Urban transport construction of thosedays should provide favourable conditionsfor cities to enter the twenty-first century.Itshould not be considered as too early to dis-cuss this issue now.What will our cities lookli...Urban transport construction of thosedays should provide favourable conditionsfor cities to enter the twenty-first century.Itshould not be considered as too early to dis-cuss this issue now.What will our cities looklike by the turn of the century Based on thestrategic goal of developing our socialisteconomy in three phases,we shall have at-tained the objectives set for the secondphase by the end of this century:our peoplewill have enjoyed fairly good living stand-展开更多
Transportation is the lifeline of human civilization and an important component of the infrastructure for economic growth.As transportation is closely related to regional economic development,the summarization of Chin...Transportation is the lifeline of human civilization and an important component of the infrastructure for economic growth.As transportation is closely related to regional economic development,the summarization of China's transportation development theory from the perspective of regional economics will be conducive to clarifying the relationships between transportation and regional economic development and providing basic theoretical support for regional economic research and policy application.From the perspective of regional economics,China’s transportation development theory falls into two categories:transportation resource allocations,and the interactions between transportation and economic development.In recent years,there has been a trend toward the integration of transportation development research with regional economic growth,and a deeper understanding of the relationships between them has been achieved.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
BELl-like transcription factors are ubiquitous in plants and interact with KNOTTEDI-types to regulate numerous developmental processes. In potato, the RNA of several BELl-like transcription factors has been identified...BELl-like transcription factors are ubiquitous in plants and interact with KNOTTEDI-types to regulate numerous developmental processes. In potato, the RNA of several BELl-like transcription factors has been identified in phloem cells. One of these, StBEL5, and its Knox protein partner regulate tuber formation by targeting genes that control growth. RNA detection methods and grafting experiments demonstrated that StBEL5 transcripts move across a graft union to localize in stolon tips, the site of tuber induction. This movement of RNA originates in source leaf veins and petioles and is induced by a short-day photoperiod, regulated by the untranslated regions, and correlated with enhanced tuber production. Addition of the StBEL5 untranslated regions to another BELl.like mRNA resulted in its preferential transport to stolon tips leading to increased tuber production. Upon fusion of the untranslated regions of StBEL5 to a β-glucuronidase marker, translation in tobacco protoplasts was repressed by those constructs containing the 3＇ untranslated sequence. The untranslated regions of the StBEL5 mRNA are involved in mediating its long-distance transport and in controlling translation. The 3＇ untranslated sequence contains an abundance of conserved motifs that may serve as binding motifs for RNA-binding proteins. Because of their presence in the phloem sieve tube system, their unique untranslated region sequences and their diverse RNA accumulation patterns, the family of BEL1-like RNAs from potato represents a valuable model for studying the long-distance transport of full-length mRNAs and their role in development.展开更多
文摘Urban transport construction of thosedays should provide favourable conditionsfor cities to enter the twenty-first century.Itshould not be considered as too early to dis-cuss this issue now.What will our cities looklike by the turn of the century Based on thestrategic goal of developing our socialisteconomy in three phases,we shall have at-tained the objectives set for the secondphase by the end of this century:our peoplewill have enjoyed fairly good living stand-
文摘Transportation is the lifeline of human civilization and an important component of the infrastructure for economic growth.As transportation is closely related to regional economic development,the summarization of China's transportation development theory from the perspective of regional economics will be conducive to clarifying the relationships between transportation and regional economic development and providing basic theoretical support for regional economic research and policy application.From the perspective of regional economics,China’s transportation development theory falls into two categories:transportation resource allocations,and the interactions between transportation and economic development.In recent years,there has been a trend toward the integration of transportation development research with regional economic growth,and a deeper understanding of the relationships between them has been achieved.
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.
基金supported by the United States Departmentof Agriculture NRI-CGP award no.2008-02806National Science Foundation-Plant Genome Research Program award no.0820659
文摘BELl-like transcription factors are ubiquitous in plants and interact with KNOTTEDI-types to regulate numerous developmental processes. In potato, the RNA of several BELl-like transcription factors has been identified in phloem cells. One of these, StBEL5, and its Knox protein partner regulate tuber formation by targeting genes that control growth. RNA detection methods and grafting experiments demonstrated that StBEL5 transcripts move across a graft union to localize in stolon tips, the site of tuber induction. This movement of RNA originates in source leaf veins and petioles and is induced by a short-day photoperiod, regulated by the untranslated regions, and correlated with enhanced tuber production. Addition of the StBEL5 untranslated regions to another BELl.like mRNA resulted in its preferential transport to stolon tips leading to increased tuber production. Upon fusion of the untranslated regions of StBEL5 to a β-glucuronidase marker, translation in tobacco protoplasts was repressed by those constructs containing the 3＇ untranslated sequence. The untranslated regions of the StBEL5 mRNA are involved in mediating its long-distance transport and in controlling translation. The 3＇ untranslated sequence contains an abundance of conserved motifs that may serve as binding motifs for RNA-binding proteins. Because of their presence in the phloem sieve tube system, their unique untranslated region sequences and their diverse RNA accumulation patterns, the family of BEL1-like RNAs from potato represents a valuable model for studying the long-distance transport of full-length mRNAs and their role in development.
