血竭超临界提取物的降血糖作用及其机制研究

为了研究血竭超临界提取物的降血糖作用及其机制,用正常小鼠和四氧嘧啶糖尿病小鼠模型,以血糖、糖耐量为指标研究血竭超临界提取物的降糖作用。通过测定体外α-葡萄糖苷酶的活力,观察血竭超临界提取物对α-葡萄糖苷酶的抑制作用。结果发现血竭超临界提取物对正常小鼠空腹血糖无明显降低作用,能改善小鼠对蔗糖的耐受力,能降低四氧嘧啶诱导的糖尿病小鼠的空腹血糖水平,能抑制α-葡萄糖苷酶的活性。表明血竭超临界提取物对糖尿病小鼠有较好的降糖作用,对α-葡萄糖苷酶的抑制作用可能是其降血糖的机制之一。     

北京市门头沟区资源开发价值及其生态系统服务损失评估

运用市场价值法、机会成本法、恢复费用法和影子工程法等生态系统服务价值评价方法,结合实地调查,对1949—2006年北京市门头沟区煤矿资源开采及其生态系统服务损失进行了系统评估.结果表明：研究区煤矿开采主要导致固废处置与压占损失、塌陷区复垦成本与粮食损失、水源涵养损失、居民搬迁损失和水土流失损失;研究期间,门头沟区煤炭开采所造成的生态系统服务损失价值约543亿元, 是其市场销售价值（59亿元）的9倍左右, 且其很难或需要相当长时间才能得以恢复.     

基于钙黄绿素的荧光分光光度法测定谷胱甘肽

目的:基于钙黄绿素的荧光分光光度法建立一种测定谷胱甘肽的新方法。方法:在pH=8.0介质中,铜(Ⅱ)与钙黄绿素配位引起荧光猝灭,由于谷胱甘肽与铜(Ⅱ)的亲和力很强,可从钙黄绿素-铜离子的络合物中夺取铜离子而使钙黄绿素游离出来使荧光强度得以恢复,荧光恢复的程度与加入谷胱甘肽的浓度在一定浓度范围内成线性。结果:据此建立了一种测定谷胱甘肽的新方法,该方法的线性范围为2.0×10-6～1.4×10-5mol.L-1,F=8.1964C+196.43,检测限为1.0×10-6mol/L。结论:用此法测定谷胱甘肽简便快速,灵敏度高。     

Quantitative evaluation of Candia antarctica lipase B displayed on the cell surface of a Pichia pastoris based on an FS anchor system

A new approach is described to quantify the number of enzyme molecules, such as Candia antarctica lipase B, that are displayed on the cell surface of Pichia pastoris. Enhanced green fluorescent protein (EGFP) and Candida antarctica lipase B (CALB) were fused and displayed on the surface of P. pastoris by linking to the anchor flocculation functional domain of FLO1p from Saccharomyces cerevisiae. Confocal laser scanning microscopy, flow cytometry, and fluorescence spectrophotometry were used to monitor the fluorescence intensity of fused EGFP. Combined with the corresponding protein concentration detected in the medium, a standard curve describing the relationship between the fusion protein concentration and fluorescence intensity were obtained and could be used to number CALB displayed on the cell surface. The results showed that approx. 10⁴ molecules of CALB molecules were immobilized on the single P. pastoris cell wall based on FS anchor system.     

Inhibition of AMPK expression in skeletal muscle by systemic inflammation in COPD rats

Background

Chronic obstructive pulmonary disease (COPD) is a disease characterized by airflow limitation and inflammation. Meanwhile, COPD also is associated with metabolic disorders, such as skeletal muscle weakness. Strikingly, activation of AMP-activated protein kinase (AMPK) exerts critical roles in energy metabolism. However, it remains unclear whether and how the expression levels of AMPK are affected in the COPD model rats which may lead to the dysfunction of the skeletal muscle in these rats.

Methods

Here we developed a rat model of COPD, and we investigated the morphological changes of peripheral skeletal muscle and measured the levels of tumor necrosis factor -α (TNF-α) and AMPK in skeletal muscle by using approaches that include immunohistochemistry and polymerase chain reaction (PCR).

Results

We found that the expression levels of both AMPK mRNA and protein in skeletal muscles were significantly reduced in the COPD model rats, in comparison to those from the control rats, the COPD model rats that received treatments with AICAR and resveratrol, whereas the expression levels of TNF-α were elevated in COPD rats.

Conclusion

Such findings indicate that AMPK may serve as a target for therapeutic intervention in the treatment of muscle weakness in COPD patients.     

SYBR Green Ⅰ荧光定量RT-PCR检测埃博拉病毒方法的建立

为了建立一种快速准确的检测埃博拉病毒(EBOV)亚型的方法。本研究根据GenBank中公布的EBOV NP基因序列,通过设计引物和优化反应条件,建立了一种SYBR GreenⅠ荧光定量RT-PCR检测方法检测EBOV。以体外转录的EBOV RNA为模板进行试验,该方法检测的灵敏度可以达到1.0×102个拷贝/μL,检测范围达到9个数量级为102～1010,可检测5种亚型EBOV。建立的方法对马尔堡病毒(MARV)、登革病毒(DENV)、新疆出血热病毒(XHFV)、乙型脑炎病毒(JEV)、流感病毒(H1N1和H3N2)和猪繁殖和呼吸综合征病毒(PRRSV)E基因组RNA无非特异性扩增。本文将荧光定量RT-PCR技术用于埃博拉病毒的定量检测中,并且建立了EBOV SYBRGreenⅠ荧光定量RT-PCR检测方法。     

琵琶柴不同分支序级根系生物量分配格局的坡向差异

生物量分配模式影响植物获取资源以及竞争能力,不同序级根系分支生物量分配格局对理解植物的表型可塑性有重要意义。本研究利用Arc GIS建立研究区域的数字高程模型,采用全根系挖掘法,研究了祁连山北坡荒漠草原不同坡向琵琶柴(Reaumuria soongorica)1~3级根系的生物量分配格局。结果表明:不同坡向草地群落的盖度、密度、高度、物种丰富度、地上生物量和土壤含水量呈不同的变化趋势(P0.05),琵琶柴种群的密度、高度和根冠比等生物学特征的变化规律存在差异(P0.05);随着坡向由南坡转向西坡、东坡和北坡,琵琶柴1级根生物量比例呈逐渐增加趋势(P0.05),2级和3级根生物量比例呈逐渐减小趋势(P0.05);琵琶柴1级根生物量的增加速度大于2级和3级根的增加速度,2级与3级根生物量近等速增长。不同坡向琵琶柴根系合理权衡各级根系资源配置模式,反映了异质生境中植物种群应对资源多重竞争的环境适应机制。     

含三种群的植物病虫害模型的稳定性

考虑植物、害虫和害虫天敌三种群之间的关系,在人工喷洒杀虫剂作用下,建立一类新的三种群的植物病虫害模型.给出了模型无天敌病虫害平衡点和有天敌病虫害平衡点,利用Hurwitz定理和稳定性第一近似方法讨论了平衡点的稳定性,得到了两类平衡点渐近稳定的充分条件,并用Matlab进行了数值模拟,验证了结论的正确性.     

疏水修饰聚阳离子高分子SP-Chol 在COS-7 细胞中转染和毒性的研究

目的:研究以精胺为单体,以乙二醇二氯甲酸酯作为连接剂,以胆固醇氯甲酸酯作为疏水基团连接剂合成的疏水修饰聚阳离子高分子SP-Chol对非洲绿猴肾癌细胞COS-7的转染活性和细胞毒性的影响。方法:以荧光素酶质粒为报告基因,研究SP-Chol与DNA的复合物在COS-7细胞的转染活性,用MTT方法研究SP-Chol对COS-7细胞的毒性。结果:COS-7细胞实验显示,SP-Chol具有低于PEI 25kDa的细胞毒性,同时也具有高效输送DNA的能力。结论:SP-Chol是一种新型的高效、低毒,在基因治疗领域有潜在应用价值的非病毒基因输送载体。