排序方式: 共有25条查询结果,搜索用时 15 毫秒
1.
Elnaz Mehdizadeh Aghdam Lena Mahmoudi Azar Abolfazl Barzegari Farrokh Karimi Majid Mesbahfar Naser Samadi Mohammad Saeid Hejazi 《Gene》2012
Oxidative stress occurs as a result of imbalance between generation and detoxification of reactive oxygen species (ROS). This kind of stress was rarely discussed in connection with foreign protein production in Escherichia coli. Relation between cytoplasmic recombinant protein expression with H2O2 concentration and catalase activity variation was already reported. The periplasmic space of E. coli has different oxidative environment in relative to cytoplasm and there are some benefits in periplasmic expression of recombinant proteins. In this study, hydrogen peroxide concentration and catalase activity following periplasmic expression of mouse IL-4 were measured in E. coli. After construction of pET2mIL4 plasmid, the expression of recombinant mouse interleukin-4 (mIL-4) was confirmed. Then, the H2O2 concentration and catalase activity variation in the cells were studied in exponential and stationary phases at various ODs and were compared to those of wild type cells and empty vector transformed cells. It was revealed that empty vector introduction and periplasmic recombinant protein expression increased significantly the H2O2 concentration of the cells. However, the H2O2 concentration in mIL-4 expressing cells was significantly higher than its concentration in empty vector transformed cells, demonstrating more effects of recombinant mIL-4 expression on H2O2 elevation. Likewise, although catalase activity was reduced in foreign DNA introduced cells, it was more lowered following expression of recombinant proteins. Correlation between H2O2 concentration elevation and catalase activity reduction with cell growth depletion is also demonstrated. It was also found that recombinant protein expression results in cell size increase. 相似文献
2.
Rezaei MA Abdolmaleki P Karami Z Asadabadi EB Sherafat MA Abrishami-Moghaddam H Fadaie M Forouzanfar M 《Journal of theoretical biology》2008,254(4):817-820
In this study, membrane proteins were classified using the information hidden in their sequences. It was achieved by applying the wavelet analysis to the sequences and consequently extracting several features, each of them revealing a proportion of the information content present in the sequence. The resultant features were made normalized and subsequently fed into a cascaded model developed in order to reduce the effect of the existing bias in the dataset, rising from the difference in size of the membrane protein classes. The results indicate an improvement in prediction accuracy of the model in comparison with similar works. The application of the presented model can be extended to other fields of structural biology due to its efficiency, simplicity and flexibility. 相似文献
3.
Abolfazl Barzegari Mohammad Nouri Virginie Gueguen Nazli Saeedi Graciela Pavon-Djavid Yadollah Omidi 《Journal of cellular physiology》2020,235(7-8):5628-5636
The cell therapy of damaged tissue, which is linked to hypoxia condition might fail, in large part due to the emergence of oxidative stress (OS) and/or mitochondrial dysfunctions. Thus, the invigoration of stem cells against oxidative stress could be a reliable strategy to improve the cell therapy outcome. Of various antioxidants, mito-Tempo (mito-T) is one of the potent antioxidants that could target and neutralize the mitochondrial oxidative stress. In this study, for the induction of hypoxia and oxidative stress in mitochondria of the mesenchymal stem cells (MSCs) isolated from human adipose tissue, antimycin A (AMA) was used and then several parameters were analyzed, including cell viability and cell cycle arrest of MSCs exposed to AMA, mito-T, antioxidant potential, redox homeostasis, and signaling pathways in MSCs under oxidative stress. Based on our findings, the treated MSCs were found to impose a high resistance to the OS-induced apoptosis, which correlated with the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway required to manage OS. Upon exposure of the MSCs to high oxidative stress conditions using AMA, the cells failed to scavenge. The use of mito-T was found to alleviate the damage induced by oxidative stress through both direct functions of the free radical scavenging and the interplay in terms of cell signaling pathways including the upregulation of the Nrf2 pathway. These findings may pave the way in the stem cell therapy for the hypoxia-mediated tissue damage. 相似文献
4.
5.
Jahandideh S Abdolmaleki P Jahandideh M Barzegari Asadabadi E 《Journal of theoretical biology》2007,246(1):159-166
A systematic analysis compared sequence and structural parameters distributions between 13 pairs of psychrophilic and mesophilic proteins for elucidating the cold adaptation parameters. The results of statistical test (t-test) revealed that helical content, tight turn content, disulfide bonds and hydrogen bonds do not show significant difference between psychrophilic and mesophilic proteins. However, it was demonstrated in this study that a larger proportion of open beta-turn in psychrophilic proteins is an effective parameter in specific activity at low temperature. In addition, substitution of amino acids of charged and aliphatic groups with amino acids of tiny and small groups in protein chains, tight turns and alpha-helices in the direction from mesophilic to psychrophilic proteins is one of the mechanisms of low temperature adaptation. Such sequence and structural parameter differences would help to develop a strategy for designing cold-adapted proteins. 相似文献
6.
It is now well known that genetic and environmental factors affect the intestinal microbiome in an individual's lifetime and thus, different individuals possess different intestinal microbiomes and microbial metabolomes. The intestinal microbiome has been shown to differ among individuals from the same sex, between sexes and between individuals of different ages. Different families and, from a larger perspective, different communities, possess different microbiomes, and thus corresponding metagenomes. Therefore, it can be deduced that each individual human being can be characterized by his/her own intestinal microbial fingerprint. This understanding may prove helpful in future individualized medicine. These microorganisms are natural beneficial symbionts of the GI tract, have adapted to their human host over million years of coevolution and are now regarded as the second human genome. The difference in intestinal microbiome of different populations may explain why the results from different clinical trials on probiotic efficacy do not match with each other. People pay much, but they benefit little. In this article, it is recommended to isolate probiotics from natives' microbiomes and in the interest of efficacy, to use them in the same population. This line of thought can be considered in future guidelines from the Food and Agriculture Organization and the WHO on evaluation of probiotics in foods. 相似文献
7.
Jahandideh M Barkooie SM Jahandideh S Abdolmaleki P Movahedi MM Hoseini S Asadabadi EB Jouni FJ Karami Z Firoozabadi NH 《Journal of theoretical biology》2008,255(1):113-118
To investigate the role of the critical parameters in adaptation of proteins to low temperatures, a comparative systematic analysis was performed. Several parameters were proposed to have contribution to cold adaptation of proteins. Among proposed parameters, total values of residual structure states, secondary structure states and oligomeric states were alike in both psychrophilic and mesophilic proteins. In addition, our results provided new quantitative information about the trends in the substitution preference of Ile, Phe, Tyr, Lys, Arg, His, Glu and Leu with most of amino acids and substitution avoidance of Gly, Thr and Ala with most of amino acids. These findings would help future efforts propose a strategy for designing psychrophilic proteins. 相似文献
8.
Mohammad Ali Ghaffari Majid Zeinali Ebrahim Barzegari Asadabadi 《Journal of biomolecular structure & dynamics》2013,31(12):1919-1928
Human epidermal growth factor receptor 2 (HER2) contributes to the development of breast cancers and malignancies. On the other hand, engineered affibody Z(HER2:342) that binds to HER2 can be successfully used for both diagnostic purposes and specific ablation of malignant HER2-positive cell lines. In the current study, electrostatics-based prediction was applied for improving Z(HER2:342) binding affinity using computational design. The affibody Z(HER2:342) alone and in complex with HER2 was energetically minimized, solvated in explicit water, and neutralized. After heating and equilibration steps, the system was studied by isothermal-isobaric (NPT) MD simulation. According to trajectories, Z(HER2:342) specifically binds to HER2 through hydrogen bonds and salt bridges. Based on the electrostatic binding contributions, two affinity-matured variants namely V1 (Tyr35Arg) and V2 (Asn6Asp and Met9Glu) were rationally designed. More investigations through MD simulation show that V1 interacts with HER2 receptor more strongly, compared to Z(HER2:342) and V2. 相似文献
9.
Sina Atashpaz Sajjad Khani Abolfazl Barzegari Jaleh Barar Sepideh Zununi Vahed Reza Azarbaijani Yadollah Omidi 《Microbiology》2010,79(4):538-542
The intactness of DNA is the keystone of genome-based clinical investigations, where rapid molecular detection of life-threatening
bacteria is largely dependent on the isolation of high-quality DNA. Various protocols have been so far developed for genomic
DNA isolation from bacteria, most of which have been claimed to be reproducible with relatively good yields of high-quality
DNA. Nonetheless, they are not fully applicable to various types of bacteria, their processing cost is relatively high, and
some toxic reagents are used. The routine protocols for DNA extraction appear to be sensitive to species diversity, and may
fail to produce high-quality DNA from different species. Such protocols remain time-consuming and tedious, thus to resolve
some of these impediments, we report development of a very simple, rapid, and high-throughput protocol for extracting of high-quality
DNA from different bacterial species. Based upon our protocol, interfering phenolic compounds were removed from extraction
using polyvinylpyrrolidone (PVP) and RNA contamination was precipitated using LiCl. The UV spectrophotometry and gel electrophoresis
analysis resulted in high A
260/A
280 ratio (>1.8) with high intactness of DNA. Subsequent evaluations were performed using some quality-dependent techniques (e.g.,
RAPD marker and restriction digestions). The isolated DNA from 9 different bacterial species confirmed the accuracy of this
protocol which requires no enzymatic processing and accordingly its low-cost making it an appropriate method for large-scale
DNA isolation from various bacterial species. 相似文献
10.
Abolfazl Barzegari Sepideh Zununi Vahed Sina Atashpaz Sajjad Khani Yadollah Omidi 《Molecular biology reports》2010,37(2):833-837
Various investigations have been so far performed for extraction of genomic DNA from plant tissues, in which the extracted
intact DNA can be exploited for a diverse range of biological studies. Extraction of high quality DNA from leathery plant
tissues (e.g., coniferous organs) appears to be a critical stage. Moreover, for some species such as Taxus trees, bioprocess engineering and biosynthesis of secondary metabolites (e.g., paclitaxel) is a crucial step due to the restrictions
associated with extinction of these species. However, extraction of intact genomic DNA from these plants still demands a rapid,
easy and efficient protocol. To pursue such aim, in the current work, we report on the development of a simple and highly
efficient method for the extraction of DNA from Taxus baccata. Based upon our protocol, interfering phenolic compounds were removed from extraction using polyvinylpyrrolidone and RNA
contamination was resolved using LiCl. By employing this method, high quality genomic DNA was successfully extracted from
leaves of T. baccata. The quality of extracted DNA was validated by various techniques such as RAPD marker, restriction digestions and pre-AFLP.
Upon our findings, we propose this simple method to be considered for extraction of DNA from leathery plant tissues. 相似文献