Ottawa Laboratory (Fallowfield), Canadian Food Inspection Agency, Ottawa, Ontario, Canada.
J Environ Sci Health B. 2010 May;45(4):279-84. doi: 10.1080/03601231003704556.
Composting was investigated as a means for safe disposal of organic waste containing bacteria that carry transgenes in recombinant plasmids. To generate model recombinant plasmids, a mobile IncQ plasmid, RSF1010, and a non-mobile plasmid, pGFP, were genetically modified to carry a DNA segment encoding both green fluorescent protein and kanamycin resistance and were designated as RSF1010-GFPK and pGFPK. Escherichia coli (E. coli) C600 harboring these plasmids were inoculated into chicken manure specimens that were placed in compost at 20 and 60 cm from the bottom of a 1.0-m high compost bin. Control specimens were held at ambient temperature. By day 10, compost temperatures at the lower and upper levels of the bin had reached 45.3 and 61.5 degrees C, respectively, and at both levels the target E. coli had been inactivated and the plasmids had lost their capacity to be transformed or mobilized. Furthermore, based on real time Polymerase chain reaction (PCR), the transgene fragments along with the host chromosomal DNA fragment from specimens at the upper level had been degraded beyond the detection limit. However, at the lower level where temperatures remained below 48 degrees C these fragment persisted to day 21. At ambient temperatures (0-8 degrees C), the E. coli, plasmids and the transgene fragments persisted in manure specimens throughout the 21 day test period. The study showed the potential for composting as a safe procedure for disposal of bacteria carrying transgenes in recombinant plasmids.
堆肥被研究作为一种安全处理含有携带重组质粒中转基因细菌的有机废物的方法。为了生成模型重组质粒，一种可移动的 IncQ 质粒 RSF1010 和一种非移动质粒 pGFP 被遗传修饰以携带编码绿色荧光蛋白和卡那霉素抗性的 DNA 片段，并分别命名为 RSF1010-GFPK 和 pGFPK。携带这些质粒的大肠杆菌 (E. coli) C600 被接种到鸡粪标本中，这些标本被放置在堆肥中，距离堆肥箱底部 20 厘米和 60 厘米处。对照标本在环境温度下保存。到第 10 天，堆肥箱底部和顶部的温度分别达到 45.3 和 61.5 摄氏度，在这两个水平上，目标大肠杆菌已被灭活，质粒已失去转化或移动的能力。此外，基于实时聚合酶链反应 (PCR)，在上层标本中，与宿主染色体 DNA 片段一起的转基因片段已被降解到检测限以下。然而，在温度仍低于 48 摄氏度的下层，这些片段持续到第 21 天。在环境温度（0-8 摄氏度）下，大肠杆菌、质粒和转基因片段在粪便标本中持续存在整个 21 天的测试期。该研究表明，堆肥作为一种安全处理携带重组质粒中转基因细菌的方法具有潜力。
