scholarly journals Association between p34cdc2 levels and meiotic arrest in pig oocytes during early growth

Zygote ◽  
1995 ◽  
Vol 3 (4) ◽  
pp. 325-332 ◽  
Author(s):  
Yuji Hirao ◽  
Youki Tsuji ◽  
Takashi Miyano ◽  
Akira Okano ◽  
Masashi Miyake ◽  
...  
Keyword(s):  
Germinal Vesicle ◽  
Early Growth ◽  
Catalytic Subunit ◽  
The Other ◽  
Antral Follicles ◽  
Stages Of Growth ◽  
Mean Diameter ◽  
M Phase ◽  
Chromatin Configuration ◽  
Meiotic Competence

SummaryThe molecules involved in determining meiotic competence were determined in porcine oocytes isolated from preantral and antral follicles of different sizes. Oocytes isolated from preantral follicles had a mean diameter of 78 μm, contained diffuse filamentous chromatin in the germinal vesicle and were incapable of progressing from the G2 to the M phase of the cycle even after 72 h in culture. Oocytes from early antral follicles had a mean diameter of 105 μm, showed a filamentous chromatin configuration and about half resumed meiosis but arrested at metaphase I (MI) when cultured. Oocytes from mid-antral (3–4 mm) and large antral follicles (5–6 mm) had mean oocyte diameters of 115 and 119 μm respectively, contained condensed chromatin around the nucleolus and progressed to metaphase II (MII) in 48% and 93% of instances respectively. Analysis of p34cdc2, the catalytic subunit of maturation promoting factor (MPF), by immunoblotting indicates that the inability of small (78 μm) oocytes to resume meiosis is due, at least in part, to inadequate levels of the catalytic subunit of MPF. On the other hand, the inability of intermediate-sized (105 μm) oocytes from antral follicles to complete the first meiotic division by progressing beyond MI appears not to be limited by levels of p34cdc2, which are maximal by this stage. We postulate that an inadequacy of molecules other than p34cdc2 limits progression of MI to MII; the acquisition of these molecules during the final stages of growth may be correlated with the formation of the perinucleolar chromatin rim in the germinal vesicle.

scholarly journals A prematuration approach to equine IVM: considering cumulus morphology, seasonality, follicle of origin, gap junction coupling and large-scale chromatin configuration in the germinal vesicle

2019 ◽  
Vol 31 (12) ◽  
pp. 1793 ◽  
Author(s):  
Valentina Lodde ◽  
Silvia Colleoni ◽  
Irene Tessaro ◽  
Davide Corbani ◽  
Giovanna Lazzari ◽  
...  
Keyword(s):  
Gap Junction ◽  
Embryo Development ◽  
Large Scale ◽  
Germinal Vesicle ◽  
Culture Conditions ◽  
Developmental Competence ◽  
Morphological Criteria ◽  
Chromatin Configuration ◽  
Follicle Size ◽  
Meiotic Competence

Several studies report that a two-step culture where mammalian oocytes are first kept under meiosis-arresting conditions (prematuration) followed by IVM is beneficial to embryo development. The most promising results were obtained by stratifying the oocyte population using morphological criteria and allocating them to different culture conditions to best meet their metabolic needs. In this study, horse oocytes were characterised to identify subpopulations that may benefit from prematuration. We investigated gap-junction (GJ) coupling, large-scale chromatin configuration and meiotic competence in compact and expanded cumulus–oocyte complexes (COCs) according to follicle size (<1, 1–2, >2cm) and season. Then we tested the effect of cilostamide-based prematuration in compact COCs collected from follicles <1 and 1–2cm in diameter on embryo development. Meiotic competence was not affected by prematuration, whereas COCs from follicles 1–2cm in diameter yielded embryos with a higher number of cells per blastocyst than oocytes that underwent direct IVM (P<0.01, unpaired Mann–Whitney test), suggesting improved developmental competence. Oocytes collected from follicles <1cm in diameter were not affected by prematuration. This study represents an extensive characterisation of the functional properties of immature horse oocytes and is the first report of the effects of cilostamide-based prematuration in horse oocyte IVM on embryo development.

Irrigation of kenaf (Hibiscus cannabinus L.) in the Sudan

1981 ◽  
Vol 96 (3) ◽  
pp. 569-578
Author(s):  
S. M. Farah
Keyword(s):  
Previous Experiment ◽  
Growth Period ◽  
Early Growth ◽  
Hibiscus Cannabinus ◽  
The Other ◽  
Stages Of Growth ◽  
Early Maturing ◽  
Late Stages ◽  
Infiltration Method ◽  
Late Growth

SUMMARYIn one experiment during 1972 and 1973 five irrigation regimes of every 4, 6, 8 and 10 days and according to stomatal opening, as estimated by the infiltration method, were compared, using an early-maturing variety Zankawa and a late-maturing variety G51. In both experiments early crop growth was checked by the shortest and the longest irrigation intervals.Late growth, on the other hand, was promoted by the shortest intervals in both seasons. Thus the highest yield in 1972 was obtained from the 4–day regime, followed by the infiltration method, then progressively greater yields with shorter intervals. In 1973, however, the shortest interval resulted in the lowest yield, which was significantly less than the other treatments, which showed a similar trend to those of 1972.In a second experiment during 1974 and 1975 a medium-maturing variety 22/9/1 and a late–maturing variety 44/E were added to those of the previous experiment. Watering every 4 and 6 days were eliminated and watering every 12 days added, during the early growth period. Each of these regimes was given irrigation every 6, 8, 10 and 12 days during the late growth period. The early-maturing varieties yielded best when irrigated every 12 days in the early stages, and every 10 days in the late stages, whereas the late-maturing varieties yielded best when irrigated every 10–2 and 8 days in the early and late stages of growth, respectively.

scholarly journals The position of the germinal vesicle and the chromatin organization together provide a marker of the developmental competence of mouse antral oocytes

Reproduction ◽  
2009 ◽  
Vol 138 (4) ◽  
pp. 639-643 ◽  
Author(s):  
Michele Bellone ◽  
Maurizio Zuccotti ◽  
Carlo Alberto Redi ◽  
Silvia Garagna
Keyword(s):  
Germinal Vesicle ◽  
Chromatin Organization ◽  
Developmental Competence ◽  
Cell Stage ◽  
Morphological Marker ◽  
Good Marker ◽  
Chromatin Configuration ◽  
Meiotic Competence

Based on their chromatin organization, antral oocytes can be classified into two classes, namely surrounded nucleolus (SN, chromatin forms a ring around the nucleolus), and not surrounded nucleolus (NSN, chromatin has a diffuse pattern). Oocytes of both classes are capable of meiotic resumption, but while SN oocytes, following fertilization, develop to term, NSN oocytes never develop beyond the two-cell stage. A recent study has shown that the position of the germinal vesicle (GV) can be used as a morphological marker predictive of oocyte meiotic competence, i.e. oocytes with a central GV have a higher meiotic competence than oocytes with an eccentric GV. In the present study, we have associated both markers with the aim of identifying, with more accuracy, the oocytes' developmental competence. Following their isolation, antral oocytes were classified on the basis of both SN and NSN chromatin configuration and their GV position, matured to metaphase II and fertilized in vitro. We demonstrated that the position of the GV is a good marker to predict the oocytes' developmental competence, but only when associated with the observation of the chromatin organization.

scholarly journals Bovine oocytes in secondary follicles grow and acquire meiotic competence in severe combined immunodeficient mice

Zygote ◽  
2003 ◽  
Vol 11 (2) ◽  
pp. 139-149 ◽  
Author(s):  
Shoichiro Senbon ◽  
Atsushi Ota ◽  
Masao Tachibana ◽  
Takashi Miyano
Keyword(s):  
Scid Mice ◽  
Immunoblotting Analysis ◽  
Bovine Albumin ◽  
Immunodeficient Mice ◽  
Antral Follicles ◽  
Mean Diameter ◽  
The Mean ◽  
The One ◽  
Bovine Oocytes ◽  
Meiotic Competence

Cortical tissues containing only primordial and primary follicles, or secondary follicles 140-190 μm in diameter, were collected from bovine ovaries and xenografted under the kidney capsules of female severe combined immunodeficient (SCID) mice. Histological examination revealed that all grafts were well vascularised and contained surviving follicles at 4 or 6 weeks after grafting. Primordial and primary follicles survived but did not develop beyond the one-layer stage. Secondary follicles, on the other hand, had formed antra at 4 weeks after grafting. The mean diameter of secondary follicles, which was 165.2 ± 17.0 μm (n = 42) before grafting, had developed to 442.9 ± 77.9 μm (n = 37) and 592.9 ± 116.0 μm (n = 45) in diameter at 4 and 6 weeks after grafting, respectively. The mean diameter of oocytes, which was 55.1 ± 4.9 μm (n = 42) before grafting, also increased significantly (4 weeks: 105.6 ± 6.3 μm; 6 weeks: 122.2 ± 2.6 μm; p < 0.05). Oocytes were recovered from follicles that had developed to more than 400 μm in diameter after 6 weeks, and were subjected to subsequent mature culture. Of these oocytes, 34% (11/32) resumed meiosis and 6% (2/32) matured to the second metaphase. Follicular fluid in bovine antral follicles developed in SCID mice had the 69 kDa protein, which was detected by anti-mouse albumin antibody but not by anti-bovine albumin antibody in immunoblotting analysis. These results demonstrated that bovine secondary follicles develop to the antral stage in SCID mice, and that the oocytes in the follicles acquire the meiotic competence.

scholarly journals Oocyte Meiotic Competence in the Domestic Cat Model: Novel Roles for Nuclear Proteins BRD2 and NPM1

2021 ◽  
Vol 9 ◽  
Author(s):  
Daniela R. Chavez ◽  
Pei-Chih Lee ◽  
Pierre Comizzoli
Keyword(s):  
Embryo Development ◽  
Germinal Vesicle ◽  
Domestic Cat ◽  
Nuclear Proteins ◽  
Protein Levels ◽  
Nuclear Factors ◽  
Chromatin Configuration ◽  
Mammalian Female ◽  
Adult Cat ◽  
Meiotic Competence

To participate in fertilization and embryo development, oocytes stored within the mammalian female ovary must resume meiosis as they are arrested in meiotic prophase I. This ability to resume meiosis, known as meiotic competence, requires the tight regulation of cellular metabolism and chromatin configuration. Previously, we identified nuclear proteins associated with the transition from the pre-antral to the antral follicular stage, the time at which oocytes gain meiotic competence. In this study, the objective was to specifically investigate three candidate nuclear factors: bromodomain containing protein 2 (BRD2), nucleophosmin 1 (NPM1), and asparaginase-like 1 (ASRGL1). Although these three factors have been implicated with folliculogenesis or reproductive pathologies, their requirement during oocyte maturation is unproven in any system. Experiments were conducted using different stages of oocytes isolated from adult cat ovaries. The presence of candidate factors in developing oocytes was confirmed by immunostaining. While BRD2 and ASRGL1 protein increased between pre-antral and the antral stages, changes in NPM1 protein levels between stages were not observed. Using protein inhibition experiments, we found that most BRD2 or NPM1-inhibited oocytes were incapable of participating in fertilization or embryo development. Further exploration revealed that inhibition of BRD2 and NPM-1 in cumulus-oocyte-complexes prevented oocytes from maturing to the metaphase II stage. Rather, they remained at the germinal vesicle stage or arrested shortly after meiotic resumption. We therefore have identified novel factors playing critical roles in domestic cat oocyte meiotic competence. The identification of these factors will contribute to improvement of domestic cat assisted reproduction and could serve as biomarkers of meiotically competent oocytes in other species.

Germinal vesicle chromatin configuration and meiotic competence is related to the oocyte source in canine

2008 ◽  
Vol 103 (3-4) ◽  
pp. 336-347 ◽  
Author(s):  
H.S. Lee ◽  
X.J. Yin ◽  
Y.X. Jin ◽  
N.H. Kim ◽  
S.G. Cho ◽  
...  
Keyword(s):  
Germinal Vesicle ◽  
Chromatin Configuration ◽  
Meiotic Competence

Suppression of meiosis by inhibitors of m-phase proteins in horse oocytes with low meiotic competence

Zygote ◽  
2002 ◽  
Vol 10 (1) ◽  
pp. 37-45 ◽  
Author(s):  
Katrin Hinrichs ◽  
Charles C. Love ◽  
Young Ho Choi ◽  
Dickson D. Varner ◽  
C. Nicole Wiggins ◽  
...  
Keyword(s):  
Germinal Vesicle ◽  
Condensed Chromatin ◽  
Protein Activity ◽  
Phase Protein ◽  
M Phase ◽  
Meiotic Competence

Germinal vesicle (GV)-stage horse oocytes with diffuse chromatin are meiotically incompetent and degenerate in culture, whereas horse oocytes having condensed chromatin within the GV are meiotically competent. Degeneration of incompetent oocytes in culture may be related to premature GV breakdown, which could possibly be prevented by inhibition of m-phase protein activity. We examined the effects of 6-dimethylaminopurine (6-DMAP), butyrolactone and roscovitine on GV-stage horse oocytes. Culture in the presence of 2 mM 6-DMAP for 24 h suppressed meiosis (2% MI or MII compared with 38% for untreated oocytes). The proportion of GV-stage oocytes having condensed chromatin was not different between 6-DMAP culture and directly fixed controls; however, the proportion of oocytes with diffuse chromatin was significantly lower, and more oocytes with diffuse chromatin had atypical chromatin than did controls (p < 0.01). Culture with butyrolactone at 100 mM suppressed meiosis (5% MI + II). Again, this treatment maintained GV-stage oocytes having condensed chromatin, but the proportion of oocytes with diffuse chromatin was significantly reduced compared with directly fixed controls (p < 0.05). Culture with roscovitine at 25 μM was also effective in maintaining GV-stage oocytes having condensed chromatin; however, culture with 100 μM roscovitine did not suppress meiosis or maintain oocytes in the GV stage. These results indicate that meiosis in GV-stage horse oocytes having condensed chromatin may be suppressed by inhibitors of m-phase protein activity; however, oocytes originally having diffuse chromatin appear to degenerate in culture even in the presence of these inhibitors.

Induction of DNA replication in germinal vesicles and in nuclei formed in maturing mouse oocytes by 6-DMAP treatment

Zygote ◽  
1997 ◽  
Vol 5 (3) ◽  
pp. 213-217 ◽  
Author(s):  
J. Fulka ◽  
N.L. First ◽  
C. Lee ◽  
J. Fulka ◽  
R.M. Moor
Keyword(s):  
Dna Replication ◽  
Dna Synthesis ◽  
Germinal Vesicle ◽  
The Other ◽  
Immature Oocytes ◽  
Mouse Oocytes ◽  
Germinal Vesicles ◽  
Immature Mouse ◽  
Condensed Dna ◽  
Metaphase Ii Oocytes

SummaryImmature mouse oocytes (germinal vesicle stage, GV), oocytes at different stages during maturation (prometaphase to anaphase I) and matured oocytes (metaphase II arrested) were cultured in 6-dimethylaminopurine (6-DMAP)-supplemented medium also containing bromodeoxyuridine for the assessment of DNA replication in these cells. Immature oocytes remained arrested at the GV stage and DNA replication was never detected in them. On the other hand, oocytes at the prometaphase to anaphase-telophase I stages responded to 6-DMAP treatment by forming nuclei which synthesised DNA. Mature (metaphase II) oocytes did not respond to 6-DMAP and their chromatin remained condensed. DNA synthesis could even be induced in GV-staged oocytes, but only when they were fused to freshly activated oocytes and incubated in 6-DMAP-supplemented medium.

Effects of caffeine treatment on aged porcine oocytes: parthenogenetic activation ability, chromosome condensation and development to the blastocyst stage after somatic cell nuclear transfer

Zygote ◽  
2005 ◽  
Vol 13 (4) ◽  
pp. 335-345 ◽  
Author(s):  
Masaki Iwamoto ◽  
Akira Onishi ◽  
Dai-ichiro Fuchimoto ◽  
Tamas Somfai ◽  
Shun-ichi Suzuki ◽  
...  
Keyword(s):  
Somatic Cell ◽  
Blastocyst Stage ◽  
The Other ◽  
Control Group ◽  
Blastocyst Formation ◽  
Cell Nuclei ◽  
Somatic Nucleus ◽  
Membrane Breakdown ◽  
Caffeine Treatment ◽  
M Phase

The possibility of using aged porcine oocytes treated with caffeine, which inhibits the decrease in M-phase promoting factor activity, for pig cloning was evaluated. Cumulus–oocyte complexes (COCs) were cultured initially for 36h and subsequently with or without 5mM caffeine for 24h (in total for 60h: 60CA+ or 60CA– group, respectively). As a control group, COCs were cultured for 48h without caffeine (48CA–). The pronuclear formation rates at 10h after electrical stimulation in the 60CA+ and 60CA– groups decreased significantly (p<0.05) compared with the 48CA– group. However, the fragmentation rate was significantly higher (p<0.05) in the 60CA– group than in the 60CA+ and 48CA– groups. When the stimulated oocytes were cultured for 6 days, the 60CA+ group showed significantly lower blastocyst formation and higher fragmentation or degeneration rates (p<0.05) than the 48CA– group. However, the number of total cells in blastocysts was not affected by maturation period or caffeine treatment. When somatic cell nuclei were injected into the non-enucleated oocytes and exposed to cytoplasm for a certain duration (1–11h) before the completion of maturation (48 or 60h), the rate of nuclear membrane breakdown after exposure to cytoplasm for 1–2h in the 60CA– oocytes was significantly lower (p;<0.05) than in the other experimental groups. The rate of scattered chromosome formation in the same 60CA– group tended to be lower (p=0.08) than in the other groups. After the enucleation and transfer of nuclei, blastocyst formation rates in the 60CA+ and 60CA– groups were significantly lower (p<0.05) than in the 48CA– group. Blastocyst quality did not differ among all the groups. These results suggest that chromosome decondensation of the transplanted somatic nucleus is affected by both the duration of exposure to cytoplasm and the age of the recipient porcine oocytes, and that caffeine treatment promotes nuclear remodelling but does not prevent the decrease in the developmental ability of cloned embryos caused by oocyte aging.

Sign in / Sign up

Export Citation Format

Share Document