Impact Of Silver Nanoparticles Research Articles

Impact of silver nanoparticles on secondary metabolite composition and toxicity in anise (Pimpinella anisum L.) callus culture

BackgroundThere are numerous challenges associated with producing desired amounts of secondary metabolites (SMs), which are mostly unique and cannot be chemically synthesized. Many studies indicate that nanoparticles (NPs) can boost the production of SMs. Still, the precise manner in which NPs induce metabolic changes remains unidentified. This study examines the influence of eco-friendly silver NPs (AgNPs) on the chemical makeup and toxicity of Pimpinella anisum L. (anise).ResultsAgNPs were introduced into anise callus cultures at different concentrations (0, 1.0, 5.0, 10, and 20 mg/L). The induced oxidative stress was tracked over intervals of 7, 14, 28, and 35 days. Chemical composition evaluations were carried out on the 35th day. Within the first 14 days, plant stress was evident, though the plant adapted to the stress later on. Notably, the plant showed high tolerance at 1 mg/L and 5 mg/L concentrations despite increased toxicity levels. However, relatively high toxicity levels were identified at 10 and 20 mg/L. The AgNP-induced stress significantly impacted anise SMs, particularly affecting fatty acid content. In the 10 and 20 mg/L AgNP groups, essential metabolites, including palmitic and linoleic acid, showed a significant increase. Polyunsaturated (omega) and monounsaturated fatty acids, vital for the food and pharmaceutical industries, saw substantial growth in the 1 and 5 mg/L AgNP groups. For the first time, vanillyl alcohol and 4-Hydroxybenzoic acid were detected along with various phenolic compounds, such as t-anethole, Salicylic acid, and Thiamazole.ConclusionAgNPs can function as an elicitor to efficiently generate essential SMs such as omegas and phenolic compounds in anise callus culture. This study explores the application of AgNPs as plant elicitors in anise SM production, offering invaluable insight into potential uses.

Impact of Silver Nanoparticles on Arbuscular Mycorrhizal Fungi and Glomalin-Related Soil Proteins in the Rhizosphere of Maize Seedlings

Glomalin-related soil protein (GRSP), an important arbuscular mycorrhizal (AM) fungal by-product, plays a key role in preserving or sequestrating soil organic carbon (C). Silver nanoparticles (AgNPs) have become an emerging contaminant and their impacts on soil ecosystems attract increasing concerns. The dynamics of AM fungi and GRSP could therefore form the basis for an in-depth exploration of the influences of AgNPs on soil ecosystems. This study investigated the effects of AgNPs on mycorrhizal growth and AM fungal communities, as well as the GRSP contents in maize (Zea mays L.) soils, with a pot experiment. The contributions of GRSP to soil organic C and the correlations of GRSP with soil organic C were also evaluated. The results indicated that AgNPs decreased the mycorrhizal colonization, AM fungal biomass, and diversity indices, and strongly shifted the community composition of AM fungi with a reduction in Acaulosporaceae and an enrichment in Glomeraceae. Additionally, AgNPs also decreased the soil’s easily extractable (EE) GRSP and total (T) GRSP contents, resulting in lower contributions of EE-GRSP-C and T-GRSP-C to the soil organic C. Linkage analyses revealed that AM fungal abundances have positive correlations with EE- and T-GRSP, and EE- and T-GRSP also positively correlated with soil organic C, indicating that the negative effects of AgNPs on AM fungal abundances and communities were extended to AM-fungal-associated C processes. Altogether, our study found that AgNPs decreased the AM fungal abundances shaped AM fungal communities, and reduced the soil GRSP content, which might subsequently be unfavorable for soil C storage.

Impact of silver nanoparticles (Ag-NPs) as a dietary supplement on growth performance, carcass traits, blood metabolites, digestive enzymes, and cecal microbiota of growing rabbits

Abstract The present study investigated the impact of silver nanoparticles (Ag-NPs) on growth performance, carcass traits, liver and kidney functions, immunity and antioxidant indicators, digestive enzymes, and cecum bacteriology of growing rabbits. 100 5-week-old New Zealand White (NZW) male rabbits were randomly divided into 5 equal groups and fed for 8 weeks on the basal diet only or on the basal diet supplemented with different levels of Ag-NPs (0.25, 0.50, 0.75, or 1.00 mg/kg diet). Animals in each group were randomly distributed in 10 cages (replicates), with two rabbits each. Different dietary concentrations of Ag-NPs significantly increased live body weight (LBW) and feed conversion ratio (FCR). Also, body weight gain (BWG) increased dramatically during all experimental periods except 11-13 weeks of age. Levels of 0.25 and 1 mg of Ag-NPs/kg diet showed the highest increase in LBW, BWG, and FCR. All studied carcass traits, except liver %, were not affected by Ag-NPs levels. Rabbits fed diet supplemented with 1 mg Ag-NPs had the highest liver %. Serum total protein, albumin, and globulin levels were increased (P<0.05) in groups treated with 0.25 and 0.75 mg Ag-NPs. In contrast, serum values of aspartate transaminase (AST) and alanine transaminase (ALT), urea and creatinine were significantly reduced with the supplementation of Ag-NPs up to 0.75 mg/kg diet. The immunoglobulins M, G, and A (IgM, IgG, and IgA), complement 3 (C3) and lysozyme activity were improved with the inclusion of nano-silver in the rabbit feeds, particularly at the level of 0.25 mg Ag-NPs/kg feed. The inclusion of Ag-NPs in rabbit diets at different concentrations increased the total antioxidant capacity and the activities of superoxide dismutase, catalase, and glutathione peroxidase. Growing rabbits fed on diets supplemented with Ag-NPs had higher levels of digestive enzymes than the control group. The addition of Ag-NPs reduced the load of E. coli, Salmonella spp. and Colioform in the rabbit cecum. Overall, the inclusion of 0.25–1 mg Ag-NPs/kg to NZW rabbit diets has shown beneficial effects on health and performance.

Impact of silver nanoparticles against stored product pest Sitophilus oryzae (L.) and effect on agromorphological characteristics of Zea mays (maize seeds)

The present study, comparative entomotoxic efficacy of silver nanoparticles obtained through the chemical and biological route against Sitophilus oryzae L. Physicochemical characterization results revealed that silver nanoparticles (Ag NPs) were spherical morphology with an average size of 20–51 nm having excellent stability. XRD diffraction peaks showed major peaks at (2 theta) 38.19º, 44.37º, 64.56º, and 77.47º confirming their crystalline nature. UV–vis spectra inferred strong absorbance between 410 and 450 nm. Bioassay studies exhibited the LD50 values as 40.16 mg/100 g for c-Ag NPs and 24.69 mg/100 g for b-Ag NPs. The mortality brought by b-Ag NPs at the dose of 130 mg after 6 days of exposure was 100% whereas only 80% of mortality was observed for c-Ag NPs at the same dose. These c-Ag NPs also enhanced seedling characteristics i.e., germination (96%), seedling length (45.33 cm), vigor index (4351.68), and dry matter production (4.20 g). The experiment results shows that the b-Ag NPs are an alternative to insecticides against S. oryzae and improving agromorphological characteristics of maize.

Silver and zinc oxide nanoparticles disrupt essential parasitism, neuropeptidergic, and expansion-like proteins genes in Meloidogyneincognita

Meloidogyne incognita leads to considerable losses in crop productivity. In this study, the impact of silver nanoparticles (AgNPs) and zinc oxide nanoparticles (ZnONPs) in 100, 200, or 300 ppm concentrations were investigated on some essential genes of M. incognita in vitro. For this purpose, AgNPs and ZnONPs were synthesized and characterized for their physicochemical properties. Thereafter, second-stage Juveniles (J2) of M. incognita were exposed to AgNPs and ZnONPs solution for 24 h. The LC50, LC90, and mortality rates were calculated for both nanoparticles. Finally, the expression of parasitism genes (Xyl-1; msp-20; 16D10), neuropeptidergic gene (Ace-2), expansion-like proteins (MAP-1), and oxidative stress gene (GSTS-1) was analyzed. The results showed a successful preparation of nanoparticles to obtain a pure, well-dispersed, and stable suspension, as revealed by physicochemical properties. ZnONPs showed LC50 and LC90 values of 63.56 and 208.5 ppm, respectively, while AgNPs recorded 11.78 and 28.59 ppm, respectively. AgNPs at concentrations 100, 200, and 300 ppm showed mortality rate 66%, 84%, and 100%, respectively, whereas ZnONPs at the same concentrations caused a 58%, 78%, and 91% mortality rate, respectively. Analysis of gene expression showed dose-dependent downregulation of each parasitism gene Xyl-1, 16D10, and msp-20 genes, neuropeptidergic gene (Ace-2), and expansion-like proteins MAP-1 after treatment with either AgNPs or ZnONPs. On the other hand, the oxidative stress response gene GSTS-1 showed upregulation with all concentrations of AgNPs and ZnONPs. The study concluded that the AgNPs and ZnONPs have efficient nematocidal activity and can be used in Meloidogyne incognita control.

Impact of silver nanoparticles on the micropropagation of Hybanthus enneaspermus and assessment of genetic fidelity using RAPD and SCoT markers

Impact of silver nanoparticles on the micropropagation of Hybanthus enneaspermus and assessment of genetic fidelity using RAPD and SCoT markers

Impact of silver nanoparticles on multiplication, rooting of shoots and biochemical analyses of date palm Hayani cv. by invitro

Nano silver has positive effects on the growth and development of in vitro plants. The current study was carried out to investigate the effect of adding different concentrations of nano silver nitrate (0.0, 1.0, 2.0, 3.0 and 4.0 ml/l) to the culture medium in multiplication and rooting stage of the date palm cv. Hayani. The results showed that there was a significant difference of Ag NPs concentrations in regeneration stage as it increased the number and length of shoots at 3.0 ml/l concentrations compared to the control treatment. The outcome of shoots multiplication experiment indicated that Ag NPs concentration had a significant positive effect on studied traits, when the 3.0 ml/l of Ag NPs added to MS basal medium supplemented with BA at 2.0, GA3 at 0.5 and NAA at 0.1 (mg/l) gave the highest shoots and leaves number as it reached 10.74 shoots and 30.11 leaf/culture with length 6.60 cm, respectively in comparison with lowest results recorded 2.50 shoot/culture, 10.70 leaf/culture with length 2.00 cm, respectively with the control treatment. All shoots were cultivated in a new medium supplemented with NAA at 1.0 mg/l and various concentrations of Ag NPs to study root formation. The findings indicated that the optimal medium for root formation was one that included Ag NPs at 3.0 ml/l which resulted in the highest rooting percentage (85.4%), root number (8.4 root/culture) with length 6.3 cm. In concentration 3.0 ml/l of Ag NPs recorded that, chlorophyll A, chlorophyll B and carotenoids increases to 1.50, 1.10 and 2.33 (mg/g). Also, occurred increase in carbohydrate content to 26.33 mg/g, the proline was enhanced and increased gradually to 3.31 mg/g and protein content to 0.77 mg/g.

Impact of Silver Nanoparticles on Lemon Growth Performance: Insecticidal and Antifungal Activities of Essential Oils From Peels and Leaves.

Ten-year-old lemon (Citrus limon L. cv. Eureka) was used during the 2019 and 2020 seasons to investigate the effect of AgNPs at control, 5, 7.5, and 10 mg/L as a foliar application on vegetative growth, yield, and fruit quality. The selected trees were subjected to agricultural practices applied in the field during the study. The results indicated that the foliar application of AgNPs positively improved the shoot length, total chlorophyll, flower, and fruit set percentage, fruit yield, physical and chemical characteristics of fruits, and leaf mineral composition from macro and micronutrients compared to control in both seasons. The foliar application of AgNPs at 10 mg/L showed the highest mean values followed by 7.5 and 5 mg/L, respectively, for the previous characteristics. The treated leaves and fruit peels were hydrodistillated to extract the essential oils (EOs), and GC–MS analysis of leaf EOs. The analysis of leaves EOs showed the presence of neral, geranial, neryl acetate, and limonene as the main abundant bioactive compounds. While in peel the main compounds were neral, geranial, neryl acetate, D-limonene, geraniol acetate, linalool, and citronellal. Toxin effect of both EOs from leaves and peels were evaluated on the rice weevils (Sitophilus oryzae) and the results indicated a higher effect of lemon peel EOs than leaves based on mortality percentage and the values of LC50 and LC95 mg/L. Melia azedarach wood samples loaded with the produced lemon EOs were evaluated for their antifungal activity against the molecularly identified fungus, Fusarium solani (acc # OL410542). The reduction in mycelial growth was increased gradually with the applied treatments. The most potent activity was found in lemon leaf EOs, while peel EOs showed the lowest reduction values. The mycelial growth reduction percentages reached 72.96 and 52.59%, by 0.1% leaf and peel EOs, respectively, compared with control.

Impact of Silver Nanoparticles in Wastewater on Heavy Metal Transport in Soil and Uptake by Radish Plants

Impact of Silver Nanoparticles in Wastewater on Heavy Metal Transport in Soil and Uptake by Radish Plants

A Review on the Impact of Silver Nanoparticles on Soil Microorganisms and Bioremediation as Heavy Metal Removal Technology

The increasing and varied use of silver nanoparticles (AgNPs) as antimicrobial on consumer products increases the risk of the nanomaterial release into the environment and potentially harm beneficial microorganisms in soil. Any change in soil microbial composition will lead to soil quality degradation that eventually reduce crop productivity. The negative effect of AgNPs on soil microorganism has been reported by researchers. There are technologies employed to remove heavy metals from soil such as chemical, physical, and biological technique. However, chemical and physical techniques have some disadvantages e.g high cost and partial removal. Therefore, biological technique including the use of microorganisms (bioremediation) become more favourable. The technique is considered as cost effectiveness and environmentally sustainable method. The present paper summarizes the impact of AgNPs on soil microorganisms and the use of microorganisms (bacteria, fungi, algae, and yeast) to eliminate heavy metals pollution in soil.

Impact of silver nanoparticles as antibacterial agent derived from leaf and callus of Celastrus paniculatus Willd

BackgroundCelastrus paniculatus Willd. is a rich source of numerous active constituents such as celapanigin, celapagin, malkangunin, celapanin, zeylasteral, pristimerin, and zeylasterone which render medicinal properties to its various parts. Therefore, the present work provides a protocol for the synthesis of AgNPs from in vivo leaf and in vitro developed callus extract of C. paniculatus and both the extracts have great antibacterial potential, which may give immense support for the drug preparation using AgNPs prepared from this valuable medicinal plant.ResultsHigh frequencies of calli induced from leaves and its counterpart, i.e., the natural part leaf were selected as the experimental materials for the green synthesis. The collected data exhibited gradual color variations started with whitish color, creamish, and after 8 weeks it ultimately turns into a solid mass of brownish callus. The silver nanoparticles (AgNPs) were synthesized using in vivo fresh leaves and in vitro developed callus extracts with an indication of brown colored complex. Further confirmation of AgNPs synthesis in both the samples was done using UV-visible spectral analysis followed by X-ray diffraction (XRD) analysis, Fourier transformation infrared spectroscopy (FTIR), and scanning electron microscopic (SEM) analysis.ConclusionThe antibacterial activity of both extracts reflected the presence of the zone of inhibition in both gram-positive and gram-negative bacteria. AgNPs derived from callus extract showed better results with 24.00 ± 1.00 mm zones of inhibition. This protocol deserves the recognition of the antibacterial potential of AgNPs synthesized from CP plant extracts.

Influence of Ag nano particles on spectroscopic and luminescence properties of Dy3+ doped borate glasses

Dy3+ doped lithium zinc borate glasses with silver (Ag) nanoparticles (NPs) were synthesized by the conventional melt quenching method. Impact of silver NPs on the luminescence properties of 59B2O3: 20ZnO: 10Na2O: 10Li2O: 0.5SnO: 0.5Dy2O3 glasses doped with Dy3+ions were investigated. Ag+ ions have been reduced and nucleated to AgNPs by thermochemical redox method. Amorphous characteristics of the glasses were confirmed by XRD measurements. Raman and Fourier transform infrared spectra were used to estimate structural and vibrational bands of the glass samples. Localized surface plasmon resonance (LSPR) band is observed at 419 nm for 0.3 mol% of Ag along with three absorption bands of dysprosium were observed. Luminescence studies were performed on these glasses and found that three emission bands at 484, 575, and 665 nm when excited with wavelength of 349 nm, which corresponds to 4F9/2 to 6H15/2, 4F9/2 to 6H13/2, and 4F9/2 to 6H11/2 transitions of Dy3+ ions.

Impact of silver nanoparticles and two biological treatments to control soft rot disease in sugar beet (Beta vulgaris L)

BackgroundSoft rot disease caused by Pectobacterium carotovorum was observed in various crops which lead to yield shortages and economic losses.Main bodyTherefore, both in vitro and in vivo experiments, aim to assess the effect of nanoparticles and biological treatments to control soft rot disease in sugar beet plant. The treatments comprised three silver nanoparticles (Ag NPs) concentrations (50, 75, and 100 ppm), three Spirulina platensis extract concentrations (50, 75, and 100%), and Bacillus subtilis (1 × 109 CFU ml) 100%. Under in vitro condation, results of the antibacterial activity showed that the zones of inhibition recorded 4.33 cm for 100 ppm Ag NPs, 0.43 cm for 100% algal extract, and 0.2 cm for bacterial treatments. Also, disease incidence % of bacterial soft rot was significantly decreased in all treatments in pot and field experiments. For resistant enzymes activity, B. subtilis 100% showed the most effect (84 mg min−1), followed by S. platensis extract 75%, (57 mg min−1), and Ag NPs 75 ppm (44 mg min−1), for poly phenol oxidase (PPO) at 81 days after sowing (DAS), but at 102 DAS revealed opposite results. On the contrary, peroxidase (PO) at 81 DAS showed different effects where treatment with S. platensis extract 100% increased it significantly (0.546 mg min−1) compared to control (0.535 mg min−1). The same trend was observed at 102 DAS. These results were reflected on sugar quality where Ag NPs 100 ppm treatment recorded the highest significant value (20.5%) followed by S. platensis 75% (19 %); however, the differences among them were not statistically significant.ConclusionThis study indicated that the potential benefits of using silver nanoparticles and two biological treatments to control soft rot disease in sugar beet (Beta vulgaris L).

Effect of Silver Nanoparticles on Aquatic Organisms

Silver nanoparticles are extensively used in the past few years. The presence of these silver nanoparticles concerns the risks they pose to the environment as a whole. Their tiny size and higher surface area make them a very potent threat in the aquatic ecosystem. The interactions and bioaccumulation in the aquatic ecosystem have led to disturbances in the food chain of the aquatic organism. The silver nanoparticles have caused biochemical, physiological, morphological, and neurological impairment in the aquatic organisms. There are several studies that not only report the direct impact of these AgNPs on the water bodies but also report the impact of ligand-bound AgNPs on aquatic invertebrates at different trophic levels and different medium. This literature review attempts to integrate recent findings on the impact of silver nanoparticles and associated studies on aquatic organisms.

Impact of silver nanoparticles on hepatic enzymes and thyroid hormones in striped catfish, Pangasianodon hypophthalmus (Pisces: Pangasiidae)

Nanotechnology is the exploitation of physical, chemical, and biological characteristics of the particles with less than 100 nanometers in size. The most of the produced nanoparticles (56%) are composed of silver. The high consumption of these materials in industry and household products has led to their frequent release in aquatic ecosystems. The median lethal concentration (LC50) and the impact of silver nanoparticles on liver enzymes (ALP, LDH, AST, ALT) and thyroid hormones (T4 and T3) in Pangasius hypophthalamus wereinvestigated in the present study in three steps: At first, OECD (The Organization for Economic Cooperation and Development) protocols were used to determine the fatal levels of the silver nanoparticles (Ag NPs) in striped catfish. Second, semi-lethal concentration was found as 37.32 µg L-1 via regression test. In the last step, 168 fish received 0, 3.37, 7.46, 18.66 µg l-1 Ag NPs with three replicate. Six fish were randomly selected after 14 days from each replicate. Whole fish body extraction was used to measure the liver enzymes and thyroid hormones. The results suggested that due to the lower LC50 of Ag NPs in striped catfish, this species is more susceptible compared to various other fish species. Exposure to the silver nanoparticles with different concentrations significantly increased the levels of liver enzymes (ALP, LDH, AST, ALT) and also significantly decreased the T3, but no effect on T4.

Impact of silver nanoparticles on the growth, fatty acid profile, and antioxidative response of Nannochloropsis oculata

AgNPs caused significant toxicity and induced oxidative stress in the microalga N. oculata. Also, the interaction between AgNPs and algae led to cell membrane damage. Silver nanoparticles (AgNPs) have been broadly applied in several industrial sectors, and thus inevitably released into the aquatic environments. In the present study, the effect of various concentrations of AgNPs (up to 50 mg/L) on the microalga Nannochloropsis oculata (N. oculata) was investigated. The obtained results showed that half maximal effective concentration (EC50) of AgNPs for the microalga was 20.88 mg/L. Also, the different applied concentrations of AgNPs inhibited the cell growth as well as the photosynthetic machinery and stimulated the production of malondialdehyde (MDA) and hydrogen peroxide (H2O2). AgNP treatments dramatically enhanced the content of carotenoids in the treated algae, while they significantly reduced the quantity of phenolic compounds. Furthermore, AgNPs increased the enzymatic activity of catalase (CAT), ascorbate peroxidase (APX) and lactate dehydrogenase (LDH), while they considerably decreased the activity of polyphenol oxidase (PPO) compared to the control sample. Gas chromatography–mass spectrometry (GC–MS) examination demonstrated that after exposure of N. oculata cells to AgNPs, the amounts of saturated fatty acids (SFAs) and polyunsaturated fatty acids (PUFAs) were raised, while the levels of monounsaturated fatty acids (MUFAs) were lessened. The Fourier transform infrared spectroscopy (FTIR) results and the microscopic images revealed the interaction of AgNPs with the cells of N. oculata.

Impact of silver nanoparticles on plant growth, some biochemical aspects, and yield of fenugreek plant (Trigonella foenum-graecum)

BackgroundThe use of nanotechnology can ensure food security via improving crop production. Nanoparticles have the ability to enhance growth and yield of different plants such as fenugreek (Trigonella foenum-graecum) (Fabaceae). The present work aims to study the role of silver nanoparticles (AgNPs) on growth, some biochemical aspects, and the yield both quantitatively and qualitatively of fenugreek plant. AgNPs were synthesized by chemical reduction of silver nitrate with trisodium citrate.ResultsFoliar application of AgNPs with different concentrations (20, 40, and 60 mg/l) improved the growth parameters of fenugreek plant (e.g., shoot length, number of leaves/plant, and shoot dry weight) and increased some biochemical aspects such as photosynthetic pigment (chlorophyll a, chlorophyll b, and carotenoids) and indole acetic acid (IAA) contents thus enhanced the yield quantity (number of pods/plant, number of seeds/pod, weight of seeds/plant, and seed index) and quality (carbohydrate%, protein%, phenolics, flavonoids, and tannins contents) of the yielded seeds as well as increasing antioxidant activity of the yielded seeds.ConclusionThe most effective treatment was 40 mg/l as it caused the highest increases in the studied parameters.

Impact of silver nanoparticles (AgNP) on soil microbial community depending on functionalization, concentration, exposure time, and soil texture

BackgroundIncreasing exposure to engineered inorganic nanoparticles takes actually place in both terrestric and aquatic ecosystems worldwide. Although we already know harmful effects of AgNP on the soil bacterial community, information about the impact of the factors functionalization, concentration, exposure time, and soil texture on the AgNP effect expression are still rare. Hence, in this study, three soils of different grain size were exposed for up to 90 days to bare and functionalized AgNP in concentrations ranging from 0.01 to 1.00 mg/kg soil dry weight. Effects on soil microbial community were quantified by various biological parameters, including 16S rRNA gene, photometric, and fluorescence analyses.ResultsMultivariate data analysis revealed significant effects of AgNP exposure for all factors and factor combinations investigated. Analysis of individual factors (silver species, concentration, exposure time, soil texture) in the unifactorial ANOVA explained the largest part of the variance compared to the error variance. In depth analysis of factor combinations revealed even better explanation of variance. For the biological parameters assessed in this study, the matching of soil texture and silver species, and the matching of soil texture and exposure time were the two most relevant factor combinations. The factor AgNP concentration contributed to a lower extent to the effect expression compared to silver species, exposure time and physico–chemical composition of soil.ConclusionsThe factors functionalization, concentration, exposure time, and soil texture significantly impacted the effect expression of AgNP on the soil microbial community. Especially long-term exposure scenarios are strongly needed for the reliable environmental impact assessment of AgNP exposure in various soil types.

Impact of silver nanoparticles on wastewater treatment in the SBR

The commonly application of nanoparticles (NPs) in commercial and industrial products inevitably increases their release into the natural environment which poses a threat to human health and ecosystems. A recent study of nanoparticles in wastewater treatment showed that most NPs are retained in the equipment used for biological wastewater treatment. The aim of the study was to determine the effects of silver nanoparticles (Ag NPs) on wastewater treatment in the SBR bioreactor. The effluent from the SBRs was analyzed for total organic carbon (TOC), suspended solids (SS), pH and total silver. Microbial observations of activated sludge were made and, on this basis, the Madonia biotic index was specified. After nanoparticles were added, the composition of microorganism communities of the activated sludge changed, and the largest community was the one of creeping ciliates. The efficiency of the effluent treatment measured by the concentration of TOC removal showed that Ag NPs were found to have remarkable effects on TOC removal in the SBR. The obtained results showed that purified wastewater included a low concentration of Ag nanoparticles. The main removal pathway of Ag NPs was via sorption as well as possible aggregation and sedimentation onto the sludge.

Silver and zinc oxide nanoparticles induce developmental and physiological changes in the larval and pupal stages of Spodoptera littoralis (Lepidoptera: Noctuidae)

Abstract The rapid growth of nanotechnology application in various fields of science led to need of understanding their possible effects on development and physiology of insects before using them as control agents. Instead of feeding on a toxic dose, the impact of silver nanoparticles (AgNPs, 50–60 nm) and zinc oxide nanoparticles (ZnONPs, 10–30 nm) was studied at a nonlethal concentration on the larval stages of Spodoptera littoralis. Late second instar larvae of S. littoralis were treated with water, 10 mg/mL AgNPs and ZnONPs dipped castor leaves for 6 days. Both nanoparticles treated leaves caused reduction in both larval weight gain and pupal weight than water dipped leaves while ZnONPs only caused extended larval period. ZnONPs increased total hemocyte, granular cell and plasmatocyte counts while AgNPs increased plasmatocytes only. ZnONPs decreased the levels of protein, lipids and carbohydrates than control and AgNPs treated larvae. On the contrary, ZnONPs induced significant increase in the activities of amylase, glucose 6 phosphate dehydrogenase (G6PD), lipase as well as two antioxidative enzymes, the catalase and superoxide dismutase. These results clearly show that ZnONPs ingestion interfere with the digestive and immunological physiology as well as the development of S. littoralis.