中文摘要：

为了解环境因素对质粒DNA热处理效率的影响以及热处理过程的有效性和安全性,以pET-28b质粒为材料,采用定量PCR技术结合质粒转化等方法分析了pH、NaCl、牛血清白蛋白（BSA）及EDTA浓度等因素对质粒DNA热处理的影响.结果表明,NaCl、BSA及EDTA的存在对热处理过程中的质粒DNA具有保护作用,且保护作用依次增强.在纯水中热处理30min后的质粒DNA可扩增的片段数仅是在0.1%的EDTA中热处理30min后质粒DNA可扩增片段数目的1.7%.由于生物实验室废水中通常含有上述有机或无机物质,因此,实际热处理过程中质粒DNA的降解半衰期可能远长于先前报道的2.7～4min,残留的转化活性也可能更高,这必须引起我们高度关注.但是,研究结果也表明,酸性条件下的热处理能加速质粒DNA的失活和降解,因此建议热处理过程可在弱酸性条件下完成,以强化其处理效果.

英文摘要：

The main method for treating wastewater containing recombinant DNA from biological laboratories is heating at 100℃for 3-5 min. The treatment efficiency of the waste recombinant gene fragments can be interfered with by multiple factors, so it is important to figure out the impacts of different environmental factors on the decay efficiency of plasmid DNA during the thermo-treatment process. Plasmid pET-28b was used as an example to investigate the decay efficiency during the thermo-treatment process under different conditions including pH and different NaCl,bovine serum albumin （BSA） and EDTA concentrations. Quantitative PCR plus plasmid transformation technology were used to measure the effectiveness of the treatment. The experimental results showed that low pH conditions promote the decay of plasmid DNA during the thermo-treatment process. NaCl, BSA and especially EDTA all protect the DNA from being degraded. The number of template copies of plasmid DNA remaining after thermo-treating in distilled water for 30 min was 1.7% of that in 1% （W/V） EDTA solution. The wastewater from biological laboratories usually contains the above-mentioned organic and inorganic materials. So the half-life of plasmid DNA during thermo-treatment could be longer than 2.7-4 min in practical situations, suggesting we must pay attention to this possibility.