Le prochain séminaire du département AVIV « Adaptations du vivant » du Muséum national d’histoire naturelle se tiendra :
Jeudi 12 juillet 2018 à 12h30 au MNHN, bâtiment de la Baleine, amphithéâtre Rouelle
Et accueillera :
Dr Pung-Pung Hwang, Institute of Cellular and Organismic Biology, Academia Sinica, Nankang, Taipei, Taiwan
Titre du séminaire : "Evolutionary physiology of fish acid-base regulation"
Stenohaline zebrafish expresses both H+-ATPase (HA) and Na+/H+ exchanger (NHE3) in the apical membrane of gill (or skin) acid-secreting ionocytes, and HA is the major player. The trait of HA as the major acid-secreting transporter appears to be conserved in limited fish species. Euryhaline medaka, similar to most of fish species, adopted NHE as the major acid-secreting transporter (the trait of NHE). NHE-mediated NH4+ excretion also plays a substantial role in the net acid excretion. The relative role of NH4+ excretion in the net acid excretion predominates over that of titratable acid (mainly, H+) in fish, and the difference between H+ secretion and NH4+ excretion is increasing following fish evolution. Mammalian kidney appears to present all these traits.
Invité par Sylvie Dufour, UMR BOREA, Dpt Aviv