Modares Journal of Biotechnology

Abstract A critical aspect of laboratory techniques in plant in vitro culture involves the disinfection of explants and the maintenance of sterile environments. Ideally, disinfectants should demonstrate efficacy against a broad spectrum of microorganisms at minimal concentrations. However, the rising application of antibiotics has led to the development of microbial resistance to these agents. Currently, compounds such as essential oils and nanoparticles are being explored in microbiological research. This study aimed to evaluate the effectiveness of three antibiotic groups (cefazolin, penicillin, and chloramphenicol) alongside cumin essential oil and silver nanoparticles in managing in vitro contamination in potato plants (Solanum tuberosum L.). The explants underwent 1 min disinfection with 70% ethanol, followed by a 10 min treatment with a commercial bleach solution. Additional disinfection treatments, including cefazolin, chloramphenicol, penicillin, silver nanoparticles, and cumin essential oil, were applied at concentrations of 10, 20, 40, and 80 mg l-1 for nanoparticles, and 100 and 200 mg l-1 for the other agents in the cultivation medium. The findings indicated that cumin essential oil exhibited the highest level of microbial inhibition, while cefazolin showed the least. Notably, the application of nanosilver at 40 mg L-1 resulted in a 73% reduction in bacterial contamination, whereas penicillin at 100 mg L-1 achieved a 67% inhibition rate. Ultimately, essential oils and nanoparticles present viable alternatives to conventional chemical treatments for the elimination and management of in vitro contamination in plant explants under laboratory conditions.

Abstract In the present work, we describe the synthesis of silver nanoparticles (Ag-NPs) using seed aqueous extract of Psidium guajava (PG) and its antibacterial activity. UV–visible spectroscopy, X-ray diffraction (XRD), Fourier transform infra red spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray energy dispersive spectrophotometer (EDAX) were performed to ascertain the formation of Ag-NPs. It was observed that the growths of Ag-NPs are stopped within 35 min of reaction time. The synthesized Ag-NPs were characterized by a peak at 446 nm in the UV–visible spectrum. XRD confirmed the crystalline nature of the nanoparticles of 10-20 nm size. The XRD peaks at 38◦, 44◦, 64◦ and 77◦ can be indexed to the (1 1 1), (2 0 0), (2 2 0) and (3 1 1) Bragg’s reflections of cubic structure of metallic silver, respectively. The FTIR result clearly showed that the extracts containing OH as a functional group act in capping the nanoparticles synthesis. Antibacterial activities of Ag-NPs were tested against the growth of Gram-positive (S. aureus) using SEM. The inhibition was observed in the Ag-NPs against S. aureus. The results suggest that the synthesized Ag-NPs act as an effective antibacterial agent. It is confirmed that Ag-NPs are capable of rendering high antibacterial efficacy and hence has a great potential in the preparation of used drugs against bacterial diseases. The results confirmed that the (PG) is a very good eco friendly and nontoxic source for the synthesis of Ag-NPs as compared to the conventional chemical/physical methods.

Abstract Abstract
Urinary tract infection is one of the most common and common bacterial infections, accounting for a significant proportion of hospital admissions (about 30-40%). Silver nanoparticles work by releasing silver ions against various bacteria. The fact that bacteria are not resistant to nanoparticles is very important and therefore will affect a wide range of bacteria.
Materials and Methods
In this study, 50 specimens of positive cultures with urinary tract infection referred to Imam Reza Hospital Laboratory in Bojnourd were studied. Resistance and susceptibility of the isolates were determined by disk diffusion method. In this study, antibacterial effects of silver nanoparticles were investigated by microdilution method using aqueous extract of Ganoderma leucidum. Vegetative electron microscopy was used to measure the size and shape of silver nanoparticles. In addition, infrared spectroscopy analysis was performed to investigate possible organic compounds involved in the synthesis of nanoparticles.
Results: The highest antibiotic resistance was related to ampicillin (84%). The resulting nanoparticles were 20 to 45 nm in size.
Conclusion:
The produced nanoparticles have antimicrobial activity and can be a good alternative in the treatment of antibiotic resistant infectious diseases.

Abstract Today, nanosilver is one of the most commercialized nanomaterials. The demand for synthesis of Nanosilver through biocompatible routs due to wide biomedical application has increased. Use of plants and plant products as sustainable and renewable resources in the synthesis of nanoparticles is more advantageous over other biological routes. In this study, biosynthesis of silver nanoparticles (AgNPs) using aqueous extract of Withania somnifera as reducing agent is reported. Effect of parameters such as AgNO3 concentration, aqueous extract, pH and formation time were investigated and optimized by UV-visible spectroscopy in the synthesis of nanoparticles. At room temperature, the solution color started to change from pale yellow to dark brown due to the reduction of silver ion. The transmission electron microscopy (TEM) was applied for size and morphological analysis of nanoparticles. TEM result shows a spherical structure with an average size ranging from 24-35 nm for silver nanoparticles.

Abstract
Objectives: In this study, the effect of different concentrations (1-50 mg/L) of colloidal Ag-NPs investigated on the growth, fatty acids profile and biodiesel indices of N. oculata, after estimating EC50 (20.88 mg/L).
Materials and methods: In this research, N. oculata was selected owing to fast growth and its ability to synthesize lipids for biodiesel production. This microalga exposed to colloidal silver nanoparticles under marine conditions for 72 h. The optical density (OD) and fatty acid profiles were investigated using spectrophotometric analysis and gas chromatography, respectively. Statistical analysis growth data was performed using ANOVA and Duncan's multiple test at 2% probability level.
Results: The algal growth significantly decreased in N. oculata cells treated with the 5-50 mg/L of Ag-NPs. The increase of saturated fatty acids (SFAs) and polyunsaturated fatty acids (PUFAs) as well as the decrease of monounsaturated fatty acids (MUFAs) contents were also observed in response to 25 mg/L of Ag-NPs in compared to the control. The important indicators of biodiesel oxidative stability containing LCSF, CFPP and CP increased in N. oculata exposed to Ag-NPs, while the level of DU decreased. The results of this study showed that despite the toxicity of silver nanoparticles, this nanoparticle can increase the biodiesel stability produced from N. oculata.

Abstract Burns are one of the most important accidents related to human health. Receiving proper treatment is very important due to the intense complications associated with them. The improvement and elimination of ulcer effect can be achieved by controlling the wound infection. According to this, wound dressing containing antibiotics is one of the effective methods in wound's infection treatment. The use of silver in burns caring has been considered a long time ago, but silver deposits on the liver that causes some problems which can be overcome with the help of nanotechnology. In this study, Silver-Oak nanoparticles were green synthesized by using the ethanol extraction of Iranian Oak with the help of reducing agent. Nanoparticles formation were followed by UV-Visible spectrum and they characterize with SEM images and XRD spectrum. Then Gelatin-Alginate Hydrogel was prepared as a wound dressing and their properties were investigated by the presence of nanoparticles, oak extraction and without any additives. Nanoparticles' diameter is about 30-65nm which are dispersed in the hydrogel with regular pore size about 30-100μm. Oak extraction increase the hydrogel water uptake that improve the wound hilling. Antibacterial properties of wound dressing against Staphylococcus aurous and pseudomonas are investigated by inhibiting zone.

Abstract Aims: The bio-toxicity of silver nanoparticles (AgNPs) in the aquatic ecosystem and the detection of lethal concentrations of this material are of importance. The aim of this study was in vivo comparative toxicity of silver nanoparticles and bio-productivity in zebrafish (Danio rerio) in embryo and adult stages.
Materials and Methods: The present experimental study was carried out on 30 fertilized eggs and 30 adult zebrafish and the effects of chemical and bio-productivity of AgNPs were evaluated by brown seaweed (Sargassum boveanum) in evolutionary stages of the embryo and adult zebrafish with a control group and in incremental concentrations. The mortality rate was recorded at 24, 48, 72, and 96 hours after exposure and the data were analyzed by EPA Probit Analysis 1.5 and SPSS 19 softwares, using one-way analysis of variance and Duncan's multiple range test.
Findings: The toxicity of both types of AgNPs in both evolutionary stages was increased with increasing concentrations and time (p<0.05). After 96 hours, the lethal concentration 50 (LC₅₀) in adult fish was 0.788mg/l for chemical AgNPs and 0.409mg/l for bio-produced AgNPs. Mortality rate at the highest concentration (3mg/l) of AgNPs at 72 and 96 hours in all groups was 100%.
Conclusion: Comparison of the toxicity result showed that the biosynthesis form of AgNPs is more toxic potential than chemical form of AgNPs. It seems the sensitivity of embryo stage to both of silver nanoparticles more than to mature stage.

Abstract Nanotechnology is a principally attractive area of research related with production of nanoparticles of variable sizes, shapes, chemical compositions and their possible application for human being benefits. Creation, manipulation and utilization of metallic nanoparticles, because of reduction of materials dimensions, affect the physical properties and results in displaying extraordinary thermal, optical and electronic properties of nonmaterial. The biological approaches to synthesis of nanoparticles are better than chemical and physical procedures because of low energy and time expenditure.
In this study the possibility of production of nano-silver particles from dried flower buds of Clove was investigated and antibacterial and anti-fungal activities of produced nanoparticles were studied by diffusion disc and well methods. The displayed UV-visible spectra, with a wavelength of 300 to 600 nm, identifies formation of silver nanoparticles, whenever the colorless initial acclimated mixture turned to brown. The centrifuged powder samples were examined using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) methods. Based on the results of this study, produced silver nanoparticles were spherical in the range of 27 to 69 nm and showed effective antimicrobial activity against Bacillus subtilis, Escherichia coli, Staphylococcus aureus and Saccharomyces cerevisiae. Therefore clove can be used as a biological source for the synthesis of nanoparticles in an industrial scale with a very low cost.

Abstract Microorganisms and plants have high potential for reducing the metal (biosynthesis of nanoparticles) through their metabolic pathways. Apart from the environmental benefits of biosynthesis of nanoparticles, there is the opportunity for production of nanomaterial with new properties in this method. In this study, the fruit aqueous extract of Capparis spinosa L. was used for synthesis of nanoparticles. To evaluate the reducing potential of plant, total phenolic content and antioxidant activities of both aqueous and ethanolic extracts were measured by DPPH and FRAP methods. The aqueous extract showed a lower antioxidant activity than the ethanolic extract; however, it had high potential to reduce the free radicals and metal ions. After preparing the extract, for phytosynthesis of silver nanoparticles, 2 ml of extract was added to 4 ml of 1 mM silver nitrate. The extract was used as a reducing and stabilizing agents of the nanoparticles. The effect of determining parameters for optimizing synthesis of nanoparticles such as: pH of reaction, the amount of extract, concentration of metal ion and time of reaction were evaluated using Ultraviolent-Visible (UV-Vis) spectroscopy and Transmission Electron Microscopy (TEM) .The spectrum of Surface Plasmon Resonance (SPR) of silver nanoparticles showed the maximum absorbance at 415 nm. Fourier Transform Infrared (FT-IR) spectroscopy was used to identify the possible functional groups involved in the synthesis of silver nanoparticles. The Results showed that the nanoparticles were spherical shape and the size of them were about 8-12 nm.

Abstract Nanotechnology involves technological research and development in spaces at the range of 1 to 100 nanometers, and in this technology, very small and atomic scale particles are created and handled. Plant extracts can be used as a green method for the synthesis of silver nanoparticles. In this study, the biosynthesis of silver nanoparticles was performed using extracts of sesame (Sesamum indicum) seeds. Silver nitrate was added to the seed extract, and then it was incubated at 30 ° C. The effects of three concentrations (1mM, 2mM and 3mM) of silver nitrate on the synthesis of silver nanoparticles were studied. The analyses of absorption spectroscopy UV-Visible, Transmission Electron Microscopy (TEM), X-ray Diffraction (XRD) and Inductively Coupled Plasma (ICP) were conducted to assess the production of nanoparticles. UV-Visible spectroscopy analysis and the peak at 420 nm indicated the occurrence of nanoparticles in the extract. TEM image determined that the nanoparticles were spherical with average size of about 14 nm. XRD analysis showed the nano-crystals synthesized by the extract, and Inductively coupled Plasma (ICP) determined the conversion percentage of silver ion into silver nanoparticle as approximately 99.61 percent.

Abstract In biological methods, microorganisms such as bacteria, fungi, actinomycets and yeasts are used to produce metal nanoparticles. Fungi are extremely good candidates in the synthesis of silver nanoparticles because of their ability to secrete large amounts of enzymes. The aim of this study was the biosynthesis of silver nanoparticles by Penicillium spp. isolated from the soil of plump and zinc mine in Zanjan city (Iran). After culturing, growth of colonies and isolation of Penicillium spp., 15 g of the fungal biomass was mixed into 1 mM silver solution for 72 h incubation. The production of silver nanoparticles was characterized by UV-vis spectroscopy, X-ray diffraction(XRD) and transmission electron microscopy. Among the sixteen kinds of isolated fungi, six species were recognized as Penicillium of which just the fungus Penicilliumbrevicompactum was found to be able to produce silver nanoparticles. The production of silver nanoparticles was preliminarily approved by observing the color change of the reaction solution from colorless to yellowish brown. The synthesis of silver nanoparticles was confirmed by observing the characteristic peak at 406-425 nm. The presence of crystalline silver nanoparticles was confirmed by observing peaks in (111), (200), (220), (311) in the XRD analysis. Transmission electron microscopy images showed that silver nanoparticles were produced in the size range of 50 -100 nm in spherical shape mainly extracellular at the surface of mycelium. The fungus was recognized to be Penicilliumbrevicompactumusing slide culture method, growth on Czapek yeast agar and Keratin-sucrose agar.