893 Ko
Sardet, C., et al. (1989). Development 105, 237-249
Roegiers F.,et al. (1999) Development, 126, 3101-3117
Cortical and Cytoplasmic Reorganisations
in Ascidian Eggs
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893 Ko
|
Meiotic contractions,
Vegetal button formation ,Second Major Phase of Ooplasmic Segregation mitosis
and cleavage; this sequence is speeded up 100
times and corresponds to the period betwwen the end of Meiosis I , the meeting
of male and female Pronuclei, Mitosis, and first Cleavage, lasting from
10 minutes to 50 minutes after fertilization(Phallusia mammillata). Sardet, C., et al. (1989). Development 105, 237-249 Roegiers F.,et al. (1999) Development, 126, 3101-3117
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511 Ko
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Cortical
ER-rich domain moves and concentrates vegetally during the first Major Phase
of Ooplasmic Segregation;
this is due to an Actomyosin-driven
contraction triggered by the fertilization calcium
wave. Here the continuous ER network in the egg is labelled with injected
DiIC(16)3 .The sequence speeded up about 10 times lasts about 5 minutes
after fertilization(Phallusia mammillata). Speksnijder J.E., et al. (1993) J. Cell Biol. 120, 1337-1346 Roegiers F.,et al. (1999) Development, 126, 3101-3117 |
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912 Ko
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Close
up of Second Phase of Ooplasmic Segregation:
30 minutes after Fertilization, the male and
female Pronuclei , Centrosomal and Mitochondria-rich Domains (Vesicular
domain on the rightof the nucleus )move together from the Posterior Cortex
(on the right) to the Egg center . The rotational movement is driven by
the o the Microtubulesin the ER-rich domain (smooth regions) with respect
to the Cortex(Phallusia mammillata). Sardet, C., et al. (1989). Development 105, 237-249 Roegiers F.,et al. (1999) Development, 126, 3101-3117 |
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266 Ko
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Mitochondria-rich
Myoplasm Domain moves Posteriorly and concentrates vegetally during the
Second Phase of Oplasmic Segregation; 25 minutes
after fertilization, at the end of meiosis II when polar bodies are
emitted , the Mitochondria-rich Myoplasm Domain labelled here with DiO(C2)3
moves to the future Posterior pole of the embryo in 2 subphases taking about
10 minutes(Phallusia mammillata) Sardet, C., et al. (1989). Development 105, 237-249 Roegiers F.,et al. (1999) Development, 126, 3101-3117 |
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522 Ko
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Fertilization,
contraction and concentration of the Mitochondria-rich Myoplasm Domain
Vegetally during the First Major Phase of Ooplasmic
Segregation: Two eggs
with their mitochondria labelled with DiO(C2)3 undergo an Actomyosin-driven
contraction cortical contraction triggered by the Fertilization Calcium
Wave and lasting 3-5 minutes. A Vegetal/contraction pole is formed which
corresponds to the future Dorsal pole of the Ascidian Embryo(Phallusia mammillata). |
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548 Ko
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Reorganisations
at the Egg surface between Meiosis I (10 minutes after Fertilization) and
first Clivage (50 minutes) : At
first the egg contracts periodically with the passage of each Meiotic Calcium
Waves, then the Vegetal Button protrudes vegetally for 10 minites. Surface
particles do not move during the second Phase of Ooplasmic Segregation but
move equatorially at the end of Mitosis (Vegetal Surface Relaxartion Wave)(Phallusia
mammillata). |