Showing 8 results for Hashempour
Zahra Hasanshahi, Behzad Dehghani, Tayebeh Hashempour,
Volume 13, Issue 3 (1-2023)
Abstract
Background:
HIV has at least six regulatory genes among which the Vif protein can control HIV replication. This study, as the first report, investigated the important mutations in VIF protein in sequences from Iranian patients and using immunoinformatics, conserved regions of this protein and B-Cell, T-Cell and CTL epitopes to stimulate the immune system, were determined.
Methods:
VIF sequences were obtained from NCBI GenBank, and tertiary structures, B-Cell, T-Cell and CTL epitopes were predicted by bioinformatics tools; besides, their antigenic and allergenic properties were studied.
Results:
The most prevalent mutations in Vif protein were related to S 49 P (90%), S 140 N and N 186 S (80%). Two substitutions at positions 41 and 42 were introduced which have effect on Vif binding to host factor. In addition, three regions were identified as the best epitope sequences with high potential to induce immune system and the lowest allergic properties, among which 5-32 region was suggested as the best vaccine candidate regions.
Conclusion:
This study as the first study from Iran using immunoinformatics tools to introduced a region with the high potential to induce humoral and cellular immune systems and lowest allergenic properties which can be used for further studies on HIV vaccines.
Volume 17, Issue 109 (March 2021)
Abstract
Oxalic acid (OA), as a natural antioxidant, delays the ripening and senescence of fruits. In this research, the effect of different concentration of OA (0, 2, 4, 6, and 8 mM) investigated on storage life and postharvest quality of loquat fruit at 5°C and 90±5% relative humidity for 28 days. Traits such as browning index, biochemical and qualitative characteristics and activity of polyphenol oxidase (PPO) and peroxidase (POD) enzymes of fruit at harvest (0), 7, 14, 21 and 28 days after storage were analyzed. With increasing storage time, the level of browning index, total soluble solids (TSS), ratio of TSS/titratable acidity (TA) and the activity of PPO and POD enzymes increased in all treatments, while firmness, ascorbic acid, total phenol and flavonoids content and antioxidant activity decreased (p˂0.05). OA application significantly reduced the level of browning index and the activity of enzymes responsible for tissue browning (PPO and POD) compared to control (p˂0.05). At the end of storage, fruits treated with different concentration of OA had a more firmness tissue and higher level of ascorbic acid, total phenol and flavonoids content and antioxidant activity in comparison to the control fruits (p˂0.05). Overall, OA application effectively reduced fruit softening and browning index with diminished the activity of PPO and POD enzymes during cold storage. Thus, OA treatment (6 mM) can be used as an effective method for cold storage of loquat fruit.
Volume 18, Issue 1 (5-2014)
Abstract
Appropriate methods for prediction of future trends in capital markets lead to a better decision making for market participants. Classic methods don not perform well in prediction of financial markets due to the nonlinear and chaotic nature of these markets. Moreover, information extracted from data disappear quickly, so these method are not workable in the long run.
The goal of this paper is using ant colony optimization algorithm for prediction of Tehran Stock Exchange's total return index (TEDPIX) data. First, we used the largest Lyapunov exponent to the consider chaotic nature of TEDPIX and then the ant colony optimization paradigm we employed to analyze topological structure of the attractor behind the given time series and to single out the typical sequences corresponding to the different parts of the attractor. The typical sequences were used to predict the time series values.
Eventually with respect to MSE , RMSE and MAE, ACO has lower error than GARCH and EGARCH models; however, Diebold Marino test shows that there is no difference if we use ACO or GARCH models for prediction; this represents that differences of error for different models in this article are very little. This article with detachment of typical sequences allows a structural method for prediction of chaotic data. So in prediction of data with many fluctuations and in long term, it can result to a better predictions. The algorithm of this paper is able to provide robust prognosis to the periods comparable with the horizon of prediction.
Keywords
Volume 18, Issue 120 (February 2021)
Abstract
In this study, qualitative traits and bioactive compounds of edible oil that extracted from three olive promising genotypes (T2, T7, and T18) and two cultivars (Zard and Koroneiki) from Tarom olive collection in Zanjan province were evaluated during two crop seasons (2017-2018). Edible oil quality traits including free fatty acids (FFA), peroxide value (PV) and extinction coefficients (K232 and K270), total chlorophyll, total carotenoids, total phenols, total flavonoids and antioxidant capacity were measured. The results of analysis of variance of year Í cultivar / genotype on oil qualitative traits showed that their interactions on all traits except K270 were significant at 1% probability level. The results showed that edible oil of T7 genotype (0.79% as oleic acid) and Zard cultivar (0.43% as oleic acid) in 1997 had the lowest and highest FFA contents, respectively. Edible oil of T7 in 2018 (17.22 m Eq / kg of oil) and T2 in 2017 (96.67 m Eq / kg) showed the highest and lowest PV levels, respectively. The K232 extinction coefficient of T18 oil was the lowest in both years (0.8 and 1.03 for 2017 and 2018, respectively). Edible oil of Zard cultivar had the highest amount of total phenol in 2017 (243.94 mg gallic acid per kg of oil). T7 genotype had the highest amounts of total flavonoids in 2018 )21.45 mg of quercetin per kg of oil(. Koroneiki cultivar with 90.55% had the highest antioxidant capacity in 2017 and T7 genotype with 41.65% had the lowest value of this index. T2 genotype in both years in terms of antioxidant capacity was in a statistical group with commercial cultivars.
Volume 19, Issue 4 (9-2017)
Abstract
Objective: Melanoma differentiation association gene-7 (MDA-7)/IL24 is a tumor suppressor gene. The iNGR peptide sequence, with excellent tropism to surface integrins has been employed for targeting of therapeutic molecules toward tumor cells. The purpose of our study was to construct a plasmid expressing modified MDA-7 fused with an iNGR peptide for better targeting to tumor cells.
Methods: At first, we amplified the MDA-7 sequence by PCR, while the reverse primer contained the iNGR peptide sequence to add it to the end of a new MDA-7 gene. The resultant MDA7-iNGR and MDA-7 were cloned into a pCDNA3.1 eukaryotic expression vector. The accuracy of cloning methods, integrity of the plasmids, and sequence were sequentially evaluated by digestions, colony-PCR, and sequencing. The expressions of the plasmid constructs were assayed by ELISA following their transfection into Ad-293 cells. Next, the plasmids were transfected into Hep-G2 cells and their mRNA were converted to cDNA. We assessed the gene expression levels of Gadd153 and Bax. As the final step, apoptosis induction of Hep-G2 cells following transfection was evaluated by the help of PI/Annexin V staining according to flow cytometry.
Results: The results showed the integrity of construct backbone in addition to reading frame of the MDA-7-iNGR sequence. A suitable expression/secretion of modified the MDA-7.iNGR protein was detected by ELISA assay of the culture supernatant when compared to the control construct that expressed unmodified MDA-7. The viabilty test demonstrated no benefit for this kind of modification of the MDA-7 protein. Real-time PCR and flow cytometry analyses revealed that the addition of iNGR to MDA-7 caused a decrease in its apoptotic effect on hepatic tumor cells compared to the normal protein. The modified protein had significant apoptosis induction compared to the negative control group (P<0.01).
Conclusion:Although the new pCDNA/MDA-7.iNGR plasmid expressed iNGR-fused MDA-7 protein efficiently, it could not improve the natural apoptosis property of normal MDA-7.
Volume 19, Issue 126 (August 2022)
Abstract
In order to evaluate the effect of different preharvest fertilization methods on quantitative and qualitative characteristics of kiwifruit (var. Hayward) at postharvest stage, an experiment was conducted in a randomized complete block design with 8 treatments in four replications in Citrus and Sub-tropical Fruits Research Center during three crop years (2014- 2016). Fertilizer treatments included broadcast application (control), localized placement, strip, foliar, fertigation, broadcast application + foliar, fertigation + foliar and localized placement + foliar. Then in the first of November in each year, sampling of the treated fruits was carried out to measure the quantitative and qualitative characteristics of the fruit at postharvest stage during three years. Harvested fruits were kept cold storage at 0.5 ° C and 90% relative humidity for three months. The results showed, the fertilizer method had a significant effect on the fruits weight loss. So that the fruits fed by strip (6.08%), fertigation (6.74%) and combination of fertigation and foliar application (6.61 %) methods had less weight loss during cold storage, respectively. L * and chroma content of flesh were affected by the fertigation method. Result also showed that the control fruits had the lowest amount of antioxidant capacity and strip fertilization treatment had the highest antioxidant capacity during cold storage. Sensory attributes analysis showed that the amount of aroma, flavour, off-flavour, sweetness, sourness and overall fruit acceptability in fruits treated by broadcast application + foliar method obtained the most desirable scores.
Volume 23, Issue 1 (Winter 2020)
Abstract
Aims: No definitive treatment or effective vaccine has been suggested against the East Respiratory Syndrome Coronavirus (MERS-CoV) virus which indicates the growing importance of the study of this virus. Amongst all MERS proteins, glycoprotein S has always been the main candidate for vaccine research against this virus, due to its function and structure. The aim of the present study was to investigate the structural, functional, and immunological properties of S protein using bioinformatics software that paves the way for designing an effective vaccine against this virus.
Materials & Methods: 35 glycoprotein S sequences of MERS were obtained from Genbank and amino acid changes were investigated. In addition, sequences were analyzed by various software for post-translational changes. Five types of software were used to evaluate the immunologic and allergenic properties. Finally, different structural aspects of this protein were predicted by SOPMA software.
Findings: The highest prevalence substitutions were found in amino acids of 95, 123, and 696 and the results indicate that there are four B-cell epitopes in glycoprotein S, and this protein has been affected by post-translational changes, including glycosylation and phosphorylation. This protein has no allergenic properties and the majority of its structure contains Alpha helix.
Conclusion: Glycoprotein S, especially in the RBD region of S1, has a high potential to induce the host immune system and the other features mentioned protein make it appropriate for the production of recombinant protein, including stability in host cells. Therefore, the use of glycoprotein S, especially S1, is recommended as a suitable candidate for vaccine design.
Volume 23, Issue 2 (Spring 2020)
Abstract
Aims: Many inhibitors have been introduced for the treatment of HIV-1 infections; however, most of these efforts have been failed due to the presence of resistant strains. The purpose of the current study was to investigate the treatment-resistance mutations in the HIV virus integrase gene and the effect of these mutations on the structure, function, and physical and chemical properties of this enzyme using bioinformatics software.
Materials & Methods: 36 HIV-1 integrase sequences form Iranian patients were obtained from the NCBI Genbank. After determining the mutations compared to the reference sequence, its post-modification and physical and chemical properties were described. Sequences subtypes, as well as the second and third structures, and possible interactions of this enzyme with the main inhibitors of the integrase were examined.
Findings: The analysis of selected sequences indicated a number of mutations in this protein. The subtype of most of the samples was A1 and the results of the analysis of the interaction showed that the mutations in the samples had no significant effect on the interaction of inhibitors with the integrase enzyme.
Conclusion: The binding site of these inhibitors is often found in the catalytic domain of integrase enzyme, and the results of this study depicted that most mutations were located outside this region, and this may be the main reason for the failure of these mutations to affect the interaction of inhibitors and integrase enzyme. Generally, the findings of this study suggest that anti-HIV inhibitors of HIV-1 can be used as an effective way to control this disease for Iranian patients.