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1.
Ecol Lett ; 25(3): 581-597, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35199922

RESUMO

Functional traits offer a rich quantitative framework for developing and testing theories in evolutionary biology, ecology and ecosystem science. However, the potential of functional traits to drive theoretical advances and refine models of global change can only be fully realised when species-level information is complete. Here we present the AVONET dataset containing comprehensive functional trait data for all birds, including six ecological variables, 11 continuous morphological traits, and information on range size and location. Raw morphological measurements are presented from 90,020 individuals of 11,009 extant bird species sampled from 181 countries. These data are also summarised as species averages in three taxonomic formats, allowing integration with a global phylogeny, geographical range maps, IUCN Red List data and the eBird citizen science database. The AVONET dataset provides the most detailed picture of continuous trait variation for any major radiation of organisms, offering a global template for testing hypotheses and exploring the evolutionary origins, structure and functioning of biodiversity.


Assuntos
Aves , Ecossistema , Animais , Biodiversidade , Evolução Biológica , Humanos , Filogenia
2.
J Neurophysiol ; 125(1): 184-198, 2021 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-33206577

RESUMO

Small alterations in extracellular H+ can profoundly alter neurotransmitter release by neurons. We examined mechanisms by which extracellular ATP induces an extracellular H+ flux from Müller glial cells, which surround synaptic connections throughout the vertebrate retina. Müller glia were isolated from tiger salamander retinae and H+ fluxes examined using self-referencing H+-selective microelectrodes. Experiments were performed in 1 mM HEPES with no bicarbonate present. Replacement of extracellular sodium by choline decreased H+ efflux induced by 10 µM ATP by 75%. ATP-induced H+ efflux was also reduced by Na+/H+ exchange inhibitors. Amiloride reduced H+ efflux initiated by 10 µM ATP by 60%, while 10 µM cariporide decreased H+ flux by 37%, and 25 µM zoniporide reduced H+ flux by 32%. ATP-induced H+ fluxes were not significantly altered by the K+/H+ pump blockers SCH28080 or TAK438, and replacement of all extracellular chloride with gluconate was without effect on H+ fluxes. Recordings of ATP-induced H+ efflux from cells that were simultaneously whole cell voltage clamped revealed no effect of membrane potential from -70 mV to 0 mV. Restoration of extracellular potassium after cells were bathed in 0 mM potassium produced a transient alteration in ATP-dependent H+ efflux. The transient response to extracellular potassium occurred only when extracellular sodium was present and was abolished by 1 mM ouabain, suggesting that alterations in sodium gradients were mediated by Na+/K+-ATPase activity. Our data indicate that the majority of H+ efflux elicited by extracellular ATP from isolated Müller cells is mediated by Na+/H+ exchange.NEW & NOTEWORTHY Glial cells are known to regulate neuronal activity, but the exact mechanism(s) whereby these "support" cells modulate synaptic transmission remains unclear. Small changes in extracellular levels of acidity are known to be particularly powerful regulators of neurotransmitter release. Here, we show that extracellular ATP, known to be a potent activator of glial cells, induces H+ efflux from retinal Müller (glial) cells and that the bulk of the H+ efflux is mediated by Na+/H+ exchange.


Assuntos
Trifosfato de Adenosina/metabolismo , Células Ependimogliais/metabolismo , Prótons , Trocadores de Sódio-Hidrogênio/metabolismo , Potenciais de Ação , Animais , Células Cultivadas , Células Ependimogliais/fisiologia , Imidazóis/farmacologia , Transporte de Íons , Pirróis/farmacologia , Trocadores de Sódio-Hidrogênio/antagonistas & inibidores , ATPase Trocadora de Sódio-Potássio/antagonistas & inibidores , ATPase Trocadora de Sódio-Potássio/metabolismo , Sulfonamidas/farmacologia , Urodelos
3.
Langmuir ; 26(6): 3972-4, 2010 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-20017490

RESUMO

The effect on 2D molecular crystallization caused by the addition of propylthioether side groups to the 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) molecule is investigated using scanning tunneling microscopy (STM). The molecule was deposited from 1-phenyloctane onto highly oriented pyrolytic graphite (HOPG) and imaged at the liquid-solid interface. We observe a different structure to previously reported arrangements of PTCDA due to the presence of the propylthioether side groups which inhibits the formation of the herringbone phase. A model, supported by calculations based on density functional theory, is proposed in which molecules form rows stabilized by hydrogen bonding.

5.
Chem Commun (Camb) ; 48(12): 1751-3, 2012 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-22215090

RESUMO

The redox processes associated with BODIPY analogues are studied by electrochemical and spectroscopic methods revealing a characteristic profile for the persistent BODIPY radical and quenching of fluorescence upon reduction.

6.
Chem Commun (Camb) ; 46(16): 2775-7, 2010 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-20369179

RESUMO

A unimolecular hydrogen-bonded network is formed by a perylene-diimide derivative following surface self-assembly leading to the formation of pores of appropriate dimensions to accommodate regularly spaced guest C(60) molecules.

7.
Chemistry ; 14(25): 7600-7, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18666294

RESUMO

Controlled self-assembly and chemical tailoring of bimolecular networks on surfaces is demonstrated using structural derivatives of 3,4:9,10-perylenetetracarboxylic diimide (PTCDI) combined with melamine (1,3,5-triazine-2,4,6-triamine). Two functionalised PTCDI derivatives have been synthesised, Br(2)-PTCDI and di(propylthio)-PTCDI, through attachment of chemical side groups to the perylene core. Self-assembled structures formed by these molecules on a Ag-Si(111)sqrt3 x sqrt3R30 degrees surface were studied with a room-temperature scanning tunneling microscope under ultrahigh vacuum conditions. It is shown that the introduction of side groups can have a significant effect upon both the structures formed, notably in the case of di(propylthio)-PTCDI which forms a previously unreported unimolecular hexagonal arrangement, and their entrapment behaviour. These results demonstrate a new route of functionalisation for network pores, opening up the possibility of designing nanostructured surface structures with chemical selectivity and applications in nanostructure templating.


Assuntos
Nanoestruturas/química , Perileno/análogos & derivados , Triazinas/química , Substâncias Macromoleculares/química , Estrutura Molecular , Tamanho da Partícula , Perileno/síntese química , Perileno/química , Porosidade , Silício/química , Prata/química , Propriedades de Superfície , Temperatura
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