The ultrastructure of the yolk nucleus during early cleavage of Nassarius reticulatus L. (Gastropoda, Prosobranchia)

1974 ◽  
Vol 153 (1) ◽  
Author(s):  
L. Schmekel ◽  
P. Fioroni
Keyword(s):  
Early Cleavage ◽  
Nassarius Reticulatus ◽  
Yolk Nucleus

Cytological observation on fertilization and early cleavage in Sinonovaula constricta

2012 ◽  
Vol 36 (9) ◽  
pp. 1399
Author(s):  
Ying-hui DONG ◽  
Han-han YAO ◽  
Pei-yun ZHANG ◽  
Pang-you SHEN ◽  
Hao-ming LIU ◽  
...  
Keyword(s):  
Cytological Observation ◽  
Early Cleavage

Vitrification of porcine early cleavage stage embryos and oocytes after removal of cytoplasmic lipid droplets

1996 ◽  
Vol 45 (1) ◽  
pp. 180 ◽  
Author(s):  
H. Nagashima ◽  
M. Kuwayama ◽  
C.G. Grupen ◽  
R.J. Ashman ◽  
M.B. Nottle
Keyword(s):  
Lipid Droplets ◽  
Cleavage Stage ◽  
Early Cleavage ◽  
Cytoplasmic Lipid Droplets

Changes in ovarian follicle composition with plasma levels of snakes during estrus

1959 ◽  
Vol 197 (2) ◽  
pp. 360-366 ◽  
Author(s):  
Herbert C. Dessauer ◽  
Wade Fox
Keyword(s):  
Body Weight ◽  
Plasma Levels ◽  
Fat Body ◽  
Ovarian Follicle ◽  
Liver Weight ◽  
Plasma Calcium ◽  
Yolk Protein ◽  
Follicle Development ◽  
Early Cleavage ◽  
Liver Changes

The first stage of follicle development was due chiefly to hydration; during the second (deutoplasmic) stage 60 mg of solid were taken up with each 100 mg increase in follicle weight. Plasma calcium and protein P rose near end of hydration stage, remained elevated during deutoplasmic stage, reached extreme levels (max. Ca = 90 mm/l.; protein P = 86 mm/l.) near ovulation, and generally fell to anestrous levels while eggs were in early cleavage. Calcium increased in proportion to protein bound P of both plasma and follicles. During deutoplasmic stage a phospho-lipoprotein, of similar gross composition to yolk protein, appeared in plasma. Liver weight increased during hydration stage, remained elevated throughout deutoplasmic stage and decreased near ovulation. Fat body weight increased with onset of estrus, reached maximum during hydration stage and progressively decreased during deutoplasmic stage. Plasma and liver changes characteristic of estrus were reproduced in fasted male snakes with estradiol injections.

Successful cryopreservation of porcine early cleavage stage embryos following removal of cytoplasmic lipid

1995 ◽  
Vol 43 (1) ◽  
pp. 285 ◽  
Author(s):  
H. Nagashima ◽  
N. Kashiwazaki ◽  
R.J. Ashman ◽  
M.B. Nottle
Keyword(s):  
Cleavage Stage ◽  
Early Cleavage

Spatial and developmental changes in the respiratory activity of mitochondria in early Drosophila embryos

Development ◽  
1992 ◽  
Vol 115 (4) ◽  
pp. 1175-1182 ◽  
Author(s):  
T. Akiyama ◽  
M. Okada
Keyword(s):  
Respiratory Activity ◽  
Cell Formation ◽  
Rhodamine 123 ◽  
Mitochondrial Activity ◽  
Early Cleavage ◽  
Pole Cell ◽  
Posterior Group ◽  
Cleavage Stages ◽  
Pole Cells ◽  
Drosophila Embryos

Mitochondria of early Drosophila embryos were observed with a transmission electron microscope and a fluorescent microscope after vital staining with rhodamine 123, which accumulates only in active mitochondria. Rhodamine 123 accumulated particularly in the posterior pole region in early cleavage embryos, whereas the spatial distribution of mitochondria in an embryo was uniform throughout cleavage stages. In late cleavage stages, the dye showed very weak and uniform accumulation in all regions of periplasm. Polar plasm, sequestered in pole cells, restored the ability to accumulate the dye. Therefore, it is concluded that the respiratory activity of mitochondria is higher in the polar plasm than in the other regions of periplasm in early embryos, and this changes during development. The temporal changes in rhodamine 123-staining of polar plasm were not affected by u.v. irradiation at the posterior of early cleavage embryos at a sufficient dosage to prevent pole cell formation. This suggests that the inhibition of pole cell formation by u.v. irradiation is not due to the inactivation of the respiratory activities of mitochondria. In addition, we found that the anterior of Bicaudal-D mutant embryos at cleavage stage was stained with rhodamine 123 with the same intensity as the posterior of wild-type embryos. No pole cells form in the anterior of Bic-D embryos, where no restoration of mitochondrial activity occurs in the blastoderm stage. The posterior group mutations that we tested (staufen, oskar, tudor, nanos) and the terminal mutation (torso) did not alter staining pattern of the posterior with rhodamine 123.

Memoirs: On the Early Stages in the Development of Flustrella hispida (Fabricius), and on the Existence of a "Yolk Nucleus" in the Egg of this Form

1906 ◽  
Vol s2-50 (199) ◽  
pp. 435-478
Author(s):  
R. M. PACE
Keyword(s):  
Cell Lineage ◽  
Cell Stage ◽  
Single Row ◽  
Early Stages ◽  
Yolk Nucleus ◽  
Foregoing Paper

The main points in the foregoing paper maybe summarised as follows : (1) A "yolk nucleus" of the type described by Bambeke, as occurring in the egg of Pholcus, is present in the developing egg of Flustrella hispida. (2) Segmentation and cell-lineage have been followed out in detail up to the 32-cell stage. (3) The formation of the endoderm has been traced. (4) The oral and aboral ectoderm are differentiated as early as the 16-cell stage, and remain quite distinct from that time onwards. (5) The ciliated ring of the larva is formed by the coalescence of several originally distinct rows of cells, and not by the hypertrophy of a single row. (6) A stomach, comparable to that of Alcyonidium, is present also in Flustrella.

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