[article]
| 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]
|
The role of H+/OH channels in saline pathology of Chara australis : brief history in Botany letters, vol. 165, n°1 (Année 2018)