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The degradation effects and mechanism on gemfibrozil (GEM) in aqueous solution by dielectric barrier discharge (DBD) plasma combined with the catalyst CNTs/γFe2O3 are investigated. The concentrations of plasma‐generated reactive species, including H2O2, O3, NO3−, and OH, are measured with spectrophotometric and fluorescent probes. The effects of the plasma treatment period, discharge power, initial GEM concentration, solution pH value, conductivity, and the catalytic property are studied on the degradation rate and energy efficiency. Compared with the sole plasma treatment, CNTs/γFe2O3 could maximally improve the GEM degradation rate and energy efficiency to 99.7% ± 0.2% and 76.5 ± 5.2 mg·kW−1·h−1, respectively. The solution's total organic carbon removal efficiency has been increased to 47.2% ± 2.7%. Meanwhile, the possible degradation pathways of the plasma‐treated GEM solution and overall biological toxicity of GEM degradation intermediates and residual catalyst in solution are investigated. [ABSTRACT FROM AUTHOR]

The inactivation mechanism on multidrug-resistant Acinetobacter baumannii biofilms by atmospheric-pressure helium pulse discharge plasma jet and the effect on the biofilm regeneration capacity were studied. The initial total bacterial population was 7.37 ± 0.16 log10 colony forming unit (CFU)/mL in biofilms and about 99% of the A. baumannii biofilm cells lost their cultivability after 30 min of plasma treatment. Meanwhile, resazurin fluorescent staining method showed that about 80% of the biofilm cells lost their metabolic capacity, and some bacteria entered a viable but nonculturable state. In addition, 38.3% of the bacteria lost their membrane integrity in the light of SYTO 9/propidium iodide (PI) staining assay. According to H2DCFDA fluorescent staining, the concentration of reactive oxygen species (ROS) in bacteria after plasma exposure tended to initial state after a short increase. Moreover, in the study of the regeneration ability of A. baumannii after plasma exposure for 30 min, the total bacterial number after regeneration was 5.36 ± 0.20 log10 CFU/mL. Compared with the total number of cultivable bacteria in the first-generation biofilm, about 99.99% of the bacteria were inhibited. In comparison, the biomass of the regenerated biofilm decreased to (11.0 ± 1.0)%. Meanwhile, the percentage of metabolic bacteria decreased to (52.9 ± 1.0)%. These results indicated that atmospheric-pressure helium plasma jet could not only effectively inactivate bacteria in biofilms, but also inhibit the formation of the next generation biofilms. [ABSTRACT FROM AUTHOR]

The deactivation effects and mechanism of plasma‐activated water (PAW) against Staphylococcus aureus biofilm and the inhibitory effect on the biofilm regrowth capacity for the surviving S. aureus post PAW treatment were investigated in vitro. Systematic measurements on bacterial cultivability, metabolic capacity, membrane integrity and intracellular reactive oxygen species (ROS) concentration under two different experimental categories were carried out after PAW treatment. Considerable deactivation effects were discovered on biofilm S. aureus on both prolonging the PAW inducement or treatment time. The rising concentration of intracellular ROS and the PAW‐contained RS might exert synergistic effects in deactivating the biofilm S. aureus. Moreover, the biomass, bacterial cultivability and metabolic capacity of the regrown S. aureus biofilm all significantly declined along with the increasing PAW inducement or treatment time. Therefore, except for the short‐term rapid inactivation effects on the biofilm, the PAW treatment could also exert long‐term inhibitory effects on the regeneration of S. aureus biofilm. [ABSTRACT FROM AUTHOR]

The degradation effects and mechanism on gemfibrozil (GEM) in aqueous solution by dielectric barrier discharge (DBD) plasma combined with the catalyst CNTs/γFe2O3 are investigated. The concentrations of plasma‐generated reactive species, including H2O2, O3, NO3−, and OH, are measured with spectrophotometric and fluorescent probes. The effects of the plasma treatment period, discharge power, initial GEM concentration, solution pH value, conductivity, and the catalytic property are studied on the degradation rate and energy efficiency. Compared with the sole plasma treatment, CNTs/γFe2O3 could maximally improve the GEM degradation rate and energy efficiency to 99.7% ± 0.2% and 76.5 ± 5.2 mg·kW−1·h−1, respectively. The solution's total organic carbon removal efficiency has been increased to 47.2% ± 2.7%. Meanwhile, the possible degradation pathways of the plasma‐treated GEM solution and overall biological toxicity of GEM degradation intermediates and residual catalyst in solution are investigated. [ABSTRACT FROM AUTHOR]

Although CRISPR-Cas12a [clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein 12a] combining pre-amplification technology has the advantage of high sensitivity in biosensing, its generality and specificity are insufficient, which greatly restrains its application range. Here, we discovered a new targeting substrate for LbaCas12a (Lachnospiraceae bacterium Cas12a), namely double-stranded DNA (dsDNA) with a sticky-end region (PAM-SE+ dsDNA). We discovered that CRISPR-Cas12a had special enzymatic properties for this substrate DNA, including the ability to recognize and cleave it without needing a protospacer adjacent motif (PAM) sequence and a high sensitivity to single-base mismatches in that substrate. Further mechanism studies revealed that guide RNA (gRNA) formed a triple-stranded flap structure with the substrate dsDNA. We also discovered the property of low-temperature activation of CRISPR-Cas12a and, by coupling with the unique DNA hybridization kinetics at low temperature, we constructed a complete workflow for low-abundance point mutation detection in real samples, which was fast, convenient and free of single-stranded DNA (ssDNA) transformation. The detection limits were 0.005-0.01% for synthesized strands and 0.01-0.05% for plasmid genomic DNA, and the mutation abundances provided by our system for 28 clinical samples were in accordance with next-generation sequencing results. We believe that our work not only reveals novel information about the target recognition mechanism of the CRISPR-Cas12a system, but also greatly broadens its application scenarios., (© The Author(s) 2022. Published by Oxford University Press on behalf of Nucleic Acids Research.)