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991.
Juan A. Godoy Macarena S. Arrázola Daniela Ordenes Carmen Silva-Alvarez Nady Braidy Nibaldo C. Inestrosa 《The Journal of biological chemistry》2014,289(52):36179-36193
The Wnt signaling pathway plays an important role in developmental processes, including embryonic patterning, cell specification, and cell polarity. Wnt components participate in the development of the central nervous system, and growing evidence indicates that this pathway also regulates the function of the adult nervous system. In this study, we report that Wnt-5a, a noncanonical Wnt ligand, is a potent activator of mitochondrial dynamics and induces acute fission and fusion events in the mitochondria of rat hippocampal neurons. The effect of Wnt-5a was inhibited in the presence of sFRP, a Wnt scavenger. Similarly, the canonical Wnt-3a ligand had no effect on mitochondrial fission-fusion events, suggesting that this effect is specific for Wnt-5a alone. We also show that the Wnt-5a effects on mitochondrial dynamics occur with an increase in both intracellular and mitochondrial calcium (Ca2+), which was correlated with an increased phosphorylation of Drp1(Ser-616) and a decrease of Ser-637 phosphorylation, both indicators of mitochondrial dynamics. Electron microscope analysis of hippocampal tissues in the CA1 region showed an increase in the number of mitochondria present in the postsynaptic region, and this finding correlated with a change in mitochondrial morphology. We conclude that Wnt-5a/Ca2+ signaling regulates the mitochondrial fission-fusion process in hippocampal neurons, a feature that might help to further understand the role of Wnt-related pathologies, including neurodegenerative diseases associated with mitochondrial dysfunction, and represents a potentially important link between impaired metabolic function and degenerative disorders. 相似文献
992.
993.
Cristina Peligero Jordi Argilaguet Roberto Güerri-Fernandez Berta Torres Carmen Ligero Pilar Colomer Montserrat Plana Hernando Knobel Felipe García Andreas Meyerhans 《PLoS pathogens》2015,11(12)
Blocking the PD-1/PD-L1 pathway has emerged as a potential therapy to restore impaired immune responses in human immunodeficiency virus (HIV)-infected individuals. Most reports have studied the impact of the PD-L1 blockade on effector cells and neglected possible effects on regulatory T cells (Treg cells), which play an essential role in balancing immunopathology and antiviral effector responses. The aim of this study was to define the consequences of ex vivo PD-L1 blockade on Treg cells from HIV-infected individuals. We observed that HIV infection led to an increase in PD-1+ and PD-L1+ Treg cells. This upregulation correlated with disease progression and decreased under antiretroviral treatment. Treg cells from viremic individuals had a particularly high PD-1 expression and impaired proliferative capacity in comparison with Treg cells from individuals under antiretroviral treatment. PD-L1 blockade restored the proliferative capacity of Treg cells from viremic individuals but had no effect on its suppressive capacity. Moreover, it increased the viral production in cell cultures from viremic individuals. This increase in viral production correlated with an increase in Treg cell percentage and a reduction in the CD4/Treg and CD8/Treg cell ratios. In contrast to the effect of the PD-L1 blockade on Treg cells from viremic individuals, we did not observe a significant effect on the proliferative capacity of Treg cells from individuals in whom viremia was controlled (either spontaneously or by antiretroviral treatment). However, PD-L1 blockade resulted in an increased proliferative capacity of HIV-specific-CD8 T cells in all subjects. Taken together, our findings suggest that manipulating PD-L1 in vivo can be expected to influence the net gain of effector function depending on the subject’s plasma viremia. 相似文献
994.
Daniel Balleza Carmen Quinto David Elias Froylán Gómez-Lagunas 《Archives of microbiology》2010,192(7):595-602
In this communication we reported the study of a cation channel present in the cytoplasmic membrane of the nitrogen fixing
bacterium Rhizobium etli. Inner-membrane (IM) vesicles were purified and fused into planar lipid bilayers (PLBs), under voltage clamp conditions.
We have found that fusion of IM-enriched vesicle fractions with these model membranes leads, mainly (>30% of 46 experiments),
to the reconstitution of high-conductance channels. Following this strategy, the activity of a channel with main open conductance
of 198 pS, in symmetrical 100 mM KCl, was recorded. The single-channel conductance increase to 653 pS in the presence of a
5:1 (cis to trans) gradient of KCl. The channel exhibits voltage dependency and a weak selectivity for cations showing a permeability ratios
of P
Rb/P
K = 0.96, P
Na/P
K = 0.07, and a conductance ratio of γRb/γK = 1.1. The channel here characterized represents a previously undescribed Rhizobium channel although its precise role in rhizobial physiology remains yet to be determined. 相似文献
995.
Hunting among Moka Bubis in Bioko: dynamics of faunal exploitation at the village level 总被引:1,自引:1,他引:0
Hunting by Bubi villages around Moka, Bioko, and their impact on the local prey fauna was studied during July–August, 1992. Questionnaires were sent to 45 known hunters in the region in order to find out their techniques and hunting procedures. Hunting trips were also followed (a total of 204 km covered) and counts of animals brought to the villages from 103 recorded trips were also made. There were two main hunting methods employed: trapping and shooting. Most commonly used was snare trapping. At least five different types were used during the study. Guns were less commonly employed. Both techniques are efficient and productive but prey caught by each method differed. Most animals caught by snares were large rodents (Atherurus africanus, Cricetomys emini) and small antelopes (Cephalophus monticola) whereas those shot were usually antelopes (C. monticola and C. ogilbyi), monkeys (Cercopithecus spp.) and, when accompanied by dogs, drills (Mandrillus leucophaeus). The effects of hunting in the region is acute especially since they incur upon the proclaimed protected areas in the south of the island. Hunting trips are gradually being lengthened and areas which were originally unaffected by this activity are now part of the villages' hunting zones. 相似文献
996.
997.
998.
Sophie Monsarrat Simon Benhamou Fran?ois Sarrazin Carmen Bessa-Gomes Willem Bouten Olivier Duriez 《PloS one》2013,8(1)
Feeding stations are commonly used to sustain conservation programs of scavengers but their impact on behaviour is still debated. They increase the temporal and spatial predictability of food resources while scavengers have supposedly evolved to search for unpredictable resources. In the Grands Causses (France), a reintroduced population of Griffon vultures Gyps fulvus can find carcasses at three types of sites: 1. “light feeding stations”, where farmers can drop carcasses at their farm (spatially predictable), 2. “heavy feeding stations”, where carcasses from nearby farms are concentrated (spatially and temporally predictable) and 3. open grasslands, where resources are randomly distributed (unpredictable). The impact of feeding stations on vulture’s foraging behaviour was investigated using 28 GPS-tracked vultures. The average home range size was maximal in spring (1272±752 km2) and minimal in winter (473±237 km2) and was highly variable among individuals. Analyses of home range characteristics and feeding habitat selection via compositional analysis showed that feeding stations were always preferred compared to the rest of the habitat where vultures can find unpredictable resources. Feeding stations were particularly used when resources were scarce (summer) or when flight conditions were poor (winter), limiting long-ranging movements. However, when flight conditions were optimal, home ranges also encompassed large areas of grassland where vultures could find unpredictable resources, suggesting that vultures did not lose their natural ability to forage on unpredictable resources, even when feeding stations were available. However during seasons when food abundance and flight conditions were not limited, vultures seemed to favour light over heavy feeding stations, probably because of the reduced intraspecific competition and a pattern closer to the natural dispersion of resources in the landscape. Light feeding stations are interesting tools for managing food resources, but don’t prevent vultures to feed at other places with possibly high risk of intoxication (poison). 相似文献
999.
James K. Nuñez Jin Chen Greg C. Pommier J. Zachery Cogan Joseph M. Replogle Carmen Adriaens Gokul N. Ramadoss Quanming Shi King L. Hung Avi J. Samelson Angela N. Pogson James Y.S. Kim Amanda Chung Manuel D. Leonetti Howard Y. Chang Martin Kampmann Bradley E. Bernstein Volker Hovestadt Jonathan S. Weissman 《Cell》2021,184(9):2503-2519.e17
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1000.
A Xenogeneic-Free Protocol for Isolation and Expansion of Human Adipose Stem Cells for Clinical Uses