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81.
82.
Silvia Crognale István Máthé Valentina Cardone Silvia Rita Stazi Botond Ráduly 《Geomicrobiology journal》2013,30(9):801-812
In this study a combination of both molecular and biochemical methods have been used to characterize the bacterial microbiota in water and sediment of a saline lake in Transylvania. The physicochemical characterization of the water samples from different lake depths indicated a stratification of the lake that affects the distribution of resident microorganisms, confirmed also by the significant differences in terms of functional diversity of the microbial communities in different water layers. The superficial bacterial community shows a good oxidative capability, degrading a wide range of organic substrates, yet the bottom layer community exhibits a major level of specialization. The membrane fatty acid analysis of the sediment bacterial community shows the prevalent presence of Gram negative bacteria, confirmed by the culturing techniques. Among the 24 collected isolates, 16S rRNA gene sequencing analysis permitted to identify 10 different species, belonging to Bacillus, Halomonas, Idiomarina, Marinobacter, Pseudoalteromonas, Salinivibrio, Staphylococcus genera and prevalently classified as halophiles. 相似文献
83.
Melinda Erzsébet Tóth Viktor Szegedi Edina Varga Gábor Juhász János Horváth Emőke Borbély Balázs Csibrány Róbert Alföldi Nikolett Lénárt Botond Penke Miklós Sántha 《Cell stress & chaperones》2013,18(6):759-771
Hsp27 belongs to the small heat shock protein family, which are ATP-independent chaperones. The most important function of Hsp27 is based on its ability to bind non-native proteins and inhibit the aggregation of incorrectly folded proteins maintaining them in a refolding-competent state. Additionally, it has anti-apoptotic and antioxidant activities. To study the effect of Hsp27 on memory and synaptic functions, amyloid-β (Aβ) accumulation, and neurodegeneration, we generated transgenic mice overexpressing human Hsp27 protein and crossed with APPswe/PS1dE9 mouse strain, a mouse model of Alzheimer's disease (AD). Using different behavioral tests, we found that spatial learning was impaired in AD model mice and was rescued by Hsp27 overexpression. Electrophysiological recordings have revealed that excitability of neurons was significantly increased, and long-term potentiation (LTP) was impaired in AD model mice, whereas they were normalized in Hsp27 overexpressing AD model mice. Using anti-amyloid antibody, we counted significantly less amyloid plaques in the brain of APPswe/PS1dE9/Hsp27 animals compared to AD model mice. These results suggest that overexpression of Hsp27 protein might ameliorate certain symptoms of AD. 相似文献
84.
Grimm MO Kuchenbecker J Grösgen S Burg VK Hundsdörfer B Rothhaar TL Friess P de Wilde MC Broersen LM Penke B Péter M Vígh L Grimm HS Hartmann T 《The Journal of biological chemistry》2011,286(16):14028-14039
Alzheimer disease is characterized by accumulation of the β-amyloid peptide (Aβ) generated by β- and γ-secretase processing of the amyloid precursor protein (APP). The intake of the polyunsaturated fatty acid docosahexaenoic acid (DHA) has been associated with decreased amyloid deposition and a reduced risk in Alzheimer disease in several epidemiological trials; however, the exact underlying molecular mechanism remains to be elucidated. Here, we systematically investigate the effect of DHA on amyloidogenic and nonamyloidogenic APP processing and the potential cross-links to cholesterol metabolism in vivo and in vitro. DHA reduces amyloidogenic processing by decreasing β- and γ-secretase activity, whereas the expression and protein levels of BACE1 and presenilin1 remain unchanged. In addition, DHA increases protein stability of α-secretase resulting in increased nonamyloidogenic processing. Besides the known effect of DHA to decrease cholesterol de novo synthesis, we found cholesterol distribution in plasma membrane to be altered. In the presence of DHA, cholesterol shifts from raft to non-raft domains, and this is accompanied by a shift in γ-secretase activity and presenilin1 protein levels. Taken together, DHA directs amyloidogenic processing of APP toward nonamyloidogenic processing, effectively reducing Aβ release. DHA has a typical pleiotropic effect; DHA-mediated Aβ reduction is not the consequence of a single major mechanism but is the result of combined multiple effects. 相似文献
85.
Spencer NY Yan Z Boudreau RL Zhang Y Luo M Li Q Tian X Shah AM Davisson RL Davidson B Banfi B Engelhardt JF 《The Journal of biological chemistry》2011,286(11):8977-8987
Redox-regulated signal transduction is coordinated by spatially controlled production of reactive oxygen species within subcellular compartments. The nucleus has long been known to produce superoxide (O(2)(·-)); however, the mechanisms that control this function remain largely unknown. We have characterized molecular features of a nuclear superoxide-producing system in the mouse liver. Using electron paramagnetic resonance, we investigated whether several NADPH oxidases (NOX1, 2, and 4) and known activators of NOX (Rac1, Rac2, p22(phox), and p47(phox)) contribute to nuclear O(2)(·-) production in isolated hepatic nuclei. Our findings demonstrate that NOX4 most significantly contributes to hepatic nuclear O(2)(·-) production that utilizes NADPH as an electron donor. Although NOX4 protein immunolocalized to both nuclear membranes and intranuclear inclusions, fluorescent detection of NADPH-dependent nuclear O(2)(·-) predominantly localized to the perinuclear space. Interestingly, NADP(+) and G6P also induced nuclear O(2)(·-) production, suggesting that intranuclear glucose-6-phosphate dehydrogenase (G6PD) can control NOX4 activity through nuclear NADPH production. Using G6PD mutant mice and G6PD shRNA, we confirmed that reductions in nuclear G6PD enzyme decrease the ability of hepatic nuclei to generate O(2)(·-) in response to NADP(+) and G6P. NOX4 and G6PD protein were also observed in overlapping microdomains within the nucleus. These findings provide new insights on the metabolic pathways for substrate regulation of nuclear O(2)(·-) production by NOX4. 相似文献
86.
Fluorescent cell analytical techniques require the incorporation of a fluorophore into the target molecule without causing a significant change in the native conformation. Many short peptides have a limited number of reactive groups that can be labeled without affecting the biological activity. In this work we present several methods for labeling beta-amyloid peptides (betaA[25-35], betaA[1-40]) and their derivatives (LPFFD, RIIGL and RVVIA) with different chromophores exclusively at the N-terminus. In the case of liquid-phase labeling, fluorescein isothiocyanate was used. The side-chain amino function of Lys, if present in the sequence, was protected with an Fmoc group, whereby the hydrophobic character of the peptide was further increased. The labeling reaction was carried out in an appropriate deaggregating solvent, DMSO. For solid-phase labeling, 5(6)-carboxyfluorescein and 7-amino-4-methyl-3-coumarinylacetic acid were applied. Several cleavage cocktails were tested for removal of the labeled amyloid peptides from the resin in order to completely suppress the oxidation of Met. 相似文献
87.
A new, crystalline 5'-thiol modifier phosphoramidite monomer (3), suitable for DNA synthesis, has been prepared. This monomer has been built into an oligonucleotide using the standard protocol. After cleavage, purification and removal of the trityl group with Ag(+), a free 5'-thiol terminal oligonucleotide (15) has been obtained which was subsequently coupled to a cysteine derivative via a disulfide bridge to afford conjugate 16. 相似文献
88.
Haley K Igyártó BZ Ortner D Bobr A Kashem S Schenten D Kaplan DH 《Journal of immunology (Baltimore, Md. : 1950)》2012,188(9):4334-4339
Langerhans cells (LC) are a subset of skin-resident dendritic cells (DC) that reside in the epidermis as immature DC, where they acquire Ag. A key step in the life cycle of LC is their activation into mature DC in response to various stimuli, including epicutaneous sensitization with hapten and skin infection with Candida albicans. Mature LC migrate to the skin-draining LN, where they present Ag to CD4 T cells and modulate the adaptive immune response. LC migration is thought to require the direct action of IL-1β and IL-18 on LC. In addition, TLR ligands are present in C. albicans, and hapten sensitization produces endogenous TLR ligands. Both could contribute to LC activation. We generated Langerin-Cre MyD88(fl) mice in which LC are insensitive to IL-1 family members and most TLR ligands. LC migration in the steady state, after hapten sensitization and postinfection with C. albicans, was unaffected. Contact hypersensitivity in Langerin-Cre MyD88(fl) mice was similarly unaffected. Interestingly, in response to C. albicans infection, these mice displayed reduced proliferation of Ag-specific CD4 T cells and defective Th17 subset differentiation. Surface expression of costimulatory molecules was intact on LC, but expression of IL-1β, IL-6, and IL-23 was reduced. Thus, sensitivity to MyD88-dependent signals is not required for LC migration, but is required for the full activation and function of LC in the setting of fungal infection. 相似文献
89.
Role of Nox isoforms in angiotensin II-induced oxidative stress and endothelial dysfunction in brain
Chrissobolis S Banfi B Sobey CG Faraci FM 《Journal of applied physiology (Bethesda, Md. : 1985)》2012,113(2):184-191
Angiotensin II (Ang II) promotes vascular disease through several mechanisms including by producing oxidative stress and endothelial dysfunction. Although multiple potential sources of reactive oxygen species exist, the relative importance of each is unclear, particularly in individual vascular beds. In these experiments, we examined the role of NADPH oxidase (Nox1 and Nox2) in Ang II-induced endothelial dysfunction in the cerebral circulation. Treatment with Ang II (1.4 mg·kg(-1)·day(-1) for 7 days), but not vehicle, increased blood pressure in all groups. In wild-type (WT; C57Bl/6) mice, Ang II reduced dilation of the basilar artery to the endothelium-dependent agonist acetylcholine compared with vehicle but had no effect on responses in Nox2-deficient (Nox2(-/y)) mice. Ang II impaired responses to acetylcholine in Nox1 WT (Nox1(+/y)) and caused a small reduction in responses to acetylcholine in Nox1-deficient (Nox1(-/y)) mice. Ang II did not impair responses to the endothelium-independent agonists nitroprusside or papaverine in either group. In WT mice, Ang II increased basal and phorbol-dibutyrate-stimulated superoxide production in the cerebrovasculature, and these increases were abolished in Nox2(-/y) mice. Overall, these data suggest that Nox2 plays a relatively prominent role in mediating Ang II-induced oxidative stress and cerebral endothelial dysfunction, with a minor role for Nox1. 相似文献
90.