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Auteur Mary Beilby |
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trié(s) par (Pertinence décroissant(e), Titre croissant(e)) Affiner la rechercheThe role of H+/OH channels in saline pathology of Chara australis : brief history / Mary Beilby in Botany letters, vol. 165, n°1 (Année 2018)
Titre : The role of H+/OH channels in saline pathology of Chara australis : brief history Type de document : texte imprimé Auteurs : Mary Beilby, Auteur ; Virginia Shepherd, Auteur ; Marketa Absolonova, Auteur Année de publication : 2018 Article en page(s) : pp. 45-54 Langues : Anglais (eng) Mots-clés : H+/OH channels  Chara australis  salinity stress current-voltage characteristics  membrane potential difference noise  fluorescent pH measurement Résumé : "The pH banding pattern, observed in Chara and Nitella early last century, suggests that there are H+ or OH− conducting channels in the alkaline bands of the characean plasma membrane. If the cells are exposed to high pH medium, pHo, these channels become the dominant membrane conductance: High pH state. Goldman-Hodgkin-Katz (GHK) equation can model the current-voltage (I/V) characteristics of this state with either H+ or OH− as permeant ion. However, H+ requires unrealistically large increases in channel conductance/number parameter as pHo increases. Recently we discovered a typical spiky noise in the membrane potential difference (PD) of salt sensitive Chara australis, appearing immediately upon exposure to saline. The H+/OH− channels are thought to open transiently in small patches all over the cell, while negative membrane PD does not support their open state/s. As the membrane PD depolarizes due to inhibition of the proton pump by salinity, the H+/OH− channels remain open to dominate the I/V characteristics, which can also be modeled by GHK equation. The addition of 1 mM ZnCl2, the main known blocker of animal H+ channels, abolishes both the PD noise and the H+/OH− I/V characteristics in high pH state and in salt stressed cells. Confocal microscopy and fluorescein isothiocyanate (FITC)-dextran illuminate the pH changes around cells and reveal transient bright spots early in saline exposure, becoming more numerous and fixed in space with time in saline APW." Type de publication : périodique Référence biblio : Beilby M., Shepherd V., Absolonova M., 2018 - The role of H+/OH channels in saline pathology of Chara australis : brief history. Botany letters, 165 (1) : 45-54. Permalink : http://www.cbnbrest.fr/catalogue_en_ligne/index.php?lvl=notice_display&id=67205
in Botany letters > vol. 165, n°1 (Année 2018) . - pp. 45-54[article]Exemplaires(1)
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Titre : Towards an integrated understanding of charophyte biology and paleobiology Type de document : texte imprimé Auteurs : Mary Beilby, Auteur ; S. Schneider, Auteur ; Andrzej Puckacz, Auteur ; Carles Martin-Closas, Auteur Année de publication : 2018 Article en page(s) : pp. 7-10 Langues : Anglais (eng) Mots-clés : charophyte  molecular genetics  physiology  ecology  paleobotany Résumé : "In this special issue, we present an overview of the presentations given at the 7th Meeting of the International Research Group on charophytes held in Astana in 2016. Charophytes, understood as the members of extant Charales and their direct ancestors (fossil orders Sycidiales and Moellerinales), represent a significant plant group that provides an iconic research system for many diverse fields, such as evolution, ecology, electrophysiology, phytoremediation and management of wetlands. Charophytes have been proposed as one of the closest ancestors of land plants. Their fossil record goes back to 425 Ma (million years ago), but the rise of the oldest living charophyte genera is dated from ca 155–125 Ma. An example of vegetations already dominated by early Characeae has been recently found in China, dating back to that time. The definition of charophyte species has been a matter of debate, since the morphology of these plants shows a great plasticity. The elucidation of charophyte taxonomy is of major importance for the definition of endangered species. New light is shed by the use of genetic coding for the distinction of problematic species within the Chara genus. Climate change is one of the major concerns in the present scenario of disturbance of charophyte habitats. Specific adaptations, including changes in thallus morphology, parthenogenesis and enhanced production of oospores, develop when charophyte habitats become unstable, desiccate or increase their salinity. Brackish charophytes are also a subject of special attention, since they include species highly specialized in particular niches and highly vulnerable to extreme salinities reached through habitat desiccation. The chemistry of water controls the distribution of species, even at the biogeographic scale. Experiments, related to the transport of ions across the charophyte cell membrane, provide an understanding of how charophytes adapt physiologically to those changes." Type de publication : périodique Référence biblio : Beilby M., Schneider S., Puckacz A., Martin-Closas C., 2018 - Towards an integrated understanding of charophyte biology and paleobiology. Botany letters, 165 (1) : 7-10. Permalink : http://www.cbnbrest.fr/catalogue_en_ligne/index.php?lvl=notice_display&id=67139
in Botany letters > vol. 165, n°1 (Année 2018) . - pp. 7-10[article]Exemplaires(1)
Cote Localisation Disponibilité P0177-6 Brest Exclu du prêt
