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排序方式: 共有1192条查询结果,搜索用时 46 毫秒
901.
Cecilia Nilsson Adriaan M. Dokter Liesbeth Verlinden Judy Shamoun‐Baranes Baptiste Schmid Peter Desmet Silke Bauer Jason Chapman Jose A. Alves Phillip M. Stepanian Nir Sapir Charlotte Wainwright Mathieu Boos Anna Grska Myles H. M. Menz Pedro Rodrigues Hidde Leijnse Pavel Zehtindjiev Robin Brabant Günther Haase Nadja Weisshaupt Micha Ciach Felix Liechti 《Ecography》2019,42(5):876-886
Nocturnal avian migration flyways remain an elusive concept, as we have largely lacked methods to map their full extent. We used the network of European weather radars to investigate nocturnal bird movements at the scale of the European flyway. We mapped the main migration directions and showed the intensity of movement across part of Europe by extracting biological information from 70 weather radar stations from northern Scandinavia to Portugal, during the autumn migration season of 2016. On average, over the 20 nights and all sites, 389 birds passed per 1 km transect per hour. The night with highest migration intensity showed an average of 1621 birds km–1 h–1 passing the radar stations, but there was considerable geographical and temporal variation in migration intensity. The highest intensity of migration was seen in central France. The overall migration directions showed strong southwest components. Migration dynamics were strongly related to synoptic wind conditions. A wind‐related mass migration event occurred immediately after a change in wind conditions, but quickly diminished even when supporting winds continued to prevail. This first continental‐scale study using the European network of weather radars demonstrates the wealth of information available and its potential for investigating large‐scale bird movements, with consequences for ecosystem function, nutrient transfer, human and livestock health, and civil and military aviation. 相似文献
902.
Many insectivorous passerines become frugivorous during migration. Because water may facilitate the digestion of dry fruits, some passerines may benefit from staging in stopover sites that offer access to drinking water. In autumn, water consumption by blackcaps Sylvia atricapilla staging in Israel was found to induce a shift from insectivory to frugivory. We tested two alternative hypotheses concerning the mechanism facilitating consumption of the relatively dry fruits which are common in this region: 1) water intake facilitates the passage of fruits within the digestive tract when these two resources are simultaneously ingested, and 2) improved body water balance allows the consumption and ingestion of large amounts of dry fruits. Blackcaps were subjected to five treatments that included temporal separation of water and fruit consumption, as well as subcutaneous water injection to maintain balanced body water in water‐deprived birds. Fruit consumption rate was measured daily. We found that only simultaneous provisioning of water and fruits significantly increased fruit consumption rate, implying that drinking water directly improves fruit digestion within the digestive system. Furthermore, the fuel deposition rate increased with increased fruit consumption rate. These results emphasize the importance of water availability for the ecology and conservation of migrating passerines. 相似文献
903.
Yoav Elkis Shai Bel Roni Rahimi Tali Lerer-Goldstein Smadar Levin-Zaidman Tatiana Babushkin Sally Shpungin Uri Nir 《PloS one》2015,10(12)
TMF/ARA160 is known to be a TATA element Modulatory Factor (TMF). It was initially identified as a DNA-binding factor and a coactivator of the Androgen receptor. It was also characterized as a Golgi-associated protein, which is essential for acrosome formation during functional sperm development. However, the molecular roles of TMF in this intricate process have not been revealed. Here, we show that during spermiogenesis, TMF undergoes a dynamic change of localization throughout the Golgi apparatus. Specifically, TMF translocates from the cis-Golgi to the trans-Golgi network and to the emerging vesicles surface, as the round spermatids develop. Notably, lack of TMF led to an abnormal spatial orientation of the Golgi and to the deviation of the trans-Golgi surface away from the nucleus of the developing round spermatids. Concomitantly, pro-acrosomal vesicles derived from the TMF-/- Golgi lacked targeting properties and did not tether to the spermatid nuclear membrane thereby failing to form the acrosome anchoring scaffold, the acroplaxome, around the cell-nucleus. Absence of TMF also perturbed the positioning of microtubules, which normally lie in proximity to the Golgi and are important for maintaining Golgi spatial orientation and dynamics and for chromatoid body formation, which is impaired in TMF-/- spermatids. In-silico evaluation combined with molecular and electron microscopic analyses revealed the presence of a microtubule interacting domain (MIT) in TMF, and confirmed the association of TMF with microtubules in spermatogenic cells. Furthermore, the MIT domain in TMF, along with microtubules integrity, are required for stable association of TMF with the Golgi apparatus. Collectively, we show here for the first time that a Golgi and microtubules associated protein is crucial for maintaining proper Golgi orientation during a cell developmental process. 相似文献
904.
High‐Efficiency Organic Photovoltaic Cells Based on the Solution‐Processable Hole Transporting Interlayer Copper Thiocyanate (CuSCN) as a Replacement for PEDOT:PSS
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905.
Munseok S. Chae Hyojeong J. Kim Hyeri Bu Jeyne Lyoo Ran Attias Ben Dlugatch Matan Oliel Yosef Gofer Seung‐Tae Hong Doron Aurbach 《Liver Transplantation》2020,10(21)
Tunnel‐type sodium manganese oxide is a promising cathode material for aqueous/nonaqueous sodium‐ion batteries, however its storage mechanism is not fully understood, in part due to the complicated sodium intercalation process. In addition, low cyclability due to manganese dissolution has limited its practical application in rechargeable batteries. Here, the intricate sodium intercalation mechanism of Na0.44MnO2 is revealed by combination of electrochemical characterization, structure determination from powder X‐ray diffraction data, 3D bond valence difference maps, and barrier‐energy calculations of the sodium diffusion. NaI is proposed as an important electrolyte solution additive. It is shown to form a thin, beneficial, and durable cathode surface film that prevents manganese dissolution. The addition of 0.01 m NaI to electrolyte solutions based on alkyl carbonate solvents and NaClO4 greatly improves the cycling efficiency, raising the capacity retention from 86% to 96% after 600 cycles. This study determines the core aspects of the sodium intercalation mechanism in tunnel‐type sodium manganese oxide and shows how it can serve as a durable cathode material for rechargeable Na batteries. 相似文献
906.
Ruddi Rodríguez-García Iván López-Montero Michael Mell Gustavo Egea Nir?S. Gov Francisco Monroy 《Biophysical journal》2015,108(12):2794-2806
Erythrocytes are flexible cells specialized in the systemic transport of oxygen in vertebrates. This physiological function is connected to their outstanding ability to deform in passing through narrow capillaries. In recent years, there has been an influx of experimental evidence of enhanced cell-shape fluctuations related to metabolically driven activity of the erythroid membrane skeleton. However, no direct observation of the active cytoskeleton forces has yet been reported to our knowledge. Here, we show experimental evidence of the presence of temporally correlated forces superposed over the thermal fluctuations of the erythrocyte membrane. These forces are ATP-dependent and drive enhanced flickering motions in human erythrocytes. Theoretical analyses provide support for a direct force exerted on the membrane by the cytoskeleton nodes as pulses of well-defined average duration. In addition, such metabolically regulated active forces cause global membrane softening, a mechanical attribute related to the functional erythroid deformability. 相似文献
907.
Giovanni Monaco Elke Decrock Nir Arbel Alexander R. van Vliet Rita M. La Rovere Humbert De Smedt Jan B. Parys Patrizia Agostinis Luc Leybaert Varda Shoshan-Barmatz Geert Bultynck 《The Journal of biological chemistry》2015,290(14):9150-9161
Excessive Ca2+ fluxes from the endoplasmic reticulum to the mitochondria result in apoptotic cell death. Bcl-2 and Bcl-XL proteins exert part of their anti-apoptotic function by directly targeting Ca2+-transport systems, like the endoplasmic reticulum-localized inositol 1,4,5-trisphosphate receptors (IP3Rs) and the voltage-dependent anion channel 1 (VDAC1) at the outer mitochondrial membranes. We previously demonstrated that the Bcl-2 homology 4 (BH4) domain of Bcl-2 protects against Ca2+-dependent apoptosis by binding and inhibiting IP3Rs, although the BH4 domain of Bcl-XL was protective independently of binding IP3Rs. Here, we report that in contrast to the BH4 domain of Bcl-2, the BH4 domain of Bcl-XL binds and inhibits VDAC1. In intact cells, delivery of the BH4-Bcl-XL peptide via electroporation limits agonist-induced mitochondrial Ca2+ uptake and protects against staurosporine-induced apoptosis, in line with the results obtained with VDAC1−/− cells. Moreover, the delivery of the N-terminal domain of VDAC1 as a synthetic peptide (VDAC1-NP) abolishes the ability of BH4-Bcl-XL to suppress mitochondrial Ca2+ uptake and to protect against apoptosis. Importantly, VDAC1-NP did not affect the ability of BH4-Bcl-2 to suppress agonist-induced Ca2+ release in the cytosol or to prevent apoptosis, as done instead by an IP3R-derived peptide. In conclusion, our data indicate that the BH4 domain of Bcl-XL, but not that of Bcl-2, selectively targets VDAC1 and inhibits apoptosis by decreasing VDAC1-mediated Ca2+ uptake into the mitochondria. 相似文献
908.
In many aquatic environments the essential micronutrient iron is predominantly complexed by a heterogeneous pool of strong organic chelators. Research on iron uptake mechanisms of cyanobacteria inhabiting these environments has focused on endogenous siderophore production and internalization. However, as many cyanobacterial species do not produce siderophores, alternative Fe acquisition mechanisms must exist. Here we present a study of the iron uptake pathways in the unicellular, planktonic, non-siderophore producing strain Synechocystis sp. PCC 6803. By applying trace metal clean techniques and a chemically controlled growth medium we obtained reliable and reproducible short-term (radioactive assays) and long-term (growth experiments) iron uptake rates. We found that Synechocystis 6803 is capable of acquiring iron from exogenous ferrisiderophores (Ferrioxamine-B, FeAerobactin) and that unchelated, inorganic Fe is a highly available source of iron. Inhibition of iron uptake by the Fe(II)-specific ligand, ferrozine, indicated that reduction of both inorganic iron and ferrisiderophore complexes occurs before transport through the plasma membrane. Measurements of iron reduction rates and the inhibitory effect of ferrozine on growth supported this conclusion. The reduction-based uptake strategy is well suited for acquiring iron from multiple complexes in dilute aquatic environments and may play an important role in other cyanobacterial strains. 相似文献
909.
Adva Levy-Barda Yaniv Lerenthal Anthony J Davis Young Min Chung Jeroen Essers Zhengping Shao Nicole van Vliet David J Chen Mickey C-T Hu Roland Kanaar Yael Ziv Yosef Shiloh 《Cell cycle (Georgetown, Tex.)》2011,10(24):4300-4310
The DNA damage response (DDR) is a complex signaling network that leads to damage repair while modulating numerous cellular processes. DNA double-strand breaks (DSBs), a highly cytotoxic DNA lesion, activate this system most vigorously. The DSB response network is orchestrated by the ATM protein kinase, which phosphorylates key players in its various branches. Proteasome-mediated protein degradation plays an important role in the proteome dynamics following DNA damage induction. Here, we identify the nuclear proteasome activator PA28γ (REGγ; PSME3) as a novel DDR player. PA28γ depletion leads to cellular radiomimetic sensitivity and a marked delay in DSB repair. Specifically, PA28γ deficiency abrogates the balance between the two major DSB repair pathways—nonhomologous end-joining and homologous recombination repair. Furthermore, PA28γ is found to be an ATM target, being recruited to the DNA damage sites and required for rapid accumulation of proteasomes at these sites. Our data reveal a novel ATM-PA28γ-proteasome axis of the DDR that is required for timely coordination of DSB repair.Key words: genomic stability, DNA repair, double-strand breaks, ATM, proteasome, PA28γ (PSME3) 相似文献
910.
London N Lamphear CL Hougland JL Fierke CA Schueler-Furman O 《PLoS computational biology》2011,7(10):e1002170
Farnesylation is an important post-translational modification catalyzed by farnesyltransferase (FTase). Until recently it was believed that a C-terminal CaaX motif is required for farnesylation, but recent experiments have revealed larger substrate diversity. In this study, we propose a general structural modeling scheme to account for peptide binding specificity and recapitulate the experimentally derived selectivity profile of FTase in vitro. In addition to highly accurate recovery of known FTase targets, we also identify a range of novel potential targets in the human genome, including a new substrate class with an acidic C-terminal residue (CxxD/E). In vitro experiments verified farnesylation of 26/29 tested peptides, including both novel human targets, as well as peptides predicted to tightly bind FTase. This study extends the putative range of biological farnesylation substrates. Moreover, it suggests that the ability of a peptide to bind FTase is a main determinant for the farnesylation reaction. Finally, simple adaptation of our approach can contribute to more accurate and complete elucidation of peptide-mediated interactions and modifications in the cell. 相似文献