# | Rank | Similarity | Title + Abs. | Year | PMID |
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 |
| 806 | 0 | 0.9730 | A two-component small multidrug resistance pump functions as a metabolic valve during nicotine catabolism by Arthrobacter nicotinovorans. The genes nepAB of a small multidrug resistance (SMR) pump were identified as part of the pAO1-encoded nicotine regulon responsible for nicotine catabolism in Arthrobacter nicotinovorans. When [(14)C]nicotine was added to the growth medium the bacteria exported the (14)C-labelled end product of nicotine catabolism, methylamine. In the presence of the proton-motive force inhibitors 2,4-dinitrophenol (DNP), carbonyl cyanide m-chlorophenylhydrazone (CCCP) or the proton ionophore nigericin, export of methylamine was inhibited and radioactivity accumulated inside the bacteria. Efflux of [(14)C]nicotine-derived radioactivity from bacteria was also inhibited in a pmfR : cmx strain with downregulated nepAB expression. Because of low amine oxidase levels in the pmfR : cmx strain, gamma-N-methylaminobutyrate, the methylamine precursor, accumulated. Complementation of this strain with the nepAB genes, carried on a plasmid, restored the efflux of nicotine breakdown products. Both NepA and NepB were required for full export activity, indicating that they form a two-component efflux pump. NepAB may function as a metabolic valve by exporting methylamine, the end product of nicotine catabolism, and, in conditions under which it accumulates, the intermediate gamma-N-methylaminobutyrate. | 2007 | 17464069 |
| 7828 | 1 | 0.9713 | Simultaneous elimination of antibiotic-resistant bacteria and antibiotic resistance genes by different Fe-N co-doped biochars activating peroxymonosulfate: The key role of pyridine-N and Fe-N sites. The coexistence of antibiotic resistance genes (ARGs) and antibiotic-resistant bacteria (ARB) in the environment poses a potential threat to public health. In our study, we have developed a novel advanced oxidation process for simultaneously removing ARGs and ARB by two types of iron and nitrogen-doped biochar derived from rice straw (FeN-RBC) and sludge (FeN-SBC). All viable ARB (approximately 10(8) CFU mL(-1)) was inactivated in the FeN-RBC/ peroxymonosulfate (PMS) system within 40 min and did not regrow after 48 h even in real water samples. Flow cytometry identified 96.7 % of dead cells in the FeN-RBC/PMS system, which verified the complete inactivation of ARB. Thorough disinfection of ARB was associated with the disruption of cell membranes and intracellular enzymes related to the antioxidant system. Whereas live bacteria (approximately 200 CFU mL(-1)) remained after FeN-SBC/PMS treatment. Intracellular and extracellular ARGs (tetA and tetB) were efficiently degraded in the FeN-RBC/PMS system. The production of active species, primarily •OH, SO(4)(•-) and Fe (IV), as well as electron transfer, were essential to the effective disinfection of FeN-RBC/PMS. In comparison with FeN-SBC, the better catalytic performance of FeN-RBC was mainly ascribed to its higher amount of pyridine-N and Fe(0), and more reactive active sites (such as CO group and Fe-N sites). Density functional theory calculations indicated the greater adsorption energy and Bader charge, more stable Fe-O bond, more easily broken OO bond in FeN-RBC/PMS, which demonstrated the stronger electron transfer capacity between FeN-RBC and PMS. To encapsulate, our study provided an efficient and dependable method for the simultaneous elimination of ARGs and ARB in water. | 2024 | 38669989 |
| 8740 | 2 | 0.9713 | Nitrite reductase activity of sulphate-reducing bacteria prevents their inhibition by nitrate-reducing, sulphide-oxidizing bacteria. Sulphate-reducing bacteria (SRB) can be inhibited by nitrate-reducing, sulphide-oxidizing bacteria (NR-SOB), despite the fact that these two groups are interdependent in many anaerobic environments. Practical applications of this inhibition include the reduction of sulphide concentrations in oil fields by nitrate injection. The NR-SOB Thiomicrospira sp. strain CVO was found to oxidize up to 15 mM sulphide, considerably more than three other NR-SOB strains that were tested. Sulphide oxidation increased the environmental redox potential (Eh) from -400 to +100 mV and gave 0.6 nitrite per nitrate reduced. Within the genus Desulfovibrio, strains Lac3 and Lac6 were inhibited by strain CVO and nitrate for the duration of the experiment, whereas inhibition of strains Lac15 and D. vulgaris Hildenborough was transient. The latter had very high nitrite reductase (Nrf) activity. Southern blotting with D. vulgaris nrf genes as a probe indicated the absence of homologous nrf genes from strains Lac3 and Lac6 and their presence in strain Lac15. With respect to SRB from other genera, inhibition of the known nitrite reducer Desulfobulbus propionicus by strain CVO and nitrate was transient, whereas inhibition of Desulfobacterium autotrophicum and Desulfobacter postgatei was long-lasting. The results indicate that inhibition of SRB by NR-SOB is caused by nitrite production. Nrf-containing SRB can overcome this inhibition by further reducing nitrite to ammonia, preventing a stalling of the favourable metabolic interactions between these two bacterial groups. Nrf, which is widely distributed in SRB, can thus be regarded as a resistance factor that prevents the inhibition of dissimilatory sulphate reduction by nitrite. | 2003 | 12823193 |
| 8487 | 3 | 0.9710 | Mechanisms of nano zero-valent iron in enhancing dibenzofuran degradation by a Rhodococcus sp.: Trade-offs between ATP production and protection against reactive oxygen species. Nano zero-valent iron (nZVI) can enhance pollutants biodegradation, but it displays toxicity towards microorganisms. Gram-positive (G(+)) bacteria exhibit greater resistance to nZVI than Gram-negative bacteria. However, mechanisms of nZVI accelerating pollutants degradation by G(+) bacteria remain unclear. Herein, we explored effects of nZVI on a G(+) bacterium, Rhodococcus sp. strain p52, and mechanisms by which nZVI accelerates biodegradation of dibenzofuran, a typical polycyclic aromatic compound. Electron microscopy and energy dispersive spectroscopy analysis revealed that nZVI could penetrate cell membranes, which caused damage and growth inhibition. nZVI promoted dibenzofuran biodegradation at certain concentrations, while higher concentration functioned later due to the delayed reactive oxygen species (ROS) mitigation. Transcriptomic analysis revealed that cells adopted response mechanisms to handle the elevated ROS induced by nZVI. ATP production was enhanced by accelerated dibenzofuran degradation, providing energy for protein synthesis related to antioxidant stress and damage repair. Meanwhile, electron transport chain (ETC) was adjusted to mitigate ROS accumulation, which involved downregulating expression of ETC complex I-related genes, as well as upregulating expression of the genes for the ROS-scavenging cytochrome bd complex and ETC complex II. These findings revealed the mechanisms underlying nZVI-enhanced biodegradation by G(+) bacteria, offering insights into optimizing bioremediation strategies involving nZVI. | 2025 | 39549579 |
| 196 | 4 | 0.9708 | A specialized citric acid cycle requiring succinyl-coenzyme A (CoA):acetate CoA-transferase (AarC) confers acetic acid resistance on the acidophile Acetobacter aceti. Microbes tailor macromolecules and metabolism to overcome specific environmental challenges. Acetic acid bacteria perform the aerobic oxidation of ethanol to acetic acid and are generally resistant to high levels of these two membrane-permeable poisons. The citric acid cycle (CAC) is linked to acetic acid resistance in Acetobacter aceti by several observations, among them the oxidation of acetate to CO2 by highly resistant acetic acid bacteria and the previously unexplained role of A. aceti citrate synthase (AarA) in acetic acid resistance at a low pH. Here we assign specific biochemical roles to the other components of the A. aceti strain 1023 aarABC region. AarC is succinyl-coenzyme A (CoA):acetate CoA-transferase, which replaces succinyl-CoA synthetase in a variant CAC. This new bypass appears to reduce metabolic demand for free CoA, reliance upon nucleotide pools, and the likely effect of variable cytoplasmic pH upon CAC flux. The putative aarB gene is reassigned to SixA, a known activator of CAC flux. Carbon overflow pathways are triggered in many bacteria during metabolic limitation, which typically leads to the production and diffusive loss of acetate. Since acetate overflow is not feasible for A. aceti, a CO(2) loss strategy that allows acetic acid removal without substrate-level (de)phosphorylation may instead be employed. All three aar genes, therefore, support flux through a complete but unorthodox CAC that is needed to lower cytoplasmic acetate levels. | 2008 | 18502856 |
| 653 | 5 | 0.9699 | Connecting Algal Polysaccharide Degradation to Formaldehyde Detoxification. Formaldehyde is a toxic metabolite that is formed in large quantities during bacterial utilization of the methoxy sugar 6-O-methyl-d-galactose, an abundant monosaccharide in the red algal polysaccharide porphyran. Marine bacteria capable of metabolizing porphyran must therefore possess suitable detoxification systems for formaldehyde. We demonstrate here that detoxification of formaldehyde in the marine Flavobacterium Zobellia galactanivorans proceeds via the ribulose monophosphate pathway. Simultaneously, we show that the genes encoding the key enzymes of this pathway are important for maintaining high formaldehyde resistance. Additionally, these genes are upregulated in the presence of porphyran, allowing us to connect porphyran degradation to the detoxification of formed formaldehyde. | 2022 | 35561127 |
| 7860 | 6 | 0.9696 | Enhanced removal of antibiotic-resistant bacteria and resistance genes by three-dimensional electrochemical process using MgFe(2)O(4)-loaded biochar as both particle electrode and catalyst for peroxymonosulfate activation. In this study, MgFe(2)O(4)-loaded biochar (MFBC) was used as a three-dimensional particle electrode to active peroxymonosulfate (EC/MFBC/PMS) for the removal of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs). The results demonstrated that, under the conditions of 1.0 mM PMS concentration, 0.4 g/L material dosage, 5 V voltage intensity, and MFBC preparation temperature of 600 °C, the EC/MFBC600/PMS system achieved complete inactivation of E. coli DH5α within 5 min and the intracellular sul1 was reduced by 81.5 % after 30 min of the treatment. Compared to EC and PMS alone treatments, the conjugation transfer frequency of sul1 rapidly declined by 92.9 % within 2 min. The cell membrane, proteins, lipids, as well as intracellular and extracellular ARGs in E. coli DH5α were severely damaged by free radicals in solution and intracellular reactive oxygen species (ROS). Furthermore, up-regulation was observed in genes associated with oxidative stress, SOS response and cell membrane permeability in E. coli DH5α, however, no significant changes were observed in functional genes related to gene conjugation and transfer mechanisms. This study would contribute to the underlying of PMS activation by three-dimensional particle electrode, and provide novel insights into the mechanism of ARB inactivation and ARGs degradation under PMS advanced oxidation treatment. | 2024 | 39197284 |
| 7879 | 7 | 0.9695 | Multidrug-resistant plasmid RP4 increases NO and N(2)O yields via the electron transport system in Nitrosomonas europaea ammonia oxidation. Antibiotic resistance genes (ARGs) have recently become an important public health problem and therefore several studies have characterized ARG composition and distribution. However, few studies have assessed their impact on important functional microorganisms in the environment. Therefore, our study sought to investigate the mechanisms through which multidrug-resistant plasmid RP4 affected the ammonia oxidation capacity of ammonia-oxidizing bacteria, which play a key role in the nitrogen cycle. The ammonia oxidation capacity of N. europaea ATCC25978 (RP4) was significantly inhibited, and NO and N(2)O were produced instead of nitrite. Our findings demonstrated that the decrease in electrons from NH(2)OH decreased the ammonia monooxygenase (AMO) activity, leading to a decrease in ammonia consumption. In the ammonia oxidation process, N. europaea ATCC25978 (RP4) exhibited ATP and NADH accumulation. The corresponding mechanism was the overactivation of Complex Ⅰ, ATPase, and the TCA cycle by the RP4 plasmid. The genes encoding TCA cycle enzymes related to energy generation, including gltA, icd, sucD, and NE0773, were upregulated in N. europaea ATCC25978 (RP4). These results demonstrate the ecological risks of ARGs, including the inhibition of the ammonia oxidation process and an increased production of greenhouse gases such as NO and N(2)O. | 2023 | 37421866 |
| 8486 | 8 | 0.9693 | Multidrug-resistant plasmid modulates ammonia oxidation efficiency in Nitrosomonas europaea through cyclic di-guanylate and acyl-homoserine lactones pathways. Antibiotic resistance genes present a major public health challenge and have potential implications for global biogeochemical cycles. However, their impacts on biological nitrogen removal systems remain poorly understood. In the ammonia-oxidizing bacteria Nitrosomonas europaea ATCC 19718 harboring the multidrug-resistant plasmid RP4, a significant decrease in ammonia oxidation efficiency was observed, accompanied by markedly elevated levels of cyclic di-guanylate (c-di-GMP) and acyl-homoserine lactones (AHLs), compared to plasmid-free controls. The results demonstrated that c-di-GMP facilitates the secretion of AHLs, while elevated levels of AHLs inhibit the ammonia oxidation efficiency of Nitrosomonas europaea ATCC 19718. These results revealed that RP4 plasmid significantly impaired ammonia oxidation efficiency through the c-di-GMP and AHLs pathways. Our findings indicate that the multidrug-resistant plasmid RP4 adversely affects the nitrogen metabolism of ammonia-oxidizing bacteria, potentially disrupting the nitrogen biogeochemical cycle and posing substantial ecological and environmental risks. | 2026 | 40945801 |
| 558 | 9 | 0.9693 | Thiamine pyrophosphate riboswitches are targets for the antimicrobial compound pyrithiamine. Thiamine metabolism genes are regulated in numerous bacteria by a riboswitch class that binds the coenzyme thiamine pyrophosphate (TPP). We demonstrate that the antimicrobial action of the thiamine analog pyrithiamine (PT) is mediated by interaction with TPP riboswitches in bacteria and fungi. For example, pyrithiamine pyrophosphate (PTPP) binds the TPP riboswitch controlling the tenA operon in Bacillus subtilis. Expression of a TPP riboswitch-regulated reporter gene is reduced in transgenic B. subtilis or Escherichia coli when grown in the presence of thiamine or PT, while mutant riboswitches in these organisms are unresponsive to these ligands. Bacteria selected for PT resistance bear specific mutations that disrupt ligand binding to TPP riboswitches and derepress certain TPP metabolic genes. Our findings demonstrate that riboswitches can serve as antimicrobial drug targets and expand our understanding of thiamine metabolism in bacteria. | 2005 | 16356850 |
| 559 | 10 | 0.9692 | Coordinated regulation of chemotaxis and resistance to copper by CsoR in Pseudomonas putida. Copper is an essential enzyme cofactor in bacteria, but excess copper is highly toxic. Bacteria can cope with copper stress by increasing copper resistance and initiating chemorepellent response. However, it remains unclear how bacteria coordinate chemotaxis and resistance to copper. By screening proteins that interacted with the chemotaxis kinase CheA, we identified a copper-binding repressor CsoR that interacted with CheA in Pseudomonas putida. CsoR interacted with the HPT (P1), Dimer (P3), and HATPase_c (P4) domains of CheA and inhibited CheA autophosphorylation, resulting in decreased chemotaxis. The copper-binding of CsoR weakened its interaction with CheA, which relieved the inhibition of chemotaxis by CsoR. In addition, CsoR bound to the promoter of copper-resistance genes to inhibit gene expression, and copper-binding released CsoR from the promoter, leading to increased gene expression and copper resistance. P. putida cells exhibited a chemorepellent response to copper in a CheA-dependent manner, and CsoR inhibited the chemorepellent response to copper. Besides, the CheA-CsoR interaction also existed in proteins from several other bacterial species. Our results revealed a mechanism by which bacteria coordinately regulated chemotaxis and resistance to copper by CsoR. | 2025 | 40197389 |
| 608 | 11 | 0.9692 | Entamoeba histolytica Adaption to Auranofin: A Phenotypic and Multi-Omics Characterization. Auranofin (AF), an antirheumatic agent, targets mammalian thioredoxin reductase (TrxR), an important enzyme controlling redox homeostasis. AF is also highly effective against a diversity of pathogenic bacteria and protozoan parasites. Here, we report on the resistance of the parasite Entamoeba histolytica to 2 µM of AF that was acquired by gradual exposure of the parasite to an increasing amount of the drug. AF-adapted E. histolytica trophozoites (AFAT) have impaired growth and cytopathic activity, and are more sensitive to oxidative stress (OS), nitrosative stress (NS), and metronidazole (MNZ) than wild type (WT) trophozoites. Integrated transcriptomics and redoxomics analyses showed that many upregulated genes in AFAT, including genes encoding for dehydrogenase and cytoskeletal proteins, have their product oxidized in wild type trophozoites exposed to AF (acute AF trophozoites) but not in AFAT. We also showed that the level of reactive oxygen species (ROS) and oxidized proteins (OXs) in AFAT is lower than that in acute AF trophozoites. Overexpression of E. histolytica TrxR (EhTrxR) did not protect the parasite against AF, which suggests that EhTrxR is not central to the mechanism of adaptation to AF. | 2021 | 34439488 |
| 7848 | 12 | 0.9692 | Simultaneous Removal of Antibiotic Resistant Bacteria, Antibiotic Resistance Genes, and Micropollutants by FeS(2)@GO-Based Heterogeneous Photo-Fenton Process. The co-occurrence of various chemical and biological contaminants of emerging concerns has hindered the application of water recycling. This study aims to develop a heterogeneous photo-Fenton treatment by fabricating nano pyrite (FeS(2)) on graphene oxide (FeS(2)@GO) to simultaneously remove antibiotic resistant bacteria (ARB), antibiotic resistance genes (ARGs), and micropollutants (MPs). A facile and solvothermal process was used to synthesize new pyrite-based composites. The GO coated layer forms a strong chemical bond with nano pyrite, which enables to prevent the oxidation and photocorrosion of pyrite and promote the transfer of charge carriers. Low reagent doses of FeS(2)@GO catalyst (0.25 mg/L) and H(2)O(2) (1.0 mM) were found to be efficient for removing 6-log of ARB and 7-log of extracellular ARG (e-ARG) after 30 and 7.5 min treatment, respectively, in synthetic wastewater. Bacterial regrowth was not observed even after a two-day incubation. Moreover, four recalcitrant MPs (sulfamethoxazole, carbamazepine, diclofenac, and mecoprop at an environmentally relevant concentration of 10 μg/L each) were completely removed after 10 min of treatment. The stable and recyclable composite generated more reactive species, including hydroxyl radicals (HO(•)), superoxide radicals (O(2)(• -)), singlet oxygen ((1)O(2)). These findings highlight that the synthesized FeS(2)@GO catalyst is a promising heterogeneous photo-Fenton catalyst for the removal of emerging contaminants. | 2022 | 35759741 |
| 7835 | 13 | 0.9692 | Crouching bacteria, hidden tetA genes in natural waters: Intracellular damage via double persulfate activation (UVA/Fe(2+)/PDS) effectively alleviates the spread of antibiotic resistance. In this study, we elucidated the chemical and biological inactivation mechanisms of peroxydisulfate (PDS) activated by UVA and Fe(2+) (UVA/Fe(2+)/PDS) in wild-type antibiotic-resistant bacteria (ARB) isolated from a river in Inner Mongolia. Among the screened wild-type ARB, the relative abundance of unidentified Enterobacteriaceae, Stenotrophomonas, and Ralstonia was high. A ratio of 1:1 for Fe(2+) and PDS under 18 W·m(-2) UVA radiation (sunny days) completely inactivated the environmental ARB isolates. In the macro view of the inactivation process, Fe(2+) first activates PDS rapidly, and later the UVA energy accumulated starts to activate PDS; HO• then becomes the main active species at a rate-limiting step. From a micro perspective, damage to the cell wall, intracellular proteins, inactivation of antioxidant enzymes, and genetic material degradation are the inactivation series of events by UVA/Fe(2+)/PDS, contributing to the 97.8 % inactivation of ARB at the initial stage. No regrowth of sublethal ARBs was observed. The transfer of tetracycline resistance genes from ARB to lab E. coli was evaluated by horizontal gene transfer (HGT), in which no HGT occurred when ARB was eliminated by UVA/Fe(2+)/PDS. Moreover, the sulfate and iron residuals in the effluents of treated water were lower than the drinking water standards. In summary, PDS, UVA, and Fe(2+) activation effectively inactivated wild ARB with a low concentration of reagents, while inhibiting their regrowth and spread of resistance due to the contribution of intracellular inactivation pathways. | 2024 | 39316921 |
| 561 | 14 | 0.9690 | Regulatory Characterization of Two Cop Systems for Copper Resistance in Pseudomonas putida. Copper ions serve as essential cofactors for many enzymes but exhibit toxicity at elevated concentrations. In Gram-negative bacteria, the Cop system, typically encoded by copABCD, plays a crucial role in maintaining copper homeostasis and detoxification. The chromosome of Pseudomonas putida harbors two copAB clusters but lacks copCD, along with two copR-copS clusters that encode the cognate two-component system. Here, the roles of these Cop components in countering copper toxicity were studied. We found that copAB2 was essential for full resistance to Cu(2+) in P. putida, while copAB1 made only a minor contribution, partially due to its low expression. The two-component systems CopRS1 and CopRS2 both played significant regulatory roles in copper resistance. Although they could compensate for the absence of each other to mediate copper resistance, they exhibited distinct regulatory effects. CopR1 bound to all four cop promoters and activated their transcription under copper stress. In contrast, though CopR2 bound to the same sites as CopR1 in each cop promoter, it significantly activated only copAB2 and copRS2 expression. Its competitive binding at the copAB1 and copRS1 promoters likely impeded CopR1-mediated activation of these genes. Overall, this study reveals the distinct contributions of the two Cop systems to copper resistance and their regulatory interplay in P. putida. | 2025 | 40943098 |
| 8544 | 15 | 0.9689 | Closed fixed-bed bacteria-algae biofilm reactor: A promising solution for phenol containing wastewater treatment and resource transformation. This study focuses on treating phenolic wastewater with a novel closed fixed-bed bacteria-algae biofilm reactor (CF-BABR) to enhance resource transformation for phenolic substances. The CF-BABR showed strong impact - load resistance and stable degradation efficiency, fully degrading phenolic compounds at concentrations from 0 to 150 mg/L. From the inflow to the outflow, the effective sequences, abundance, and diversity of bacteria decreased. Chlorobaculum was the dominant bacterium for phenolic pollutant degradation. The abundance of fungi decreased gradually, while their diversity increased. Kalenjinia and Cutaneotrichosporon played a synergistic role in reducing pollutant toxicity. The high - concentration pollutants at the influent led to a higher abundance of microalgal communities, and Scenedesmaceae became the most dominant algal family, which was positively correlated with the degradation of phenolic compounds. Functional gene prediction indicated that the abundance of functional genes in bacteria decreased overall along the wastewater flow. Carbohydrate metabolism and amino acid metabolism were the most active secondary pathways. In fungi, the predicted gene functions had the highest abundance in the upstream region. Metabolic intermediates such as organic acids and derivatives, lipids and lipid - like molecules, and carboxylic acids and derivatives demonstrated the degradation effect of CF-BABR on phenolic compounds. | 2025 | 40194331 |
| 7861 | 16 | 0.9689 | The removal of antibiotic resistant bacteria and genes and inhibition of the horizontal gene transfer by contrastive research on sulfidated nanoscale zerovalent iron activating peroxymonosulfate or peroxydisulfate. Antibiotic resistant bacteria (ARB) and the antibiotic resistance genes (ARGs) dissemination via plasmid-mediated conjugation have attracted considerable attentions. In this research, sulfidated nanoscale zerovalent iron (S-nZVI)/peroxymonosulfate (PMS) and S-nZVI/peroxydisulfate (PDS) process were investigated to inactivate ARB (Escherichia coli DH5α with RP4 plasmid, Pseudomonas. HLS-6 contains sul1 and intI1 on genome DNA sequence). S-nZVI/PMS system showed higher efficiency than S-nZVI/PDS on ARB inactivation. Thus, the optimal condition 28 mg/L S-nZVI coupled with 153.7 mg/L (0.5 mM) PMS was applied to remove both intracellular ARGs (iARGs) and ARB. The oxidative damage of ARB cell was systemically studied by cell viability, intracellular Mg(2+) levels, the changes of extracellular and internal structure, integrity of cell walls and membranes and enzymatic activities. S-nZVI/PMS effectively inactivated ARB (~7.32 log) within 15 min. These effects were greatly higher than those achieved individually. Moreover, removal efficiencies of iARGs sul1, intI1 and tetA were 1.52, 1.79 and 1.56 log, respectively. These results revealed that S-nZVI and PMS have a synergistic effect against ARB and iARGs. The regrowth assays illustrated that the ARB were effectively inactivated. By verifying the inhibitory impacts of S-nZVI/PMS treatment on conjugation transfer, this work highlights a promising alternative technique for inhibiting the horizontal gene transfer. | 2022 | 34482079 |
| 7887 | 17 | 0.9689 | Double-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. | 2024 | 39122125 |
| 7872 | 18 | 0.9689 | Quaternary 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. | 2023 | 36444811 |
| 7880 | 19 | 0.9688 | The synergistic mechanism of β-lactam antibiotic removal between ammonia-oxidizing microorganisms and heterotrophs. Nitrifying system is an effective strategy to remove numerous antibiotics, however, the contribution of ammonia-oxidizing bacteria (AOB), ammonia-oxidizing archaea (AOA) and heterotrophs for antibiotic removal are still unclear. In this study, the mechanism of β-lactam antibiotic (cefalexin, CFX) removal was studied in a nitrifying sludge system. Results showed that CFX was synergistically removed by AOB (Nitrosomonas, played a major role) and AOA (Candidatus_Nitrososphaera) through ammonia monooxygenase-mediated co-metabolism, and by heterotrophs (Pseudofulvimonas, Hydrogenophaga, RB41, Thauera, UTCFX1, Plasticicumulans, Phaeodactylibacter) through antibiotic resistance genes (ARGs)-encoded β-lactamases-mediated hydrolysis. Regardless of increased archaeal and heterotrophic CFX removal with the upregulation of amoA in AOA and ARGs, the system exhibited poorer CFX removal performance at 10 mg/L, mainly due to the inhibition of AOB. This study provides new reference for the important roles of heterotrophs and ARGs, opening the possibilities for the application of ARGs in antibiotic biodegradation. | 2023 | 36174754 |