Insights into the Synergistic Antibacterial Activity of Silver Nitrate with Potassium Tellurite Against Pseudomonas aeruginosa
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ABSTRACT:
ORGANISM(S): Pseudomonas aeruginosa
PROVIDER: GSE232832 | GEO | 2023/06/15
REPOSITORIES: GEO
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Project description:Infections associated with antimicrobial-resistant bacteria now represent a significant threat to human health using conventional therapy, necessitating the development of alternate and more effective antibacterial compounds. Silver nanoparticles (Ag NPs) have been proposed as potential antimicrobial agents to combat infections. A complete understanding of their antimicrobial activity is required before these molecules can be used in therapy. Lysozyme coated Ag NPs were synthesized and characterized by TEMEDS, XRD, UV-vis, FTIR spectroscopy, zeta potential, and oxidative potential assay. Biochemical assays and deep level transcriptional analysis using RNA sequencing were used to decipher how Ag NPs exert their antibacterial action against multi-drug resistant Klebsiella pneumoniae MGH78578. RNAseq data revealed that Ag NPs induced a triclosan-like bactericidal mechanism responsible for the inhibition of the type II fatty acid biosynthesis. Additionally, released AgC generated oxidative stress both extra and intracellularly in K. pneumoniae. The data showed that triclosan-like activity and oxidative stress cumulatively underpinned the antibacterial activity of Ag NPs. This result was confirmed by the analysis of the bactericidal effect of Ag NPs against the isogenic K. pneumoniae MGH78578 1soxS mutant, which exhibits a compromised oxidative stress response compared to the wild type. Silver nanoparticles induce a triclosan like antibacterial action mechanism in multi-drug resistant K. pneumoniae. This study extends our understanding of anti-Klebsiella mechanisms associated with exposure to Ag NPs. This allowed us to model how bacteria might develop resistance against silver nanoparticles, should the latter be used in therapy.
2021-01-31 | GSE151953 | GEO
Project description:Applications for silver nanomaterials in consumer products are rapidly expanding, creating an urgent need for toxicological examination of the exposure potential and ecological effects of silver nanoparticles (AgNPs). The integration of genomic techniques into environmental toxicology has presented new avenues to develop exposure biomarkers and investigate the mode of toxicity of novel chemicals. In the present study we used a 15k oligonucleotide microarray for Daphnia magna, a freshwater crustacean and common indicator species for toxicity, to differentiate between particle specific and ionic silver toxicity and to develop exposure biomarkers for citrate-coated and PVP-coated AgNPs. Gene expression profiles revealed that AgNO3 and AgNPs have distinct expression profiles suggesting different modes of toxicity. However, the gene expression profiles of the different coated AgNPs were similar revealing similarities in the cellular effects of these two particles. Major biological processes disrupted by the AgNPs include protein metabolism and signal transduction. In contrast, AgNO3 caused a downregulation of developmental processes, particularly in sensory development. Metal responsive and DNA damage repair genes were induced by the PVP AgNPs, but not the other treatments. In addition, two specific biomarkers were developed for the environmental detection of PVP AgNPs; although further verification under different environmental conditions is needed.
2012-08-05 | GSE35150 | GEO
Project description:The constant, ever-increasing antibiotic resistance crisis leads to the announcement of "urgent, novel antibiotics needed" by the World Health Organization. Our previous works showed a promising synergistic antibacterial activity of silver nitrate with potassium tellurite out of thousands of other metal/metalloid-based antibacterial combinations. The silver-tellurite combined treatment not only is more effective than common antibiotics but also prevents bacterial recovery, decreases the risk of future resistance chance, and decreases the effective concentrations. We demonstrate that the silver-tellurite combination is effective against clinical isolates. Further, this study was conducted to address knowledge gaps in the available data on the antibacterial mechanism of both silver and tellurite, as well as to give insight into how the mixture provides synergism as a combination. Here, we defined the differentially expressed gene profile of Pseudomonas aeruginosa under silver, tellurite, and silver-tellurite combination stress using an RNA sequencing approach to examine the global transcriptional changes in the challenged cultures grown in simulated wound fluid. The study was complemented with metabolomics and biochemistry assays. Both metal ions mainly affected four cellular processes, including sulfur homeostasis, reactive oxygen species response, energy pathways, and the bacterial cell membrane (for silver). Using a Caenorhabditis elegans animal model we showed silver-tellurite has reduced toxicity over individual metal/metalloid salts and provides increased antioxidant properties to the host. This work demonstrates that the addition of tellurite would improve the efficacy of silver in biomedical applications. IMPORTANCE Metals and/or metalloids could represent antimicrobial alternatives for industrial and clinical applications (e.g., surface coatings, livestock, and topical infection control) because of their great properties, such as good stability and long half-life. Silver is the most common antimicrobial metal, but resistance prevalence is high, and it can be toxic to the host above a certain concentration. We found that a silver-tellurite composition has antibacterial synergistic effect and that the combination is beneficial to the host. So, the efficacy and application of silver could increase by adding tellurite in the recommended concentration(s). We used different methods to evaluate the mechanism for how this combination can be so incredibly synergistic, leading to efficacy against antibiotic- and silver-resistant isolates. Our two main findings are that (i) both silver and tellurite mostly target the same pathways and (ii) the coapplication of silver with tellurite tends not to target new pathways but targets the same pathways with an amplified change.
| S-EPMC10433965 | biostudies-literature
Project description:Applications for silver nanomaterials in consumer products are rapidly expanding, creating an urgent need for toxicological examination of the exposure potential and ecological effects of silver nanoparticles (AgNPs). The integration of genomic techniques into environmental toxicology has presented new avenues to develop exposure biomarkers and investigate the mode of toxicity of novel chemicals. In the present study we used a 15k oligonucleotide microarray for Daphnia magna, a freshwater crustacean and common indicator species for toxicity, to differentiate between particle specific and ionic silver toxicity and to develop exposure biomarkers for citrate-coated and PVP-coated AgNPs. Gene expression profiles revealed that AgNO3 and AgNPs have distinct expression profiles suggesting different modes of toxicity. However, the gene expression profiles of the different coated AgNPs were similar revealing similarities in the cellular effects of these two particles. Major biological processes disrupted by the AgNPs include protein metabolism and signal transduction. In contrast, AgNO3 caused a downregulation of developmental processes, particularly in sensory development. Metal responsive and DNA damage repair genes were induced by the PVP AgNPs, but not the other treatments. In addition, two specific biomarkers were developed for the environmental detection of PVP AgNPs; although further verification under different environmental conditions is needed. We exposed Daphnia magna to the 1/10 LC50 and LC25 of citrate coated and PVP-coated Ag nanoparticles and Ag+ as AgNO3 for 24-h. For each exposure condition, we performed 6 replicate exposures with 5 individuals in each. All exposures were compared to a unexposed laboratory control.
2012-08-04 | E-GEOD-35150 | biostudies-arrayexpress
Project description:Transcriptional profiling comparing Escherichia coli simultaneously exposed to tellurite and CTX with untreated control cells; Tellurite with control; CTX with control Three-condition experiment, antibacterial (tellurite; CTX or tellurite/CTX) vs. Untreated control cells. Biological replicates: 3 control, 3 toxicants exposed cells, independently grown and harvested. One replicate per array.
2013-09-01 | E-GEOD-39696 | biostudies-arrayexpress
Project description:Purpose: We use the ribosome profiling protocol to understand why EF4 confers resistance to tellurite and how tellurite affects ribosome. Methods: We used ribosome profiling and transcriptomic data to analyze mainly by plastid software. The ribosome were purified by sucrose gradient separation. Results: Using polysome profile and sequencing data, we found that tellurite disables the ribosome subunits to form a functional 70S ribosome and reduces the ribosome density after tellurite exposure. We also found that tellurite influences the ribosome reaching to stop codon. Tellurite shortened the ribosome protected fragment, this process was mediated by EF4. EF4 mediated more gene expression including these known tellurite resistance genes to confer tellurite resistance. Tellurite also induced many differential gene expression. Conclusions: Tellurite exerts its toxicity on ribosome by disabling 70S ribosome formation, reaching to stop codon, and inducing differential gene expression.
2021-01-29 | GSE109907 | GEO
Project description:Background: The uncontrolled and widespread use of (nano)silver compounds has led to the increased release of these compounds into the environment, raising concerns about their negative impact on ecosystems. Concomitantly, silver resistance determinants are widely spread among environmental and clinically relevant bacteria although the underlying mechanisms are not yet fully understood. Results: In this study, we show that Cupriavidus metallidurans is able to adapt to toxic silver concentrations and explicate the genetic circuit responsible for this adaptation. None of the known silver resistant determinants present in C. metallidurans are involved in the adapted response. Instead, increased silver resistance is achieved by the concerted action of a two-component system AgrR-AgrS, previously not associated with metal resistance, and two intrinsically disordered proteins PrsQ1 and PrsQ2. Both belong to an unique group of small, uncharacterized, extracellular proteins restricted to the genera Cupriavidus and Ralstonia. This system seems to be much more efficient as it gives C. metallidurans the ability to withstand much higher silver concentrations. The latter could be facilitated by the accumulation of silver ions and the formation of silver nanoparticles. Conclusions: Detailed knowledge and exploitation of this protein family could result in novel routes for metal nanoparticle formation and metal processing relevant for biotechnical and biomedical applications.
2018-12-31 | GSE107669 | GEO
Project description:The toxicity of silver and zinc oxide nanoparticles is hypothesised to be mediated by dissolved metal ions and cerium dioxide nanoparticles (CeO2 NPs) are hypothesised to induce toxicity specifically by oxidative stress dependant on their surface redox state. To test these hypotheses, RNAseq was applied to characterise the molecular responses of cells to metal nanoparticle and metal ion exposures. The human epithelial lung carcinoma cell line A549 was exposed to different CeO2 NPs with different surface charges, micron-sized and nano-sized silver particles and silver ions, micron-sized and nano-sized zinc oxide particles and zinc ions, or control conditions, for 1 hour, 6 hours and 24 hours. Concentrations were the lower of either EC20 or 128 micrograms/mL. Transcriptional responses were characterised by RNAseq transcriptomics using an Illumina HiSeq2500 .
2018-02-01 | E-MTAB-5734 | biostudies-arrayexpress
Project description:Purpose: Analyze changes in the transcriptome of Arabidopsis thaliana in response to chronic exposure to silver nitrate at 4 μg/mL concentration. Methods: mRNA was extracted from non-treated and silver nitrate-treated 14-day old Arabidopsis thaliana seedlings using the RNAeasy extraction kit (Qiagen). RNA-seq libraries (3 rep/treatment and 3 reps/control) constructed with the TruSeq Stranded mRNA Sample Preparation kit (Illumina) were paired-end sequenced (100-nt read length) on an Illumina Nova Seq6000 system. Reads were mapped to the A. thaliana TAIR10 reference genome sequence and transcript levels were analyzed using the softare CLC Genomics Workbench (version 20.0.4, Qiagen). Results: Chronic exposure of A. thaliana plants to silver nitrate caused a change in the abundance of transcripts: AT2G01520 and AT4G12550, but no measureable impact on the rest of the transcriptome. Conclusions: Exposure of A. thaliana to silver nitrate at 4 μg/mL has minor impact on the transcriptome.
2022-03-15 | GSE198360 | GEO
Project description:Effects of silver nanoparticles (Ag NPs) on freshwater species have been reported in several studies, but there is not information on the potential long-term consequences of a previous exposure. In this work, we investigated the long-term effects of maltose-coated Ag NPs (20 nm) and of ionic silver (10 µg/L) after 21 days of exposure and at 6 months post-exposure (mpe) in adult zebrafish. Exposure resulted in significant silver accumulation in the whole body of fish exposed to ionic silver, but not in those exposed to Ag NPs. However, autometallography revealed metal accumulation in the liver and intestine of fish treated with the two silver forms and especially in the intestine of fish exposed to Ag NPs. X-ray microanalysis showed the presence of silver in gills, liver and intestine and of Ag NPs in gill and liver cells. Inflammation and hyperplasia were evident in the gills after both treatments and these histopathological conditions remained at 6 mpe. According to the hepatic transcriptome analysis, at 3 days ionic silver regulated a larger number of transcripts (410) than Ag NPs (129), while at 21 days Ag NPs provoked a stronger effect (799 vs 165 regulated sequences). Gene ontology terms such as “metabolic processes” and “response to stimulus” appeared enriched after all treatments, while “immune system” or “reproductive processes” were specifically enriched after the exposure to Ag NPs. This suggests that the toxicity of Ag NPs may not be solely related to the release of Ag ions, but also to the NP form. No evident effects were found on protein oxidation or on hepatocyte lysosomal membrane stability during exposure, but effects recorded on liver lysosomes and persistent damage on gill tissue at 6 mpe could indicate potential for long-term effects in exposed fish.
2018-06-12 | GSE89653 | GEO