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1.
目的:了解实验性高胆固醇血症家兔血液流变特性的改变与动脉粥样硬化形成的关系。方法:健康家兔80只,随机分为实验组(AG)60只和对照组(CG)20只。各组又均分为4个亚组,即AG1-AG4和CG1-CG4。AG组每只给予胆固醇粉1g/d,在喂养的第2、4、8和12周分别观察AG1-CG1、AG2-CG2、AG3-CG3和AG4-CG4的主动脉粥样硬化(AS)病变及相应血液流变特性的变化。结果:在兔  相似文献   

2.
n个群体的p维环境因子主成分分析(PCA),Z=U’X,恢复原始数据线性表达成X=UZ,依据λ值,取前-1r个主成分,1≤r≤p,将P维环境因子降维成1元向量,建立前r个主成分的生态梯度轴(EGA(PCr)],估算误差为d(j)。对白榆全分布区20个群体的样点6维环境因子PCA求算的EGA(PCr),取r=1,2,3,建立3个生态梯度轴,累计贡献率依次为63.8%,84.3%和96.0%,都能较好的代表环境因子,EGA(PCr)在揭示群体7个性状的梯度变异中得到验证,并能用于判别种群变异模式。  相似文献   

3.
本实验应用免疫组织化学方法,检测巨噬细胞相关抗原、巨噬细胞集落刺激因子(M┐CSF)、白细胞介素┐1(IL┐1)和肿瘤坏死因子┐α(TNF┐α)在骨巨细胞瘤(GCT)中的表达,结果表明,在GCT中,M┐CSF主要由纤维母细胞样基质细胞(FC)分泌;巨噬细胞样基质细胞(HC)是单核┐巨噬细胞系早期的未成熟细胞,主要分泌IL┐1和TNF┐α,少数多核巨细胞(MGC)也可产生TNF┐α。本文提示,GCT中的三种主要细胞能分泌M┐CSF、IL┐1和TNF┐α细胞因子,通过自分泌或旁分泌作用相互影响,共同促进GCT的发生、发展及其侵袭性的生物学行为  相似文献   

4.
野生大豆与栽培大豆rDNA ITS1区的研究   总被引:9,自引:0,他引:9  
采用PCR 技术从野生大豆(Glycine soja)、半野生大豆(G.gracillis)、多年生野生大豆(G.tomentella、G.tabacina)和栽培大豆(G.m ax)的两个品种UNION、文丰7 中扩增和克隆了rDNA第一转录间隔区(ITS1)。其在G.m ax 基因组中的拷贝数约为2×103。序列分析表明G.soja、G.gracillis、G.m ax 中的G/C含量为61.40% ,而G.tabacina和G.tom entella的G/C含量分别为58.11% 和59.01% ,与绿豆G/C含量(59.81% )相近。G.tabacina的G/C含量是已知的植物中ITS1 最低的。最大同源性分析表明,大豆属植物ITS1 的同源程度很高,同其近缘属绿豆的同源性明显高于其它作物。同时分析了栽培、多年生和一年生野生大豆间的亲缘关系。另外还发现在已知的植物ITS1 序列中均含有GACCCGCGAA 及GCGCCAAGGAA 两个区段  相似文献   

5.
人粒细胞-巨噬细胞集落刺激因子基因表达受到转录调控与转录后调控。5'非转录区的一些顺式调控成分,如CATT(A/T)重复序列,富含GC序列,CK-1、CK-2、kB特异序列与可诱导的CsA敏感增强子成分等在转录水平上调控hGM-CSF的表达。3'非翻译区有一62bp富含AU序列,这与mRNA的稳定性相关,在翻译水平调控hGM-CSF的表达,细胞因子与一些刺激因子通过不同的机制作用于hGM-CSF基  相似文献   

6.
北京东灵山地区农耕干扰和环境梯度对植物多样性的影响   总被引:2,自引:0,他引:2  
于北京东灵山地区,选取10条样带、94个样方、15个环境因子,采用主成分分析和相关分析研究了东灵山地区人为干扰(如农耕)及其造成的环境条件变化对植物α多样性的影响.(1)调查结果表明:植物群落可归入4类土地利用类型(农田、撂荒地、灌丛和林地)中;(2)主成分分析和相关分析表明:2个主成分(地形和土壤因子)影响着植物群落结构、物种组成和多样性的变化,尤其是海拔梯度与多数环境因子显著相关,起决定性作用;(3)多样性分析表明:Shannon-Wiener指数和Margalef指数都能较好地反映植物群落α多样性的变化,Simpson指数变化不明显.4种土地利用类型中植物群落α多样性的变化依次为:林地〉农田〉撂荒地〉灌丛,且草本层对植物多样性的贡献最大.  相似文献   

7.
黄瓜花发育的早期均有雌蕊和雄蕊原基的分化,但在发育过程中,由于雌蕊或雄蕊的发育受到阻滞,导致雄花和雌花的形成。近年来在拟南芥和金鱼草等植物中遗传学的研究表明,花器官的特征是由同源异形基因决定的。在拟南芥中,由于AG在决定雄蕊和雌蕊特征方面起重要作用,本研究利用 RT-PCR技术,从黄瓜的雌、雄蕊中分离出 AG的同源基因,并对其在花发育过程中的表达和可能作用进行了分析。首先,根据AG同源基因的保守区域设计5’简并引物5’-GA(A/G)AT(T/C/A)AA(T/C/A)AA(G/A)(A/C)G(G/T/C)ATCGA(C/A)AAC-3’,然后进行3’,RA CE PCR,扩增出约1kb大小的片段,序列分析表明该片段含有非常保守的MADS box。进而,利用5’ RACE PCR得到全长度的cDNA。该cDNA的核苷酸序列与CUM1(黄瓜 MADS box gene1)同源性高达97%。 CUM1在接牵牛中过量表达可引起花萼变为心皮状和花瓣变为雄蕊,说明CUM1为AG的同源基因。基于该基因与CUM1序列上的高度同源,我们认为其为黄瓜的AG同源基因。该基因命名为CMB1,基因银行登记号为AF286649。Souther  相似文献   

8.
几种扩血管多肽对bFGF促血管平滑肌细胞增殖作用的影响   总被引:3,自引:0,他引:3  
目的和方法:研究肾上腺髓质素(Adm)、降钙素基因相关肽(CGRP)及C-型心房利太(CNP)对碱性成纤维细胞生长因子(bFGF)促血管平滑细胞(VSMC)增殖作用的影响及其机制。结果:孵育24h后,bFGF刺激VSMC增殖较对照组增加2.1倍(P〈0.01),细胞内蛋白磷酸化程度增加1.4倍(P〈0.01),PKC及MAPK活性分别增加1.5和2.5倍(P〈0.010;Adm.CGRPt CNP  相似文献   

9.
转录因子与DNA的结合是基因转录的关键环节,通过迁移性法分析季转录因子AP1、cDAMP反应元件结合蛋白(CREB)、糖皮质激素反应元件(GRE)结合蛋白在衰老细胞中的结合活性,结果表明,AP1与CREB的结合活性在衰老细胞中对表皮生长因子(EGF)的反应性低于年轻细胞;而GRE结合蛋白的结合活性在衰老细胞中对EGF的反应性无明显变化,这提示EGF不能有效刺激衰老细胞增殖可能与其转录因子结合活性的  相似文献   

10.
采用逆转录-PCR方法,用3对引物分3个片段扩增强毒克隆(A9v)及弱毒克隆(A3%)的M基因片段cDNA,并克隆入pGEM-T载体中。采用Sanger双脱氧法测定了A39s、A9v病毒G1糖蛋白编码区的全序列,发现二者均由1978个核苷酸组成,比76/118株少6个核苷酸,并发现A39s在G1编码区有33个碱基及8个氨基酸与A9v不同。进一步与76/118、HV114的相关序列比较,发现G1编码区的第606、614位氨基酸的变异同A39s病毒的减毒有一定相关。从A39s、A9v、76/118及HV1144株病毒G1糖蛋白编码区推导的氨基酸序列亲疏水性资料显示,在位于G1糖蛋白C末端的最大亲水区域的600~620位氨基酸区域,弱毒株A39s同强毒株A9v、76/118、HV114的亲水性有明显不同,而这一差异又主要由第614位氨基酸的变异所引起。因此推测,G1糖蛋白C端亲水区域同汉滩病毒毒力相关,而第614位的精氨酸被谷氨酰胺取代,同A39s病毒毒力的减弱可能有关。  相似文献   

11.
动物与其生存环境变量之间的关系一直是生态学家们广泛关注的问题.啮齿动物作为荒漠生态系统中重要的功能群,其数量大小和生态功能对生态系统的平衡和稳定具有重要意义.生境中的植被为啮齿动物提供赖以生存的食物资源和栖息地,了解啮齿动物群落与植被特征之间的关系对于理解动物群落变动规律具有重要意义.不同植被条件下啮齿动物群落的结构不同,Hernández等(2005)研究发现北美Chihuahuan荒漠的灌木生境中啮齿动物密度高于草地生境.  相似文献   

12.
张炳  黄和平  毕军 《生态学报》2009,29(5):2473-2480
区域生态效率(eco-efficiency)评价是考量区域可持发展的重要内容.基于物质流分析(material flow analysis, MFA)构建区域生态效率评价指标体系,并将污染物排放作为一种非期望输入引入到数据包络分析(data envelopment analysis, DEA)模型中,以江苏省(1990~2005年)为例进行生态效率分析评价.结果表明,江苏省的区域生态效率在1990~2005年期间呈现逐步上升的趋势.但是,同期的总物质投入(total material input, TMI)、物质需求总量(total material requirement, TMR)和污染物排放量也呈上升趋势.因此,江苏省社会经济发展和环境影响总体上呈现"弱脱钩(weak de-link)".  相似文献   

13.
A microtechnique was developed for the quantification of indole-3-acetic acid (IAA) in plant samples of one milligram fresh weight or less. The method permitted quantification of both free and conjugated IAA using a benchtop gas chromatograph-mass spectrometer. New methods for sample purification with high recovery at microscale levels, together with simple changes that result in enhanced sensitivity of the instrumentation, allowed for a significant reduction in the amount of plant material required for analysis. Single oat (Avena sativa L.) coleoptile tips could be studied with this method and were found to contain free and total IAA levels of 137 and 399 pg · mg−1 fresh weight, respectively. A single 5-d-old Arabidopsis thaliana (L.) Heynh. seedling was shown to contain 61 pg · mg−1 fresh weight free IAA and 7850 pg · mg−1 fresh weight of total IAA following basic hydrolysis. This microtechnique provides a way to accurately measure IAA levels in very small structures and individual seedlings, thus making it a valuable research tool for elucidating the role and distribution of auxin in relation to growth and development. Received: 1 May 1994 / Accepted: 25 June 1997  相似文献   

14.
15.
采用协惯量分析(PCA-CA COIA)和典范对应分析(CCA)两种排序方法, 对北京小龙门林场的黄檗 (Phellodendron amurense)群落进行了分析, 并用Spearman秩相关系数检验了对应排序轴的相关性。两种排序方法得出的结果基本一致, 两者的第一排序轴都反映了海拔高度和坡向对群落分布的影响, 而各自第二、第三排序轴所代表的环境意义有所差异, 并出现了交叉, 但是两者的前3个排序轴均反映了海拔、坡位、土壤厚度和凋落物层厚度的变化趋势, 说明在环境因子个数较少或共线性效应不明显的情况下, 协惯量分析也能达到CCA的分析效果, 并且在排序轴特征值解释量上高于典范对应分析。  相似文献   

16.
A review is provided of the several bivariate generalisations of quantal response analysis that have appeared in the biometric and econometric literatures. There are three main types: (i) where a binary outcome is the result of two stimulants, and thus the bivariate distribution of the thresholds for response is relevant; (ii) where three or more alternative outcomes may arise from a single stimulant; and (iii) where the response itself is bivariate (i.e., two types of response may simultaneously be observed).  相似文献   

17.
Oils of various species of Copaifera are commonly found in pharmacies and on popular markets and are widely sold for their medicinal properties. However, the chemical variability between and within species and the lack of standardization of these oils have presented barriers to their wider commercialization. With the aim to recognize patterns for the chemical composition of copaiba oils, 22 oil samples of C. multijuga Hayne species were collected, esterified with CH2N2, and characterized by GC‐FID and GC/MS analyses. The chromatographic data were processed using hierarchical cluster analysis (HCA) and principal component analysis (PCA). In total, 35 components were identified in the oils, and the multivariate analyses (MVA) allowed the samples to be divided into three groups, with the sesquiterpenes β‐caryophyllene and caryophyllene oxide as the main components. These sesquiterpenes, which were detected in all the samples analyzed in different concentrations, were the most important constituents in the differentiation of the groups. There was a prevalence of sesquiterpenes in all the oils studied. In conclusion, GC‐FID and GC/MS analyses combined with MVA can be used to determine the chemical composition and to recognize chemical patterns of copaiba oils.  相似文献   

18.
The composition of the cuticular n‐alkanes isolated from the leaves of nine populations of Juniperus deltoides R.P.Adams from continental and coastal areas of the Balkan Peninsula was characterized by GC‐FID and GC/MS analyses. In the leaf waxes, 14 n‐alkane homologues with chain‐lengths ranging from C22 to C35 were identified. n‐Tritriacontane (C33) was dominant in the waxes of all populations, but variations between the populations in the contents of all n‐alkanes were observed. Several statistical methods (ANOVA, principal component, discriminant, and cluster analyses) were used to investigate the diversity and variability of the cuticular‐leaf‐n‐alkane patterns of the nine J. deltoides populations. This is the first report on the n‐alkane composition for this species. The multivariate statistical analyses evidenced a high correlation of the leaf‐n‐alkane pattern with the geographical distribution of the investigated samples, differentiating the coastal from the continental populations of this taxon.  相似文献   

19.
Several tools exist for the analysis of the environmental impacts of chains or networks of processes. These relatively simple tools include materials flow accounting (MFA), substance flow analysis (SFA), life-cycle assessment (LCA), energy analysis, and environmentally extended input-output analysis (IOA), all based on fixed input-output relations. They are characterized by the nature of their flow objects, such as products, materials, energy, substances, or money flows, and by their spatial and temporal characteristics. These characteristics are insufficient for their methodological characterization, and sometimes lead to inappropriate use. More clarity is desirable, both for clearer guidance of applications and for a more consistent methodology development. In addition to the nature of the flow object and to spatial and temporal characteristics, another key feature concerns the way in which processes are included in a system to be analyzed.
The inclusion of processes can be done in two fundamentally different ways: according to a full mode of analysis, with the inclusion of all flows and related processes to their full extent as present in a region in a specific period of time; and according to an attribution mode, taking processes into account insofar as these are required for a given social demand, function, or activity, in principle whenever and wherever these processes take place. This distinction, which cuts across families of tools that traditionally belong together, appears to have significant methodological and practical implications. Thus the distinction between the two modes of analysis, however crucial it may be, strengthens the idea of one coherent family of tools for environmental systems analysis.  相似文献   

20.
Abstract

A therapeutic rationale is proposed by selectively targeting tyrosine kinase 2 (TYK 2) to obtain potent TYK 2 inhibitors by molecular modeling studies. In the present study, we have taken tyrosine kinase (TYK 2) inhibitors and carried out molecular docking, 3?D quantitative structure–activity relationship (3D-QSAR) analysis and molecular dynamics (MD). Based on the 3D-QSAR results thirteen new compounds (R-1 to R-13) were designed and synthesized in good yields. The synthesized molecules were evaluated for their in vitro anticancer activity against LnCap and A549 cell lines. The molecules R-1, R-3, R-5, R-7, and R-10 exhibited considerable anti cancer activity.  相似文献   

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