145 resultados para 348-C0002P


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浑善达克沙地位于锡林郭勒高原中部,是我国干草原地带最大的一片沙地。由于长期过度利用,导致了草场退化、固定沙丘活化、沙地大面积沙漠化等一系列环境问题,防治沙漠化的进一步扩大已经刻不容缓。本论文的目的是了解沙地植被与环境的生态关系、沙生植物适应沙地环境的特点以及沙地植物资源特征,为在沙漠化防治中选择合适的治沙物种、制定合理的植被恢复方案提供理论依据。论文包括三方面的内容:1 浑善达克沙地丘间低地草本植物群落的分类与排序;2 沙埋对中间锦鸡儿幼苗生长发育的影响;3 浑善达克沙地植物资源分析。 对丘间低地的草本植物群落进行TWINSPAN 分类和DCA 排序结果表明,浑善达克沙地中部研究区域丘间低地植物群落可分成四个主要类型,每个类型各具不同的特点,土壤盐分以及相关的土壤水分因素对群落分布有着显著的影响。在沙地环境中,沙埋是影响植物幼苗存活的一个重要因素。中间锦鸡儿(Caragana intermedia)是浑善达克沙地和毛乌素沙地固定和半固定沙丘上常见的一种沙生灌木。为了研究沙埋对其幼苗的存活以及生长的影响,对出土后生长了一个月的中间锦鸡儿实生苗进行沙埋实验,实验处理有对照、部分沙埋和全埋,结果表明,部分沙埋对中间锦鸡儿幼苗的生长发育没有显著的影响,说明中间锦鸡儿是一个比较耐沙埋的物种,尽管全部沙埋对其幼苗的生长发育产生了显著的抑制。 浑善达克沙地的物种资源丰富,有种子植物约952 种,分布在348 属、75 科中,菊科和禾本科是最大的两个科;草本植物是主要的生活型,有828 种,占物种总数的86.97%;植物的水分生态类型以中生植物最多,有577 种,占物种总数的61.1%,其次为旱生植物291 种,占总数的30.8%;沙地中有优良牧草植物149 种,可用于固沙的植物几十种,有药用价值的植物约301 种。

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Multidirectional comparative chromosome painting was used to investigate the karyotypic relationships among representative species from three Feliformia families of the order Carnivora ( Viverridae, Hyaenidae and Felidae). Complete sets of painting probes derived from flow-sorted chromosomes of the domestic dog, American mink, and human were hybridized onto metaphases of the spotted hyena (Crocuta crocuta, 2n = 40) and masked palm civet (Paguma larvata, 2n = 44). Extensive chromosomal conservation is evident in these two species when compared with the cat karyotype, and only a few events of chromosome fusion, fission and inversion differentiate the karyotypes of these Feliformia species. The comparative chromosome painting data have enabled the integration of the hyena and palm civet chromosomes into the previously established comparative map among the domestic cat, domestic dog, American mink and human and improved our understanding on the karyotype phylogeny of Feliformia species. Copyright (C) 2005 S. Karger AG, Basel.

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从广西产眼镜王蛇( Ophiophagus hannah) 毒腺中抽提总RNA , 经mRNA 纯化后构建眼镜王蛇毒腺 cDNA 文库。从所构建的cDNA 文库中, 随机筛选200 个克隆测序, 得到两个在进化上高度保守的基因: 泛素融 合蛋白基因(GenBank 登录号为AF297036) 和核糖体蛋白L30 基因(GenBank 登录号是AF297033) 。前者cDNA 的开放阅读框为387 bp , 后者为348 bp 。前者编码128 个氨基酸残基组成的泛素融合蛋白前体; 后者编码115 个氨基酸残基组成的核糖体蛋白L30 前体。由cDNA 序列推导出的氨基酸序列分析表明, 泛素融合蛋白前体包 括N - 末端的泛素结构域(76 个氨基酸残基) 和C - 末端的核糖体蛋白L40 结构域(52 个氨基酸残基) 。该蛋 白为一高碱性蛋白, C 末端含有一个“锌指”模式结构。与16 个物种比较的结果表明, 眼镜王蛇与脊椎动物的 泛素融合蛋白氨基酸序列相似度较高, 具有高度的保守性。

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The energy substrates lactate, pyruvate, and glucose were evaluated for supporting in vitro cytoplasmic maturation of rhesus monkey oocytes. A total of 321 cumulus-oocyte complexes (COCs) aspirated from greater than or equal to 1000 mum diameter follicles

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Mutation C1494T in mitochondrial 12S rRNA gene was recently reported in two large Chinese families with aminoglycoside-induced and nonsyndromic hearing loss (AINHL) and was claimed to be pathogenic. This mutation, however, was first reported in a sample f

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Eastern and western populations of the ranid frog Odorrano chapaensis from Vietnam and China are readily differentiated by morphology and mtDNA, and weakly differentiated by morphometrics. The western population contains the type localities of O. chopoens

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研究了人类精液中幼稚生殖细胞的微核率和男性不育的关系。无精症或多精 症患者, 其精液缺乏幼稚生殖细胞而未能进行微核测定。微核率最高可达122‰ ,最低为16‰。微核率与对照组相比有显著升高, 高微核率还伴随有减数分裂不 分离以及出现高比例的二倍体及四倍体精子。并讨论了生殖细胞微核率增高作 为不育症的一个可能病因以及微核测定的临 床使用价值。图版1表1参16

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