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795000.9936Fate and removal of fluoroquinolone antibiotics in mesocosmic wetlands: Impact on wetland performance, resistance genes and microbial communities. The fate of fluoroquinolone antibiotics norfloxacin and ofloxacin were investigated in mesocosmic wetlands, along with their effects on nutrients removal, antibiotic resistance genes (ARGs) and epiphytic microbial communities on Hydrilla verticillate using bionic plants as control groups. Approximately 99% of norfloxacin and ofloxacin were removed from overlaying water, and H. verticillate inhibited fluoroquinolones accumulation in surface sediments compared to bionic plants. Partial least squares path modeling showed that antibiotics significantly inhibited the nutrient removal capacity (0.55) but had no direct effect on plant physiology. Ofloxacin impaired wetland performance more strongly than norfloxacin and more impacted the primary microbial phyla, whereas substrates played the most decisive role on microbial diversities. High antibiotics concentration shifted the most dominant phyla from Proteobacteria to Bacteroidetes and inhibited the Xenobiotics biodegradation function, contributing to the aggravation in wetland performance. Dechloromonas and Pseudomonas were regarded as the key microorganisms for antibiotics degradation. Co-occurrence network analysis excavated that microorganisms degrade antibiotics mainly through co-metabolism, and more complexity and facilitation/reciprocity between microbes attached to submerged plants compared to bionic plants. Furthermore, environmental factors influenced ARGs mainly by altering the community dynamics of differential bacteria. This study offers new insights into antibiotic removal and regulation of ARGs accumulation in wetlands with submerged macrophyte.202438569335
794710.9936Molecular insights into linkages among free-floating macrophyte-derived organic matter, the fate of antibiotic residues, and antibiotic resistance genes. Macrophyte rhizospheric dissolved organic matter (ROM) served as widespread abiotic components in aquatic ecosystems, and its effects on antibiotic residues and antibiotic resistance genes (ARGs) could not be ignored. However, specific influencing mechanisms for ROM on the fate of antibiotic residues and expression of ARGs still remained unclear. Herein, laboratory hydroponic experiments for water lettuce (Pistia stratiotes) were carried out to explore mutual interactions among ROM, sulfamethoxazole (SMX), bacterial community, and ARGs expression. Results showed ROM directly affect SMX concentrations through the binding process, while CO and N-H groups were main binding sites for ROM. Dynamic changes of ROM molecular composition diversified the DOM pool due to microbe-mediated oxidoreduction, with enrichment of heteroatoms (N, S, P) and decreased aromaticity. Microbial community analysis showed SMX pressure significantly stimulated the succession of bacterial structure in both bulk water and rhizospheric biofilms. Furthermore, network analysis further confirmed ROM bio-labile compositions as energy sources and electron shuttles directly influenced microbial structure, thereby facilitating proliferation of antibiotic resistant bacteria (Methylotenera, Sphingobium, Az spirillum) and ARGs (sul1, sul2, intl1). This investigation will provide scientific supports for the control of antibiotic residues and corresponding ARGs in aquatic ecosystems.202438653136
864420.9935Biotic and abiotic drivers of soil carbon, nitrogen and phosphorus and metal dynamic changes during spontaneous restoration of Pb-Zn mining wastelands. The biotic and abiotic mechanisms that drive important biogeochemical processes (carbon, nitrogen, phosphorus and metals dynamics) in metal mine revegetation remains elusive. Metagenomic sequencing was used to explored vegetation, soil properties, microbial communities, functional genes and their impacts on soil processes during vegetation restoration in a typical Pb-Zn mine. The results showed a clear niche differentiation between bacteria, fungi and archaea. Compared to bacteria and fungi, the archaea richness were more tightly coupled with natural restoration changes. The relative abundances of CAZyme-related, denitrification-related and metal resistance genes reduced, while nitrification, urease, inorganic phosphorus solubilisation, phosphorus transport, and phosphorus regulation -related genes increased. Redundancy analysis, hierarchical partitioning analysis, relative-importance analysis and partial least squares path modelling, indicated that archaea diversity, primarily influenced by available lead, directly impacts carbon dynamics. Functional genes, significantly affected by available cadmium, directly alter nitrogen dynamics. Additionally, pH affects phosphorus dynamics through changes in bacterial diversity, while metal dynamics are directly influenced by vegetation. These insights elucidate natural restoration mechanisms in mine and highlight the importance of archaea in soil processes.202540054196
693430.9933Impact of protist predation on bacterial community traits in river sediments. Sediment-associated microbial communities are pivotal in driving biogeochemical processes and serve as key indicators of ecosystem health and function. However, the ecological impact of protist predation on these microbial communities remains poorly understood. Here, sediment microcosms were established with varying concentrations of indigenous protists. Results revealed that protist predation exerted strong and differential effects on the bacterial community composition, functional capabilities, and antibiotic resistance profiles. Higher levels of protist predation pressure increased bacterial alpha diversity and relative abundance of genera associated with carbon and nitrogen cycling, such as Fusibacter, Methyloversatilis, Azospirillum, and Holophaga. KEGG analysis indicated that protist predation stimulated microbial processes related to the carbon, nitrogen, and sulfur cycles. Notably, the relative abundance and associated health risks of antibiotic resistance genes (ARGs), virulence factor genes (VFGs), and mobile genetic elements (MGEs) were affected by predation pressure. Medium protist predation pressure increased the relative abundance and potential risks associated with ARGs, whereas high protist concentrations led to a reduction in both, likely due to a decrease in the relative abundance of ARG-hosting pathogenic bacteria such as Pseudomonas, Acinetobacter, and Aeromonas. These findings provide comprehensive insights into the dynamics of bacterial communities under protist predation in river sediment ecosystems.202540885182
792740.9932Different microplastics distinctively enriched the antibiotic resistance genes in anaerobic sludge digestion through shifting specific hosts and promoting horizontal gene flow. Both microplastics (MPs) and antibiotic resistance genes (ARGs) are intensively detected in waste activated sludge (WAS). However, the distinctive impacts of different MPs on ARGs emergence, dissemination, and its potential mechanisms remain unclear. In this study, long-term semi-continuous digesters were performed to examine the profiles of ARGs and antibiotic-resistant bacteria (ARB) in response to two different typical MPs (polyethylene (PE) and polyvinyl chloride (PVC)) in anaerobic sludge digestion. Metagenomic results show that PE- and PVC-MPs increase ARGs abundance by 14.8% and 23.6% in digester, respectively. ARB are also enriched by PE- and PVC-MPs, Acinetobacter sp. and Salmonella sp. are the dominant ARB. Further exploration reveals that PVC-MPs stimulates the acquisition of ARGs by human pathogen bacteria (HPB) and functional microorganisms (FMs), but PE-MPs doesn't. Network analysis shows that more ARGs tend to co-occur with HBP and FMs after MPs exposure, and more importantly, new bacteria are observed to acquire ARGs possibly via horizontal gene flow (HGF) in MPs-stressed digester. The genes involved in the HGF process, including reactive oxygen species (ROS) production, cell membrane permeability, extracellular polymeric substances (EPS) secretion, and ATP synthesis, are also enhanced by MPs, thereby attributing to the promoted ARGs dissemination. These findings offer advanced insights into the distinctive contribution of MPs to fate, host, dissemination of ARGs in anaerobic sludge digestion.202336423550
864850.9931Host-specific assembly of phycosphere microbiome and enrichment of the associated antibiotic resistance genes: Integrating species of microalgae hosts, developmental stages and water contamination. Phytoplankton-bacteria interactions profoundly impact ecosystem function and biogeochemical cycling, while their substantial potential to carry and disseminate antibiotic resistance genes (ARGs) poses a significant threat to global One Health. However, the ecological paradigm behind the phycosphere assembly of microbiomes and the carrying antibiotic resistomes remains unclear. Our field investigation across various freshwater ecosystems revealed a substantial enrichment of bacteria and ARGs within microalgal niches. Taking account of the influence for species of microalgae hosts, their developmental stages and the stress of water pollution, we characterized the ecological processes governing phycosphere assembly of bacterial consortia and enrichment of the associated ARGs. By inoculating 6 axenic algal hosts with two distinct bacterial consortia from a natural river and the phycosphere of Scenedesmus acuminatus, we observed distinct phycosphere bacteria recruitment among different algal species, yet consistency within the same species. Notably, a convergent bacterial composition was established for the same algae species for two independent inoculations, demonstrating host specificity in phycosphere microbiome assembly. Host-specific signature was discernible as early as the algal lag phase and more pronounced as the algae developed, indicating species types of algae determined mutualism between the bacterial taxa and hosts. The bacteria community dominated the shaping of ARG profiles within the phycosphere and the host-specific phycosphere ARG enrichment was intensified with the algae development. The polluted water significantly stimulated host's directional selection on phycosphere bacterial consortia and increased the proliferation antibiotic resistome. These consortia manifested heightened beneficial functionality, enhancing microalgal adaptability to contamination stress.202540349825
693860.9930Assessment of the Effects of Biodegradable and Nonbiodegradable Microplastics Combined with Pesticides on the Soil Microbiota. Microplastics (MPs) and pesticides pose significant threats to the health of soil ecosystems. This study investigated the individual and combined effects of biodegradable polylactic acid (PLA) and nonbiodegradable polyethylene terephthalate (PET) microplastics alongside glyphosate and imidacloprid pesticides on soil microbial communities and antibiotic resistance genes (ARGs) via microcosm experiments. Compared with the control, PLA significantly increased microbial alpha diversity and enhanced microbial functions related to environmental information processing and metabolism. However, PLA also selectively enriched populations of beneficial and potentially pathogenic bacteria, whereas PET had comparatively weaker effects. Crucially, PLA exposure resulted in substantially higher total abundance and ecological risk levels of soil ARGs than did PET. Coexposure with pesticides further amplified these effects, with PLA demonstrating notable synergistic interactions with both glyphosate and imidacloprid. These findings challenge the conventional assumption that biodegradable MPs such as PLA are environmentally safer than nonbiodegradable MPs, thus highlighting their potential to induce more complex and potentially severe ecological risks under co-contamination scenarios with pesticides.202541175058
794070.9930Microplastics 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
794580.9930Effects of eutrophication on the horizontal transfer of antibiotic resistance genes in microalgal-bacterial symbiotic systems. Overloading of nutrients such as nitrogen causes eutrophication of freshwater bodies. The spread of antibiotic resistance genes (ARGs) poses a threat to ecosystems. However, studies on the enrichment and spread of ARGs from increased nitrogen loading in algal-bacterial symbiotic systems are limited. In this study, the transfer of extracellular kanamycin resistance (KR) genes from large (RP4) small (pEASY-T1) plasmids into the intracellular and extracellular DNA (iDNA, eDNA) of the inter-algal environment of Chlorella pyrenoidosa was investigated, along with the community structure of free-living (FL) and particle-attached (PA) bacteria under different nitrogen source concentrations (0-2.5 g/L KNO(3)). The results showed that KR gene abundance in the eDNA adsorbed on solid particles (D-eDNA) increased initially and then decreased with increasing nitrogen concentration, while the opposite was true for the rest of the free eDNA (E-eDNA). Medium nitrogen concentrations promoted the transfer of extracellular KR genes into the iDNA attached to algal microorganisms (A-iDNA), eDNA attached to algae (B-eDNA), and the iDNA of free microorganisms (C-iDNA); high nitrogen contributed to the transfer of KR genes into C-iDNA. The highest percentage of KR genes was found in B-eDNA with RP4 plasmid treatment (66.2%) and in C-iDNA with pEASY-T1 plasmid treatment (86.88%). In addition, dissolved oxygen (DO) significantly affected the bacterial PA and FL community compositions. Nephelometric turbidity units (NTU) reflected the abundance of ARGs in algae. Proteobacteria, Cyanobacteria, Bacteroidota, and Actinobacteriota were the main potential hosts of ARGs. These findings provide new insights into the distribution and dispersal of ARGs in the phytoplankton inter-algal environment.202438493856
792890.9929Insight into the responses of antibiotic resistance genes in microplastic biofilms to zinc oxide nanoparticles and zinc ions pressures in landfill leachate. Microplastic (MP) biofilms are hotspots of antibiotic resistance genes (ARGs) in landfill environment. MP biofilms in landfill leachate coexist with heavy metals and metallic nanoparticles (NPs) that considered to be the selective agents of ARGs. However, the effects of these selective pressures on ARGs in MP biofilms and their differences in MP-surrounding leachate have not been well understood. Herein, the changes of ARG abundances in MP biofilms and corresponding leachate under zinc oxide (ZnO) NPs and zinc ion (Zn(2+)) pressures were comparatively analyzed. The presence of ZnO NPs and Zn(2+) promoted the enrichment of ARGs in MP biofilms, and the enrichment was more pronounced in ZnO NPs groups. ZnO NPs and especially Zn(2+) mainly decreased the abundances of ARGs in leachate. The increase of integron abundances and reactive oxygen species production in MP biofilms implied the enhanced potential for horizontal transfer of ARGs under ZnO NPs and Zn(2+) pressures. Meanwhile, the co-occurrence pattern between ARGs and bacterial genera in MP biofilms with more diverse potential ARG hosts was more complex than in leachate, and the enrichment of ARG-hosting bacteria in MP biofilms under ZnO NPs and Zn(2+) pressures supported the enrichment of ARGs.202337480611
7926100.9929Microplastics 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
6937110.9929Differential responses of bacterial and archaeal communities to biodegradable and non-biodegradable microplastics in river. Microplastics are widespread environmental pollutants that pose risks to ecosystems, yet their effects on bacterial and archaeal communities in aquatic ecosystems remain understudied. In this study, we performed a 14-day microcosm experiment combined with metagenomic sequencing to compare bacterial and archaeal responses to a biodegradable microplastic (polylactic acid, PLA) and a non-biodegradable microplastic (polyvinyl chloride, PVC). Microplastics selectively enriched distinct microbial assemblages, with Pseudomonadota and Euryarchaeota identified as the dominant bacterial and archaeal phyla, accounting for 67.83 % and 15.95 %, respectively. Archaeal community in surrounding water were more sensitive to colonization time than bacterial community. Compared to the surrounding water, the plastisphere displayed simpler and more loosely connected microbial networks. Notably, co-occurrence networks of both bacteria and archaea in the PVC plastisphere were predominantly shaped by symbiotic interactions. Both bacteria and archaea carried diverse antibiotic resistance genes (ARGs), but PLS-PM indicated that bacteria were the primary drivers of ARG dissemination (path coefficient = 0.952). While the PVC plastisphere showed higher ARG abundance than the PLA plastisphere, elevated intI1 expression in the PLA plastisphere suggests a potentially greater risk of ARG dissemination associated with PLA microplastics. These findings reveal the distinct effects of PLA and PVC microplastics on microbial communities and highlight the role of microplastics in ARG dissemination, emphasizing their ecological risks in aquatic ecosystems.202540712359
7930120.9929Fates of extracellular and intracellular antibiotic resistance genes in activated sludge and plastisphere under sulfadiazine pressure. Microplastics, antibiotics, and antibiotic resistance genes (ARGs) represent prominent emerging contaminants that can potentially hinder the efficacy of biological wastewater treatment and pose health risks. Plastisphere as a distinct ecological niche for microorganisms, acts as a repository for ARGs and potential pathogenic bacteria. Nonetheless, the spread pattern of extracellular ARGs (eARGs) and intracellular ARGs (iARGs) in plastisphere under antibiotic exposure was not yet known. This study aimed to investigate disparities in extracellular polymeric substances (EPS) production, extracellular and intracellular microbial community structures, as well as the transmission of eARGs and iARGs between activated sludge and plastisphere in an anaerobic/anoxic/oxic system under sulfadiazine (SDZ) exposure. SDZ was found to enhance EPS production in activated sludge and plastisphere. Interestingly, as SDZ removal efficiency increased, EPS content decreased in activated sludge and plastisphere collected from oxic zone, and continued to increase in plastisphere samples collected from anaerobic and anoxic zones. There were significant differences in microbial community structure between activated sludge and plastisphere, and the DNA fragments of potential pathogenic bacteria were detected in extracellular samples. SDZ exhibited a promoting effect on the propagation of eARGs, which were more abundant in the plastisphere than in activated sludge, thus heightening the risk of ARGs dissemination. Extracellular mobile genetic elements played a pivotal role in driving the spread of eARGs, while the microbial community induced the changes of iARGs. Potential pathogenic bacteria emerged as potential hosts for ARGs and mobile genetic elements within activated sludge and plastisphere, leading to more serious environmental threats.202337898001
8568130.9929Bioremediation potential of sulfadiazine-degrading bacteria: Impacts on ryegrass growth and soil functionality. The extensive use of antibiotics, particularly sulfadiazine (SDZ), has led to significant environmental contamination and the proliferation of antibiotic resistance genes (ARGs). This study investigates the bioremediation potential of two SDZ-degrading bacterial strains, Acinetobacter sp. M9 and Enterobacter sp. H1, and their impact on ryegrass (Lolium perenne) growth and the inter-root microenvironment in SDZ-contaminated soils. A pot experiment combined with amplicon and metagenomic sequencing revealed that inoculation with M9 and H1 significantly enhanced ryegrass growth by alleviating oxidative stress, increasing chlorophyll content, and improving soil nutrient availability. The strains also promoted SDZ degradation efficiency and improved carbon and nitrogen cycling through the upregulation of key functional genes. Furthermore, microbial community analysis demonstrated increased alpha diversity, shifts in dominant taxa, and functional enrichment in pollutant degradation pathways. The dynamics of ARGs revealed a decrease in aminoglycoside, rifamycin, and streptomycin resistance genes, while sulfonamide resistance genes increased due to the residual SDZ stress. These findings highlight the potential of M9 and H1 as sustainable bioremediation agents to mitigate antibiotic contamination, improve soil health, and support plant growth in polluted environments.202540122011
7972140.9929Sulfadiazine proliferated antibiotic resistance genes in the phycosphere of Chlorella pyrenoidosa: Insights from bacterial communities and microalgal metabolites. The phycosphere is an essential ecological niche for the proliferation of antibiotic resistance genes (ARGs). However, how ARGs' potential hosts change and the driving mechanism of metabolites under antibiotic stress in the phycosphere have seldom been researched. We investigated the response of Chlorella pyrenoidosa and the structure and abundance of free-living (FL) and particle-attached (PA) bacteria, ARGs, and metabolites under sulfadiazine by using real-time quantitative PCR, 16 S rRNA high-throughput. The linkage of key bacterial communities, ARGs, and metabolites through correlations was established. Through analysis of physiological indicators, Chlorella pyrenoidosa displayed a pattern of "low-dose promotion and high-dose inhibition" under antibiotic stress. ARGs were enriched in the PA treatment groups by 117 %. At the phylum level, Proteobacteria, Bacteroidetes, and Actinobacteria as potential hosts for ARGs. At the genus level, potential hosts included Sphingopyxis, SM1A02, Aquimonas, Vitellibacter, and Proteiniphilum. Middle and high antibiotic concentrations induced the secretion of metabolites closely related to potential hosts by algae, such as phytosphingosine, Lysophosphatidylcholine, and α-Linolenic acid. Therefore, changes in bacterial communities indirectly influenced the distribution of ARGs through alterations in metabolic products. These findings offer essential details about the mechanisms behind the spread and proliferation of ARGs in the phycosphere.202438795485
8127150.9928Microbial Multitrophic Communities Drive the Variation of Antibiotic Resistome in the Gut of Soil Woodlice (Crustacea: Isopoda). Multitrophic communities inhabit in soil faunal gut, including bacteria, fungi, and protists, which have been considered a hidden reservoir for antibiotic resistance genes (ARGs). However, there is a dearth of research focusing on the relationships between ARGs and multitrophic communities in the gut of soil faunas. Here, we studied the contribution of multitrophic communities to variations of ARGs in the soil woodlouse gut. The results revealed diverse and abundant ARGs in the woodlouse gut. Network analysis further exhibited strong connections between key ecological module members and ARGs, suggesting that multitrophic communities in the keystone ecological cluster may play a pivotal role in the variation of ARGs in the woodlouse gut. Moreover, long-term application of sewage sludge significantly altered the woodlice gut resistome and interkingdom communities. The variation portioning analysis indicated that the fungal community has a greater contribution to variations of ARGs than bacterial and protistan communities in the woodlice gut after long-term application of sewage sludge. Together, our results showed that changes in gut microbiota associated with agricultural practices (e.g., sewage sludge application) can largely alter the gut interkingdom network in ecologically relevant soil animals, with implications for antibiotic resistance, which advances our understanding of the microecological drivers of ARGs in terrestrial ecosystem.202235876241
7949160.9928Tetracycline and quinolone contamination mediate microbial and antibiotic resistant gene composition in epiphytic biofilms of mesocosmic wetlands. The fate and ecological impact of antibiotics on aquatic ecosystems have not been properly elucidated in mesocosm wetlands scale. This study explored how tetracyclines (TCs, including tetracycline TC and oxytetracycline) and fluoroquinolones (QNs, including ciprofloxacin CIP and levofloxacin) affect mesocosm wetlands vegetated by V. spiralis, focusing on their impact on epiphytic biofilm microbial communities and antibiotic resistance genes (ARGs). Results showed that submerged plants absorbed more antibiotics than sediment. Both TCs and QNs disrupted microbial communities in different ways and increased eukaryotic community diversity in a concentration-dependent manner (2-4 mg/L for CIP, 4-8 mg/L for TC). TCs mainly inhibited epiphytic bacteria, while CIP increased bacterial phyla abundance. TC reduced Cyanobacteriota, Acidobacteriota, and Patescibacteria but increased Bacillota, Bacteroidota, and Armatimonadota. In contrast, CIP reduced Bacteroidota, Cyanobacteriota, and Gemmatimonadota but increased Bacillota, Planctomycetota, and Acidobacteriota. Significant differences in ARG profiles were observed between QNs and TCs, with TCs having a more substantial effect on ARGs due to their stronger impact on bacterial communities. Both antibiotics raised ARG levels with higher concentrations, particularly for multidrug resistance, tetracyclines, trimethoprim, sulfonamides, aminoglycosides, and fosfomycin, emphasizing their role in antimicrobial resistance. The study suggests that antibiotics can either stimulate or inhibit ARGs depending on their effects on bacterial communities. This study provides key evidence on the ecological mechanisms underlying the impact of TCs and QNs on epiphytic microbes of mesocosm wetlands.202439321725
8124170.9928Effect of graphene and graphene oxide on antibiotic resistance genes during copper-contained swine manure anaerobic digestion. Copper is an important selectors for antibiotic resistance genes (ARGs) transfer because of metal-antibiotic cross-resistance and/or coresistance. Due to carbon-based materials' good adsorption capacity for heavy metals, graphene and graphene oxide have great potential to reduce ARGs abundance in the environment with copper pollution. To figure out the mechanics, this study investigated the effects of graphene and graphene oxide on the succession of ARGs, mobile genetic elements (MGEs), heavy metal resistance genes (HMRGs), and bacterial communities during copper-contained swine manure anaerobic digestion. Results showed that graphene and graphene oxide could reduce ARGs abundance in varying degrees with the anaerobic reactors that contained a higher concentration of copper. Nevertheless, graphene decreased the abundance of ARGs more effectively than graphene oxide. Phylum-level bacteria such as Firmicutes, Bacteroidetes, Spirochaetes, and Verrucomicrobiaat were significantly positively correlated with most ARGs. Network and redundancy analyses demonstrated that alterations in the bacterial community are one of the main factors leading to the changes in ARGs. Firmicutes, Bacteroidetes, and Spirochaetes were enriched lower in graphene reactor than graphene oxide in anaerobic digestion products, which may be the main reason that graphene is superior to graphene oxide in reduced ARGs abundance. Additionally, ARGs were close to HMRGs than MGEs in the treatments with graphene, the opposite in graphene oxide reactors. Therefore, we speculate that the reduction of HMRGs in graphene may contribute to the result that graphene is superior to graphene oxide in reduced ARGs abundance in anaerobic digestion.202336394812
7887180.9928Double-edged sword effects of sulfate reduction process in sulfur autotrophic denitrification system: Accelerating nitrogen removal and promoting antibiotic resistance genes spread. This study proposed the double-edged sword effects of sulfate reduction process on nitrogen removal and antibiotic resistance genes (ARGs) transmission in sulfur autotrophic denitrification system. Excitation-emission matrix-parallel factor analysis identified the protein-like fraction in soluble microbial products as main endogenous organic matter driving the sulfate reduction process. The resultant sulfide tended to serve as bacterial modulators, augmenting electron transfer processes and mitigating oxidative stress, thereby enhancing sulfur oxidizing bacteria (SOB) activity, rather than extra electron donors. The cooperation between SOB and heterotroph (sulfate reducing bacteria (SRB) and heterotrophic denitrification bacteria (HDB)) were responsible for advanced nitrogen removal, facilitated by multiple metabolic pathways including denitrification, sulfur oxidation, and sulfate reduction. However, SRB and HDB were potential ARGs hosts and assimilatory sulfate reduction pathway positively contributed to ARGs spread. Overall, the sulfate reduction process in sulfur autotrophic denitrification system boosted nitrogen removal process, but also increased the risk of ARGs transmission.202439122125
6932190.9928Distribution of antibiotic resistance genes in soil amended using Azolla imbricata and its driving mechanisms. The floating aquatic plant of Azolla imbricata has an outstanding purification capability for polluted river water, and it is also employed to improve soil fertility. However, the occurrence and distribution of antibiotic resistance genes (ARGs) in soil amended using A.imbricata remain unclear. In the soil amendment with A. imbricata, heavy metals, antibiotics, transposase genes, ARGs, and bacterial communities in the soil were determined in this study. The results indicated that the diversity of bacteria and ARGs increased, while the diversity of ARGs decreased under the amendment using an appropriate amount of A. imbricata. The Firmicutes, Chloroflexi, Actinobacteria, and Cyanobacteria were the main host bacteria of ARGs. The vertical gene transfer of ARGs was weak, and the horizontal gene transfer became the dominant transfer pathway of ARGs. The amendment with A. imbricata altered the distribution of heavy metals, antibiotics, transposase genes, ARGs, and dominant bacteria. The amendment using A. imbricata promoted the degradation of antibiotics, decreased the concentrations of available heavy metals, and eliminated the abundance of ARGs and transposase genes. Our findings suggested a comprehensive effect of multiple stresses on the fate of ARGs in soil amended with A. imbricata, providing an insight into the distribution and propagation of ARGs in soil amended using plant residues.201931351286