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1.
The objective of the present study was to establish a method for nuclear replacement in metaphase‐II (M‐II) stage porcine oocytes. Karyoplasts containing M‐II chromosomes (K) and cytoplasts without chromosomes (C) were produced from in vitro‐matured oocytes by a serial centrifugation method. The oocytes were then reconstructed by fusion of one karyoplast with 1, 2, 3 or 4 cytoplasts (K + 1C, K + 2C, K + 3C and K + 4C, respectively). Reconstructed oocytes, karyoplasts without fusion of any cytoplast (K) and zona‐free M‐II oocytes (control) were used for experiments. The rates of female pronucleus formation after parthenogenetic activation in all groups of reconstructed oocytes (58.2–77.4%) were not different from those of the K and control groups (58.2% and 66.0%, respectively). In vitro fertilization was carried out to assay the fertilization ability and subsequent embryonic development of the reconstructed oocytes. The cytoplast : karyoplast ratio did not affect the fertilization status (penetration and male pronuclear formation rates) of the oocytes. A significantly high monospermy rate was found in K oocytes (p < 0.05, 61.6%) compared with the other groups (18.2–32.8%). Blastocyst formation rates increased significantly as the number of the cytoplasts fused with karyoplasts increased (p < 0.05, 0.0–15.3%). The blastocyst rate in the K + 4C group (15.3%) was comparable with that of the control (17.8%). Total cell numbers in both the K + 3C and K + 4C groups (16.0 and 15.3 cells, respectively) were comparable with that of the control (26.2 cells). Our results demonstrate that a serial centrifugation and fusion (Centri‐Fusion) is an effective method for producing M‐II chromosome transferred oocytes with normal fertilization ability and in vitro development. It is suggested that the number of cytoplasts fused with a karyoplast plays a critical role in embryonic development.  相似文献   
2.
The conventional anatomical study of specimens requires cutting processes which destruct the limited specimens. A non-destructive method, namely an ultrasonography, can be used to assess the anatomical organ information of those specimens. The aim of this research is to analyse the macroanatomy of the female reproductive organ in the Sunda porcupine (Hystrix javanica), using ultrasonographical imaging. In this study, four formaldehyde-fixed reproductive organ specimens of the Sunda porcupine were used. A 10–12 MHz linear ultrasound transducer was utilized to provide an imaging format of both longitudinal and transversal views. Photographic images were then used as comparison with a sonographic image. The results show that the ultrasound image of the Sunda porcupine reproductive organ soft tissue was hypoechoic, the lumen and antrum follicles were anechoic, while atretic follicles and the mons pubis were hyperechoic. Generally, the size of the organ was not significantly different between photographical and ultrasonographical imaging (p > .05). In conclusion, ultrasound images can be utilized for anatomical studies of the Sunda porcupine reproductive organs without destructing the specimen.  相似文献   
3.
Fluorescence expression by bovine embryos was examined after pronuclear microinjection with an enhanced green fluorescent protein (EGFP) cDNA under control of the chicken beta-actin promoter and cytomegalovirus enhancer, as a first step in evaluating the applicability of EGFP for non-invasive selection of transgenic bovine embryos. After injection, developmental competence of the embryos was reduced, and light was emitted in 11.9% of them (37/310) under a fluorescence microscope. Although 2.9% of the injected embryos developed to the fluorescent blastocysts (9/310), a majority of the fluorescent embryos showed mosaic expression including the negative blastomeres (26/37, 70.3%). These results suggest the feasibility of EGFP for in vitro selection of transgenic bovine embryos by fluorescence microscopy. However, the impaired development and high frequency of mosaicism were observed in these injected embryos.  相似文献   
4.
The ultimate goal of this study was to establish an in vitro system to produce sperms. To pursue this goal, immature porcine testicular cells were cultured in stereostructural form and cultured testicular cord was investigated morphologically. At 4 weeks of age, the seminiferous tubules of the porcine testes consisted of undifferentiated germ cells (gonocytes and undifferentiated spermatogonia) and immature Sertoli cells. The interstitial tissue was largely occupied by Leydig cells. The testes were enzymatically digested, and the dispersed cells were encapsulated with alginate either immediately or after freeze-thawing. The resulting testicular cell cords were cultured for up to 10 weeks. After 2 weeks of culture, Sertoli cells, which were identified by their inhibin-positive reaction in immunohistochemistry, and Leydig cells, which were identified by their morphological characteristics, were observed in the cords. Neither undifferentiated nor differentiated types of germ cells were detected. The number of cells in the cords progressively decreased during the culture period. In order to discover the fate of the Sertoli cells, the level of inhibin in the spent media was determined. Inhibin in the media was at a detectable level after 2 days of culture. The levels increased and peaked at 2 weeks. When frozen-thawed testicular cells were applied to the culture, the peak level was maintained for over 8 weeks, in contrast to the gradual decrease of inhibin level when fresh cells were cultured. These results indicate that the culture conditions can sustain the survival of Sertoli cells. Further improvement is required for proliferation and differentiation of germ cells.  相似文献   
5.
The crude testicular cells (CTCs) contain many cell types, such as Sertoli cells, leydig cells, spermatogonial stem cells (SSCs), spermatocytes, and other somatic testicular cells, that secrete various growth factors needed in spermatogenesis. The objective of this study was to characterize development of 5‐day‐old mice testicular cells cultured. Crude testicular cells prepared from the testes of 5‐day‐old male mice were cultured in Dulbecco's Modified Eagle Medium and incubated at 37°C in a 5% CO2 atmosphere for 6 days. The results demonstrated that the testicular cells developed rapidly with a population doubling time (PDT) of 0.63 days and more than 90% of cells were viable after being cultured for 3 days. The number of Sertoli‐like cells increased significantly over days 1, 3, and 6 to 22.1%, 34.6%, and 50.1%, respectively. A significant increase was also observed in fibroblast‐like cells (15.5% on day 1 to 28.8% on day 3 and to 26.6% on day 6). In contrast, the number of spermatogonia‐like cells decreased significantly (54.3%, 30.4%, and 18.7%, on days 1, 3, and 6, respectively). These data indicated that the developmental pattern of the testicular cell in this study might be affected by the niche provided by the cultured testicular cells.  相似文献   
6.
This study was conducted to improve parthenogenetic development in vitro of feline oocytes following a combined activation treatment of electrical stimulation and cycloheximide. In vitro matured (IVM) oocytes were stimulated electrically by a DC electrical pulse of 2 kV/cm for 50 micros. The stimulated oocytes were then incubated in MK-1 medium with or without cycloheximide and subsequently cultured in vitro for 6 days. No significant differences were observed between the two groups with respect to the proportions of cleavage, development to the morula stage, and the cell number of blastocysts. However, exposure of electrically stimulated oocytes to cycloheximide significantly increased the rate of development of the stimulated oocytes into the blastocyst stage compared with oocytes stimulated by electrical stimulation alone (31.0% vs 6.7%). The results from the present study suggested that a single electrical stimulation was insufficient to activate the IVM cat oocytes at 24 h of maturation and that exposure to cycloheximide following electrical stimulation improved the efficacy of the parthenogenetic development of domestic cat oocytes.  相似文献   
7.
The ability of frozen-thawed fetal skin was examined to generate viable cell lines for nuclear transfer. Fetal skin frozen at -35 degrees C or -80 degrees C in the presence of 5% DMSO were used as tissue explants to generate somatic cells. The resultant confluent cells were then used as donors for nuclear transfer (NT). Of the bovine NT embryos reconstructed from the somatic cells, 78% to 81% showed cleavage, 43% to 48% reached the stage of morula formation and 34% to 35% reached blastocyst formation. There were no significant differences in development (P>0.05) when the NT embryos were compared with those reconstructed from fresh somatic-cell-derived skin tissues (75%, 45%, and 38%, for cleavage, and development to morula and blastocyst stages, respectively). The results indicated that cell lines derived from bovine fetal skin cryopreserved by a simple method could be used as donors in nuclear transfer. The resulting embryos showed similar development in vitro to those reconstructed from unfrozen fetal-skin-derived somatic cells.  相似文献   
8.
BackgroundConditioned medium is the medium obtained from certain cultured cells and contained secretome from the cells. The secretome, which can be in the form of growth factors, cytokines, exosomes, or other proteins secreted by the cells, can induce the differentiation of cells that still have pluripotent or multipotent properties.ObjectivesThis study examined the effects of conditioned medium derived from E17 rat brain cells on cells with pluripotent properties.MethodsThe conditioned medium used in this study originated from E17 rat brain cells. The CM was used to induce the differentiation of primary colonies of mice blastocysts. Primary colonies were stained with alkaline phosphatase to analyze the pluripotency. The morphological changes in the colonies were examined, and the colonies were stained with GFAP and Neu-N markers on days two and seven after adding the conditioned medium.ResultsThe conditioned medium could differentiate the primary colony, beginning with the formation of embryoid-body-like structure; round GFAP positive cells were identified. Finally, neuron-like cells testing positive for Neu-N were observed on the seventh day after adding the conditioned medium.ConclusionsConditioned medium from different species, in this case, E17 rat brain cells, induced and promoted the differentiation of the primary colony from mice blastocysts into neuron-like cells. The addition of CM mediated neurite growth in the differentiation process.  相似文献   
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