An update on histone lysine methylation in plants

Histone methylation plays crucial roles in epigenetic regulation. The SET domain proteins are now recognized as generally having methyltransferase activity targeted to specific lysine residues of histones. The enzymes and their specific histone lysine methylation have enormous impacts on the regulation of chromatin structure and function. In this review, we discuss recent advances made on histone lysine methylations and their diverse functions in plant growth and development.     

The genome of Laccaria bicolor provides insights into mycorrhizal symbiosis

Mycorrhizal symbioses--the union of roots and soil fungi--are universal in terrestrial ecosystems and may have been fundamental to land colonization by plants. Boreal, temperate and montane forests all depend on ectomycorrhizae. Identification of the primary factors that regulate symbiotic development and metabolic activity will therefore open the door to understanding the role of ectomycorrhizae in plant development and physiology, allowing the full ecological significance of this symbiosis to be explored. Here we report the genome sequence of the ectomycorrhizal basidiomycete Laccaria bicolor (Fig. 1) and highlight gene sets involved in rhizosphere colonization and symbiosis. This 65-megabase genome assembly contains approximately 20,000 predicted protein-encoding genes and a very large number of transposons and repeated sequences. We detected unexpected genomic features, most notably a battery of effector-type small secreted proteins (SSPs) with unknown function, several of which are only expressed in symbiotic tissues. The most highly expressed SSP accumulates in the proliferating hyphae colonizing the host root. The ectomycorrhizae-specific SSPs probably have a decisive role in the establishment of the symbiosis. The unexpected observation that the genome of L. bicolor lacks carbohydrate-active enzymes involved in degradation of plant cell walls, but maintains the ability to degrade non-plant cell wall polysaccharides, reveals the dual saprotrophic and biotrophic lifestyle of the mycorrhizal fungus that enables it to grow within both soil and living plant roots. The predicted gene inventory of the L. bicolor genome, therefore, points to previously unknown mechanisms of symbiosis operating in biotrophic mycorrhizal fungi. The availability of this genome provides an unparalleled opportunity to develop a deeper understanding of the processes by which symbionts interact with plants within their ecosystem to perform vital functions in the carbon and nitrogen cycles that are fundamental to sustainable plant productivity.     

Guaranteed cost control for discrete-time networked control systems with random Markov delays

The guaranteed cost control for a class of uncertain discrete-time networked control systems with random delays is addressed.The sensor-to-controller (S-C) and contraller-to-actuator (C-A) random network-induced delays are modeled as two Markov chains.The focus is on the design of a two-mode-dependent guaranteed cost controller,which depends on both the current S-C delay and the most recently available C-A delay.The resulting closed-loop systems are special jump linear systems.Sufficient conditions for existence of guaranteed cost controller and an upper bound of cost function are established based on stochastic Lyapunov-Krasovakii functions and linear matrix inequality (LMI) approach.A simulation example illustrates the effectiveness of the proposed method.     

高性能耐候建筑钢的焊接性能研究

对高性能耐候建筑用钢的手弧焊和埋弧焊焊接接头力学性能、组织结构、最高硬度以及电化学腐蚀性能进行研究.试验结果表明,该钢具有优异的焊接性能、较低的焊接冷裂纹敏感性和良好的耐大气腐蚀性能.     

吉林省蚂蚁资源及其开发利用问题

在吉林省共获蚂蚁１８种，分隶于２亚科、１０属。优势种为黄墩蚁、异色草蚁、路舍蚁和双针蚁。可利用的资源种类主要有阿基隆林蚁、鼎突多刺蚁、日本弓背蚁、黄墩蚁、异色草蚁和血红林蚁等。蚂蚁机体富含蛋白质、氨基酸、维生素、微量元素及多种生物活性物质，具有较高的食用、药用价值。     

论大学生就业政策与高校教学质量的共振效应——以西藏高校为例

高校外部大学生就业政策与高校内部教学质量政策协调一致、产生共振效应,对全面提高高等学校教育质量至关重要.在西藏如何通过教育外部就业政策的调整,与教育内部协同一致、形成共振效应,实现配合高校内部深化教育改革,调动学生学习积极性,促进教育教学管理水平提高,为全面提高教育质量创造良好外部环境,具有现实意义和历史意义.2012年,西藏在这方面进行了有益的尝试,对公招考试进行了重大改革.在西藏教育厅的支持下,以西藏大学为主组建课题组,对此进行了专门追踪研究,结果显示改革取得良好效果,形成了共振效应,初步达到了预期目的,并为西藏其他人事考试制度的改革提供了有益的经验.     

基于修正势能泛函的三角形薄板位移元

提出一种如同ＢＣＩＺ单元一样简单的三角形板单元。但是，这种单元对任何网格划分都能通过分片检验，保证收敛，并且以较少的自由度获得相当高的计算精度。     

大型回转窑用耐火材料

本文简述了大型回转窑各部分的工作条件及窑衬的损坏状况,列举了国内外大型回转窑所用的耐火材料,阐明今后窑衬材料应向优质化、长寿化、配套化方向发展。     

绝热流动的R4O7C毛细管计算模型

顺应开展制冷工质替代研究的趋势 ,对 R2 2的替代工质三元非共沸混合工质 R40 7C在毛细管中的绝热流动进行了分析计算 ,分别建立了能量、质量方程和压降计算公式 ,并分别就过冷区和两相区作了理论求解 .将 R40 7C与 R2 2的计算结果进行了对应比较分析 ,该计算模型将对R40 7C空调系统的优化分析和控制提供了有效的部件性能分析方法     

基于多尺度目标匹配的M型超声图像插值方法

提出了一种基于多分辨分析的Ｍ 型超声图像插值方法．该方法适用于图像的单方向插值,如沿横轴或纵轴．首先对边界灰度线进行小波变换,在多尺度空间采用极值点匹配方法,对细节函数和近似函数分别分段插值,然后进行小波逆变换,得到目标灰度线．实验及应用表明,该方法插值后的图像可以较好地保持运动目标轨迹的连续性