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Acid Release during Activation of Barnea candida (Mollusca, Pelecypoda) Oocytes
Author(s) -
DUBÉ FRANÇOIS,
GUERRIER PIERRE
Publication year - 1982
Publication title -
development, growth and differentiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.864
H-Index - 66
eISSN - 1440-169X
pISSN - 0012-1592
DOI - 10.1111/j.1440-169x.1982.00163.x
Subject(s) - oocyte activation , germinal vesicle , oocyte , chemistry , human fertilization , sodium , calcium , sea urchin , biophysics , biochemistry , microbiology and biotechnology , biology , embryo , anatomy , organic chemistry
Barnea caridida oocytes release acid (1.35 pmole H + /oocyte) upon fertilization. After artificial activation by an excess of KCl, germinal vesicle breakdown (GVBD) occurs normally and a quite similar, but not identical, acid release is recorded (1.10 pmole H + /oocyte). KCl activation of Barnea oocytes is completely inhibited in 100 mM sodium‐acetate sea water at pH 6.5 and fertilization does not result in activation when the oocytes are transferred after one minute into 100 mM sodium‐acetate sea water at pH 6.3. When D–600, a calcium transmembrane fluxes inhibitor, is added 20 seconds after fertilization, GVBD is inhibited but a normal acid release is recorded. The presence of at least 10 mM sodium ions in the external medium is required for 100% activation of these oocytes by an excess of KCl. These results suggest that while an intracellular pH increase may be a requisite for GVBD, this can not be a sufficient condition to trigger it unless a calcium influx is allowed to occur. Moreover, the acid release does not result from a Ca ++ ‐H + exchange transport but appears more likely to be due to a Na + ‐H * exchange as it has been demontrated in sea urchin eggs.