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991.
992.
993.
Eklöf JS Alsterberg C Havenhand JN Sundbäck K Wood HL Gamfeldt L 《Ecology letters》2012,15(8):864-872
Ecosystems are simultaneously affected by biodiversity loss and climate change, but we know little about how these factors interact. We predicted that climate warming and CO (2) -enrichment should strengthen trophic cascades by reducing the relative efficiency of predation-resistant herbivores, if herbivore consumption rate trades off with predation resistance. This weakens the insurance effect of herbivore diversity. We tested this prediction using experimental ocean warming and acidification in seagrass mesocosms. Meta-analyses of published experiments first indicated that consumption rate trades off with predation resistance. The experiment then showed that three common herbivores together controlled macroalgae and facilitated seagrass dominance, regardless of climate change. When the predation-vulnerable herbivore was excluded in normal conditions, the two resistant herbivores maintained top-down control. Under warming, however, increased algal growth outstripped control by herbivores and the system became algal-dominated. Consequently, climate change can reduce the relative efficiency of resistant herbivores and weaken the insurance effect of biodiversity. 相似文献
994.
Children respond positively to individuals who favor them and also to individuals who are fair. The present studies examine the interaction between these two preferences by presenting children with two distributors who share resources with the child participant and another recipient. Children are asked whom they like better: the distributor who was unfair but favored the child participant or the distributor who was fair and showed no (or reduced) favoritism. In Study 1, we find that when fairness and favoritism are in conflict, children are split on whom they prefer. In Study 2, we find that placing children in a competitive context leads to a stronger preference for the distributor who favored the child participant. In Study 3, we examine whether children's preference for favoritism persists when both distributors gave the child the same number of rewards, but one distributor gave the child participant relatively more than the other recipient. In this situation, we find that children prefer the fair distributor. However, we again find that creating a competitive context reduces children's preference for the fair distributor. Finally we find that in a third-party context, children value fairness over generosity. Taken together, these results show how children balance competing concerns for fairness and favoritism. 相似文献
995.
The brain function depends on a continuous supply of blood. The blood–brain barrier (BBB), which is formed by vascular cells
and glia, separates components of the circulating blood from neurons and maintains the precisely regulated brain milieu required
for proper neuronal function. A compromised BBB alters the transport of molecules between the blood and brain and has been
associated with or shown to precede neurodegenerative disease. Blood components immediately leak into the brain after mechanical
damage or as a consequence of a compromised BBB in brain disease changing the extracellular environment at sites of vascular
damage. It is intriguing how blood-derived components alter the cellular and molecular constituents of the neurovascular interface
after BBB opening. We recently identified an unexpected role for the blood protein fibrinogen, which is deposited in the nervous
system promptly after vascular damage, as an initial scar inducer by promoting the availability of active TGF-β. Fibrinogen-bound
latent TGF-β interacts with astrocytes, leading to active TGF-β formation and activation of the TGF-β/Smad signaling pathway.
Here, we discuss the pleiotropic effects of potentially vascular-derived TGF-β on cells at the neurovascular interface and
we speculate how these biological effects might contribute to degeneration and regeneration processes. Summarizing the effects
of the components derived from the brain vascular system on nervous system regeneration might support the development of new
therapeutic approaches. 相似文献
996.
997.
Jaime Palma Sree C. Yaddanapudi Lucy Pigati Mallory A. Havens Sarah Jeong Geoffrey A. Weiner Kristina Mary Ellen Weimer Brittany Stern Michelle L. Hastings Dominik M. Duelli 《Nucleic acids research》2012,40(18):9125-9138
MicroRNAs (miRNAs) are released from cells in association with proteins or microvesicles. We previously reported that malignant transformation changes the assortment of released miRNAs by affecting whether a particular miRNA species is released or retained by the cell. How this selectivity occurs is unclear. Here we report that selectively exported miRNAs, whose release is increased in malignant cells, are packaged in structures that are different from those that carry neutrally released miRNAs (n-miRNAs), whose release is not affected by malignancy. By separating breast cancer cell microvesicles, we find that selectively released miRNAs associate with exosomes and nucleosomes. However, n-miRNAs of breast cancer cells associate with unconventional exosomes, which are larger than conventional exosomes and enriched in CD44, a protein relevant to breast cancer metastasis. Based on their large size, we call these vesicles L-exosomes. Contrary to the distribution of miRNAs among different microvesicles of breast cancer cells, normal cells release all measured miRNAs in a single type of vesicle. Our results suggest that malignant transformation alters the pathways through which specific miRNAs are exported from cells. These changes in the particles and their miRNA cargo could be used to detect the presence of malignant cells in the body. 相似文献
998.
Christian B. Gerhold Duane D. Winkler Kristina Lakomek Florian U. Seifert Sebastian Fenn Brigitte Kessler Gregor Witte Karolin Luger Karl-Peter Hopfner 《Nucleic acids research》2012,40(21):11036-11046
Nuclear actin-related proteins (Arps) are subunits of several chromatin remodelers, but their molecular functions within these complexes are unclear. We report the crystal structure of the INO80 complex subunit Arp8 in its ATP-bound form. Human Arp8 has several insertions in the conserved actin fold that explain its inability to polymerize. Most remarkably, one insertion wraps over the active site cleft and appears to rigidify the domain architecture, while active site features shared with actin suggest an allosterically controlled ATPase activity. Quantitative binding studies with nucleosomes and histone complexes reveal that Arp8 and the Arp8–Arp4–actin-HSA sub-complex of INO80 strongly prefer nucleosomes and H3–H4 tetramers over H2A–H2B dimers, suggesting that Arp8 functions as a nucleosome recognition module. In contrast, Arp4 prefers free (H3–H4)2 over nucleosomes and may serve remodelers through binding to (dis)assembly intermediates in the remodeling reaction. 相似文献
999.
We have identified in the literature variants in 64 genes that may be involved in gene-obesity-behaviour interactions. Personalisation of behaviourally based preventive approaches against obesity seems feasible, however obesity genomics is still in the discovery phase of translational research and abundant replication studies are needed before these largely pioneering findings can be extended to practice and population impact. Automation of search algorithms and development of more efficient tools for knowledge synthesis of genomic research into gene-obesity-behaviour interactions might facilitate the advent of widely available personalised prevention approaches. Our future efforts shall therefore concentrate on developing such tools, as well as a research repository dedicated to the use of public health genomics for obesity control. 相似文献
1000.
Milanović SM Ivanković D Fister K Poljicanin T Brecić P Vuletić S 《Collegium antropologicum》2012,36(Z1):117-123
The aim of this study was to examine the social conditioning of health behaviors of adults in Croatia, based on the data from Croatian Adult Health Survey 2003. This cross-sectional study on a representative random sample of 9070 Croatian adults showed that obesity was significantly and socially conditioned in women, whereas for men the indication of social conditioning has not reached a statistically significant level. Health behaviors were socially conditioned in both sexes. Men's living habits were more irregular than those of women. Compared with women, men consumed more cured meat products, consumed alcohol excessivelly and smoked cigarettes more often, whereas they ate less fruits and vegetables. Health promotion strategies based on the behavioral correlates of overweight and obesity are needed to prevent excess weight gain in the Croatian population. While for men a unique educational model is applicable, women require more specialized programs, adapted to their social background. 相似文献