Mountains are important reservoirs of biodiversity and endemism on a global scale, but little is known about the altitudinal configuration of this diversity and its driving factors in arid mountains. We explored varia...Mountains are important reservoirs of biodiversity and endemism on a global scale, but little is known about the altitudinal configuration of this diversity and its driving factors in arid mountains. We explored variations in composition, diversity, cover,and life forms of vascular plants along a complete altitudinal gradient(1300-4000 m a.s.l) in Sierra de Velasco, an arid mountain in northwestern Argentina.We evaluated the influence of environmental variables on plant diversity and cover. Field sampling was conducted in the northern sector of the Sa. de Velasco,on the western slope in eight 50 m wide altitudinal bands at 400 m elevation intervals. We used rectangular plots(20 × 4 m;n:10/altitudinal band) to register the vascular plants of all the growth forms, and linear transects(20 m long.;n:30/altitudinal band) to quantify the vegetation cover using the point intercept method. Diversity was calculated using hill numbers.Data analysis included non-metric multidimensional scaling(NMDS), indicator species analysis,generalized linear models(GLMs), and variance partitioning analysis. A total of 232 species from 51families and 158 genera were registered. Species composition showed greater similarity at intermediate elevations. Plant diversity and cover exhibited a unimodal distribution, peaking at intermediate elevations(2100-2500 m). In contrast, life forms' distribution showed divergent patterns. Therophytes and succulents predominated at low altitudes,phanerophytes and hemicryptophytes at medium altitudes, and chamaephytes and geophytes at high altitudes. The altitudinal patterns of plant diversity and cover were primarily driven by climatic factors.Conservation efforts in the Sierra de Velasco should focus on the middle and upper zones due to their high biodiversity and vulnerability to climate change.展开更多
Among various architectures of polymers,end-group-free rings have attracted growing interests due to their distinct physicochemical performances over the linear counterparts which are exemplified by reduced hydrodynam...Among various architectures of polymers,end-group-free rings have attracted growing interests due to their distinct physicochemical performances over the linear counterparts which are exemplified by reduced hydrodynamic size and slower degradation.It is key to develop facile methods to large-scale synthesis of polymer rings with tunable compositions and microstructures.Recent progresses in large-scale synthesis of polymer rings against single-chain dynamic nanoparticles,and the example applications in synchronous enhancing toughness and strength of polymer nanocomposites are summarized.Once there is the breakthrough in rational design and effective large-scale synthesis of polymer rings and their functional derivatives,a family of cyclic functional hybrids would be available,thus providing a new paradigm in developing polymer science and engineering.展开更多
基因疗法是将基因导入靶细胞内,以纠正缺陷和异常基因引起的疾病的治疗方法。目前,多个基因治疗药物已经进入临床研究阶段或已上市,为癌症、罕见病、神经性疾病等多个领域的疾病治疗带来了希望。基因治疗中最关键的步骤就是如何将外源...基因疗法是将基因导入靶细胞内,以纠正缺陷和异常基因引起的疾病的治疗方法。目前,多个基因治疗药物已经进入临床研究阶段或已上市,为癌症、罕见病、神经性疾病等多个领域的疾病治疗带来了希望。基因治疗中最关键的步骤就是如何将外源基因准确安全地导入宿主细胞。腺相关病毒(adeno-associated virus, AAV)载体是当前最受欢迎的人类基因治疗载体之一,它是唯一能定点整合到人类基因组特定位点的病毒载体。AAV定点整合的位点AAVS1 (the adeno-associated virus site 1)已经被证明是安全的基因整合位点。本实验以Rep蛋白介导基因定点整合至人T淋巴细胞基因组AAVS1位点,随后采用标准曲线定量的方法,对混合细胞克隆AAVS1位点的定点整合率进行定量。实验进行两轮PCR,首先通过常规PCR扩增包含ITR-AAVS1结合位点的序列,然后取标准品和检测样本第一轮PCR产物作为模板,进行第二轮定量PCR。通过本实验中的研究方法可以简单快速地定量分析AAVS1定点整合率。展开更多
In order to investigate the mode of action ofYimu Shenghuasan preparation in endometrial cells of dairy cows, the primary cultured endometrial cells in cows were isolated and the inflammatory models were made by lipop...In order to investigate the mode of action ofYimu Shenghuasan preparation in endometrial cells of dairy cows, the primary cultured endometrial cells in cows were isolated and the inflammatory models were made by lipopolysaccharide （LPS） induction. The inflammatory cells were treated with gradient concentration of herbal medicine preparation, Yimu Shenghuasan for 48 and 72 h. The expression of cytochrome P450 （CYP450） was detected by Western blot. The amounts of IgG and lgA in sera were also detected in the endometritis of dairy cows. The expression level of CYP450 in the endometrial cells of dairy cow was increased gradually, and the amounts of IgG, IgA were increased significantly as compared with those in the control group. The expression level of CYP450 in the inflammatory cells was increased significantly in the treatment of 2 000 μg mL^-1 of Yimu Shenghuasan after 48 h of treatment.展开更多
文摘Mountains are important reservoirs of biodiversity and endemism on a global scale, but little is known about the altitudinal configuration of this diversity and its driving factors in arid mountains. We explored variations in composition, diversity, cover,and life forms of vascular plants along a complete altitudinal gradient(1300-4000 m a.s.l) in Sierra de Velasco, an arid mountain in northwestern Argentina.We evaluated the influence of environmental variables on plant diversity and cover. Field sampling was conducted in the northern sector of the Sa. de Velasco,on the western slope in eight 50 m wide altitudinal bands at 400 m elevation intervals. We used rectangular plots(20 × 4 m;n:10/altitudinal band) to register the vascular plants of all the growth forms, and linear transects(20 m long.;n:30/altitudinal band) to quantify the vegetation cover using the point intercept method. Diversity was calculated using hill numbers.Data analysis included non-metric multidimensional scaling(NMDS), indicator species analysis,generalized linear models(GLMs), and variance partitioning analysis. A total of 232 species from 51families and 158 genera were registered. Species composition showed greater similarity at intermediate elevations. Plant diversity and cover exhibited a unimodal distribution, peaking at intermediate elevations(2100-2500 m). In contrast, life forms' distribution showed divergent patterns. Therophytes and succulents predominated at low altitudes,phanerophytes and hemicryptophytes at medium altitudes, and chamaephytes and geophytes at high altitudes. The altitudinal patterns of plant diversity and cover were primarily driven by climatic factors.Conservation efforts in the Sierra de Velasco should focus on the middle and upper zones due to their high biodiversity and vulnerability to climate change.
基金Supported by the National Natural Science Foundation of China(Nos.52293472,22473096 and 22471164)。
文摘Among various architectures of polymers,end-group-free rings have attracted growing interests due to their distinct physicochemical performances over the linear counterparts which are exemplified by reduced hydrodynamic size and slower degradation.It is key to develop facile methods to large-scale synthesis of polymer rings with tunable compositions and microstructures.Recent progresses in large-scale synthesis of polymer rings against single-chain dynamic nanoparticles,and the example applications in synchronous enhancing toughness and strength of polymer nanocomposites are summarized.Once there is the breakthrough in rational design and effective large-scale synthesis of polymer rings and their functional derivatives,a family of cyclic functional hybrids would be available,thus providing a new paradigm in developing polymer science and engineering.
文摘基因疗法是将基因导入靶细胞内,以纠正缺陷和异常基因引起的疾病的治疗方法。目前,多个基因治疗药物已经进入临床研究阶段或已上市,为癌症、罕见病、神经性疾病等多个领域的疾病治疗带来了希望。基因治疗中最关键的步骤就是如何将外源基因准确安全地导入宿主细胞。腺相关病毒(adeno-associated virus, AAV)载体是当前最受欢迎的人类基因治疗载体之一,它是唯一能定点整合到人类基因组特定位点的病毒载体。AAV定点整合的位点AAVS1 (the adeno-associated virus site 1)已经被证明是安全的基因整合位点。本实验以Rep蛋白介导基因定点整合至人T淋巴细胞基因组AAVS1位点,随后采用标准曲线定量的方法,对混合细胞克隆AAVS1位点的定点整合率进行定量。实验进行两轮PCR,首先通过常规PCR扩增包含ITR-AAVS1结合位点的序列,然后取标准品和检测样本第一轮PCR产物作为模板,进行第二轮定量PCR。通过本实验中的研究方法可以简单快速地定量分析AAVS1定点整合率。
基金supported by the National Technology Support Project of China(2006BAD04A10-4)
文摘In order to investigate the mode of action ofYimu Shenghuasan preparation in endometrial cells of dairy cows, the primary cultured endometrial cells in cows were isolated and the inflammatory models were made by lipopolysaccharide （LPS） induction. The inflammatory cells were treated with gradient concentration of herbal medicine preparation, Yimu Shenghuasan for 48 and 72 h. The expression of cytochrome P450 （CYP450） was detected by Western blot. The amounts of IgG and lgA in sera were also detected in the endometritis of dairy cows. The expression level of CYP450 in the endometrial cells of dairy cow was increased gradually, and the amounts of IgG, IgA were increased significantly as compared with those in the control group. The expression level of CYP450 in the inflammatory cells was increased significantly in the treatment of 2 000 μg mL^-1 of Yimu Shenghuasan after 48 h of treatment.
