Whole-cell luminescence-based flow-through biodetector for toxicity testing

Abstract

A new type of biodetector was designed based on a bioluminescence test with the bacterium Vibrio fischeri performed in a liquid continuous flow-through system. Here we describe the modification of a commercial tube luminescence detector to work in the flow mode by building a new flow cell holder and a new case including "top cover" to connect the flow cell with the waste and the incubation capillary in a light-proof manner. As different samples were injected successively it was necessary to keep the individual peaks separated. This was done using an air-segmented flow in the reaction coil. To afford fast screening, the incubation time of the sample and the Vibrio fischeri, which equaled the dead time of the detection system, was set at 5.6 min. Rapid monitoring of toxic substances is achieved by using 20 microL of sample and flow-rates of 110-150 microL min(-1). As a proof-of-principle, we show results for the detection of five selected di-, tri- and tetrachlorophenols at different concentrations varying from 1 to 200 mg L(-1). Calculation of inhibition rates and EC50 values were performed and compared with corresponding values from the DIN EN ISO 11348-2 microplate format. Compared with the latter, the inhibition rates obtained with our flow-through biodetector for the compounds tested were generally about twofold lower, but importantly, a much faster detection is possible.

Immobilisation and Biosensors

“…Thus it could be a case where the light intensity produced by a microbe would decrease on interaction with a toxic compound. A Vibrio fi scheri -based microbial biosensor was developed on the same principle for the determination of toxicity of some common environmental pollutants in a continuous fl ow system (Stolper et al 2008 ). A bioluminescent biosensor using Pseudomonas fl uorescens HK44 pUTK21 recognition element has been designed to detect the available fraction of naphthalene in soil since there was a linear relationship between the luminescence from the microbe and naphthalene concentration (Paton et al 2009 ).…”

Hyphenated TLC as a Tool in the Effect-Directed Discovery of Bioactive Natural Products

“…A HPLC method has been online hyphenated to a chemical assay (i.e., a DPPH free radical scavenging assay) [7,8], and even to enzymic assays (i.e., a cholinesterase inhibitory assay) [9,10]. In regard to bacterial cell assays, only Aliivibrio fischeri bacteria cells have been introduced directly to HPLC effluent [11], although the cell death increased with the amount of methanol in the eluent. Hyphenation of these methods using HPLC leads to the dilution of analytes with reagents and the use of long reaction coils resulting in extra peak broadening [9].…”

Applied Microbiology

“…A Vibrio fi scheri -based microbial biosensor was developed on the same principle for the determination of toxicity of some common environmental pollutants in a continuous fl ow system (Stolper et al 2008 ). Thus it could be a case where the light intensity produced by a microbe would decrease on interaction with a toxic compound.…”