Objective To develop an automated system for the determination of gross α and gross β activity concentrations in water, and to support the rapid and automated monitoring of environmental water bodies. Methods Based on the thick source method, microwave evaporation-ashing was used to replace conventional electric hotplate heating. A grinder and a sample-spreading device were designed and operated via a robotic arm, achieving fully automated pretreatment, sample preparation, and measurement. Results Spike recovery tests demonstrated that the recovery rates were 95.7%-102.5% for gross α and 97.2%-108.1% for gross β. The relative standard deviations were 4.1%-7.8% for gross α and 5.9%-7.7% for gross β. Compared with manual laboratory methods, the average relative errors were 2.17%-6.25% for gross α and 4.17%-6.90% for gross β. The sample preparation time was reduced from an average of 72 hours to less than 5 hours, representing an efficiency improvement of over 90%. Conclusion The developed system enables rapid, accurate, and fully automated monitoring of gross α/β radioactivity, making it suitable for online monitoring of environmental water bodies. It can provide timely data on the radiological indicators of water bodies for environmental protection and water resource management authorities.

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.