Electrodeposition of homogeneous and adherent polypyrrole/Na<Superscript>+</Superscript>-cloisite nanocomposite on iron electrodes

In this work homogeneous and adherent nanocomposite of polypyrrole (PPY) with Na⁺-Cloisite nanoclays was successfully prepared by insitu electropolymerization of pyrrole monomer in the presence of Na⁺-Cloisite nanoclays. Formation of nanocomposite and incorporation of nanoclays in polypyrrole matrix was endorsed and characterized by FTIR spectroscopy studies, X-ray diffraction (XRD) pattern and scanning electron microscopy (SEM). The X-ray difraction patterns showed that PPY was intercalated between clay layers in the order of nanoscale. The morphology of the resulted nanocomposite was studied by scanning electron micrograph (SEM). Cyclic voltammetry experiments were carried out in different electrolytes and showed that nanocomposite is electroactive, while conductivity of the nanocomposite derived from four point probe technique indicated that the resulted nanocomposite is conductive. The anticorrosive properties of a thin layer coating of PPY/Na⁺-Cloisite nanocomposite on iron coupons was evaluated and compared with pure polypyrrole coating. According to the results in various corrosive environments PPY/Na⁺-Cloisite nanocomposite has enhanced corrosion protection effect in comparison to pure polypyrrole coating. It was observed that the corrosion protection effect was due to the dispersion of nanoclays in polymer matrix, which results in the increase in the corrosion potential and decrease in corrosion current and corrosion rate.     

Manufacturing polymethyl methacrylate nanofibers as a support for enzyme immobilization

Nanofibers have a great potential for enzyme immobilization application due to their large surface area to volume ratio besides their porous structure. In this work, we produce polymethyl methacrylate (PMMA) nanofibers via electrospinning method in dimethylformamide (DMF) as solvent. Thereafter, we employ a chemical method on final PMMA nanofiberous web to covalently immobilize acetylcholinesterase (AChE) enzyme on membrane surface. Morphology and tensile properties of nanofibers are studied as first steps of characterization to make sure of obtaining a properly stable membrane for enzyme carrying application. Thereafter, the stability and activity of immobilized enzymes as two main characteristic parameters are tested and reported for different applications such as biosensor manufacturing.     

An Enterovirus-Like RNA Construct for Colon Cancer Suicide Gene Therapy

Background:

In gene therapy, the use of RNA molecules as therapeutic agents has shown advantages over plasmid DNA, including higher levels of safety. However, transient nature of RNA has been a major obstacle in application of RNA in gene therapy.

Methods:

Here, we used the internal ribosomal entry site of encephalomyocarditis virus and the 3’ non-translated region of Poliovirus to design an enterovirus-like RNA for the expression of a reporter gene (enhanced green fluorescent protein) and a suicide gene (thymidine kinase of herpes simplex virus). The expression of these genes was evaluated by flow cytometry and cytotoxicity assay in human colorectal adenocarcinoma cell line (SW480). We then armed RNA molecules with a target sequence for hsa-miR-143 to regulate their expression by microRNA (miRNA) mimics.

Results:

The results showed effective expression of both genes by Entrovirus-like RNA constructs. The data also showed that the restoration of hsa-miR-143 expression in SW480 leads to a significant translation repression of the introduced reporter and suicide genes.

Conclusion:

Collectively, our data suggest the potential use of Entrovirus-like RNA molecules in suicide gene therapy. Additionally, as a consequence of the possible downregulated miRNA expression in cancerous tissues, a decreased expression of gene therapy constructs armed with target sequences for such miRNA in cancer tissue is expected.Key Words: Thymidine kinase, Polio 3’NCR, miR-143     

Assessment of Iranian wheat germplasm for salinity tolerance using analysis of the membership function value of salinity tolerance (MFVS)

Journal of Crop Science and Biotechnology - Salinity stress is one of the most important abiotic stresses which reduce crop production worldwide. In this study, 17 morphological and agronomic...     

Beet sugar syrup and molasses as low-cost feedstock for the enzymatic production of fructo-oligosaccharides

Sugar syrup and molasses from beet processing containing 620 and 570 mg/mL sucrose, respectively, were assayed as low-cost and available substrates for the enzymatic synthesis of fructo-oligosaccharides (FOSs). A commercial pectinase (Pectinex Ultra SP-L, from Aspergillus aculeatus) characterized by the presence of a transfructosylating activity was used as a biocatalyst. The FOS production increased when lowering the initial pH value of syrup (7.5) and molasses (8.9) to 5.5. Sugar syrup and molasses were diluted in order to reduce substrate viscosity; interestingly, the percentage of FOS with regards to total sugars remained almost constant, which indicated a high transferase-to-hydrolase ratio for this enzyme. Kinetics of FOS production was analyzed. Using approximately 10 U transfructosylating activity per g sucrose, the FOS concentration reached a maximum of 388 mg/mL after 30 h using syrup and 235 mg/mL in 65 h with molasses. These values corresponded to approximately 56 and 49% (w/w), respectively, of the total amount of carbohydrates in the mixture. The enzyme was also covalently immobilized on an epoxy-activated polymethacrylate-based polymer (Sepabeads EC-EP5). We found that immobilized Pectinex Ultra SP-L can be efficiently applied to the synthesis of FOS using syrup and molasses as substrates.     

Effects of environmental factors and burial depth on seed germination and emergence of two populations of Caucalis platycarpos

Caucalis platycarpos is a weed species in irrigated and dry land farming systems in East Azerbaijan and Kermanshah provinces of Iran. Experiments were undertaken to compare C. platycarpos seed germination and emergence of a population from each province over a range of environmental factors, burial depth and crop residue treatments. The Azerbaijan population required lower temperatures (20/10°C day/night temperature) for its highest (90%) germination, compared with the Kermanshah population (88% germination at 25/15°C day/night temperature). In both populations, germination was 84–90% over a wide range of light/dark periods (10–24 h light), but considerable reduction (up to 42%) occurred under continuous darkness. The osmotic potential required for 50% inhibition of germination was ?0.54 and ?0.40 MPa for Azerbaijan and Kermanshah populations respectively. The NaCl concentration of 8.83 and 5.71 dS m^?1 caused 50% inhibition of germination in Azerbaijan and Kermanshah populations respectively. The X₅₀ parameter (the burial depth at which emergence is reduced by 50%) for Azerbaijan and Kermanshah population was 2.18 and 2.86 cm respectively. Crop residues had more inhibitory effects on the Azerbaijan than Kermanshah population. Adaptive differentiation of C. platycarpos populations has also resulted in smaller seeds of the Azerbaijan compared with the Kermanshah population and resulted in higher emergence for Kermanshah population seedlings from greater soil depths. These results suggest that differences in germination requirements, drought and salinity tolerance of C. platycarpos populations are correlated with environmental conditions of the habitats of the studied populations.     

Seed germination and seedling emergence of Iberian starthistle (Centaurea iberica)

Centaurea iberica has become a problematic weed in some regions of western Iran. Little published data are available in the literature regarding its seed germination and seedling emergence. Therefore, this study was conducted in order to evaluate the effects of different factors on C. iberica seed germination. The highest level of germination of C. iberica was achieved at fluctuating temperatures of 15/25°C (night/day). The seed germination of C. iberica was stimulated by light and little germination occurred under continuous darkness. The pH solution did not have any effect on its seed germination. Centaurea iberica was tolerant to both salt and water stress. The level of seedling emergence was greatest for the seeds that were located on the soil surface, declining with depth, and no seedling emerged from a soil depth of 4 cm. These results indicated that C. iberica has the potential to infest more fields in the western parts of Iran, particularly rainfed areas. Based on the results of this study, crops with a dense canopy and/or planted in narrow‐row intervals could be used to diminish the seed germination of C iberica. In addition, the adoption of tillage systems that bury the seeds of C. iberica under the 4 cm depth would effective in its management.     

Correction to: The effect of a phytogenic feed additive (Digestrom P.E.P) on growth performance,proximate composition,hematological and immunological indices of juvenile beluga sturgeon Huso huso

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