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The strategies to relieve antibiotic resistance genes (ARGs) pollution are urgently needed. Fermentation broth from fruit and vegetable waste (FFVW), an agricultural amendment, exhibits a remarkable capacity to reduce ARG pollution; however, the underlying mechanism of this effect remains unclear. We performed microcosm experiments to reappear the phenomenon of FFVW-driven reduction in ARGs. Moderate-level FFVW reduced gene resistance to sulfonamide (41.2 %), macrolide–lincosamide–streptogramin (MLS) (47.2 %), chloramphenicol (63.2 %), and tetracycline (61.4 %). Binning and network analyses revealed that Actinobacteria comprise the primary hosts of ARGs in arable soil, and FFVW substantially inhibited the growth and metabolic activity of these organisms. Moreover, tetracycline and MLS production was partially/completely inhibited by FFVW, further reducing the transfer frequency by 52.9–86.1 % and 46.6–66.6 % in the intragenic and intergenic mating systems, respectively. Furthermore, the expression of genes related to conjugation pairing and plasmid transfer was downregulated. Thus, FFVW effectively reduces ARG pollution by inhibiting Actinobacteria proliferation, thereby reducing selective pressure and restricting horizontal gene transfer. Our findings highlight the important underlying mechanisms of FFVW involved in ARG reduction, supporting its use in arable soil. [Display omitted] • The mechanism of FFVW-mediated ARG reduction was revealed from macro and micro perspectives. • FFVW reduced ARGs by restraining the growth and metabolism for ARG host Actinobacteria in soils. • FFVW reduced ARGs by reducing the persistent antibiotics selection pressure in soils. • FFVW mitigated horizontal transfer of ARGs through conjugative transfer. • The study offered an approach to control soil ARGs caused by organic fertilizer application. [ABSTRACT FROM AUTHOR]

Concerns regarding biological risk in environment have garnered increasing attention. Manure has been believed to be a significant source of antibiotic resistance genes (ARGs) in agricultural soil. Nevertheless, the profile of microbial contamination including ARGs, virulence factor genes (VFGs) and human bacterial pathogens (HBPs) in different manure-amended soils remain largely unknown. Here, we conducted the systematic metagenome-based study to explore changes in resistome, VFGs and HBPs in soils treated by frequently-used manures. The results revealed that many manure-borne ARGs, VFGs, and HBPs could be spreaded into soils, and their diversity and abundance were significantly different among chemical fertilizer, pig manure, chicken manure, cow dung and silkworm excrement application. A total of 157 potential HBPs accounting about 1.33% of total bacteria were detected. The main ARGs transferred from manures to soil conferred resistance to vancomycin and macrolide-lincosamide-streptogramin. The series analysis revealed positive co-occurrence patterns of ARGs-HBPs, VFGs-HBPs and ARGs-VFGs. Microbial contamination were more serious in pig manure and silkworm excrement sample than in the other samples, implying the usage of these two manures increased the risk of HBPs and dissemination of ARGs. This study confirmed the prevalence and discrepancy of resistome, VFGs and HBPs in different manure-amended soils. [Display omitted] • A total of 157 potential human bacterial pathogens were detected, accounting about 1.33% of total bacteria screened. • Abundant and diverse virulence factor genes and antibiotic resistance genes were identified in the agricultural soils. • The coexistence of many antibiotic resistance genes and virulence factor genes was found in human bacterial pathogens. • Pig manure and silkworm excrement increased higher microbiological risks in farmland soil. [ABSTRACT FROM AUTHOR]

The coexistence of antibiotic resistance genes (ARGs), mobile genetic elements (MGEs), and virulence factor genes (VFGs) in human bacterial pathogens (HBPs) increases their risks to ecological security and human health and no effective strategy is available. Herein, we demonstrated two typical quorum sensing (QS) interfering agents, 4-nitropyridine-N-oxide (4-NPO, a QS inhibitor) and Acylase Ⅰ (a quorum quenching (QQ) enzyme), effectively decreased the abundance of HBPs by 48.30% and 72.54%, respectively, which was accompanied by the reduction of VFGs, ARGs, and MGEs. The decrease in QS signals mediated by QS interfering agents disturbed bacterial communication and inhibited biofilm formation. More importantly, QS interfering agents reduced the intra-species and inter-species conjugation frequencies among bacteria, considerably inhibiting the dissemination of ARGs and VFGs via horizontal gene transfer. Furthermore, the QS interfering agents did not significantly affect the metabolic function of other nonpathogenic microorganisms in the soil. Collectively, our study provides an effective and eco-friendly strategy to mitigate the risks of HBPs in soil. [Display omitted] • 4-NPO and Acylase Ⅰ decreased the abundance of HBPs by 48.30% and 72.54%. • 4-NPO and Acylase I decreased the concentration of QS signals. • The dissemination of ARGs and VFGs via horizontal gene transfer was inhibited. • 4-NPO and Acylase I did not impact the metabolic function of microorganisms in soil. [ABSTRACT FROM AUTHOR]

Abstract: The aim of this paper is to provide new experimental data of the minimum ignition energy (MIE) of gaseous nitromethane/air mixtures to discuss the explosion pressure and the flame temperature as a function of nitromethane concentration. Observations on the influence of nitromethane concentration on combustion pressure and temperature through the pressure and temperature measure system show that peak temperature (the peak of combustion temperature wave) is always behind peak pressure (the peak of the combustion pressure wave) in arrival time, the peak combustion pressure of nitromethane increases in the range of its volume fraction 10–40% as the concentration of nitromethane increases, and it slightly decreases in the range of 40–50%. The maximum peak pressure is equal to 0.94MPa and the minimum peak pressure 0.58MPa. Somewhat similar to the peak pressure, the peak combustion temperature increases with the volume fraction of nitromethane in the range of 10–40%, and slightly decreases in 40–50%. The maximum peak temperature is 1340°C and the minimum 860°C. The combustion temperature rise rate increases with the concentration of nitromethane in 10–30%, while decreases in 30–50% and its maximum value of combustion temperature rise rate in 10–50% is 4200°C/s at the volume fraction of 30%. Influence of the concentration of nitromethane on the combustion pressure rise rate is relatively complicated, and the maximum value of rise rate of combustion pressure wave in 10–50% is 11MPa/s at the concentration 20%. [ABSTRACT FROM AUTHOR]