开花时间对植物的繁殖成功至关重要。广泛分布的物种经常发生开花时间的分化,从而能够更好地适应不同的环境条件。为了探索植物开花行为发生适应性分化的分子机制,首先要明确调控开花行为的遗传通路。本文梳理了植物各类群调控开花时间...开花时间对植物的繁殖成功至关重要。广泛分布的物种经常发生开花时间的分化,从而能够更好地适应不同的环境条件。为了探索植物开花行为发生适应性分化的分子机制,首先要明确调控开花行为的遗传通路。本文梳理了植物各类群调控开花时间的遗传通路,以期为开花时间适应性分化的分子机制研究提供依据。植物从营养生长向繁殖转变时,其开花行为主要受到光照、温度、水分等外界环境因子和赤霉素等内在因素的影响。通过对模式植物拟南芥(Arabidopsis thaliana)和其他类群的研究,总结出了调控植物开花时间的6条通路,包括日照长度和光质影响开花的光依赖通路,长时间冷暴露后促进植物开花的春化通路,高温或低温环境影响开花的温度通路,以及赤霉素通路、年龄通路和自主通路3条内部调节过程。植物开花时间调控的6条上游通路信号传递到下游的开花整合基因FT(FLOWERING LOCUS T)和SOC1(SUPPRESSOR OF OVER-EXPRESSION OF CONSTANS 1),整合基因将这些复杂的调节因子整合后进一步传递到下游花分生组织,从而启动开花。此外,非编码RNA、转座子对开花时间的调控也具有重要作用。部分遗传通路被证实在植物适应环境的过程中起到了重要作用。目前对植物开花调控的研究已经有一百多年历史,理论相对成熟。然而,仍然存在许多具有争议和未解决的问题,如开花基因的表达方式、开花行为的特殊调控机制、开花时间变异的适应性意义等等,需要更进一步的研究。展开更多
脊椎动物的Dmrt(double-sex and mab-3related transcription factor)是指与果蝇Dsx基因和线虫Mab-3基因同源的基因家族。本文阐述了Dmrt家族中8个成员的基因和蛋白结构特征,并通过分析Dmrt在各类脊椎动物发育中的表达显示,Dmrt家族主...脊椎动物的Dmrt(double-sex and mab-3related transcription factor)是指与果蝇Dsx基因和线虫Mab-3基因同源的基因家族。本文阐述了Dmrt家族中8个成员的基因和蛋白结构特征,并通过分析Dmrt在各类脊椎动物发育中的表达显示,Dmrt家族主要参与性别决定和性腺分化,也参与某些非性腺组织器官的发育:Dmrt1主要参与精巢分化,也与卵巢发育有关;Dmrt2主要参与体节的发生、分化以及非对称器官的形成;Dmrt3,4,5可共同参与或依次调控嗅器和脑的发育;Dmrt7为雄性配子发生所必须;Dmrt8属雄性偏向表达基因。Dmrt1在各脊椎动物的遗传性别决定通路中的位置和作用位点不同。展开更多
Mobile robot global path planning in a static environment is an important problem. The paper proposes a method of global path planning based on neural network and genetic algorithm. We constructed the neural network m...Mobile robot global path planning in a static environment is an important problem. The paper proposes a method of global path planning based on neural network and genetic algorithm. We constructed the neural network model of environmental information in the workspace for a robot and used this model to establish the relationship between a collision avoidance path and the output of the model. Then the two-dimensional coding for the path via-points was converted to one-dimensional one and the fitness of both the collision avoidance path and the shortest distance are integrated into a fitness function. The simulation results showed that the proposed method is correct and effective.展开更多
Embryonic stem cells （ESCs） can undergo unlimited self-renewal and maintain pluripotency to differen- tiate into any cell type of the three germ layers. Extensive studies have shown ESC identity is regulated by tran...Embryonic stem cells （ESCs） can undergo unlimited self-renewal and maintain pluripotency to differen- tiate into any cell type of the three germ layers. Extensive studies have shown ESC identity is regulated by transcription factors, epigenetic regulators and multiple signal transduction pathways. However, the kinase regulation of pluripotency is not well understood. Here we show that the serine/threonine kinase PlM2, which is highly expressed in ESCs but not in somatic cells, functions as a crucial stemness regulator in ESCs. Knockout of Pim2 inhibits the self-renewal and differentiation capability of ESCs. Mechanistic studies identified that PIM2 can directly phosphorylate 4E-BP1, leading to release of elF4E which facili- tates the translation of pluripotent genes in ESCs. Our study highlights a novel kinase cascade pathway for ESC identity maintenance.展开更多
文摘开花时间对植物的繁殖成功至关重要。广泛分布的物种经常发生开花时间的分化,从而能够更好地适应不同的环境条件。为了探索植物开花行为发生适应性分化的分子机制,首先要明确调控开花行为的遗传通路。本文梳理了植物各类群调控开花时间的遗传通路,以期为开花时间适应性分化的分子机制研究提供依据。植物从营养生长向繁殖转变时,其开花行为主要受到光照、温度、水分等外界环境因子和赤霉素等内在因素的影响。通过对模式植物拟南芥(Arabidopsis thaliana)和其他类群的研究,总结出了调控植物开花时间的6条通路,包括日照长度和光质影响开花的光依赖通路,长时间冷暴露后促进植物开花的春化通路,高温或低温环境影响开花的温度通路,以及赤霉素通路、年龄通路和自主通路3条内部调节过程。植物开花时间调控的6条上游通路信号传递到下游的开花整合基因FT(FLOWERING LOCUS T)和SOC1(SUPPRESSOR OF OVER-EXPRESSION OF CONSTANS 1),整合基因将这些复杂的调节因子整合后进一步传递到下游花分生组织,从而启动开花。此外,非编码RNA、转座子对开花时间的调控也具有重要作用。部分遗传通路被证实在植物适应环境的过程中起到了重要作用。目前对植物开花调控的研究已经有一百多年历史,理论相对成熟。然而,仍然存在许多具有争议和未解决的问题,如开花基因的表达方式、开花行为的特殊调控机制、开花时间变异的适应性意义等等,需要更进一步的研究。
文摘脊椎动物的Dmrt(double-sex and mab-3related transcription factor)是指与果蝇Dsx基因和线虫Mab-3基因同源的基因家族。本文阐述了Dmrt家族中8个成员的基因和蛋白结构特征,并通过分析Dmrt在各类脊椎动物发育中的表达显示,Dmrt家族主要参与性别决定和性腺分化,也参与某些非性腺组织器官的发育:Dmrt1主要参与精巢分化,也与卵巢发育有关;Dmrt2主要参与体节的发生、分化以及非对称器官的形成;Dmrt3,4,5可共同参与或依次调控嗅器和脑的发育;Dmrt7为雄性配子发生所必须;Dmrt8属雄性偏向表达基因。Dmrt1在各脊椎动物的遗传性别决定通路中的位置和作用位点不同。
基金Project supported by the National Natural Science Foundation of China (No. 60105003) and the Natural Science Foundation of Zhejiang Province (No. 600025), China
文摘Mobile robot global path planning in a static environment is an important problem. The paper proposes a method of global path planning based on neural network and genetic algorithm. We constructed the neural network model of environmental information in the workspace for a robot and used this model to establish the relationship between a collision avoidance path and the output of the model. Then the two-dimensional coding for the path via-points was converted to one-dimensional one and the fitness of both the collision avoidance path and the shortest distance are integrated into a fitness function. The simulation results showed that the proposed method is correct and effective.
基金supported by the National Basic Research Program of China (2013CB966901)the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA01040108)The National Thousand of Talents Program to T.Z., and the National Natural Science Foundation of China (31570995, 31621004) to T.Z. and (31400831) to J.C.
文摘Embryonic stem cells （ESCs） can undergo unlimited self-renewal and maintain pluripotency to differen- tiate into any cell type of the three germ layers. Extensive studies have shown ESC identity is regulated by transcription factors, epigenetic regulators and multiple signal transduction pathways. However, the kinase regulation of pluripotency is not well understood. Here we show that the serine/threonine kinase PlM2, which is highly expressed in ESCs but not in somatic cells, functions as a crucial stemness regulator in ESCs. Knockout of Pim2 inhibits the self-renewal and differentiation capability of ESCs. Mechanistic studies identified that PIM2 can directly phosphorylate 4E-BP1, leading to release of elF4E which facili- tates the translation of pluripotent genes in ESCs. Our study highlights a novel kinase cascade pathway for ESC identity maintenance.
