Analysis of specific factors generating 2-cell block in AKR mouse embryos

Zygote ◽  
2006 ◽  
Vol 14 (2) ◽  
pp. 169-179 ◽  
Author(s):  
Akihiro Yoneda ◽  
Aki Okada ◽  
Teruhiko Wakayama ◽  
Junji Ueda ◽  
Tomomasa Watanabe
Keyword(s):  
Mouse Strain ◽  
Culture Medium ◽  
Mouse Strains ◽  
C57bl Mouse ◽  
Cell Block ◽  
Cell Stage ◽  
Female Progeny ◽  
Reconstructed Embryos ◽  
Specific Factors

SummaryThe phenomenon of the developmental arrest at the 2-cell stage of 1-cell embryos from some mouse strains during in vitro culture is known as the 2-cell block. We investigated the specific factors involved in the 2-cell block of AKR embryos by means of a modified culture system, the production of reconstructed embryos by pronuclear exchange and a cross experiment. In a culture medium with phosphate, 94.6% of 1-cell embryos from the C57BL mouse strain developed to the blastocyst stage, but 95.7% of embryos from the AKR mouse strain showed 2-cell block. Phosphate-free culture medium rescued the 2-cell block of AKR embryos and accelerated the first cell cycle of the embryos. Co-culture with BRL cells and a BRL-conditioned medium fractionated below 30 kDa also rescued the 2-cell block of AKR embryos. Examinations of in vitro development of reconstructed embryos and of embryos from F1 females between AKR and C57BL strains clearly demonstrated that the AKR cytoplast caused the 2-cell block. In the backcrossed female progeny between (AKR × C57BL) F1 males and AKR females, about three-quarters of the embryos were of the 2-cell blocking phenotype and about one-quarter were of the non-blocking phenotype. These results suggest that two genes are responsible for the 2-cell block of AKR embryos.

Effect of medium conditioned with rat hepatoma BRL cells on ‘2-cell block’ of random-bred mouse embryos cultured in vitro

Zygote ◽  
2009 ◽  
Vol 17 (2) ◽  
pp. 169-174 ◽  
Author(s):  
Masayuki Kobayashi ◽  
Yoshinori Terawaki ◽  
Koichi Saito ◽  
Kano Kasuga ◽  
Ikuo Kojima
Keyword(s):  
Specific Inhibitor ◽  
Reversed Phase ◽  
Mouse Embryos ◽  
Mouse Strains ◽  
Pcr Analysis ◽  
Cell Block ◽  
Cell Stage ◽  
B Subunit ◽  
Rat Hepatoma

SummaryThe phenomenon of developmental arrest at the 2-cell stage of zygotes obtained from certain mouse strains during in vitro culture is known as the 2-cell block. The effect of conditioned medium (CM) with rat hepatoma BRL cells on the 2-cell block of CD-1 mouse zygotes was investigated in comparison with that of CM with rat hepatoma Reuber H-35 cells. In control medium with EDTA, 75.4% of 2-cell embryos developed to the 4- to 8-cell stages. In the same conditions, the BRL Mr <10000 fraction inhibited the development of 2-cell embryos to the 4- to 8-cell stages (57.7%), although the inhibition by this fraction was weaker than by the Reuber Mr <10000 fraction (19.8%). As a result of reversed-phase column chromatography, a 2-cell stage specific inhibitor of the cleavage of mouse embryos (Fr.B-25), which separated into the Mr <10000 fraction of the Reuber CM, was detected at a low level in the BRL Mr <10000 fraction. On the other hand, the Mr >10000 fraction of BRL CM accelerated the development of the embryos (90.3%). This beneficial effect was also evident even in the absence of EDTA. RT-PCR analysis revealed that mRNAs encoding the β-A or β-B subunit of activins (Mr ~29000), which are well characterized cytokines that act as releasers of the 2-cell block, were expressed in BRL cells. These results indicate that BRL cells synthesize Fr.B-25 at low levels, and that activins contained in the BRL CM probably contributed to overcoming the 2-cell block of CD-1 zygotes cultured in vitro.

Alteration of extracellular cation concentrations and ratios in culture medium does not affect first cleavage division of hamster zygotes in vitro nor overcome the 'two-cell block'

1989 ◽  
Vol 1 (3) ◽  
pp. 231 ◽  
Author(s):  
BD Bavister ◽  
M Golden
Keyword(s):  
Culture Medium ◽  
Culture Media ◽  
Cell Block ◽  
Cleavage Division ◽  
Cell Stage ◽  
Wide Range ◽  
Standard Culture ◽  
Simple Medium

In vivo fertilized hamster one-cell eggs (embryos) were cultured in a simple medium that was modified to provide a wide range of concentrations and ratios of the four major cation components (sodium, potassium, calcium and magnesium) while maintaining total osmotic pressure at 290 +/- 5 mosm. Embryos were cultured in these media to find the optimum cation concentrations for supporting the first cleavage division in vitro and to determine if physiologically abnormal cation concentrations and/or ratios in standard culture media could account for the 'two-cell block' to development in vitro in this species. Despite using a broad range of ratios for sodium:potassium (from 45:1 to 5:1) and for calcium:magnesium (from 17:1 to 1:1), there were no significant differences in the proportions of fertilized eggs that underwent the first cleavage division (approx. 60-80% across all treatments), and none of the two-cell embryos underwent further cleavage during extended culture. These data demonstrate that the first cleavage division of hamster embryos in vitro is insensitive to extracellular concentrations and ratios of the major cations, and that the non-physiological concentrations and/or ratios of these cations in the culture medium are not the primary reason for the failure of hamster zygotes to develop past the two-cell stage in vitro.

scholarly journals Immunologic properties of bacterial lipopolysaccharide (LPS). II. The unresponsiveness of C3H/HeJ Mouse spleen cells to LPS-induced mitogenesis is dependent on the method used to extract LPS.

1975 ◽  
Vol 142 (6) ◽  
pp. 1488-1508 ◽  
Author(s):  
B J Skidmore ◽  
D C Morrison ◽  
J M Chiller ◽  
W O Weigle
Keyword(s):  
B Cells ◽  
Mouse Strain ◽  
Structural Integrity ◽  
Mitogenic Activity ◽  
Bacterial Lipopolysaccharide ◽  
Mouse Strains ◽  
Striking Difference ◽  
Spleen Cells ◽  
Destructive Effect

The C3H/HeJ mouse strain, previously shown to be a nonresponder to bacterial lipopolysaccharide (LPS)-induced mitogenesis in vitro, was demonstrated by the present studies to be competent to respond mitogenically to LPS, but only to LPS preparations obtained by selected extraction methods. These preparations appear to be confined to LPS isolated by mild extraction techniques, such as TCA or butanol. In contrast, those obtained by techniques utilizing phenol were only weakly stimulatory or completely nonstimulatory for spleen cells from the C3H/HeJ. All LPS preparations tested, on the other hand, were highly stimulatory for cells from another mouse strain, namely the C3H/St. The critical importance of the method of extraction of LPS on its mitogenic activity for C3H/HeJ cells was stressed by experiments in which LPS was prepared from Escherichia coli K235 using either of two procedures. In these experiments, phenol-extracted LPS, although mitogenic in the C3H/St, was completely nonstimulatory in the C3H/HeJ; whereas, butanol-extracted LPS was highly stimulatory in both strains of mice. This striking difference was attributed to a destructive effect of phenol on LPS, as demonstrated by the fact that treatment of butanol LPS with phenol resulted in a total loss of its mitogenic activity in the C3H/HeJ, but in only a partial loss in the C3H/St. In general, the mitogenic response observed with selected LPS preparations in the C3H/HeJ was quantitatively lower and more transient than that seen with the C3H/St, although qualitatively these responses appeared to be similar. This was evidenced by the observation that in both mouse strains LPS was a specific mitogen for B cells, a property which was also attributed in both strains to the same distinct structural region of the LPS molecule, that is lipid A. A preparation of LPS that failed to stimulate B cells from the C3H/HeJ nonetheless had the capacity to block activation of these B cells by a stimulatory preparation of LPS. These results strongly suggest that mitogenic stimulation of B cells by LPS is a function of the structural integrity of both the LPS molecule and putative B-cell receptors for LPS.

27 CLONING OF ADULT PIGS USING SCRIPTAID TREATMENT AND PREOVULATORY EMBRYO TRANSFER

2011 ◽  
Vol 23 (1) ◽  
pp. 120
Author(s):  
M. Albornoz ◽  
C. Colato ◽  
N. El-Beyrouthi ◽  
F. Mellano ◽  
A. Mellano ◽  
...  
Keyword(s):  
Embryo Transfer ◽  
Cell Lines ◽  
Fibroblast Cell ◽  
Cloning Efficiency ◽  
Cell Stage ◽  
Expected Time ◽  
Reconstructed Embryos ◽  
Adult Cell ◽  
Skin Biopsies

There is growing interest in the use of swine in biomedical research. Cloning from cultured somatic cells (SCNT) has been the preferred method to generate genetically modified swine models. In a recent report, swine cloning efficiency was increased by treatment of reconstructed embryos with the inhibitor of deacetylase enzymes Scriptaid (Zhao et al. 2010 Cel. Reprog. 12, 75). Also, the timing of SCNT-embryo transfer with respect to the recipient’s expected time of ovulation was shown to affect cloning efficiency, whereas preovulatory embryo transfer resulted in a higher rate of cloned piglets born compared to postovulatory embryo transfer (Petersen et al. 2008 Cloning Stem Cells 10, 355). Therefore, our objective was to combine Scriptaid treatment and preovulatory embryo transfer in the same protocol for swine cloning. Cumulus–oocyte complexes aspirated from 3- to 6-mm diameter follicles were matured in vitro under standard conditions (Martinez Diaz et al. 2010 Cel. Reprog. 12, 85) and used as host oocytes for SCNT. Fibroblast cell lines were established from skin biopsies collected from 2 adult boars and cultured in DMEM supplemented with 10% FBS and 1% antibiotics. Oocytes were micromanipulated in Tyrode’s lactate-pyruvate-HEPES medium supplemented with 7.5 μg mL–1 cytochalasin B (CB) and electrically fused using a single DC pulse of 1.6 kV cm–1 for 70 μs. Activation was performed using ionomycin (15 μM/5 min) followed by exposure to CB (7.5 μg mL–1) and cyclohexemide (10 μg mL–1) for 5 h in porcine zygote medium (PZM-3; Yoshioka et al. 2002 Biol. Reprod. 66, 112). Reconstructed embryos were exposed to 500 nM Scriptaid for 10 to 12 h starting after ionomycin treatment. Oocytes were then washed and cultured in PZM-3 medium until transfer. Peripubertal recipient gilts were synchronized by oral administration of altrenogest (Regu-Mate®; 20 mg day–1) for 12 days, followed by 1.000 IU eCG injected on the last day of altrenogest treatment and 500 IU hCG 72 h later. 1-cell stage embryos were transferred into the oviduct after ∼20 h from hCG injection or 22 h before the expected ovulation time. Pregnancy was confirmed and monitored by ultrasonography and parturition was induced by injecting PGF2α at Day 115 of pregnancy. A total of 840 reconstructed embryos were transferred into 10 gilts [average 84 (range 60–110) embryos/gilt]. 4 gilts (40%) were detected to be pregnant 4 weeks after transfer, and 2 (20%) delivered 1 (1100 g) and 2 (950 and 850 g) healthy cloned piglets. The number of embryos transferred to these 2 gilts was 85 and 70. These results confirm that Scriptaid treatment and preovulatory embryo transfer can be applied in the same cloning protocol to produce cloned piglets from adult cell lines. To our knowledge, these are the first cloned pigs produced in Latin America.

The effect of dual inhibition of Ras–MEK–ERK and GSK3β pathways on development of in vitro cultured rabbit embryos

Zygote ◽  
2020 ◽  
Vol 28 (3) ◽  
pp. 183-190 ◽  
Author(s):  
Babett Bontovics ◽  
Pouneh Maraghechi ◽  
Bence Lázár ◽  
Mahek Anand ◽  
Kinga Németh ◽  
...  
Keyword(s):  
Stem Cells ◽  
Activin A ◽  
Mouse Strains ◽  
Suitable Model ◽  
Embryonic Cells ◽  
Cell Stage ◽  
Human Ipscs ◽  
Dual Inhibition ◽  
Rabbit Embryos

SummaryDual inhibition (2i) of Ras–MEK–ERK and GSK3β pathways enables the derivation of embryo stem cells (ESCs) from refractory mouse strains and, for permissive strains, allows ESC derivation with no external protein factor stimuli involvement. In addition, blocking of ERK signalling in 8-cell-stage mouse embryos leads to ablation of GATA4/6 expression in hypoblasts, suggesting fibroblast growth factor (FGF) dependence of hypoblast formation in the mouse. In human, bovine or porcine embryos, the hypoblast remains unaffected or displays slight-to-moderate reduction in cell number. In this study, we demonstrated that segregation of the hypoblast and the epiblast in rabbit embryos is FGF independent and 2i treatment elicits only a limited reinforcement in favour of OCT4-positive epiblast populations against the GATA4-/6-positive hypoblast population. It has been previously shown that TGFβ/Activin A inhibition overcomes the pervasive differentiation and inhomogeneity of rat iPSCs, rat ESCs and human iPSCs while prompting them to acquire naïve properties. However, TGFβ/Activin A inhibition, alone or together with Rho-associated, coiled-coil containing protein kinase (ROCK) inhibition, was not compatible with the viability of rabbit embryos according to the ultrastructural analysis of preimplantation rabbit embryos by electron microscopy. In rabbit models ovulation upon mating allows the precise timing of progression of the pregnancy. It produces several embryos of the desired stage in one pregnancy and a relatively short gestation period, making the rabbit embryo a suitable model to discover the cellular functions and mechanisms of maintenance of pluripotency in embryonic cells and the embryo-derived stem cells of other mammals.

Some effects of genotype and composition of the culture medium on the development of mouse zygotes in vitro

1993 ◽  
Vol 5 (4) ◽  
pp. 405 ◽  
Author(s):  
ZF Du ◽  
RG Wales
Keyword(s):  
Culture Medium ◽  
Blastocyst Stage ◽  
Blastocyst Development ◽  
Cell Stage ◽  
Reciprocal Crosses ◽  
Maternal Genome ◽  
Zygote Development ◽  
Mouse Zygotes ◽  
Better Than

The effects of EDTA and the presence of glucose and glutamine in CZB medium on the development of mouse zygotes of different genotype were investigated. Although 30-80% of zygotes (depending on the cross) passed the 2-cell stage in EDTA-free medium, the addition of a low concentration of EDTA was necessary in these experiments to obtain blastocysts in culture. In reciprocal crosses between outbred (Qs), inbred (DBA/2) and hybrid (B10D2F1) stock, there was evidence of a strong influence of the maternal genome on zygote development, with those from B10D2F1 females performing best irrespective of sire. A paternal influence on development was also evident but the most successful sire varied with the genotype of female used and reciprocal crosses differed greatly in the ability of the resultant zygote to develop in culture. For zygotes recovered from Qs females, CZB medium containing glucose and glutamine supported development to the blastocyst stage better than did medium devoid of these substrates. Tests with embryos from B10D2F1 females indicated that the presence of glucose for the whole or for part of the incubation period stimulated blastocyst development. However, the addition of glutamine to the medium in these tests had no significant effect on the development of blastocysts.

The microenvironment created by non-blocking embryos in aggregates may rescue blocking embryos via cell–embryo adherent contacts

Zygote ◽  
1995 ◽  
Vol 3 (4) ◽  
pp. 313-324 ◽  
Author(s):  
Galina G. Sekirina ◽  
Irina E. Neganova
Keyword(s):  
Culture Medium ◽  
Inbred Mouse ◽  
Inbred Mouse Strain ◽  
Culture Conditions ◽  
Adherent Cell ◽  
Cell Block ◽  
Block Medium ◽  
Cell Stage ◽  
Rescue Effect ◽  
Cell Embryo

SummaryUnder our culture conditions, mouse embryos from the BALB/c inbred mouse strain develop successfully in culture only from the late 2-cell stage onwards (so-called 2-cell block), whether or not EDTA is added to the culture medium. (CBA × C57BL) F2 embryos do not exhibit a 2-cell block. Medium conditioned by culture of non-blocking embryos from the 2-cell to the 8-cell stage did not improve the development of blocking embryos, nor did co-culture of blocking and non-blocking embryos, with or without conditioned medium. On the other hand phytohaemagglutinin (PHA)-assisted aggregation of an early 2-cell BALB/c embryo with five surrounding non-blocking F2 embryos (2-cell or 8-cell) or five BALB/c 8-cell embryos allowed the early 2-cell BALB/c embryos to develop into blastocysts within 72 h. Aggregation of blocking BALB/c 2-cell embryos with each other had no ‘rescue’ effect. When blocking and non-blocking 2-cell embryos were aggregated together, an integrated blastocyst was formed; but when the early 2-cell BALB/c embryos were aggregated with non-blocking 8-cell embryos, the blocking embryos formed a separate small blastocyst, which nonetheless retained adherent contact with the non-blocking embryos throughout the culture period. Ultrastructural analysis showed that 2-cell embryos aggregated with the aid of PHA form close adherent cell contacts up to several micrometres in length.

scholarly journals Leptin has concentration and stage-dependent effects on embryonic development in vitro

Reproduction ◽  
2006 ◽  
Vol 132 (2) ◽  
pp. 247-256 ◽  
Author(s):  
Muren Herrid ◽  
Van Ly Nguyen ◽  
Geoff Hinch ◽  
James R McFarlane
Keyword(s):  
Embryonic Development ◽  
Embryo Development ◽  
Culture Medium ◽  
Leptin Receptor ◽  
Inhibitory Effect ◽  
Differential Sensitivity ◽  
Cell Stage ◽  
Paracrine Signalling ◽  
Stage Of Development

There is accumulating evidence that leptin may be directly involved in pre-implantation embryonic development, however, it is unclear whether there is a concentration and stage-dependent regulatory pattern. In this study, the addition of 10 ng/ml human recombinant leptin to the culture medium significantly increased the percentage of two-cell mouse embryos that developed into blastocysts and hatched blastocysts, whereas in the presence of 100 ng/ml leptin, the development rate was significantly inhibited. The total cell numbers in the hatched blastocysts were significantly higher in the presence of 10 ng/ml leptin compared with controls and higher concentrations. The differential sensitivity to leptin was found to vary among embryos at different stages of development. Supplementation of leptin (10 ng/ml) to culture medium at two- to eight-cell stages resulted in a consistent stimulatory effect on embryo development. Most interestingly, the inhibitory effect of high leptin concentration (100 ng/ml) on embryo development was diminished when it was added to the culture medium at the eight-cell stage of development. The concentration-dependent regulation pattern was confirmed using sheep embryos, under similar conditions although sheep embryos appeared to be more sensitive in responding to leptin. Having established the effect of exogenous leptin on embryo development, the expression pattern of leptin and its receptors were also investigated. Leptin mRNA was not detected in mouse two-, four-, eight-cell and blastocyst stage embryos, whereas three isoforms of leptin receptor (Ob-Ra, Ob-Rb and Ob-Re) were identified in these cells, indicating that leptin is likely to modulate embryo development via a paracrine signalling system.

285 THE EFFICIENCY OF INTRACYTOPLASMIC SPERM INJECTION v. LASER-ASSISTED IN VITRO FERTILIZATION WITH FROZEN SPERM FOR RECOVERY TRANSGENIC C57BL/6 MOUSE STRAINS

2011 ◽  
Vol 23 (1) ◽  
pp. 240
Author(s):  
A. C. Carstea ◽  
Z. Polgar ◽  
L. Kovacs ◽  
A. Dinnyes
Keyword(s):  
In Vitro Fertilization ◽  
Intracytoplasmic Sperm Injection ◽  
Skim Milk ◽  
Mouse Strains ◽  
Chi Square ◽  
Cell Stage ◽  
Important Indicator ◽  
Vitro Fertilization ◽  
Cryopreserved Sperm

The progress of molecular genetics generated thousands of new transgenic strains of mice which also requires their economic and safe maintenance in the form of genetic banks. Sperm freezing would be one of the easiest options; however, cryosensitivity of sperm in mice strains is prone to variation. In this study, we examined the efficiency of laser-assisted zona drilling in vitro fertilization (ZD-IVF) v. intracytoplasmic sperm injection (ICSI) for attempting to recover two transgenic (UBI-GFP/BL6 and B6;129P2- Hvcn1) and one mutant (C57BL/6J-Tyrc-2J) lines. The sperm was frozen with 18% raffinose and 3% skim milk (Nakagata 2000 Mamm Genome 11, 572–576). Data of the replicates was analysed by chi-square method. The motility rates after thawing of cryopreserved sperm were 10% for UBI-GFP/BL6, 30% C57BL/6J-Tyrc-2J and 50% for B6;129P2-Hvcn1 strains. Regular IVF attempts in the UBI-GFP/BL6 and the mutant strain resulted in very few embryos and no pups (data not shown). Following ZD-IVF, the 2-cell stage rates were 7/60 (12%) for UBI-GFP/BL6, 18/60 (30%) for C57BL/6J-Tyrc-2J, and 34/60 (56%) for B6;129P2- Hvcn1. After ICSI, 66–74% of the oocytes survived the procedure and their development to 2-cells stage were 12/20 (60%) (UBI-GFP/BL6), 25/39 (64%) (C57BL/6J-Tyrc-2J) and 26/37 (70%) (B6;129P2-Hvcn1). The number of 2-cell stage embryos produced by ICSI was significantly (P < 0.05) increased compared with those produced following ZD-IVF in case of UBI-GFP/BL6 and C57BL/6J-Tyrc-2J strains. The 2-cell stage embryos were transferred into recipients and the newborn rates from ZD-IVF v. ICSI embryos were 0% v. 17% (UBI-GFP/BL6), 28% v. 36% (C57BL/6J-Tyrc-2J) and 12% v. 12% (B6;129P2- Hvcn1), respectively; none of them were significantly different. In conclusion, when using cryopreserved sperm, the post-thaw motility is an important indicator for the selection of the rederivation method of cryopreserved transgenic mouse strains; while ZD-IVF, an easier method to perform, is suitable for the higher motility samples, ICSI could be strongly recommended for those showing low motility. This work was financed by EU FP6: CLONET (MRTN-CT-2006-035468), TEAMOHOLIC (MEXT-CT-2003-509582); EU FP7: RESOLVE (FP7-HEALTH-F4-2008-202047), RabPStem (PERG07-GA-2010-268422), and NKFP_07_1-ES2HEART-HU (OM-00202-2007).

scholarly journals Ultrastructural changes in goat interspecies and intraspecies reconstructed early embryos

Zygote ◽  
2008 ◽  
Vol 16 (2) ◽  
pp. 93-110 ◽  
Author(s):  
Yong Tao ◽  
Lizi Cheng ◽  
Meiling Zhang ◽  
Bin Li ◽  
Jianping Ding ◽  
...  
Keyword(s):  
Nuclear Envelope ◽  
Developmental Change ◽  
Early Stage ◽  
Ultrastructural Changes ◽  
Cell Stage ◽  
Developmental Potential ◽  
Reconstructed Embryos ◽  
Low Efficiency

SummaryThe low efficiency of somatic cell nuclear transfer may be related to the ultrastructural deviations of reconstructed embryos. The present study investigated ultrastructural differences between in vivo-produced and cloned goat embryos, including intra- and interspecies embryos. Goat ear fibroblast cells were used as donors, while the enucleated bovine and goat oocytes matured in vitro as recipients. Goat–goat (GG), goat–cattle (GC) and goat in vivo-produced embryos at the 2-cell, 4-cell, 8-cell and 16-cell stages were compared using transmission electron microscopy. These results showed that the three types of embryos had a similar tendency for mitochondrial change. Nevertheless, changes in GG embryos were more similar to changes in in vivo-produced embryos than were GC embryos, which had more extreme mitochondrial deviation. The results indicate the effects of the cytoplast on mitochondria development. The zona pellucida (ZP) in all three types of embryos became thinner and ZP pores in both GC and GG embryos showed an increased rate of development, especially for GC embryos, while in vivo-produced embryos had smooth ZP. The Golgi apparatus (Gi) and rough endoplasmic reticulum (RER) of the two reconstructed embryos became apparent at the 8-cell stage, as was found for in vivo embryos. The results showed that the excretion of reconstructed embryos was activated on time. Lipid droplets (LD) of GC and GG embryos became bigger, and congregated. In in vivo-produced embryos LD changed little in volume and dispersed gradually from the 4-cell period. The nucleolus of GC and GG embryos changed from electron dense to a fibrillo-granular meshwork at the 16-cell stage, showing that nucleus function in the reconstructed embryos was activated. The broken nuclear envelope and multiple nucleoli in one blastomere illuminated that the nucleus function of reconstructed embryos was partly changed. In addition, at a later stage in GC embryos the nuclear envelope displayed infoldings and the chromatin was concentrated, implying that the blastomeres had an obvious trend towards apoptosis. The gap junctions of the three types of embryos changed differently and GG and GC embryos had bigger perivitelline and intercellular spaces than did in vivo-produced embryos. These results are indicative of normal intercellular communication at an early stage, but this became weaker in later stages in reconstructed embryos. In conclusion, inter- and intraspecies reconstructed embryos have a similar pattern of developmental change to that of in vivo-produced embryos for ZP, rough ER, Gi and nucleolus, but differ for mitochondria, LD, vesicles, nucleus and gap junction development. In particular, the interspecies cloned embryos showed more severe destruction. These ultrastructural deviations might contribute to the compromised developmental potential of reconstructed embryos.

Sign in / Sign up

Export Citation Format

Share Document