title: Development of Colorimetric-Based Whole-Cell Biosensor for Organophosphorus Compounds by Engineering Transcription Regulator DmpR.
abstract: It is useful for whole-cell biosensors to be based on colorimetric detection because the output signal can be easily visualized. However, colorimetric-based whole-cell biosensors suffer higher detection limits as compared to bioluminescence- or fluorescence-based biosensors. In this work, we attempt to reduce the detection limit for a colorimetric-based whole-cell biosensor by applying directed evolution techniques on a transcription regulator, DmpR, to alter the expression level of its cognate promoter, which was fused to mRFP1 to output red coloration in the presence of organophosphate pesticides containing a phenolic group. We selected the two best-performing mutants, DM01 and DM12, which were able to develop red coloration in the presence of parathion as low as 10 μM after just 6 h of induction at 30 °C. This suggests that engineering of the transcription regulator in the sensing domain is useful for improving various properties of whole-cell biosensors, such as reducing the detection limit for simple colorimetric detection of organophosphate pesticides.
authors.affiliation: Temasek Laboratories, National University of Singapore 117411, Singapore.
authors.forename: Huiqing
authors.initials: H
authors.lastname: Chong
authors.affiliation: Temasek Laboratories, National University of Singapore 117411, Singapore.|Department of Chemical and Biomolecular Engineering, National University of Singapore 117585, Singapore.
authors.forename: Chi Bun
authors.initials: CB
authors.lastname: Ching
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D015374:Biosensing Techniques; D002238:Carbohydrate Epimerases / Q000235:genetics / Q000378:metabolism; D003124:Colorimetry; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D005278:Fenitrothion / Q000032:analysis; D017353:Gene Deletion; D017930:Genes, Reporter; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D009596:Nitrophenols / Q000032:analysis; D009943:Organophosphorus Compounds / Q000032:analysis*; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic; D015202:Protein Engineering; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D000097573:Red Fluorescent Protein
chemical_list: D001426:Bacterial Proteins; D002238:Carbohydrate Epimerases; D005278:Fenitrothion; D008164:Luminescent Proteins; D009596:Nitrophenols; D009943:Organophosphorus Compounds; D015534:Trans-Activators; D000097573:Red Fluorescent Protein; C080133:DmpR protein, Pseudomonas; C037213:ADP-L-glycero-D-mannoheptose-6-epimerase; C024836:4-nitrophenol
keywords: DmpR; biosensor; colorimetric detection; organophosphates; pesticides