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121.
Kuczewski N Fuchs C Ferrand N Jovanovic JN Gaiarsa JL Porcher C 《Journal of neurochemistry》2011,118(4):533-545
Recent studies have shown that GABA(B) receptors play more than a classical inhibitory role and can function as an important synaptic maturation signal early in life. In a previous study, we reported that GABA(B) receptor activation triggers secretion of brain-derived neurotrophic factor (BDNF) and promotes the functional maturation of GABAergic synapses in the developing rat hippocampus. To identify the signalling pathway linking GABA(B) receptor activation to BDNF secretion in these cells, we have now used the phosphorylated form of the cAMP response element-binding protein as a biological sensor for endogenous BDNF release. In the present study, we show that GABA(B) receptor-induced secretion of BDNF relies on the activation of phospholipase C, followed by the formation of diacylglycerol, activation of protein kinase C, and the opening of L-type voltage-dependent Ca(2+) channels. We further show that once released by GABA(B) receptor activation, BDNF increases the membrane expression of β(2/3) -containing GABA(A) receptors in neuronal cultures. These results reveal a novel function of GABA(B) receptors in regulating the expression of GABA(A) receptor through BDNF-tropomyosin-related kinase B receptor dependent signalling pathway. 相似文献
122.
van der Linden AM Moorman C Cuppen E Korswagen HC Plasterk RH 《Current biology : CB》2003,13(6):516-521
The G(12) type of heterotrimeric G-proteins play an important role in development and behave as potent oncogenes in cultured cells. However, little is known about the molecular nature of the components that act in the G(12)-signaling pathway in an organism. We characterized a C. elegans Galpha subunit gene, gpa-12, which is a homolog of mammalian G(12)/G(13)alpha, and found that animals defective in gpa-12 are viable. Expression of activated GPA-12 (G(12)QL) results in a developmental growth arrest caused by a feeding behavior defect that is due to a dramatic reduction in pharyngeal pumping. To elucidate the molecular nature of the signaling pathways in which G(12) participates, we screened for suppressors of the G(12)QL phenotype. We isolated 50 suppressors that contain mutations in tpa-1, which encodes two protein kinase C isoforms, TPA-1A and TPA-1B, most similar to PKCtheta/delta. TPA-1 mediates the action of the tumor promoter PMA. Expression of G(12)QL and treatment of wild-type animals with PMA induce an identical growth arrest caused by inhibition of larval feeding, which is dependent on TPA-1A and TPA-1B function. These results suggest that TPA-1 is a downstream target of both G(12) signaling and PMA in modulating feeding and growth in C. elegans. Taken together, our findings provide a potential molecular mechanism for the transforming capability of G(12) proteins. 相似文献
123.
Sebastien Havard Celine Peissier Sergine Ponsard Erick D. M. Campan 《Insect Science》2014,21(1):93-102
Two cornborer species, Ostrinia furnacalis (Lepidoptera: Crambidae) and O. nubilalis, are major corn pests in Asia and Europe, respectively. In both continents, the larval endoparasitoid Macrocentrus cingulum (Hymenoptera: Braconidae) develops on another, closely related stemborer, O. scapulalis, which feeds on mugwort and other dicotyledons. M. cingulum also emerges from O. furnacalis in Asia and (9. nubilalis in North America, but not from O. nubilalis in Europe. We assessed the ability of three populations of each of the three Ostrinia species to encapsulate foreign bodies of a size similar to that of a M. cingulum egg. We conclude that variations in encapsulation ability alone cannot account for the differences observed in the field between parasite emergence rates in these different host species and geographic areas. 相似文献
124.
Peter Keov Laura López Shane M. Devine Celine Valant J. Robert Lane Peter J. Scammells Patrick M. Sexton Arthur Christopoulos 《The Journal of biological chemistry》2014,289(34):23817-23837
TBPB and 77-LH-28-1 are selective agonists of the M1 muscarinic acetylcholine receptor (mAChR) that may gain their selectivity through a bitopic mechanism, interacting concomitantly with the orthosteric site and part of an allosteric site. The current study combined site-directed mutagenesis, analytical pharmacology,and molecular modeling to gain further insights into the structural basis underlying binding and signaling by these agonists. Mutations within the orthosteric binding site caused similar reductions in affinity and signaling efficacy for both selective and prototypical orthosteric ligands. In contrast, the mutation of residues within transmembrane helix (TM) 2 and the second extracellular loop (ECL2) discriminated between the different classes of ligand. In particular, ECL2 appears to be involved in the selective binding of bitopic ligands and in coordinating biased agonism between intracellular calcium mobilization and ERK1/2 phosphorylation. Molecular modeling of the interaction between TBPB and the M1 mAChR revealed a binding pose predicted to extend from the orthosteric site up toward a putative allosteric site bordered by TM2, TM3, and TM7, thus consistent with a bitopic mode of binding. Overall, these findings provide valuable structural and mechanistic insights into bitopic ligand actions and receptor activation and support a role for ECL2 in dictating the active states that can be adopted by a G protein-coupled receptor. This may enable greater selective ligand design and development for mAChRs and facilitate improved identification of bitopic ligands. 相似文献
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126.
Purina Ingrida Balode Maija Béchemin Christian Põder Tõnis Vérité Celine Maestrini Serge 《Hydrobiologia》2004,514(1-3):127-137
Hydrobiologia - A mesocosm experiment was used to investigate the effect of terrestrial-origin dissolved organic matter (DOM) on the development of dinoflagellates in natural summer phytoplankton... 相似文献
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128.
Mathieu Gautier Junichi Yamaguchi Julien Foucaud Anne Loiseau Aurélien Ausset Benoit Facon Bernhard Gschloessl Jacques Lagnel Etienne Loire Hugues Parrinello Dany Severac Celine Lopez-Roques Cecile Donnadieu Maxime Manno Helene Berges Karim Gharbi Lori Lawson-Handley Lian-Sheng Zang Benjamin Prud’homme 《Current biology : CB》2018,28(20):3296-3302.e7
129.
Celine T. Goulet Marcus Michelangeli Melinda Chung Julia L. Riley Bob B. M. Wong Michael B. Thompson David G. Chapple 《Evolutionary ecology》2018,32(5):469-488
The pace-of-life syndrome (POLS) suggests that behavioral traits are correlated and integrate within a fast–slow physiological continuum. At the fast extreme, individuals having higher metabolic rates are more active, exploratory, and bold with the opposite suite of traits characterizing those at the slow physiological extreme. A recent framework suggests that behavioral types may also differ consistently in their cognitive style. Accordingly, we propose that cognition could be further incorporated into the POLS framework comprised of behavioral and thermal physiological traits. Under this premise, fast behavioral types having high thermal traits are predicted to acquire a novel task faster but at the cost of accuracy while slow behavioral types with low thermal traits would be more attentive, responding to cues at a slower rate leading to higher accuracy and flexibility. This was tested by measuring physiological and behavioral traits in delicate skinks (Lampropholis delicata) and testing their learning ability. Correlations were detected between cognition and behavior but not thermal physiology. Contrary to our predictions, individual positioning along these axes opposed our predicted directions along the fast–slow continuum. Fast lizards preferring lower body temperatures expressed higher activity, exploration, sociality, and boldness levels, and learned the discrimination learning task at a slower rate but made the most errors. Additionally, modelling results indicated that neither thermal physiology, behavior, or their interaction influenced cognitive performance. Although the small number of animals completing the final stages of the learning assays limits the strength of these findings. Thus, we propose that future research involving a greater sample size and number of trials be conducted so as to enhance our understanding into how the integration of cognitive style, behavior, and physiology may influence individual fitness within natural populations. 相似文献
130.