排序方式: 共有187条查询结果,搜索用时 15 毫秒
41.
Elham Abdolmajid Hasti Kharazi Mahfam Chalaki Marzieh Khojasteh Setareh Haghighat Farnoosh Attar 《Journal of biomolecular structure & dynamics》2019,37(11):3007-3017
This study is focused on the fabrication and characterization of titanium oxide (TiO2) NPs. Afterwards; the interaction of TiO2 NPs with human hemoglobin (Hb) was investigated by FTIR spectroscopy, fluorescence spectroscopy, and molecular docking studies. Also, the cytotoxic effect of fabricated TiO2 NPs against human white blood cells (WBCs) was considered by MTT assay. The antibacterial effect of synthesized NPs was examined on Pseudomonas aeruginosa (ATCC 27853); Escherichia coli (ATCC 25922) and Staphylococcus aureus (ATCC 25923). TEM and DLS investigations showed that the synthesized TiO2 NPs have a narrow nano-sized distribution. XRD pattern of the fabricated NPs exhibited that the TiO2 NPs contain anatase phase. Similarity in amide I and II signal intensities showed that secondary structure of the adsorbed Hb is preserved. The intrinsic fluorescence study revealed that the fluorescence quenching of Hb was done by complex formation between Hb and TiO2 NPs trough the hydrogen bond and van der Waals interactions. Synchronous fluorescence spectroscopy determined that interaction of TiO2 NPs with Hb did not unfold the Hb structure in the vicinity of the Tyr and Trp residues. Molecular docking study depicted that Glu-95, Thr-134 and Tyr-140 are involved in the formation of hydrophilic bonds. MTT data and antibacterial assays indicated that TiO2 NPs endow distinguished antibacterial activities against Gram-negative and Gram positive strains at safe concentrations. This study may reveal that fabricated TiO2 NP can be used as a safe and potent antibacterial agent.
Communicated by Ramaswamy H. Sarma 相似文献
42.
Inhibition of leptin gene expression and secretion by silibinin: possible role of estrogen receptors
43.
Niknami M Patel M Witting PK Dong Q 《The international journal of biochemistry & cell biology》2009,41(5):994-997
Cytosolic phospholipase A(2)-alpha (cPLA(2)-alpha) cleaves its preferred substrate, arachidonic acid, at the sn-2 position of membrane glycerophospholipids. Stimulation of cells with agents that mobilize intracellular calcium and/or promote the phosphorylation of cPLA(2)-alpha leads to (i) translocation of the enzyme from cytosol to endoplasmic reticulum, Golgi apparatus and perinuclear membranes-where it associates with the arachidonic acid in close proximity to downstream eicosanoid-producing enzymes; and (ii) the change in configuration induced by phosphorylation increases the phospholipid binding affinity and arachidonic acid release. As a mediator of growth factors, cytokines, chemokines, and hormones that modulate survival and growth in various cell types, cPLA(2)-alpha has attracted considerable attention as a potential therapeutic target in control of inflammation and cancer. The importance of the enzyme may have been underestimated by the relatively normal phenotype in the enzyme knockout animals. A clear phenotype has emerged when these knockout animals are used as models of various diseases. 相似文献
44.
Duringventilatory acclimatization to hypoxia (VAH), the relationship betweenventilation (E) and end-tidalPCO2 (PETCO2) changes.This study was designed to determine 1) whether these changes can be seenearly in VAH and 2) if these changesare present, whether the responses differ between isocapnic andpoikilocapnic exposures. Ten healthy volunteers were studied by usingthree 8-h exposures: 1) isocapnichypoxia (IH), end-tidal PO2(PETO2) = 55 Torr andPETCO2 held at thesubject's normal prehypoxic value;2) poikilocapnic hypoxia (PH),PETO2 = 55 Torr; and3) control (C), air breathing. TheE-PETCO2relationship was determined in hyperoxia (PETO2 = 200 Torr) beforeand after the exposures. We found a significant increase in theslopes ofE-PETCO2 relationship after both hypoxic exposures compared with control (IH vs.C, P < 0.01; PH vs. C,P < 0.001; analysis of covariance with pairwise comparisons). This increase was not significantly different between protocols IH andPH. No significant changes in theintercept were detected. We conclude that 8 h of hypoxia, whetherisocapnic or poikilocapnic, increases the sensitivity of the hyperoxicchemoreflex response to CO2. 相似文献
45.
Alexi Crosby Nick P Talbot George M Balanos Simon Donoghue Marzieh Fatemian Peter A Robbins 《Journal of applied physiology》2003,95(5):1947-1954
The aims of this study were to determine 1) whether ventilatory adaptation occurred over a 5-day exposure to a constant elevation in end-tidal PCO2 and 2) whether such an exposure altered the sensitivity of the chemoreflexes to acute hypoxia and hypercapnia. Ten healthy human subjects were studied over a period of 13 days. Their ventilation, chemoreflex sensitivities, and acid-base status were measured daily before, during, and after 5 days of elevated end-tidal PCO2 at 8 Torr above normal. There was no major adaptation of ventilation during the 5 days of hypercapnic exposure. There was an increase in ventilatory chemosensitivity to acute hypoxia (from 1.35 +/- 0.08 to 1.70 +/- 0.07 l/min/%; P < 0.01) but no change in ventilatory chemosensitivity to acute hypercapnia. There was a degree of compensatory metabolic alkalosis. The results do not support the hypothesis that the ventilatory adaptation to chronic hypercapnia would be much greater with constant elevation of alveolar PCO2 than with constant elevation of inspired PCO2, as has been used in previous studies and in which the feedback loop between ventilation and alveolar PCO2 is left intact. 相似文献
46.
Mahtab Shahriari Felordi Mehdi Alikhani Zahra Farzaneh Mahmoud Alipour Choshali Marzieh Ebrahimi Hamidreza Aboulkheyr Es Abbas Piryaei Mustapha Najimi Massoud Vosough 《Journal of cellular and molecular medicine》2023,27(17):2572-2582
Anti-cancer properties of (-)-epigallocatechin-3-gallate (EGCG) are mediated via apoptosis induction, as well as inhibition of cell proliferation and histone deacetylase. Accumulation of stabilized cellular FLICE-inhibitory protein (c-FLIP)/Ku70 complex in the cytoplasm inhibits apoptosis through interruption of extrinsic apoptosis pathway. In this study, we evaluated the anti-cancer role of EGCG in gastric cancer (GC) cells through dissociation of c-FLIP/Ku70 complex. MKN-45 cells were treated with EGCG or its antagonist MG149 for 24 h. Apoptosis was evaluated by flow cytometry and quantitative RT-PCR. Protein expression of c-FLIP and Ku70 was analysed using western blot and immunofluorescence. Dissociation of c-FLIP/Ku70 complex as well as Ku70 translocation were studied by sub-cellular fractionation and co-immunoprecipitation. EGCG induced apoptosis in MKN-45 cells with substantial up-regulation of P53 and P21, down-regulation of c-Myc and Cyclin D1 as well as cell cycle arrest in S and G2/M check points. Moreover, EGCG treatment suppressed the expression of c-FLIP and Ku70, decreased their interaction while increasing the Ku70 nuclear content. By dissociating the c-FLIP/Ku70 complex, EGCG could be an alternative component to the conventional HDAC inhibitors in order to induce apoptosis in GC cells. Thus, its combination with other cancer therapy protocols could result in a better therapeutic outcome. 相似文献
47.
Dr. Somayeh Zare Dr. Leila Emami Dr. Marzieh Behrouz Reza Abbasi Khankahdani Shirin Nickpour Mina Emami Dr. Zeinab Faghih Prof. Soghra Khabnadideh 《化学与生物多样性》2023,20(7):e202201245
A series of 6-bromoquinazoline derivatives ( 5a – j ) were synthesized. Cytotoxic effectiveness of compounds was done against two cancerous cell lines (MCF-7 and SW480) by standard MTT method. Fortunately, all of the compounds showed desirable activity in reducing the viability of the studied cancerous cell lines with IC50 value in the range of 0.53–46.6 μM. Compound 5b with a fluoro substitution at meta position of the phenyl moiety showed stronger activity than cisplatin with IC50=0.53–1.95 μM. Studies on the hit compound ( 5b ) through apoptosis assay illustrated that it could induce apoptosis in MCF-7 cell lines in dose dependent manner. Molecular docking study was done to investigate the detailed binding modes and interactions with EGFR as a plausible mechanism. The drug- likeness was predicted. To survey the reactivity of compounds, DFT calculation was performed. Taken together, 6-bromoquinazoline derivatives, especially 5b can be considered as hit compounds to rational drug designing as antiproliferative agents. 相似文献
48.
Fatemeh Khosravi Ehsan Mohseni Fard Marzieh Hosseininezhad Hadi Shoorideh 《Engineering in Life Science》2023,23(8):e2300003
The glycoside hydrolase family contains enzymes that break the glycosidic bonds of carbohydrates by hydrolysis. Inulinase is one of the most important industrial enzymes in the family of Glycoside Hydrolases 32 (GH32). In this study, to identify and classify bacterial inulinases initially, 16,002 protein sequences belonging to the GH32 family were obtained using various databases. The inulin-effective enzymes (endoinulinase and exoinulinase) were identified. Eight endoinulinases (EC 3.2.1.7) and 4318 exoinulinases (EC 3.2.1.80) were found. Then, the localization of endoinulinase and exoinulinase enzymes in the cell was predicted. Among them, two extracellular endoinulinases and 1232 extracellular exoinulinases were found. The biochemical properties of 363 enzymes of the genus Arthrobacter, Bacillus, and Streptomyces (most abundant) showed that exoinulinases have an acid isoelectric point up to the neutral range due to their amino acid length. That is, the smaller the protein (336 aa), the more acidic the pI (4.39), and the larger the protein (1207 aa), the pI is in the neutral range (8.84). Also, a negative gravitational index indicates the hydrophilicity of exoinulinases. Finally, considering the biochemical properties affecting protein stability and post-translational changes studies, one enzyme for endoinulinase and 40 enzymes with desirable characteristics were selected to identify their enzyme production sources. To screen and isolate enzyme-containing strains, now with the expansion of databases and the development of bioinformatics tools, it is possible to classify, review and analyze a lot of data related to different enzyme-producing strains. Although, in laboratory studies, a maximum of 20 to 30 strains can be examined. Therefore, when more strains are examined, finally, strains with more stable and efficient enzymes were selected and introduced for laboratory activities. The findings of this study can help researchers to select the appropriate gene source from introduced strains for cloning and expression heterologous inulinase, or to extract native inulinase from introduced strains. 相似文献
49.
Samaneh Arman Marzieh Hadavi Azadeh Rezvani-Noghani Anashid Bakhtparvar Melika Fotouhi Ali Farhang Parisa Mokaberi Reza Taheri Jamshidkhan Chamani 《Luminescence》2024,39(1):e4634
In this study, cellulose nanocrystals (CNCs) were synthesized from celery stalks to be used as the platform for quercetin delivery. Additionally, CNCs and CNCs–quercetin were characterized using the results of scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and zeta potential, while their interactions with human holo-transferrin (HTF) were also investigated. We examined their interaction under physiological conditions through the exertion of fluorescence, resonance light scattering, synchronized fluorescence spectroscopy, circular dichroism, three-dimensional fluorescence spectroscopy, and fluorescence resonance energy transfer techniques. The data from SEM and TEM exhibited the spherical shape of CNCs and CNCs–quercetin and also, a decrease was detected in the size of quercetin-loaded CNCs from 676 to 473 nm that indicated the intensified water solubility of quercetin. The success of cellulose acid hydrolysis was confirmed based on the XRD results. Apparently, the crystalline index of CNCs–quercetin was reduced by the interaction of CNCs with quercetin, which also resulted in the appearance of functional groups, as shown by FTIR. The interaction of CNCs–quercetin with HTF was also demonstrated by the induced quenching in the intensity of HTF fluorescence emission and Stern–Volmer data represent the occurrence of static quenching. Overall, the effectiveness of CNCs as quercetin vehicles suggests its potential suitability for dietary supplements and pharmaceutical products. 相似文献
50.