Petänen Tiina, Romantschuk Martin
Department of Biosciences, Division of General Microbiology, University of Helsinki, P.O. Box 56, FIN-00014, Finland.
Chemosphere. 2003 Jan;50(3):409-13. doi: 10.1016/s0045-6535(02)00505-2.
The overall toxicity of soil, and the bioavailability and arsenite from soil were measured with the constructed constitutively luminescent strain Pseudomonas fluorescens OS8 (pNEP01) and with earlier published biosensor strains P. fluorescens OS8 (pTPT11) for mercury and P. fluorescens OS8 (pTPT31) for arsenite, respectively. Both spiked and authentic samples were studied. By combining bacterial assays enabled partial analysis of reasons for toxicity of environmental samples, some of which were highly toxic despite containing little or no heavy metals. The spiked soils were not toxic overall but the method of measuring concentration from water-extractable fraction or from soil-water slurry affected the results significantly. Mercury that was bound to clay even after water extraction was nevertheless found to be bioavailable to a high degree to the biosensor bacteria. Since induction of the luminescence genes takes place intracellularly the bacteria may able to apparently release mercury when in direct contact with clay particle. This type of biomobilisation was not observed with arsenite spiked soils. The same phenomenon was detected in one of the environmental samples.
利用构建的组成型发光菌株荧光假单胞菌OS8（pNEP01）以及先前发表的分别用于检测汞的生物传感器菌株荧光假单胞菌OS8（pTPT11）和用于检测亚砷酸盐的荧光假单胞菌OS8（pTPT31），测定了土壤的总体毒性以及土壤中亚砷酸盐的生物有效性。对加标样品和真实样品均进行了研究。通过结合细菌检测，能够对环境样品毒性的原因进行部分分析，其中一些样品尽管几乎不含或不含重金属，但毒性却很高。加标土壤总体上无毒，但从水可提取部分或土壤 - 水悬浮液中测量浓度的方法对结果有显著影响。即使经过水提取后与粘土结合的汞，对生物传感器细菌而言仍具有很高的生物可利用性。由于发光基因的诱导发生在细胞内，细菌在与粘土颗粒直接接触时可能能够明显地释放汞。在加标亚砷酸盐的土壤中未观察到这种生物活化现象。在其中一个环境样品中也检测到了相同的现象。
