Features and trend of loss of promoter-associated CpG islands in the human and mouse genomes

CpG islands (CGIs) are often considered as gene markers, but the number of CGIs varies among mammalian genomes that have similar numbers of genes. In this study, we investigated the distribution of CGIs in the promoter regions of 3,197 human-mouse ortholo

Molecular Phylogeny and Phylogeography of Suidae

猪科动物是最为昌盛的哺乳动物之一,但它们的分类及系统发育关系却尚待解决。为此,用PCR直接测序法测定了一个红河猪(Potamochoerusporcus)、一个马来西亚野猪(Susbarbatus)以及数头欧亚野猪(Susscorfa)线粒体细胞色素b全序列1140bp。结合从GenBank中获得的其他猪科物种胞色素b序列,用邻接法和最大简约法构建了猪科物种的系统发育关系,其结果显示苏拉威西鹿猪与其他猪科物种为姐妹群的关系。非洲物种疣猪和河猪聚为一枝,而欧亚猪属物种聚为另一支。各物种在系统发育关系中的位置与它们的地理分布对应。猪属物种可以被划分为3个种组:分布于菲律宾群岛、苏拉威西岛及其邻近岛屿的猪属物种形成一个种组,包括苏拉威西岛疣猪、菲律宾疣猪和印度尼西亚疣猪;欧亚野猪种组,包括欧亚野猪和姬猪;须猪和爪哇疣猪形成一个种组。

一种改进的动物线粒体DNA提取方法

线粒体 DNA (mtDNA)已被广泛用于动物群体遗传学和进化生物学的研究, 并取得了许多有意义的结果. 有效的 mtDNA 提取方法无疑是开展这方面研究的前提. 关于动物 mtDNA 的提取方法, 国内外已有不少报导. 概括起来, 可分为: 1)氯化铯超速离心法, 2)柱层析法, 3)DNase法, 4)碱变性法. 该文报道了一种改进的碱变性提取法, 与其它方法相比, 具有应用范围广、简便、经济等优点。

Quantitative analysis of land mammal zoogeographical regions in China and adjacent regions

Quantitative analysis of land mammal zoogeographical regions in China and adjacent regions. Zoological Studies 43(1): 142-160. In this paper, our aim was to determine, by means of quantitative analysis, the distribution patterns of the land mammals in China and, adjacent regions using physiographical regions as operative geographical units (OGUs). Based, on the pre-sence or absence of 11 orders, 42 families, 197 genera, and 577 species of land mammals in their zoogeographical regions, which were used as OGUs, we studied the biotic boundary between the Oriental Region (OR) and the Palaearctic Region (PR), as well as subregion boundaries. The boundary's statistical significance was tested by G-test as described by McCoy et al. A significantly strong biotic boundary was found to separate the PR from the OR, and there is a weak biotic boundary in the PR, which divides it into 2 subregions. We concluded that the biotic boundary which separates the PR and OR is a strong boundary. We suggest that the Qinghai-Xizang Plateau should be regarded as a subregion of the PR, which can embody its characteristics of high elevations and a frigid climatic, which is called the Qing-Zang subregion of the PR (QZSP).

牛血清白蛋白对小鼠原核期胚胎玻璃化冷冻的影响

以小鼠原核期胚胎为对象, 以胚胎的存活率、卵裂率、囊胚率以及囊胚细胞数作为检测指标, 在M2 液的基础上添加8 种浓度(0 , 2 , 4 , 8 , 16 , 32 , 64 , 96 mg/ mL) 牛血清白蛋白(BSA) 配置防冻液, 探讨防 冻液和玻璃化冷冻后对胚胎发育的影响。BSA 防冻液对胚胎发育影响的实验结果表明, 8 个浓度组间以及与对 照组间胚胎的卵裂率、囊胚率以及囊胚细胞数无显著差异( P > 0105) , 说明在防冻液中加入一定浓度的BSA 对小鼠胚胎无毒性作用。防冻液经玻璃化冷冻后对胚胎发育影响的实验表明, 8 个浓度组间冷冻胚胎复苏后的 存活率、卵裂率、囊胚率及囊胚细胞数无显著差异( P > 0105) 。表明BSA 在这种防冻液中没有明显的保护作 用。从经济、实用、生物安全角度考虑, 不支持在玻璃化防冻液中添加BSA。

抑郁症首次发病患者静息态脑功能局部一致性的研究

下载PDF阅读器目的 利用功能磁共振(fMRI)和局部一致性(regional homogeneity,ReHo)探讨抑郁症首次发病(以下简称首发)患者在静息态脑功能是否存在异常及异常部位.方法 对34例符合美国精神疾病诊断与统计手册第4版诊断标准的首发抑郁症患者(抑郁症组)和34名性别、年龄、文化程度匹配的健康志愿者(对照组)进行静息态fMRI扫描.结果 抑郁症组静息态脑血氧水平依赖信号的ReHo高于对照组的脑区有左侧额叶眶回、顶下小叶、颞上回,右侧额内侧回、顶下小叶、小脑后叶;低于对照组的脑区有左颞下回、右颞上同和胼胝体、双侧后扣带回(P＜0.005,K≥10).结论首发抑郁症患者在静息态存在多个腩区功能活动的异常,并可能和抑郁症的病理机制有关.

Properties of the proton-evoked currents and their modulation by Ca2+ and Zn2+ in the acutely dissociated hippocampus CA1 neurons

The characterization of acid-sensing ion channel (ASIC)-like currents has been reported in hippocampal neurons in primary culture. However, it is suggested that the profile of expression of ASICs changes in culture. In this study, we investigated the properties of proton-activated current and its modulation by extracellular Ca2+ and Zn2+ in neurons acutely dissociated from the rat hippocampal CA1 using conventional whole-cell patch-clamp recording. A rapidly decaying inward current and membrane depolarization was induced by exogenous application of acidic solution. The current was sensitive to the extracellular proton with a response threshold of pH 7.0-6.8 and the pH(50) Of 6.1, the reversal potential close to the Na+ equilibrium potential. It had a characteristic of acid-sensing ion channels (ASICs) as demonstrated by its sensitivity to amiloride (IC50 = 19.6 +/- 2.1 muM). Either low [Ca2+](0) or high [Zn2+](0) increased the amplitude of the current. All these characteristics are consistent with a current mediated through a mixture of homomeric ASIC1a and heteromeric ASIC1a + 2a channels and closely replicate many of the characteristics that have been previously reported for hippocampal neurons cultured for a week or more, indicating that culture artifacts do not necessarily flaw the properties of ASICs. Interestingly, we found that high [Zn2+] (>10(-4) M) slowed the decay time constant of the ASIC-like current significantly in both acutely dissociated and cultured hippocampal neurons. In addition, the facilitating effects of low [Ca2+](0) and high [Zn2+](0) on the ASIC-like current were not additive. Since tissue acidosis, extracellular Zn elevation and/or Ca2+ reduction occur concurrently under some physiological and/or pathological conditions, the present observations suggest that hippocampal ASICs may offer a novel pharmacological target for therapeutic invention. (C) 2004 Elsevier B.V. All rights reserved.

EARLY MOTHER-INFANT RELATIONSHIPS OF MACACA-THIBETANA AT MT-EMEI CHINA

Quantitative data on early mother-infant relationships in the Tibetan macaque was collected during the first 23 weeks of infant life in spring, 1987, at Mt. Emei, China. During the first week of life, infants spent 98.3% of their time in ventroventral contact with their mothers. This contact rapidly decreased to 33.8% by the 4th week and thereafter to 0.85% by the 23rd week. Nipple contact decreased relatively slowly from 89.7% to 62.9% within the first 4 weeks of infant life and to 19.8% by the 23rd week. Ventrolateral and ventrodorsal contact appeared by the 2nd week, mean-while, maternal restraining behavior appeared, and reached a peak by the 3rd week. The mother neither encouraged nor discouraged her infant's independence during 4-8th weeks. Maternal rejection of the infant was first observed when the infant was 11 weeks old and continued thereafter.