Reconstructed embryos derived from intersubspecies somatic cell nuclear transfer （SCNT） have poorer developmental potential than those from intrasubspecies SCNT. Based on our previous study that Holstein dairy bovi...Reconstructed embryos derived from intersubspecies somatic cell nuclear transfer （SCNT） have poorer developmental potential than those from intrasubspecies SCNT. Based on our previous study that Holstein dairy bovine （HD） mitochondrial DNA （mtDNA） haplotype compatibility between donor karyoplast and recipient cytoplast is crucial for SCNT embryo development, we performed intersubspecies SCNT using HD as donor karyoplast and Luxi yellow heifer （LY） as recipient cytoplast according to mtDNA haplotypes determined by polymerase chain reaction- restriction fragment length polymorphism （PCR-RFLP） analysis. The results demonstrated that intersubspecies mtDNA homotype SCNT embryos had higher pre- and post-implantation developmental competence than intrasubspecies mtDNA heterotype embryos as well as improved blastocyst reprogramming status, including normal H3K9 dimethylation pattern and promoter hypomethylation of pluripotent genes such as Oct4 and Sox2, suggesting that intersubspecies SCNT using LY oocytes maintains HD cloning efficiency and may reprogram HD nuclei to develop into a normal cloned animal ultimately. Our results indicated that karyoplast-cytoplast interactions and mtDNA haplotype compatibility may affect bovine intersubspecies SCNT efficiency. This study on bovine intersubspecies SCNT is valuable for understanding the mechanisms of mtDNA haplotype compatibility between karyoplast and cytoplast impacting the bovine SCNT efficiency, and provides an alternative and economic resource for HD cloning.展开更多
This study was to investigate the effects of transport, storage temperature and time on parthenogenetical developmental competence of sheep oocyte. The ovaries were collected and randomly immersed in physiological sal...This study was to investigate the effects of transport, storage temperature and time on parthenogenetical developmental competence of sheep oocyte. The ovaries were collected and randomly immersed in physiological saline at （ 10 - 15 ） ℃, （20 - 25 ） ℃ and （30 - 35 ） ℃ and transported to the laboratory for culture. They were divided into three groups randomly in an optimized transport temperature, kept in physiological saline at4 ℃, （14 -18） ℃ and （25 -30） ℃ respectively; 15 - 17 h later, the ovaries were cutured for the maturation and parthenogenetic activation of oocytes. The results showed that the optimal transport temperature of ovaries was 20 -25 ℃, when the maturation rate and blastocysts rate reached 67.44% and 35.93% respectively. Incubating sheep ovaries at （ 14 - 18 ） ℃ for （15 -17） h did not reduce the maturation rate （61.81%） and blastocysts rate （29.03%） of oocyte significantly. However, incubating sheep ovaries at 4 ℃ or （25 -30） ℃ significantly reduced the maturation rate （41.90%, 18.40% ） and cleavage rate （9.09%, 13.04% ）, and the ovaries could not develop into blastocysts at these two temperature ranges. It can be concluded that the optimal transport temperature of the sheep ovaries is 20 - 25 ℃, and incubation at 14 - 18 ℃ overnight in vivo does not affect the developmental competence of oocytes.展开更多
The photosynthetic activities between two main developmental stages, colony and hormogonium, of the edible cyanobacterium Nostoc sphaeroides Kutzing, were compared. Hormogonia have a higher content of chlorophyll than...The photosynthetic activities between two main developmental stages, colony and hormogonium, of the edible cyanobacterium Nostoc sphaeroides Kutzing, were compared. Hormogonia have a higher content of chlorophyll than that of colonies. It showed that the ratios of phycocyain （PC）, allophycocyain （APC） and phycoerythrocyanin （PEC） in hormogonia and colonies were different. The room temperature chlorophyll fluorescence, 77 K chlorophyll fluorescence, measurements of PSⅠand PS Ⅱ activities all showed that colony has higher photosynthetic competence than hormogonia. Hormogonia had a higher respiration rate than colony, while their maximum photosynthetic oxygen evolution rates were very close. The responses of hormogonia and colonies to high light illuminations also were different. Both of their oxygen evolution rates decreased quickly with the prolonged high light illumination, but hormogonia can keep relatively higher PSⅡ activity （Fv/Fm） than that of colonies. The results suggested that colony was photosynthetically more competent than hormogonia, while the ability of hormogonia to tolerate high light illumination was higher than that of colony.展开更多
Objective:To reveal the effects of 9-cis retinoic acid (RA) on cortical granules (CGs) migration andin vitro embryo production (IVP) rate in meiosisⅡvitrified bovine oocyte. Methods:Followingin vitro maturation (IVM)...Objective:To reveal the effects of 9-cis retinoic acid (RA) on cortical granules (CGs) migration andin vitro embryo production (IVP) rate in meiosisⅡvitrified bovine oocyte. Methods:Followingin vitro maturation (IVM) in a medium containing 5 nM of 9-cis-RA, 60 oocytes were vitrified and then thawed. Then, half of them were evaluated for CGs migration and the other half were used for in vitro fertilization and IVP (on day 3). In addition, the other 60 oocytes were considered as the control group, which did not receive RA in IVM medium. The data were presented to one way analysis of variance (ANOVA) and Duncan's test.Results:Results showed that IVP rate (4-8 cells embryos) was significantly (P<0.05) higher than the control group when RA had been added to IVM medium. Furthermore, the presence of RA in IVM medium improved the rate and mode of CGs migration so that the rate of oocytes that had completed CGs migration in the group, which had received RA, was significantly higher than the control group.Conclusions:This study shows that presence of RA in IVM medium enhances the developmental competence and CGs distribution of meiosisⅡvitrified bovine oocyte. Therefore, adding RA in IVM medium can decrease the ultrastructural changes during vitrification and can improve the efficiency of bovine oocyte vitrification.展开更多
基金This work was supported by the grants from the National High-Tech R&D Program of China(No.2007AA100502)the National Science and Technology Major Project of China (No.2008ZX08007-004)the National Natural Science Foundation of China(No.30770242)
文摘Reconstructed embryos derived from intersubspecies somatic cell nuclear transfer （SCNT） have poorer developmental potential than those from intrasubspecies SCNT. Based on our previous study that Holstein dairy bovine （HD） mitochondrial DNA （mtDNA） haplotype compatibility between donor karyoplast and recipient cytoplast is crucial for SCNT embryo development, we performed intersubspecies SCNT using HD as donor karyoplast and Luxi yellow heifer （LY） as recipient cytoplast according to mtDNA haplotypes determined by polymerase chain reaction- restriction fragment length polymorphism （PCR-RFLP） analysis. The results demonstrated that intersubspecies mtDNA homotype SCNT embryos had higher pre- and post-implantation developmental competence than intrasubspecies mtDNA heterotype embryos as well as improved blastocyst reprogramming status, including normal H3K9 dimethylation pattern and promoter hypomethylation of pluripotent genes such as Oct4 and Sox2, suggesting that intersubspecies SCNT using LY oocytes maintains HD cloning efficiency and may reprogram HD nuclei to develop into a normal cloned animal ultimately. Our results indicated that karyoplast-cytoplast interactions and mtDNA haplotype compatibility may affect bovine intersubspecies SCNT efficiency. This study on bovine intersubspecies SCNT is valuable for understanding the mechanisms of mtDNA haplotype compatibility between karyoplast and cytoplast impacting the bovine SCNT efficiency, and provides an alternative and economic resource for HD cloning.
基金Supported by Construction of Natural Science and Technology Platform in China(2005DKA21101)"863"Program(2006AA10Z198)Technical Development and Demonstration Program of Beijing Vocational College of Agriculture(XY-YF-14-20)
文摘This study was to investigate the effects of transport, storage temperature and time on parthenogenetical developmental competence of sheep oocyte. The ovaries were collected and randomly immersed in physiological saline at （ 10 - 15 ） ℃, （20 - 25 ） ℃ and （30 - 35 ） ℃ and transported to the laboratory for culture. They were divided into three groups randomly in an optimized transport temperature, kept in physiological saline at4 ℃, （14 -18） ℃ and （25 -30） ℃ respectively; 15 - 17 h later, the ovaries were cutured for the maturation and parthenogenetic activation of oocytes. The results showed that the optimal transport temperature of ovaries was 20 -25 ℃, when the maturation rate and blastocysts rate reached 67.44% and 35.93% respectively. Incubating sheep ovaries at （ 14 - 18 ） ℃ for （15 -17） h did not reduce the maturation rate （61.81%） and blastocysts rate （29.03%） of oocyte significantly. However, incubating sheep ovaries at 4 ℃ or （25 -30） ℃ significantly reduced the maturation rate （41.90%, 18.40% ） and cleavage rate （9.09%, 13.04% ）, and the ovaries could not develop into blastocysts at these two temperature ranges. It can be concluded that the optimal transport temperature of the sheep ovaries is 20 - 25 ℃, and incubation at 14 - 18 ℃ overnight in vivo does not affect the developmental competence of oocytes.
文摘The photosynthetic activities between two main developmental stages, colony and hormogonium, of the edible cyanobacterium Nostoc sphaeroides Kutzing, were compared. Hormogonia have a higher content of chlorophyll than that of colonies. It showed that the ratios of phycocyain （PC）, allophycocyain （APC） and phycoerythrocyanin （PEC） in hormogonia and colonies were different. The room temperature chlorophyll fluorescence, 77 K chlorophyll fluorescence, measurements of PSⅠand PS Ⅱ activities all showed that colony has higher photosynthetic competence than hormogonia. Hormogonia had a higher respiration rate than colony, while their maximum photosynthetic oxygen evolution rates were very close. The responses of hormogonia and colonies to high light illuminations also were different. Both of their oxygen evolution rates decreased quickly with the prolonged high light illumination, but hormogonia can keep relatively higher PSⅡ activity （Fv/Fm） than that of colonies. The results suggested that colony was photosynthetically more competent than hormogonia, while the ability of hormogonia to tolerate high light illumination was higher than that of colony.
文摘Objective:To reveal the effects of 9-cis retinoic acid (RA) on cortical granules (CGs) migration andin vitro embryo production (IVP) rate in meiosisⅡvitrified bovine oocyte. Methods:Followingin vitro maturation (IVM) in a medium containing 5 nM of 9-cis-RA, 60 oocytes were vitrified and then thawed. Then, half of them were evaluated for CGs migration and the other half were used for in vitro fertilization and IVP (on day 3). In addition, the other 60 oocytes were considered as the control group, which did not receive RA in IVM medium. The data were presented to one way analysis of variance (ANOVA) and Duncan's test.Results:Results showed that IVP rate (4-8 cells embryos) was significantly (P<0.05) higher than the control group when RA had been added to IVM medium. Furthermore, the presence of RA in IVM medium improved the rate and mode of CGs migration so that the rate of oocytes that had completed CGs migration in the group, which had received RA, was significantly higher than the control group.Conclusions:This study shows that presence of RA in IVM medium enhances the developmental competence and CGs distribution of meiosisⅡvitrified bovine oocyte. Therefore, adding RA in IVM medium can decrease the ultrastructural changes during vitrification and can improve the efficiency of bovine oocyte vitrification.
