Showing 14 results for Hasannia
Volume 4, Issue 2 (9-2013)
Abstract
One of the most promising strategies in cancer therapy is to induce apoptotic pathway. For this purpose, several constructed agonists of Death Receptor 5 (DR5) are in clinical development. Extrinsic and intrinsic apoptosis pathways of various cancer cells are primarily induced through the activation of the proapoptotic DR5. The extracellular domain of DR5 is comprised of several functional domains, among them the cysteine-rich domains (CRDs) play a critical role in TRAIL-DR5-mediated apoptosis. It has recently been shown that the binding of agonistic monoclonal antibody to another N-terminal domain of DR5 could mediate its activation and apoptosis induction. Variable domains derived from heavy chain antibodies (hcAb) called VHHs or nanobodies are robust, efficient and smallest antigen binding fragments. These unique features of VHHs make them potential therapeutic and diagnostic candidates. In the present study, using phage display technology, a library containing VHH genes was generated of an immunized camel with hapten-peptide 1ITQQDLAPQQRA12 and used to isolate the binders of this peptide. Through screening the phage library, three binders with high binding ability to desired epitope in the NTR region were obtained. Considering to the key role of this epitope in apoptosis inducing, these selected binders could be potential candidates to trigger apoptosis in various cancer cells.
Volume 5, Issue 1 (11-2014)
Abstract
Regarding the importance of inhibiting VEGF and unique features of VHHs as a new generation of antibody-based therapeutics, the present study aimed to generate VHHs against the receptor binding domain of VEGF, thereby blocking of VEGF binding to its receptor. After preparing the gene repertoire of VHH fragments from an immunized camel, a VHH phage display library was constructed. We adopted a stringent successive biopanning to isolate the phages displaying VHH with high affinity to VEGF-RBD.A significant enrichment of phages that specifically bound to the target protein was obtained after six rounds of panning. Of the specific clones with high binding affinity screened by monoclonal phage ELISA, 52% shared the same VHH sequence, showing its high enrichment. Using molecular simulation of antigen-antibody interaction based on the crystallographic information of VEGF/VEGFR2, molecular dynamics simulations and MM/PBSA free energy calculations, we provide a reliable picture of the binding site of antibody on antigen. The key residues in the VEvhh1-VEGF interface were dissected and the energetics was analyzed by MM/PBSA. The results of studies revealed that VEvhh1 binds to the receptor binding site of VEGF with high binding energy and showed the highest affinity to the residues of VEGF which are responsible for VEGF binding to VEGFR2. Also the antibody potently covers these key functional residues of VEGF, thereby inhibiting VEGF binding to its receptor and probably abrogating its biological activity. This study may represent VEvhh1 as an anti-VEGF and anti-angiogenic candidate.
Volume 7, Issue 1 (Winter 2019)
Abstract
Aims: Green algae (Chlorophyta), as a diverse group of algae, has almost omnipresent distribution in the Caspian Sea and plays an important role in ecosystem functioning. The aim of this study was to investigate the spatial and temporal distribution and biomass trend of planktonic green microalgae (Chlorophyta) in southeast of the Caspian Sea.
Materials & Methods: This experimental study was performed by sampling water from south of the Caspian Sea in Mazandaran province during the winter 2015 and summer 2016. Water sampling was done along two half-lines perpendicular to the estuaries of "Tajan" and "Babolrood" rivers in 8 stations and 4 depths (less than 1, 5, 10, and 20 m) in the euphotic zone, at 8 stations along the linear transects. Settlement method was applied to the preserved samples in formaldehyde 4%, in order to the qualitative and quantitative analysis of phytoplankton. The biomass of Chlorophyta was calculated, using the geometric shape method. The data were statistically analyzed, using PRIMER 6 and SPSS 19 software and the diagrams were drawn by Excel 2013.
Findings: Of total 29 identified Chlorophyta species, 28 species were present in the summer with the highest abundance of Chlorella sp. (1395×105±671×104 N/m3) and, 19 species were observed during the winter, with the highest abundance of Binuclearia sp. (456×105±155×104 N/m3). Binuclearia sp. also showed the highest biomass in both seasons.
Conclusion: The diversity of Chlorophyta is influenced by seasonal variations. Estuaries are the richest stations in terms of abundance and biomass of planktonic Chlorophyta in summer.
Volume 10, Issue 3 (Summer 2019)
Abstract
Bone morphogenetic proteins (BMPs) belong to the superfamily transforming growth factor-beta. These molecules play a role in fetal development and differentiation of different cells. In this regard, two homodimer molecules BMP-2 and BMP-7 play an important role in the formation of ectopic bone So that two types of recombinant form are available for ectopic use. After binding of the homodimer BMP-2 to its receptor at the cell surface, the accumulation of homodimers of type I and II receptors results in a biological response within the cell. Despite the existence of recombinant types of BMP-2 and BMP-7 due to the dangers of their use, the strategy of using monoclonal antibodies to trap endogenous types is still a priority in research programs. Instead of using monoclonal antibodies, the alternative method is to use the natural receptors of the ligand in the body. In this regard, due to the proper Kd binding of the ectodomain component of the receptor II of the BMP molecule in this project, the expression and purification of this part were attempted to trap BMP-2 endogenous. The protein component of the type II receptor ectodomain was expressed and purified by the bacterial host, which, by evaluating CD, of this recombinant protein showed a similar structure to that of the natural type. Also, its binding to the BMP-2 ligand with ELISA was evaluated and then calculated as Kd. Based on the results, the type II receptor ectodomain can be connected to the BMP-2 with a suitable binding property at the nM concentration, and in subsequent studies, it can be used as an alternative to a monoclonal antibody to Trap endogenous BMP molecules.
Volume 10, Issue 3 (Summer 2019)
Abstract
CEL I endonuclease pertaining to the S1 endonuclease family. The enzyme, with its high specificity, has the ability to identify different types of mutations and base replacement in the DNA molecule, which makes it important in commercial products to use in research and clinical laboratories. Although the enzyme exists in the celery plant, the extraction of the enzyme is a time-consuming process and not economical and the yield of the final product is low. In addition, due to its post-translational modifications to achieve the final active structure, no report has published to indicate the expression of the active form of this enzyme in the bacterial hosts yet. Therefore, one of the production sources of the active form of this enzyme is its cloning and expression in eukaryotic hosts, including yeast and mammalian cell lines. In this study, in order to express CEL I endonuclease, its gene sequence was optimized and synthesized in host eukaryotic HEK293T. CEL I was subcloned by double digest with KpnI and XhoI enzymes in the pBudCE4.1expression vector. The expression construct was transfected into the HEK293T cell line by lipofectamine transfection. Expression of the recombinant protein after transfection into HEK293T cells was confirmed by multiple methods including polyacrylamide gel electrophoresis, ELISA, RT-PCR, and western blot reaction. The analysis of SDS-PAGE and western blot data confirmed the molecular weight of approximately 30kDa. Purification was carried out with the Ni-NTA column and the amount of purified protein was determined to be about 0.2mg/ml. Finally, the activity of endonuclease enzyme was investigated on both normal and mutated heteroduplex DNA amplified by PCR. The results showed that the expression of this protein in HEK293T host had shown sufficient activity.
Volume 10, Issue 4 (Fall 2019)
Abstract
Introduction: Nowadays, bone tissue repair with increasing bone disorders and injuries have special importance. Bone tissue engineering provided specific solutions to these problems. The present study was conducted with the aim of purification of recombinant fusion peptide containing hydroxyapatite affinity tag using the ceramic chromatography column.
Material & methods: In this study, a fusion peptide was designed which at one side comprised the heparin-binding domain sequence, which can be attached to various types of growth factors involved in tissue repair and entrap these factors at the site of the lesion. On the other side, it contained a tag, which included a sequence derived from a laboratory study based on phage expression. The reason for keeping the sequence of this tag is to attach the peptide to the scaffold containing hydroxyapatite and purifying the recombinant peptide by the hydroxyapatite column. Therefore, the gene sequence was optimized and synthesized for expression in the prokaryotic host of E.coli strain BL21. Then the gene sequence was subcloned by double digestion with the SacI and BamHI enzymes into the expression vector of pET-21a(+). The expression of the recombinant peptide was investigated by SDS-PAGE and western blot. In order to optimize the purification conditions, two-step purification was carried out by applying fundamental changes in the main work method of the manufacturer company and was purified with acceptable purity. Finally, the existence of peptide assemblies was investigated by the SLD method.
Finding: The results of PCR cloning, enzymatic digestion using SacI and BamHI enzymes and sequencing indicated the accuracy of the cloning process. On the other hand, expression of the fusion peptide was confirmed by SDS-PAGE and Western blot techniques, and its migration onto the gel resulted in a band cleavage of about 12 kDa. Changes made to the manufacturer's workflow allowed the purification process to be optimized and the results of the DLS method showed the purity of the purified peptide.
Conclusion: The results indicate the desirable expression and remarkable purity of the fusion peptide designed in this study.
Volume 11, Issue 3 (Summer 2020)
Abstract
Fibrinogen is a major component of the coagulation cascade following tissue damage and rapidly forms an insoluble fibrin scaffold. Fibrin is a filamentous biopolymer that naturally forms from fibrinogen polymerization during blood clotting. After tissue damage and coagulation cascade initiation, soluble fibrinogen polymerization by thrombin enzymebegins and forms an insoluble fibrin network and blood clots with platelets. This fibrin network is crucial for the development of homeostasis after tissue damage. This biopolymer also plays a key role in the wound healing as a temporary scaffoldand due to its unique structural properties and physiological function; it is used in reconstructive medicine. Fibrin is able to absorb extracellular matrix proteins (ECM) such as fibronectin and growth factors. The main types of fibrin scaffolds like platelet-rich fibrin (PRF) and platelet-rich plasma (PRP) are being used as autologous biomaterials in reconstructive medicine, wound healing, orthopedics and skin reconstruction and cosmetic sciences. Fibrin derivatives and degradation products also play an important role in the process of wound healing by stimulating cell infiltration and tissue regeneration and they are being widely used in developing new products as a biological material for over a century.
Volume 11, Issue 3 (Summer 2020)
Abstract
Human alpha1-antitrypsin is a glycoprotein comprised of 394 amino acids and 52 kDa molecular weight, which is mostly synthesized and secreted by hepatocytes, diffuses to interstitial lung tissues, and has an essential function to protected tissues against neutrophil elastase. One of the significant challenges in dealing with alpha-1-antitrypsin is the structural instability of the folded form of protein and, consequently, the accumulation of polymers in lung tissue. This makes patients vulnerable to chronic obstructive pulmonary disease, severe asthma, and emphysema. Intravenous augmentation therapy of alpha 1-antitrypsin is one of the most prevalent therapies. Moreover, patients who are candidates for that have respiratory symptoms, and the use of bronchodilator (Salbutamol) is the first recommended standard treatment. In this study, protein purification was performed by using high-performance affinity chromatography and, its purity was confirmed by gel electrophoresis. The effect of different concentrations of salbutamol on heat-induced polymerization at 60 ° C was investigated by non-denaturing polyacrylamide gel electrophoresis, dynamic light scattering (DLS), and circular dichroism (CD) techniques. Protein activity was measured by trypsin inhibitor capacity (TIC) assay. The results indicated that salbutamol decreases the rate of polymerization by reducing the flexibility of the reactive center loop, thus decelerate protein activity reduction. Therefore, salbutamol can be an appropriate supplementary for alpha 1-antitrypsin and a proper option for the treatment of protein polymerization associated diseases.
Volume 12, Issue 4 (fall 2021)
Abstract
Bone morphogenetic proteins (BMPs) are a subfamily of multifunctional superfamily transforming growth factor-beta (TGF-β), thus they have a lot of similarity in biosynthesis, structure, signaling and biological function with other members of the superfamily. They are involved in growth and differentiation of embryo to maintenance of adult cells. Among this family member, BMP-2 is a valuable protein that acts in different processes such as spinal fusions, articular cartilage damage therapy, tumor inhibition, gingivitis and dental treatment. The high importance of this protein and its low production rate in body caused several researches in the field of producing recombinant BMP-2 in different hosts. Recombinant production of the protein in bacterial host caused the decrease in production costs and therefore led to the common use of BMP-2 in treatment of various diseases. To date, positive effects of intact BMP-2 and its derivative peptides, in order to osteoinduction in fracture treatment and jaw bone regeneration for dental implantation, were considerable. Considering high clinical significance of BMP-2, there is a necessity for more investigations in relation to this protein.
Volume 15, Issue 1 (3-2023)
Abstract
Abstract
The wound healing process is a complex and dynamic process that involves many metabolic pathways. This process consists of three phases inflammation, cell proliferation, and tissue regeneration stages. Successful wound healing depends on careful regulation and coordination between the factors involved. Until recent years, the strategy of treating chronic wounds was limited to wound preparation, removal of necrotic tissue, and control of infection and inflammation, but recently the use of growth factors has been approved to accelerate the healing process and heal the wound. Human recombinant growth factor PDGF-BB is one of the first types of recombinant growth factors approved in treating diabetic wounds. Several studies have reported that PDGF is an important mediator in wound healing that helps to accelerate healing, improve inflammation, cell proliferation, angiogenesis, and tissue regeneration. In this study, the human PDGF-B gene sequence was inserted into the pET 21a (+) expression vector for cloning and then inserted under the T7 promoter for its expression in the E. coli shuffle host. Purification was done using a nickel agarose column and to check the activity of the purified protein, cell proliferation, migration, and interaction were checked. The results of this study showed that the dimer type of PDGF expressed and purified in the bacterial host, probably due to maintaining the correct folded structure, has both main activities, i.e., cell proliferation due to the active binding to the cell receptor, as well as the ability to bind to fibrinogen.
Volume 15, Issue 3 (Autumn 2015 2015)
Abstract
Since various economic sectors, in particular housing sector, need to bank loans, the variations in lending behavior of banks due to changes in key economic variables may jeopardize the sound economic activities. In this study the lending behavior of Bank Maskan of Iran was modeled by a Vector Auto-regression (VAR) model during 1991-2011. The results of long run Vector Error Correction Model (VECM) indicated that the broad money supply, inflation rate and stock price fluctuations have indirect effects on lending behavior of Bank Maskan, however the effect of exchange rate variations is positive. In addition, the results of short run VECM showed that variations in the broad money supply have direct effects on lending behavior of Bank Maskan, but inflation rate, exchange rate and stock price fluctuations have no significant effects.
Abbas Hasanniah, Mojtaba Movahedi,
Volume 17, Issue 12 (2-2018)
Abstract
The 5052 aluminum alloy was lap joined to Al-1050 clad steel sheet (with Al-1050 thickness of 1mm) using gas tungsten arc welding (GTAW) process with 4047 Al-Si filler metal at the welding currents of 80, 100 and 120 A. Effect of welding current was studied on the weld microstructure, intermetallic compounds layer and tensile strength of the joints. Microstructural studies were done using optical and scanning electron microscopes (SEM) equipped with energy dispersive spectroscopy (EDS) and tensile strength of the joints was determined by shear-tensile test. Results shows that the reaction layer included two Al3Fe and Al5Fe2 intermetallic phases formed at the interface of the St-12 base sheet and Al-1050 clad layer. Maximum average thickness of the reaction layer was ~3.5 µm .It seems that presence of Al-1050 layer prevents excessive growth of Al-Fe intermetallic layer. The joint tensile strength decreased almost linearly by enhancement of the welding current and the primary α-Al dendrite arm spacing increased and Al-Si eutectics were distributed more uniformly. As a result, the crack easily grows and fracture force reduces. The maximum tensile strength of the joints reached to ~190 MPa, i.e. ~80% of 5052-H34 aluminum base metal strength. During the shear-tensile test, fracture in all the joints was started from the root of the weld and then propagated inside the weld metal with an angle of ~70 with respect to the Al-1050 base sheet. Stress analysis in weld showed that fracture in the joint was controlled predominantly by the maximum normal stress.
S. Ghorbanzadeh , M. Nazari , M.m. Shahmardan , A. Hasannia, M. Nazari ,
Volume 19, Issue 4 (April 2019)
Abstract
In this paper, heat transfer and magnetic fields in a vacuum induction melting furnace have been studied numerically. To solve the coupled equations of thermal and magnetic induction heating, the finite element method has been used. An induction furnace model is simulated using an industrial geometry. The studies indicate that the effect of the geometry of the crucible and the coil on the melting time has not been thoroughly investigated and requires more in-depth studies. It is attempted to improve the shape of the induction furnace, so that in less time aluminum is melted in a small scale furnace. The effect of the diameter-to-height ratio of the crucible on the duration of melting has been investigated. By decreasing the diameter-to-height ratio, the temperature reaches melting temperature in a shorter time. The results show that for the diameter-to-height ratio of less than 0.4, there will not be a significant change at the average temperature. 10% reduction in the distance between the coils leads to an increase in the average temperature of the working material inside the furnace. With considering the constant density of the coil current and the constant induced current in the heated material, the effects of the number of coil turns on the temperature distribution and magnetic flux are investigated. In this way, the accuracy of the model is also checked by induction heating concepts. The effect of frequency on temperature has been investigated in different coil lengths. The results show that an increase of 4 times in the frequency caused an increase of 1.7 times in the average temperature.
Volume 19, Issue 133 (February 2023)
Abstract
Non-uniform drying and head rice reduction due to non-movement of paddy in common fixed bed dryers is one of the basic problems in rice milling factories. In order to investigate and provide a suitable drying method with the approach of creating uniformity in drying process, reducing losses, and saving energy consumption, a two factorial experiment in completely randomized design (CRD) was used. The factors were the initial moisture content (IMF) of paddy at two levels (16 and 18%) and drying method at 4 levels (one-way air flow, reverse air flow in 1 hour, 2 hours and 3 hours and then continuation of drying process the same as one-way airflow). The same drying air temperature and air velocity was considered for all treatments. In both moisture treatments, three hours reverse air flow drying has the highest head rice (75.7-75.86%) and the lowest energy consumption (41-49 MJ/kg water). The highest energy consumption with the amount of 79 and 67 MJ/kg water was belonging to the paddy with high and low IMC, respectively. In one way airflow, dried paddy in 10 cm from the bottom layers of dryer has the lowest amount of head rice (63.65%). In both moisture treatments, the results of mixed layers showed that one hour reverse air flow drying with values of 68.28-68.68% had the lowest head rice. Also, drying method had no significant effect (P>0.05) on the cooking quality.
