Cdk5 regulates accurate maturation of newborn granule cells in the adult hippocampus

Newborn granule cells become functionally integrated into the synaptic circuitry of the adult dentate gyrus after a morphological and electrophysiological maturation process. The molecular mechanisms by which immature neurons and the neurites extending from them find their appropriate position and target area remain largely unknown. Here we show that single-cell–specific knockdown of cyclin-dependent kinase 5 (cdk5) activity in newborn cells using a retrovirus-based strategy leads to aberrant growth of dendritic processes, which is associated with an altered migration pattern of newborn cells. Even though spine formation and maturation are reduced in cdk5-deficient cells, aberrant dendrites form ectopic synapses onto hilar neurons. These observations identify cdk5 to be critically involved in the maturation and dendrite extension of newborn neurons in the course of adult neurogenesis. The data presented here also suggest a mechanistic dissociation between accurate dendritic targeting and subsequent synapse formation.     

Continuously improving the practice of cardiology

Guidelines for the management of patients with cardiovascular disease are designed to assist cardiologists and other physicians in their practice. Surveys are conducted to assess whether guidelines are followed in practice. The results of surveys on acute coronary syndromes, coronary revascularisation, secondary prevention, valvular heart disease and heart failure are presented. Comparing surveys conducted between 1995 and 2002, a gradual improvement in use of secondary preventive therapy is observed. Nevertheless, important deviations from established guidelines are noted, with a significant variation among different hospitals in the Netherlands and in other European countries. Measures for further improvement of clinical practice include more rapid treatment of patients with evolving myocardial infarction, more frequent use of clopidogrel and glycoprotein IIb/IIIa receptor blockers in patients with acute coronary syndromes, more frequent use of β-blockers in patients with heart failure and more intense measures to encourage patients to stop smoking. Targets for the proportion of patients who might receive specific therapies are presented.     

犬MC1R基因R306ter与毛色性状相关性研究

目的　分析犬MC1R基因中R30 6ter位点多态性与犬毛色表型的相关性 ,为遗传育种 ,培育出更加优良的实验用犬奠定基础。方法　采用PCR SSCP技术 ,对MC1R基因R30 6ter位点进行基因多态性检测 ,分析位点多态性与毛色性状之间的相关性 ,并对该位点进行克隆测序。结果　PCR SSCP分析结果表明 ,R30 6ter位点序列具有多态性 ,表现为C、D二个等位基因和CC、CD及DD三种基因型。对R30 6ter多态性片段克隆测序发现 ,MC1R基因在编码第 30 6位氨基酸的密码子处存在一个由CGA到TGA的终止突变。结论　经统计分析结果表明在杂种犬中MC1R基因多态性与毛色性状不存在显著的相关性 ,这可能是由于外科手术学教学用犬是杂种犬 ,其遗传背景不同所致。由于MC1R基因的R30 6ter位点内存在碱基变异 ,因此在杂种犬中表现出明显的PCR SSCP多态性     

吸氧预处理对大鼠脑缺血再灌注损伤的保护作用

目的探讨吸氧预处理对大鼠脑缺血再灌注损伤的保护作用。方法通过大鼠局灶脑缺血再灌注损伤模型,采用SOD、MDA测定、电镜及神经行为学检查的方法,观察吸氧预处理对大鼠脑缺血再灌注损伤后SOD、MDA、神经行为学评分及脑组织病理变化。结果吸氧预处理组SOD活力高于对照组(P<0.05),MDA含量、神经行为学评分均低于对照组(P<0.05),脑组织超微结构损伤均减轻。结论吸氧预处理对大鼠脑缺血再灌注损伤有保护作用。     

CCR2-64Ⅰ在中国南方14个少数民族群体中的分布

为调查HIV-1感染相关等位基因CCR2-64Ⅰ在我国南方14个少数民族群体的频率和多态性分布, 从上述人群外周血中抽提基因组DNA, 采用PCR和PCR-RFLP等方法进行基因分型。在791例调查对象中, 636例是野生纯合子基因型, 104例为杂合子基因型, 51例为突变纯合子基因型。上述各群体等位基因型的分布符合Hardy-Weinberg平衡。14个民族群体的平均突变基因频率为13.6％, 等位基因频率范围分布在1.6％~30.3％之间, 14个民族群体之间突变基因频率具有显著差异(P<0.05)。广西壮族群体CCR2-64Ⅰ突变基因频率最低, 为1.6％, 云南的六库傈僳族频率最高, 为30.3％。12个群体的突变基因频率均低于中国汉族健康群体, 南方3个少数民族群体基因突变频率显著低于西南11个少数民族群体, 该突变基因在艾滋病发病过程中的影响值得进一步深入研究。     

羊抗人IgG的纯化及其在抗—HCV检测中的应用

单独或联合应用辛酸沉淀、饱和硫酸铵沉淀、阴离子交换等方法对羊抗人IgG进行纯化,对纯化前后抗体的纯度和免疫学活性进行比较,并与辣根过氧化物酶连接,作为二抗用于抗－HCV的ELISA检测。结果表明,不同方法纯化的抗体其纯度和免疫学活性具有一定程度的差别,其中经辛酸＋饱和硫酸铵沉淀纯化的抗体为最佳,凝胶扫描纯度为98．05％,比活性近1800,为纯化前的6．8倍。用痞根过氧化物酶标记后,作为酶标二抗检测HCV阴性和阳性标准血清各40份,阴性符合率为97．5％,阳性符合率为95％,可用于抗－HCV的ELISA检测。     

真正柑橘果树类植物基于AFLP分子标记的分类与进化研究

用AFLP分子标记技术对芸香科Rutaceae柑橘亚科Aurantioideae真正柑橘果树类(the True Citrus Fruit Trees Group) 6属植物的59个生物类型以及九里香Murraya exotica L.、蚝壳刺Severinia buxifolia Tenore和酒饼簕Atalantia buxifolia Oliv.进行了分析。从64对引物组合中筛选出15对分辨率好的引物对全部材料进行了扩增, 共获得312条带, 其中多态型带305条, 多态位点达97.8%。利用PAUP软件构建了全部材料基于AFLP数据的UPGMA距离树。结果表明, AFLP证据支持基于形态特征建立的真正柑橘果树群以及群内各属的划分, 只是金柑属Fortunella Swingle作为一个独立的分支嵌于柑橘属Citrus L.内。对于柑橘属, 我们的分子证据支持Swingle关于亚属的划分以及Scora等关于C. medica、C. grandis和C. reticulata是真正柑橘亚属subgen. Eucitrus三个基本种的观点。AFLP分子证据显示宜昌橙C. ichangensis Swingle位于真正柑橘亚属中, 与香橙C. junos Sieb. ex Tanaka的亲缘关系最近, 而与大翼橙亚属subgen. Papeda中马蜂柑C. hystrix DC.相隔甚远。另外, 莽山野橘C. mangshanensis S. W. He &; G. F. Liu在系统树上居于宽皮柑橘类的基部。最后, 对真正柑橘果树群6属植物间以及柑橘属各主要类型(种)的进化关系进行了详细的讨论。     

Phospholipase Cgamma2 mediates RANKL-stimulated lymph node organogenesis and osteoclastogenesis

Phospholipase Cgamma2 (PLCgamma2) is an important signaling effector of multiple receptors in the immune system. Here we show that PLCgamma2-deficient mice displayed impaired lymph node organogenesis but normal splenic structure and Peyer's patches. Receptor activator of NF-kappaB ligand (RANKL) is a tumor necrosis factor family cytokine and is essential for lymph node organogenesis. Importantly, PLCgamma2 deficiency severely impaired RANKL signaling, resulting in marked reduction of RANKL-induced activation of MAPKs, p38 and JNK, but not ERK. The lack of PLCgamma2 markedly diminished RANKL-induced activation of NF-kappaB, AP-1, and NFATc1. Moreover, PLCgamma2 deficiency impaired RANKL-mediated biological function, leading to failure of the PLCgamma2-deficient bone marrow macrophage precursors to differentiate into osteoclasts after RANKL stimulation. Re-introduction of PLCgamma2 but not PLCgamma1 restores RANKL-mediated osteoclast differentiation of PLCgamma2-deficient bone marrow-derived monocyte/macrophage. Taken together, PLCgamma2 is essential for RANK signaling, and its deficiency leads to defective lymph node organogenesis and osteoclast differentiation.     

奶山羊β-乳球蛋白基因5'、3'调控区的克隆和序列分析

目的:克隆奶山羊β-乳球蛋白(BLG)基因5'、3'调控区,并对其进行序列分析.方法:从徐淮奶山羊组织中提取基因组DNA,采用高保真长模板PCR法克隆得到奶山羊BLG基因4.2 kb的5'调控区和1.8 kb的3'调控区;将纯化后的PCR产物克隆到pGEM-T Easy载体中,经酶切鉴定和序列测定验证克隆的正确性.结果:部分序列分析表明,奶山羊BLG基因5'区与GenBank中登录的山羊和绵羊BLG基因5'区的同源性分别为100%和95%,3'区的同源性分别为99%和93%;克隆得到的奶山羊BLG基因调控区与山羊BLG伪基因显著不同,二者5'区和3'区的同源性分别为83%和88%.结论:克隆得到的奶山羊BLG基因调控区可用于构建乳腺特异性表达载体,用于外源基因在转基因动物乳腺中的高效表达.     

羊草草地生长季放牧山羊采食量和食性选择

在松嫩平原羊草草地,通过控制放牧实验对山羊的时限采食量和食性选择进行了研究。结果表明：（1）5－9月份,山羊的时限（1h）采食量平均为0.42kg干物质,其季节动态为5月份最低,随季节推移不断增大,8月份达到最大,9月份又有所减小;时限采食量基本上随放牧率减小而增大,但在最低放牧率小区有所减小。（2）山羊的食性选择随季节推移和放牧率不同而变化。（3）山羊对20－25cm高度草层的选择性最高;各高度草层的食性选择指数随季节推移和放牧率不同而变化;山羊对不同植物的高度选择性存在差异,但高度选择指数的最大值都在15－30cm范围内。