scholarly journals Regulation of Intracellular pH in Sea Urchin Eggs by Medium Containing Both Weak Acid and Base.

1997 ◽  
Vol 22 (4) ◽  
pp. 387-398 ◽  
Author(s):  
Miyako S. Hamaguchi ◽  
Kenji Watanabe ◽  
Yukihisa Hamaguchi
Nature ◽  
1976 ◽  
Vol 262 (5570) ◽  
pp. 661-664 ◽  
Author(s):  
James D. Johnson ◽  
David Epel ◽  
Miles Paul

Author(s):  
Isabelle Galgani ◽  
Danielle Pesando ◽  
Jacqueline Porthe-Nibelle ◽  
Barthélémy Fossat ◽  
Jean-Pierre Girard

1983 ◽  
Vol 100 (1) ◽  
pp. 29-38 ◽  
Author(s):  
Patrick Payan ◽  
Jean-Pierre Girard ◽  
Brigitte Ciapa

1981 ◽  
Vol 89 (2) ◽  
pp. 284-291 ◽  
Author(s):  
C H Johnson ◽  
D Epel

Intracellular pH (pH1) of sea urchin eggs and embryos was determined using DMO (5,5-dimethyl-2,4-oxazolidinedione). By this method, the pH1 of Lytechinus pictus eggs increased after fertilization from 6.86 to 7.27, and this higher pHi was maintained thereafter, as has been previously observed with pH microelectrodes. The same general result was obtained with the eggs of Strongylocentrotus purpuratus, in contrast to previous estimates of the pH of egg homogenates from this species, which had indicated a rise and then fall of pHi after fertilization. pHi did not significantly change during early cell divisions. Studies of treatments that alter pHi confirmed that ammonia alkalizes and acetate acidifies the cells. The regulation of pHi by embryos in the acidic seawater is impaired if sodium is absent, whereas unfertilized eggs can regulate pHi in acidic, sodium-free seawater.


1980 ◽  
Vol 105 (3) ◽  
pp. 461-468 ◽  
Author(s):  
Hiroko Inoue ◽  
Tohru Yoshioka

Development ◽  
1985 ◽  
Vol 89 (Supplement) ◽  
pp. 35-51
Author(s):  
Mark A. Taylor ◽  
Kenneth R. Robinson ◽  
L. Dennis Smith

The induction of amphibian oocyte maturation with progesterone as well as the activation of sea urchin eggs at the time of fertilization result in increased protein synthesis. The increase in both cases involves the recruitment of maternal mRNA onto polysomes. Further, it has been reported that sea urchin eggs, like full-grown Xenopus oocytes, contain no spare translational capacity based on the observation that injected heterologous mRNA is translated only at the expense of endogenous messages. The nature of the limiting component defined by such experiments is not known, but two factors which have been proposed to play a role in regulating protein synthesis are ribosomal protein S6 phosphorylation and intracellular pH. In the current paper, we review the literature and present new evidence on the roles intracellular pH and S6 phosphorylation have in regulating protein synthesis in Xenopus oocytes. We report that pHi does not increase between stage 3 and stage 6, yet the protein synthetic rate increases at least eight fold during the same period. Hence, we conclude that increasing pHi is not a prerequisite for increasing protein synthesis. Moreover, we present three arguments against increased ribosomal protein S6 phosphorylation being sufficient or necessary for increased protein synthesis in Xenopus oocytes. First, the level of S6 phosphorylation does not increase between stages 4 and 6, a period exhibiting a two to three fold increase in protein synthesis. Second, the injection of globin mRNA into stage-4 oocytes increases total protein synthesis two to three fold, but has no effect on S6 phosphorylation. Third, when the injection of globin mRNA into stage-4 oocytes is followed by an injection of MPF, a dramatic increase in S6 phosphorylation is seen, but total protein synthesis is not further stimulated.


1981 ◽  
Vol 22 (1) ◽  
pp. 160-164
Author(s):  
H. KIMURA ◽  
T. SHIROYA ◽  
T. AOYAMA ◽  
A. SHIMA

Nature ◽  
1977 ◽  
Vol 269 (5629) ◽  
pp. 590-592 ◽  
Author(s):  
ALINA LOPO ◽  
VICTOR D. VACQUIER

Sign in / Sign up

Export Citation Format

Share Document