Tolérance physiologique de l'œuf de carpe (Cyprinus carpio L.) à un choc acide appliqué au cours de l'activation, ou pendant les premières divisions de segmentation

Abstract

Summary. Physiological tolerance of carp (Cyprinus carpio L.) eggs in response to acid shock during activation or early cleavage.The tolerance of common carp eggs to a short acid shock (10-30 min) was studied by plunging the eggs in a strongly buffered acid solution during their activation or cleavage.Egg tolerance increased during activation ; its cyclic pattern then followed the rhythm of segmentation division. Egg sensitivity depended on shock duration, pH value and buffering strength of the acid solution. Egg tolerance was very high at the end of epiboly. During the first cycle of tolerance variation, an increase in shock strength (low pH) or duration caused asymmetrical widening of the cyclic sensitivity peaks.The tolerance cycle did not appear to fluctuate in all of the trials. The results have been interpreted in relation to some processes involved in egg activation (water inflow through the shell, variation in membrane permeability, calcium wave within the cytoplasm) or to the existence of an acid-sensitive phase in the blastomere cell cycle during synchronous cleavage.Introduction.

Survie embryonnaire précoce de 9 espèces de poissons d'eau douce après un choc de pH appliqué pendant la fécondation ou au cours des premiers stades du développement embryonnaire

“…La fécondation, cependant, pourrait être un moment de sensibilité critique (Roubaud et al, 1984 ;Desira et al, 1986) Ainsi avons-nous montré (Roubaud et al, 1984 ;Désira et al, 1986) Rauen, 1964) : 4-3-amino-propyl morpholine (pK, = 10,2 ; pK 2 = 6,2) ; éthylène diamine (pK, = 9,9 ; pK 2 = 6,8) ; glycine (pK = 9,6) ; tris-hydroxy-méthyl-aminométhane (pK = 8,2) ; acide acétique (pK = 4,75 (fig. 4) fig.…”