VERFAHREN ZUM NACHWEIS VON QUECKSILBER MIT HILFE VON DURCH QUECKSILBER ZU ERHOEHTER BIOLUMINESZENZ ANGEREGTER MIKROORGANISMEN

摘要

Process in which microorganisms equiped with a plasmid vector, pGL4, constructed by molecular biological techniques, can be used as biosensors for mercury compounds. A gene complex (mer-Operon) inductible by mercury ions is combined by molecular cloning with the luciferase (LUX) gene system of Vibrio Harveyi. The arrangement of the two gene units is designed so that the mer-Operon promoter, which is positively regulated by mercury compounds, also controls the transcription of the LUX genes. As a result, microorganisms transformed with plasmid pGL4 respond to increasing quantities of mercury cations in the surrounding medium with an increase in their emitted bioluminescence. The process is absolutely specific for mercury, rapid and highly sensitive: the proven limit for mercury ions is approximately 0.2 ppb, i.e., 5 times lower than the detection threshold for the most powerful established methods (atomic absorption spectrometry), which detect 1 to 5 ppb of mercury and require a considerable quantity of apparatus. A further advantage of the invention is the possibility of determining measurement values (bioluminescence signals emitted by microorganisms transformed by plasmid pGL4) without direct contact between the biosensor and the signal-amplification unit (bioluminescence apparatus). The method therefore permits simple, continuous, on-line determination of critical mercury concentrations.