排序方式: 共有94条查询结果,搜索用时 15 毫秒
41.
De Keersmaecker K Real PJ Gatta GD Palomero T Sulis ML Tosello V Van Vlierberghe P Barnes K Castillo M Sole X Hadler M Lenz J Aplan PD Kelliher M Kee BL Pandolfi PP Kappes D Gounari F Petrie H Van der Meulen J Speleman F Paietta E Racevskis J Wiernik PH Rowe JM Soulier J Avran D Cavé H Dastugue N Raimondi S Meijerink JP Cordon-Cardo C Califano A Ferrando AA 《Nature medicine》2010,16(11):1321-1327
42.
Anastasia Z. Kalea Fotini N. Lamari Achilleas D. Theocharis Dale A. Schuschke Nikos K. Karamanos Dorothy J. Klimis-Zacas 《Biometals》2006,19(5):535-546
We examined the effect of dietary Mn on the composition and structure of heparan sulfate (HS) glycosaminoglycans (GAGs) of
rat aorta. Animals were randomly assigned to either a Mn deficient (MnD), adequate (MnA) or supplemented (MnS) diet (Mn<1,
10–15 and 45–50 ppm, respectively). After 15 weeks, aortic tissue GAGs were isolated with papain digestion, alkaline borohydride
treatment and anion-exchange chromatography. Cellulose acetate electrophoresis and treatment of the fractions with specific
lyases revealed the presence of three GAG populations, i.e. hyaluronan (HA), heparan sulfate (HS) and galactosaminoglycans
(GalAGs). Disaccharide composition of the HS fractions was determined by HPCE following treatment with heparin lyases I, II
and III. In MnS aortas we observed increased concentration of total GalAGs and decreased concentration of HS and HA, when
compared to MnA aortas. Aortas from MnD and MnA rats appeared to have similar distribution of individual GAGs. Heparan sulfate
chains of MnS aortas contained higher (41%) concentration of non-sulfated units compared to MnA ones. Variable amounts of
trisulfated and disulfated units were found only in MnD and MnA groups but not in MnS. Our results demonstrate that HS biosynthesis
in the rat aorta undergoes marked structural modifications that depend upon dietary Mn intake. The reduced expression and
undersulfation of HSPGs with Mn supplementation might indicate a reduced ability of vascular cells to interact with biologically
active molecules such as growth factors. Alterations in cell-membrane binding ability to a variety of extracellular ligands
might affect signal-transduction pathways and arterial functional properties. 相似文献
43.
Malisiova F Hatziantoniou S Dimas K Kletstas D Demetzos C 《Zeitschrift für Naturforschung. C, Journal of biosciences》2004,59(5-6):330-334
The seeds of the almond tree [(Prunus dulcis (Mill.) D. A. Webb. (syn. Prunus amygdalus)] were collected in two different periods of maturity and were studied for their lipid content. The total lipids (TL) were extracted by the Bligh-Dyer method and the lipid classes have been isolated by chromatographic techniques and were analyzed by HPTLC coupled with a flame ionization detector (HPTLC/FID) and GC-MS. The oils were found to be rich in neutral lipids (89.9% and 96.3% of total lipids) and low in polar lipids (10.1% and 3.7% of total lipids) for the immature and mature seed oils, respectively. The neutral lipid fraction consisted mainly of triacylglycerides whereas the polar lipids mainly consisted of phospholipids. GC-MS data showed that the main fatty acid for both oils was 9-octadecenoic acid (oleic acid). The unsaturated fatty acids were found as high as 89.4% and 89.7%, while the percentage of the saturated fatty acids was found 10.6% and 10.3% for the immature and mature seed oils, respectively. Liposomes were prepared from the isolated phospholipids using the thin lipid film methodology, and their physical properties were characterized. Cytotoxicity was found absent when assayed against normal and cancerous cell lines. These new formulations may have future applications for encapsulation and delivery of drugs and cosmetically active ingredients. 相似文献
44.
Fotini A. Koutroumpa Daniel Rougon Coralie Bertheau François Lieutier Géraldine Roux‐Morabito 《Biological journal of the Linnean Society. Linnean Society of London》2013,109(2):354-376
Phylogenetic relationships within the European Monochamus (Coleoptera: Cerambycidae) remain understudied despite their increasing importance in the Pine Wood Nematode spread in Europe. To clarify the delimitation and the evolutionary history of the two main European Monochamus species, Monochamus galloprovincialis and Monochamus sutor, as well as their sub‐species, a comparative study using morphological, molecular, and biogeographical criterions was conducted. Four morphological characters, including a newly‐described morphological character on the male genitalia, separated the two species. Additionally, molecular data revealed twelve and two single nucleotide polymorphisms in cytochrome oxidase c subunit I and 28S, respectively, supporting species segregation. By contrast, incongruence between morphological and genetic results did not allow discriminating the sub‐species of M. galloprovincialis and M. sutor, even though mitochondrial DNA revealed intraspecific differentiation, mostly consenting to a multiple refugia origin. Within‐species variability was explained to a large extent by biogeography (i.e. altitude, climate). These different ecological adaptations within beetle species, together with potential climate change impact, increase the risk of spreading the nematode across Europe to novel conifer hosts and challenge the European biosecurity. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109 , 354–376. 相似文献
45.
Kristo AS Malavaki CJ Lamari FN Karamanos NK Klimis-Zacas D 《The Journal of nutritional biochemistry》2012,23(8):961-965
Glycosaminoglycans (GAGs) are essential polysaccharide components of extracellular matrix and cell surface with key roles on numerous vascular wall functions. Previous studies have documented a role of wild blueberries on the GAG profile of the Sprague-Dawley rat with a functional endothelium as well as in the vascular tone of the spontaneously hypertensive rat (SHR) with endothelial dysfunction. In the present study, the effect of wild blueberries on the composition and structure of aortic GAGs was examined in 20-week-old SHRs after 8 weeks on a control (C) or a wild blueberry-enriched diet (WB). Aortic tissue GAGs were isolated following pronase digestion and anion-exchange chromatography. Treatment of the isolated populations with specific GAG-degrading lyases and subsequent electrophoretic profiling revealed the presence of three GAG species, i.e., hyaluronic acid (HA), heparan sulfate (HS) and galactosaminoglycans (GalAGs). A notable reduction of the total sulfated GAGs and a redistribution of the aortic GAG pattern were recorded in the WB as compared to the C group: a 25% and 10% increase in HA and HS, respectively, and an 11% decrease in GalAGs. Fine biochemical analysis of GalAGs at the level of constituent disaccharides with high-performance capillary electrophoresis revealed a notable increase of nonsulfated (18.0% vs. 10.7%) and a decrease of disulfated disaccharides (2.2% vs. 5.3%) in the WB aorta. This is the first study to report the redistribution of GAGs at the level of composition and their fine structural characteristics with implications for the endothelial dysfunction of the SHR. 相似文献
46.
Fragkouli A Papatheodoropoulos C Georgopoulos S Stamatakis A Stylianopoulou F Tsilibary EC Tzinia AK 《Journal of neurochemistry》2012,121(2):239-251
Evidence accumulating during the past few years points to a significant role of matrix metalloproteinase 9 (MMP9) enzymatic activity in synaptic plasticity and cognitive processes. We have previously demonstrated that MMP9 is involved in receptor-mediated α-secretase-like cleavage of APP in vitro, resulting in increased secretion of sAPPα, the soluble N-terminal product of the non-amyloidogenic pathway known to be involved in neuronal plasticity and memory formation. To study the in vivo role of MMP9, we have generated transgenic mice over-expressing MMP9 in the brain. Herein, we demonstrate that MMP9 transgenic animals display enhanced performance in the non-spatial novel object recognition and the spatial water-maze task and that their enhanced performance was accompanied by increased dendritic spine density in the hippocampus and cortex following behavioural testing. Consistent with the above observations, the electrophysiological analysis revealed prolonged maintenance of long-term synaptic potentiation in hippocampal slices from MMP9 transgenic mice. Moreover, elevated sAPPα levels in the hippocampus and cortex of MPP9 transgenic animals were also observed. Overall, our results extend previous findings on the physiological role of MMP9 in neuronal plasticity and furthermore reveal that, APP may be one of the physiological proteolytic targets of MMP9 in vivo. 相似文献
47.
Ghost mtDNA haplotypes generated by fortuitous NUMTs can deeply disturb infra‐specific genetic diversity and phylogeographic pattern 下载免费PDF全文
Julien Haran Fotini Koutroumpa Emmanuelle Magnoux Alain Roques Géraldine Roux 《Journal of Zoological Systematics and Evolutionary Research》2015,53(2):109-115
Nuclear copies of mitochondrial DNA (NUMTs or mitochondrial pseudogenes) are known to impede the detection of interspecific genetic diversity. But the effect of these artifacts on phylogeographic reconstruction remains under evaluated. In this study, we analysed a set of 115 sequences of a fragment of the cytochrome c oxidase subunit I gene (COI) of Monochamus galloprovincialis (Coleoptera, Cerambycidae) for which overlapping signals in sequencing electropherograms were observed. Comparison of full and corrected ‘ambiguities‐free’ data sets reveals the prevalence of numerous supernumerary haplotypes that deeply affect genetic diversity indices and phylogeographic patterns of this species. Slightly divergent pseudogenes were recovered in 49 of the 115 sequences. These results highlight the potential misdetection of NUMTs using current control methods and the consequences on phylogeographic structure. To test the frequency of unintended amplification of NUMTs, a cloning was performed on 15 individuals. An average of 3.72 and a maximum of six paralogous sequences with different levels of divergence were identified among individual cloned. Within individual pairwise distance between paralogs raised 1.4%. This work calls for awareness to the presence of undetected NUMTs within mitochondrial data sets, especially at infra‐specific level. 相似文献
48.
49.
Malavaki CJ Asimakopoulou AP Lamari FN Theocharis AD Tzanakakis GN Karamanos NK 《Analytical biochemistry》2008,374(1):213-220
Exogenous administration of chondroitin sulfate (CS) is widely practiced for the treatment of osteoarthritis, although the efficacy of this treatment has not been completely established by clinical studies. A reason for the inconsistency of the results may be the quality of the CS preparations, which are commercially available as dietary supplements. In this article, we describe the development of a new method of capillary electrophoresis (CE) for the quantification of CS concentrations, screening for other glycosaminoglycan or DNA impurities and determination of hyaluronan impurities in CS raw materials, tablets, hard capsules, and liquid formulations. Analysis is performed within 12 min in bare fused silica capillaries using reversed polarity and an operating phosphate buffer of low pH. The method has high sensitivity (lower limit of quantitation [LLOQ] values of 30.0 microg/ml for CS and 5.0 microg/ml for hyaluronan), high precision, and accuracy. Analysis of 11 commercially available products showed the presence of hyaluronan impurities in most of them (up to 1.5%). CE analysis of the samples after treatment with chondroitinase ABC and ACII, which depolymerize the chains to unsaturated disaccharides, with a previously described method (Karamanos et al., J. Chromatogr. A 696 (1995) 295-305) confirmed the results of hyaluronan determination and showed that the structural characteristics (i.e., disaccharide composition) of CS are very different, showing the different species or tissue origin and possibly affecting the therapeutic outcome. 相似文献
50.
Meta-analysis offers the opportunity to combine evidence from retrospectively accumulated or prospectively generated data.
Meta-analyses may provide summary estimates and can help in detecting and addressing potential inconsistency between the combined
datasets. Application of meta-analysis in genetic associations presents considerable potential and several pitfalls. In this
review, we present basic principles of meta-analytic methods, adapted for human genome epidemiology. We describe issues that
arise in the retrospective or the prospective collection of relevant data through various sources, common traps to consider
in the appraisal of evidence and potential biases that may interfere. We describe the relative merits and caveats for common
methods used to trace inconsistency across studies along with possible reasons for non-replication of proposed associations.
Different statistical models may be employed to combine data and some common misconceptions may arise in the process. Several
meta-analysis diagnostics are often applied or misapplied in the literature, and we comment on their use and limitations.
An alternative to overcome limitations arising from retrospective combination of data from published studies is to create
networks of research teams working in the same field and perform collaborative meta-analyses of individual participant data,
ideally on a prospective basis. We discuss the advantages and the challenges inherent in such collaborative approaches. Meta-analysis
can be a useful tool in dissecting the genetics of complex diseases and traits, provided its methods are properly applied
and interpreted. 相似文献