جستجوی مقالات مرتبط با کلیدواژه « نانو ذرات نقره » در نشریات گروه « زیست شناسی »

This research was designed in order to increase the quality and longevity of Alstroemeria cut flowers after harvesting. In this study, the puls treatment of salicylic acid at three levels of 50, 100 and 150 mg/liter and then the preservative solution of silver nanoparticles 2 mg/liter with 3% sucrose was used. Distilled water and silver nanoparticles with sucrose were used as controls. The experiment was conducted as a factorial in the form of a completely randomized statistical design with 5 treatments and 3 replications (each treatment included 5 Alstroemeria cut flower branches). Sampling and measurement of desired traits were done on the 5th, 10th and 15th days of the experiment. The results showed that the highest relative fresh weight, solution absorption rate, percentage of cell membrane stability index and shelf life of Alstroemeria cut flowers were in salicylic acid 150+ silver nano particles+ sucrose Treatment. The highest amount of soluble solids, anthocyanin content and total chlorophyll was obtained in salicylic acid 100+ silver nanoparticles+ sucrose treatment. Therefore, concentrations of 100 and 150 mg/L of salicylic acid with nanoparticles 2 mg/L and sucrose 3% can be recommended to improve the morphophysiological characteristics and shelf life of Alstromeria spp.

One of the environmentally friendly synthesis methods is the synthesis of nanoparticles using plants. Silver nanoparticles are metal nanoparticles with anticancer activity. This study aims  to investigate the effect of silver nanoparticles synthesized from Digitalis nervosa hydroalcoholic extract on MCF-7 breast cancer cell line.

In this experimental study, silver nanoparticles were synthesized from the hydro alcoholic extract of the Digitalis nervosa.MCF-7 cells were then treated with different concentrations of silver(3.125, 6.25, 12.5,25,50 and 100 μg /ml).The toxicity effects of silver nanoparticles were analyzed by MTT method and after determining the concentration of 50% lethality of silver nanoparticles, the expression changes of P53,Bax, Bcl2 and CDH1 genes were investigated by Real - time PCR method. The obtained data were analyzed using SPSS software and one-way variance statistical test and Tukey's test.

The results of MTT showed that the effect of silver nanoparticles on the viability of MCF-7 cell line is dose-dependent and the highest cytotoxicity is related to the concentration of 100 and the lowest is related to 6.25 μg /ml in a significant way. (P<0.001) Also, the effect of silver nanoparticles with a concentration of 50% lethality (19.55 micrograms/ml) on the expression of P53, Bax, Bcl2 and CDH1 genes showed significant changes compared to the control gene.

Silver nanoparticles synthesized by green method from Digitalis nervosa  induce apoptosis in MCF-7 cell line and the use of these nanoparticles can be considered as a promising choice in the treatment of breast cancer.

The filtration rate is one of the physiological indices in bivalves that indicates the degree of the effectiveness of the filtration function in exposure to contaminants. In this study, the changes in filtration rate of Dressina poly morpha were investigated after 7 and 14 days of exposure to silver nanoparticles. Bivalves were removed from the natural environment and transferred to the laboratory. The distribution of nanoparticles in water tanks was tested with the DLS device. Bivalves were exposed to concentrations of 0.25, 2.5 and 25 ppm of nanoparticles for 14 days. The results showed the highest filtration rate for the control group (96 ± 47.74 ml min-1 g-1DW). On day 7, the highest filtration rate was observed in the first treatment (88.58 ± 64.38 ml min-1 g-1DW) and the lowest filtration rate was observed in treatment 3 (47.67 ± 11.81) ml min-1 g-1DW), no significant difference was observed in the filtration rate betwen first treatment and control (P >0.05), but the filtration rate in the third treatment was significantly (P <0.05) lower than that of the other treatments and the control group. Moreover, the filtration rate on day 14 showed similar differences to day 7, but more significant. Therefore, it can be concluded that filtration rate changes are a good indicator for nanoparticles contamination.

Thymus vulgaris and silver Nanoparticles has been demonstrated. Each of these agents for maximum impact requires a high concentration of substances affecting microorganisms. Assuming an anti-microbial agent with low concentration and in combination with other anti-microbial agents as the initial impact or more, A study to evaluate the effect of ethanol extract of propolis interference, Thymus vulgaris essential oil and silver nanoparticles on gram-positive bacteria (Staphylococcus aureus, Streptococcus pneumoniae, Listeria monocytogenes) and Gram-negative bacteria (Proteus mirabilis, Klebsiella pneumonia and Pseudomonas aeruginosa) and on Candida albicans was performed. Microbial used in this study are taken from Iranian Research Organization for Science and Technology. Propolis is collected from different area of west Azerbaijan beehives. The ethanolic extract of propolis have prepared after 3 days. The interfering effects of these agents are evaluated by Micro-broth dilution method on Muller Hinton Broth in the presence of gentamicin as positive control for bacteria and Nistatin against Candida albicans. Acquired Minimum Inhibitory Concentration (MIC) show the effective interfering of these agents. The results of the Minimum Inhibitory Concentration (MIC) of propolis extract with silver nano particle on Klebsiella pneumonia was 25 µgr/ml, on Streptococcus pneumonia, Pseudomonas aeruginosa and Candida albicans was 50µgr/ml and on Staphylococcus aureus, Listeria monocytogenes and Proteus mirabilis was 100 micrograms per milliliter. MIC of Thymus essential oil with silver nanoparticles on Klebsiella pneumonia and Pseudomonas aeruginosa was 50µgr/ml, on Staphylococcus aureus, Streptococcus pneumonia and Candida albicans was 100 µgr/ml and on Listeria monocytogenes and proteus mirabilis was 200 micrograms per milliliter.

Lemon balm (Melissa officinalis) is a medicinal plant belonging to lamiaceae and is rich in antioxidant compounds. with the aim of optimizing the production of antioxidant compounds, in this research, we studied the effect of different concentrations of silver nanoparticles on growth indices and antioxidant activity of proliferated shoots in vitro culture. For this purpose, seedlings of seed germination in MS medium were transferred for propagation to MS culture medium containing 1 mg / l BAP and 0.5 mg / l NAA. after one month, silver nanoparticles with concentrations of 0, 1, 2, 3 and 4 ppm were added to the culture medium  and growth indices, antioxidant activity by free radical scavenging (DPPH), reducing power (RP) and superoxide anion scavenging activity (SOD) and phenolic and flavonoid compounds compositions of the proliferated shoots at 14 and 28 days intervals were measured after treatment. The results of growth analysis showed that increasing the concentration of silver nanoparticles from 1 to 4 ppm increased growth indices (fresh and dry weight of the plant, shoot and root length, number of leaves and number of shoots). This increase was evident 28 days after treatment. The number of leaves and the number of brancheswere affected more than other indices. The lowest amount of IC50, the highest activity reducing power activity (RP) and superoxide anion scavenging activity (SOD), and the highest amount of phenoli and flavonoid compounds were observed in the treated shoots with a concentration of 1 μg / ml silver nanoparticles for 28 days. Generally higher concentrations of silver nanoparticles for growth indices and its lower concentration is suggested to be useful for the production of antioxidant compounds.

Considering the high resistance to drug in methicillin-resistant Staphylococcus aureus, this study was performed to investigate the effects of silver and copper nanoparticles and their combined effect on the methicillin-resistant Staphylococcus aureus in vitro and animal models.

To determine the most effective antibiotics, disk diffusion method was performed. The microdilution method is used for determination of Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of copper and silver nanoparticles and their combination . Then, to examine the effect of nanoparticles and the antibiotic, experiments were performed in the animal models. For this purpose, after intraperitoneal inoculation of bacterial suspension, MBC concertrations obtained from microdilution method were injected to the mice and after the cultivation of spleen, colony count was performed.

The most effective antibiotic on bacteria was vancomycin. The MIC of silver and copper nanoparticles, vancomycin, silver and copper nanoparticles, silver nanoparticles-vancomycin and copper nanoparticles- vancomycin were 1250 ppm, 2500 ppm, 78/12, 625 ppm, 35 ppm and 250 ppm respectively. In animal model, the lowest number of colonies is related to silver nanoparticles and then silver nanoparticles-vancomycin.

The results show that antimicrobial effect of silver nanoparticles is more than vancomycin and copper nanoparticles. Also the combination of silver and copper nanoparticles increases their antimicrobial strength and the combination of silver and vancomycin after complementary experiments, can be a option for the treatment of infections caused by these bacteria.

Nowadays, metal nanoparticles, especially silver, due to their special physical properties and anti-cancer effects have been considered.One of the methods of synthesis of these nanoparticles is the use of plant extracts. The aim of this study was to investigate the anti-cancer effects of silver nanoparticles synthesized of the hydroalcoholic extract of Digitalis nervosa on the cancer cell line (Hela). In this experimental study,the synthesis of silver nanoparticles was performed by adding the hydroalcoholic extract of Digitalis nervosa to the silver nitrate solution. Physical and chemical properties of synthesized nanoparticles were determined by UV-vis, TEM, SEM, EDX and XRD methods.Viability of Hela cancer cells by MTT method with different concentrations of synthesized silver nanoparticles(3.125 to 100 mg/ml) and the expression of Bax, Bcl2, P53 and CDH1 genes were evaluated using real time PCR technique in 24 hours.Data were analyzed using GraphPad software and one-way ANOVA test.P<0.05 was considered statistically significant. The results showed that the results of cytotoxicity at different concentrations of silver nanoparticles showed that IC50 was16.66 μg /‌ml, respectively. Also, the expression of Bax, CDH1 and P53 apoptotic genes in concentration-(16.66μg/‌ml) increased and Bcl2 gene expression decreased compared to the reference gene, which showed the effects of cytotoxicity and changes in nanoparticle concentration. Silver nanoparticles synthesized from the extract of the Digitalis nervosa plant have a cytotoxic effect and possibly induce apoptosis on Hela cancer cells.

Silver nanoparticles (AgNPs) have been considered by researchers as a very strong inhibitor due to their biological properties and have many applications in prevention and treatment. However, there is little information about the effect of nanoparticles on healthy cells.The aim of this study was to investigate the effect of silver nanoparticles on the viability percentage of normal skin cell line MHFB-1.

In this study, during 24, 48 and 72 hours, different concentrations of silver nanoparticles (1.56, 3.125, 6.25, 12.5, 25, 50 and 100 μg / ml on MHFB-1 cell line was evaluated by MTT method.Data obtained from the test were statistically analysed using SPSS software, one-way ANOVA, Tukey test and significance level of P <0.05.

Treatment of normal MHFB-1 cells with different concentrations of silver nanoparticles after 24, 48 and 72 hours by  MTT method showed a significant reduction  in the viability of cells at  concentrations of 25, 50 and 100 μg /ml.

The results of this study showed a dose-dependent inhibitory effect of silver nanoparticles on normal skin cell line (MHFB-1).

Iris pseudacorus is a perennial herbaceous belonging to the Iridaceae family. This family consist of about 300 species of flowering plants with lush flowers. This genus spread widely from the temperate to the coastal areas in the Northern Hemisphere. This study was conducted to investigate the effects of silver nanoparticles on morphological and physiological properties of Iris pseudacorus under in vitro conditions based on a completely randomized design with 5 replications. In this experiment, different concentrations of silver nanoparticles (0 as a Control, 5, 10, 20, 40, 80 and 160 mg/l) were used as an experimental treatment. The variance analysis showed that the effect of silver nanoparticles on leaf number, seedling length, mean leaf length, regeneration percentage, leaf area, seedling number, chlorophyll a, chlorophyll b, carotenoid, flavonoid and phenol were significant at 1% probability level. The comparison of data means on morphological traits also showed that the highest leaf number, seedling length, leaf mean length, regeneration percentage, leaf area and the number of seedlings were obtained from silver nanoparticles at the rate of 5 mg/L. The results of the data mean comparison on the total phenol and flavonoid of marsh iris showed that the highest amount of total phenol was observed in 10 mg/L of silver nanoparticles and the highest amount of total flavonoid was in silver nanoparticles at the rate of 40 mg/L. On the other hand, the highest amount of chlorophyll a, chlorophyll b, and carotenoids was obtained at 5 mg / l of silver nanoparticles.
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The effects of water-borne silver ions and nanoparticles on oxidative stress responses, plasma liver enzymes and some other biochemical characteristics of blood parrot fish were investigated. For this study, 60 parrot fishes (average weight 25.5±6.5g) were randomly distributed into three different treatments including control, silver nanoparticles (250 μg/L) and silver ions (250 μg/L) for 5 days, without feeding during stress. The results showed that the effect of silver ions on plasma oxidative indices and liver enzyme levels was significantly higher than silver nanoparticles, meanwhile, they were significantly higher than control (P<0.05). Silver ion and nanoparticles also induced significant elevation on plasma protein, albumin and globulin levels in comparison to the control, but the effects of both chemicals on the recently mentioned characteristics were the same (P>0.05). In general, the results showed that both nano silver and ion could affect some physiological aspects of the blood parrot, but silver ions showed the highest effects.

Silver nanoparticles (AgNPs) with very strong antimicrobial and anti-proliferative properties are widely used in medical sciences. However, little is known about their effect on healthy cells, and there were the reports of their toxicity. This study aimed to investigate the effect of silver nanoparticles on the viability rate of the MRC-5 cell line. In this experimental study, during 24, 48, and 72 hours, different concentrations of silver nanoparticles (1.56, 3.125, 6.5, 12.5, 25, 50, and 100 μg/ml) per category MRC-5 cells were examined by MTT assay. Data were analysed using SPSS software, one-way ANOVA, Tukey test, and a significant level of p < /em> < 0.05. The treatment of normal MRC-5 cells with different concentrations of silver nanoparticles after 24, 48, and 72 hours by MTT method showed a significant reduction in the viability of cells at concentrations of 25, 50, and 100 μg/ml (p < /em> < 0.05). The results of this study showed that silver nanoparticles have a dose-dependent inhibitory effect on normal MRC-5 cells.

In this research, biological synthesis of silver nanoparticles from Aspergillus fumigatus fungus and cytotoxicity and its antioxidant properties was investigated. Aspergillus fumigatus mushroom was cultured in Sabouraud Dextrose Broth. For the production of silver nanoparticles, supernatant from the culture was exposed to a solution of silver nitrate with a final concentration of 1 mM. Approval of silver nanoparticles production was confirmed by spectrophotometry, X-ray diffraction and Transmission Electron Microscopy. Investigation of the toxicity of the solutions was investigated by MTT method. Images obtained from X-ray diffraction show that nanoparticles are spherical and the nanoparticle size is between 5- 40 nm. In this study, the IC50 antioxidant was 0.06 and IC50 was 70.68 cytotoxicity. The IC50 hole has the same cellular and antioxidant properties, so it can be concluded that the nanoparticles produced in this study have good antioxidants.

Silver nanoparticles (Ag-np) have high penetration and antimicrobial effect due to their high    surface-to-volume ratio. The aim of this study was to biosynthesize silver nanoparticles with red algae extract, Gracilaria gracilis, and to investigate their antibacterial activity against a number of standard and drug-resistant pathogenic bacteria.  First, Ag-np were synthesized. To confirm the structure and size of Ag-np, was used X-Ray diffraction spectroscopy, FE-SEM electron microscopy, and X-ray energy dispersive spectroscopy (EDS). The antimicrobial effects of algae extract on bacteria were determined by sequential dilution method. The size of nanoparticles under electron microscopy was between 12 and 46 nm. The nanoparticles were able to inhibit most of standard and antibiotic resistant bacteria, Ag-np at a concentration of 29 μg /ml, on the standard bacteria: S. typhimorium, E. coli, K. pneumonia and the clinically resistant bacteria, E. coli and           K. pneumonia, they had the most inhibitory effect. In contrast, standard and clinically resistant isolates of S. aureus and    standard strain S. pneumonia were resistant to Ag-np. The results of this research showed that the G. gracilis red algae as a bio-source that can be useful for green synthesis of silver nanoparticles at very low cost applications, these nanoparticles can be used as candidates for drug composition.

The aim of this study was improving antioxidant defense system and monitoring some plasma biochemical parameters of parrot fish fed on diet enriched with astaxanthin alone or in combination with bile salt after exposure to water-born silver nanoparticles (AgNPs). 200 parrot fish were randomly distributed in three different treatments as control, astaxanthin and astaxanthin-bile salt. The fish were fed for 90 days and then subjected to AgNPs 250 μg/L for five days and some plasma biochemical parameters were measured before and after AgNPs stress. The results showed that feeding fish with diet enriched with astaxanthin could cause significant reduction in the plasma levels of all studied oxidative enzymes in comparison to the other groups (P<0.05). AgNPs caused significant elevation in the levels of plasma oxidative enzymes in the control while such elevations were not visible in fish fed on astaxanthin (P>0.05). At the end of feeding trail, day 90th, plasma levels of hepatic enzymes, asparat transaminase and alanin transaminase were significantly lower in the astaxanthin - bile salt group (P<0.05); after AgNPs stress, the levels of the mentioned enzymes were significantly reduced in groups of control and astaxanthin, while such reductions were not observed in the group fed on astaxanthin-bile salt diet (P>0.05). The results of this study showed that astaxanthin alone or in combination with bile salt could improve some plasma oxidative and biochemical parameters of parrot fish when the fish were subjected to AgNPs. The positive effect of bile salt on astaxanthin function was observed on some parameters.

TodayToday, synthetic nanoparticles encompass a wide range of particles with unique properties and have many applications in the field of nanotechnology. Due to the emergence and lack of understanding of the consequences of using nanoparticles, investigating the effect of releasing these particles in the environment at various biological levels is important. In this study, the effects of nanoparticles of silver in concentrations of 0, 2.5, 5, 10, 20, 40, 80 and 100 ppm on physiological parameters such as total anthocyanin, total soluble protein and enzyme activities of Catalase, Ascorbate peroxidase and Superoxide dismutase in tomato seedlings (Solanum Lycopersicon) under in vitro were evaluated. The results showed that anthocyanin levels in response to the presence of silver nanoparticles decreased significantly to 10 ppm concentration. The total protein soluble protein increased with increase in the concentration of nanoparticles in the shoot and decreased with increasing concentrations at 20 and 40 ppm compared to the control. The intensity of expression of six protein bands treated with silver nanoparticles also changed. Increasing the concentration of nanoparticles in the medium increased the activities of catalase and superoxide dismutase and decreased ascorbate peroxidase activity in the roots. However, in shoot, increased activity of peroxidase and catalase, and decreased activity of superoxide dismutase in response to high concentrations of silver nanoparticles. The results indicated that the presence of silver nanoparticles in the tomato culture medium leads to responses at physiological and molecular levels.

There are many different methods for the production of silver nanoparticles (Ag-NPs) but, using of plants in the synthesis of nanoparticles due to a cost effective and eco-friendly approach has been extensively noticed. In this study, the biosynthesis of silver nanoparticles by using extract of Origanum majorana and its antimicrobial properties has been reported. In this study, the extract of Origanum majorana as the reducing agent is used for the biosynthesis of silver nanoparticles. Reduction of Ag ion was obtained after 24 h by using extract of Origanum majorana in presence of 1 mM silver nitrate (AgNo3) solution. The size, structural, optical and morphological properties of nanoparticles have been analyzed by facility of: X-ray Diffraction, Field Emission Scanning (Transmission) Electron Microscope. The antimicrobial activities of the silver nanoparticles against Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus was investigated. UV-Vis spectrum exhibit an absorption band at around 400-450 nm suggestion the formation of biological Ag nanoparticles. Size and morphological properties of nanoparticles was performed by TEM which show that particles have spherical shape with diameter of about 30-70 nm. Silver nanoparticles presented the antimicrobial activity against Gram positive and Gram negative bacteria. It seems that green Synthesis of nanoparticles using plant extracts can help to increase their antibacterial. In the present study it was shown that the antibacterial properties of nanoparticles to increase considerably.

Aim and By attention to extensive use of Silver nanoparticles, this study has been done to investigate the effects of silver these particles on ovary tissue and HPG axis.
Adult female rats were divided into five groups. Treatment groups received 25, 50, 100, and 200 mg/kg/day silver nano particles for 30 days orally. Then the rats weighed and levels of FSH, LH, estrogen, and progesterone were measured. Ovaries sections were studied using light microscopy.
The weight of rats and their ovaries, the level of FSH, LH, and Estrogen of serum decreased significantly in 50,100, and 200 mg/kg doses in comparison with the control (pResults have indicated poisonous effects of silver nanoparticles on HPG-axis and ovary tissue that is dose dependent. Therefore, enough precaution must be down in chronic exposure of females.

To assess the acute toxicity of colloidal silver nanoparticles (AgNPs) in Nannochloropsis</em> oculata</em>, microalgal cells were exposed to different concentrations of AgNPs for 72 hours and according to OECD 201. Algal cell count was done every 24 hours and average specific growth rate, as well as percent inhibition of the average specific growth rate, were calculated for each concentration. Also, the amount of inhibitory concentrations (IC) and median inhibitory concentration (IC50</sub>) of this nanomaterial were calculated according to the percent inhibition of the average specific growth rates and by using the Probit Analysis program. The results showed that even at the lowest concentration (0.005 mg/L), silver nanoparticles reduced the growth of Nannochloropsis</em> microalgae. Accordingly, No Observed Effect Concentration (NOEC), Lowest Observed Effect Concentration (LOEC), and IC50 of this nanomaterial for tested microalgae were 0.001, 0.005, and 0.036 ± 0.009 mg/L. On this basis, and considering the Globally Harmonized System of Classification and Labelling of Chemicals (GHS), tested AgNPs are classified as “category acute 1” or “very highly toxic” for N. oculata</em>, so any accidental or intentional release of AgNPs containing wastewaters to aquatic ecosystems may cause irreparable effects on the aquatic environment.