论文部分内容阅读
质粒是细菌染色体外的双股环状DNA,广泛存在于50多个属的细菌中,编码很多重要生物学性状,能在同种、同属、甚至不同属细菌间转移,容易自然丢失或经人工处理而消除。质粒的存在对于细菌的生命活动并非必需,但是质粒基因的产物参与细菌的很多生理活动。最近Mobley等证明斯氏菌(P.stuartii)BE 2467株分解蔗糖和尿素的基因位于该菌携带的一个82Kb的质粒上。他们还证明分解乳糖的斯氏菌AO4T株携带一种编码乳糖酶的150Kb大质粒。当这些质粒丢失后便导致细菌的生化特性变异。R质粒的存在使宿主菌能抵抗重金属、多种抗生
Plasmids, which are bacterial extrachromosomal circular double-stranded DNA, are present in more than 50 genera of bacteria and encode a number of important biological traits that transfer between the same species, their generic genus, or even their nonspecific bacterial species, easily and naturally lost, Disposal and eliminate. The presence of plasmids is not essential for bacterial life activities, but the products of the plasmid genes are involved in many physiological activities of bacteria. Recently, Mobley et al. Demonstrated that the gene for the decomposition of sucrose and urea by P. stuartii BE 2467 strain is located on an 82 Kb plasmid carried by the bacterium. They also demonstrated that the lipolytic Staphylococcus aureus AO4T strain carries a large 150 kb plasmid encoding lactase. When these plasmids are lost, the biochemical characteristics of the bacteria are mutated. The presence of R plasmid allows the host bacteria to resist heavy metals, a variety of antibiotics