توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱Antibacterial and anti–adherent activity of great mullein (Verbascum thapsus L.) ethanolic extract on in vitro biofilm formation of three oral streptococci
اطلاعات انتشار: International Journal of Health Studies، اول،شماره۲، ۲۰۱۵، سال
تعداد صفحات: ۳
Introduction: The oral microbial flora comprises one of the most diverse human–associated biofilms. Its development is heavily influenced by oral streptococci. Numerous studies have shown that these bacteria are capable of adhering and forming biofilm on oral cavity and tooth. Verbascum thapsus (VT) is a medicinal plant that chemical constituents of it revealed the presence of biologically active compounds with antibacterial properties. The aim of the present study was to evaluate the antimicrobial and anti–adherent activities of ethanol extract of (VT) against of three oral streptococci in vitro.Methods: In this study, biofilm formation of S. mutans 1683ATCC35.668, S. sanguinis 1449CIP53.15 and S. salivarius 1448 CIP55.128 with ethanol extract of VT was tested using Micro–dilution assay and microtitre plate assay. Results: Results showed that the biofilm formation of three oral streptococci with ethanol extract (leaves and root) of VT was significantly lower than the control group without ethanol extract of VT. Meanwhile, the reduction degree was correlated to the concentration of ethanol extract of VT positively. Discussion: These results suggest that antimicrobial activity of ethanol extract of VT against three oral streptococci. VT extracts have inhibitory effects on biofilm formation of oral streptococci as the reduction of bacterial growth and reduction of biofilm formation ability.

۲Optimizing Primary Recovery and Refolding of Human Interferon–b from Escherichia coli Inclusion Bodies
اطلاعات انتشار: Iranian Journal of Biotechnology، دوازدهم،شماره۴(پياپي ۴۸)، ۲۰۱۴، سال
تعداد صفحات: ۹
Background: The refolding of proteins from inclusion bodies is affected by several factors, including solubilization of inclusion bodies by denaturants, removal of the denaturant, and assistance of refolding by small molecule additives.Objectives: The purpose of this study was optimization of recombinant human interferon β purification in order to achieve higher efficiency, yield, and a product with a better and more suitable biological activity.Materials and Methods: Triton X–100 and sodium deoxycholate were used to wash the recombinant human interferon–β inclusion bodies prior to solubilization. The inclusion bodies solubilization process was performed by denaturants and reducing agents; guanidine–hydrochloride, urea, β–mercaptoethanol and dithiothritol.Results: The best recovery was obtained in the presence of 0.5% TritonX–100 (v\v). Low concentrations of urea only gave a marginal improvement on the refolding of recombinant human interferon–β. Successful refolding was achieved by gradient elution (decreasing the guanidine–hydrochloride concentration) in the presence of L arginine. Partial purification was also achieved continuously, and recombinant human interferon–β was recovered with 93.5% purity. The interferon prepared in this project was biologically active and inhibited the replication of vesicular stomatitis virus in Hela cells, when compared to the standard interferon. Conclusions: In this research, the best recovery of inclusion bodies was found at a concentration 0.5 M of Triton X–100, the maximum efficiency of solubility was found in pH 10.5 and the maximum efficiency of refolding was achieved by final buffer containing 2M urea and 0.6 M L–Arg.

۳A Nested–Splicing by Overlap Extension PCR Improves Specificity of this Standard Method
اطلاعات انتشار: Iranian Journal of Biotechnology، سيزدهم،شماره۲(پياپي ۵۰)، ۲۰۱۵، سال
تعداد صفحات: ۴
Background: Splicing by overlap extension (SOE) PCR is used to create mutation in the coding sequence of an enzyme in order to study the role of specific residues in protein’s structure and function.Objectives: We introduced a nested–SOE–PCR (N –SOE–PCR) in order to increase the specificity and generating mutations in a gene by SOE–PCR. Materials and Methods: Genomic DNA from Bacillus thermocatenulatus was extracted. Nested PCR was used to amplify B. thermocatenulatus lipase gene variants, namely wild type and mutant, using gene specific and mutagenic specific primers, followed by cloning in a suitable vector. Briefly in N–SOE–PCR method, instead of two pairs of primers, three pairs of primers are used to amplify a mutagenic fragment. Moreover, the first and second PCR products are slightly longer than PCR products in a conventional SOE. PCR products obtained from the first round of PCR are used for the second PCR by applying the nested and mutated primers. Following to the purification of the amplified fragments, they will be subject of the further purification and will be used as template to perform the third round of PCR using gene specific primers. In the end, the products will be cloned into a suitable vector for subsequent application. Results: In comparison to the conventional SOE–PCR, the improved method (i.e. N–SOE–PCR) increases the yield and specificity of the products. In addition, the proposed method shows a large reduction in the non–specific products.Conclusions: By applying two more primers in the conventional SOE, the specificity of the method will be improved. This would be in part due to annealing of the primers further inside the amplicon that increases both the efficiency and a better attachment of the primers. Positioning of the primer far from both ends of an amplicon leads to an enhanced binding as well as increased affinity in the third round of amplification in SOE.
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