scholarly journals Variations in the microstructure of histones during early cleavage stages in Echinus

1968 ◽  
Vol 109 (3) ◽  
pp. 24P-24P ◽  
Author(s):  
M G Ord ◽  
L A Stocken
Keyword(s):  
Early Cleavage ◽  
Cleavage Stages

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.

Incorporation of Uridine in Cleavage Stage Eggs of the Sea Urchin Paracentrotus Lividus

1971 ◽  
Vol 26 (8) ◽  
pp. 816-821 ◽  
Author(s):  
Larry E. Bockstahler
Keyword(s):  
Ion Exchange ◽  
Sea Urchin ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Paracentrotus Lividus ◽  
Cleavage Stage ◽  
Early Cleavage ◽  
Cell Stage ◽  
Cleavage Stages ◽  
Layer Chromatography

Incorporation of uridine in cleavage stage eggs of the sea urchin Paracentrotus lividus was investigated. It was shown by ion exchange and thin layer chromatography that most of the uridine taken up during the 16-cell stage was converted into UTP with some incorporation into UDP and UMP. Conversion of uridine to these phosphorylated nucleosides occurred throughout early cleavage stages. A very small amount of uridine taken up by cleavage stage eggs is incorporated into RNA heterogeneous in size. This RNA was examined by polyacrylamide gel electrophoresis.

X-ray Inactivation of Nuclei as a Method for Studying their Function in the Early Development of Fishes

Development ◽  
1959 ◽  
Vol 7 (2) ◽  
pp. 173-192
Author(s):  
A. A. Neyfakh
Keyword(s):  
Ionizing Radiation ◽  
Early Development ◽  
Nuclear Region ◽  
Blastula Stage ◽  
Early Cleavage ◽  
X Ray ◽  
Male Nucleus ◽  
Cleavage Stages ◽  
Heavy Dose

It is generally accepted at present that during cleavage in echinoderms, amphibians, and fishes, the nuclei do not have specific functions in regulating development, their role being at this time restricted to participation in the processes of cleavage (Schechtman & Nishihara, 1955). Eggs devoid of nuclei sometimes begin cleavage which may proceed up to the stage of the late blastula. Extirpation or inactivation of nuclei may be achieved through the separation of the nuclear region of the egg by means of centrifugation (Harvey, 1940); through extirpation of the female nucleus followed by fertilization with sperm inactivated by a heavy dose of radiation (Briggs, Green, & King, 1951); through spontaneous degeneration of the male nucleus during artificial androgenesis (Stauffer, 1945); and by means of other techniques. Exposure of early cleavage stages in amphibians (Mangold & Peters, 1956; Sanides, 1956) and fishes (Neyfakh, 1956a) to heavy doses of ionizing radiation also leads to arrest of development at the late blastula stage.

73 APPLICATION OF THE HOLLOW FIBER VITRIFICATION METHOD TO THE CRYOPRESERVATION OF HIGHLY CRYOSENSITIVE EMBRYOS

2015 ◽  
Vol 27 (1) ◽  
pp. 129 ◽  
Author(s):  
A. Uchikura ◽  
H. Matsunari ◽  
K. Nakano ◽  
S. Hatae ◽  
Y. Matsumura ◽  
...  
Keyword(s):  
Early Stage ◽  
Hollow Fibre ◽  
Membrane Thickness ◽  
Early Cleavage ◽  
Diverse Species ◽  
Organ Regeneration ◽  
Cleavage Stages ◽  
Vitro Development ◽  
Technological Options

We recently demonstrated that the hollow fibre vitrification (HFV) method (Matsunari et al. 2012) could effectively be applied to the cryopreservation of embryos from diverse species. In this study, we applied the HFV method to the cryopreservation of highly cryosensitive specimens, such as in vitro matured (IVM)/IVF-derived porcine zona-free morulae and blastomeres isolated from those morulae, as well as IVM/IVF-derived cattle embryos at early cleavage stages. Porcine parthenogenetic morulae (d-4) derived from IVM oocytes were treated with 0.25% pronase to remove zona pellucidae. The resulting blastomeres were isolated from the zona-free morulae by a decompaction treatment followed by gentle pipetting. Bovine IVM-IVF embryos at the 2 to 4 cell (d-1), 8 to 16 cell (d-3), and morula stages (d-5) were then subjected to vitrification. The HFV procedure was performed as described previously using 15% dimethyl sulfoxide, 15% ethylene glycol, and 0.5 M trehalose as cryoprotectants. Four to twenty embryos, or all of the blastomeres isolated from a single morula, were individually loaded into a cellulose acetate hollow fibre (25 mm long, 185 μm φ, 15 μm membrane thickness) and vitrified. Survival of the vitrified embryos was assessed by in vitro development to blastocysts. Blastomeres recovered after vitrification were aggregated in micro-wells to examine their ability to form blastocysts. The HFV method was demonstrated to be effective for cryopreserving zona-free in vitro-produced porcine morulae and the blastomeres isolated from them (Table 1), as well as bovine IVM-IVF embryos at early cleavage stages. These data demonstrate that the HFV method is effective for highly cryosensitive specimens, such as IVM/IVF-derived porcine zona-free morulae and blastomeres isolated from those morulae, and IVM/IVF-derived cattle embryos at early cleavage stages. These achievements may expand the technological options in the production of cloned and genetically modified pigs that are useful for biomedical research. Table 1.Survival of zona-free porcine morulae and isolated blastomeres after vitrification (top) and blastocyst formation rates in bovine early-stage in vitro matured-IVF embryos after vitrification (bottom) This study was supported by JST, ERATO, the Nakauchi Stem Cell and Organ Regeneration Project, and MUIIBR.

Bruno-like protein is localized to zebrafish germ plasm during the early cleavage stages

2006 ◽  
Vol 6 (2) ◽  
pp. 201-205 ◽  
Author(s):  
Yoshiko Hashimoto ◽  
Hitoshi Suzuki ◽  
Yuji Kageyama ◽  
Kunio Yasuda ◽  
Kunio Inoue
Keyword(s):  
Germ Plasm ◽  
Early Cleavage ◽  
Cleavage Stages

Ultrastructural development of merosporangia in the mycoparasite Piptocephalis indica

1979 ◽  
Vol 57 (21) ◽  
pp. 2460-2465 ◽  
Author(s):  
Karen K. Baker
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Wall Layer ◽  
Outer Electron ◽  
Early Cleavage ◽  
Single Row ◽  
Transparent Wall ◽  
Cleavage Stages ◽  
Scanning Electron

Transmission and scanning electron microscopy were used to study the ultrastructural development of merosporangia of Piptocephalis indica. Merosporangial branches were initiated from heart-shaped basal-spore initials on dichotomously branched sporangiophores. After elongation, spores were cleaved out of the merosporangial protoplast by simultaneous invagination of the plasmalemma. The plasmalemmal invaginations fused at the center of the merosporangium and delimited a varying number of more or less equal-sized spores in a single row. At maturity. spores had an inner, electron-transparent wall layer and an outer, electron-opaque wall layer. Mature spores possessed scars at each end with the basal spore having scars at each point of merosporangial disarticulation. Fertile branches were highly vacuolated at the time of spore detachment. Development of merosporangiospores in P. indica is similar to that in Syncephalis sphaerica at the early cleavage stages with some differences evident at postcleavage.

DNS-Synthese in frühen Furchungsstadien von Seeigelembryonen / DNA-Synthesis in Early Cleavage Stages of Sea Urchin Embryos

1970 ◽  
Vol 25 (9) ◽  
pp. 1047-1052 ◽  
Author(s):  
G. Czihak ◽  
E. Pohl
Keyword(s):  
Dna Synthesis ◽  
Sea Urchin ◽  
Incubation Time ◽  
Transport Mechanism ◽  
Nuclear Dna ◽  
Incorporation Rate ◽  
Thymidine Uptake ◽  
Early Cleavage ◽  
Single Nucleus ◽  
Cleavage Stages

Incorporation rate of thymidine into nuclear DNA of cleaving sea urchin eggs is independent of the incubation time before fertilization. The incorporation rate into the single nucleus was found to be higher in later cleavage stages than immediately after fertilization. A constant value is reached after a certain time. Thymidine uptake is considered to be dependent on a transport mechanism starting with fertilization.

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