Biosensors have become powerful tools for real-time monitoring of specific small molecules and precise control of gene expression in biological systems. High-throughput sensors for 1, 4-butanediamine biosynthesis can greatly improve the screening efficiency of high-yielding 1, 4-butanediamine strains. However, the strategies for adapting the characteristics of biosensors are still rarely studied, which limits the applicability of 1, 4-butanediamine biosensors. In this paper, we propose the development of a 1, 4-butanediamine biosensor based on the transcriptional regulator PuuR, whose homologous operator puuO is installed in the constitutive promoter P_gapA of Escherichia coli to control the expression of the downstream superfolder green fluorescent protein (sfGFP) as the reporter protein. Finally, the biosensor showed a stable linear relationship between the GFP/OD₆₀₀ value and the concentration of 1, 4-butanediamine when the concentration of 1, 4-butanediamine was 0-50 mmol/L. The promoters with different strengths in the E. coli genome were used to modify the 1, 4-butanediamine biosensor, and the functional properties of the PuuR-based 1, 4-butanediamine biosensor were explored and improved, which laid the groundwork for high-throughput screening of engineered strains highly producing 1, 4-butanediamine.
Biosensing Techniques/methods* ; Escherichia coli/metabolism* ; Promoter Regions, Genetic/genetics* ; Green Fluorescent Proteins/metabolism* ; Transcription Factors/genetics* ; Escherichia coli Proteins/genetics* ; Diamines/metabolism* ; Gene Expression Regulation, Bacterial

OBJECTIVE To study the disinfectant resistance of multi-drug resistant Escherichia coli strains isolated clinically,and to find out the efficacy of disinfectants commonly used in killing multi-drug resistant E.coli strains.METHODS Minimal inhibitory concentration(MIC) and suspension quantitative germicidal test were used.Compared with standard strains,strains of multi-drug resistant E.coli isolated clinically were determined the resistance to four kinds of disinfectants including benzalkonium bromide etc.RESULTS A higher MIC of benzalkonium bromide compared with standard strains was observed in 61.9% of all 21 multi-drug resistant E.coli strains,and as for povidone iodine and NaClO,the ratio was 71.4% and 14.3%,respectively.All multi-drug resistant E.coli strains had the same MICs of peroxyacetic acid with standard strains.The above-mentioned 4 disinfectants commonly used at the routine concentrations killed 100% of the resistant strains of E.coli within 5 minutes.CONCLUSIONS The resistance to benzalkonium bromide and povidone iodine of multi-drug resistant E.coli isolated clinically is higher than standard strains;and 4 kinds of disinfectants commonly used are effective for multi-drug resistant E.coli strains isolated clinically.