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101.
102.
Li W Ghosh M Eftekhari S Yuan XM 《Biochemical and biophysical research communications》2011,(4):711-716
Endothelial dysfunction and cell death play an important role in pathogenesis of atherosclerosis. 7-Oxysterols, the major cytotoxic component found in oxidized low-density lipoprotein, are toxic to endothelial cells. However, the pathways and molecular mechanism involved in the process remain incompletely understood. In this study, we first investigate whether 7β-hydroxycholesterol (7βOH) or 7-ketocholesterol (7keto) induces apoptosis of human endothelial cell line (HUVEC-CS). We then examine possible involved pathways by focusing on cellular lipid, lysosomal pathways, cellular oxidative stress and mitochondrial pathways. Our results for the first time showed that 7-oxysterols induced apoptotic cell death of HUVEC-CS after 24 h, which was preceded by early lipid accumulation (6 h) and lysosomal membrane permeabilization (6−12 h). Afterward, levels of reactive oxygen species, mitochondrial membrane permeabilization, and lysosomal cathepsin were increased assayed by immuno-cytochemistry and blotting. Notably, the exposure to 7βOH or 7keto induced expressions and secretion of isoforms of von Willebrand factor (VWF). We conclude that apoptosis of HUVEC-CS induced by 7βOH or 7keto mediates by early lysosomal lipid accumulation and oxidative lysosomal pathways, which results in induction and release of VWF. The results suggest the cell death induced by 7-oxysterols may contribute to endothelial dysfunction and atherothrombosis. 相似文献
103.
Structural characterisation of a uracil containing hairpin DNA by NMR and molecular dynamics. 下载免费PDF全文
Three-dimensional (3D) structure of a hairpin DNA d-CTAGAGGATCCTTTUGGATCCT (22mer; abbreviated as U4-hairpin), which has a uracil nucleotide unit at the fourth position from the 5' end of the tetra-loop has been solved by NMR spectroscopy. The(1)H resonances of this hairpin have been assigned almost completely. NMR restrained molecular dynamics and energy minimisation procedures have been used to describe the 3D structure of the U4 hairpin. This study establishes that the stem of the hairpin adopts a right handed B-DNA conformation while the T(12)and U(15)nucleotide stack upon 3' and 5' ends of the stem, respectively. Further, T(14)stacks upon both T(12)and U(15)while T(13)partially stacks upon T(14). Very weak stacking interaction is observed between T(13)and T(12). All the individual nucleotide bases adopt ' anti ' conformation with respect to their sugar moiety. The turning phosphate in the loop is located between T(13)and T(14). The stereochemistry of U(15)mimics the situation where uracil would stack in a B-DNA conformation. This could be the reason as to why the U4-hairpin is found to be the best substrate for its interaction with uracil DNA glycosylase (UDG) compared to the other substrates in which the uracil is at the first, second and third positions of the tetra-loop from its 5' end, as reported previously. 相似文献
104.
Ponnada Suresh Kumar KK Pulicherla Mrinmoy Ghosh Anmol Kumar KRS Sambasiva Rao 《Bioinformation》2011,6(8):311-314
Enzymes from psychrophiles catalyze the reactions at low temperatures with higher specific activity. Among all the psychrophilic enzymes produced, cold active
β-galactosidase from marine psychrophiles revalorizes a new arena in numerous areas at industrial level. The hydrolysis of lactose in to glucose and galactose by
cold active β-galactosidase offers a new promising approach in removal of lactose from milk to overcome the problem of lactose intolerance. Herein we propose, a
3D structure of cold active β-galactosidase enzyme sourced from Pseudoalteromonas haloplanktis by using Modeler 9v8 and best model was developed having
88% of favourable region in ramachandran plot. Modelling was followed by docking studies with the help of Auto dock 4.0 against the three substrates lactose,
ONPG and PNPG. In addition, comparative docking studies were also performed for the 3D model of psychrophilic β-galactosidase with mesophilic and
thermophilic enzymes. Docking studies revealed that binding affinity of enzyme towards the three different substrates is more for psychrophilic enzyme when
compared with mesophilic and thermophilic enzymes. It indicates that the enzyme has high specific activity at low temperature when compared with mesophilic
and thermophilic enzymes. 相似文献
105.
Kamala Mitra Abhisek Brata Ghosh Arpita Sarkar Namrata Saha Amit Kumar Dutta 《Biochemical and biophysical research communications》2014
This article reports simple, green and efficient synthesis of γ-Fe2O3 nanoparticles (NPs) (maghemite) through single-source precursor approach for colorimetric estimation of human glucose level. The γ-Fe2O3 NPs, having cubic morphology with an average particle size of 30 nm, exhibited effective peroxidase-like activity through the catalytic oxidation of peroxidase substrate 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H2O2 producing a blue-colored solution. On the basis of this colored-reaction, we have developed a simple, cheap, highly sensitive and selective colorimetric method for estimation of glucose using γ-Fe2O3/TMB/glucose–glucose oxidase (GOx) system in the linear range from 1 to 80 μM with detection limit of 0.21 μM. The proposed glucose sensor displays faster response, good stability, reproducibility and anti-interference ability. Based on this simple reaction process, human blood and urine glucose level can be monitored conveniently. 相似文献
106.
Alice Ward Racca Michael J. Rynkiewicz Nicholas LaFave Anita Ghosh William Lehman Jeffrey R. Moore 《The Journal of biological chemistry》2020,295(50):17128
Dilated cardiomyopathy (DCM) is associated with mutations in cardiomyocyte sarcomeric proteins, including α-tropomyosin. In conjunction with troponin, tropomyosin shifts to regulate actomyosin interactions. Tropomyosin molecules overlap via tropomyosin–tropomyosin head-to-tail associations, forming a continuous strand along the thin filament. These associations are critical for propagation of tropomyosin''s reconfiguration along the thin filament and key for the cooperative switching between heart muscle contraction and relaxation. Here, we tested perturbations in tropomyosin structure, biochemistry, and function caused by the DCM-linked mutation, M8R, which is located at the overlap junction. Localized and nonlocalized structural effects of the mutation were found in tropomyosin that ultimately perturb its thin filament regulatory function. Comparison of mutant and WT α-tropomyosin was carried out using in vitro motility assays, CD, actin co-sedimentation, and molecular dynamics simulations. Regulated thin filament velocity measurements showed that the presence of M8R tropomyosin decreased calcium sensitivity and thin filament cooperativity. The co-sedimentation of actin and tropomyosin showed weakening of actin-mutant tropomyosin binding. The binding of troponin T''s N terminus to the actin-mutant tropomyosin complex was also weakened. CD and molecular dynamics indicate that the M8R mutation disrupts the four-helix bundle at the head-to-tail junction, leading to weaker tropomyosin–tropomyosin binding and weaker tropomyosin–actin binding. Molecular dynamics revealed that altered end-to-end bond formation has effects extending toward the central region of the tropomyosin molecule, which alter the azimuthal position of tropomyosin, likely disrupting the mutant thin filament response to calcium. These results demonstrate that mutation-induced alterations in tropomyosin–thin filament interactions underlie the altered regulatory phenotype and ultimately the pathogenesis of DCM. 相似文献
107.
108.
Sudipta Hazra Subhalakshmi Ghosh Madhushree Das Sarma Smriti Sharma Mousumi Das Prakash Saudagar Vijay Kumar Prajapati Vikash Kumar Dubey Shyam Sundar Banasri Hazra 《Experimental parasitology》2013
World health organization has called for academic research and development of new chemotherapeutic strategies to overcome the emerging resistance and side effects exhibited by the drugs currently used against leishmaniasis. Diospyrin, a bis-naphthoquinone isolated from Diospyros montana Roxb., and its semi-synthetic derivatives, were reported for inhibitory activity against protozoan parasites including Leishmania. Presently, we have investigated the antileishmanial effect of a di-epoxide derivative of diospyrin (D17), both in vitro and in vivo. Further, the safety profile of D17 was established by testing its toxicity against normal macrophage cells (IC50 ∼ 20.7 μM), and also against normal BALB/c mice in vivo. The compound showed enhanced activity (IC50 ∼ 7.2 μM) as compared to diospyrin (IC50 ∼ 12.6 μM) against Leishmania donovani promastigotes. Again, D17 was tested on L. donovani BHU1216 isolated from a sodium stibogluconate-unresponsive patient, and exhibited selective inhibition of the intracellular amastigotes (IC50 ∼ 0.18 μM). Also, treatment of infected BALB/c mice with D17 at 2 mg/kg/day reduced the hepatic parasite load by about 38%. Subsequently, computational docking studies were undertaken on selected enzymes of trypanothione metabolism, viz. trypanothione reductase (TryR) and ornithine decarboxylase (ODC), followed by the enzyme kinetics, where D17 demonstrated non-competitive inhibition of the L. donovani ODC, but could not inhibit TryR. 相似文献
109.
Diptiman Choudhury Arnab GanguliDebabrata Ghosh Dastidar Bipul R. AcharyaAmlan Das Gopal Chakrabarti 《Biochimie》2013
Apigenin, a natural flavone, present in many plants sources, induced apoptosis and cell death in lung epithelium cancer (A549) cells with an IC50 value of 93.7 ± 3.7 μM for 48 h treatment. Target identification investigations using A549 cells and also in cell-free system demonstrated that apigenin depolymerized microtubules and inhibited reassembly of cold depolymerized microtubules of A549 cells. Again apigenin inhibited polymerization of purified tubulin with an IC50 value of 79.8 ± 2.4 μM. It bounds to tubulin in cell-free system and quenched the intrinsic fluorescence of tubulin in a concentration- and time-dependent manner. The interaction was temperature-dependent and kinetics of binding was biphasic in nature with binding rate constants of 11.5 × 10−7 M−1 s−1 and 4.0 × 10−9 M−1 s−1 for fast and slow phases at 37 °C, respectively. The stoichiometry of tubulin–apigenin binding was 1:1 and binding the binding constant (Kd) was 6.08 ± 0.096 μM. Interestingly, apigenin showed synergistic anti-cancer effect with another natural anti-tubulin agent curcumin. Apigenin and curcumin synergistically induced cell death and apoptosis and also blocked cell cycle progression at G2/M phase of A549 cells. The synergistic activity of apigenin and curcumin was also apparent from their strong depolymerizing effects on interphase microtubules and inhibitory effect of reassembly of cold depolymerized microtubules when used in combinations, indicating that these ligands bind to tubulin at different sites. In silico modeling suggested apigenin bounds at the interphase of α–β-subunit of tubulin. The binding site is 19 Å in distance from the previously predicted curcumin binding site. Binding studies with purified protein also showed both apigenin and curcumin can simultaneously bind to purified tubulin. Understanding the mechanism of synergistic effect of apigenin and curcumin could be helped to develop anti-cancer combination drugs from cheap and readily available nutraceuticals. 相似文献
110.
The low engraftment and retention rate of mesenchymal stem cells (MSCs) at the target site indicates that the potential benefits of MSC-based therapies can be attributed to their paracrine signaling. In this study, the extracellular matrices (ECMs) deposited by bone marrow-derived human MSCs in the presence and absence of ascorbic acid was characterized. MSCs were seeded on top of decellularized ECM (dECM) and the concentrations of proangiogenic and antiangiogenic molecules released in culture (conditioned) media was compared. Effects of ECM derived from MSCs with different passage numbers on MSC secretome was also investigated. Our study revealed that the expression of proangiogenesis-related factors were upregulated when MSCs were harvested on dECMs, irrespective of media supplementation, as compared with those cultured on tissue culture plates. In addition, dECM generated in the presence of ascorbic acid promoted the expression of proangiogenic molecules as compared with dECM-derived in absence of media supplementation. Further, it was observed that the effectiveness of dECM to stimulate proangiogenic signaling of MSCs was reduced as cell passage number was increased from P3 to P5. The proliferation as well as capillary morphogenesis of human umbilical vein endothelial cells (HUVECs) in the presence of conditioned media were enhanced compared with the normal HUVECs culture media. These data indicate that the secretory signatures of MSCs and consequently, the therapeutic efficacy of MSCs can be regulated by presentation of dECM composition and variation of its composition. 相似文献