Winstanley C, Morgan J A, Pickup R W, Saunders J R
Department of Genetics and Microbiology, University of Liverpool, United Kingdom.
Appl Environ Microbiol. 1991 Jul;57(7):1905-13. doi: 10.1128/aem.57.7.1905-1913.1991.
IncQ marker plasmids were previously constructed to enable the analysis of the survival of populations of Pseudomonas putida released into lake water (C. Winstanley, J. A. W. Morgan, R. W. Pickup, J. G. Jones, and J. R. Saunders, Appl. Environ. Microbiol. 55:771-777, 1989). We constructed equivalent IncP plasmids, pLV1016 and pLV1017, to provide conjugative alternative systems. Detection of the xylE gene carried by marker plasmids was found to be a valid indicator to use for studying the survival of released populations by culturing on nonselective media. These plasmids were used to study the survival of populations of Pseudomonas putida in both sterile and untreated lake water. The effects of inoculum size, the metabolic burden imposed on the cell by the unregulated expression of xylE, and an auxotrophic mutation carried by the host strain were studied. We also assessed the reproducibility and hence the predictability of the survival of released populations. Model systems with a single lake water sample and model systems with three different lake water samples, taken from the same site in consecutive months, were used to analyze variability between replicates and to assess differences caused by host strain or water sample. A large variability was found depending on which water sample was used. These findings imply that it will be difficult to predict accurately the survival of released populations in the natural environment.
IncQ标记质粒先前已构建完成，用于分析释放到湖水中的恶臭假单胞菌群体的存活情况（C. 温斯坦利、J. A. W. 摩根、R. W. 皮卡普、J. G. 琼斯和J. R. 桑德斯，《应用与环境微生物学》55:771 - 777，1989年）。我们构建了等效的IncP质粒pLV1016和pLV1017，以提供接合替代系统。通过在非选择性培养基上培养发现，标记质粒携带的xylE基因的检测是用于研究释放群体存活情况的有效指标。这些质粒被用于研究恶臭假单胞菌群体在无菌湖水和未处理湖水中的存活情况。研究了接种量、xylE的无调控表达对细胞施加的代谢负担以及宿主菌株携带的营养缺陷型突变的影响。我们还评估了释放群体存活情况的可重复性以及因此的可预测性。使用来自同一地点连续数月采集的单一湖水样本的模型系统和具有三种不同湖水样本的模型系统，来分析重复样本之间的变异性，并评估由宿主菌株或水样引起的差异。根据所使用的水样不同，发现存在很大的变异性。这些发现意味着准确预测释放群体在自然环境中的存活情况将很困难。
