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11.
This review deals with the effects of synthetic and natural fatty acids on the biophysical properties of membranes, and on their implication on cell function. Natural fatty acids are constituents of more complex lipids, like triacylglycerides or phospholipids, which are used by cells to store and obtain energy, as well as for structural purposes. Accordingly, natural and synthetic fatty acids may modify the structure of the lipid membrane, altering its microdomain organization and other physical properties, and provoking changes in cell signaling. Therefore, by modulating fatty acids it is possible to regulate the structure of the membrane, influencing the cell processes that are reliant on this structure and potentially reverting pathological cell dysfunctions that may provoke cancer, diabetes, hypertension, Alzheimer's and Parkinson's disease. The so-called Membrane Lipid Therapy offers a strategy to regulate the membrane composition through drug administration, potentially reverting pathological processes by re-adapting cell membrane structure. Certain fatty acids and their synthetic derivatives are described here that may potentially be used in such therapies, where the cell membrane itself can be considered as a target to combat disease. This article is part of a Special Issue entitled: Membrane Structure and Function: Relevance in the Cell's Physiology, Pathology and Therapy. 相似文献
12.
Interactive effects between plant functional types and soil factors on tundra species diversity and community composition
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Maitane Iturrate‐Garcia Michael J. O'Brien Olga Khitun Samuel Abiven Pascal A. Niklaus Gabriela Schaepman‐Strub 《Ecology and evolution》2016,6(22):8126-8137
Plant communities are coupled with abiotic factors, as species diversity and community composition both respond to and influence climate and soil characteristics. Interactions between vegetation and abiotic factors depend on plant functional types (PFT) as different growth forms will have differential responses to and effects on site characteristics. However, despite the importance of different PFT for community assembly and ecosystem functioning, research has mainly focused on vascular plants. Here, we established a set of observational plots in two contrasting habitats in northeastern Siberia in order to assess the relationship between species diversity and community composition with soil variables, as well as the relationship between vegetation cover and species diversity for two PFT (nonvascular and vascular). We found that nonvascular species diversity decreased with soil acidity and moisture and, to a lesser extent, with soil temperature and active layer thickness. In contrast, no such correlation was found for vascular species diversity. Differences in community composition were found mainly along soil acidity and moisture gradients. However, the proportion of variation in composition explained by the measured soil variables was much lower for nonvascular than for vascular species when considering the PFT separately. We also found different relationships between vegetation cover and species diversity according the PFT and habitat. In support of niche differentiation theory, species diversity and community composition were related to edaphic factors. The distinct relationships found for nonvascular and vascular species suggest the importance of considering multiple PFT when assessing species diversity and composition and their interaction with edaphic factors. Synthesis: Identifying vegetation responses to edaphic factors is a first step toward a better understanding of vegetation–soil feedbacks under climate change. Our results suggest that incorporating differential responses of PFT is important for predicting vegetation shifts, primary productivity, and in turn, ecosystem functioning in a changing climate. 相似文献
13.
Cholesterol incorporation into lipid bilayers, in the form of multilamellar vesicles or extruded large unilamellar vesicles, has been quantitated. To this aim, the cholesterol contents of bilayers prepared from phospholipid:cholesterol mixtures 33-75 mol% cholesterol have been measured and compared with the original mixture before lipid hydration. There is a great diversity of cases, but under most conditions the actual cholesterol proportion present in the extruded bilayers is much lower than predicted. A quantitative analysis of the vesicles is thus required before any experimental study is undertaken. 相似文献
14.
Mercedes Télez Eduardo Ortiz-Lastra Adolfo J. Gonzalez Piedad Flores Iratxe Huerta Juan M. Ramírez Maitane Barasoain Begoña Criado Isabel Arrieta 《Mutation Research - Genetic Toxicology and Environmental Mutagenesis》2010,695(1-2):46-54
The antihypertensive drug atenolol was found to induce chromosome loss, detected as micronuclei in the peripheral lymphocytes of treated patients. The fundamental question which chromosomes the micronuclei were derived from remains to be answered. Analysis of structural chromosomal aberrations (CAs) and expression of fragile sites (FS) were pursued in this study. They revealed a significantly higher incidence of chromosomal aberrations (chromatid and chromosome breaks) in patients compared with controls, where 10 FS emerged as specific. Also, the band 17q12–21, where known fragile sites have not been reported, was only expressed in atenolol-treated patients. Fluorescence in situ hybridization using chromosome-specific probes revealed the preferential involvement of chromosomes 7, 11, 17 and X in the micronuclei (MN) of patients. The results also suggest a correlation between chromosomal fragility and content of MN, and support the findings for a linkage between hypertension and a locus on chromosome 17. 相似文献
15.
Ibarguren M López DJ Montes LR Sot J Vasil AI Vasil ML Goñi FM Alonso A 《Journal of lipid research》2011,52(4):635-645
The binding and early stages of activity of a phospholipase C/sphingomyelinase from Pseudomonas aeruginosa on giant unilamellar vesicles (GUV) have been monitored using fluorescence confocal microscopy. Both the lipids and the enzyme were labeled with specific fluorescent markers. GUV consisted of a mixture of phosphatidylcholine, sphingomyelin, phosphatidylethanolamine, and cholesterol in equimolar ratios, to which 5-10 mol% of the enzyme end-product ceramide and/or diacylglycerol were occasionally added. Morphological examination of the GUV in the presence of enzyme reveals that, although the enzyme diffuses rapidly throughout the observation chamber, detectable enzyme binding appears to be a slow, random process, with new bound-enzyme-containing vesicles appearing for several minutes. Enzyme binding to the vesicles appears to be a cooperative process. After the initial cluster of bound enzyme is detected, further binding and catalytic activity follow rapidly. After the activity has started, the enzyme is not released by repeated washing, suggesting a "scooting" mechanism for the hydrolytic activity. The enzyme preferentially binds the more disordered domains, and, in most cases, the catalytic activity causes the disordering of the other domains. Simultaneously, peanut- or figure-eight-shaped vesicles containing two separate lipid domains become spherical. At a further stage of lipid hydrolysis, lipid aggregates are formed and vesicles disintegrate. 相似文献
16.
Mendizábal Y Llorens S Nava E 《American journal of physiology. Heart and circulatory physiology》2011,301(4):H1319-H1330
The obese spontaneously hypertensive rat (SHROB) is a model of metabolic syndrome in which, to our knowledge, vascular function has never been studied. The actions of insulin sensitizers (glitazones) on vascular function have not been analyzed either. Our purpose was to characterize microvascular and macrovascular responses of the SHROB and to study the effects of glitazones on these responses. The reactivity of mesenteric resistance arteries (MRAs) and the aorta from SHROBs and control rats to cumulative concentrations of phenylephrine, ACh, and sodium nitroprusside (SNP) was myographically analyzed. Some animals were orally treated with rosiglitazone (3 mg·kg(-1)·day(-1), 3 wk), and myography was performed. Phenylephrine, ACh, and SNP dose-response curves were impaired to different extents in arteries of SHROBs. Incubation with N-nitro-L-arginine methyl ester caused little effects on phenylephrine and ACh curves in MRAs but enhanced phenylephrine contractions and abolished ACh-induced relaxations of aortae. Incubation with indomethacin reduced phenylephrine reactivity and improved ACh-induced relaxations of all vessels studied. NS-398 and tempol increased relaxations to ACh of MRAs. Incubation with pioglitazone or rosiglitazone (both 10(-5) M) or oral treatment with rosiglitazone improved, to different extents, ACh and SNP curves in all vessels. Glitazone incubation diminished aortic ACh sensitivity. The release of thromboxane A(2) and PGI(2) metabolites (thromboxane B(2) and 6-keto-PGF(1α)) was analyzed. ACh increased the MRA release of thromboxane B(2) from SHROBs but not control rats, and the former was prevented by rosiglitazone coincubation. In contrast, in aortae, ACh failed to alter the release of metabolites, and rosiglitazone treatment increased that of 6-keto-PGF(1α). Thus, SHROBs displayed microvascular and macrovascular dysfunction. MRAs, but not aortae, of SHROBs revealed an impaired endothelial nitric oxide pathway, whereas both, but especially MRAs, displayed an impaired cyclooxygenase pathway. Glitazones elicited beneficial effects on macrovascular and, especially, microvascular function of SHROBs. 相似文献
17.
Aurrekoetxea M Lopez J García P Ibarretxe G Unda F 《Biology of the cell / under the auspices of the European Cell Biology Organization》2012,104(10):603-617
BACKGROUND INFORMATION: Previous studies have indicated that over-activation of the wingless interaction site (Wnt)/β-catenin signalling pathway has important implications for tooth development, at the level of cell differentiation and morphology, as well as for the production of supernumerary teeth. Here, we provide evidence for a crucial role of this signalling pathway during the stage of tooth morphogenesis. We have developed an in vitro model consisting of 14.5-day-old mouse embryo first molars, in which the Wnt pathway is overactivated by the glycogen synthase kinase-3 inhibitor 6-bromoindirubin-3'-oxime (BIO; 20 μM). RESULTS: We found that over-activation of the Wnt/β-catenin pathway delayed the differentiation and growth of the inner dental epithelium. In addition, in contrast to controls in which Nestin protein expression was restricted to differentiated odontoblasts, in BIO-treated molars, Nestin expression spread through sub-odontoblastic cellular layers. This alteration appears to be related to: (i) the over-expression of Bmp4 in the same region, (ii) the delay in odontoblast precursor cell differentiation and (iii) increased proliferation of mesenchymal cells. Furthermore, treatments longer than 6 days induced the malformation of typical dental structures and led to a total lack of cell differentiation. Finally, over-activation of the Wnt route during odontogenesis resulted in adult teeth which presented altered size, morphology and mineralisation. CONCLUSIONS: Our results indicate that Wnt/β-catenin over-activation during tooth morphogenesis is sufficient to cause dramatic alterations in the adult tooth, by delaying cellular differentiation and stimulating proliferation of the dental mesenchyme of developing teeth. 相似文献
18.
Rodriguez DA Kalko S Puig-Vilanova E Perez-Olabarría M Falciani F Gea J Cascante M Barreiro E Roca J 《Free radical biology & medicine》2012,52(1):88-94
Beneficial effects of exercise training in patients with chronic obstructive pulmonary disease (COPD) are acknowledged. However, high-intensity exercise may enhance muscle oxidative stress in severe COPD patients. We hypothesized that high-intensity exercise training of long duration does not deteriorate muscle redox status. In the vastus lateralis and blood of 18 severe COPD patients and 12 controls, before and after an 8-week training program, protein oxidation and nitration, antioxidant systems, and inflammatory cytokines were examined. At baseline, COPD patients showed greater muscle oxidative stress and superoxide dismutase activity and circulating inflammatory cytokines than controls. Among COPD patients, muscle and blood protein carbonylation levels were correlated. Both groups showed training-induced increase in VO(2) peak and decreased blood lactate levels. After training, among the COPD patients, blood protein nitration levels were significantly reduced and muscle protein oxidation and nitration levels did not cause impairment. Muscle and blood levels of inflammatory cytokines were not modified by training in either patients or controls. We conclude that in severe COPD patients, high-intensity exercise training of long duration improves exercise capacity while preventing the enhancement of systemic and muscle oxidative stress. In addition, in these patients, resting protein oxidation levels correlate between skeletal muscle and blood compartments. 相似文献
19.
Gerald Grellet-Tinner Xabier Murelaga Juan C. Larrasoa?a Luis F. Silveira Maitane Olivares Luis A. Ortega Patrick W. Trimby Ana Pascual 《PloS one》2012,7(10)