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51.
Electrochemical studies of DNA immobilization onto the azide-terminated monolayers and its interaction with taxol 总被引:2,自引:0,他引:2
Mehdinia A Habib Kazemi S Zahra Bathaie S Alizadeh A Shamsipur M Mousavi MF 《Analytical biochemistry》2008,375(2):331-338
A surface modification procedure for the creation of self-assembled monolayers (SAMs) that can be used as a scaffold for double-stranded DNA (dsDNA) incorporation onto the gold surfaces is described. The SAMs of an azidohexane thiol derivative were prepared on the Au electrode and then used for the immobilization of dsDNA. The electrochemical characteristics of dsDNA onto the SAM-modified gold electrode were investigated by cyclic voltammetry and electrochemical impedance spectroscopy, and the surface concentration of dsDNA onto the SAMs surface was estimated. The interaction of dsDNA with the anticancer drug, taxol (paclitaxel), was also studied on the surface of DNA/SAM/Au electrode. The observed decrease in the guanine oxidation peak current was used to monitor the interaction of taxol with DNA. The resulting Langmuir isotherm for taxol binding to DNA at the modified electrode was used to evaluate the binding constant of taxol-DNA. The results obtained supported the groove binding interaction of taxol with DNA. The modified electrode was used as a sensitive sensor for quantification of taxol in human serum sample. 相似文献
52.
Establishment and in vitro differentiation of a new embryonic stem cell line from human blastocyst 总被引:10,自引:0,他引:10
Baharvand H Ashtiani SK Valojerdi MR Shahverdi A Taee A Sabour D 《Differentiation; research in biological diversity》2004,72(5):224-229
Embryonic stem cells have the ability to remain undifferentiated and proliferate indefinitely in vitro while maintaining the potential to differentiate into derivatives of all three embryonic germ layers. These cells have, therefore, potential for in vitro differentiation studies, gene function, and so on. The aim of this study was to produce a human embryonic stem cell line. An inner cell mass of a human blastocyst was separated and cultured on mouse embryonic fibroblasts in embryonic stem cell medium with related additives. The established line was evaluated by morphology; passaging; freezing and thawing; alkaline phosphatase; Oct-4 expression; anti-surface markers including Tra-1-60 and Tra-1-81; and karyotype and spontaneous differentiation. Differentiated cardiomyocytes and neurons were evaluated by transmission electron microscopy and immunocytochemistry. Here, we report the derivation of a new embryonic stem cell line (Royan H1) from a human blastocyst that remains undifferentiated in morphology during continuous passaging for more than 30 passages, maintains a normal XX karyotype, is viable after freezing and thawing, and expresses alkaline phosphatase, Oct-4, Tra-1-60, and Tra-1-81. These cells remain undifferentiated when grown on mouse embryonic fibroblast feeder layers in the presence or absence of recombinant human leukemia inhibitory factor. Royan H1 cells can differentiate in vitro in the absence of feeder cells and can produce embryoid bodies that can further differentiate into beating cardiomyocytes as well as neurons. These results define Royan H1 cells as a new human embryonic stem cell line. 相似文献
53.
Glutamic acid is an excitatory neurotransmitter that may have a significant role in the central chemical drive of ventilation. Therefore cardiorespiratory function was measured in pentobarbital sodium-anesthetized dogs before and after central inhibition of glutamate metabolism by means of methionine sulfoximine (MSO), a specific inhibitor of glutamine synthase (GS) catalyzing amidation of glutamate to glutamine. GS was inhibited centrally by perfusing the ventriculocisternal space with artificial cerebrospinal fluid (CSF) containing 92.5 mmol MSO per liter at a fixed pH, perfusion rate, and pressure. After GS inhibition, CSF transfer rate of [13N]glutamine synthesized from 13NH4+ amidation of glutamate was reduced five-fold, and minute ventilation increased from 2.90 +/- 0.41 (SE) l/min (0.164 +/- 0.020 l.min-1.kg body wt-1) to 4.46 +/- 0.52 l/min (0.254 +/- 0.029 l.min-1.kg body wt-1). This increase in ventilation with endogenous glutamate and the increase in ventilation previously observed during ventriculocisternal perfusion of exogenous glutamate are compared quantitatively via a model of central neurotransmitter glutamate chemoreception. The results support the hypothesis that the endogenous brain glutamate is important in the central chemical drive of ventilation. 相似文献
54.
55.
Faegheh Kazemi Seyed Shahriar Arab Nasir Mohajel Malihe Keramati Niloofar Niknam Mohammad Mehdi Aslani 《Journal of biomolecular structure & dynamics》2019,37(8):1944-1955
Streptokinase (SK), a plasminogen activator (PA) that converts inactive plasminogen (Pg) to plasmin (Pm), is a protein secreted by groups A, C, and G streptococci (GAS, GCS, and GGS, respectively), with high sequence divergence and functional heterogeneity. While roles of some residual changes in altered SK functionality are shown, the underlying structural mechanisms are less known. Herein, using computational approaches, we analyzed the conformational basis for the increased activity of SK from a GGS (SKG132) isolate with four natural residual substitutions (Ile33Phe, Arg45Gln, Asn228Lys, Phe287Ile) compared to the standard GCS (SKC). Using the crystal structure of SK.Pm catalytic complex as main template SKC.μPm catalytic complex was modeled through homology modeling process and validated by several online validation servers. Subsequently, SKG132.μPm structure was constructed by altering the corresponding residual substitutions. Results of three independent MD simulations showed increased RMSF values for SKG132.μPm, indicating the enhanced structural flexibility compared to SKC.μPm, specially in 170 and 250 loops and three regions: R1 (149–161), R2 (182–215) and R3 (224–229). In parallel, the average number of Hydrogen bonds in 170 loop, R2 and R3 (especially for Asn228Lys) of SKG132 compared to that of the SKC was decreased. Accordingly, residue interaction networks (RINs) analyses indicated that Asn228Lys might induce more level of structural flexibility by generation of free Lys256, while Phe287Ile and Ile33Phe enhanced the stabilization of the SKG132.μPm catalytic complex. These results denoted the potential role of the optimal dynamic state and stabilized catalytic complex for increased PA potencies of SK as a thrombolytic drug. 相似文献
56.
Human embryonic stem cells (hESC) represent a population of undifferentiated pluripotent cells with both self-renewal and multilineage differentiation characteristics. Proteomics provides a powerful approach for studying the characteristics of hESC and discovering molecular markers. We have analyzed proteome profiles of three hESC lines using 2-DE and MALDI TOF-TOF. Out of 844 spots analyzed with MALDI TOF-TOF, 685 proteins were identified of which 60 proteins were classified as the most abundant proteins on 2-D gels. A large number of proteins particularly high abundant ones were identified as chaperones, heat shock proteins, ubiquitin/proteasome, and oxidative stress responsive proteins underscoring the ability of these cells to resist oxidative stress and increase the life span. Several proteins involved in cell proliferation and differentiation were also among the highly expressed proteins. Although overall expression pattern of three hESC were similar, 54 spots changed quantitatively and 14 spots changed qualitatively among the hESC cell lines. Most of these proteins were identified as proteins involved in cell growth, metabolism and signal transduction, which may affect the self-renewal and pluripotency. To our knowledge, this study represents the first proteomic dataset for hESC and provides a better insight into the biology of hESC. Proteome maps of hESC are accessible at http://www.RoyanProteomics.ir. 相似文献
57.
Immune checkpoints in hematologic malignancies: What made the immune cells and clinicians exhausted!
Abbas Hajifathali Sayeh Parkhideh Mohammad H. Kazemi Rouzbeh Chegeni Elham Roshandel Majid Gholizadeh 《Journal of cellular physiology》2020,235(12):9080-9097
Hematologic malignancies comprise a considerable part of cancers with high mortality at any age. Since the introduction of hematopoietic stem cell transplantation (HSCT), the overall survival of patients dramatically increased. The main goal of HSCT is the induction of a graft-versus-leukemia effect to eradicate the residual cancer cells and also reconstitute a healthy immune system for patients. However, relapse is a nettlesome challenge of HSCT. Like many other tumors, hematologic cancer cells induce immune exhaustion leading to immune escape and relapses after HSCT. Besides malignant cells, inhibitory cells such as tumor-associated macrophages and myeloid-derived suppressor cells express various inhibitory receptors capable of inducing exhaustion in immune cells, especially T and natural killer cells. The significance of immune checkpoint blocking in tumor regression in clinical trials led to the 2018 Nobel Prize in Physiology/Medicine. Here, we reviewed the clinical roles of immune checkpoints in hematologic malignancies and post-HSCT relapses. 相似文献
58.
59.
Shen DK Noodeh AD Kazemi A Grillot R Robson G Brugère JF 《FEMS microbiology letters》2004,241(1):87-93
The phospholipase B family (PLB) are enzymes sharing phospholipase (PL), lysophospholipase (LPL) and lysophospholipase-transacylase (LPTA) activities. They have been shown to be important virulence factors in several human fungal pathogens including Candida albicans and Cryptococcus neoformans. Aspergillus fumigatus, a human opportunistic fungal pathogen leading to a high rate of mortality in immunosuppressed patients is known to possess an extracellular phospholipase B activity. In this paper, we report the molecular characterisation of three PLB genes from A. fumigatus (afplb) using degenerate primers in PCR amplification and data from the A. fumigatus genome project. They are expressed at 37 degrees C, and two of them (afplb1 and afplb3) are induced by lecithin. They encode proteins of 633, 588 and 630 amino acids, respectively, presenting together a T-Coffee score of 81. They also possess the amino acid triad responsible for enzymatic activity in the mammalian cytosolic PLA2 and other fungal PLBs. AfPLB1 and afPLB3 are secreted with a cleaved signal peptide. The complete cDNA sequences were obtained by RACE-PCR for the two secreted afPLBs and probably account for the extracellular phospholipase activity previously reported in the culture media of A. fumigatus. 相似文献
60.
Maryam Kazemi Elahehnaz Parhizkar Soliman Mohammadi Samani Omidreza Firuzi Hossein Sadeghpour Fatemeh Ahmadi Ali Dehshahri 《Biotechnology progress》2023,39(2):e3310
Co-delivery of small chemotherapeutic molecules and nucleic acid materials via targeted carriers has attracted great attention for treatment of resistant tumors and reducing adverse effects. In this study, a targeted carrier for co-delivery was prepared based on low-molecular weight polyethylenimine (LMW PEI). Paclitaxel (PTX) was covalently conjugated onto PEI via a succinate linker. The PEI conjugate was decorated with L-DOPA in order to target large neutral amino acid transporter-1 (LAT-1) that is over-expressed on various cancer cells. This PEI conjugate was complexed with human ABCB1 shRNA plasmid to down-regulate the expression of P-glycoprotein, as one of the major efflux pumps inducing resistance against chemotherapeutics. The formation of PEI conjugate enhanced the solubility of PTX and resulted in the condensation and protection of plasmid DNA in nanosized polyplexes. The results of targeted delivery into the cells demonstrated that PEI conjugate transferred the payloads to the cells over-expressing LAT-1 transporter, while the biological effects on the cells lacking the transporter was negligible. Also, shRNA-mediated down-regulation of P-gp led to the increase of toxic effects on the cells over-expressing P-gp. This study suggests a promising approach for co-delivery of small molecules and nucleic acid materials in a targeted manner for cancer therapy. 相似文献