NS - Word Related Documents




#
Rank
Similarity
Title + Abs.
Year
PMID
012345
60800.9886Entamoeba 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.202134439488
9510.9886NtPR1a regulates resistance to Ralstonia solanacearum in Nicotiana tabacum via activating the defense-related genes. Pathogenesis-related proteins (PRs) are associated with the development of systemic acquired resistance (SAR) against further infection enforced by fungi, bacteria and viruses. PR1a is the first PR-1 member that could be purified and characterized. Previous studies have reported its role in plants' resistance system against oomycete pathogens. However, the role of PR1a in Solanaceae plants against the bacterial wilt pathogen Ralstonia solanacearum remains unclear. To assess roles of NtPR1a in tobacco responding to R. solanacearum, we performed overexpression experiments in Yunyan 87 plants (a susceptible tobacco cultivar). The results illuminated that overexpression of NtPR1a contributed to improving resistance to R. solanacearum in tobacco Yunyan 87. Specifically speaking, NtPR1a gene could be induced by exogenous hormones like salicylic acid (SA) and pathogenic bacteria R. Solanacearum. Moreover, NtPR1a-overexpressing tobacco significantly reduced multiple of R. solanacearum and inhibited the development of disease symptoms compared with wild-type plants. Importantly, overexpression of NtPR1a activated a series of defense-related genes expression, including the hypersensitive response (HR)-associated genes NtHSR201 and NtHIN1, SA-, JA- and ET-associated genes NtPR2, NtCHN50, NtPR1b, NtEFE26, and Ntacc oxidase, and detoxification-associated gene NtGST1. In summary, our results suggested that NtPR1a-enhanced tobacco resistance to R. solanacearum may be mainly dependent on activation of the defense-related genes.201930545635
997920.9884Type II and IV toxin-antitoxin systems coordinately stabilize the integrative and conjugative element of the ICESa2603 family conferring multiple drug resistance in Streptococcus suis. Integrative and conjugative elements (ICEs) play a vital role in bacterial evolution by carrying essential genes that confer adaptive functions to the host. Despite their importance, the mechanism underlying the stable inheritance of ICEs, which is necessary for the acquisition of new traits in bacteria, remains poorly understood. Here, we identified SezAT, a type II toxin-antitoxin (TA) system, and AbiE, a type IV TA system encoded within the ICESsuHN105, coordinately promote ICE stabilization and mediate multidrug resistance in Streptococcus suis. Deletion of SezAT or AbiE did not affect the strain's antibiotic susceptibility, but their duple deletion increased susceptibility, mainly mediated by the antitoxins SezA and AbiEi. Further studies have revealed that SezA and AbiEi affect the genetic stability of ICESsuHN105 by moderating the excision and extrachromosomal copy number, consequently affecting the antibiotic resistance conferred by ICE. The DNA-binding proteins AbiEi and SezA, which bind palindromic sequences in the promoter, coordinately modulate ICE excision and extracellular copy number by binding to sequences in the origin-of-transfer (oriT) and the attL sites, respectively. Furthermore, AbiEi negatively regulates the transcription of SezAT by binding directly to its promoter, optimizing the coordinate network of SezAT and AbiE in maintaining ICESsuHN105 stability. Importantly, SezAT and AbiE are widespread and conserved in ICEs harbouring diverse drug-resistance genes, and their coordinated effects in promoting ICE stability and mediating drug resistance may be broadly applicable to other ICEs. Altogether, our study uncovers the TA system's role in maintaining the genetic stability of ICE and offers potential targets for overcoming the dissemination and evolution of drug resistance.202438640137
2530.9881Ectopic expression of Tsi1 in transgenic hot pepper plants enhances host resistance to viral, bacterial, and oomycete pathogens. In many plants, including hot pepper plants, productivity is greatly affected by pathogen attack. We reported previously that tobacco stress-induced gene 1 (Tsi1) may play an important role in regulating stress responsive genes and pathogenesis-related (PR) genes. In this study, we demonstrated that overexpression of Tsi1 gene in transgenic hot pepper plants induced constitutive expression of several PR genes in the absence of stress or pathogen treatment. The transgenic hot pepper plants expressing Tsi1 exhibited resistance to Pepper mild mottle virus (PMMV) and Cucumber mosaic virus (CMV). Furthermore, these transgenic plants showed increased resistance to a bacterial pathogen, Xanthomonas campestris pv. vesicatoria and also an oomycete pathogen, Phytophthora capsici. These results suggested that ectopic expression of Tsi1 in transgenic hot pepper plants enhanced the resistance of the plants to various pathogens, including viruses, bacteria, and oomycete. These results suggest that using transcriptional regulatory protein genes may contribute to developing broad-spectrum resistance in crop plants.200212437295
997840.9881Pathogen-encoded Rum DNA polymerase drives rapid bacterial drug resistance. The acquisition of multidrug resistance by pathogenic bacteria is a potentially incipient pandemic. Horizontal transfer of DNA from mobile integrative conjugative elements (ICEs) provides an important way to introduce genes that confer antibiotic (Ab)-resistance in recipient cells. Sizable numbers of SXT/R391 ICEs encode a hypermutagenic Rum DNA polymerase (Rum pol), which has significant homology with Escherichia coli pol V. Here, we show that even under tight transcriptional and post-transcriptional regulation imposed by host bacteria and the R391 ICE itself, Rum pol rapidly accelerates development of multidrug resistance (CIPR, RifR, AmpR) in E. coli in response to SOS-inducing Ab and non-Ab external stressors bleomycin (BLM), ciprofloxacin (CIP) and UV radiation. The impact of Rum pol on the rate of acquisition of drug resistance appears to surpass potential contributions from other cellular processes. We have shown that RecA protein plays a central role in controlling the ability of Rum pol to accelerate antibiotic resistance. A single amino acid substitution in RecA, M197D, acts as a 'Master Regulator' that effectively eliminates the Rum pol-induced Ab resistance. We suggest that Rum pol should be considered as one of the major factors driving development of de novo Ab resistance in pathogens carrying SXT/R391 ICEs.202439413207
860050.9880Does the herbicide napropamide exhibit enantioselective effects across genus plasmid transfer from Escherichia coli to Bacillus subtilis? The dissemination of plasmid-borne antibiotic resistance genes (ARGs) into the environment is an urgent concern. However, the enantioselective effects of herbicides on plasmid conjugation among bacterial genera and their underlying mechanisms remain unclear. This study demonstrates for the first time that the herbicide napropamide (NAP), commonly used in vegetable fields, exhibits a concentration-dependent effect on the transfer efficiency of the pBE2R plasmid from Escherichia coli to Bacillus subtilis. Notably, at a concentration of 5 mg L(-1), R-NAP increased transfer efficiency by threefold compared to the S-enantiomer. Scanning electron microscopy revealed that R-NAP caused less structural damage to bacteria than S-NAP but more effectively reduced cell wall components (lipopolysaccharides and peptidoglycan) in donor and recipient bacteria, increasing reactive oxygen species levels and membrane permeability. Transcriptomic analysis indicated that NAP enantiomers altered the expression of genes related to membrane transport activity and transposons. Cross-domain network analysis identified yieK, ygeH, and ydbL as key genes mediating conjugation transfer. Molecular docking results showed that NAP likely interacts hydrophobically with the active sites of the proteins encoded by these genes. In conclusion, herbicides like R-NAP should be carefully managed in fields irrigated with livestock manure to mitigate the risk of ARG transfer and accumulation in crops.202539637801
848860.9879Antihistamine drug loratadine at environmentally relevant concentrations promotes conjugative transfer of antibiotic resistance genes: Coeffect of oxidative stress and ion transport. Due to the widespread use of loratadine (LOR) as an antihistamine, it is widely distributed in the environment as an emerging contaminant. However, its impact on the dissemination of antibiotic resistance genes (ARGs) remains unclear. This study investigated the effect of LOR on the conjugative transfer of ARGs and elucidated the potential mechanisms through transcriptome analysis. The results showed that LOR significantly promoted the frequency of conjugative transfer up to 1.5- to 8.6-fold higher compared with the control group. Exposure to LOR increased reactive oxidative species (ROS) and intracellular Ca(2+) concentrations, leading to the upregulation of expression of genes related to transmembrane transport and SOS response. Meanwhile, it stimulated the increase of cell membrane permeability. Moreover, LOR exposure could enhance H(+) efflux in donor bacteria, resulting in the decrease of intracellular pH and the elevation of transmembrane potential, which could induce the increase of ion transport, thereby promoting plasmid efflux from the cell membrane. Based on this, we inferred that LOR can induce an increase in ROS level and intracellular Ca(2+) concentrations, and promoted the efflux of intracellular H(+). This, in turn, triggered the intensification of various ion transport processes on the cell membrane, thereby increasing membrane permeability and accelerating plasmid efflux. Ultimately, the coeffect of oxidative stress response and ion transport promoted conjugative transfer. This study demonstrated that LOR significantly promotes plasmid-mediated conjugative transfer of ARGs, providing novel insights into the mechanisms underlying this process.202539919578
848970.9879Signaling molecules accelerate the transmission of antibiotic resistance genes under the stress of copper. Heavy metals can accelerate the dissemination of antibiotic resistance genes (ARGs) in aquatic environments by imposing environmental stresses. Signaling molecules play a role in bacterial communication and help bacteria adapt to environmental stresses. However, little is known whether the presence of signaling molecules has an effect on the spread of ARGs induced by heavy metals. In this study, we investigated how N-decanoyl-L-homoserine lactone (C10-HSL) affects copper-induced conjugative transfer of ARGs. We calculated the conjugative transfer frequency and measured reactive oxygen species (ROS) production, membrane permeability, and the expression of relevant genes. The results demonstrated that the addition of C10-HSL increased the conjugative transfer frequency of ARGs under copper ions (Cu(2+)) stress, showing a 7.2-fold increase under 0.5 μM Cu(2+) and 0.39 μM C10-HSL treatment compared to the control. This enhancement was associated with elevated intracellular ROS production and increased membrane permeability. The reduced conjugative transfer frequency under anaerobic conditions or with thiourea treatment supported the key role of ROS in this process. Furthermore, ROS overproduction triggered the SOS response, as evidenced by a 9-fold upregulation of recA expression. C10-HSL also modulated membrane-associated gene expression by upregulating outer membrane porins and downregulating efflux pump genes under Cu(2+)stress. This study provides a new insight into the spread of ARGs in aquatic environments.202540840413
819280.9879Resisting the Heat: Bacterial Disaggregases Rescue Cells From Devastating Protein Aggregation. Bacteria as unicellular organisms are most directly exposed to changes in environmental growth conditions like temperature increase. Severe heat stress causes massive protein misfolding and aggregation resulting in loss of essential proteins. To ensure survival and rapid growth resume during recovery periods bacteria are equipped with cellular disaggregases, which solubilize and reactivate aggregated proteins. These disaggregases are members of the Hsp100/AAA+ protein family, utilizing the energy derived from ATP hydrolysis to extract misfolded proteins from aggregates via a threading activity. Here, we describe the two best characterized bacterial Hsp100/AAA+ disaggregases, ClpB and ClpG, and compare their mechanisms and regulatory modes. The widespread ClpB disaggregase requires cooperation with an Hsp70 partner chaperone, which targets ClpB to protein aggregates. Furthermore, Hsp70 activates ClpB by shifting positions of regulatory ClpB M-domains from a repressed to a derepressed state. ClpB activity remains tightly controlled during the disaggregation process and high ClpB activity states are likely restricted to initial substrate engagement. The recently identified ClpG (ClpK) disaggregase functions autonomously and its activity is primarily controlled by substrate interaction. ClpG provides enhanced heat resistance to selected bacteria including pathogens by acting as a more powerful disaggregase. This disaggregase expansion reflects an adaption of bacteria to extreme temperatures experienced during thermal based sterilization procedures applied in food industry and medicine. Genes encoding for ClpG are transmissible by horizontal transfer, allowing for rapid spreading of extreme bacterial heat resistance and posing a threat to modern food production.202134017857
58890.9876Enhanced aphid detoxification when confronted by a host with elevated ROS production. Reactive oxygen species (ROS) plays an important role in plant defense responses against bacteria, fungi and insect pests. Most recently, we have demonstrated that loss of Arabidopsis thaliana BOTRYTIS-INDUCED KINASE1 (BIK1) function releases its suppression of aphid-induced H2O2 production and cell death, rendering the bik1 mutant more resistant to green peach aphid (Myzus persicae) than wild-type plants. However, little is known regarding how ROS-related gene expression is correlated with bik1-mediated resistance to aphids, or whether these aphids biochemically respond to the oxidative stress. Here, we show that the bik1 mutant exhibited elevated basal expression of ROS-generating and -responsive genes, but not ROS-metabolizing genes. Conversely, we detected enhanced detoxification enzymatic activities in aphids reared on bik1 plants compared to those on wild-type plants, suggesting that aphids counter the oxidative stress associated with bik1 through elevated metabolic resistance.201525932782
667100.9876Increased intracellular H(2)S levels enhance iron uptake in Escherichia coli. We investigated the impact of intracellular hydrogen sulfide (H(2)S) hyperaccumulation on the transcriptome of Escherichia coli. The wild-type (WT) strain overexpressing mstA, encoding 3-mercaptopyruvate sulfur transferase, produced significantly higher H(2)S levels than the control WT strain. The mstA-overexpressing strain exhibited increased resistance to antibiotics, supporting the prior hypothesis that intracellular H(2)S contributes to oxidative stress responses and antibiotic resistance. RNA-seq analysis revealed that over 1,000 genes were significantly upregulated or downregulated upon mstA overexpression. The upregulated genes encompassed those associated with iron uptake, including siderophore synthesis and iron import transporters. The mstA-overexpressing strain showed increased levels of intracellular iron content, indicating that H(2)S hyperaccumulation affects iron availability within cells. We found that the H(2)S-/supersulfide-responsive transcription factor YgaV is required for the upregulated expression of iron uptake genes in the mstA-overexpression conditions. These findings indicate that the expression of iron uptake genes is regulated by intracellular H(2)S, which is crucial for oxidative stress responses and antibiotic resistance in E. coli. IMPORTANCE: H(2)S is recognized as a second messenger in bacteria, playing a vital role in diverse intracellular and extracellular activities, including oxidative stress responses and antibiotic resistance. Both H(2)S and iron serve as essential signaling molecules for gut bacteria. However, the intricate intracellular coordination between them, governing bacterial physiology, remains poorly understood. This study unveils a close relationship between intracellular H(2)S accumulation and iron uptake activity, a relationship critical for antibiotic resistance. We present additional evidence expanding the role of intracellular H(2)S synthesis in bacterial physiology.202439324809
24110.9875Environmental History Modulates Arabidopsis Pattern-Triggered Immunity in a HISTONE ACETYLTRANSFERASE1-Dependent Manner. In nature, plants are exposed to a fluctuating environment, and individuals exposed to contrasting environmental factors develop different environmental histories. Whether different environmental histories alter plant responses to a current stress remains elusive. Here, we show that environmental history modulates the plant response to microbial pathogens. Arabidopsis thaliana plants exposed to repetitive heat, cold, or salt stress were more resistant to virulent bacteria than Arabidopsis grown in a more stable environment. By contrast, long-term exposure to heat, cold, or exposure to high concentrations of NaCl did not provide enhanced protection against bacteria. Enhanced resistance occurred with priming of Arabidopsis pattern-triggered immunity (PTI)-responsive genes and the potentiation of PTI-mediated callose deposition. In repetitively stress-challenged Arabidopsis, PTI-responsive genes showed enrichment for epigenetic marks associated with transcriptional activation. Upon bacterial infection, enrichment of RNA polymerase II at primed PTI marker genes was observed in environmentally challenged Arabidopsis. Finally, repetitively stress-challenged histone acetyltransferase1-1 (hac1-1) mutants failed to demonstrate enhanced resistance to bacteria, priming of PTI, and increased open chromatin states. These findings reveal that environmental history shapes the plant response to bacteria through the development of a HAC1-dependent epigenetic mark characteristic of a primed PTI response, demonstrating a mechanistic link between the primed state in plants and epigenetics.201424963055
8601120.9874Herbicide promotes the conjugative transfer of multi-resistance genes by facilitating cellular contact and plasmid transfer. The global dissemination of antibiotic resistance genes (ARGs), especially via plasmid-mediated horizontal transfer, is becoming a pervasive health threat. While our previous study found that herbicides can accelerate the horizontal gene transfer (HGT) of ARGs in soil bacteria, the underlying mechanisms by which herbicides promote the HGT of ARGs across and within bacterial genera are still unclear. Here, the underlying mechanism associated with herbicide-promoted HGT was analyzed by detecting intracellular reactive oxygen species (ROS) production, extracellular polymeric substance composition, cell membrane integrity and proton motive force combined with genome-wide RNA sequencing. Exposure to herbicides induced a series of the above bacterial responses to promote HGT except for the ROS response, including compact cell-to-cell contact by enhancing pilus-encoded gene expression and decreasing cell surface charge, increasing cell membrane permeability, and enhancing the proton motive force, providing additional power for DNA uptake. This study provides a mechanistic understanding of the risk of bacterial resistance spread promoted by herbicides, which elucidates a new perspective on nonantibiotic agrochemical acceleration of the HGT of ARGs.202234969463
8982130.9874Ampicillin Exposure and Glutathione Deficiency Synergistically Promote Conjugative Transfer of Plasmid-Borne Antibiotic Resistance Genes. Plasmid-mediated conjugation is an important pathway for the spread of antibiotic resistance genes (ARGs), posing a significant risk to global public health. It has been reported that the conjugative transfer of ARGs could be enhanced by oxidative stress. Whether endogenous glutathione (GSH), a major non-protein thiol compound involved in cellular redox homeostasis, influences conjugative transfer is unknown. In this study, we show that the deletion of the GSH biosynthesis gene gshA and ampicillin exposure synergistically promoted the conjugative transfer of plasmid RP4 bearing multiple ARGs from the soil bacterium Enterobacter sp. CZ-1 to Escherichia coli S17-1λπ in co-culture experiments and to diverse soil bacteria belonging to eight phyla, including some potential human pathogens, in a soil incubation experiment. The deletion of gshA increased ROS generation and cell membrane permeability, and upregulated the expression of the genes involved in intracellular oxidative stress regulation, membrane permeability, plasmid replication, and the SOS response process, especially under ampicillin exposure. These results suggest that endogenous GSH is an important factor affecting the spread of plasmid-borne ARGs. Exposure to antibiotics and environmental stresses that cause a depletion of endogenous GSH in vivo are likely to increase the risk of ARG dissemination in the environment.202540346915
583140.9874MarR family proteins sense sulfane sulfur in bacteria. Members of the multiple antibiotic resistance regulator (MarR) protein family are ubiquitous in bacteria and play critical roles in regulating cellular metabolism and antibiotic resistance. MarR family proteins function as repressors, and their interactions with modulators induce the expression of controlled genes. The previously characterized modulators are insufficient to explain the activities of certain MarR family proteins. However, recently, several MarR family proteins have been reported to sense sulfane sulfur, including zero-valent sulfur, persulfide (R-SSH), and polysulfide (R-SnH, n ≥ 2). Sulfane sulfur is a common cellular component in bacteria whose levels vary during bacterial growth. The changing levels of sulfane sulfur affect the expression of many MarR-controlled genes. Sulfane sulfur reacts with the cysteine thiols of MarR family proteins, causing the formation of protein thiol persulfide, disulfide bonds, and other modifications. Several MarR family proteins that respond to reactive oxygen species (ROS) also sense sulfane sulfur, as both sulfane sulfur and ROS induce the formation of disulfide bonds. This review focused on MarR family proteins that sense sulfane sulfur. However, the sensing mechanisms reviewed here may also apply to other proteins that detect sulfane sulfur, which is emerging as a modulator of gene regulation.202438948149
671150.9873Differential roles of the universal stress proteins of Escherichia coli in oxidative stress resistance, adhesion, and motility. The universal stress protein (UspA) superfamily encompasses a conserved group of proteins that are found in bacteria, archaea, and eukaryotes. Escherichia coli harbors six usp genes--uspA, -C, -D, -E, -F, and -G--the expression of which is triggered by a large variety of environmental insults. The uspA gene is important for survival during cellular growth arrest, but the exact physiological role of the Usp proteins is not known. In this work we have performed phenotypic characterization of mutants with deletions of the six different usp genes. We report on hitherto unknown functions of these genes linked to motility, adhesion, and oxidative stress resistance, and we show that usp functions are both overlapping and distinct. Both UspA and UspD are required in the defense against superoxide-generating agents, and UspD appears also important in controlling intracellular levels of iron. In contrast, UspC is not involved in stress resistance or iron metabolism but is essential, like UspE, for cellular motility. Electron microscopy demonstrates that uspC and uspE mutants are devoid of flagella. In addition, the function of the uspC and uspE genes is linked to cell adhesion, measured as FimH-mediated agglutination of yeast cells. While the UspC and UspE proteins promote motility at the expense of adhesion, the UspF and UspG proteins exhibit the exact opposite effects. We suggest that the Usp proteins have evolved different physiological functions that reprogram the cell towards defense and escape during cellular stress.200516159758
642160.9873Role of histone-like protein H-NS in multidrug resistance of Escherichia coli. The histone-like protein H-NS is a major component of the bacterial nucleoid and plays a crucial role in global gene regulation of enteric bacteria. It is known that the expression of a variety of genes is repressed by H-NS, and mutations in hns result in various phenotypes, but the role of H-NS in the drug resistance of Escherichia coli has not been known. Here we present data showing that H-NS contributes to multidrug resistance by regulating the expression of multidrug exporter genes. Deletion of the hns gene from the DeltaacrAB mutant increased levels of resistance against antibiotics, antiseptics, dyes, and detergents. Decreased accumulation of ethidium bromide and rhodamine 6G in the hns mutant compared to that in the parental strain was observed, suggesting the increased expression of some drug exporter(s) in this mutant. The increased drug resistance and decreased drug accumulation caused by the hns deletion were completely suppressed by deletion of the multifunctional outer membrane channel gene tolC. At least eight drug exporter systems require TolC for their functions. Among these, increased expression of acrEF, mdtEF, and emrKY was observed in the Deltahns strain by quantitative real-time reverse transcription-PCR analysis. The Deltahns-mediated multidrug resistance pattern is quite similar to that caused by overproduction of the AcrEF exporter. Deletion of the acrEF gene greatly suppressed the level of Deltahns-mediated multidrug resistance. However, this strain still retained resistance to some compounds. The remainder of the multidrug resistance pattern was similar to that conferred by overproduction of the MdtEF exporter. Double deletion of the mdtEF and acrEF genes completely suppressed Deltahns-mediated multidrug resistance, indicating that Deltahns-mediated multidrug resistance is due to derepression of the acrEF and mdtEF drug exporter genes.200414973023
6776170.9873Natural sphalerite nanoparticles can accelerate horizontal transfer of plasmid-mediated antibiotic-resistance genes. Minerals and microorganisms are integral parts of natural environments, and they inevitably interact. Antibiotic-resistance genes (ARGs) significantly threaten modern healthcare. However, the effects of natural minerals on ARG propagation in aquatic systems are not fully understood. The present work studied the effects of natural sphalerite (NS) nanoparticles on the horizontal transfer of ARGs from Escherichia coli DH5α (CTX) (donor) to E. coli C600 (Sm) (recipient), and from E. coli DH5α (MCR) (donor) to E. coli C600 (Sm), and their underlying mechanisms. NS particles (0.5-50 mg L(-1)) induced an NS-concentration-dependent increase in conjugative transfer frequency. The underlying mechanisms associated with the facilitated ARG transfer included the production of intracellular reactive oxygen species, the SOS response, changes in bacterial cell morphology, and alteration of mRNA levels of bacterial cell membrane protein-related genes and genes associated with conjugative ARG transfer. The information herein offers new mechanistic understanding of risks of bacterial resistance resulting from NS.202031999971
8492180.9873Promotion effects and mechanisms of molybdenum disulfide on the propagation of antibiotic resistance genes in soil. The rapid development of nanotechnology has aroused considerable attentions toward understanding the effects of engineered nanomaterials (ENMs) on the propagation of antibiotic resistance. Molybdenum disulfide (MoS(2)) is an extensively used ENM and poses potential risks associated with environmental exposure; nevertheless, the role of MoS(2) toward antibiotic resistance genes (ARGs) transfer remains largely unknown. Herein, it was discovered that MoS(2) nanosheets accelerated the horizontal transfer of RP4 plasmid across Escherichia coli in a dose-dependent manner (0.5-10 mg/L), with the maximum transfer frequency 2.07-fold higher than that of the control. Integration of physiological, transcriptomics, and metabolomics analyses demonstrated that SOS response in bacteria was activated by MoS(2) due to the elevation of oxidative damage, accompanied by cell membrane permeabilization. MoS(2) promoted bacterial adhesion and intercellular contact via stimulating the secretion of extracellular polysaccharides. The ATP levels were maximally increased by 305.7 % upon exposure to MoS(2), and the expression of plasmid transfer genes was up-regulated, contributing to the accelerated plasmid conjugation and increased ARG abundance in soil. Our findings highlight the roles of emerging ENMs (e.g., MoS(2)) in ARGs dissemination, which is significant for the safe applications and risk management of ENMs under the development scenarios of nanotechnology.202337062264
8523190.9873Tebuconazole promotes spread of a multidrug-resistant plasmid into soil bacteria to form new resistant bacterial strains. The development of antibiotic resistance threatens human and environmental health. Non-antibiotic stressors, including fungicides, may contribute to the spread of antibiotic resistance genes (ARGs). We determined the promoting effects of tebuconazole on ARG dissemination using a donor, Escherichia coli MG1655, containing a multidrug-resistant fluorescent plasmid (RP4) and a recipient (E. coli HB101). The donor was then incorporated into the soil to test whether tebuconazole could accelerate the spread of RP4 into indigenous bacteria. Tebuconazole promoted the transfer of the RP4 plasmid from the donor into the recipient via overproduction of reactive oxygen species (ROS), enhancement of cell membrane permeability and regulation of related genes. The dissemination of the RP4 plasmid from the donor to soil bacteria was significantly enhanced by tebuconazole. RP4 plasmid could be propagated into more genera of bacteria in tebuconazole-contaminated soil as the exposure time increased. These findings demonstrate that the fungicide tebuconazole promotes the spread of the RP4 plasmid into indigenous soil bacteria, revealing the potential risk of tebuconazole residues enhancing the dissemination of ARGs in soil environments.202438615769