MULCHING - Word Related Documents




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807300.9004Film mulching reduces antibiotic resistance genes in the phyllosphere of lettuce. Phyllosphere is an important reservoir of antibiotic resistance genes (ARGs), but the transfer mechanism of ARGs from soil and air to phyllosphere remains unclear. This study demonstrated that soil-air-phyllosphere was the dominant ARG transfer pathway, and blocking it by film mulching can reduce typical phyllosphere ARGs in lettuce by 80.7% - 98.7% (89.5% on average). To further eliminate phyllosphere ARGs in lettuce grown with film mulching, the internal soil-endosphere-phyllosphere transfer pathway deserves more attention. We analyzed the ARG hosts and the resistome in lettuce rhizosphere and phyllosphere with film mulching via hybrid Illumina-Nanopore sequencing. Pseudomonas sp. 7SR1 was more abundant than other ARG hosts, accounting for 1.0% and 47.1% of the total bacteria in rhizosphere and phyllosphere, respectively. The species has flagella that can promote mobility and can excrete extracellular polymeric substances and/or surfactant-like microbial products, which benefits its colonization in the phyllosphere. Impeding the migration of Pseudomonas sp. 7SR1 via the soil-endosphere-phyllosphere pathway would be effective to further reduce ARGs in phyllosphere. Multidrug resistant genes were predominant in phyllosphere (40.3% of the total), and 87.6% of the phyllosphere ARGs were located on chromosomes, indicating relatively low horizontal gene transfer (HGT) potentials. This study provides insights into the transfer mechanism, hosts, and control strategies of phyllosphere ARGs in typical plants.202234955195
812610.8996Antiallergic drugs drive the alteration of microbial community and antibiotic resistome in surface waters: A metagenomic perspective. Antiallergic drugs (AADs) are emerging contaminants of global concern due to their environmental persistence and potential ecological impacts. This study investigated the effects of seven AADs (chlorpheniramine, diphenhydramine, cetirizine, loratadine, desloratadine, sodium cromoglicate and calcium gluconate) at environmentally relevant concentrations on antibiotic resistome and bacterial community structures in water using microcosm experiments and metagenomic sequencing. The results showed that AADs increased the abundance of antibiotic-resistant bacteria (ARB) by 1.24- to 7.78-fold. Community structure shifts indicated that chlorpheniramine, diphenhydramine, and cetirizine promoted Actinobacteria (e.g., Aurantimicrobium), while the other four AADs favored Proteobacteria (e.g., Limnohabitans). AADs also significantly altered the relative abundance of antibiotic resistance genes (ARGs), with Actinobacteria and Proteobacteria identified as key ARB components and potential hosts of ARGs (e.g., evgS, mtrA, RanA). Host analysis showed ARGs were primarily carried by Actinobacteria (e.g., Aurantimicrobium) under chlorpheniramine, diphenhydramine, and cetirizine exposure, but by Proteobacteria (e.g., Limnohabitans) under the other four AADs. Furthermore, AADs facilitated the horizontal transfer of ARGs (e.g., evgS) within microbial communities, contributing to antibiotic resistance dissemination. This study highlights the ecological risks of AADs in promoting antibiotic resistance spread and provides new insights into their impact on microbial communities and resistome dynamics in aquatic environments.202540570627
787720.8993External circuit loading mode regulates anode biofilm electrochemistry and pollutants removal in microbial fuel cells. This study investigated the effects of different external circuit loading mode on pollutants removal and power generation in microbial fuel cells (MFC). The results indicated that MFC exhibited distinct characteristics of higher maximum power density (P(max)) (named MFC-HP) and lower P(max) (named MFC-LP). And the capacitive properties of bioanodes may affect anodic electrochemistry. Reducing external load to align with the internal resistance increased P(max) of MFC-LP by 54.47 %, without no obvious effect on MFC-HP. However, intermittent external resistance loading (IER) mitigated the biotoxic effects of sulfamethoxazole (SMX) (a persistent organic pollutant) on chemical oxygen demand (COD) and NH(4)(+)-N removal and maintained high P(max) (424.33 mW/m(2)) in MFC-HP. Meanwhile, IER mode enriched electrochemically active bacteria (EAB) and environmental adaptive bacteria Advenella, which may reduce antibiotic resistance genes (ARGs) accumulation. This study suggested that the external circuit control can be effective means to regulate electrochemical characteristics and pollutants removal performance of MFC.202439153696
788230.8992Insights into antibiotic resistance gene abundances and regulatory mechanisms induced by ionic liquids during composting. This study investigated the regulatory mechanism of the evolution of antibiotic resistance genes (ARGs) during the composting process with sawdust and cow manure as raw materials using ionic liquids (ILs) pretreatment. The results showed that genes of MLS, chloramphenicol, tetracycline, beta - lactam as composting gradually decreased. From day0 to day3, MLS in control group (CK) and experimental group (T) decreased by 25.62% and 26.66%, respectively. Tetracycline decreased by 7.21% in CK and by 7.86% in T. Chloramphenicol decreased by 2.85% in CK and 3.34% in T. Beta-lactam decreased by 1.95% in Ck and by 3.69% in T. Mechanism studies have shown that ILs can effectively decompose extracellular polymeric substances (EPS) and enhance lactose dehydrogenase (LDH) release, resulting in ARGs release and elimination. Meanwhile, ILs pretreatment can inhibit growth of some ARGs hosts, especially Firmicutes, resulting in decreased ARGs. Moreover, metabolic pathways and related genes take part in ARGs transmission were down regulated, leading to decreased ARGs.202337481880
787140.8987Effects of different quaternary ammonium compounds on intracellular and extracellular resistance genes in nitrification systems under the pre-contamination of benzalkyl dimethylammonium compounds. As the harm of benzalkyl dimethylammonium compounds (BACs) on human health and environment was discovered, alkyltrimethyl ammonium compound (ATMAC) and dialkyldimethyl ammonium compound (DADMAC), which belong to quaternary ammonium compounds (QACs), were likely to replace BACs as the main disinfectants. This study simulated the iterative use of QACs to explore their impact on resistance genes (RGs) in nitrification systems pre-contaminated by BACs. ATMAC could initiate and maintain partial nitrification. DADMAC generated higher levels of reactive oxygen species and lactate dehydrogenase, leading to increased biological toxicity in bacteria. The abundance of intracellular RGs of sludge was higher with the stress of QACs. DADMAC also induced higher extracellular polymeric substance secretion. Moreover, it facilitated the transfer of RGs from sludge to water, with ATMAC disseminating RGs through si-tnpA-04 and DADMAC through si-intI1. Sediminibacterium might be potential hosts for RGs. This study offered insights into disinfectant usage in the post-COVID-19 era.202539612960
774550.8987Iron-modified biochar boosts anaerobic digestion of sulfamethoxazole pharmaceutical wastewater: Performance and microbial mechanism. The accumulation of volatile fatty acids (VFAs) caused by antibiotic inhibition significantly reduces the treatment efficiency of sulfamethoxazole (SMX) wastewater. Few studies have been conducted to study the VFAs gradient metabolism of extracellular respiratory bacteria (ERB) and hydrogenotrophic methanogen (HM) under high-concentration sulfonamide antibiotics (SAs). And the effects of iron-modified biochar on antibiotics are unknown. Here, the iron-modified biochar was added to an anaerobic baffled reactor (ABR) to intensify the anaerobic digestion of SMX pharmaceutical wastewater. The results demonstrated that ERB and HM were developed after adding iron-modified biochar, promoting the degradation of butyric, propionic and acetic acids. The content of VFAs reduced from 1166.0 mg L(-1) to 291.5 mg L(-1). Therefore, chemical oxygen demand (COD) and SMX removal efficiency were improved by 22.76% and 36.51%, and methane production was enhanced by 6.19 times. Furthermore, the antibiotic resistance genes (ARGs) such as sul1, sul2, intl1 in effluent were decreased by 39.31%, 43.33%, 44.11%. AUTHM297 (18.07%), Methanobacterium (16.05%), Geobacter (6.05%) were enriched after enhancement. The net energy after enhancement was 0.7122 kWh m(-3). These results confirmed that ERB and HM were enriched via iron-modified biochar to achieve high efficiency of SMX wastewater treatment.202337030222
811960.8979Biochar-amended composting of lincomycin fermentation dregs promoted microbial metabolism and reduced antibiotic resistance genes. Improper disposal of antibiotic fermentation dregs poses a risk of releasing antibiotics and antibiotic resistant bacteria to the environment. Therefore, this study evaluated the effects of biochar addition to lincomycin fermentation dregs (LFDs) composting. Biochar increased compost temperature and enhanced organic matter decomposition and residual antibiotics removal. Moreover, a 1.5- to 17.0-fold reduction in antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs) was observed. Adding biochar also reduced the abundances of persistent ARGs hosts (e.g., Streptomyces, Pseudomonas) and ARG-related metabolic pathways and genes (e.g., ATP-binding cassette type-2 transport, signal transduction and multidrug efflux pump genes). By contrast, compost decomposition improved due to enhanced metabolism of carbohydrates and amino acids. Overall, adding biochar into LFDs compost reduced the proliferation of ARGs and enhanced microbial community metabolism. These results demonstrate that adding biochar to LFDs compost is a simple and efficient way to decrease risks associated with LFDs composting.202336334868
798970.8977Feasibility of sulfate-calcined eggshells for removing pathogenic bacteria and antibiotic resistance genes from landfill leachates. High abundance of human pathogen and antibiotic resistance genes (ARGs) in landfill leachate has become an emerging threat against human health. Therefore, sulfate- and calcination-modified eggshells as green agricultural bioresource were applied to test the feasibility of removing pathogenic bacteria and ARGs from leachate. The highest removal of Escherichia coli (E. coil) and gentamycin resistant gene (gmrA) from artificial contaminated landfill leachate was achieved by the application of eggshell with combined treatment of sulfate and calcination. The 16S and gmrA gene copies of E. coil declined significantly from 1.78E8±8.7E6 and 4.12E8±5.9E6 copies mL(-1) to 1.32E7±2.6E6 and 2.69E7±7.2E6 copies mL(-1), respectively, within 24h dynamic adsorption equilibrium process (p<0.05). Moreover, according to the Langmuir kinetic model, the greatest adsorption amount (1.56×10(9) CFU E. coil per gram of modified eggshells) could be obtained at neutral pH of 7.5. The optimal adsorption eggshells were then screened to the further application in three typical landfill leachates in Nanjing, eastern China. Significant decrease in species and abundance of pathogenic bacteria and ARGs (tet, sul, erm, qnr, and ampC) indicated its great efficiency to purify landfill leachates. This study demonstrated that sulfate-calcined eggshells can be an environmentally-friendly and highly efficient bioadsorbent to the management of reducing dissemination risk of pathogen and ARGs in landfill leachate.201728343745
789780.8972Enhanced removal of antibiotic and antibiotic resistance genes by coupling biofilm electrode reactor and manganese ore substrate up-flow microbial fuel cell constructed wetland system. Manganese ore substrate up-flow microbial fuel cell constructed wetland (UCW-MFC(Mn)) as an innovative wastewater treatment technology for purifying antibiotics and electricity generation with few antibiotic resistance genes (ARGs) generation has attracted attention. However, antibiotic purifying effects should be further enhanced. In this study, a biofilm electrode reactor (BER) that needs direct current driving was powered by a Mn ore anode (UCW-MFC(Mn)) to form a coupled system without requiring direct-current source. Removal efficiencies of sulfadiazine (SDZ), ciprofloxacin (CIP) and the corresponding ARGs in the coupled system were compared with composite (BER was powered by direct-current source) and anaerobic systems (both of BER and UCW-MFC were in open circuit mode). The result showed that higher antibiotic removal efficiency (94% for SDZ and 99.1% for CIP) in the coupled system was achieved than the anaerobic system (88.5% for SDZ and 98.2% for CIP). Moreover, electrical stimulation reduced antibiotic selective pressure and horizontal gene transfer potential in BER, and UCW-MFC further reduced ARG abundances by strengthening the electro-adsorption of ARG hosts determined by Network analysis. Bacterial community diversity continuously decreased in BER while it increased in UCW-MFC, indicating that BER mitigated the toxicity of antibiotic. Degree of modularity, some functional bacteria (antibiotic degrading bacteria, fermentative bacteria and EAB), and P450 enzyme related to antibiotic and xenobiotics biodegradation genes were enriched in electric field existing UCW-MFC, accounting for the higher degradation efficiency. In conclusion, this study provided an effective strategy for removing antibiotics and ARGs in wastewater by operating a BER-UCW-MFC coupled system.202337437616
853290.8972Simultaneous volatile fatty acids promotion and antibiotic resistance genes reduction in fluoranthene-induced sludge alkaline fermentation: Regulation of microbial consortia and cell functions. The impact and mechanism of fluoranthene (Flr), a typical polycyclic aromatic hydrocarbon highly detected in sludge, on alkaline fermentation for volatile fatty acids (VFAs) recovery and antibiotic resistance genes (ARGs) transfer were studied. The results demonstrated that VFAs production increased from 2189 to 4272 mg COD/L with a simultaneous reduction of ARGs with Flr. The hydrolytic enzymes and genes related to glucose and amino acid metabolism were provoked. Also, Flr benefited for the enrichment of hydrolytic-acidifying consortia (i.e., Parabacteroides and Alkalibaculum) while reduced VFAs consumers (i.e., Rubrivivax) and ARGs potential hosts (i.e., Rubrivivax and Pseudomonas). Metagenomic analysis indicated that the genes related to cell wall synthesis, biofilm formation and substrate transporters to maintain high VFAs-producer activities were upregulated. Moreover, cell functions of efflux pump and Type IV secretion system were suppressed to inhibit ARGs proliferation. This study provided intrinsic mechanisms of Flr-induced VFAs promotion and ARGs reduction during alkaline fermentation.202438266788
7832100.8972Reduction of antibiotics and antibiotic resistance genes in simulated-sunlight-supported counter-diffusion bacteria-Algae biofilms: Interface properties and functional gene responses. A novel bacteria-algae symbiotic counter-diffusion biofilm system integrated within simulated-sunlight (designated UV-MABAR) was engineered to simultaneously address antibiotic residuals and antibiotic resistance genes (ARGs) while maintaining functional microbial consortia under simulated solar irradiation. The non-algal control system (UV-MABR) demonstrated elevated repulsion energy barriers accompanied by significant suppression of ATP synthase (p < 0.01) and DNA repair-related gene clusters, leading to biofilm homeostasis disruption and subsequent sulfamethoxazole (SMX) effluent accumulation peaking at 138.11±2.34 μg/L. In contrast, the UV-MABAR configuration exhibited dynamic quenching of tyrosine-associated fluorescence moieties within extracellular polymeric substances, thereby diminishing complexation potential with SMX aromatic rings and achieving 70.75 %±3.21 % abiotic photodegradation efficiency, which substantially curtailed ARG proliferation pathways, promoting a significant downregulation of sul1 (-1.9 log(2) fold-change) and sul2 (-1.1 log(2) fold-change) expression compared to conventional MABR controls. Besides, algal in UV-MABAR attenuated the irradiation-induced α-helix/(β-sheet + random coil) conformational shift, moderating biofilm matrix compaction. Crucially, algal proliferation up-regulated bacterial recA expression (1.7-fold increase), thereby preserving catabolic gene integrity and preventing endogenous substances release. These protective measures kept effluent concentrations of SMX, NH(4)(+)-N, total nitrogen, and COD in UV-MABAR at 19.84 μg/L, 3.88 mg/L, 12.76 mg/L, and 34.97 mg/L, respectively, during 150 days of operation.202540738088
7859110.8972Abatement of antibiotics and resistance genes during catalytic ozonation enhanced sludge dewatering process: Synchronized in volume and hazardousness reduction. Based on the efficiency of the catalytic ozonation techniques (HDWS+O(3) and MnFe(2)O(4) @SBC+O(3)) in enhancing the sludge dewaterability, the effectiveness in synchronized abatement antibiotics and antibiotic resistance genes (ARGs) was conducted to determine. The results revealed that catalytic ozonation conditioning altered the distribution of target antibiotics (tetracycline (TC), oxytetracycline (OTC), norfloxacin (NOR), ofloxacin (OFL)) in the dewatered filtrate, the dewatered sludge cake and the extra-microcolony/cellular polymers (EMPS/ECPS) layers, achieving the redistribution from solid-phase adsorption to liquid-phase dissolution. The total degradation rate was over 90% for TC and OTC, 72-78% for NOR and OFL; the abatement efficiency of eleven ARGs reached 1.47-3.01 log and 1.64-3.59 log, respectively, and more than four eARGs were eliminated. The effective abatement of the absolute abundance of Mobile genetic elements (MGEs) (0.91-1.89 log) demonstrated that catalytic ozonation conditioning could also significantly inhibit horizontal gene transfer (HGT). The abundance of resistant bacteria was greatly reduced and the signal transduction of the typical ARGs host bacteria was inhibited. The highly reactive oxidation species (ROS) generated were responsible for the abatement of antibiotics and ARGs. These findings provided new insights into the sludge conditioning for ideal and synchronized reduction in volume and hazardousness by catalytic ozonation processes in sludge treatment.202437944236
7893120.8969Removal of ofloxacin and inhibition of antibiotic resistance gene spread during the aerobic biofilm treatment of rural domestic sewage through the micro-nano aeration technology. Micro-nano aeration (MNA) has great potential for emerging contaminant removal. However, the mechanism of antibiotic removal and antibiotic resistance gene (ARG) spread, and the impact of the different aeration conditions remain unclear. This study investigated the adsorption and biodegradation of ofloxacin (OFL) and the spread of ARGs in aerobic biofilm systems under MNA and conventional aeration (CVA) conditions. Results showed that the MNA increased OFL removal by 17.27 %-40.54 % and decreased total ARG abundance by 36.37 %-54.98 %, compared with CVA. MNA-induced biofilm rough morphology, high zeta potential, and reduced extracellular polymeric substance (EPS) secretion enhanced OFL adsorption. High dissolved oxygen and temperature, induced by MNA-enriched aerobic bacteria and their carrying OFL-degrading genes, enhanced OFL biodegradation. MNA inhibited the enrichment of ARG host bacteria, which acquired ARGs possibly via horizontal gene transfer (HGT). Functional profiles involved in the HGT process, including reactive oxygen species production, membrane permeability, mobile genetic elements (MGEs), adenosine triphosphate synthesis, and EPS secretion, were down-regulated by MNA, inhibiting ARG spread. Partial least-squares path modeling revealed that MGEs might be the main factor inhibiting ARG spread. This study provides insights into the mechanisms by which MNA enhances antibiotic removal and inhibits ARG spread in aerobic biofilm systems.202539733752
7888130.8968Microecology of aerobic denitrification system construction driven by cyclic stress of sulfamethoxazole. The construction of aerobic denitrification (AD) systems in an antibiotic-stressed environment is a serious challenge. This study investigated strategy of cyclic stress with concentration gradient (5-30 mg/L) of sulfamethoxazole (SMX) in a sequencing batch reactor (SBR), to achieve operation of AD. Total nitrogen removal efficiency of system increased from about 10 % to 95 %. Original response of abundant-rare genera to antibiotics was changed by SMX stress, particularly conditionally rare or abundant taxa (CRAT). AD process depends on synergistic effect of heterotrophic nitrifying aerobic denitrification bacteria (Paracoccus, Thauera, Hypomicrobium, etc). AmoABC, napA, and nirK were functionally co-expressed with multiple antibiotic resistance genes (ARGs) (acrR, ereAB, and mdtO), facilitating AD process. ARGs and TCA cycling synergistically enhance the antioxidant and electron transport capacities of AD process. Antibiotic efflux pump mechanism played an important role in operation of AD. The study provides strong support for regulating activated sludge to achieve in situ AD function.202438710419
8108140.8968Insights into the beneficial effects of woody peat for reducing abundances of antibiotic resistance genes during composting. Antibiotic resistance genes (ARGs) in manure endangered human health, while heavy metals in manure will pose selective pressure on ARGs. This study explored the effects on ARGs of adding woody peat during composting at different ratios (0 (CK), 5% (T1), and 15% (T2)). After composting, the relative abundances of 8/11 ARGs were 6.97-38.09% and 10.73-54.31% lower in T1 and T2, respectively, than CK. The bioavailable Cu content was 1.40% and 18.40% lower in T1 and T2, respectively, than CK. Network analysis showed that ARGs, mobile genetic elements (MGEs), and metal resistance genes possessed common potential host bacteria, such as Streptococcus, Dietzia, and Corynebacterium_1. Environmental factors, especially bioavailable Cu, and MGEs accounted for 80.75% of the changes in the abundances of ARGs. In conclusion, 15% Woody peat is beneficial to decrease the bioavailable Cu content and weaken horizontal gene transfer for controlling the spread of ARGs during composting.202134534940
8052150.8968Removal of chloramphenicol and resistance gene changes in electric-integrated vertical flow constructed wetlands. The performance of an electric-integrated vertical flow constructed wetland (E-VFCW) for chloramphenicol (CAP) removal, changes in microbial community structure, and the fate of antibiotic resistance genes (ARGs) were evaluated. CAP removal in the E-VFCW system was 92.73% ± 0.78% (planted) and 90.80% ± 0.61% (unplanted), both were higher than the control system which was 68.17% ± 1.27%. The contribution of anaerobic cathodic chambers in CAP removal was higher than the aerobic anodic chambers. Plant physiochemical indicators in the reactor revealed electrical stimulation increased oxidase activity. Electrical stimulation enhanced the enrichment of ARGs in the electrode layer of the E-VFCW system (except floR). Plant ARGs and intI1 levels were higher in the E-VFCW than in the control system, suggesting electrical stimulation induces plants to absorb ARGs, reducing ARGs in the wetland. The distribution of intI1 and sul1 genes in plants suggests that horizontal transfer may be the main mechanism dispersing ARGs in plants. High throughput sequencing analysis revealed electrical stimulation selectively enriched CAP degrading functional bacteria (Geobacter and Trichlorobacter). Quantitative correlation analysis between bacterial communities and ARGs confirmed the abundance of ARGs relates to the distribution of potential hosts and mobile genetic elements (intI1). E-VFCW is effective in treating antibiotic wastewater, however ARGs potentially accumulate.202337196621
3546160.8967Mitigation of tetracycline resistance genes in silage through targeted lactic acid bacteria inoculation. The dissemination of antibiotic resistance genes (ARGs) in silage ecosystems poses a critical challenge to ecological stability and public health security. This investigation focuses on tetracycline resistance genes (TRGs), the most prevalent subtype of ARGs in silage, employing a targeted selection strategy for lactic acid bacteria (LAB) inoculants. From 226 isolated LAB strains, four candidates (LP1-3: Lactiplantibacillus plantarum; LC1: Lacticaseibacillus paracasei) demonstrating superior growth kinetics (OD(600) > 1.6 within 24 h) and rapid acidification capacity (pH < 3.9 within 24 h) were selected. Strains LP3 and LC1 exhibited minimal intrinsic TRGs content. These four strains reduced (p < 0.001) pH, ammonia-N concentration, and coliform bacterial counts of stylo silage. Metagenomic analysis revealed that strains LP1-3 promoted Lactiplantibacillus dominance (0.709-0.975 vs. 0.379-0.509 in the control), while LC1 enhanced Lacticaseibacillus abundance (0.449-0.612 vs. 0.002-0.013 in the control). Ensiling process downregulated 367 and upregulated 227 ARGs. Inoculation with the four LAB strains further enhanced the suppression of ARGs. Among the top 30 TRGs, 22 were reduced by strains LP1-3 and 20 by LC1. Quantitative PCR results showed that strains LP1-3 decreased (p < 0.05) the contents of tetA and tetG during 30 days fermentation. Among the TRGs increased, tetA(60), tetB(58), tet(T) were positively correlated with Lactiplantibacillus spp., tetA(58), tetB(60), tetA(46), tetB(46), tet(43) were significantly correlated with Lacticaseibacillus spp. (R > 0.4, p < 0.001). In conclusion, the fermentation process induced substantial ARGs profile modifications, LAB-mediated microbiome engineering enables TRGs suppression, providing a scientific foundation for precision silage management strategies targeting antimicrobial resistance mitigation.202541038354
8055170.8967Effects of nano-zerovalent iron on antibiotic resistance genes during the anaerobic digestion of cattle manure. This study investigated the effects of adding nano-zerovalent iron (nZVI) at three concentrations (0, 80, and 160 mg/L) on the methane yield and the fate of antibiotic resistance genes (ARGs) during the anaerobic digestion (AD) of cattle manure. The addition of nZVI effectively enhanced the methane yield, where it significantly increased by 6.56% with 80 mg/L nZVI and by 6.43% with 160 mg/L nZVI. The reductions in the abundances of ARGs and Tn916/1545 were accelerated by adding 160 mg/L nZVI after AD. Microbial community analysis showed that nZVI mainly increased the abundances of bacteria with roles in hydrolysis and acidogenesis, whereas it reduced the abundance of Acinetobacter. Redundancy analysis indicated that the changes in mobile genetic elements made the greatest contribution to the fate of ARGs. The results suggest that 160 mg/L nZVI is a suitable additive for reducing the risks due to ARGs in AD.201931247529
8054180.8967Effects of nanoscale zero-valent iron on the performance and the fate of antibiotic resistance genes during thermophilic and mesophilic anaerobic digestion of food waste. The effects of nanoscale zero-valent iron (nZVI) on the performance of food waste anaerobic digestion and the fate of antibiotic resistance genes (ARGs) were investigated in thermophilic (TR) and mesophilic (MR) reactors. Results showed that nZVI enhanced biogas production and facilitated ARGs reduction. The maximum CH(4) production was 212.00 ± 4.77 ml/gVS with 5 g/L of nZVI in MR. The highest ARGs removal ratio was 86.64 ± 0.72% obtained in TR at nZVI of 2 g/L. nZVI corrosion products and their contribution on AD performance were analyzed. The abundance of tetracycline genes reduced significantly in nZVI amended digesters. Firmicutes, Chloroflexi, Proteobacteria and Spirochaetes showed significant positive correlations with various ARGs (p < 0.05) in MR and TR. Redundancy analysis indicated that microbial community was the main factor that influenced the fate of ARGs. nZVI changed microbial communities, with decreasing the abundance bacteria belonging to Firmicutes and resulting in the reduction of ARGs.201931505392
8495190.8966Effects of voltage and tetracycline on horizontal transfer of ARGs in microbial electrolysis cells. The abuse of antibiotics leads to the production of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs). Microbial electrolysis cells (MECs) have been widely applicated in the field of degrading antibiotics. ARGs were increased via horizontal transfer in single and two-chamber MECs. As one of the critical parameters in MECs, voltage has a particular impact on the ARGs transfer via horizontal transfer. However, there have been few studies of ARGs transfer under the exposure of antibiotics and voltage in MECs. In this study, five concentrations of tetracycline (0, 1, 5, 10, 20 mg/L) were selected to explore the conjugative transfer frequency of plasmid-encoded the ARGs from the donor (E. coli RP4) to receptor (E. coli HB101) in MECs, two voltages (1.5 and 2.0 V) were used to explore the conjugative transfer frequency of ARGs in MECs, then, the transfer of ARGs in MECs under the co-effect of tetracycline and voltage was explored. The results showed that the conjugative transfer frequency of ARGs was significantly increased with the increase of tetracycline concentration and voltage, respectively (p < 0.05). Under the pressure of tetracycline and voltage, the conjugative transfer frequency of ARGs is significantly enhanced with the co-effect of tetracycline and voltage (p < 0.05). The oxidative response induced by electrical stimulation promotes the overproduction of reactive oxygen species and the enhancement of cell membrane permeability of donor and recipient bacteria in MECs. These findings provide insights for studying the spread of ARGs in MECs.202435980276