不稳定型心绞痛患者血小板计数对低分子肝素抗凝有效性的影响

目的：通过检测抗Xa因子活性,探讨不稳定型心绞痛患者血小板计数（PLT）对低分子肝素抗凝有效性的影响。方法：入选不稳定型心绞痛患者63例,分为两组,A组（n=24）：PLT≥240×10^9／L,B组（n=39）：PLT〈240×10^9／L。首先比较两组患者之间一般情况有无差异,而后在两组患者皮下注射那曲肝素前及注射后8h两个时间点分别进行抗Xa因子活性检测并记录结果,分析两组患者抗Xa因子活性水平并比较活性低于0．5IU·mL^-1患者所占比例。结果：两组患者之间一般情况无显著性差异,抗Xa因子活性治疗前后差异在两组中均有统计学意义,A组治疗后抗Xa因子活性均值低于B组,抗Xa因子〈0．5IU·mL-1的患者比率高于B组,组间比较差异显著。结论：在低分子肝素抗凝治疗中,血小板计数≥240×10^9／L的惠者抗Xa因子活性较低,提示不稳定型心绞痛患者在应用低分子肝素后的抗凝力度不足与血小板计数偏高相关。     

濒危羊踯躅子代幼苗遗传多样性的SSR分析

利用本课题组此前开发的20对多态性较高的羊踯躅SSR引物,分析来自3个省份的4个羊踯躅野生幼苗自然居群(共64个株系)的遗传多样性和遗传结构,以期为羊踯躅保护提供科学依据。结果显示:(1)20对SSR引物共扩增出314个等位基因,每个SSR位点的平均等位基因数为15.700,多态信息含量PIC和有效等位基因数N_e的均值分别为0.850和4.457。(2)羊踯躅幼苗自然居群的基因多样性指数H和Shannon多样性指数I的均值分别为0.717和1.557,其中江西金溪(JX)居群的遗传多样性最丰富,浙江磐安(PA)的最低。(3)基于无限等位基因模型(IAM)分析发现,羊踯躅幼苗种群的基因流N_m和遗传分化系数F_(st)分别为1.372和0.155;AMOVA分析表明,羊踯躅幼苗种群的86.0%变异发生于居群内,仅有14%变异发生在居群间。(4)遗传距离法聚类NJ分析和Structure分析结果基本一致,分别聚为3大类和4大类。综合比较分析发现,羊踯躅幼苗种群中的各个遗传多样性相关的指标参数均低于成年自然居群,表明生境片段化已对羊踯躅的生存构成了极大的威胁。     

内蒙古黑里河自然保护区蝴蝶种类初报

2004~2006年初步查清内蒙古黑里河自然保护区的蝴蝶种类,隶属于7科,37种,其中凤蝶科Papilionidae 2种、粉蝶科Pieridae 7种、眼蝶科Satyridae 6种、蛱蝶科Nymphalidae 16种、灰蝶科Lycaenidae 2种、弄蝶科Hesperiidae 3种、绢蝶科Parnassiidae 1种。     

西双版纳片断化望天树林气候边缘效应比较研究

对西双版纳片断望天林树（Shorea chinensis)林林缘小气候的季节、水平变化进行了观测研究,对比分析了4个个不小雨林斑块（30hm^2,25hm^2,20hm^2,3hm^2)的小气候边缘效应。结果表明：各雨林斑块林缘均存在明显的小气候边缘效应,其中在干季晴天最为明显,且在上较小斑块林缘出现最高气温及气日较差高于林外的现象;干季,部分林缘小气候要素（最高气温、总辐射、净辐射、最小相对湿度）林缘与林内的差值均是高于或大于雨季的相应值,而地表最高温林缘与林内的差值则是雨季强于干季,各斑块相比,小气候边缘效应波及林内的深度在最大斑块达至最浅（25m),而在最小斑块达到最深（35m)呈现出小气候边缘效应及其影响深度随片继雨林斑块面积减小而增强及向林内进一步延伸的趋势。     

High-level expression of fusion protein containing 10 tandem repeated GLP-1 analogs in yeast Pichia pastoris and its biological activity in a diabetic rat model

Glucagon-like peptide-1 (GLP-1), an incretin secreted by intestinal L-cells, can effectively lower blood glucose levels in patients with diabetes. A fusion gene, consisting of 10 tandem repeated GLP-1 analog genes, was expressed at a high level in the yeast Pichia pastoris. SDS polyacrylamide gel electrophoresis (SDS-PAGE), and Western Blotting results showed that fusion protein migrated as a single protein band with a molecular weight of 36 kDa. A biological activity test showed that the GLP-1 analog could significantly lower the level of serum glucose when GLP-1 purified analog was injected into diabetic rats. A potential strategy for large-scale production of fusion protein containing the 10 GLP-1 analogs as discovered, and a single GLP-1 analog was obtained from fusion protein digested with trypsin. This should be inspired foreign expression of medicinal short peptides and be valuable in further research on GLP-1 analog drugs in the treatment of diabetes mellitus.     

siRNA沉默HIF-1α对胎肝基质细胞SDF-1α表达的影响

为了研究低氧诱导因子(hypoxia inducible factor-1alpha,HIF-1α)在干细胞增殖分化过程中的作用机制,构建了2个HIF-1α慢病毒siRNA干涉载体,并转染人胎儿肝脏基质细胞(fetal liver stromal cell,FLSC).根据绿色荧光蛋白的表达评估转染效率后进行流式细胞分选,获得高表达慢病毒干涉载体的细胞.实时荧光定量PCR和蛋白质印迹检测了转染细胞中HIF-1α基因的干涉效率,结果显示,与对照组相比,常氧下培养的细胞HIF-1α基因表达量仅为其相对表达量的18.8%和25.5%,干涉效率分别为81.2%和74.5%,低氧处理后的细胞HIF-1α相对表达量分别为对照组的21.2%和29.3%,干涉效率分别为78.8%和70.7%,均具有显著差异.蛋白质印迹结果显示,在蛋白质水平表达也明显受抑制,且重组干涉质粒pSicoR-HIF-1α1的干涉效应较强.RT-PCR、免疫荧光和ELISA法检测了沉默HIF-1α后胎肝基质细胞衍生因子1α(SDF-1α)在RNA和蛋白质水平的表达变化,干涉后细胞SDF-1α的表达明显减低.低氧条件下SDF-1α基因的调控作用有可能是通过低氧激活HIF-1α而诱导产生的,HIF-1α在干细胞增殖分化的分子调控机制中具重要作用.     

Protein arginine methyltransferase 5 is essential for growth of lung cancer cells

PRMT5 (protein arginine methyltransferase 5) is an enzyme that catalyses transfer of methyl groups from S-adenosyl methionine to the arginine residues of histones or non-histone proteins and is involved in a variety of cellular processes. Although it is highly expressed in some tumours, its direct role in cancer growth has not been fully investigated. In the present study, in human lung tissue samples we found that PRMT5 was highly expressed in lung cancer cells, whereas its expression was not detectable in benign lung tissues. Silencing PRMT5 expression strongly inhibited proliferation of lung adenocarcinoma A549 cells in tissue culture, and silencing PRMT5 expression in A549 cells also abolished growth of lung A549 xenografts in mice. In vitro and in vivo studies showed that the cell growth arrest induced by loss of PRMT5 expression was partially attributable to down-regulation of fibroblast growth factor receptor signalling. These results suggest that PRMT5 and its methyltransferase activity is essential for proliferation of lung cancer cells and may serve as a novel target for the treatment of lung cancer.     

内蒙古锡林河流域植物功能群组成及其水分利用效率的变化--依水分生态类群划分

依照植物水分生态类群,将锡林河流域主要植物种划分为6个植物功能群:呈生植物、中旱生植物、旱中生植物、中生植物、湿中生植物和湿生植物.沿土壤水分梯度,我们调查了8个植物群落的功能群组成及其δ13C值.结果表明:1)在水分状况不同的8个群落中,植物功能群的组成有很大差异.在较湿润生境中(沼泽化草甸和盐化草甸),湿中生和湿生植物成为优势种并构成地上生物量的主要部分;在干旱生境中(草甸草原、典型草原和退化草原),旱生和中旱生植物占绝对优势并构成群落生物量的90%以上;2)不同功能群δ13C值表现为:旱生植物(26.38‰)=中旱生植物(26.51‰)＞旱中生植物(-27.02‰)＞中生植物(-27.56‰)=湿中生和湿生植物(-27.80‰),表明随着不同水分生态类群所适应生境从干旱到湿润逐渐转变,植物的水分利用效率显著降低;3)在土壤水分状况不同的生境下,旱生植物始终维持相对较高的δ13C值和水分利用效率;而中旱生植物的δ13C值表现出较大的变化幅度,表明其对土壤水分的改变更敏感;4)旱生植物叶片脯氨酸含量最高;旱中生、中旱生和中生植物次之;湿中生和湿生植物脯氨酸含量最低.不同水分生态类群脯氨酸含量与其δ13C值和地上生物量呈显著正相关关系.     

Mining EST-Derived SSR Markers to Assess Genetic Diversity in Cassava (Manihot esculenta Crantz)

Cassava (Manihot esculenta Crantz) is a very important staple and industrial crop in tropical and subtropical regions of the world. The paucity of markers is a serious limitation in marker-assisted breeding. A total of 35,992 expressed sequence tags (ESTs) from cassava, which were clustered in 13,173 unigenes, were used in this study. A total of 1,889 microsatellites were identified, with an average density of one simple sequence repeats (SSRs) every 4.40 kb. Of the 1,058 designed EST-SSRs from cultivars SC06, TMS60444, and W14, 431 were polymorphic. Then, 31 randomly selected EST-SSRs from the 431 polymorphic EST-SSRs were used to evaluate the genetic diversity of 76 cassava accessions. A total of 93 alleles were identified, and the number detected for each EST-SSR ranged from one to four. Based on the 93 alleles, the 76 cassava accessions could be classified into six groups, and the genetic similarity coefficient ranged from 0.55 to 0.94. This study demonstrated the potential of EST-derived SSRs in cassava. The resources developed in this study enriched the available molecular markers for cassava.     

树木根系衰老研究的意义与现状

树木根系是树木重要的组成部分,具有养分和水分的吸收、传输和储存、树体的固定与支撑等重要的生理功能．在树木根系形成以后,常常遭遇到养分和水分胁迫,因此,其养分和水分的吸收功能尤其重要,在森林土壤中,养分和水分具有很大的时间和空间异质性,随着养分和水分在时间和空间上的变化,树木及时地主动调整其碳在根系中的分配,从而导致部分根系衰老或死亡,在林学上,树木根系衰老与养分和水分吸收关系密切,因而与树木生产力有直接的关系．在生态系统乃至全球尺度上,树木根系衰老影响碳循环和养分循环,因为根系对碳的消耗占树木通过光合作用所固定的碳的比例相当大,且含有丰富的养分．树木根系衰老受许多环境因子的影响,生物因子有真菌、细菌、病毒、土壤小型动物等,非生物因子有水分、温度、土壤养分、重金属等,这些因子对树木根系衰老的影响机制并不相同,尽管在树木根系衰老研究领域取得了长足的进步,提出了许多不同的假设,但仍有许多问题尚未解决,这些假设也需要更多的实验来验证,运用细胞学、生物化学、土壤科学、遗传学等多学科的交叉研究可进一步揭示根系衰老的本质。