汞、砷和镉化合物的诱导抗性，类似于亲本菌株，但表达增加。抗汞转化子表现出汞挥发活性。质粒pMR1中的金属抗性与抗生素抗性之间存在相关性。
