225 resultados para 624.042.7


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从构建具有稳定泌氨能力的联合固氮工程菌的目的出发,首先构建Enterobacter gergoviae57-7 (E57-7)基因文库并与所筛选的泌氨突变株进行遗传互补实验,得到可互补 泌氨特性的克隆,经Southern杂交后推测其中包含与glnA、amtB基因无关的另一类与泌 氨相关的基因。同时根据铵载体基因amtB的已知序列设计两对简并性引物,经PCR从 E57-7 DNA中扩增得到约340bp的片段,序列分析和Blast序列同源性比较后确定为amtB 基因片段,申报并获得序列号AJ132232,最终从基因库中筛选到两个包含E57-7 amtB 基因的克隆。 用K. pneumoniae的glnA基因片段为探针,通过Southern杂交从E57-7基因库中筛选到包含有glnAntrBC基因的克隆,经亚克隆后对包含有这个操纵元的4316bp片段进行了全序列分析,申报GenBank获得序列号AF072440。在体外实验中构建了Km-cassette 插入glnA的重组质粒pA,将此质粒转入E57-7野生型菌株后经筛选同源重组子获得glnA 突变的具有稳定泌氨能力的菌株15、I9。并进行了盆栽玉米接种实验,确定在灭菌上壤实验体系下I5对玉米幼苗有显著促生效应。 利用绿色荧光蛋白(GFP-S65T,V68L,S72A)基因建立分子生物学研究手段,构建了新 型克隆载体pGreenLD,建立了绿白斑筛选重组质粒的的技术。构建组成型表达gfp的质粒载体研究了E57-7在玉米根际的定殖模式;构建nifH-gfp表达载体,确定在与植物联合生活时其固氮酶结构基因nifHDK的表达与碳源物质供应密切相关。利用不同抗性基因和gfp基因片段构建出在E57-7中组成型表达抗性和GFP的质粒载体,建立了监测接种菌在土壤中释放的双标记系统。 最后克隆了E57-7 glg cluster并测定部分glgCA和glgP基因序列,申报后获得序列号AJ132233和AJ132234,这是首例从联合固氮菌中克隆得到glg cluster的报道。

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疏花水柏枝(Myricaria laxiflora(Franch.)P.Y.Zhang et Y.J.Zhang)是我国三峡特有植物,是目前发现的唯一一种三峡水库蓄水后将被全部淹没的高等植物物种。本文结合前人的研究,通过详细的野外调查,摸清了疏花水柏枝的野生种群的分布及自然环境状况,较为全面、系统地研究了其生物学、群落学、种群学、生殖生态学等各方面的特征。最后,对其繁殖技术进行了着重研究,并提出了疏花水柏枝的的保护对策。 疏花水柏枝分布于我国亚热带长江三峡地区,位于东经109-0 32’~110-042、北纬30-0 59’~ 31-05’,海拔70 - 150米的范围内。疏花水柏枝为常绿灌木,具有很强的耐水淹的特性。其群落的植物区系组成中,以北温带分布和世界分布属为主,在各群落中疏花水柏枝均为建群种。在较小的尺度上(间距1m或更小),各群落中的疏花水柏枝种群均表现为聚集分布;在较大的尺度上(间距1.44m或更大),砾质地表的几个群落中疏花水柏枝种群表现为聚集分布,而沙质地表的群落中则表现为随机分布;幼苗在各种尺度上均表现为强烈的聚集分布。不同的群落中,疏花水柏枝种群的生物量有很大差异,变化范围为2,13 lt/hm2~5.340t/hm2,平均值为3.976t/hm2。疏花水柏枝的种群总体年龄结构比较稳定,但在不同的群落中差异较大。疏花水柏枝的的结实率高达95.12%,单位面积出种量平均为1.242×1()9粒/hm2。种子细小,寿命较短,新鲜饱满种子发芽率可达100%。冬季干旱和夏季水淹导致幼苗大量死亡。疏花水柏枝的扦插繁殖可获得较高的生根率,一年生插条的生根率明显高于多年生的插条。扦插苗移栽的成活率较高,并于第二年即可开花结实。种子繁殖也可获得较高的出苗率,但幼苗的死亡率很高。为保护这个物种,首先应加强宣传力度,进一步加强繁殖技术的研究,各北京植物园应大量引种栽培,并对其进行全面深入的研究,最终将其完全回归大自然。

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以中国东北森林 - 草原样带(NECT)上的松嫩平原羊草草甸草原为研究对象,从影响羊草叶片光合作用的机理出发,基于羊草片光合生理生态特性、羊草群落小气候梯度以及羊草群落生物量等的野外动态观测,分析了羊草叶片的光合生理特性动态特征,建立了羊草叶片的光合作用机理模型,通过尺度化,发展了基于叶片生理特性的羊草群落生产力动态模型;并结合著名的草地生态系统模型—CENTURY模型探讨了人类活动和气候变化对羊草草地的影响。主要结果如下: (1) 晴朗天气下羊草叶片气孔导度和净光合速率日变化均呈双峰型曲线。 (2) 影响羊草叶片气孔导度的主要环境因子是光合有效辐射、叶片与空气间的水汽压亏损以及空气温度。 (3) 影响羊草叶片净光合速率的主要因子是胞间CO2浓度、气孔导度、空气CO2浓度及蒸腾速率。 (4) 对当前2类代表性气孔导度模型的验证表明,基于Jarvis模型所改建的气孔导度模型比依据Leuning改进的Ball模型所建立的气孔导度模型具有更好的模拟效果,并据此建立了适于羊草叶片的气孔导度模型: gs = PAR (-2.01Ta2 + 147.74Ta - 2321.11)/((444.62 + PAR) (-538.042 + VPD)) (5) 结合能量平衡方程和光合作用生化模型,建立了能够模拟羊草叶片CO2、水汽和热量交换的羊草叶片光合作用耦合模型。该模型有能力预测复杂的环境变化对羊草叶片净光合作用和气孔导度的影响。 (6) 通过尺度化(采用多层模式模拟冠层导度,大叶模式模拟光合作用),建立了羊草群落光合作用模型,结合植物群落的呼吸模型,估算了羊草群落的净第一性生产力,并与实测值及CENTURY模型模拟值进行了比较,结果表明,基于叶片光合机理的群落生产力模型较CENTURY模型能更好地反映羊草群落的生产力动态。 (7) 基于CENTURY模型对人类活动、气候变化对羊草草原可能影响的模拟表明,人类活动(割草和放牧)和气候变化都会明显影响羊草草原,但人类活动产生的影响更为显著,尤其是重牧将造成羊草草原土壤有机碳和群落生物量显著降低。因此,制定合理的放牧和割草措施对于维持草场的可持续发展具有重要意义。

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Multidirectional chromosome painting with probes derived from flow-sorted chromosomes of humans (Homo sapiens, HSA, 2n = 46) and galagos (Galago moholi, GMO, 2n = 38) allowed us to map evolutionarily conserved chromosomal segments among humans, galagos, a

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Limited information is available on the prevalence among rural Africans of host genetic polymorphisms conferring resistance to HIV-1 infection or slowing HIV disease progression.We report the allelic frequencies of the AIDS-related polymorphisms CCR2-64I, SDF1-3#A, and CCR5-D32 in 321 volunteers from 7 ethnic groups in Cameroon. Allelic frequencies differed among the 7 ethnic groups, ranging from 10.8% to 31.3% for CCR2-64I and 0.0% to 7.1% for SDF1-3#A. No CCR5-D32 alleles were found. HIV seroprevalence was 6.9% in the total population and peaked at younger ages in girls and women than in boys and men. Among 15- to 54-year-olds, HIV seroprevalence varied from 2.0% to 11.1% among the village populations. Conditional logistic regression analysis using data from boys and men aged 15 to 54 years showed the number of CCR2-64I alleles to be a significant risk factor for HIV seropositivity (odds ratio per allele adjusted for age and matched on ethnic group = 6.3, 95% confidence interval: 1.3–30.3); this association was not found in women. The findings are consistent with the hypothesis that CCR2-64I alleles may delay HIV disease progression without affecting susceptibility to infection among men. We did not observe this relation among women, and other factors, such as multiple pregnancies or maternal stressors (eg, breastfeeding), may have masked any protective effect of CCR2-64I alleles. Further study of this issue among women is warranted. SDF1-3#A did not differ between HIV-seropositive and HIV-seronegative individuals but wasassociated with increasing age among HIV-seronegative women, suggesting a protective effect against HIV-1 infection.

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测定人猿超科(人、黑猩猩、大猩猩、红毛猩猩和长臂猿)和旧大陆猴(猕猴和叶猴)7种高等灵长类FKN全基因序列,探讨其系统进化分析.用简并引物PCR(Degenerated PCR)法分别扩增FKN的3个外显子,其产物经琼脂糖凝胶回收、纯化后测序,然后用BioEdit软件剪切拼接FKN基因全序列,用DNAStar比对后比较基因和氨基酸序列同源性,Mega软件重构FKN基因进化树,应用Datamonkey分析FKN的负选择位点.序列分析发现人猿超科较旧大陆猴FKN基因除了有散在的点突变外,还有一明显的30 bp的核苷酸缺失突变;人FKN基因序列与黑猩猩、大猩猩、红毛猩猩、长臂猿、猕猴和叶猴的同源性分别是99.2%、98.4%、98.1%、96.5%%、95.95和93.8%,由此推导的氨基酸序列同源性分别是98.5%、98.0%、97.7%、94.7%、93.7%和90.5%;FKN基因进化树表明人与黑猩猩关系更近,FKN基因进化和通常认为的物种进化一致;Datamonkey分析结果显示FKN存在3个负选择位点53Q.84D、239N.成功获得人、黑猩猩、大猩猩、红毛猩猩、长臂猿、猕猴和叶猴7种高等灵长类物种FKN全基因序列,为后续探讨FKN在高等灵长类物种进化过程中免疫学功能演变及其结构与功能的关系奠定基础. 作 者: 洪晓武 张亚平 储以微 高海峰 蒋正刚 熊思东 HONG Xiao-Wu ZHANG Ya-Ping CHU Yi-Wei GAO Hai-Feng JIANG Zheng-Gang XIONG Si-Dong 作者单位: 洪晓武,储以微,高海峰,蒋正刚,熊思东,HONG Xiao-Wu,CHU Yi-Wei,GAO Hai-Feng,JIANG Zheng-Gang,XIONG Si-Dong(复旦大学上海医学院免疫学系,免疫生物学研究所,上海,200032) 张亚平,ZHANG Ya-Ping(中国科学院昆明动物研究所细胞与分子进化开放实验室,昆明,650223) 刊 名: 遗传 ISTIC PKU 英文刊名: HEREDITAS 年,卷(期): 2008 30(5) 分类号: Q94 关键词: 人猿超科 旧大陆猴 FKN 测序 进化分析 机标分类号: R5 S86 机标关键词: 大陆灵长类全基因序列测定系统进化分析phylogenetic analysis基因进化树黑猩猩序列同源性长臂猿物种进化猕猴红毛负选择氨基酸琼脂糖凝胶基因全序列序列分析位点软件重构 基金项目: 国家自然科学基金,复旦大学校科研和教改项目 DOI:

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目的探讨p53基固在乳腺癌发生早期的作用及早期诊断乳晾瘟的分子病理指标。方法用PCR—sso 法检测36例乳腺单纯性增生、31例不典型增生、14例原位癌和16例程润癌中p53基因第7外显子突变,井用叭A 直接测序技术确定突变的碱基及其所在的密码子。结果乳腺单纯性增生、不典型增生、原位癌、浸润癌中|】53基 因第7外显于的突变率分别为0%、6 5%(2/31)、21 4%(3/14)、18.8%(3/16)。8例突变中,3例发生于251密码 子,4例发生手248密码子,I例发生于236密码子。表现为碱基替换(5例)、缺失(2例)、插入(J例)共二种突变方 式。并在I例原位瘟中首次发现了251密码子的同义突变(ATC斗ATr,异亮氨酸一异亮氮酸)。结论乳腺癌不典 型增生中存在053基因第7外显子突变,该突变可能在乳腺不典型增生发展到乳腺癌的过程中起霞要作用,可作为 早期诊断乳腺癌的辅助指标。

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长蠹科昆虫严重危害林木和仓贮物品。该文应用非损伤性DNA测序技术测定了来自不同国家的长蠹科害虫的线粒体DNAND4基因的部分序列。在获得的 2 0 4bp的序列中 ,7种昆虫的序列变异丰富 ,多数变异发生在密码子的第 3位点上。将实验结果与形态学特征比较分析 ,探讨 7个种的形态差异与基因序列的差异 ;结果表明 ,7种昆虫不仅在外形特征上存在差异 ,而且在ND4基因序列上的差异程度也很显著 ,平均为 2 1 94%。这为分类鉴定提供了充分的证据。

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An association of the dopamine receptor D4 (DRD4) gene located on chromosome 11p15.5 and attention deficit/hyperactivity disorder (ADHD) has been demonstrated and replicated by multiple investigators. A specific allele [the 7-repeat of a 48-bp variable number of tandem repeats (VNTR) in exon 3] has been proposed as an etiological factor in attentional deficits manifested in some children diagnosed with this disorder. In the current study, we evaluated ADHD subgroups defined by the presence or absence of the 7-repeat allele of the DRD4 gene, using neuropsychological tests with reaction time measures designed to probe attentional networks with neuroanatomical foci in D4-rich brain regions. Despite the same severity of symptoms on parent and teacher ratings for the ADHD subgroups, the average reaction times of the 7-present subgroup showed normal speed and variability of response whereas the average reaction times of the 7-absent subgroup showed the expected abnormalities (slow and variable responses). This was opposite the primary prediction of the study. The 7-present subgroup seemed to be free of some of the neuropsychological abnormalities thought to characterize ADHD.

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The pantherine lineage of the cat family Felidae (order: Carnivora) includes five big cats of genus Panthera and a great many midsized cats known worldwide. Presumably because of their recent and rapid radiation, the evolutionary relationship among pantherines remains ambiguous. We provide an independent assessment of the evolutionary history of pantherine lineage using two complete mitochondrial (mt) genes (ND2 and ND4) and the nuclear beta-fibrmogen intron 7 gene, whose utility in carnivoran phylogeny was first explored. The available four mt (ND5, cytb, 12S, and 16SrRNA) and two nuclear (IRBP and TTR) sequence loci were also combined to reconstruct phylogeny of 14 closely related cat species. Our analyses of combined mt data (six genes; approximate to 3750 bp) and combined mt and nuclear data (nine genes; approximate to 6500 bp) obtained identical tree topologies, which were well-resolved and strongly supported for almost all nodes. Monophyly of Panthera genus in pantherine lineage was confirmed and interspecific affinities within this genus revealed a novel branching pattern, with P. tigris diverging first in Panthera genus, followed by P. onca, P. leo, and last two sister species P. pardus and P. uncia. In addition, close association of Neofelis nebulosa to Panthera, the phylogenetic redefinition of Otocolobus manil within the domestic cat group, and the relatedness of Acinonyx jubatus and Puma concolor were all important findings in the resulting phylogenies. The potential utilities of nine different genes for phylogenetic resolution of closely related pantherine species were also evaluated, with special interest in that of the novel nuclear beta-fibrinogen intron 7. (c) 2005 Elsevier Inc. All rights reserved.

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本发明提供化合物5,6-二羟基-2-(4-羟苯基)-4-酮-4H-1-苯并吡喃基-7-羟基-β-D-葡萄糖醛酸在制备抗艾滋病药物中和在制备逆转录酶抑制剂药物中的应用。

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本发明属于医药技术领域,公开了毛蕊异黄酮-7-氧-β-D-吡喃葡萄糖苷或其盐的新的医药用途。经药理试验证明,毛蕊异黄酮-7-氧-β-D-吡喃葡萄糖苷或其盐具有抗艾滋病毒作用,可治疗艾滋病,可在制备抗艾滋病药物中应用。

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Przewalskin A (1), a novel C-23 terpenoid with a 6/6/7 carbon ring skeleton, was isolated from Salvia przewalskii. Its structure was determined by comprehensive 1D NMR, 2D NMR, and MS spectroscopic analysis and subsequently confirmed by a single-crystal X