Identification and functional characterization of CD133+GFAP+CD117+Sca1+ neural stem cells

Molecular and Cellular Biochemistry - Neural stem cells (NSCs) are responsible for maintaining the nervous system and repairing damages. Utility of NSCs could provide a novel solution to treat...     

GSK-3β inhibition protects human nucleus pulposus cell against oxidative stress-inducing apoptosis through mitochondrial pathway

Molecular Biology Reports - Oxidative stress in the intervertebral disc leads to nucleus pulposus (NP) degeneration by inducing cell apoptosis. However, the molecular mechanisms underlying this...     

A Novel Method for Fast Change-Point Detection on Simulated Time Series and Electrocardiogram Data

Although Kolmogorov-Smirnov (KS) statistic is a widely used method, some weaknesses exist in investigating abrupt Change Point (CP) problems, e.g. it is time-consuming and invalid sometimes. To detect abrupt change from time series fast, a novel method is proposed based on Haar Wavelet (HW) and KS statistic (HWKS). First, the two Binary Search Trees (BSTs), termed TcA and TcD, are constructed by multi-level HW from a diagnosed time series; the framework of HWKS method is implemented by introducing a modified KS statistic and two search rules based on the two BSTs; and then fast CP detection is implemented by two HWKS-based algorithms. Second, the performance of HWKS is evaluated by simulated time series dataset. The simulations show that HWKS is faster, more sensitive and efficient than KS, HW, and T methods. Last, HWKS is applied to analyze the electrocardiogram (ECG) time series, the experiment results show that the proposed method can find abrupt change from ECG segment with maximal data fluctuation more quickly and efficiently, and it is very helpful to inspect and diagnose the different state of health from a patient''s ECG signal.     

Cloning and Functional Expression of a Novel Geranylgeranyl Pyrophosphate Synthase Gene from Arabidopsis thaliana in Escherichia coli

A gene encoding a novel geranylgeranyl pyrophosphate (GGPP)synthase from Arabidopsis thaliana has been identified and termedGGPS5. The gene has been sequenced and expressed in Escherichiacoli. The deduced amino acid sequence showed 64.5% and 57.5%identity with a putative GGPP synthase from Arabidopsis andCapsicum annuum, respectively. GGPP enzymatic activity was detectedin E. coli cells expressing the GGPS5 gene in two differentways. One was the direct measurement of GGPP synthase activityin cell extracts and the other was the yellow color productionof cells when the GGPS5 gene was co-expressed with crtB, crtI,crtX, crtY and crtZ genes derived from Erwinia uredovora. (Received May 20, 1996; Accepted December 14, 1996)     

三个新2,2—二甲基苯并二氢吡喃类化合物的分离与鉴定

从中药三叉苦(Evodia lepta(Spreng.)Merr.)的地上部分分离鉴定了4个化合物。通过光谱解析和结构沟通的方法确定了它们的结构。其中3个为新化合物,依次命名为leptin A(Ⅰ)、leptin B(Ⅱ)和leptin C(Ⅲ)。另外一个已知化合物为异吴茱萸酮酚(Ⅳ)。     

Movement of outbreak populations of mountain pine beetle: influences of spatiotemporal patterns and climate

Insect outbreaks exert landscape-level influences, yet quantifying the relative contributions of various exogenous and endogenous factors that contribute to their pattern and spread remains elusive. We examine an outbreak of mountain pine beetle covering an 800 thousand ha area on the Chilcotin Plateau of British Columbia, Canada, during the 1970s and early 1980s. We present a model that incorporates the spatial and temporal arrangements of outbreaking insect populations, as well as various climatic factors that influence insect development. Onsets of eruptions of mountain pine beetle demonstrated landscape-level synchrony. On average, the presence of outbreaking populations was highly correlated with outbreaking populations within the nearest 18  km the same year and local populations within 6 km in the previous two years. After incorporating these spatial and temporal dependencies, we found that increasing temperatures contributed to explaining outbreak probabilities during this 15  yr outbreak. During collapse years, landscape-level synchrony declined while local synchrony values remained high, suggesting that in some areas host depletion was contributing to population decline. Model forecasts of outbreak propensity one year in advance at a 12 by 12  km scale provided 80% accuracy over the landscape, and never underestimated the occurrence of locally outbreaking populations. This model provides a flexible approach for linking temperature and insect population dynamics to spatial spread, and complements existing decision support tools for resource managers.     

小麦防御素基因TaPDF35的克隆与功能分析

从抗纹枯病小麦品种CI12633中克隆出一个小麦防御素基因TaPDF35,并对其表达特性及功能进行了分析。TaPDF35基因包含一个长为249 bp的开放阅读框(ORF,open reading frame),编码82个氨基酸组成的多肽TaPDF35。预测分析表明,TaPDF35能形成由1个α螺旋和3股反向平行的β-折叠片组成的αβ(CSαβ)基序,αβ(CSαβ)基序由8个半胱氨酸形成的4个二硫键固定。TaPDF35的N端有一段27个氨基酸的信号肽。表达分析结果表明,TaPDF35基因在抗纹枯病小麦品种CI12633和山红麦中的表达量显著高于在感纹枯病小麦品种扬麦158和温麦6号中的表达量;该基因在小麦的叶鞘和茎中均有表达,且受纹枯病原菌诱导而上调表达。利用大麦条形花叶病毒(BSMV,barley stripe mosaic virus)诱导的基因沉默技术(VIGS,virus-induced gene silencing)降低抗纹枯病小麦品种CI12633中TaPDF35基因的转录水平,再接种纹枯病原菌进行纹枯病抗性鉴定。结果显示,与接种BSMV:GFP的CI12633对照植株相比,TaPDF35表达水平降低的CI12633植株对纹枯病的抗性显著降低,表明TaPDF35表达是小麦防御纹枯病反应所需的。     

Mitochondrial permeability transition and cytochrome c release induced by selenite

Cytochrome c release and mitochondrial permeability transition (MPT) play important roles in apoptosis. In this study, we found that selenium, an essential trace element, induced mitochondrial membrane potential (Delta psi(m)) loss, swelling, and cytochrome c release in isolated mitochondria. All of the above observations were blocked by cyclosporin A (CsA), which is a specific inhibitor to permeability transition pore (PTP), indicating selenite-induced mitochondrial changes were mediated through the opening of PTP. In physiological concentration, selenite could induce mitochondria at low-conductance PTP 'open' probability, which is correlated to regulate the physiological function, whereas in toxic concentration, induce mitochondria at high-conductance PTP 'open' probability and rapidly undergo a process of osmotic swelling following diffusion toward matrix as for inducer (Ca(2+)/P(i)). Selenite also induced other mitochondrial marker enzymes including monoamine oxidase (MAO) and mitochondria aspartate aminotransferase (mAST). Oligomycin inhibited the selenite-induced cytochrome c release and Delta psi(m) loss, showing that F(0)F(1)-ATPase was important in selenite or Ca(2+)/P(i)-induced MPT.