Development of a marine compatible biological assay for mutagenic compounds

One of the primary negative effects of environmental oil exposure is the potential for mutagenic, or DNA damaging effects. This can lead to heritable genetic damage in higher organisms with long-term environmental impact. The biological effect of contamination is difficult to estimate on the basis of chemical profiles due to the complexity of environmental samples. Thus, biologically based assays give a closer approximation of the actual ecological impacts of contamination. To measure the mutagenic or DNA damaging potential of samples we currently utilize the Microscreen Assay, which is based upon a strain of Escherichia coli that is sensitive to mutagenic compounds in a dose-specific way. However, this strain is not optimized for marine samples because E. coli is adapted for growth in freshwater environments. As a consequence the detection limit with this assay is fairly high allowing the possibility of false negative results. We developed an analogous assay utilizing a cultured marine strain. We screened marine bacterial isolates and marine viruses to develop a marine bacterial strain that is sensitive to mutagenic contaminants in a dose specific manner that will increase the sensitivity and decrease the detection threshold for mutagenic contaminants in marine environments.

环境原油暴露的主要负面影响之一，是其可能引发诱变效应（即DNA损伤效应）。此类效应可能在高等生物体内造成可遗传的遗传损伤，并带来长期的环境影响。由于环境样品的复杂性，仅依据化学特征难以评估污染物的生物学效应。因此，基于生物学的检测方法能够更贴近地反映污染物实际产生的生态影响。为检测样品的诱变或DNA损伤潜力，当前我们采用微筛选检测法（Microscreen Assay），该方法基于一株对诱变化合物具有剂量特异性敏感性的大肠杆菌（Escherichia coli）菌株。然而，该菌株并非针对海洋样品优化设计，因为大肠杆菌适宜在淡水环境中生长。因此该检测方法的检出限相对较高，存在出现假阴性结果的可能。为此我们开发了一种类似的检测方法，采用培养得到的海洋菌株。我们通过筛选海洋细菌分离株与海洋病毒，成功开发出一株对诱变污染物具有剂量特异性敏感性的海洋细菌菌株，该菌株能够提升海洋环境中诱变污染物的检测灵敏度并降低其检出阈值。