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51.
Jean-Daniel Bontemps Jean-Christophe Herv�� Jean-Michel Leban Jean-Fran?ois Dh?te 《Trees - Structure and Function》2011,25(2):237-251
Environmental drivers of forest productivity increases have been much debated. Evidence for the suggested role of increasing
nitrogen supply is lacking over long-term time scales. Tracking the footprint of environmental factors by using long-term
growth records may thus prove decisive. We analysed growth chronologies of common beech in two areas of contrasting nutritional
status in France. Dominant height growth was used as a proxy for productivity. Growth was compared between old and young paired
stands sampled at the same sites to factor out effects of ageing and site. Growth chronologies were estimated with a statistical
modelling procedure. The environmental causality of growth changes was addressed by combining (1) a comparison of growth changes
between regions, (2) a regional comparison of growth chronologies with chronologies of environmental factors and (3) growth–environment
relationships established from climate/soil data. Historical growth increases followed very similar courses in the two areas.
Remarkably, the magnitude of change was 50% lower in the area that had reduced nutritional status and nitrogen deposition.
Historical variations in environmental factors and growth were congruent with the roles of nitrogen availability and deposition,
and of atmospheric CO2 increase. Low-frequency variations in climate and growth were not coincident. However, our analysis demonstrated the role
of climatic anomalies in short-term growth variations. Growth–environment relationships further indicated a nitrogen constraint.
These observations corroborate the enhancing role of increased nitrogen availability on forest biomass accumulation previously
reported in ecosystem experiments and process-based modelling explorations. 相似文献
52.
Ling Chun Kong Bridget A. Holmes Aurelie Cotillard Fatiha Habi-Rachedi Rémi Brazeilles Sophie Gougis Nicolas Gausserès Patrice D. Cani Soraya Fellahi Jean-Philippe Bastard Sean P. Kennedy Joel Doré Stanislav Dusko Ehrlich Jean-Daniel Zucker Salwa W. Rizkalla Karine Clément 《PloS one》2014,9(10)
Background
Associations between dietary patterns, metabolic and inflammatory markers and gut microbiota are yet to be elucidated.Objectives
We aimed to characterize dietary patterns in overweight and obese subjects and evaluate the different dietary patterns in relation to metabolic and inflammatory variables as well as gut microbiota.Design
Dietary patterns, plasma and adipose tissue markers, and gut microbiota were evaluated in a group of 45 overweight and obese subjects (6 men and 39 women). A group of 14 lean subjects were also evaluated as a reference group.Results
Three clusters of dietary patterns were identified in overweight/obese subjects. Cluster 1 had the least healthy eating behavior (highest consumption of potatoes, confectionary and sugary drinks, and the lowest consumption of fruits that was associated also with low consumption of yogurt, and water). This dietary pattern was associated with the highest LDL cholesterol, plasma soluble CD14 (p = 0.01) a marker of systemic inflammation but the lowest accumulation of CD163+ macrophages with anti-inflammatory profile in adipose tissue (p = 0.05). Cluster 3 had the healthiest eating behavior (lower consumption of confectionary and sugary drinks, and highest consumption of fruits but also yogurts and soups). Subjects in this Cluster had the lowest inflammatory markers (sCD14) and the highest anti-inflammatory adipose tissue CD163+ macrophages. Dietary intakes, insulin sensitivity and some inflammatory markers (plasma IL6) in Cluster 3 were close to those of lean subjects. Cluster 2 was in-between clusters 1 and 3 in terms of healthfulness. The 7 gut microbiota groups measured by qPCR were similar across the clusters. However, the healthiest dietary cluster had the highest microbial gene richness, as evaluated by quantitative metagenomics.Conclusion
A healthier dietary pattern was associated with lower inflammatory markers as well as greater gut microbiota richness in overweight and obese subjects.Trial Registration
ClinicalTrials.gov NCT01314690相似文献53.
Sodium- and potassium-activated adenosine triphosphatases (Na,K-ATPase) is the ubiquitous active transport system that maintains
the Na+ and K+ gradients across the plasma membrane by exchanging three intracellular Na+ ions against two extracellular K+ ions. In addition to the two cation binding sites homologous to the calcium site of sarcoplasmic and endoplasmic reticulum
calcium ATPase and which are alternatively occupied by Na+ and K+ ions, a third Na+-specific site is located close to transmembrane domains 5, 6 and 9, and mutations close to this site induce marked alterations
of the voltage-dependent release of Na+ to the extracellular side. In the absence of extracellular Na+ and K+, Na,K-ATPase carries an acidic pH-activated, ouabain-sensitive “leak” current. We investigated the relationship between the
third Na+ binding site and the pH-activated current. The decrease (in E961A, T814A and Y778F mutants) or the increase (in G813A mutant)
of the voltage-dependent extracellular Na+ affinity was paralleled by a decrease or an increase in the pH-activated current, respectively. Moreover, replacing E961
with oxygen-containing side chain residues such as glutamine or aspartate had little effect on the voltage-dependent affinity
for extracellular Na+ and produced only small effects on the pH-activated current. Our results suggest that extracellular protons and Na+ ions share a high field access channel between the extracellular solution and the third Na+ binding site. 相似文献
54.
Mousset C Giraud A Provot O Hamze A Bignon J Liu JM Thoret S Dubois J Brion JD Alami M 《Bioorganic & medicinal chemistry letters》2008,18(11):3266-3271
A series of benzil derivatives related to combretastatin A-4 (CA-4) have been synthesized by oxidation of diarylalkynes promoted by PdI(2) in DMSO. Using this new protocol, 14 benzils were prepared in good to excellent yields and their biological activity has been delineated. Several benzils exhibited excellent antiproliferative activity: for example, 4j and 4k bearing the greatest resemblance to CA-4 and AVE-8062, respectively, were found to inhibit cell growth at the nanomolar level (20-50nM) on four human tumor cell lines. Flow cytometric analysis indicates that these compounds act as antimitotics and arrest the cell cycle in G(2)/M phase. A cell-based assay indicated that compounds 4j and 4k displayed a similar inhibition of tubulin assembly with an IC(50) value similar to CA-4. These results clearly demonstrated that the Z-double bond of CA-4 can be replaced by a 1,2-diketone unit without significant loss of cytotoxicity and inhibition of tubulin assembly potency. 相似文献
55.
The fold of small disulfide-rich proteins largely relies on two or more disulfide bridges that are main components of the hydrophobic core. Because of the small size of these proteins and their high cystine content, the cysteine connectivity has been difficult to ascertain in some cases, leading to uncertainties and debates in the literature. Here, we use molecular dynamics simulations and MM-PBSA free energy calculations to compare similar folds with different disulfide pairings in two disulfide-rich miniprotein families, namely the knottins and the short-chain scorpion toxins, for which the connectivity has been discussed. We first show that the MM-PBSA approach is able to discriminate the correct knotted topology of knottins from the laddered one. Interestingly, a comparison of the free energy components for kalata B1 and MCoTI-II suggests that cyclotides and squash inhibitors, although sharing the same scaffold, are stabilized through different interactions. Application to short-chain scorpion toxins suggests that the conventional cysteine pairing found in many homologous toxins is significantly more stable than the unconventional pairing reported for maurotoxin and for spinoxin. This would mean that native maurotoxin and spinoxin are not at the lowest free energy minimum and might result from kinetically rather than thermodynamically driven oxidative folding processes. For both knottins and toxins, the correct or conventional disulfide connectivities provide lower flexibilities and smaller deviations from the initial conformations. Overall, our work suggests that molecular dynamics simulations and the MM-PBSA approach to estimate free energies are useful tools to analyze and compare disulfide bridge connectivities in miniproteins. 相似文献
56.
57.
Human breast epithelial xenografts: An immunocytochemical and ultrastructural study of differentiation and lactogenic response 总被引:1,自引:0,他引:1
Jean-Daniel Dubois Michael J. O'Hare Paul Monaghan Jiri Bartek Robert Norris Barry A. Gusterson 《Differentiation; research in biological diversity》1987,35(1):72-82
Fragments of ductal and lobular epithelium ('organoids') produced by collagenase digestion of reduction-mammoplasty specimens were injected into athymic 'nude' mice. These heterospecific tissues were accepted without rejection, and the presence of xenografts was confirmed by cytology, immunocytochemistry and chromatin staining. Lactation, as confirmed by immunocytochemical and ultrastructural criteria, was observed in the grafted human epithelium during murine pregnancy at both intra- and extra-mammary sites. 相似文献
58.
Proteomics has changed the way proteins are analyzed in living systems. This approach has been applied to blood products and protein profiling has evolved in parallel with the development of techniques. The identification of proteins belonging to red blood cell, platelets or plasma was achieved at the end of the last century. Then, the questions on the applications emerged. Hence, several studies have focused on problems related to blood banking and products, such as the aging of blood products, identification of biomarkers, related diseases and the protein-protein interactions. More recently, a mass spectrometry-based proteomics approach to quality control has been applied in order to offer solutions and improve the quality of blood products. The current challenge we face is developing a closer relationship between transfusion medicine and proteomics. In this article, these issues will be approached by focusing first on the proteome identification of blood products and then on the applications and future developments within the field of proteomics and blood products. 相似文献
59.
Andre Aumelas Laurent Chiche Eve Mahe Dung Le-Nguyen
Philippe Sizun
Patrick Berthault Bruno Perly 《Neurochemistry international》1991,18(4):471-475Sarafotoxin-S6b has been synthesized and studied by 1H NMR in 50/50 acetonitrile/water mixture. All spin systems were identified and assigned with the aid of 2D experiments. On the basis of these data, a 3D structure of sarafotoxin is proposed and compared to that of [Nle7]endothelin obtained in the same conditions.
From this study, it appeared that sarafotoxin-S6b and [Nle7]endothelin roughly share the same 3D structure, the main differences being located in the 4–7 loop bearing the sequence variation. 相似文献
60.
The synthesis and thermotropic properties of 1,2-di-(9Z)-9-tetracosenoylphosphatidylcholine [delta 9-PC(24:1,24:1), 1], 1,2-di-(5Z)-5-tetracosenoylphosphatidylcholine [delta 5-PC(24:1,24:1), 2], and 1,2-di-(15Z)-15- tetracosenoylphosphatidylcholine [delta 15-PC(24:1,24:1), 3] are reported. Liposomes prepared from these phospholipids differ from those of the natural sponge phospholipids, 1,2-di-(5Z,9Z)-5,9-hexacosadienoylphosphatidylcholine (4a) and the corresponding ethanolamine (4b), both of which virtually exclude cholesterol from their bilayers. The behavior of 1 and 2 is similar to that of 1,2-di-(6Z,9Z)-6,9-hexacosadienoylphosphatidylcholine (5), which exhibits a partial molecular interaction with cholesterol. In the case of 3, cholesterol appears to interact with the saturated acyl chain regions of this phospholipid in a manner similar to that of its interaction with DPPC acyl chains. This study delineates the effect of the double-bond location in long fatty acyl chains of phospholipids on their interactions with cholesterol. 相似文献