The Hormonal Regulation of Flower Development

Homeotic genes comprising the ABCE classes partly detail the genetic networks that control aspects of floral organ initiation, development, and architecture, but less is known about how these gene functions are translated into changes at the cellular level in growth and cellular differentiation that are involved in the formation of diverse floral organs with specific shapes and sizes. Hormones are the principal transducers of genetic information, and due to recent advances in understanding hormone function in floral development, it is timely to review some of these findings. Flower development is the result of a regulated balance between meristem size and coordination and organ initiation. Floral meristem size is regulated by cytokinin, gibberellin, and auxin, and auxin plays a major role in organ initiation and organogenesis. How hormones contribute to the development of each organ is partly known, with stamen development reliant on almost all hormones, petal development is affected by gibberellins, auxin, and jasmonic acid, and gynoecium development is predominantly regulated by auxin. Furthermore, the interconnections between genetic hierarchies and hormones are being elucidated, and as almost all hormone groups are implicated in floral development, points of hormone crosstalk are being revealed.     

Intraspecific variation of thermal reaction norms for development in insects: New approaches and prospects

The main parameters (thermal constants) characterizing the effects of constant temperatures on the duration and rate of development in ectotherms are considered. The advantages and drawbacks of the linear and nonlinear models describing the dependence of the development rate on temperature are discussed. The main patterns of interspecific variation of thermal constants in insects are described. The development of new ideas in the study of intraspecific variation of thermal reaction norms for development in insects is examined. The discrepancies in the data and their interpretation in this field are shown to result mostly from using the traditional methods of determining thermal constants. According to this method, the development rates calculated as reciprocals of the mean development times at each experimental temperature are used for regression analysis. The standard errors calculated according to this method are usually too large. Instead, a fundamentally new method is employed by the authors, according to which the individual development rates calculated for each individual are used for regression analysis of the reciprocals of the mean development times. This method reduces the standard errors of thermal constants by about an order and reveals significant differences between populations and other groups of insects. New data on intraspecific variation of the thermal reaction norms for development in Myrmica ants, the linden bug Pyrrhocoris apterus, and Calliphora blowflies are briefly described and discussed. The possible adaptive significance of these forms of intraspecific variation is discussed. The prospects of research in this new field are outlined.     

京津唐城市生态系统能值比较

运用能值(emergy)分析方法,以京津冀地区的北京、天津、唐山为研究对象,建立了复合生态系统与可持续发展的能值指标,对3个城市1991～2005年自然环境与社会经济可持续发展状况进行了比较分析.研究结果表明:1991～2005年期间,由于北京、天津的本地资源能值对经济发展的驱动力不足,城市发展对外部输入能值的依赖程度越来越高;北京、天津、唐山社会子系统的能值指标均呈上升趋势,城市居民生活水平和经济发展水平不断提高;北京经济子系统的各项指标均优于天津和唐山,但环境子系统和能值可持续指标体现出,北京的环境压力最大、可持续发展能力低于天津和唐山.在此分析基础上,对北京、天津、唐山的可持续发展提出了几点建议,为制定城市发展策略和产业调整提供科学依据.     

Gonadal development and sex determination in mouse

The development of primordial germ cells and gonads are determinants of reproductive health and fertility. Although the gonadal development process is similar for both genders, the gender-determining process and the mechanism of development of female and male gonads have different molecular mechanisms. Spermatogenesis and oogenesis are also included in this process for a healthy gonadal development. Many specific molecular signaling pathways play role in oogenesis and spermatogenesis and it is important to know at which stage these factors are effective, to understand the mechanism of a healthy gonadal development. With this review, we defined the importance of stage specific genes expressing during the events such as oogenesis and spermatogenesis with the prenatal and postnatal gonadal development. It will be important to know about the cellular signals involved in the control of the gonadal development.     

Relative dental development of Upper Pleistocene hominids compared to human population variation

The relative development of permanent teeth in samples of Neandertal/archaic Homo and Early Modern/Upper Paleolithic hominids is compared to the range of variability found in three recent human samples. Both fossil hominid samples are advanced in relative M2 and M3 development compared to white French-Canadians, but only the Neandertal/archaic Homo M3 sample is advanced when compared to black southern Africans. Both fossil hominid samples are delayed in relative I1 and P3 development compared to the recent human samples. Two hypotheses concerning the significance of the advanced M3 and M2 development found in both hominid groups and southern Africans compared to French-Canadians are discussed. The first postulates that the differences in relative molar development are due simply to variation in tooth/jaw size relationships. The second postulates that the relatively advanced M3 and M2 development found in the fossil hominids and southern Africans is a correlate of their potential for advanced skeletal maturation compared to French-Canadians and other European-derived populations. It appears that dental development patterns have continued to evolve from the Upper Pleistocene to present times, and that Neandertals and Early Moderns shared similar patterns of relative dental development. © 1996 Wiley-Liss, Inc.     

Functional Compartments During Sporangium Development in the Pteridophyte Cyrtomium falcatum (L.f.) Presl as Expressed in Tapetum Function

Abstract: The tapetum surrounds the developing sporogenous tissue, and therefore is suggested to have an important role during sporogerlesis. In pteridophytes details about tapetum development and function during sporangium development are poorly known. The current article analyses the leptospor-angiate development of the pteridophyte Cyrtomium falcatum in terms of functional compartmentalization related to tapetum function. Morphology, development and localization of different compounds during sporangium development are studied. Dur ing C. falcatum leptosporangiate development phases of initia tion, division, differentiation, and maturation are identified. Functional compartments are distinguished by the presence of a callose culture sac during the division and differentiation phase, and a callose spore sac during the differentiation and ma turation phase.     

Mammalian oocyte growth and development in vitro

This paper is a review of the current status of technology for mammalian oocyte growth and development in vitro. It compares and contrasts the characteristics of the various culture systems that have been devised for the culture of either isolated preantral follicles or the oocyte-granulosa cell complexes from preantral follicles. The advantages and disadvantages of these various systems are discussed. Endpoints for the evaluation of oocyte development in vitro, including oocyte maturation and embryogenesis, are described. Considerations for the improvement of the culture systems are also presented. These include discussions of the possible effects of apoptosis and inappropriate differentiation of oocyte-associated granulosa cells on oocyte development. Finally, the potential applications of the technology for oocyte growth and development in vitro are discussed. For example, studies of oocyte development in vitro could help to identify specific molecules produced during oocyte development that are essential for normal early embryogenesis and perhaps recognize defects leading to infertility or abnormalities in embryonic development. Moreover, the culture systems may provide the methods necessary to enlarge the populations of valuable agricultural, pharmaceutical product-producing, and endangered animals, and to rescue the oocytes of women about to undergo clinical procedures that place oocytes at risk. © 1996 Wiley-Liss, Inc.     

miRNA在调控皮肤和毛囊发育中的作用

表皮发生和毛囊的周期性再生涉及一系列基因的激活和沉默。近年来的研究表明, miRNA的表达谱在表皮和毛囊组织中存在组织特异性, 在毛囊周期性发育中存在阶段特异性。大量miRNA参与表皮和毛囊的发生, 色素的沉着以及毛囊的周期性发育过程, 不同类型细胞中的miRNA通过与信号通路和调控因子相互作用形成了一个全方位、多层次的网络调控系统。文章综述了miRNA调控表皮内稳态和毛囊周期性发育的一些研究 进展, 旨在丰富miRNA参与的基因调控网路的研究, 进而为人工调控miRNA进行疾病治疗和分子育种提供 帮助。     

基于集对分析的京津冀区域可持续发展协调能力评价

区域发展的协调能力是区域可持续发展的重要表征之一。采用社会经济各相关部门的统计数据及资料,构建区域可持续发展评价指标和各级评价标准,利用集对分析中的同异反态势排序的协调发展评价模型实证分析了京津冀地区2000—2010年间的可持续发展协调能力。结果表明:(1)2000—2004年间北京和天津属于不协调发展,2006—2010年逐渐步入弱协调发展,但研究时段内河北省始终为不协调发展。(2)京、津和冀协调能力指数2010年相比2000年分别提高27.86%、8.87%和18.51%,各省域协调发展改善均不明显且步伐不一。(3)对京津冀区域各省域的发展提出了具体建议,但仍要加强各地区的合作和明确各自功能地位尤其重要。研究结果可以为京津冀整体规划的制定及实施提供科学依据和指导,也为环渤海经济圈可持续发展研究奠定了基础。     

基于主体功能区的长江经济带绿色发展评价与问题区域识别

长江经济带已成为我国推进绿色发展的重要阵地。基于主体功能区视角,构建以水系统为纽带的长江经济带绿色发展评价指标体系,采用综合加权法、空间自相关、耦合协调度模型等方法探究2018年长江经济带130个城市绿色发展及各子系统耦合协调水平的空间格局,并对绿色发展的问题区域进行分类识别。结果表明：(1)长江经济带绿色发展水平呈由下游、中游至上游递减趋势;各主体功能区绿色发展指数表现为优化开发区>限制开发区>重点开发区。(2)绿色发展各子系统耦合协调度值位于0.365—0.656之间,多处于濒临失调和勉强协调的临界区间,耦合协调水平整体偏低。(3)从长江经济带整体来看,长江中上游地区绝大部分城市绿色发展主要受资源利用和产业发展水平偏低,及由此带来的生态和生活问题限制,且长江中上游地区各省会或直辖市对区域内其他城市绿色发展带动能力不足。从主体功能区视角来看,优化开发区以生态问题为主,仅上海和嘉兴两市;重点开发区以生态和生产问题为主,集中于武汉都市圈和成渝双城经济圈内部;限制开发区以生产和生活问题为主,主要位于省际边界型城市地区。最后综合问题识别结果,分别对长江经济带各主要问题区域绿色发展...     

我国创新药研发模式与价值评估(I)

创新药研发对企业研发能力要求高,目前我国大部分药企仍然处于仿创阶段,但随着政策环境的改善,国家不断释放鼓励创新信号, 创新型药企不断涌现,传统药企积极布局,创新药物迎来发展机遇。借鉴国外创新药研发经验,探讨我国创新药的 3 种研发模式及估值方法, 解析创新药研发的机遇与风险。     

The ecologist's role in development for tourism: a case study in the Caribbean

Ecologists are increasingly in demand to provide both background information to development and to conduct validatory studies prior to funding. This paper describes an advisory study conducted on the Caribbean island of Mustique prior to development for tourism. It is argued that the ecologist uses biological as well as physical indicators to assess suitability of different areas for development and to anticipate possible problems. In this study the primary environmental determinants and biological and human factors have been interpreted to identify the distribution and degree of seriousness of exposure, erosion potential and water yield and quality. The compatibility of physical and ecological factors with different categories of proposed development have been assessed, and maps of vegetation, soil and exposure transferred onto gridded overlays. The use of these overlays combined with a consideration of the compatibilities permitted the degree of restraint to the various categories of development to be presented in map form. The problems that are likely to be encountered as a result of development are discussed, and finally it is suggested that the development be subjected to regular ecological monitoring.     

60 Years of Development of the Journal of Integrative Plant Biology

In celebration of JIPB's 60^th anniversary, this paper summarizes and reviews the development process of the journal. To start, we offer our heartfelt thanks to JIPB's pioneer Editors-in-Chief who helped get the journal off the ground and make it successful. Academic achievement is the soul of academic journals, and this paper summarizes JIPB's course of academic development by analyzing it in four stages: the first two stages are mostly qualitative analyses, and the latter two stages are dedicated to quantitative analyses. Most-cited papers were statistically analyzed. Improvements in editing, publication, distribution and online accessibility—which are detailed in this paper—contribute to JIPB's sustainable development. In addition, JIPB's evaluation index and awards are provided with accompanying pictures. At the end of the paper, JIPB's milestones are listed chronologically. We believe that JIPB's development, from a national journal to an international one, parallels the development of the Chinese plant sciences.     

Multiple origins of anural development in ascidians inferred from rDNA sequences

Ascidians exhibit two different modes of development. A tadpole larva is formed during urodele development, whereas the larval phase is modified or absent during anural development. Anural development is restricted to a small number of species in one or possibly two ascidian families and is probably derived from ancestors with urodele development. Anural and urodele ascidians constitute a model system in which to study the evolution of development, but the phylogeny of anural development has not been resolved. Classification based on larval characters suggests that anural species are monophyletic, whereas classification according to adult morphology suggests they are polyphyletic. In the present study, we have inferred the origin of anural development using rDNA sequences. The central region of 18S rDNA and the hypervariable D2 loop of 28S rDNA were amplified from the genomic DNA of anural and urodele ascidian species by the polymerase chain reaction and sequenced. Phylogenetic trees inferred from 18S rDNA sequences of 21 species placed anural developers into two discrete groups corresponding to the Styelidae and Molgulidae, suggesting that anural development evolved independently in these families. Furthermore, the 18S rDNA trees inferred at least four independent origins of anural development in the family Molgulidae. Phylogenetic trees inferred from the D2 loop sequences of 13 molgulid species confirmed the 18S rDNA phylogeny. Anural development appears to have evolved rapidly because some anural species are placed as closely related sister groups to urodele species. The phylogeny inferred from rDNA sequences is consistent with molgulid systematics according to adult morphology and supports the polyphyletic origin of anural development in ascidians. Correspondence to: W.R. Jeffery     

活性氧调控植物生长发育的研究进展

活性氧(ROS)是植物有氧代谢过程中的副产物, 它在植物的许多生命过程中均具有有害和有利的双重功能。ROS对细胞的氧化损伤作用和信号转导诱导植物防卫反应已有详尽的研究。近年来, 越来越多的关于ROS调控植物生长发育的证据开始引起了人们的广泛关注。细胞的生长是植物发育的重要部分, ROS通过直接或间接调节细胞的生长来控制植物的发育, 成为植物发育的重要调节剂。该文综述了羟自由基(.OH)及其前体超氧阴离子自由基(O2^–. )和过氧化氢(H₂O₂)调控植物生长发育的研究进展, 包括ROS调控植物不同器官生长的证据和机理、ROS产生的途径及其检测方法, 同时对今后的研究进行了展望。