The use of sea urchin eggs as a model to investigate the effects of crassolide, a diterpene isolated from a soft coral.
Crassolide, a monocyclic diterpene isolated and purified from the soft coral Lobophytum crassum, inhibited the cell cleavage of sea urchin eggs without affecting fertilization. The effect was observed with concentrations above 2 x 10(-5)m in egg suspensions. Addition of crassolide between 5 and 40 min post-fertilization totally blocked the first cleavage, which in the control occurs 1 hr after fertilization. When added between 50 and 60 min post-fertilization, crassolide produced polynucleated cells in embryos. Crassolide did not affect the egg permeability to Na(+) and Ca(2+), but caused an increase of 0.2 units in the intracellular pH of fertilized eggs coupled with a proton efflux. Crassolide, which does not affect Ca(2+) influx or permeability at the level of storage in reticular vesicles, could be used as a negative control when analysing calcium changes in short-term toxicological studies. The relationship between the pH increase and the cell cleavage needs further investigation.
Pesando
D
D
Unité INSERM 303, BP 3, F-06230 Villefranche/Mer, France.
Graillet
C
C
Braekman
J C
JC
Dubreuil
A
A
Girard
J P
JP
Puiseux-Dao
S
S