Double-gating mechanism and diversity of an adenosine triphosphate (ATP)-sensitive K+ channel in neurons acutely dissociated from rat neocortex

Classically, ion channels are classified into 2 groups: chemical-sensitive (ligand-gated) and voltage sensitive channels. Single ATP-sensitive K⁺ (K-ATP) channel currents were recorded in acutely dissociated rat neocortical neurons using patch clamp technique. A type of K-ATP channel has been found to be gated not only by intracellular ATP, but also by membrane potential (V_m), and proved to be a novel mechanism underlying the gating of ion channels, namely bi-gating mechanism. The results also show that the K-ATP channels possess heterogeneity and diversity. These types of K-ATP channels have been identified in 40.12% of all patches, which are different in activation-threshold and voltage-sensitivity. The present experiment studied the type-3 K-ATP channel with a unitary conductance of about 80 pS in detail (n = 15). Taking account of all the available data, a variety of K-ATP channels are suggested to exist in body, and one type of them is bi-gated by both chemical substances and membrane potentials. This property of the K-ATP channels may be related to their pathophysiological function. Project supported by the National Natural Science Foundation of China and Natural Science Foundation of Guangdong Province     

新一代植物表型组学的发展之路

随着多种植物全基因组测序的完成, 科研人员越来越认识到植物表型研究的重要性, 并将其提升至“组学”的高度。植物表型组学是研究植物生长、表现和组成的科学, 能够有效追踪基因型、环境因素和表型之间的联系, 是突破未来作物学研究和应用的关键领域。该文介绍了植物表型采集分析经历的从手工测量计数的初始阶段到特定测量工具的辅助阶段再到高通量表型组学3个阶段; 提出了推动植物表型采集分析发展的3个要素: 表型组学研究设施、表型采集技术及图像数据分析方法; 进而详细阐述了表型组学设施的发展、国际上代表性的设施平台情况以及表型采集传感器和图像数据分析方法的发展, 并展望了植物表型组学未来的研究方向。     

茶树嫩枝扦插的高效方法

茶(Camellia sinensis)是世界上最重要的饮料作物之一, 随着种植面积的扩大, 茶苗的需求量也日益增加。传统的扦插育苗方式存在着生根难、周期长和取材难等问题, 因此优化扦插生根的方法十分重要。该研究以较易获得、但传统方法难以生根的绿色嫩枝为扦插材料, 首先对培养介质进行改良。与土培和水培相比, 利用海绵培养可以使茶树幼嫩插穗在1个月之内快速生根, 生根率达32.2%。其次, 对海绵培方法做进一步优化, 确定一芽一叶的幼嫩短穗生根潜力更佳; 同时, 添加生根粉能够促进茶树茎部愈伤组织与根系的形成, 其中1.25 g?L ^-1生根粉处理48小时对茶树扦插快速生根最有效, 生根率达42.0%。综上, 通过优化培养介质和扦插材料以及适当添加生根粉等措施, 建立了一种茶树高效嫩枝扦插生根的方法。该方法能够显著缩短嫩枝插穗的生根时间, 突破了扦插材料的限制, 有效降低了扦插成本, 具有重要的应用前景。     

眼镜熊对空间的利用

作者于１９９６年秋在泽西动物园以一个眼镜熊家庭（２．２）对笼舍空间和活动设施的利用进行了研究。从１９９６年１０月１４日￣１１月１６日,采用瞬间抽样方法,进行了４０个小时（６０个时间段,１２００次扫描）的行为观察。结果表明,所有的眼镜熊以同样的方式利用笼舍,对某些地点的利用超过其它地点,其中１１％￣１７％的地点被过度利用,占活动时间的７３％￣８６％。除成年雌性外,所有个体都利用所有的活动设施。然而,     

稻田蜘蛛群落对稻飞虱的控制功能作用研究

试验选用蜘蛛和飞虱田间的最大饱和容量（Ｋ）及最大增长倍数两个指数,探讨了稻田蜘蛛群落对飞虱的自然控制功能,首次提出天敌功能指数（ＥＦ）这一群落参数及其计算式ＥＦ＝（Ｓ＋Ｆ^s/p),试验证实ＥＦ值的升降与水稻受飞虱危害的程度呈现显的负相关,在田间及网罩内飞虱种群未来最大饱和容量Ｋ及增长倍数均随初始ＥＦ的升高而显著下降。天敌功能指数能较好地反映出天敌对飞虱各时段的控制作用。     

棉蚜(Aphis gossypii)种群寄主分化和季节分化的微卫星引物PCR研究

通过对棉蚜群体进行室外观察、室内培养和分子遗传标记的DNA多态性分析（用3个微卫星序列为引物进行PCR）等研究,结果表明：1、冬寄主（木槿、石榴和花椒）上棉蚜种群分化较小（种群相似笥指数在0.833-0.917之间）,而冬寄主种群和夏寄主（棉花和南瓜）种群之间有较大的分化（种群相似性指数在0.589-0.756之间）。2、棉蚜自然种群是由体色不变的生物型（干母为黄色,其后代始终为黄色）和体色可变型生物型（干母为绿色,其后代有绿色和黄色两种体色）组成的混合种群。3、黄色小型蚜（伏蚜）来源于混合类群,但主要来自绿色干母多代选择分化的黄色后代,也有小部分可能来处在干母黄色的体色不变型。     

DHPC: a new tool to express genome structural features

The DHPC (DNA Hilbert-Peano curve) is a new tool for visualizing large-scale genome sequences by mapping sequences into a two-dimensional square. It utilizes the space-filling function of Hilbert-Peano mapping. By applying a Gauss smoothing technique and a user-defined color function, a large-scale genome sequence can be mapped into a two-dimensional color image. In the calculated DHPCs, many genome characteristics are revealed. In this article we introduce the method and show how DHPCs may be used to identify regions of different base composition. The power of the method is demonstrated by presenting multiple examples such as repeating sequences, degree of base bias, regions of homogeneity and their boundaries, and mark of annotated segments. We also present several genome curves generated by DHPC to demonstrate how DHPC can be used to find previously unidentified sequence features in these genomes.     

Design and identification of selective HER-2 sheddase inhibitors via P1' manipulation and unconventional P2' perturbations to induce a molecular metamorphosis

In an effort to obtain a MMP selective and potent inhibitor of HER-2 sheddase (ADAM-10), the P1' group of a novel class of (6S,7S)-7-[(hydroxyamino)carbonyl]-6-carboxamide-5-azaspiro[2.5]octane-5-carboxylates was attenuated and the structure-activity relationships (SAR) will be discussed. In addition, it was discovered that unconventional perturbation of the P2' moiety could confer MMP selectivity, which was hypothesized to be a manifestation of the P2' group effecting global conformational changes.     

聚-β-羟基丁酸(PHB)在细菌建立感受态中的作用

介绍了PHB作为细胞膜上的物质运输通道成分在细菌感受态中的结构、分布、分析方法以及其可能的作用 ,阐明了PHB的合成与细菌感受态建立的关系和PHB在感受态细胞摄取外源DNA时的作用方式 ,同时也对控制生物体合成PHB的相关基因和酶作了简要介绍 ,并探讨了研究PHB的实际意义。