Applications of whole-cell bacterial sensors in biotechnology and environmental science.
Biosensors have major advantages over chemical or physical analyses with regard to specificity, sensitivity, and portability. Recently, many types of whole-cell bacterial biosensors have been developed using recombinant DNA technology. The bacteria are genetically engineered to respond to the presence of chemicals or physiological stresses by synthesizing a reporter protein, such as luciferase, beta-galactosidase, or green fluorescent protein. In addition to an overview of conventional biosensors, this minireview discusses a novel type of biosensor using a photosynthetic bacterium as the sensor strain and the crtA gene, which is responsible for carotenoid synthesis, as the reporter. Since bacteria possess a wide variety of stress-response mechanisms, including antioxidation, heat-shock responses, nutrient-starvation, and membrane-damage responses, DNA response elements for several stress-response proteins can be fused with various reporter genes to construct a versatile set of bacterial biosensors for a variety of analytes. Portable biosensors for on-site monitoring have been developed using a freeze-dried biosensing strain, and cell array biosensors have been designed for high-throughput analysis. Moreover, in the future, the use of single-cell biosensors will permit detailed analyses of samples. Signals from such sensors could be detected with digital imaging, epifluorescence microscopy, and/or flow cytometry.
Yagi
Kiyohito
K
Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka, 565-0871, Japan. yagi@phs.osaka-u.ac.jp
D001419:Bacteria / Q000235:genetics* / Q000254:growth & development; D015374:Biosensing Techniques / Q000379:methods*; D001709:Biotechnology / Q000379:methods*; D004463:Ecology / Q000379:methods*; D005818:Genetic Engineering; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
D049452:Green Fluorescent Proteins; D008156:Luciferases; D001616:beta-Galactosidase