Subcellular localization of proline-rich tyrosine kinase 2 during oocyte fertilization and early-embryo development in mice

Proline-rich tyrosine kinase 2 (Pyk2), a non-receptor tyrosine kinase, is a member of the focal adhesion kinase family and is highly expressed in oocytes. Using a combination of confocal microscopy and RNAi, we localized and studied the function of both Pyk2 and tyrosine-phosphorylated Pyk2 (p-Pyk2) during mouse oocyte fertilization and early embryo development. At the onset of fertilization, Pyk2 and p-Pyk2 were detected predominantly in sperm heads and the oocyte cytoplasm. Upon formation of male and female pronuclei, Pyk2 and its activated form leave the cytoplasm and accumulate in the two pronuclei. We detected Pyk2 in blastomere nuclei and found both Pyk2 and p-Pyk2 in the pre-blastula cytoplasm. Pyk2 and its activated form then disappeared from the blastula nuclei and localized to the perinuclear regions, where blastula cells come into contact with each other. Pyk2 knockdown via microinjection of siRNA into the zygote did not inhibit early embryo development. Our results suggest that Pyk2 plays multiple functional roles in mouse oocyte fertilization as well as throughout early embryo development.

Effect of different time phases of radionuclide hepatobiliary scintigraphy on the differential diagnosis of congenital biliary atresia

To investigate the value and essentiality of 6- and 24-h delay hepatobiliary scintigraphy in the differential diagnosis of biliary atresia (BA), we retrospectively analyzed 197 infants (121 boys/76 girls; age range, 3-205 days; average age, 63.9 days) admitted to Jiangxi Children's Hospital for persistent jaundice (> 2 weeks), hepatosplenomegaly, and abnormal liver function. After receiving anti-inflammatory treatment and cholagogic pre-treatment for 7-10 days without a clear diagnosis, the children underwent 99mTc-labeled diethylacetanilide-iminodiacetic acid hepatobiliary scintigraphy. BA and infant hepatitis syndrome were diagnosed in 107 and 90 infants, respectively after laparoscopic cholangiography, surgical pathology, or 6-month clinical follow-up. The diagnostic efficiencies of hepatobiliary scintigraphy for BA were evaluated within 50 min and at 6 and 24 h. The areas under the receiver operating characteristic curves within 50 min, at 6 and 24 h were 0.696, 0.829 , and 0.779 , suggesting poor diagnostic value within 50 min, but improvement at 6 and 24 h. The compliance rate of 6- and 24-h imaging for BA diagnosis was 89.34% (176/197; paired chi-square test Kappa value, 0.77; P > 0.05), signifying high consistency. The diagnostic efficiency values of 6-/24-h imaging for BA diagnosis were sensitivity (90.65/89.72%), specificity (74.44/78.89%), accuracy (83.25/84.77%), positive and negative predictive values (80.83/83.48% and 87.01/86.59%), with no significant difference (P > 0.05). To provide optimal treatment in early BA, the- 6-h hepatobiliary scintigraphy had practical value, especially when combined with tomographic or dynamic imaging; 24-h delay imaging was deemed unnecessary because it was not significantly superior.

[Exploration of influencing factors of price of herbal based on VAR model]

Based on vector auto-regression (VAR) model, this paper takes advantage of Granger causality test, variance decomposition and impulse response analysis techniques to carry out a comprehensive study of the factors influencing the price of Chinese herbal, including herbal cultivation costs, acreage, natural disasters, the residents' needs and inflation. The study found that there is Granger causality relationship between inflation and herbal prices, cultivation costs and herbal prices. And in the total variance analysis of Chinese herbal and medicine price index, the largest contribution to it is from its own fluctuations, followed by the cultivation costs and inflation.

Effects of Aroclor 1254 on in vivo oocyte maturation in the mouse

Polychlorinated biphenyls (PCBs) are stable, lipophilic compounds that accumulate in the environment and in the food chain. Though some studies provided evidence that PCBs had adverse effects on reproductive function, most of these results were from in vitro models. Therefore we investigated the effect of Aroclor 1254 (a commercial PCBs mixture) treatments on in vivo maturation and developmental potential of mouse oocytes. In the present study, female ICR mice were treated with different doses (12.5, 25 and 50 mg/kg) of Aroclor 1254 (a commercial PCB mixture) once every 72 hours by intraperitoneal injection for 9 days. After three treatments of Aroclor 1254, the mice were superovulated to collect oocytes one day after the last exposure. The effects of Aroclor 1254 on oocyte maturation, fertilization, and preimplantation embryonic development were investigated. Immunofluorescence-stained oocytes were observed under a confocal microscope to assess the effects of Aroclor 1254 on spindle morphology. Parthenogenic activation and the incidence of cumulus apoptosis in cumulus-oocyte complexes were observed as well. Oocytes exposed to different doses of Aroclor 1254 in vivo were associated with a significant decrease in outgrowth potential, abnormal spindle configurations, and the inhibition of parthenogenetic activation of ovulated oocytes. Furthermore, the incidence of apoptosis in cumulus cells was increased after exposed to Aroclor 1254. These results may provide reference for the treatment of reproductive diseases such as infertility or miscarriage caused by environmental contaminants.

Effects of sub-chronic aluminum chloride exposure on rat ovaries

AIMS

This experiment investigated the effects of sub-chronic aluminum chloride (AlCl3) exposure on rat ovaries.

MAIN METHODS

Eighty female Wistar (5weeks old) rats, weighed 110-120g, were randomly divided into four treatment groups: control group (CG), low-dose group (LG, 64mg/kg BW AlCl3), mid-dose group (MG, 128mg/kg BW AlCl3) and high-dose group (HG, 256mg/kg BW AlCl3). The AlCl3 was administered in drinking water for 120days. The ovarian ultrastructure was observed. The activities of acid phosphatase (ACP), alkaline phosphatase (ALP), succinate dehydrogenase (SDH), Na(+)-K(+)-ATPase, Mg(2+)-ATPase and Ca(2+)-ATPase, the contents of Fe, Cu and Zn, and the protein expression of follicle-stimulating hormone receptor (FSHR) and luteinizing hormone receptor (LHR) in the ovary were determined.

KEY FINDINGS

The results showed that the structure of the ovary was disrupted, the activities of ALP, ACP, SDH, Na(+)-K(+)-ATPase, Mg(2+)-ATPase and Ca(2+)-ATPase, the contents of Zn, Fe and the protein expression of FSHR and LHR were lowered, and the content of Cu was increased in AlCl3-treated rats than those in control.

SIGNIFICANCE

The results indicate that sub-chronic AlCl3 exposure caused the damage of the ovarian structure, the disturbed metabolism of Fe, Zn and Cu and the decreased activities of Na(+)-K(+)-ATPase, Mg(2+)-ATPase and Ca(2+)-ATPase in the ovary, which could result in suppressed energy supply in the ovary. A combination of suppression of energy supply and reduction of expression of FSHR and LHR could inhibit ovulation and corpus luteum development, leading to infertility in female rats.

EPR Study of Mouse Tissues in Search for Adaptive Responses to Low Level Whole-body X-irradiation

Effect of a low dose of whole-body X-irradiation (D1 = 0.075 Gy) of mice on some biochemical changes induced in the spleen and thymus by a subsequent challenge dose (D2 = 1.5 Gy) was studied by electron paramagnetic resonance (EPR). Kunming and SHK mice were used. Concentration of ribonucleotide reductase (RR) in the spleen and thymus of unirradiated Kunming mice was 0.70 and 0.46 microM respectively, and of unirradiated SKH mice--0.37 and 0.21 microM respectively (systematic error 45%). For mice exposed only to the low dose (D1 group), a stimulating effect on RR activity in spleen and thymus was found, while in mice subjected only to the D2 dose (D2 group) activity of the enzyme in the organs decreased considerably 18 h after irradiation. The group of mice irradiated with D1 and D2 doses, given at a 6-h interval (D1 plus D2 group), showed a RR activity in the organs lower than D1 and higher than D2 groups. This finding indicates that there exists an adaptation-like response to a low-dose whole-body irradiation in murine spleen and thymus. This low 'inductive' dose makes the organs' RR less susceptible to inhibition induced by a subsequent challenge dose. Preliminary results showed that the same kind of response is probably a characteristic of the RR content of splenocytes as well as of the rate of thymidine incorporation into splenocytes. 5-Thyml radicals of DNA (TH radicals) induced in whole tissues by gamma-irradiation in vitro at 77 K were also studied. Radiochemical yield of these radicals (4.0 and 5.3 nmol j-1), for spleen and thymus respectively of unirradiated Kunming mice, and 2.3 and 2.6 nmol J-1, for spleen and thymus respectively of unirradiated SHK mice (systematic error 30%), decreased significantly in both organs upon D2 irradiation. This decrease, however, was the consequence of DNA content diminishing upon D2 irradiation rather than change of DNA radiosensitivity: the beta value of TH radicals, i.e. yield of radicals per unit mass of DNA in each organ was equal for the mice from all D1, D1 plus D2, D2 and control groups. The beta values of TH radicals in mouse spleen and thymus were of the same order of magnitude compared with the yield of the single-strand breaks of DNA measured previously in rat organs just after whole-body irradiation, i.e. about 1 x 10(2) (Gy x 10(12) Da)-1.

[Curative effect of integrative medical therapy for systematic lupus erythematosus]

OBJECTIVE

To observe the curative effect of integrative medicine for treatment of systematic lupu erythematosus (SLE).

METHODS

Totally 110 cases of SLE were randomized into two groups, 50 in the control group and 60 in the treated group, both were treated with prednisone, but to the treated group, integrative medica treatment was given additionally according to syndrome differentiation. The course for both groups was 6 months. Clinical symptoms, immunological indexes, peripheral blood figure, erythrocyte sedimentation rate (ESR), levels of C-reactive protein (CRP) and creatinine (Cr) in blood, and 24 h urinary total protein (u-TP/24 h) were observed before and after treatment.

RESULTS

Of the 60 patients in the treated group, the treatment on 29 was evaluated as clinical remission, 18 as remarkably effective, 9 as effective, and 4 as ineffective, the total effective rate being 93.33% (56/60), while that in the control group was clinical remission in 11, remarkably effective in 10, effective in 19, ineffective in 10 respectively, and the total effective rate 80% (40/50), the difference on total ef fective rate between the two groups was significant (chi2 = 4.36, P <0.05). Besides, the improvement in the treated group was superior to that in the control group in terms of clinical symptoms such as fever, arthralgia and baldness (P <0.05, P <0.01); the negative reversion rate of anti-nuclear antibody (ANA, 51.3% vs 28.1%), antidouble-stranded DNA (ds-DNA, 53.6% vs 26.1%), anti- ribonucleoprotein (RNP, 63.2% vs 29.4%) and circulating immnue complexes (CIC, 63.2% vs 29.4%, all P <0.05); lowering of immunoglobulin (for IgG, P < 0.05; IgA, P <0.01; IgM, P <0.01); as well as bettering in peripheral blood figure, ESR, CRP, Cr and u-TP/24 h (P <0.05 or P <0.01).

CONCLUSION

Integrative medical treatment is obviously effective for SLE patients.

A directional passive air sampler for monitoring polycyclic aromatic hydrocarbons (PAHs) in air mass

A passive air sampler was developed for collecting polycyclic aromatic hydrocarbons (PAHs) in air mass from various directions. The airflow velocity within the sampler was assessed for its responses to ambient wind speed and direction. The sampler was examined for trapped particles, evaluated quantitatively for influence of airflow velocity and temperature on PAH uptake, examined for PAH uptake kinetics, calibrated against active sampling, and finally tested in the field. The airflow volume passing the sampler was linearly proportional to ambient wind speed and sensitive to wind direction. The uptake rate for an individual PAH was a function of airflow velocity, temperature and the octanol-air partitioning coefficient of the PAH. For all PAHs with more than two rings, the passive sampler operated in a linear uptake phase for three weeks. Different PAH concentrations were obtained in air masses from different directions in the field test.

[Inhalation exposure assessment on gaseous PAHs in indoor air of folk houses in Beijing]

Seven gaseous polycyclic aromatic hydrocarbons (PAHs) were determined in the indoor air of 38 folk houses in Beijing during the heating and non-heating seasons, by the passive air samplers. The total average concentration of the gaseous PAHs was around 100 ng/m3, and the dominant components were those with 2 or 3 rings. The inhalation exposure of PAHs by the residents was calculated based on the concentrations of PAHs acquired, average house-staying time and respiratory rates at different ages. The calculated results indicated that, the potential total exposure rates of the seven gaseous PAHs for the adults (including senior people) during the heating and non-heating periods were 66 ng/h and 58 ng/h, respectively; while those for juvenile people were 56 ng/h and 50 ng/h, respectively.

Whole-body low dose irradiation promotes the efficacy of conventional radiotherapy for cancer and possible mechanisms

The purpose of the present study was to explore the possibility of establishing cancer radiotherapy protocols that could promote treatment efficacy at a reduced radiation dose. Mouse models of melanoma (B16) and Lewis lung carcinoma (LLC) were used in the experiments. Conventional local radiotherapy was combined with low dose whole-body irradiation (LDWBI) in the presence or absence of gene therapy by intratumor injection of a recombinant plasmid Egr-mIL-18-B7.1 (E18B). After a number of trials with different combinations it was found that a protocol of 2-week treatment with 2 x (E18B + 2 Gy + 0.075 Gy x 2) was found to be able to promote treatment efficacy at a reduced radiation dose. In this protocol local irradiation with 2Gy was administered 24h after intratumor injection of 10 microg of the plasmid E18B followed by LDWBI with 0.075 Gy every other day for 2 sessions in 1 week, and the procedure was repeated for another week. When this combined treatment was compared with conventional radiotherapy, i.e., 2Gy every other day 3 times in one week repeated for 2 weeks, the treatment efficacy was improved, as judged by increased average survival rate, reduced mean tumor weight, reduced pulmonary metastasis and suppressed intratumor capillary growth with a 2/3 reduction of radiation dose. Immunologic studies showed stimulated natural killer (NK) and cytotoxic T lymphocyte (CTL) activity as well as increased interferon-gamma (IFN-gamma) secretion in this combined treatment group as compared with the group receiving local treatment alone. It is suggested that up-regulation of host anticancer immunity by LDWBI and the initiation of expression of immune genes by both the local large dose and LDWBI are important factors in the realization of improved cancer control.

A two-compartment exposure device for foliar uptake study

An airtight two-chamber exposure devise was designed for investigating foliar uptake of polycyclic aromatic hydrocarbons (PAHs) by plants. The upper and the bottom chambers of the device were air-tightly separated by an aluminum foil and the plant aerial tissues and roots were exposed in the two chambers, respectively. The device was tested using maize exposed to several PAH species. Positive correlations between air and aerial tissue concentrations of the exposed PAH species were revealed. PAHs spiking in the culture solution had no influence on the leaf concentrations.

Different fates of donor mitochondrial DNA in bovine-rabbit and cloned bovine-rabbit reconstructed embryos during preimplantation development

The functions of mitochondria depend on precise interaction between nuclear and cytoplasmic genomes. Non-balance of mtDNA has been reported in most nuclear transfer embryos and offspring. The reason of the degradation of donor mtDNA is still not clear. To further investigate the mechanism, in this study, we designed an experiment as follows. Two fibroblast cell lines sharing same nuclear genome but different mitochondria genome backgrounds, namely cells from ear tissues of cloned bovine and its donor, were choose as donor cells and introduced into enucleated rabbit oocytes. Similar developmental potential was observed in cloned bovine-rabbit (clone group) and bovine-rabbit (non-clone group) embryos. Real-time PCR assay showed that, in non-clone group, bovine mtDNA decreased during the development of reconstructed embryo, and that a sharp decrease was detected at the blastocyst stage. In clone group, bovine mtDNA decreased slightly, and the abrupt reduction of donor mtDNA did not occur during preimplantation development. In addition, an obvious increase in rabbit mtDNA was observed in both groups at the blastocyst stage. Our results demonstrate that: 1) the fates of donor mtDNAs in bovine-rabbit and cloned bovine-rabbit reconstructed embryos were different; and 2) recipient mtDNAs replicate at blastocyst regardless of the difference of donor cells.

Dynamic changes in NuMA and microtubules in monkey-rabbit nuclear transfer embryos

Previous reports have indicated that failure in cloning monkey is attributed to the removal of nuclear mitotic apparatus (NuMA) during enucleation and subsequent abnormal organization of mitotic apparatus. This study investigated the transformation and assembly of tubulin and NuMA protein during the first cell cycle of cloned monkey embryos reconstructed by using enucleated rabbit oocytes as recipients. After the oocyte fused with a fibroblast, extensive microtubule organization was observed around the introduced nucleus in most reconstructed embryos, suggesting the introduction of a somatic cell centrosome. A high proportion of fibroblast nuclei transferred into non-activated oocytes underwent premature chromosome condensation (PCC), transient spindle organization and chromosomes separation, followed by the formation of two pronucleus-like structures. In contrast, fibroblast nuclei in pre-activated ooplasm rarely underwent PCC, but formed a swollen pronucleus-like structure. Normal spindles were observed in about one third of the cloned embryos reconstructed by both methods. After transferring monkey fibroblasts into NuMA-removed enucleated rabbit oocytes, NuMA was localized in pseudo-pronuclei and gradually moved to mitotic spindle poles at the first mitotic spindle poles. NuMA antibody microinjection resulted in spindle disorganization and chromosome misalignment, but did not significantly affect early cleavage. Our findings indicate that: 1. NuMA in donor monkey fibroblast may contribute to form a normal spindle in enucleated rabbit oocyte; 2. when non-activated cytoplasts and pre-activated cytoplasts are used as recipients, the donor nuclei undergo different morphological changes, but yield similar early embryo development; 3. although abnormal spindle organization and chromosome alignment may cause low efficiency of animal cloning, these abnormalities do not significantly affect early cleavage.

Active demethylation of individual genes in intracytoplasmic sperm injection rabbit embryos

Intracytoplasmic sperm injection (ICSI), as an assisted reproduction technique, has been widely used in animal and human. However, its possible effect on epigenetic changes has not been well studied. To investigate whether ICSI can induce aberrant DNA methylation changes in rabbit preimplantation embryos, we examined the methylation status of the SP-A promoter region and the satellite sequence Rsat IIE by bisulfite-sequencing technology. The SP-A promoter region was extensively demethylated before the first round of DNA replication commences, and the unmethylated status was maintained until morula when dynamic remethylation occurred. A similar but more moderate demethylation process was observed in satellite sequence Rsat IIE. These results are in contrast with the previous reports of no active demethylation in normal rabbit embryos, suggesting that the active demethylation we observed may be induced by ICSI.

Source diagnostics of polycyclic aromatic hydrocarbons based on species ratios: a multimedia approach

Often, the sources of polycyclic aromatic hydrocarbons (PAHs) in environmental media can be identified by comparing the ratios of concentrations of selected pairs of PAH congeners in the source emissions to the ratios in the contaminated environmental media. However, these ratios can be altered significantly due to differences in the transport of the PAH compounds in a multimedia environment. To examine such changes, a fugacity model was applied to PAH ratios in a model environment. A linear relationship between the rate of emission and the bulk media concentration was identified for each PAH compound in an environmental medium at steady state and was quantified by a receptor-to-source ratio (RRS). It was demonstrated that the RRS values of the two congeners usually differ significantly. Consequentially, PAH ratios changed remarkably from the source emissions to various environmental media. A site-specific rectification factor (RF) was defined as the ratio of the two RRS values of the paired congeners for a specific PAH ratio in a given medium, which can be applied to account for the ratio changes in a multimedia environment. The PAH ratio changes were further verified with the surface soil data collected from Tianjin, China, and the observed changes of PAH ratios were compared favorably with the model predictions. The sensitivity analysis revealed that PAH ratios of the low molecular weight compounds were less stable. The most influential parameters controlling PAH ratios were those pertaining to dry precipitation, surface-to-air diffusion, degradation in air and water, and exchange between water and sediment.

Effects of oocyte collection time and injection position on pronucleus formation and blastocyst development in round spermatid injection in mouse

The injection of spermatozoa into mouse, human and rabbit oocytes at specific times and positions can result in different rates of viable embryo development. However, it is not clear how the timing and position of round spermatid injection (ROSI) affect pronucleus (PN) formation and blastocyst development of mice. First, we determined the changes in relative position of the first polar body and the spindle, carried out ROSI from 11.5 to 13 h post-hCG administration, then activated by Sr2+, and finally compared the development of ROSI zygotes, including the formation of pronuclei and development of blastocyst. Between 11.5 and 13 h post-hCG administration, the rate of 2PN formation by ROSI at 3 o'clock was the highest among all treated oocytes. Moreover, the blastocyst rate of zygotes with two pronuclei (2PN) was up to 27.41%. These results suggest that the time and position of ROSI can significantly influence the formation of 2PN, that the rates of 2PN formation are closely correlated with blastocyst formation and that the formation of 2PN is necessary for later embryo development.

Apoptosis in rabbit embryos produced by fertilization or nuclear transfer with fibroblasts and cumulus cells

In this study, we investigated the development, the cell number of the blastocyst, and apoptosis in rabbit nuclear transfer (NT) embryos derived from adult fibroblasts and cumulus cells as compared with embryos derived fromin vivofertilization andin vitroculture. The developmental rate and the total cell number of the blastocyst were significantly lower in NT embryos than in fertilized embryos (FEs). The type of donor cells did not affect the embryonic developmental rate and the total cell number of blastocysts in NT groups. The present study investigated the onset and the frequency of apoptosis in NT embryos and FEs by using a terminal deoxynucleotidyl transferase-mediated dUTP nick and labeling (TUNEL) assay. The earliest positive TUNEL signals were detected at the eight-cell stage in NT embryos and at the morula stage in FEs. The apoptotic index of the total blastocysts, the inner cell mass and the trophoderm was greatly higher in the NT embryos than in FEs. Moreover, the apoptotic index of the blastocyst from fibroblasts was significantly higher than that of the blastocyst from cumulus cells.

The effects of chemical enucleation combined with whole cell intracytoplasmic injection on panda-rabbit interspecies nuclear transfer

Conventional methods of somatic cell nuclear transfer either by electrofusion or direct nucleus injection have very low efficiency in animal cloning, especially interspecies cloning. To increase the efficiency of interspecies somatic cell nuclear transfer, in the present study we introduced a method of whole cell intracytoplasmic injection (WCICI) combined with chemical enucleation into panda-rabbit nuclear transfer and assessed the effects of this method on the enucleation rate of rabbit oocytes and the in vitro development and spindle structures of giant panda-rabbit reconstructed embryos. Our results demonstrated that chemical enucleation can be used in rabbit oocytes and the optimal enucleation result can be obtained. When we compared the rates of cleavage and blastocyst formation of subzonal injection (SUZI) and WCICI using chemically enucleated rabbit oocytes as cytoplasm recipients, the rates in the WCICI group were higher than those in the SUZI group, but there was no statistically siginificant difference (p > 0.05) between the two methods. The microtubule structures of rabbit oocytes enucleated by chemicals and giant panda-rabbit embryos reconstructed by WCICI combined with chemical enucleation were normal. Therefore the present study suggests that WCICI combined with chemical enucleation can provide an efficient and less labor-intensive protocol of interspecies somatic cell nuclear transfer for producing giant panda cloned embryos.

Parthenogenetic and nuclear transfer rabbit embryo development and apoptosis after activation treatments

Previous studies mainly evaluated the effect of culture conditions on preimplantation embryo apoptosis. In order to inhibit apoptosis of nuclear transfer (NT) embryos, putative apoptosis inhibitors were used to treat donor cells. However, little is known about the effect of activation treatments on embryo apoptosis. We firstly investigated the effect of various parthenogenetic activation (PA) treatments on embryo development, blastocyst cell number, and apoptosis, and then one of these activation treatments proved to be most efficient was selected for activation rabbit NT embryos. The activation by electrical pulses and 30 min later, electroporation with 25 muM D-myoinositol 1,4,5-trisphosphate (IP3) in Ca(2+)- and Mg(2+)-free PBS, then exposure to 2.0 mM 6-dimethylaminopurine (6-DMAP) for 3 hr effectively activated rabbit oocytes, and resulted in significantly a higher blastocyst development rate (72.7%) and total cell number (175 +/- 14.1), and markedly lower apoptosis level of blastocyst (4.3 +/- 0.5) than all the other groups. When the same activation protocol was applied in NT embryo activation, we found that exposure of the embryos to 6-DMAP for 3 hr could decrease the apoptosis level of blastocyst and increase blastocyst rate and cell number. The results demonstrate that oocyte activation affects not only embryo development and quality but also embryo apoptosis.

The DNA methylation events in normal and cloned rabbit embryos

To study the DNA methylation events in normal and cloned rabbit embryos, we investigated the methylation status of a satellite sequence and the promoter region of a single-copy gene using bisulfite-sequencing technology. During normal rabbit embryo development, both sequences maintained hypermethylation status until the 8- to 16-cell stage when progressive demethylation took place. In cloned embryos, the single-copy gene promoter sequence was rapidly demethylated and precociously de novo methylated, while the satellite sequence maintained the donor-type methylation status in all examined stages. Our results indicate that unique sequences as well as satellite sequences may have aberrant methylation patterns in cloned embryos.

Somatic nucleus remodelling in immature and mature Rassir oocyte cytoplasm

Successful production of cloned animals derived from somatic cells has been achieved in sheep, cattle, goats, mice, pigs, rabbits, etc. But the efficiency of nuclear transfer is very low in all species. The present study was conducted to examine somatic nucleus remodelling and developmental ability in vitro of rabbit embryos by transferring somatic cells into enucleated germinal vesicle (GV), metaphase I (MI) or metaphase II (MII) oocytes. Microtubules were organized around condensed chromosomes after the nucleus had been transferred into any of the three types of cytoplasm. A bipolar spindle was formed in enucleated MII cytoplasm. Most of the nuclei failed to form a normal spindle within GV and MI cytoplasm. Some chromosomes scattered throughout the cytoplasm and some formed a monopolar spindle. Pseudopronucleus formation was observed in all three types of cytoplasm. Reconstructed embryos with MI and MII cytoplasm could develop to blastcysts. Nuclei in GV cytoplasm could develop only to the 4-cell stage. These results suggest that (1) GV material is important for nucleus remodelling after nuclear transfer, and (2) oocyte cytoplasm has the capacity to dedifferentiate somatic cells during oocyte maturation.

The fate of mitochondria in Ibex-hirus reconstructed early embryos

Inter-species nuclear transfer could be used to preserve North Goat (Capra ibex), an endangered species. We established the culture conditions for ibex-hirus reconstructed embryos and optimized the method for DNA extractions of a single cell and early cloned embryo. By using mitochondria-specific probes of ibex and hirus respectively we found that mitochondria of donor cells can co-exist with recipients in 1-cell and 2-cell stages of the reconstructed embryos but not in the following developmental stages.

Blastocysts produced by nuclear transfer between chicken blastodermal cells and rabbit oocytes

Interspecies nuclear transfer (INT) has been used as an invaluable tool for studying nucleus-cytoplasm interactions; and it may also be a method for rescuing endangered species whose oocytes are difficult to obtain. In the present study, we investigated interaction of the chicken genome with the rabbit oocyte cytoplasm. When chicken blastodermal cells were transferred into the perivitelline space of rabbit oocytes, 79.3% of the couplets were fused and 9.7% of the fused embryos developed to the blastocyst stage. Both M199 and SOF medium were used for culturing chicken-rabbit cloned embryos; embryo development was arrested at the 8-cell stage obtained in SOF medium, while the rates of morulae and blastocysts were 12.1 and 9.7%, respectively, in M199 medium. Polymerase chain reaction (PCR) amplification of nuclear DNA and karyotype analyses confirmed that genetic material of morulae and blastocysts was derived from the chicken donor cells. Analysis mitochondrial constitution of the chicken-rabbit cloned embryos found that mitochondria, from both donor cells and enucleated oocytes, co-existed. Our results suggest that: (1) chicken genome can coordinate with rabbit oocyte cytoplasm in early embryo development; (2) there may be an 8- to 16-cell stage block for the chicken-rabbit cloned embryos when cultured in vitro; (3) mitochondrial DNA from the chicken donor cells was not eliminated until the blastocyst stage in the chicken-rabbit cloned embryos; (4) factors existing in ooplasm for somatic nucleus reprogramming may be highly conservative.