KORB - Word Related Documents




#
Rank
Similarity
Title + Abs.
Year
PMID
012345
811000.9725Removal of chlortetracycline and antibiotic resistance genes in soil by earthworms (epigeic Eisenia fetida and endogeic Metaphire guillelmi). The impacts of two ecological earthworms on the removal of chlortetracycline (CTC, 0.5 and 15 mg kg(-1)) and antibiotic resistance genes (ARGs) in soil were explored through the soil column experiments. The findings showed that earthworm could significantly accelerate the degradation of CTC and its metabolites (ECTC) in soil (P < 0.05), with epigeic Eisenia fetida promoting degradation rapidly and endogeic Metaphire guillelmi exhibiting a slightly better elimination effect. Earthworms alleviated the abundances of tetR, tetD, tetPB, tetG, tetA, sul1, TnpA, ttgB and intI1 in soil, with the total relative abundances of ARGs decreasing by 35.0-44.2% in earthworm treatments at the 28th day of cultivation. High throughput sequencing results displayed that the structure of soil bacteria community was modified apparently with earthworm added, and some possible CTC degraders, Aeromonas, Flavobacterium and Luteolibacter, were promoted by two kinds of earthworms. Redundancy analysis demonstrated that the reduction of CTC residues, Actinobacteria, Acidobacteria and Gemmatimonadetes owing to earthworm stimulation was responsible for the removal of ARGs and intI1 in soil. Additionally, intI1 declined obviously in earthworm treatments, which could weaken the risk of horizontal transmission of ARGs. Therefore, earthworm could restore the CTC-contaminated soil via enhancing the removal of CTC, its metabolites and ARGs.202133798888
794010.9724Microplastics affect the ammonia oxidation performance of aerobic granular sludge and enrich the intracellular and extracellular antibiotic resistance genes. Microplastics (MPs) and antibiotic resistance genes (ARGs), as emerging pollutants, are frequently detected in wastewater treatment plants, and their threats to the environment have received extensive attentions. However, the effects of MPs on the nitrification of aerobic granular sludge (AGS) and the spread patterns of intracellular and extracellular ARGs (iARGs and eARGs) in AGS were still unknown. In this study, the responses of AGS to the exposure of 1, 10 and 100 mg/L of typical MPs (polyvinyl chloride (PVC), polyamide (PA), polystyrene (PS) and polyethylene (PE)) and tetracycline were focused on in 3 L nitrifying sequencing batch reactors. 10 mg/L MPs decreased the nitrification function, but nitrification could recover. Furthermore, MPs inhibited ammonia-oxidizing bacteria and enriched nitrite-oxidizing bacteria, leading partial nitrification to losing stability. PVC, PA and PS stimulated the secretion of extracellular polymeric substances and reactive oxygen species. PE had less negative effect on AGS than PVC, PA and PS. The abundances of iARGs and eARGs (tetW, tetE and intI1) increased significantly and the intracellular and extracellular microbial communities obviously shifted in AGS system under MPs stress. Potential pathogenic bacteria might be the common hosts of iARGs and eARGs in AGS system and were enriched in AGS and MPs biofilms.202133387747
787220.9723Quaternary ammonium compounds promoted anoxic sludge granulation and altered propagation risk of intracellular and extracellular antibiotic resistance genes. Surfactants could influence sludge morphology and disinfectants were linked to antibiotic resistance genes (ARGs). Thus, the response of activated sludge and ARGs to long-term quaternary ammonium compounds (QACs) exposure required further investigation, which is a popular surfactant and disinfectant. Here, three sequencing batch reactors were fed with 5 mg/L most frequently detected QACs (dodecyl trimethyl ammonium chloride (ATMAC C12), dodecyl benzyl dimethyl ammonium chloride (BAC C12) and didodecyl dimethyl ammonium chloride (DADMAC C12)) for 180 d. The long-term inhibitory effect on denitrification ranked: DADMAC C12 > BAC C12 > ATMAC C12. Besides, obvious granular sludge promoted by the increase of α-Helix/(β-Sheet + Random coil) appeared in DADMAC C12 system. Moreover, intracellular ARGs increased when denitrification systems encountered QACs acutely but decreased in systems chronically exposed to QACs. Although replication and repair metabolism in ATMAC C12 system was higher, ATMAC C12 significantly promoted proliferation of extracellular ARGs. It was noteworthy that the propagation risk of extracellular ARGs in sludge increased significantly during sludge granulation process, and intracellular sul2 genes in sludge and water both increased with the granular diameter in DADMAC C12 system. The universal utilization of QACs may enhance antibiotic resistance of bacteria in wastewater treatment plants, deserving more attention.202336444811
787130.9721Effects 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
792640.9716Microplastics Exacerbated Conjugative Transfer of Antibiotic Resistance Genes during Ultraviolet Disinfection: Highlighting Difference between Conventional and Biodegradable Ones. Microplastics (MPs) have been confirmed as a hotspot for antibiotic resistance genes (ARGs) in wastewater. However, the impact of MPs on the transfer of ARGs in wastewater treatment remains unclear. This study investigated the roles and mechanisms of conventional (polystyrene, PS) and biodegradable (polylactic acid, PLA) MPs in the conjugative transfer of ARGs during ultraviolet disinfection. The results showed that MPs significantly facilitated the conjugative transfer of ARGs compared with individual ultraviolet disinfection, and PSMPs exhibited higher facilitation than PLAMPs. The facilitation effects were attributed to light shielding and the production of reactive oxygen species (ROS) and nanoplastics from ultraviolet irradiation of MPs. The light shielding of MPs protected the bacteria and ARGs from ultraviolet inactivation. More importantly, ROS and nanoplastics generated from irradiated MPs induced intracellular oxidative stress on bacteria and further increased the cell membrane permeability and intercellular contact, ultimately enhancing the ARG exchange. The greater fragmentation of PSMPs than PLAMPs resulted in a higher intracellular oxidative stress and a stronger enhancement. This study highlights the concerns of conventional and biodegradable MPs associated with the transfer of ARGs during wastewater treatment, which provides new insights into the combined risks of MPs and ARGs in the environment.202539723446
811750.9714Composting of oxytetracycline fermentation residue in combination with hydrothermal pretreatment for reducing antibiotic resistance genes enrichment. Hydrothermal pretreatment can efficiently remove the residual antibiotics in oxytetracycline fermentation residue (OFR), but its effect on antibiotic resistance genes (ARGs) during composting remains unclear. This study compared the shifts in bacterial community and evolutions in ARGs and integrons during different composting processes of OFRs with and without hydrothermal pretreatment. The results demonstrated that hydrothermal pretreatment increased the bacterial alpha diversity at the initial phase, and increased the relative abundances of Proteobacteria and Actinobacteria but decreased that of Bacteroidetes at the final phase by inactivating mycelia and removing residual oxytetracycline. Composting process inevitably elevated the abundance and relative abundance of ARGs. However, the increase in ARGs was significantly reduced by hydrothermal pretreatment, because the removal of oxytetracycline decreased their potential host bacteria and inhibited their horizontal gene transfer. The results demonstrated that hydrothermal pretreatment is an efficient strategy to reduce the enrichment of ARGs during the OFR composting.202033099099
793560.9712Removal of antibiotic resistance genes by Cl(2)-UV process: Direct UV damage outweighs free radicals in effectiveness. Antibiotic resistance genes (ARGs) pose significant environmental health problems and have become a major global concern. This study investigated the efficacy and mechanism of the Cl(2)-UV process (chlorine followed by UV irradiation) for removing ARGs in various forms. The Cl(2)-UV process caused irreversible damage to nearly all ARB at typical disinfectant dosages. In solutions containing only extracellular ARGs (eARGs), the Cl₂-UV process achieved over 99.0 % degradation of eARGs. When both eARGs and intracellular ARGs (iARGs) were present, the process reached a 97.2 % removal rate for iARGs. While the abundance of eARGs initially increased due to the release of iARGs from lysed cells during pre-chlorination, subsequent UV irradiation rapidly degraded the released eARGs, restoring their abundance to near-initial levels by the end of the Cl₂-UV process. Analysis of the roles in degrading eARGs and iARGs during the Cl(2)-UV process revealed that UV, rather than free radicals, was the dominant factor causing ARG damage. Pre-chlorination enhanced direct UV damage to eARGs and iARGs by altering plasmid conformation and promoting efficient damage to high UV-absorbing cellular components. Furthermore, no further natural transformation of residual ARGs occurred following the Cl(2)-UV treatment. This study demonstrated strong evidence for the effectiveness of the Cl(2)-UV process in controlling antibiotic resistance.202540048777
812370.9712The effect of bulk-biochar and nano-biochar amendment on the removal of antibiotic resistance genes in microplastic contaminated soil. Biochar amendment has significant benefits in removing antibiotic resistance genes (ARGs) in the soil. Nevertheless, there is little information on ARGs removal in microplastic contaminated soil. Herein, a 42-day soil microcosm experiment were carried out to study how two coconut shell biochars (bulk- and nano-size) eliminate soil ARGs with/without microplastic presence. The results showed that microplastic increased significantly the numbers and abundances of ARGs in soil at 14d of cultivation. And, two biochars amendment effectively inhibited soil ARGs spread whether or not microplastic was present, especially for nano-biochar which had more effective removal compared to bulk-biochar. However, microplastic weakened soil ARGs removal after applying same biochar. Two biochars removed ARGs through decreasing horizontal gene transfer (HGT) of ARGs, potential host-bacteria abundances, some bacteria crowding the eco-niche of hosts and promoting soil properties. The adverse effect of microplastic on ARGs removal was mainly caused by weakening mobile genetic elements (MGEs) removal, and by changing soil properties. Structural equation modeling (SEM) analysis indicated that biochar's effect on ARGs profile was changed by its size and microplastic presence through altering MGEs abundances. These results highlight that biochar amendment is still an effective method for ARGs removal in microplastic contaminated soil.202437907163
811180.9711Effect of alkaline-thermal pretreatment on biodegradable plastics degradation and dissemination of antibiotic resistance genes in co-compost system. Biodegradable plastics (BDPs) are an eco-friendly alternative to traditional plastics in organic waste, but their microbial degradation and impact on antibiotic resistance genes (ARGs) transmission during co-composting remain poorly understood. This study examines how alkaline-thermal pretreatment enhances BDPs degradation and influences the fate of ARGs and mobile genetic elements (MGEs) in co-composting. Pretreatment with 0.1 mol/L NaOH at 100℃ for 40 minutes increased the surface roughness and hydrophilicity of BDPs while reducing their molecular weight and thermal stability. Incorporating pretreated BDPs film (8 g/kg-TS) into the compost reduced the molecular weight of the BDPs by 59.70 % during the maturation stage, facilitating compost heating and prolonging the thermophilic stage. However, incomplete degradation of BDPs releases numerous smaller-sized microplastics, which can act as carriers for microorganisms, facilitating the dissemination of ARGs across environments and posing significant ecological and public health risks. Metagenomic analysis revealed that pretreatment enriched plastic-degrading bacteria, such as Thermobifida fusca, on BDPs surfaces and accelerated microbial plastic degradation during the thermophilic stage, but also increased ARGs abundance. Although pretreatment significantly reduced MGEs abundance (tnpA, IS19), the risk of ARGs dissemination remained. Three plastic-degrading bacteria (Pigmentiphaga sp002188465, Bacillus clausii, and Bacillus altitudinis) were identified as ARGs hosts, underscoring the need to address the risk of horizontal gene transfer of ARGs associated with pretreatment in organic waste management.202539970645
792590.9710Effects comparison between the secondary nanoplastics released from biodegradable and conventional plastics on the transfer of antibiotic resistance genes between bacteria. Antibiotic resistance genes (ARGs) have caused widespread concern because of their potential harm to environmental safety and human health. As substitutes for conventional plastics, the toxic effects of short-term degradation products of biodegradable plastics (polylactic acid (PLA) and polyhydroxyalkanoates (PHA)) on bacteria and their impact on ARGs transfer were the focus of this study. After 60 days of degradation, more secondary nanoplastics were released from the biodegradable plastics PLA and PHA than that from the conventional plastics polystyrene (PS). All kinds of nanoplastics, no matter released from biodegradable plastics or conventional plastics, had no significant toxicity to bacteria. Nanoplastic particles from biodegradable plastics could significantly increase the transfer efficiency of ARGs. Although the amount of secondary nanoplastics produced by PHA microplastics was much higher than that of PLA, the transfer frequency after exposure to PLA was much higher, which may be due to the agglomeration of PHA nanoplastics caused by plastic instability in solution. After exposure to the 60 d PLA nanoplastics, the transfer frequency was the highest, which was approximately 28 times higher than that of control. The biodegradable nanoplastics significantly enhanced the expression of the outer membrane pore protein genes ompA and ompC, which could increase cell membrane permeability. The expression levels of trfAp and trbBp were increased by repressed major global regulatory genes korA, korB, and trbA, which eventually led to an increase in conjugative transfer frequency. This study provides important insights into the evaluation of the environmental and health risks caused by secondary nanoplastics released from biodegradable plastics.202336414161
7897100.9710Enhanced 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
8112110.9710Fate of antibiotic resistance bacteria and genes during enhanced anaerobic digestion of sewage sludge by microwave pretreatment. The fate of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) were investigated during the sludge anaerobic digestion (AD) with microwave-acid (MW-H), microwave (MW) and microwave-H2O2-alkaline (MW-H2O2) pretreatments. Results showed that combined MW pretreatment especially for the MW-H pretreatment could efficiently reduce the ARB concentration, and most ARG concentrations tended to attenuate during the pretreatment. The subsequent AD showed evident removal of the ARB, but most ARGs were enriched after AD. Only the concentration of tetX kept continuous declination during the whole sludge treatment. The total ARGs concentration showed significant correlation with 16S rRNA during the pretreatment and AD. Compared with unpretreated sludge, the AD of MW and MW-H2O2 pretreated sludge presented slightly better ARB and ARGs reduction efficiency.201626970692
7898120.9709Effects of graphite and Mn ore media on electro-active bacteria enrichment and fate of antibiotic and corresponding resistance gene in up flow microbial fuel cell constructed wetland. This study assessed the influence of substrate type on pollutants removal, antibiotic resistance gene (ARG) fate and bacterial community evolution in up-flow microbial fuel cell constructed wetlands (UCW-MFC) with graphite and Mn ore electrode substrates. Better COD removal and higher bacterial community diversity and electricity generation performance were achieved in Mn ore constructed UCW-MFC (Mn). However, the lower concentration of sulfadiazine (SDZ) and the total abundances of ARGs were obtained in the effluent in the graphite constructed UCW-MFC (s), which may be related to higher graphite adsorption and filter capacity. Notably, both reactors can remove more than 97.8% of ciprofloxacin. In addition, significant negative correlations were observed between SDZ, COD concentration, ARG abundances and bacterial a-diversity indices. The LEfse analysis revealed significantly different bacterial communities due to the substrate differences in the two reactors, and Geobacter, a typical model electro-active bacteria (EAB), was greatly enriched on the anode of UCW-MFC (Mn). In contrast, the relative abundance of methanogens (Methanosaeta) was inhibited. PICRUSt analysis results further demonstrated that the abundance of extracellular electron transfer related functional genes was increased, but the methanogen function genes and multiple antibiotic resistance genes in UCW-MFC (Mn) anode were reduced. Redundancy analyses indicated that substrate type, antibiotic accumulation and bacterial community were the main factors affecting ARGs. Moreover, the potential ARG hosts and the co-occurrence of ARGs and intI1 were revealed by network analysis.201931442759
7878130.9708Horizontal transfer of the multidrug resistance plasmid RP4 inhibits ammonia nitrogen removal dominated by ammonia-oxidizing bacteria. Antibiotic resistance genes (ARGs) have become an important public health concern. Particularly, although several ARGs have been identified in wastewater treatment plants (WWTPs), very few studies have characterized their impacts on reactor performance. Therefore, our study sought to investigate the effect of a representative conjugative transfer plasmid (RP4) encoding multidrug resistance genes on ammonia oxidation. To achieve this, we established sequencing batch reactors (SBRs) and a conjugation model with E. coli donor strains carrying the RP4 plasmid and a typical ammonia-oxidating (AOB) bacterial strain (Nitrosomonas europaea ATCC 25978) as a recipient to investigate the effect of conjugative transfer of plasmid RP4 on AOB. Our findings demonstrated that the RP4 plasmid carried by the donor strains could be transferred to AOB in the SBR and to Nitrosomonas europaea ATCC 25978. In SBR treated with donor strains carrying the RP4 plasmid, ammonia removal efficiency continuously decreased to 71%. Once the RP4 plasmid entered N. europaea ATCC 25978 in the conjugation model, ammonia removal was significantly inhibited and nitrite generation was decreased. Furthermore, the expression of several functional genes related to ammonia oxidation in AOB was suppressed following the transfer of the RP4 plasmid, including amoA, amoC, hao, nirK, and norB. In contrast, the cytL gene encoding cytochrome P460 was upregulated. These results demonstrated the ecological risk of ARGs in WWTPs, and therefore measures must be taken to avoid their transfer.202235427829
7904140.9707Effect of the coexposure of sulfadiazine, ciprofloxacin and zinc on the fate of antibiotic resistance genes, bacterial communities and functions in three-dimensional biofilm-electrode reactors. Three-dimensional biofilm electrode reactors (3D-BERs) with high treatment efficiency were constructed to treat wastewater containing sulfadiazine (SDZ) and ciprofloxacin (CIP) coexposure with Zinc (Zn). The results showed that coexposure to target antibiotics and Zn increased the absolute and relative abundances of target antibiotic resistance genes (ARGs). Additionally, the target ARG abundances were higher on cathode of 3D-BER compared with ordinary anaerobic reactor while the abundances of total ARGs were decreased in the effluent. Meanwhile, redundancy analysis results revealed that the composition of bacteria carrying ARGs was greatly influenced in the cathode by the accumulation of Zn and antibiotic, which dominated the changes of ARG abundances. Additionally, ARGs with their host bacteria revealed by network analysis were partially deposited on electrode substrates when being removed from wastewater. Thus, 3D-BER exhibits capability of simultaneously eliminating antibiotic and Zn, and greatly reduces the risks of ARGs spread.202031677404
7858150.9706Photocatalytic Reactive Ultrafiltration Membrane for Removal of Antibiotic Resistant Bacteria and Antibiotic Resistance Genes from Wastewater Effluent. Biological wastewater treatment is not effective in removal of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs). In this study, we fabricated a photocatalytic reactive membrane by functionalizing polyvinylidene fluoride (PVDF) ultrafiltration (UF) membrane with titanium oxide (TiO(2)) nanoparticles for the removal of ARB and ARGs from a secondary wastewater effluent. The TiO(2)-modified PVDF membrane provided complete retention of ARB and effective photocatalytic degradation of ARGs and integrons. Specifically, the total removal efficiency of ARGs (i.e., plasmid-mediated floR, sul1, and sul2) with TiO(2)-modified PVDF membrane reached ∼98% after exposure to UV irradiation. Photocatalytic degradation of ARGs located in the genome was found to be more efficient than those located in plasmid. Excellent removal of integrons (i.e., intI1, intI2, and intI3) after UV treatment indicated that the horizontal transfer potential of ARGs was effectively controlled by the TiO(2) photocatalytic reaction. We also evaluated the antifouling properties of the TiO(2)-UF membrane to demonstrate its potential application in wastewater treatment.201829984583
8125160.9705The removal performances and evaluation of heavy metals, antibiotics, and resistomes driven by peroxydisulfate amendment during composting. This study aimed to explore the effect of peroxydisulfate on the removal of heavy metals, antibiotics, heavy metal resistance genes (HMRGs), and antibiotic resistance genes (ARGs) during composting. The results showed that peroxydisulfate achieved the passivation of Fe, Mn, Zn, and Cu by promoting their speciation variations, thus reducing their bioavailability. And the residual antibiotics were better degraded by peroxydisulfate. In addition, metagenomics analysis indicated that the relative abundance of most HMRGs, ARGs, and MGEs was more effectively down-regulated by peroxydisulfate. Network analysis confirmed Thermobifida and Streptomyces were dominant potential host bacteria of HMRGs and ARGs, whose relative abundance was also effectively down-regulated by peroxydisulfate. Finally, mantel test showed the significant effect of the evolution of microbial communities and strong oxidation of peroxydisulfate on the removal of pollutants. These results suggested that heavy metals, antibiotics, HMRGs, and ARGs shared a joint fate of being removed driven by peroxydisulfate during composting.202337307729
8493170.9704Effects and mechanisms of plant growth regulators on horizontal transfer of antibiotic resistance genes through plasmid-mediated conjugation. A vast number of bacteria occur in both soil and plants, with some of them harboring antibiotic resistance genes (ARGs). When bacteria congregate on the interface of soil particles or on plant root surfaces, these ARGs can be transferred between bacteria via conjugation, leading to the formation of antibiotic-resistant pathogens that threaten human health. Plant growth regulators (PGRs) are widely used in agricultural production, promoting plant growth and increasing crop yields. However, until now, little information has been known about the effects of PGRs on the horizontal gene transfer (HGT) of ARGs. In this study, with Escherichia coli DH5α (carrying RP4 plasmid with Tet(R), Amp(R), Kan(R)) as the donor and E. coli HB101 as the recipient, a series of diparental conjugation experiments were conducted to investigate the effects of indoleacetic acid (IAA), ethel (ETH) and gibberellin (GA(3)) on HGT of ARGs via plasmid-mediated conjugation. Furthermore, the mechanisms involved were also clarified. The results showed that all three PGRs affected the ARG transfer frequency by inducing the intracellular reactive oxygen species (ROS) formation, changing the cell membrane permeability, and regulating the gene transcription of traA, traL, trfAp, trbBp, kilA, and korA in plasmid RP4. In detail, 50-100 mg⋅L(-1) IAA, 20-50 mg⋅L(-1) ETH and 1500-2500 mg⋅L(-1) GA(3) all significantly promoted the ARG conjugation. This study indicated that widespread use of PGRs in agricultural production could affect the HGT of ARGs via plasmid-mediated conjugation, and the application of reasonable concentrations of PGRs could reduce the ARG transmission in both soil environments and plants.202336720410
7937180.9704Effects of oxytetracycline on variation in intracellular and extracellular antibiotic resistance genes during swine manure composting. This research aimed to investigate the alterations in extracellular (eARGs) and intracellular (iARGs) antibiotic resistance genes in response to oxytetracycline (OTC), and unravel the dissemination mechanism of ARGs during composting. The findings revealed both low (L-OTC) and high contents (H-OTC) of OTC significantly enhanced absolute abundance (AA) of iARGs (p < 0.05), compared to CK (no OTC). Composting proved to be a proficient strategy for removing eARGs, while AA of eARGs was significantly enhanced in H-OTC (p < 0.05). OTC resulted in an increase in AA of mobile genetic elements (MGEs), ATP levels, antioxidant and DNA repair enzymes in bacteria in compost product. Structural equation model further demonstrated that OTC promoted bacterial DNA repair and antioxidant enzyme activities, altered bacterial community and enhanced MGEs abundance, thereby facilitating iARGs dissemination. This study highlights OTC can increase eARGs and iARGs abundance, underscoring the need for appropriate countermeasures to mitigate potential hazards.202438036151
8491190.9704Hormesis-like effects of black phosphorus nanosheets on the spread of multiple antibiotic resistance genes. The production scalability and increasing demand for black phosphorus nanosheets (BPNSs) inevitably lead to environmental leakage. Although BPNSs' ecotoxicological effects have been demonstrated, their indirect health risks, such as inducing increased resistance in pathogenic bacteria, are often overlooked. This study explores the influence of BPNSs on the horizontal gene transfer of antibiotic resistance genes (ARGs) facilitated by the RP4 plasmid, which carries multiple resistance genes. The results indicated that BPNSs exhibited concentration-dependent hormesis-like effects on bacterial conjugation gene transfer. Specifically, at sub-inhibitory concentrations (0.0001-1 mg/L), BPNSs promoted both intra- and intergeneric conjugative transfer, demonstrating an initial increase followed by a decline, with transfer rates rising by 1.5-3.1-fold and 1.5-3.3-fold, respectively. BPNSs were found to induce reactive oxygen species (ROS) production, increase malondialdehyde levels, and trigger the SOS response, enhancing plasmid uptake. Additionally, BPNSs increased membrane permeability by forming pores and upregulating outer membrane porins (OMPs) genes. At higher BPNSs concentrations (0.1-1 mg/L), conjugative frequency was inhibited due to the disruption of the cellular antioxidant system and changes in the adsorption process. These findings underscore the influence of BPNSs on the conjugative transfer of ARGs, complementing current knowledge of the biotoxicity and potential ecological risks associated with BPNSs.202539827804