. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 106 D. ZIVKOVIC AND M. R. DOHMEN. r300 o 200 5 £ 0) ^ a| 100 0 --100 > O -2001 ~ -40 -30 -20 Cell cycle [mm) -10 -300 100- >. (/) •o C -100- *'' '~-- ,-""" "*. d 1 -200- -300- ( p ) 20 40 60 80 100 i Cell cycle (%) 1 T P2 300- 200- < o 100- -100- • -o-200J 1-300- -400 20 40 60 Cell cycle (%) 80 100 K,t Figure 2A-C. Mean ionic current densities at the animal ( ) and the vegetal ( ) pole of Lymnuea eggs based on measurements made in copper-free tapwater (CFTW) supplemented with 2 mAI CaCli. Mean cu
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 106 D. ZIVKOVIC AND M. R. DOHMEN. r300 o 200 5 £ 0) ^ a| 100 0 --100 > O -2001 ~ -40 -30 -20 Cell cycle [mm) -10 -300 100- >. (/) •o C -100- *'' '~-- ,-""" "*. d 1 -200- -300- ( p ) 20 40 60 80 100 i Cell cycle (%) 1 T P2 300- 200- < o 100- -100- • -o-200J 1-300- -400 20 40 60 Cell cycle (%) 80 100 K,t Figure 2A-C. Mean ionic current densities at the animal ( ) and the vegetal ( ) pole of Lymnuea eggs based on measurements made in copper-free tapwater (CFTW) supplemented with 2 mAI CaCli. Mean current density during: (A) About 40 minutes preceeding the anaphase of the first meiosis (PI), 10 measurements. Current at the animal pole becomes first measurable at about 20 min prior to ana- phase of the first meiosis (PI), and remains inward during the entire period. (B) The second meiotic cell cycle, from anaphase of the first (PI) until anaphase of the second (P2) meiosis, 15 measurements. (C) The first mitotic cell cycle, from anaphase (P2| of the second meiosis until the onset of the first cleavage (Kl). 11 measurements. Maximum current densities occur during telophase (T) of the meiotic divisions. Current at the vegetal pole is outward to zero until anaphase/telophase of the first cleavage cycle (M), when it reverses to inward in most eggs. Note that the cell cycle time is expressed in percentage in Figure 2B and 2C, and in min in Figure 2A. level. This current peak was much shorter, the decrease in current more abrupt, and the minimum current den- sity lower than in an egg in the medium without diltia- zem (Fig. 3A). Perfusion with CFTW containing 5 mAI CaCl: after the decrease in current was not able to restore the current or to rescue polar body formation or cleavage. When eggs were incubated continously in CFTW con- taining from to mM diltiazem, concentration de- pendent effects were as follows from about 40 min before the first polar body formation in
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
