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301.
Metagenomic investigation of the geologically unique Hellenic Volcanic Arc reveals a distinctive ecosystem with unexpected physiology 下载免费PDF全文
Anastasis Oulas H. James Tripp Manolis Mandalakis A. David Paez‐Espino Amrita Pati Patrick Chain Paraskevi Nomikou Steven Carey Stephanos Kilias Christos Christakis Georgios Kotoulas Antonios Magoulas Natalia N. Ivanova Nikos C. Kyrpides 《Environmental microbiology》2016,18(4):1122-1136
Hydrothermal vents represent a deep, hot, aphotic biosphere where chemosynthetic primary producers, fuelled by chemicals from Earth's subsurface, form the basis of life. In this study, we examined microbial mats from two distinct volcanic sites within the Hellenic Volcanic Arc (HVA). The HVA is geologically and ecologically unique, with reported emissions of CO2‐saturated fluids at temperatures up to 220°C and a notable absence of macrofauna. Metagenomic data reveals highly complex prokaryotic communities composed of chemolithoautotrophs, some methanotrophs, and to our surprise, heterotrophs capable of anaerobic degradation of aromatic hydrocarbons. Our data suggest that aromatic hydrocarbons may indeed be a significant source of carbon in these sites, and instigate additional research into the nature and origin of these compounds in the HVA. Novel physiology was assigned to several uncultured prokaryotic lineages; most notably, a SAR406 representative is attributed with a role in anaerobic hydrocarbon degradation. This dataset, the largest to date from submarine volcanic ecosystems, constitutes a significant resource of novel genes and pathways with potential biotechnological applications. 相似文献
302.
Markus Kühbacher Jürgen Bartel Barbara Hoppe Dorothea Alber Gregor Bukalis Anja U. Bräuer† Dietrich Behne Antonios Kyriakopoulos 《Journal of neurochemistry》2009,110(1):133-142
The application of radionuclides for the localization of essential trace elements in vivo and the characterization of their binding proteins is a story of intermittently made improvements of the techniques used for their detection. In this study we present the use of neutron activation analysis and different autoradiographic imaging methods including real-time digital autoradiography to reveal new insights in the hierarchy of selenium homeostasis. Selenoproteins containing the essential trace element selenium play important roles in the CNS. Although the CNS does not show the highest selenium concentration in the case of selenium-sufficient supply in comparison with other organs, it shows a high priority for selenium uptake and retention in the case of dietary selenium deficiency. To characterize the hierarchy of selenium supply in the brain, in vivo radiotracer labeling with 75 Se in rats with different selenium status was combined with autoradiographic detection of 75 Se in brain tissue sections and 75 Se-labeled selenoproteins after protein separation by two-dimensional gel electrophoresis. This study demonstrates significant differences in the uptake of 75 Se into the brain of rats with different selenium status. A brain region-specific uptake pattern of the radiotracer 75 Se in selenium-deficient rats could be revealed and the CSF was identified as a key part of the brain selenium homeostasis. 相似文献
303.
Makris T Stavroulakis G Papadopoulos D Paizis I Krespi P Tsoukala C Hatzizacharias A Votteas V 《European cytokine network》2006,17(2):137-141
White coat hypertension (WCH) or isolated clinic hypertension is generally accepted to be a benign condition, although some reports have suggested that it may be associated with an increased cardiovascular event rate or other cardiovascular alterations. It has been previously shown that essential hypertension (EH) is associated with abnormalities in haemostatic/fibrinolytic balance and endothelial function. The aim of our study was to assess the impact of WCH on fibrinolytic balance and endothelial function by measuring plasma levels of plasminogen activator inhibitor-1 (PAI-1), tissue plasminogen activator antigen (tPA), fibrinogen, and thrombomodulin. These markers were determined in 71 patients with EH, 26 with WCH and 87 normotensive healthy control subjects. The three groups were not different with respect to age, gender, smoking habits, BMI and blood lipids. Subjects with WCH were found to have increased plasma levels of PAI-1, tPA, fibrinogen and thrombomodulin compared to controls, but less compared to hypertensive ones. Our results suggest that WCH may be associated with decreased fibrinolytic potential and endothelial dysfunction, indicating that WCH may not be a completely harmless trait. 相似文献
304.
Ziakas GN Rekka EA Gavalas AM Eleftheriou PT Kourounakis PN 《Bioorganic & medicinal chemistry》2006,14(16):5616-5624
Amine or amide derivatives bearing the 2,6-di-tert-butyl phenol moiety are synthesised. Almost all are antioxidants, reduce acute inflammation and inhibit COX-1 and lipoxygenase activity. The most potent anti-inflammatory, COX-1 inhibitor and antioxidant agent, with low toxicity, is 2,6-di-tert-butyl-4-thiomorpholin-4-ylmethyl-phenol. 相似文献
305.
Abiotic stress generates ROS that signal expression of anionic glutamate dehydrogenases to form glutamate for proline synthesis in tobacco and grapevine 总被引:1,自引:0,他引:1 下载免费PDF全文
Skopelitis DS Paranychianakis NV Paschalidis KA Pliakonis ED Delis ID Yakoumakis DI Kouvarakis A Papadakis AK Stephanou EG Roubelakis-Angelakis KA 《The Plant cell》2006,18(10):2767-2781
Glutamate dehydrogenase (GDH) may be a stress-responsive enzyme, as GDH exhibits considerable thermal stability, and de novo synthesis of the alpha-GDH subunit is induced by exogenous ammonium and senescence. NaCl treatment induces reactive oxygen species (ROS), intracellular ammonia, expression of tobacco (Nicotiana tabacum cv Xanthi) gdh-NAD;A1 encoding the alpha-subunit of GDH, increase in immunoreactive alpha-polypeptide, assembly of the anionic isoenzymes, and in vitro GDH aminating activity in tissues from hypergeous plant organs. In vivo aminating GDH activity was confirmed by gas chromatorgraphy-mass spectrometry monitoring of (15)N-Glu, (15)N-Gln, and (15)N-Pro in the presence of methionine sulfoximine and amino oxyacetic acid, inhibitors of Gln synthetase and transaminases, respectively. Along with upregulation of alpha-GDH by NaCl, isocitrate dehydrogenase genes, which provide 2-oxoglutarate, are also induced. Treatment with menadione also elicits a severalfold increase in ROS and immunoreactive alpha-polypeptide and GDH activity. This suggests that ROS participate in the signaling pathway for GDH expression and protease activation, which contribute to intracellular hyperammonia. Ammonium ions also mimic the effects of salinity in induction of gdh-NAD;A1 expression. These results, confirmed in tobacco and grape (Vitis vinifera cv Sultanina) tissues, support the hypothesis that the salinity-generated ROS signal induces alpha-GDH subunit expression, and the anionic iso-GDHs assimilate ammonia, acting as antistress enzymes in ammonia detoxification and production of Glu for Pro synthesis. 相似文献
306.
Hadjipavlou-Litina D Magoulas GE Bariamis SE Drainas D Avgoustakis K Papaioannou D 《Bioorganic & medicinal chemistry》2010,18(23):8204-8217
A series of symmetric and asymmetric spermine (SPM) conjugates with all-trans-retinoic acid (ATRA), acitretin (ACI), (E)-3-(trioxsalen-4′-yl)acrylic acid (TRAA) and l-DOPA, amides of ACI, l-DOPA and TRAA with 1-aminobutane, benzylamine, dopamine and 1,12-diaminobutane as well as hybrid conjugates of O,O′-dimethylcaffeic acid (DMCA) with TRAA or N-fumaroyl-indole-3-carboxanilide (FICA) and 2-(2-aminoethoxy)ethanol were synthesized and their antioxidant properties were studied. The reducing activity (RA)% of the compounds were evaluated using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical-scavenging assay and found to be in the range 0–92(20 min)%/96(60 min)% at 100 μM, the most powerful being the conjugates l-DOPA-SPM-l-DOPA (8, RA = 89%/96%) and l-DOPA-dopamine (13, RA = 92%/92%). Conjugate DMCA-NH(CH2CH2O)2-FICA (14) was the most powerful LOX inhibitor with IC50 33.5 μM, followed by the conjugates ACI-NHCH2Ph (10, IC50 40.5 μM), ACI-SPM-TRAA (7, IC50 41.5 μM), DMCA-NH(CH2CH2O)2-TRAA (15, IC50 65 μM), 13 (IC50 81.5 μM) and ACI-dopamine (11, IC50 87 μM). The most potent inhibitors of lipid peroxidation at 100 μM were the conjugates 15 (98%) and ACI-SPM-ACI (4, 97%) whereas all other compounds showed activities comparable or lower than trolox. The most interesting compounds, namely ATRA-SPM-ATRA (3), 4, 10, 11 and 15, as well as unconjugated compounds such as ATRA and dopamine, were studied for their anti-inflammatory activity in vivo on rat paw oedema induced by Carrageenan and found to exhibit, for doses of 0.01 mmol/mL of conjugates per Kg of rat body weight, weaker anti-inflammatory activities (3.6–40%) than indomethacin (47%) with conjugate 3 being the most potent (40%) in this series of compounds. The cytocompatibility of selected compounds was evaluated by the viability of RAMEC cells in the presence of different concentrations (0.5–50 μM) of the compounds. Conjugates 3 (IC50 2.6 μM) and 4 (IC50 4.7 μM) were more cytotoxic than the corresponding unconjugated retinoids ATRA (IC50 18.3 μM) and ACI (IC50 14.6 μM), whereas conjugate 15 (IC50 12.9 μM) was less cytotoxic than either DCSP (IC50 11.3 μM) or the tert-butyl ester of TRAA (IC50 2.9 μM). 相似文献
307.
Filippos Kottakis Christina Befani Antonios Asiminas Maria Kontou† Georgios Koliakos‡ Theodora Choli-Papadopoulou 《Helicobacter》2009,14(3):177-179
Entire Helicobacter Pylori Neutrophil Activated Protein (HPNAP) and its truncated forms NH2 -terminal region HPNAP1–57 and C-terminal region HPNAP58–144 after cloning into pET29c vector, purification and removal of LPS traces were subjected to human neutrophil activation. Our results revealed that the C-terminal region of HPNAP is indispensable for human neutrophil stimulation and their further adhesion to endothelial cells – a step necessary to H. pylori inflammation – in a ratio equal to that exhibited by the entire protein.
In addition, experiments concerning the implication of Arabino-Galactan-Proteins (AGPs) derived from Chios Mastic Gum (CMG), the natural resin of the plant Pistacia lentiscus var. Chia revealed the inhibition of neutrophil activation and therefore their adhesion to endothelial cells, in vitro .
Both, the involvement of HPNAP C-terminal region in stimulation-adhesion of neutrophils to endothelial cells as well as the inhibition of this process by AGPs have to be further investigated and may be exploited in a future anti-inflammatory therapy for H. pylori patients. 相似文献
In addition, experiments concerning the implication of Arabino-Galactan-Proteins (AGPs) derived from Chios Mastic Gum (CMG), the natural resin of the plant Pistacia lentiscus var. Chia revealed the inhibition of neutrophil activation and therefore their adhesion to endothelial cells, in vitro .
Both, the involvement of HPNAP C-terminal region in stimulation-adhesion of neutrophils to endothelial cells as well as the inhibition of this process by AGPs have to be further investigated and may be exploited in a future anti-inflammatory therapy for H. pylori patients. 相似文献
308.
Panagiota Miltiadous Antonios Stamatakis Fotini Stylianopoulou 《Cellular and molecular neurobiology》2010,30(3):347-360
Insulin-like growth factor I (IGF-I) has been shown to act as a neuroprotectant both in in vitro studies and in in vivo animal
models of ischemia, hypoxia, trauma in the brain or the spinal cord, multiple and amyotrophic lateral sclerosis, Alzheimer’s
and Parkinson’s disease. In the present study, we investigated the neuroprotective potential of IGF-I in the “kainic acid-induced
degeneration of the hippocampus” model of temporal lobe epilepsy. Increased cell death—as detected by FluoroJade B staining—and
extensive cell loss—as determined by cresyl violet staining—were observed mainly in the CA3 and CA4 areas of the ipsilateral
and contralateral hippocampus, 7 days following intrahippocampal administration of kainic acid. Kainic acid injection also
resulted in intense astrogliosis—as assessed by the number of glial fibrillary acidic protein (GFAP) immunopositive cells—in
both hemispheres, forming a clear astroglial scar ipsilaterally to the injection site. Heat-shock protein 70 (Hsp70) immunopositive
cells were also observed in the ipsilateral dentate gyrus (DG) following kainic acid injection. When IGF-I was administered
together with kainic acid, practically no signs of degeneration were detected in the contralateral hemisphere, while in the
ipsilateral, there was a smaller degree of cell loss, reduced number of FluoroJade B-stained cells, decreased reactive gliosis
and fewer Hsp70-positive cells. Our present results extend further the cases in which IGF-I is shown to exhibit neuroprotective
properties in neurodegenerative processes in the CNS. 相似文献
309.
310.
Christos Kalofoutis Iordanis Mourouzis Georgios Galanopoulos Antonios Dimopoulos Philippos Perimenis Danai Spanou Dennis V. Cokkinos Jaipaul Singh Constantinos Pantos 《Molecular and cellular biochemistry》2010,345(1-2):161-169
It has been previously shown that regulators of physiological growth such as thyroid hormone (TH) can favorably remodel the post ischaemic myocardium. Here, we further explored whether this effect can be preserved in the presence of co-morbidities such as diabetes which accelerates cardiac remodeling and increases mortality after myocardial infarction. Acute myocardial infarction (AMI) was induced by left coronary ligation in rats with type I diabetes (DM) induced by streptozotocin administration (STZ; 35 mg/kg; i.p.) while sham-operated animals served as controls (SHAM). AMI resulted in distinct changes in cardiac function and geometry; EF% was significantly decreased in DM-AMI [37.9 ± 2.0 vs. 74.5 ± 2.1 in DM-SHAM]. Systolic and diastolic chamber dimensions were increased without concomitant increase in wall thickness and thus, wall tension index [WTI, the ratio of (Left Ventricular Internal Diameter at diastole)/2*(Posterior Wall thickness)], an index of wall stress, was found to be significantly increased in DM-AMI; 2.27 ± 0.08 versus 1.70 ± 0.05. 2D-Strain echocardiographic analysis showed reduced systolic radial strain in all segments, indicating increased loss of cardiac myocytes in the infarct related area and less compensatory hypertrophy in the viable segments. This response was accompanied by a marked decrease in the expression of TRα1 and TRβ1 receptors in the diabetic myocardium without changes in circulating T3 and T4. Accordingly, the expression of TH target genes related to cardiac contractility was altered; β-MHC and PKCα were significantly increased. TH (L-T4 and L-T3) administration prevented these changes and resulted in increased EF%, normal wall stress and increased systolic radial strain in all myocardial segments. Acute myocardial infarction in diabetic rats results in TH receptor down-regulation with important physiological consequences. TH treatment prevents this response and improves cardiac hemodynamics. 相似文献