scholarly journals mir-34b/c and mir-449a/b/c are required for spermatogenesis, but not for the first cleavage division in mice

Biology Open ◽  
2015 ◽  
Vol 4 (2) ◽  
pp. 212-223 ◽  
Author(s):  
S. Yuan ◽  
C. Tang ◽  
Y. Zhang ◽  
J. Wu ◽  
J. Bao ◽  
...  
Keyword(s):  
Cleavage Division

Laser Scanning Confocal Microscopy and Three-Dimesnsional Reconstruction of the Mitotic Spindles of Unequally Dividing Embryonic Cells

1990 ◽  
Vol 48 (3) ◽  
pp. 166-167
Author(s):  
J. Holy ◽  
G. Schatten
Keyword(s):  
Confocal Microscopy ◽  
Mitotic Spindle ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Laser Scanning Confocal Microscopy ◽  
Two Dimensions ◽  
Embryonic Cells ◽  
Mitotic Spindles ◽  
Cleavage Division ◽  
Scanning Confocal Microscopy

One of the classic limitations of light microscopy has been the fact that three dimensional biological events could only be visualized in two dimensions. Recently, this shortcoming has been overcome by combining the technologies of laser scanning confocal microscopy (LSCM) and computer processing of microscopical data by volume rendering methods. We have employed these techniques to examine morphogenetic events characterizing early development of sea urchin embryos. Specifically, the fourth cleavage division was examined because it is at this point that the first morphological signs of cell differentiation appear, manifested in the production of macromeres and micromeres by unequally dividing vegetal blastomeres.The mitotic spindle within vegetal blastomeres undergoing unequal cleavage are highly polarized and develop specialized, flattened asters toward the micromere pole. In order to reconstruct the three-dimensional features of these spindles, both isolated spindles and intact, extracted embryos were fluorescently labeled with antibodies directed against either centrosomes or tubulin.

404. Repercussions of a transient decrease in pH on embryo viability and subsequent fetal development

2008 ◽  
Vol 20 (9) ◽  
pp. 84 ◽  
Author(s):  
D. L. Zander-Fox ◽  
M. Mitchell ◽  
J. G. Thompson ◽  
M. Lane
Keyword(s):  
Preimplantation Embryo ◽  
Cell Mass ◽  
Cell Number ◽  
Blastocyst Stage ◽  
High Dose ◽  
Ph Change ◽  
Fetal Outcomes ◽  
Cleavage Division ◽  
F1 Hybrid ◽  
Crown Rump Length

Changes in the environment to which the preimplantation embryo is exposed can significantly influence fetal outcomes, indicative of ‘embryo programming'. Although many previous in vitro stress models have demonstrated programming changes using high dose stress effects, it is possible to induce similar effects with a physiologically relevant stress model. This study investigates the effect of a subtle transient pH change, during the first cleavage division, on blastocyst viability and fetal outcomes after embryo transfer. Zygotes from F1 hybrid mice (C57BL6xCBA F1) were cultured to the 2-cell stage (19h) in either control G1 medium or in G1 containing a weak acid, 2 mM DMO (5,5-Dimethyl-2,4-oxazolidinedione), then cultured to the blastocyst stage in control media G1/G2 (72h). Exposure to DMO induced a decrease in intracellular pH from 7.25 (control) to 7.10 (DMO). At the blastocyst stage, inner cell mass (ICM) cell number and cellular apoptosis were assessed, or embryos were transferred to pseudopregnant recipients to assess implantation and fetal outcomes. Differences were assessed using Student's t-test or generalised linear modelling followed by post-hoc tests. Exposure to DMO during the first cleavage division significantly reduced total blastocyst cell number from 83.0 ± 6.4 to 63.6 ± 3.8 (P < 0.05), reduced ICM number from 30.6 ± 3.6 to 20.2 ± 1.8 (P < 0.05) and significantly increased the apoptotic cell index from 1.9% to 3.2% (for control verses DMO embryos respectively) (P < 0.05). Blastocyst development was unchanged. Exposure to DMO during the first cleavage division did not alter implantation rates however fetal weight was decreased from 1058.9 mg ± 25.2 (control) to 949.1 mg ± 26.7 (DMO) (P < 0.05) and crown–rump length decreased from 21.9 mm ± 0.4 (control) to 20.6 mm ± 0.5 (DMO) (P < 0.05). In conclusion, this study demonstrates that a transient reduction in pH of only 0.15 units during early preimplantation embryo development significantly reduces resultant blastocyst viability and perturbs fetal growth, indicative of altered embryo programming. The mechanism behind this permanent change however is currently unknown.

Monozygotic Twins with Discordant Sex

1992 ◽  
Vol 41 (4) ◽  
pp. 301-310 ◽  
Author(s):  
K. Kurosawa ◽  
R. Kuromaru ◽  
K. Imaizumi ◽  
Y. Nakamura ◽  
F. Ishikawa ◽  
...  
Keyword(s):  
Peripheral Blood ◽  
Skin Fibroblast ◽  
Twin Pair ◽  
Monozygotic Twins ◽  
Variable Number ◽  
Cell Populations ◽  
Normal Male ◽  
Cleavage Division ◽  
Karyotypic Analysis ◽  
Biochemical Genetic

AbstractA nine-year-old girl with short stature was referred to the department of pediatrics at Kyushu University. The clinical diagnosis was Turner syndrome; karyotypic analysis performed on peripheral blood, using GTG techniques, demonstrated a 45,X/47,XYY (17:83) mosaicism. Her twin brother, a phenotypically normal male, had the same karyotype; 45,X/47,XYY (3:97) on peripheral blood. Their skin fibroblast karyotypes showed the same mosaicism, ie. 45,X/47,XYY (41:59 and 31:69 respectively). On eleven biochemical genetic markers the twin pair were concordant, thus the likelihood of monozygosity was 0.99527034. In addition, the analysis of variable number of tandem repeat (VNTR) markers revealed the likelihood of monozygosity to be 0.99944386. The most plausible explanation of the X/XYY mosaicism was nondisjunction of the Y in the first cleavage division of the 46,XY zygote. A disproportionate rate of cell populations with 45,X and 47.XYY in the twinning process of the X/XYY embryo, especially in the germ lines, would result in discordant sex in twin pairs.

scholarly journals A FINE STRUCTURAL ANALYSIS OF CLEAVAGE INDUCTION AND FURROWING IN THE EGGS OF ARBACIA PUNCTULATA

1969 ◽  
Vol 42 (1) ◽  
pp. 170-184 ◽  
Author(s):  
Lewis G. Tilney ◽  
Douglas Marsland
Keyword(s):  
High Pressure ◽  
Fine Structure ◽  
Essential Role ◽  
Annulate Lamellae ◽  
Cleavage Division ◽  
Arbacia Punctulata ◽  
Naturally Occurring ◽  
Tentative Hypothesis ◽  
Normal Division ◽  
Experimentally Induced

A fine structural study has been carried out on the various formed elements present before, during, and after the first cleavage division, not only in normally developing Arbacia eggs, but also in eggs which have been induced to cleave prematurely by high-pressure centrifugation. The aim has been to ascertain whether or not any of the morphologically identifiable components may be involved in initiating the furrowing process. Also, attention has been given to the fine structure of the cytoplasmic cortex, particulary in the walls of the furrow, in the hope of reaching a better understanding of the mechanics of cleavage. The annulate lamellae and the membranous envelope of the nucleus are the only formed elements which disappear shortly before cleavage, not only in eggs undergoing normal division, but also in eggs which have been induced to cleave ahead of schedule by high-pressure, high-force centrifugation. Therefore, it is suggested as a tentative hypothesis that materials liberated upon disintegration of the nuclear membrane and the annulate lamellae play an essential role in initiating and effecting the furrowing reaction, especially since the stratification of these elements in experimentally induced eggs corresponds to the position of the developing furrow. Another of the membranous elements in the egg, the Golgi complex, shows considerable modification as a result of high-pressure centrifugation, but these structures do not undergo disintegration. Rather, they become curled into rounded bodies. The vacuole population is not greatly affected by inducing treatments. During cleavage, both naturally occurring and experimentally induced, a considerable number of 50 A filaments appear in the denser cytoplasmic cortex, but only in the walls of the furrow. These filaments are similar to those which have been demonstrated in a number of contractile cells. Accordingly, it is suggested that this fibrillar system may be actively involved in the development of the cleavage force.

Preimplantation mouse embryos express Mhc class I genes before the first cleavage division

1993 ◽  
Vol 38 (1) ◽  
pp. 35-40 ◽  
Author(s):  
MatthewT. Sprinks ◽  
MartinH. Sellens ◽  
GillianB. Dealtry ◽  
Nelson Fernandez
Keyword(s):  
Mhc Class I ◽  
Mouse Embryos ◽  
Class I ◽  
Cleavage Division ◽  
Preimplantation Mouse Embryos ◽  
Preimplantation Mouse

Transcription and DNA replication of sperm nuclei introduced into blastomeres of 2-cell mouse embryos

Zygote ◽  
1997 ◽  
Vol 5 (4) ◽  
pp. 289-299 ◽  
Author(s):  
Berenika Plusa ◽  
Maria A. Ciemerych ◽  
Ewa Borsuk ◽  
Andrzej K. Tarkowski
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
Mouse Embryo ◽  
Mouse Embryos ◽  
Hybrid Cells ◽  
Time Schedule ◽  
Cleavage Division ◽  
Oocyte Cytoplasm ◽  
Sperm Nuclei ◽  
Cell Mouse Embryo

SummaryThe aim of this study was to investigate the behaviour of sperm nuclei in the cytoplasm of the 2-cell mouse embryo. To this end, we produced hybrids between anucleate fertilised oocyte fragments and blastomeres of the 2-cell embryos. When sperm nuclei at the stage of decondensation or recondensation were introduced into blastomeres the development of male pronuclei was usually retarded and they never reached the size of the blastomere nuclei. These abortive male pronuclei were unable to initiate transcription but they were capable of synthesising DNA. The majority of sperm nuclei introduced into blastomeres as early male pronuclei developed normally and reached the size of the blastomere nuclei. They synthesised DNA simultaneously with blastomere nuclei and were transcriptionally active. In addition they participated in the cleavage division of hybrid cells. This shows that the very early male pronucleus when transmitted from the oocyte cytoplasm to the blastomere cytoplasm can respond positively to the new cytoplasmic factors, i.e. it undertakes both DNA replication and transcription according to the time schedule characteristic of the second cell cycle.

scholarly journals Effect of phosphate on the second cleavage division of the rat embryo

1998 ◽  
Vol 13 (2) ◽  
pp. 398-402 ◽  
Author(s):  
H. Matsumoto ◽  
S. Sugawara
Keyword(s):  
Rat Embryo ◽  
Cleavage Division
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