AgNP Treatment Research Articles

Silver nanoparticles induced apoptosis in papillary and follicular thyroid carcinoma cells

Uniform and Monodisperse AgNPs were synthesized via a simple chemical reduction approach the synthesized AgNPs' characterizations were as follows: UV–Vis analysis displayed Surface plasmon resonance (SPR) of AgNPs peaked around 425 nm. AgNPs were shown to have a crystalline structure with a face-centered cubic (FCC) lattice using X-ray diffraction (XRD) investigation. Transmission electron microscopy (TEM) images illustrated a spherical in shape and well dispersant AgNPs, having a 12 nm average size. The AgNPs' stability was confirmed by dynamic light scattering (DLS) data with the coincidence of hydrodynamic diameter to the nominal particle size obtained from TEM. Interestingly, the synthesized AgNPs demonstrated a dose-dependent reduction of thyroid carcinoma growth, the Papillary (MDA-T22) and the Follicular (FTC-133) cells with determined IC50 values of 71.35 and 52.79 μg/ml, respectively. Meanwhile, against normal cells (WRL-68) the AgNPs had no cytotoxic effect at low concentrations and minimal cytotoxicity at higher of 200–400 μg/ml with a significantly increased IC50 value reached to 218.4 μg ml−1. The induced apoptosis of AgNPs treated cancer cells was determined by a High-content screening (HCS) assay. Moreover, the apoptotic morphological changes were explored and the mechanism of affected living cells to apoptosis showed an increase in cell membrane permeability, cytochrome c level, and nuclear intensity in dose-dependent with a significant deferent at higher concentrations (100 and 200 μg mL−1) (p < 0.0001). Conversely, a noticeable decrease in cell viable count and mitochondrial membrane permeability was observed with AgNPs treatment compared with control. Our findings indicate the potential suitability of these nanoparticles for biological and clinical applications.

Beneficial effects of Spirulina platensis on mice testis damaged by silver nanoparticles.

Silver nanoparticles (AgNPs) have been used widely in medical applications and various industries. Humans could be exposed to the risk of AgNPs toxicity through different routes. The current study aimed to investigate the role of Spirulina platensis (SP) against the side effects of AgNPs on mice testis. Adult male NMRI mice were divided into four groups: control group, SP group (300 mg/kg bwt), AgNPs (20 nm) group (500 mg/kg bwt), Co-treated group (SP + AgNPs). The groups were treated orally for 35 days. Subsequently, epididymal sperm parameters, sperm DNA integrity, daily sperm production (DSP), sexual hormones level, malondialdehyde (MDA), total antioxidant capacity (TAC) and spermatogenesis indices were measured. In addition, the histopathology of testes was evaluated using tissue processing, haematoxylin-eosin staining and stereology techniques. A significant decrease in the number of spermatogenic cells, Leydig cells and sperm parameters was observed in the AgNPs treated group. Serum levels of testosterone and TAC were decreased significantly following AgNPs treatment. Also, MDA incremented in the serum of AgNPs treated mice. The stereological analysis revealed that AgNPs exposure induced histopathological changes in the seminiferous tubules, degeneration and dissociation of spermatogenic cells. In contrast, SP co-administration significantly counteracted AgNPs reproductive toxicity impacts. SP co-exposure caused an increase in spermatogenesis indices, TAC and also a decrease in MDA. SP improved the histopathological changes of testes tissue and spermatozoa abnormalities. In parallel, SP modulated levels of testosterone, FSH and LH. Spirulina platensis exhibited the protective potential by regulating oxidative stress against AgNPs-induced reproductive toxicity. SP could be a candidate therapy against AgNPs reprotoxic impacts.

Preservation of Litchi Fruit with Nanosilver Composite Particles (Ag-NP) and Resistance against Peronophythora litchi.

Litchi (Litchi chinensis Sonn.) is susceptible to infection by Peronophythora litchi post storage, which rapidly decreases the sensory and nutritional quality of the fruit. In this study, the effects of nanosilver (Ag-NP) solution treatment on the shelf life of litchi fruit and the inhibition of P. litchi were examined, and the underlying mechanisms were discussed. For investigations, we used one variety of litchi (‘Feizixiao’), dipping it in different concentrations of Ag-NP solution after harvesting. Meanwhile, we treated P. litchi with different concentrations of Ag-NP solution. According to the data analysis, litchi treated with 400 μg/mL Ag-NPs and stored at 4 °C had the highest health rate and the lowest browning index among all the samples. In the same trend, treatment with 400 μg/mL Ag-NPs produced the best results for anthocyanin content, total soluble solids content, and titratable acidity content. Additionally, according to the results of the inhibition test, 800 μg/mL Ag-NP solution had a 94.97% inhibition rate against P. litchi. Within 2–10 h following exposure to 400 μg/mL Ag-NP solution, the contents of superoxide dismutase, peroxidase, and catalase in P. litchi gradually increased and peaked, followed by a gradual decline. At this time, the integrity of the cell membrane of P. litchi could be broken by Ag-NP solution, and the sporangia showed deformed germ tubes and abnormal shapes. Taken together, these results suggested that Ag-NP treatment inhibited respiration and P. litchi activity, which might attenuate litchi pericarp browning and prolong the shelf life of litchi. Accordingly, Ag-NPs could be used as an effective antistaling agent in litchi fruit and as an ecofriendly fungicide for the post-harvest control of litchi downy blight. This study provides new insights into the application of Ag-NP as an antistaling agent for fruit storage and as an ecofriendly fungicide.

Silver and copper-oxide nanoparticles prepared with GA3 induced defense in rice plants and caused mortalities to the brown planthopper, Nilaparvata lugens (Stål)

BackgroundNanoparticles have been employed as nanopesticides for pest control in agriculture. However, the harmful effects of their chemical synthesis on human and environmental health have resulted in increased use of green synthetic approaches, including the use of plant extracts. The brown planthopper, Nilaparvata lugens (Stål) (BPH), is a severe pest of rice plants (Oryza sativa L.), especially in Asia. It is usually controlled chemically but has developed resistance against many insecticides. ResultsIn this study, we synthesized metallic silver (Ag-NPs) and copper-oxide (CuO-NPs) nanoparticles using the exogenous phytohormone, gibberellic acid (GA3), as a reducing agent. We then sprayed them separately on rice plants and BPH together and evaluated their effects on the plants and insects. SEM and TEM images showed that the synthesis was successful, indicated by the sizes (25–60 nm), uniform shape and spherical and cubical structures of Ag-NPs, as well as by the rugby sheet-like of CuO-NPs with lateral sizes of 150–340 nm and thickness of 30–70 nm. Independent applications of the nanoparticles and GA3 on rice plants induced different volatile profiles, of which the highest number emitted was under Ag-NPs, including the highest emission of linalool. Transcriptome analysis showed that Ag-NPs-treated rice plants showed different transcriptome profiles compared to the control, 24 h after treatment, including the upregulation of the linalool synthase gene, genes of plants transcription factors such as WRKY, bHLH and NAC and other genes involved in plant defense responses. In all treatments, the mortality rate of BPH increased with an increase in NPs concentrations over time but was prominent under Ag-NPs treatment. The LC50 values for Ag-NPs and CuO-NPs decreased with an increase in time. Also, the nanoparticles increased the activities of protective enzymes (POD, SOD and CAT), inhibited that of detoxification enzymes (A-CHE, ACP and AKP), and reduced total protein concentrations in the BPH. ConclusionsThese results show that synthesizing nanoparticles using phytohormones may be a safer and environmentally friendly option, which also holds promise for controlling the BPH in rice production.

Green silver nanoparticles against Helicoverpa armigera and its effects on biochemical, morphological and histological aspects

The aim of this study was to evaluate the effect of green synthesized silver nanoparticles using aqueous leaf extract of Ricinus communis (castor plant) on the life cycle Helicoverpa armigera. The synthesized AgNPs were identified using different microscopic techniques: UV-Visible spectroscopy, Scanning electron microscopy (SEM), Energy-disruptive X-ray spectroscopy (EDX) and Transmission electron microscopy (TEM). Insecticidal activity of AgNPs was studied using leaf dipping method. The biochemical studies were analyzed at LC50 of AgNPs using different methods (total carbohydrate using phenol-sulphuric acid reaction of Dubois method, total protein using Bradford method, total lipid using sulfo-phospho vanillin of Knight method and non-specific esterases using Van-Asperan method, respectively). UV-vis spectrophotometer confirmed the spectra at 445 nm of AgNPs. Spherical shaped AgNPs of 8.96 nm size were confirmed by TEM and SEM. EDX spectra confirm the chemical composition AgNPs. Higher mortality was observed in 6th instar larvae (70-80% at LC50 175 ppm) than the other instars. The pupa and adult of H. armigera also exhibited toxicity against the AgNPs. Effect of AgNPs treatment was investigated on the midgut of 5th instar larva of H. armigera using the transmission electron microscope. Accumulation of AgNPs in cell organelles was confirmed by ultra structural studies of insect midgut cell using TEM. The biochemical components of 5th instar larvae showed that, the amount of total carbohydrate, total protein, total lipid and non-specific esterases were significantly decreased After 24 h treatment at LC50 of AgNPs. Now, we can summarise that, synthesis of AgNPs using R. communis is a green route to control pest population. The synthesized nanoparticles could be used for the improvement of new botanical nano-insecticide or nano-formulation after successful field trials.

The antifungal activity and mechanism of silver nanoparticles against four pathogens causing kiwifruit post-harvest rot.

Post-harvest rot causes enormous economic loss to the global kiwifruit industry. Currently, there are no effective fungicides to combat the disease. It is unclear whether silver nanoparticles (AgNPs) are effective in controlling post-harvest rot and, if so, what the underlying antifungal mechanism is. Our results indicated that 75 ppm AgNPs effectively inhibited the mycelial growth and spore germination of four kiwifruit rot pathogens: Alternaria alternata, Pestalotiopsis microspora, Diaporthe actinidiae, and Botryosphaeria dothidea. Additionally, AgNPs increased the permeability of mycelium’s cell membrane, indicating the leakage of intracellular substance. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations revealed that AgNPs induced pathogen hypha shrinkage and distortion, as well as vacuolation in hypha cells, implying that AgNPs caused cellular and organelle structural degradation. The transcriptome sequencing of mycelium treated with AgNPs (24 h / 48 h) was performed on the Illumina Hiseq 4000 sequencing (RNA-Seq) platform. For the time points of 24 h and 48 h, AgNPs treatment resulted in 1,178 and 1,461 differentially expressed genes (DEGs) of A. alternata, 517 and 91 DEGs of P. microspora, 1,287 and 65 DEGs of D. actinidiae, 239 and 55 DEGs of B. dothidea, respectively. The DEGs were found to be involved in “catalytic activity,” “small molecule binding,” “metal ion binding,” “transporter activity,” “cellular component organization,” “protein metabolic process,” “carbohydrate metabolic process,” and “establishment of localization.” Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis also revealed that “carbohydrate metabolism,” “amino acid metabolism,” “energy metabolism,” and “xenobiotics biodegradation and metabolism” of “metabolism processes” were the most highly enriched pathways for these DEGs in four pathogens, with “cellular processes” being particularly enriched for B. dothidea. Furthermore, quantitative polymerase chain reactions (qPCRs) were used to validate the RNA-seq results. It was also confirmed that AgNPs could significantly reduce the symptoms of kiwifruit rot without leaving any Ag+ residue on the peel and flesh of kiwifruit. Our findings contributed to a better understanding of the antifungal effect and molecular mechanisms of AgNPs against pathogens causing kiwifruit post-harvest rot, as well as a new perspective on the application of this novel antifungal alternative to fruit disease control.

Silver nanoparticles induce developmental toxicity via oxidative stress and mitochondrial dysfunction in zebrafish (Danio rerio)

Sliver nanoparticles (AgNPs) are widely used in industry, agriculture, and medicine, potentially resulting in adverse effects on human health and aquatic environments. Here, we investigated the developmental toxicity of zebrafish embryos with acute exposure to AgNPs. Our results demonstrated developmental defects in 4 hpf zebrafish embryos after exposure to different concentrations of AgNPs for 72 h. In addition, RNA-seq profiling of zebrafish embryos after AgNPs treatment. Further Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses showed that the differentially expressed genes (DEGs) were enriched in DNA replication initiation, oxidoreductase activity, DNA replication, cellular senescence, and oxidative phosphorylation signaling pathways in the AgNPs-treated group. Notably, we also found that AgNPs exposure could result in the accumulation of reactive oxygen species (ROS) and malondialdehyde (MDA), the inhibition of superoxide dismutase (SOD), catalase (CAT), and mitochondrial complex I-V activities, and the downregulated expression of SOD, CAT, and mitochondrial complex I-IV chain-related genes. Moreover, the expression of mitochondrion-mediated apoptosis signaling pathway-related genes, such as bax, bcl2, caspase-3, and caspase-9, was significantly regulated after AgNPs exposure in zebrafish. Therefore, these findings demonstrated that AgNPs exposure could cause oxidative stress, induce mitochondrial dysfunction, and ultimately lead to developmental toxicity.

Effect of Silver Nanoparticles on the In Vitro Regeneration, Biochemical, Genetic, and Phenotype Variation in Adventitious Shoots Produced from Leaf Explants in Chrysanthemum.

Novel and unique properties of nanomaterials, which are not apparent in larger-size forms of the same material, encourage the undertaking of studies exploring the multifaced effects of nanomaterials on plants. The results of such studies are not only scientifically relevant but, additionally, can be implemented to plant production and/or breeding. This study aimed to verify the applicability of silver nanoparticles (AgNPs) as a mutagen in chrysanthemum breeding. Chrysanthemum × grandiflorum (Ramat.) Kitam. ‘Lilac Wonder’ and ‘Richmond’ leaf explants were cultured on the modified MS medium supplemented with 0.6 mg·L−1 6-benzylaminopurine (BAP) and 2 mg·L−1 indole-3-acetic acid (IAA) and treated with AgNPs (spherical; 20 nm in diameter size; 0, 50, and 100 mg·L−1). AgNPs strongly suppressed the capability of leaf explants to form adventitious shoots and the efficiency of shoot regeneration. The content of primary and secondary metabolites (chlorophyll a, chlorophyll b, total chlorophylls, carotenoids, anthocyanins, phenolic compounds) and the activity of enzymatic antioxidants (superoxide dismutase and guaiacol peroxide) in leaf explants varied depending on the AgNPs treatment and age of culture. Phenotype variations of ex vitro cultivated chrysanthemums, covering the color and pigment content in the inflorescence, were detected in one 50 mg·L−1 AgNPs-derived and five 100 mg·L−1 AgNPs-derived ‘Lilac Wonder’ plants and were manifested as the color change from pink to burgundy-gold. However, no changes in inflorescence color/shape were found among AgNPs-treated ‘Richmond’ chrysanthemums. On the other hand, the stem height, number of leaves, and chlorophyll content in leaves varied depending on the AgNPs treatment and the cultivar analyzed. A significant effect of AgNPs on the genetic variation occurrence was found. A nearly two-fold higher share of polymorphic products, in both cultivars studied, was generated by RAPD markers than by SCoTs. To conclude, protocols using leaf explant treatment with AgNPs can be used as a novel breeding technique in chrysanthemum. However, the individual cultivars may differ in biochemical response, the efficiency of in vitro regeneration, genetic variation, and frequency of induced mutations in flowering plants.

AgNPs Aggravated Hepatic Steatosis, Inflammation, Oxidative Stress, and Epigenetic Changes in Mice With NAFLD Induced by HFD.

The recent development of silver nanoparticles (AgNPs) has sparked increased interest in biomedical and pharmaceutical applications, leading to the possibility of human exposure. The liver is the primary target organ in the metabolism and transport of nanoparticles. Non-alcoholic fatty liver disease (NAFLD) is the most common and leading cause of hepatic metabolic syndrome with approximately 15% of patients will develop into non-alcoholic steatohepatitis, fibrosis, cirrhosis, and eventually hepatocellular carcinoma. Thus, the potential hepatotoxicity of AgNPs on NAFLD development and progression should be of great concern. Herein, we explored the potential hepatic effect of a single intravenously injected dose of 0.5, 2.5, and 12.5 mg/kg BW on the liver function of high-fat-diet (HFD)-fed mice for 7 days. AgNP treatment increased serum levels of alanine aminotransferase, aspartate transaminase, triglycerides and cholesterols, the number of lipid droplets, and the contents of triglycerides and cholesterols in NAFLD mice livers compared to HFD-fed mice. The mechanism of AgNP-induced worsen hepatotoxicity in mice is associated with hyperactivation of SREBP-1c-mediated de novo lipogenesis and liver inflammation. Additionally, HFD-fed mice treated with AgNPs had significantly higher oxidative damage and lower global DNA methylation and DNA hydroxymethylation than NAFLD mice. This study suggests that AgNP treatment exacerbated HFD-induced hepatic steatosis, liver inflammation, oxidative stress, and epigenetic changes in mice, which is relevant to the risk of AgNP exposure on NAFLD development and progression.

Low Concentrations of Silver Nanoparticles Inhibit Spore Germination and Disturb Gender Differentiation of Ceratopteris thalictroides (L.) Brongn

Because of their excellent antibacterial properties, silver nanoparticles (AgNPs) are widely used in all walks of life, which has caused them to be discharged into aquatic environments with possible negative effects on aquatic plants. In the present study, we used an aquatic fern, Ceratopteris thalictroides, as a model to investigate the effects of AgNPs on its spore germination, gametophytes, sex differentiation, and growth. The results demonstrated that AgNPs significantly inhibited spore germination of C. thalictroides at a AgNP concentration higher than 0.02 mg/L. Additionally, we found sex-dependent effects of AgNPs on the development and growth of the gametophyte of C. thalictroides. The proportion of hermaphrodites in the gametophytes and the area of gametophytes significantly decreased under AgNP treatment, while no significant effect was observed in the male gametophytes. Using the AgNP filtrate (without nanoparticles) and AgNPs plus cysteine (Ag+ chelator), we found that the release of Ag+ from nanoparticles was not the cause of the toxicity of AgNPs on C. thalictroides. The EC50 of AgNPs on spore germination was 0.0492 mg/L, thus indicating an ecological risk of AgNPs on this species even at concentrations lower than the Ag element concentration of the WHO guidelines for drinking-water quality.

Antibacterial and Antibiofilm Activity of Carboxymethyl Cellulose Stabilized Silver Nanoparticles Synthesized using Quercetin and Their Effects on Soil Respiration and Enzymes

Silver nanoparticles (AgNPs) were synthesized using quercetin in aqueous carboxymethyl cellulose (CMC) solution, which is used as both the reducing and capping bioagents in the current study. The characterization of synthesized CMC-Q AgNPs was performed through different analysis techniques. Antibacterial activity was assessed by using agar well diffusion assay against both gram-positive and gram-negative strains. Also, the effect of nanoparticles on biofilm formation of Staphylococcus aureus was investigated. Moreover, soil treated with CMC-Q AgNPs and AgNO3 was analyzed in terms of soil respiration, silver contents, and soil exoenzymes (dehydrogenase and urease). In the study, the microscopic images represented the average size of the CMC-Q AgNPsto be 27 nm and the zeta potential of −59.4 (mV) could also be signed as the higher stability. Generally, the results indicate that CMC-Q AgNPs might be powerful antibacterial agents. Furthermore, we found that CMC-Q AgNPs and AgNO3 could both inhibit exoenzyme activities in soil, with the inhibitory effects especially obvious at higher exposure times and concentrations. Also, the findings revealed that Ag concentration and soil respiration (% of control) in the soil treated with AgNO3 was lower compared to CMC-Q AgNPs treatment. This might be explained in terms of different transformations of two compounds in the soil.

Short-term exposure to silver nano-particles alters the physiology and induces stress-related gene expression in Nelumbo nucifera

Lotus (Nelumbo nucifera) was used as model plant in this study to explore its physiology and molecular response upon short-term exposure to silver nano-particles (AgNPs). Accumulation patterns demonstrated a potential uptake of AgNPs by roots and transport to the leaves as a likely key translocation route in lotus. AgNPs exposure was negatively correlated with lotus growth, including germination rate and petiole length in a concentration-dependent manner. Synthesis of chloroplast pigments in lotus leaves was enhanced by low AgNPs concentration, but were inhibited at high concentration. Hydrogen peroxide (H2O2) was detected in lotus leaves after AgNPs treatment. Proline accumulation in lotus leaves was induced with the increase in AgNPs concentration and exposure time. Antioxidant enzyme activities of superoxide dismutase (SOD), peroxidase (POD) as well as catalase (CAT) were enhanced after the first day of AgNPs exposure, but declined with increased exposure time, indicating a time-dependent toxicity of AgNPs. In addition, real-time PCR revealed that two detoxification-related genes, GSH1 and GST, could be activated on the first day of AgNPs exposure, but down-regulated with prolonged AgNPs treatment. Photosynthesis-related RbcS gene was up-regulated, however, no obvious difference in the expression of RbcL was observed after the first day of AgNPs exposure. Moreover, WRKY70a and WRKY70b transcription factors exhibited similar expression patterns, with the highest induction after a 5 mg/L AgNPs exposure on the first day, which decreased with prolonged exposure time. This study provides useful references for further evaluation of the toxic mechanism of AgNPs and their bio-effects on aquatic plants and ecosystems.

Mechanism of Phanerochaete chrysosporium-mediated tetracycline hydrochloride removal promoted by low-dose silver nanoparticles

The influence of silver nanoparticles (AgNPs) on environmental microorganisms has been extensively reported, however, there is currently limited understanding of effects of stress-induced by AgNPs on other pollutant degradation. In this study, Phanerochaete chrysosporium was stimulated by different concentrations of AgNPs to explore its effect on P. chrysosporium-mediated degradation of tetracycline hydrochloride (TCH). The results indicate that treatment with AgNPs at low concentration resulted in a considerable increase in TCH degradation, TCH degradation reached a maximum of 97% with 0.1 mg L−1 AgNPs treated after 3 d, and the viability of P. chrysosporium increased 1.48 times compared with the control group. The largest O2 influx of − 17 pmol cm−2 s−1 under 0.1 mg L−1 AgNPs treatment reveal the enhancement of P. chrysosporium respiration. In addition, low concentrations of AgNPs could induce the overexpression of cytochrome P450 and extracellular degradation enzymes MnP-related genes in stimulated cells, which further induce the production of extracellular degrading enzymes (51.0 U L−1 MnP and 23.7 U L−1 LiP) to accelerate the degradation of TCH. Together, our combined results uncovered the enhanced degradation mechanisms of P. chrysosporium induced by which AgNPs under sublethal dosage.

Silver Nanoparticles Alter Microtubule Arrangement, Dynamics and Stress Phytohormone Levels.

The superior properties of silver nanoparticles (AgNPs) has resulted in their broad utilization worldwide, but also the risk of irreversible environment infestation. The plant cuticle and cell wall can trap a large part of the nanoparticles and thus protect the internal cell structures, where the cytoskeleton, for example, reacts very quickly to the threat, and defense signaling is subsequently triggered. We therefore used not only wild-type Arabidopsis seedlings, but also the glabra 1 mutant, which has a different composition of the cuticle. Both lines had GFP-labeled microtubules (MTs), allowing us to observe their arrangement. To quantify MT dynamics, we developed a new microscopic method based on the FRAP technique. The number and growth rate of MTs decreased significantly after AgNPs, similarly in both lines. However, the layer above the plasma membrane thickened significantly in wild-type plants. The levels of three major stress phytohormone derivatives—jasmonic, abscisic, and salicylic acids—after AgNP (with concomitant Ag+) treatment increased significantly (particularly in mutant plants) and to some extent resembled the plant response after mechanical stress. The profile of phytohormones helped us to estimate the mechanism of response to AgNPs and also to understand the broader physiological context of the observed changes in MT structure and dynamics.

The individual and combined effects of polystyrene and silver nanoparticles on nitrogen transformation and bacterial communities in an agricultural soil

The effects of emerging contaminants micro/nanoplastics (MPs/NPs) and silver nanoparticles (Ag NPs) on health have attracted universal concern throughout the world. However, it is unclear on the combined effects of MPs/NPs and Ag NPs on the biogeochemistry cycle such as nitrogen transformation and functional microorganism in the soil. In the present study, we conducted a 45-day soil microcosm experiment with polystyrene (PS) MPs/NPs and Ag NPs to investigate their combined impact on nitrogen cycling and the bacterial community. The results showed that MPs or NPs exerted limited effects on nitrogen transformation in the soil. The combined effects of PS MPs/NPs and Ag NPs were mainly caused by the presence of Ag NPs. However, PS NPs alleviated the inhibition of anammox and denitrification induced by Ag NPs via upregulating anammox-related genes and elevating nitrate and nitrite reductase activities. PS MPs + Ag NPs treatment significantly reduced bacterial diversity. PS MPs/NPs + Ag NPs increased the relative abundances of denitrifying Cupriavidus by 0.32% and 0.06% but decreased nitrogen-fixing functional microorganisms of Microvirga (by 2.05% and 2.24%), Bacillus (by 0.16% and 0.22%), and Herbaspirillum (by 0.14% and 0.07%) at the genus level compared with Ag NPs alone. The significant downregulation of nitrogen-fixing genes (K02586, K02588, and K02591) was observed in PS MPs/NPs + Ag NPs treatment compared to Ag NPs in the nitrogen metabolism pathway. Moreover, g-Lysobacter and g-Aquimonas were identified as biomarkers in PS MPs + Ag NPs and PS NPs + Ag NPs by LEfSe analysis. Our study sheds the light that changes of functional microorganism abundances contributed to the alteration of nitrogen transformation. Taking the particle size of plastics into account will be helpful to accurately assess the combined ecological risks of plastics and nanomaterial contaminants.

Green Synthesis of Silver Nanoparticles by the Cyanobacteria Synechocystis sp.: Characterization, Antimicrobial and Diabetic Wound-Healing Actions.

Green nanotechnology is now accepted as an environmentally friendly and cost-effective advance with various biomedical applications. The cyanobacterium Synechocystis sp. is a unicellular spherical cyanobacterium with photo- and hetero-trophic capabilities. This study investigates the ability of this cyanobacterial species to produce silver nanoparticles (AgNPs) and the wound-healing properties of the produced nanoparticles in diabetic animals. Methods: UV–visible and FT-IR spectroscopy and and electron microscopy techniques investigated AgNPs’ producibility by Synechocystis sp. when supplemented with silver ion source. The produced AgNPs were evaluated for their antimicrobial, anti-oxidative, anti-inflammatory, and diabetic wound healing along with their angiogenesis potential. Results: The cyanobacterium biosynthesized spherical AgNPs with a diameter range of 10 to 35 nm. The produced AgNPs exhibited wound-healing properties verified with increased contraction percentage, tensile strength and hydroxyproline level in incision diabetic wounded animals. AgNPs treatment decreased epithelialization period, amplified the wound closure percentage, and elevated collagen, hydroxyproline and hexosamine contents, which improved angiogenesis factors’ contents (HIF-1α, TGF-β1 and VEGF) in excision wound models. AgNPs intensified catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx) activities, and glutathione (GSH) and nitric oxide content and reduced malondialdehyde (MDA) level. IL-1β, IL-6, TNF-α, and NF-κB (the inflammatory mediators) were decreased with AgNPs’ topical application. Conclusion: Biosynthesized AgNPs via Synechocystis sp. exhibited antimicrobial, anti-oxidative, anti-inflammatory, and angiogenesis promoting effects in diabetic wounded animals.

AgNPs reduce reproductive capability of female mouse for their toxic effects on mouse early embryo development.

Silver nanoparticles (AgNPs) are widely applied in the field of personal protection for their powerful toxic effects on cells, and recently, a new type of vaginal gel with AgNPs is used to protect the female reproductive tract from microbes and viruses. However, a high risk of AgNPs to the fetus and the underlying mechanism of AgNPs to interfere in embryo development still remain unclear. Thus, this study investigated the impact of two drugs of vaginal gel with AgNPs on reproductive capability of the female mouse by animal experiment. Then, kinetics of AgNPs affecting embryo development was investigated by in vitro embryos culturing, and cell membrane potential (CMP) of zygotes was analyzed by DiBAC4(3) staining. Results indicated that one of the drugs of vaginal gel certainly injured embryo development in spite of no apparent histological change found in ovaries and uteruses of drug-treated mice. In vitro embryo culturing discovered that the toxic effect of AgNPs on embryo development presented particle sizes and dose dependent, and AgNP treatment could rapidly trigger depolarization of the cell membrane of zygotes. Moreover, AgNPs changed the gene expression pattern of Oct-4 and Cdx2 in blastocysts. All these findings suggest that AgNPs can interfere with normal cellular status including cell membrane potential, which has not been noticed in previous studies on the impact of AgNPs on mammalian embryos. Thus, findings of this study alarm us the risk of applying vaginal gel with AgNPs in individual caring and protection of the female reproductive system.

Responses of Allium cepa L. exposed to silver nanoparticles

The study was aimed to determine the gallic acid, rutin and quercetin contents and yield of Narli onion genotype (Allium cepa L.,) exposed to four different doses (0, 25, 50, 75, 100 mg L-1) of silver nanoparticles (AgNPs)for30 days, after planting the onion bulbs, attwo-week intervals. Quercetin, rutinand gallic acid contents in the leaves and bulbs of onion plants were determined.While the quercetin content was the highest in 25 mg L-1ofAgNPs treatment (575.0 ± 10.39 µg g-1)in the bulb parts, gallic acid content reachedtothe highest rate in 50 mg L-1 of AgNPs(3605.8 ± 90.96µg g-1), inthe onion bulb, compared to the control (2819.3 ± 65.72µg g-1).The content of rutinwere enhanced in 25 (19.72 ± 0.28µg g-1), 50 (21.66 ± 0.57µg g-1) and 75 mg L-1(31.08 ± 0.53 µg g-1) of AgNPs treatments, but it was significantly close to the control (7.15 ± 0.93µg g-1), in100 mg L-1(10.92 ± 0.38 µg g-1), in bulb parts.Chlorophyll content showed reducesin all doses, except for25 mg L-1 of AgNPs treatment. Total yield enhanced in treatments of AgNPs, but the highest increase was obtained in treatment of 50 mg L-1 of AgNPs (97.49 ± 0.92 µg g-1). The analysis of quercetin, rutin and gallic acid contents were performed by high performance liquid chromatography (HPLC), and Chlorophyll was determined by SPAD.

Experimental evolution of Pseudomonas putida under silver ion versus nanoparticle stress.

Whether the antibacterial properties of silver nanoparticles (AgNPs) are simply due to the release of silver ions (Ag+ ) or, additionally, nanoparticle-specific effects, is not clear. We used experimental evolution of the model environmental bacterium Pseudomonas putida to ask whether bacteria respond differently to Ag+ or AgNP treatment. We pre-evolved five cultures of strain KT2440 for 70 days without Ag to reduce confounding adaptations before dividing the fittest pre-evolved culture into five cultures each, evolving in the presence of low concentrations of Ag+ , well-defined AgNPs or Ag-free controls for a further 75 days. The mutations in the Ag+ or AgNP evolved populations displayed different patterns that were statistically significant. The non-synonymous mutations in AgNP-treated populations were mostly associated with cell surface proteins, including cytoskeletal membrane protein (FtsZ), membrane sensor and regulator (EnvZ and GacS) and periplasmic protein (PP_2758). In contrast, Ag+ treatment was selected for mutations linked to cytoplasmic proteins, including metal ion transporter (TauB) and those with metal-binding domains (ThiL and PP_2397). These results suggest the existence of AgNP-specific effects, either caused by sustained delivery of Ag+ from AgNP dissolution, more proximate delivery from cell-surface bound AgNPs, or by direct AgNP action on the cell's outer membrane.

Protective role of silver nanoparticles in influenza infection

BACKGROUND: The present study assesses copper metabolism of the host organism as a target of antiviral strategy, basing on the virocell concept. This concept suggests that the targets for suppressing viral reproduction can be found in the hosts metabolism.&#x0D; AIM: Evaluation of the effect of copper status indicators on influenza infection in mice.&#x0D; MATERIALS AND METHODS: Silver nanoparticles (AgNPs) were used as a specific active agent because they reduce the level of holo-ceruloplasmin, the main extracellular cuproenzyme. The mouse model of influenza virus A infection was used with two doses: 1 LD50 and 10 LD50. The following treatment regimens were used: mice were pretreated four days before infection and then every day during infection development until the end of the experiment (day 14).&#x0D; RESULTS: The mice treated with AgNPs demonstrated significantly lower mortality, the protection index reached 6070% at the end of the experiment, and mean lifespan was prolonged. In addition, the treatment of the animals with AgNPs resulted in normalization of the weight dynamics. Despite the amelioration of the infection, AgNPs treatment did not influence influenza virus replication.&#x0D; CONCLUSIONS: This study provides support for the view that silver nanoparticles could be used as protection against influenza.