Showing 4 results for Salehizadeh
Volume 2, Issue 1 (3-2016)
Abstract
Abstract
Background:
Streptococcus mutans in the oral cavities sable to produce mutacin (bacteriocin-like substances) with antibiotic properties. The aim of this study was to investigate the frequency and expression of genes encoding mutacins typeI, II, III and IV and also two of 8 genes in a cluster encoding the putative bacteriocins, the designated bsm 283, bsm 299, bsm 423, bsm 1889c, bsm 1892c, bsm 1896, bsm 1906c and bsm 1914, were also screened by PCR and specific primers for each type of mutacin biosynthesis gene and then mutacin activity against the indicator strains determined.
Methods
: In this study, dental clinic samples were collocated; Streptococcus mutans was detected using biochemical tests and molecular methods (PCR). Frequency of mutacin biosynthesis genes types I, II, III and IV, bsm299 and bsm1899 were measured by PCR, using specific primers for each type of mutacin biosynthesis gene. Furthermore, the antimicrobial spectra of Streptococcus mutans isolates against other indicators, including Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Salmonella typhi, Pseudomonas, Escherichia coli were evaluated using well diffusion, disk diffusion and the minimal inhibitory concentrations (MICs) methods.
Results
: Out of 56 samples collected from patients referred to Milad Hospital dental clinic on October 2011 and three private dental clinics on November 2011, 24 strains of Streptococcus mutans produced mutacins. 67.52% of the strains had a wide antimicrobial spectrum and 37.5% of 67.5% had a high frequency of genes with more inhibitory activity against, Staphylococcus epidermidis, Staphylococcus aureus and Enterococcus faecalis respectively that are more related to putative bacteriocins. The expression frequency of the bsm gene (putative bacteriocins) was higher than that of the characterized mutacins types (I–IV). The lowest dilution rate mutacin was found against Staphylococcus epidermidis (0.0625 unit/mL).
Conclusion
: These findings suggested that all putative bacteriocins may represent a large repertoire of inhibitory substances produced by Streptococcus mutans. Therefore, the high diversity of mutacin-producing phenotypes, associated with high frequency of expression of the biosynthesis genes screened and wide antimicrobial activity against Staphylococcus epidermidis could be used as safe antimicrobial agents in treatment of superficial infections such as, removing the pimple caused by Staphylococcus epidermidis.
Volume 17, Issue 106 (December 2020)
Abstract
Abstract
Ovarian cancer is one of the deadliest cancers in women causing abnormal cancerous cells that can spread and metastasize to other parts of the body. Secondary metabolites are highly variable in terms of structural and chemical properties and they are very important for plants survival. In this study, the extracts of two plants using three different solvents (water, ethanol 80% and methanol 80%) and water bath extraction method were obtained. phenolic compounds of extracts were determined by Folin Sioculto method. DPPH (2, 2-Diphenyl-1-picrylhydrazyl) and FRAP (Ferric reducing ability of plasma) methods were performed for determination of antioxidant properties. The amount of phenolic compounds in two plants was higher in 80% methanol solvent and the most antioxidant activities were observed in water solvent of extracts. Water solvent had the highest antioxidant activity and was selected to investigate the anti-cancer properties of extracts on ovarian cancer cells. Water extract of Ocimum basilicum within72 hours had the highest cytotoxic effect with an IC50 value of 1.105 ± 0.001 mg / ml. In study of antimicrobial activity by disc diffusion method, the highest antibacterial properties were only in ethanol extracts of two plants. In the measurement of MIC and MBC, ethanol and methanol extracts of Ocimum basilicum and water and ethanol extracts in Imatiens walleriana had the most inhibitory and bactericide effects.
Me. Reyahipoor, A.r. Shafiei, S.a.m. Salehizadeh,
Volume 19, Issue 11 (November 2019)
Abstract
The material point method (MPM) is a numerical technique to modeling the large deformation and interaction between different phases of materials. MPM combines the best aspects of both Lagrangian and Eulerian formulations while avoiding some shortcomings of them. In MPM a body is modeled with the particles which carry all physical properties of the continuum such as mass, momentum, strains and stresses. The background mesh is used to solving the momentum equation. In the first phase, information is mapped from particles to nodes. In the second phase, momentum equations are solved for the nodes, and then the updated nodes are mapped to the particles to updating their positions and velocities. In the third phase the grid is reset. In numerical simulation of granular flows, large deformations and interactions between grain boundaries and buildings lead to the complexity in the structural behavior of the material and, as a result, the complexity of the simulations. From different numerical techniques, the material point method is a suitable method for simulating such problems. In this study, the problem of the collapse of a column of granular material on a rigid wall was simulated in two dimensions through material point method. The surface profile and displacement of the front were compared with the laboratory results which a good accordance is observed between them. The results show that the ratio of the initial column plays an important role in the development of granular mass.
Volume 19, Issue 124 (June 2022)
Abstract
The mixture of cellulose acetate (CA), and poly (ethylene oxide) was electrospun into Nanofibrous webs using an acetic acid solution. The impact of cellulose acetate (CA)/ polyethylene oxide (PEO) ratio (1, 1.5, 2 wt %), sodium dodecyl sulfate (SDS) (0, 1.5, 3%, w/w) and ammonium oxalate (3%, w/w) on the diameter, tensile strength, elongation and porosity (PO) of the Electrospun Nano-fibers (ENFs) were enhanced applying response surface methodology-central composite rotatable design (RSM-CCRD). The ENFs were formed of non-woven fibers with a maximum diameter of 163 nm. Second-order polynomial models with high R2 values (0.86–0.97) were developed using Cubic analysis. The outcome revealed that the ENFs morphology and diameter were noticeably affected by CA, PEO, and SDS. The overall optimum condition was identified to be at the compounded level of CA to PEO ratio of 2 wt % and SDS content of 3% (w/v). At the best point, diameter, surface tension, elongation, and porosity of the fabricated electrospun nanofibers (ENFs) were 99 nm, 0.017 N/mm2, 5 mm and 17.54 respectively. The most fabricated ENFs were uniform and bead-free with high active sites and mechanical strength, which could be used in different fields.
