Full grown oocytes derived from Bufo Bufo gargarizans rearing at high temperature environment (24℃),never underwent GVBD after progesterone treatment. No p34cdc2, H1 kinase activity was detected in the oocytes after ...Full grown oocytes derived from Bufo Bufo gargarizans rearing at high temperature environment (24℃),never underwent GVBD after progesterone treatment. No p34cdc2, H1 kinase activity was detected in the oocytes after progesterone stimulation or OA microinjection; Western blotting analysis showed that the level of p3cdc2, and p33 in the oocytes are significantly lower than those in the oocytes derived from the hibernating toads (below 10 ℃). 25S-Met incorporation analysis showed that when the oocytes were incubated at 6℃, synthesis of about thirty defferent polypeptides was promoted or induced, including p34cdc2 and some other p13suc1-binding proteins. All these results indicated that a low temperature environment is essential for the oocytes of Bufo Bufo gargarizans to express and store some cell cycle drivers and its regulators, and to gain the maturation competence. These results will also provide a new clue for explaining the molecular mechanisms why gametogenesis of some organisms depends on a relative low temperature and how to maintain the geographical distribution of some animals.展开更多
Objective To establish C57BL/6J embryonic stem （ES） cell lines with potential germ- line contribution Methods ES cells were isolated from blastocyst inner cell mass of C5 7BL/6J mice, and cultured for 15 passages, a...Objective To establish C57BL/6J embryonic stem （ES） cell lines with potential germ- line contribution Methods ES cells were isolated from blastocyst inner cell mass of C5 7BL/6J mice, and cultured for 15 passages, and then injected into blastococels of ICR mice blastocysts to establish chimeric mice. Results Three ES cell lines （mC57ES1,mC57ES3, mC57ES7） derived from the inner cell mass of C57BL/6J mice blastocysts were established. They were characteristic of undifferentiated state, including normal XY karyotype, expression of a specific cell surface marker “stage-specific embryonic antigen-I” and alkaline phosphatase in continuous passage. When injected into immunodeficient mice, mC57ES1 cells consistently differentiated into derivatives of all three embryonic germ layers. When mC57ES1 cells were transferred into ICR mice blastocysts, 4 chimeric mice have been obtained. One male of them revealed successful germ-line transmission. Conclussion We have obtained C57BL/6J ES cell lines with a potential germ-line contribution, which can be used to generate transgenic and gene knock-out mice.展开更多
This paper reviewed the main components and contents of agricultural support policy system in China. By using the fundamental definition and measuring method from OECD,the research studied the relation between agricul...This paper reviewed the main components and contents of agricultural support policy system in China. By using the fundamental definition and measuring method from OECD,the research studied the relation between agricultural support level and farmers' income from 2003 to 2012. The aim of the paper is to discuss the effect of agricultural support policy on farmers' income,and provide policy suggestions for the policy makers.展开更多
p34cdc2 and Cyclin B1 are key components of cell cycle controlling machine and are believed to play a fundamental role in gametogenesis. It is also well known that, in scrotal mammals, spermatogenesis depends greatly ...p34cdc2 and Cyclin B1 are key components of cell cycle controlling machine and are believed to play a fundamental role in gametogenesis. It is also well known that, in scrotal mammals, spermatogenesis depends greatly on the maintenance of comparatively low temperature in the scrotum. To investigate whether the expression of cdc2 and Cyclin B1 in spermatogenic cells during spermatogenesis is actually a temperature dependent event, in situ hybridization, Western blotting and immunohistochemistry analysis were used to study the expression of cdc2 and Cyclin B1 in normal and cryptorchid testis. Results showed that the abdominal temperature had no significant influence on the transcription of cdc2 and Cyclin B1 in the spermatogonia and pachytene/diplotene primary spermatocytes, but it blocked the translation of them. Due to the deficiency of p34cdc2 and Cyclin B1, the spermatogonia and pachytene/diplotene primary spermatocytes were unable to form MPF, hence, they couldn’t undergo karyokinesis. The development of primary spermatocytes was arrested at the G2 to M phase transition. We also found that testosterone could regulate the Cyclin B1 expression in spermatogenic cells. Muscular injection of testosterone could recover spermatogenesis in the unilateral scrotal testis which was influenced by the contralateral cryptorchid testis, but it could not salvage the spermatogenesis block in the cryptorchid testis.展开更多
Chang’e-5 explorer successfully acquired lunar regolith core samples from depths of greater than 1 m of lunar surface.This study analyzed the lunar core drilling process based on the telemetry data,image information,...Chang’e-5 explorer successfully acquired lunar regolith core samples from depths of greater than 1 m of lunar surface.This study analyzed the lunar core drilling process based on the telemetry data,image information,and returned samples to optimize the sampling device design and enhance the understanding of the lunar regolith.In particular,a prediction method for the projected drilling path and local terrain fitting of drilling dip angle was proposed based on the flight events recorded during the core drilling process and the image information acquired before,during,and after sampling.The results revealed that the drilling dip angle of Chang’e-5 was approximately2.3.,and the deviation of the drilling length and depth was less than 2 mm.For continuous drilling,a fusion method based on telemetry data and image information was applied to determine the demarcation point of drilling with and without the lunar soil.The position of the demarcation point implied that the drilling point remained at approximately 6 mm loose soil,thereby lagging the action of the force response.Additionally,a characteristic parameter comparison method was proposed for the lunar and ground drilling to analyze the status of the lunar soil.Furthermore,the analysis results revealed that the majority of the Chang’e-5 drilling samples were derived from 0–73.8 cm below the lunar surface and few samples were extracted below 73.8 cm,as the drilling encountered several rocky regions.Moreover,the drilling point exhibited two prominent stratification variations at~28.7 cm and~70 cm below the lunar surface.Ultimately,the preliminary relationship between sample dissected position in soft tube and drilling displacement was analyzed.The segmented estimation results can support research on subsurface lunar soil.展开更多
Three organo-montmorillonites were prepared using surfactants, and their adsorption behaviors toward sulfamethoxazole（SMX） were investigated. The surfactants used were cetyltrimethyl ammonium bromide（CTMAB）, 3-（N...Three organo-montmorillonites were prepared using surfactants, and their adsorption behaviors toward sulfamethoxazole（SMX） were investigated. The surfactants used were cetyltrimethyl ammonium bromide（CTMAB）, 3-（N,N-dimethylhexadecylammonio） propane sulfonate（HDAPS） and 1,3-bis（hexadecyldimethylammonio）-propane dibromide（BHDAP）. The properties of the organo-montmorillonites were characterized by X-ray diffraction, scanning electron microscopy and N2adsorption–desorption isotherm measurements. Results showed that the interlayer spacing of montmorillonite was increased and the surface area as well as the morphology were changed. Batch adsorption experiments showed that the surfactant loading amount had a great effect on the adsorption of SMX. The adsorption process was p H dependent and the maximum adsorption capacity was obtained at p H 3 for HDAPS-Mt, while CTMAB-Mt and BHDAP-Mt showed a high removal efficiency at 3–11. The adsorption capacity increased with the initial SMX concentration and contact time but decreased with increasing solution ionic strength.Kinetic data were best described by the pseudo second-order model. Equilibrium data were best represented by the Langmuir model, and the Freundlich constant（n） indicated a favorable adsorption process. The maximum adsorption capacity of SMX was 235.29 mg/g for CTMAB-Mt, 155.28 mg/g for HDAPS-Mt and 242.72 mg/g for BHDAP-Mt. Thermodynamic parameters were calculated to evaluate the spontaneity and endothermic or exothermic nature. The adsorption mechanism was found to be dominated by electrostatic interaction,while hydrophobic interaction played a secondary role.展开更多
文摘Full grown oocytes derived from Bufo Bufo gargarizans rearing at high temperature environment (24℃),never underwent GVBD after progesterone treatment. No p34cdc2, H1 kinase activity was detected in the oocytes after progesterone stimulation or OA microinjection; Western blotting analysis showed that the level of p3cdc2, and p33 in the oocytes are significantly lower than those in the oocytes derived from the hibernating toads (below 10 ℃). 25S-Met incorporation analysis showed that when the oocytes were incubated at 6℃, synthesis of about thirty defferent polypeptides was promoted or induced, including p34cdc2 and some other p13suc1-binding proteins. All these results indicated that a low temperature environment is essential for the oocytes of Bufo Bufo gargarizans to express and store some cell cycle drivers and its regulators, and to gain the maturation competence. These results will also provide a new clue for explaining the molecular mechanisms why gametogenesis of some organisms depends on a relative low temperature and how to maintain the geographical distribution of some animals.
文摘Objective To establish C57BL/6J embryonic stem （ES） cell lines with potential germ- line contribution Methods ES cells were isolated from blastocyst inner cell mass of C5 7BL/6J mice, and cultured for 15 passages, and then injected into blastococels of ICR mice blastocysts to establish chimeric mice. Results Three ES cell lines （mC57ES1,mC57ES3, mC57ES7） derived from the inner cell mass of C57BL/6J mice blastocysts were established. They were characteristic of undifferentiated state, including normal XY karyotype, expression of a specific cell surface marker “stage-specific embryonic antigen-I” and alkaline phosphatase in continuous passage. When injected into immunodeficient mice, mC57ES1 cells consistently differentiated into derivatives of all three embryonic germ layers. When mC57ES1 cells were transferred into ICR mice blastocysts, 4 chimeric mice have been obtained. One male of them revealed successful germ-line transmission. Conclussion We have obtained C57BL/6J ES cell lines with a potential germ-line contribution, which can be used to generate transgenic and gene knock-out mice.
文摘This paper reviewed the main components and contents of agricultural support policy system in China. By using the fundamental definition and measuring method from OECD,the research studied the relation between agricultural support level and farmers' income from 2003 to 2012. The aim of the paper is to discuss the effect of agricultural support policy on farmers' income,and provide policy suggestions for the policy makers.
基金National Natural Science FOundation of China.Grant! Nos: 39770370, 39630160We are grateful to Dr. A. Koff and Dr. J. Pines f
文摘p34cdc2 and Cyclin B1 are key components of cell cycle controlling machine and are believed to play a fundamental role in gametogenesis. It is also well known that, in scrotal mammals, spermatogenesis depends greatly on the maintenance of comparatively low temperature in the scrotum. To investigate whether the expression of cdc2 and Cyclin B1 in spermatogenic cells during spermatogenesis is actually a temperature dependent event, in situ hybridization, Western blotting and immunohistochemistry analysis were used to study the expression of cdc2 and Cyclin B1 in normal and cryptorchid testis. Results showed that the abdominal temperature had no significant influence on the transcription of cdc2 and Cyclin B1 in the spermatogonia and pachytene/diplotene primary spermatocytes, but it blocked the translation of them. Due to the deficiency of p34cdc2 and Cyclin B1, the spermatogonia and pachytene/diplotene primary spermatocytes were unable to form MPF, hence, they couldn’t undergo karyokinesis. The development of primary spermatocytes was arrested at the G2 to M phase transition. We also found that testosterone could regulate the Cyclin B1 expression in spermatogenic cells. Muscular injection of testosterone could recover spermatogenesis in the unilateral scrotal testis which was influenced by the contralateral cryptorchid testis, but it could not salvage the spermatogenesis block in the cryptorchid testis.
基金supported by the National Medium and Longterm Science and Technology Major Special Project of ChinaYoung Top Talents Foundation of China Aerospace Science and Technology Corporation+1 种基金Pre-research project on Civil Aerospace Technologies by CNSA under Grant D020201the National Natural Science Foundation of China(Research on Supporting Management Strategy of Scientific Research Activities in Lunar Exploration under Grant 42142033)。
文摘Chang’e-5 explorer successfully acquired lunar regolith core samples from depths of greater than 1 m of lunar surface.This study analyzed the lunar core drilling process based on the telemetry data,image information,and returned samples to optimize the sampling device design and enhance the understanding of the lunar regolith.In particular,a prediction method for the projected drilling path and local terrain fitting of drilling dip angle was proposed based on the flight events recorded during the core drilling process and the image information acquired before,during,and after sampling.The results revealed that the drilling dip angle of Chang’e-5 was approximately2.3.,and the deviation of the drilling length and depth was less than 2 mm.For continuous drilling,a fusion method based on telemetry data and image information was applied to determine the demarcation point of drilling with and without the lunar soil.The position of the demarcation point implied that the drilling point remained at approximately 6 mm loose soil,thereby lagging the action of the force response.Additionally,a characteristic parameter comparison method was proposed for the lunar and ground drilling to analyze the status of the lunar soil.Furthermore,the analysis results revealed that the majority of the Chang’e-5 drilling samples were derived from 0–73.8 cm below the lunar surface and few samples were extracted below 73.8 cm,as the drilling encountered several rocky regions.Moreover,the drilling point exhibited two prominent stratification variations at~28.7 cm and~70 cm below the lunar surface.Ultimately,the preliminary relationship between sample dissected position in soft tube and drilling displacement was analyzed.The segmented estimation results can support research on subsurface lunar soil.
文摘Three organo-montmorillonites were prepared using surfactants, and their adsorption behaviors toward sulfamethoxazole（SMX） were investigated. The surfactants used were cetyltrimethyl ammonium bromide（CTMAB）, 3-（N,N-dimethylhexadecylammonio） propane sulfonate（HDAPS） and 1,3-bis（hexadecyldimethylammonio）-propane dibromide（BHDAP）. The properties of the organo-montmorillonites were characterized by X-ray diffraction, scanning electron microscopy and N2adsorption–desorption isotherm measurements. Results showed that the interlayer spacing of montmorillonite was increased and the surface area as well as the morphology were changed. Batch adsorption experiments showed that the surfactant loading amount had a great effect on the adsorption of SMX. The adsorption process was p H dependent and the maximum adsorption capacity was obtained at p H 3 for HDAPS-Mt, while CTMAB-Mt and BHDAP-Mt showed a high removal efficiency at 3–11. The adsorption capacity increased with the initial SMX concentration and contact time but decreased with increasing solution ionic strength.Kinetic data were best described by the pseudo second-order model. Equilibrium data were best represented by the Langmuir model, and the Freundlich constant（n） indicated a favorable adsorption process. The maximum adsorption capacity of SMX was 235.29 mg/g for CTMAB-Mt, 155.28 mg/g for HDAPS-Mt and 242.72 mg/g for BHDAP-Mt. Thermodynamic parameters were calculated to evaluate the spontaneity and endothermic or exothermic nature. The adsorption mechanism was found to be dominated by electrostatic interaction,while hydrophobic interaction played a secondary role.
