A new strategy using an arnperometric biosensor with Escherichia coli （E. coli） that provides a rapid toxicity determination of chemical compounds is described. The CellSense biosensor system comprises a biological ...A new strategy using an arnperometric biosensor with Escherichia coli （E. coli） that provides a rapid toxicity determination of chemical compounds is described. The CellSense biosensor system comprises a biological component immobilized in intimate contact with a transducer which converts the biochemical signal into a quantifiable electrical signal. Toxicity assessment of heavy metals using E.coli biosensors could be finished within 30 min and the 50% effective concentrations （ECso） values of four heavy metals were determined. The results shows that inhibitory effects of four heavy metals to E.coli can be ranked in a decreasing order of Hg^2＋ 〉 Cu^2＋ 〉 Zn^2＋ 〉 Ni^2＋, which accords to the results of conventional bacterial counting method. The toxicity test of organic compounds by using CellSense biosensor was also demonstrated. The CellSense biosensor with E. coli shows a good, reproducible behavior and can be used for reproducible measurements.展开更多
The prediction and assessment of environmental pollution by arsenic are important preconditions of advocating environmental protection and human health risk assessment. A yellow fluorescent protein-based whole-cell bi...The prediction and assessment of environmental pollution by arsenic are important preconditions of advocating environmental protection and human health risk assessment. A yellow fluorescent protein-based whole-cell biosensor for the detection of arsenite and arsenate was constructed and tested. An arsenic-resistant promoter and the regulatory gene arsR were obtained by PCR from the genome ofEscherichia coli DH5ct, andphiYFP was introduced into E. coli DH5ct as a reporter gene to construct an arsenic-resistant whole-cell biosensor （WCB-11） in which phiYFP was expressed well for the first time. Experimental results demonstrated that the biosensor has a good response to arsenic and the expression ofphiYFP. When strain WCB-11 was exposed to As^3＋ and As^5＋, the expression of yellow fluorescence was time-dependent and dose-dependent. This engineered construct is expected to become established as an inexpensive and convenient method for the detection of arsenic in the field.展开更多
Detection of N-acyl homoserine lactones （AHLs） is useful for understanding quorum sensing （QS） behaviors, including biofilm formation, virulence and metabolism. For detecting AHLs and indicating the host cells in ...Detection of N-acyl homoserine lactones （AHLs） is useful for understanding quorum sensing （QS） behaviors, including biofilm formation, virulence and metabolism. For detecting AHLs and indicating the host cells in situ, we constructed the plasmid pUCGMA2T1-4 to make a dual fluorescent whole- cell biosensor based on the AhlI/R AHL system of Pseudomonas syringae pv. syringae B728a. The plasmid contains three components： constitutively expressed enptll：：gfP for indicating host cells, Pahll：：mcherry that produces red fluorescence in response to AHL, and the ahIR gene that encodes an AHL regulatory protein. Meanwhile, two copies of T1-4 （four tandem copies of a transcriptional terminator） were added into the plasmid to reduce background. The results showed that when the plasmid was placed into Escherichia coli, the dual fluorescence whole-cell biosensor was able to respond with red fluorescence within 6 hr to 5 × 10^-8-1 × 10^-5 mol/L of 3OC6-HSL. Bright green fluorescence indicated the host cells. Furthermore, when the plasmid was transferred to wild- type Pseudomonas PhTA125 （an AHL-producing bacterium）, it also showed both green and red fluorescence. This result demonstrates that this plasmid can be used to construct whole-cell indicators that can indicate the AHL response and spatial behaviors of microbes in a mi tal niche展开更多
基金supported by the National Natural Science Foundation of China(No.20707014)the Program for Young Excellent Talents of Tongji University.
文摘A new strategy using an arnperometric biosensor with Escherichia coli （E. coli） that provides a rapid toxicity determination of chemical compounds is described. The CellSense biosensor system comprises a biological component immobilized in intimate contact with a transducer which converts the biochemical signal into a quantifiable electrical signal. Toxicity assessment of heavy metals using E.coli biosensors could be finished within 30 min and the 50% effective concentrations （ECso） values of four heavy metals were determined. The results shows that inhibitory effects of four heavy metals to E.coli can be ranked in a decreasing order of Hg^2＋ 〉 Cu^2＋ 〉 Zn^2＋ 〉 Ni^2＋, which accords to the results of conventional bacterial counting method. The toxicity test of organic compounds by using CellSense biosensor was also demonstrated. The CellSense biosensor with E. coli shows a good, reproducible behavior and can be used for reproducible measurements.
基金supported by the National Natural Science Foundation of China (No. 20707035,20777089)the National High Technology Research and Development Program (863) of China (No. 2007AA06A407)
文摘The prediction and assessment of environmental pollution by arsenic are important preconditions of advocating environmental protection and human health risk assessment. A yellow fluorescent protein-based whole-cell biosensor for the detection of arsenite and arsenate was constructed and tested. An arsenic-resistant promoter and the regulatory gene arsR were obtained by PCR from the genome ofEscherichia coli DH5ct, andphiYFP was introduced into E. coli DH5ct as a reporter gene to construct an arsenic-resistant whole-cell biosensor （WCB-11） in which phiYFP was expressed well for the first time. Experimental results demonstrated that the biosensor has a good response to arsenic and the expression ofphiYFP. When strain WCB-11 was exposed to As^3＋ and As^5＋, the expression of yellow fluorescence was time-dependent and dose-dependent. This engineered construct is expected to become established as an inexpensive and convenient method for the detection of arsenic in the field.
基金supported by the National Natural Science Foundation of China (No. 2117145)
文摘Detection of N-acyl homoserine lactones （AHLs） is useful for understanding quorum sensing （QS） behaviors, including biofilm formation, virulence and metabolism. For detecting AHLs and indicating the host cells in situ, we constructed the plasmid pUCGMA2T1-4 to make a dual fluorescent whole- cell biosensor based on the AhlI/R AHL system of Pseudomonas syringae pv. syringae B728a. The plasmid contains three components： constitutively expressed enptll：：gfP for indicating host cells, Pahll：：mcherry that produces red fluorescence in response to AHL, and the ahIR gene that encodes an AHL regulatory protein. Meanwhile, two copies of T1-4 （four tandem copies of a transcriptional terminator） were added into the plasmid to reduce background. The results showed that when the plasmid was placed into Escherichia coli, the dual fluorescence whole-cell biosensor was able to respond with red fluorescence within 6 hr to 5 × 10^-8-1 × 10^-5 mol/L of 3OC6-HSL. Bright green fluorescence indicated the host cells. Furthermore, when the plasmid was transferred to wild- type Pseudomonas PhTA125 （an AHL-producing bacterium）, it also showed both green and red fluorescence. This result demonstrates that this plasmid can be used to construct whole-cell indicators that can indicate the AHL response and spatial behaviors of microbes in a mi tal niche
