血清胱抑素C对慢性心衰患者早期肾功能损害的诊断价值

目的探讨血清胱抑素C(Cys-C)对慢性心力衰竭患者早期肾功能损害的诊断价值。方法选择慢性心力衰竭(CHF)患者55例(无原发肾脏损害)设为A组,并按NYHA心功能分级标准(Ⅰ～Ⅳ级)将其分为不同亚组;选择无CHF的心脏病患者40例设为B组;另选32例健康志愿者作为空白对照设为C组。测定各组血清Cys-C、血清肌酐(SCr)、脑利钠肽(pro-BNP)、24h尿蛋白(UMA)和β2微球蛋白(β2-MG)水平,测量左室射血分数(LVEF),进行统计学分析。结果 A组与B、C组比较,CHF患者血Cys-C浓度明显高于对照组(P<0.01),其中心功能Ⅲ、Ⅳ级的血清浓度高于Ⅰ～Ⅱ级(P<0.05);血Cys-C与pro-BNP、UMA呈显著正相关(r=0.613,P=0.014,r=0.56,P=0.029),与LVEF呈负相关(r=-0.55,P=0.038)。与SCr不相关(P=0.61)。结论血清Cys-C水平可能是反映心衰严重程度的标志之一。其对慢性心衰患者肾功能的评估优于SCr,测定血清Cys-C浓度对发现心力衰竭患者早期肾损害及评估预后具有一定临床意义。     

黎药光叶巴豆枝叶的化学成分分析

为研究光叶巴豆枝叶的化学成分,笔者采用硅胶柱色谱、Sephadex LH-20、半制备高效液相色谱等多种色谱技术进行化合物的分离纯化,通过化合物的波谱数据和理化性质鉴定其结构.从光叶巴豆枝叶95％乙醇提取物中分离得到12个化合物,分别鉴定为:(3S,5R,6S,7E,9R)-3,6-dihydroxy-5,6-dihy...     

BAX and BAK regulation of endoplasmic reticulum Ca2+: a control point for apoptosis

BAX and BAK are "multidomain" proapoptotic proteins that initiate mitochondrial dysfunction but also localize to the endoplasmic reticulum (ER). Mouse embryonic fibroblasts deficient for BAX and BAK (DKO cells) were found to have a reduced resting concentration of calcium in the ER ([Ca2+]er) that results in decreased uptake of Ca2+ by mitochondria after Ca2+ release from the ER. Expression of SERCA (sarcoplasmic-endoplasmic reticulum Ca2+ adenosine triphosphatase) corrected [Ca2+]er and mitochondrial Ca2+ uptake in DKO cells, restoring apoptotic death in response to agents that release Ca2+ from intracellular stores (such as arachidonic acid, C2-ceramide, and oxidative stress). In contrast, targeting of BAX to mitochondria selectively restored apoptosis to "BH3-only" signals. A third set of stimuli, including many intrinsic signals, required both ER-released Ca2+ and the presence of mitochondrial BAX or BAK to fully restore apoptosis. Thus, BAX and BAK operate in both the ER and mitochondria as an essential gateway for selected apoptotic signals.     

云芝化学成分研究

 从真菌云芝子实体中分离鉴定了6个化合物和1个混合物,分别为：(22E,24R)-ergosta-7,22-dien-3β-ol（1）、 (22E, 24R)-ergosta-6,22-dien-3β,5α,8α-triol（2）、5α,6α-epoxy-(22E,24R)-ergosta-8,22-dien-3β,7α-diol（3）、二十四碳酸（4）、二十六碳酸（5）和α,α-trehalose（6）;混合物可推测主要由russulamide（7）、ascolipid C（8）、ascolipid D（9）组成。除化合物1外,其余化合物均为该种首次分离得到。     

Phosphoryl transfer and calcium ion occlusion in the calcium pump

A tight coupling between adenosine triphosphate (ATP) hydrolysis and vectorial ion transport has to be maintained by ATP-consuming ion pumps. We report two crystal structures of Ca2+-bound sarco(endo)plasmic reticulum Ca2+-adenosine triphosphatase (SERCA) at 2.6 and 2.9 angstrom resolution in complex with (i) a nonhydrolyzable ATP analog [adenosine (beta-gamma methylene)-triphosphate] and (ii) adenosine diphosphate plus aluminum fluoride. SERCA reacts with ATP by an associative mechanism mediated by two Mg2+ ions to form an aspartyl-phosphorylated intermediate state (Ca2-E1 approximately P). The conformational changes that accompany the reaction with ATP pull the transmembrane helices 1 and 2 and close a cytosolic entrance for Ca2+, thereby preventing backflow before Ca2+ is released on the other side of the membrane.     

基于火焰原子吸收光谱法的斑纹芦荟中微量矿物元素含量测定

［目的］采用火焰原子吸收光谱法同时测定可食用斑纹芦荟［Aloe vera L. var. chinensis （Haw.） Baker］中微量矿物元素Ca、Mg、Fe、Zn、Na、K离子的含量。［方法］采用5∶〖KG-＊2/3〗1的HNO3 H2O2体系作为消化液湿法消化样品,对各元素含量进行测定。［结果］斑纹芦荟中各微量矿物元素的线性回归方程为Ca：A=0.023 99C＋0.006 6（R=0.999 7）,Mg：A=0.334 50C＋0.007 5（R=0.999 9）,Fe：A=0.022 63C＋0.001 2（R=0.999 4）,Zn：A=0.369 70C＋0.001 6（R=0.999 2）,Na：A=0.044 87C＋0.001 4（R=0.998 8）,K：A=0.312 70C＋0.029 9（R=0.999 2）;回收率在97.6%-103.0%,相对标准偏差（RSD）均小于2.49%（n=8）。斑纹芦荟中微量矿物元素Ca、Mg、Na、K的含量较高,均高于0.20 mg/g,其中,Ca的含量最高达2.63 mg/g;Zn、Fe的含量较低,分别为4.92、6.60 μg/g。［结论］试验中的测定方法准确、可靠,测定结果令人满意。该研究可为斑纹芦荟在医疗和食品中的应用提供指导。     

PCSK9基因D374Y突变体转基因猪的制备与分析

【目的】前蛋白转化酶枯草溶菌素9(proprotein convertase subtilisin/Kexin type 9,PCSK9)基因是人类高胆固醇血症(autosomal dominant hypercholesterolemia,ADH)的主效基因之一,其获得型突变与人类家族性高胆固醇血症有直接的关系。PCSK9-D374Y突变体对低密度脂蛋白受体(low density lipoprotein receptor,LDLR)的降解能力比野生型蛋白强十倍,增加了患高胆固醇血症的风险,从而加速动脉粥样硬化的进程。猪心血管系统和血脂代谢方面与人类非常相近,成为研究动脉粥样硬化疾病的理想模型之一。然而自然发病的猪缺乏,且诱导病征发生缓慢。因此拟利用体细胞克隆技术制备PCSK9获得型突变体转基因猪,以模拟动脉血管的病理学变化,加速发病进程,为动脉粥样硬化的研究提供理想的动物模型。【方法】研究使用人PCSK9基因D374Y突变体载体,用电转染的方法将其整合到五指山小型猪近交系胎儿成纤维细胞中,并通过体细胞核移植技术获得了人PCSK9基因D374Y突变体转基因猪个体。通过Southern-blot、实时荧光定量PCR、Western-blot等方法,分别从DNA、RNA、蛋白的水平检测了人PCSK9基因在转基因猪肝脏中的整合表达情况。同时,通过组织化学染色与H.E.染色的方法对转基因猪进行了组织学检测。【结果】转基因阳性细胞集落在药筛的第3天开始出现,至第7天形成较大的单克隆点,且PCR检测结果显示扩增产物可以拼接为完整片段,说明外源片段在基因组中具有完整性;将筛选得到的阳性细胞作为体细胞克隆的供体细胞,通过体细胞核移植技术获得了转基因猪个体。PCR及Southern-blot检测结果显示,D374Y-PCSK9基因可以完整的插入猪的基因组中,且有串联重复现象;RT-PCR和QPCR检测结果表明,人PCSK9基因能在猪肝脏内正常转录且不影响猪内源性PCSK9基因的转录,且在其它内脏器官,如心、脾、肺、肾也能检测人PCSK9基因的表达,而猪内源性PCSK9基因在这些组织中表达量很低;Western-blot检测结果与RNA水平的检测类似。这些结果说明人D374Y-PCSK9基因成功整合到猪基因猪中,且能够正常转录与翻译。通过组织化学染色发现,与野生型猪肝脏相比,克隆猪肝脏中LDLR蛋白水平极显著低于野生型。另外,对克隆猪进行H.E.染色后发现其肝脏组织有明显的病理学变化,该结果说明,LDLR水平的急剧下降有可能是导致肝脏病变的原因。【结论】成功获得了人PCSK9基因D374Y突变体的克隆猪;与野生型猪肝脏相比,克隆猪肝脏中LDLR水平显著降低,并且克隆猪肝脏发生了明显病变。     

一种三角帆蚌肌浆网Ca2+-ATP酶基因cDNA的全长克隆与表达分析

采用RACE技术,从三角帆蚌(Hyriopsis cumingii)鳃组织中成功克隆得到一种肌浆网Ca²⁺-ATP酶(sarco/endoplasmic reticulum calcium ATPase,SERCA)基因的全长cDNA序列,共3 326 bp,包含201-bp 5’-UTR区域、3 060-bp编码框(ORF)和65-bp 3’-UTR。ORF共编码1 019个氨基酸,预测无信号肽。该基因氨基酸序列呈现出典型的Ca²⁺-ATP酶特征,由Cation_ATPase_N、E1-E2_ATPase、Hydrolase、Cation_ATPase_C四种类型结构域组成,其内含SERCAs的常见结构组成包括磷酸化区域、异硫氰酸荧光素位点、FSBA结合位点、受磷蛋白结合区以及毒胡萝卜素位点。分析显示,该基因序列高度保守且与海洋软体动物具有最高同源性。荧光定量PCR检测,该基因在三角帆蚌外套膜、斧足、鳃、肝胰腺、性腺等5个组织中均有表达,且在鳃、外套膜、肝胰腺组织中表达较高。不同Ca²⁺浓度处理试验的结果表明,随水体中Ca²⁺浓度逐渐升高,该基因在外套膜中的表达水平呈先下降后上升趋势,并在Ca²⁺浓度为60 mg·L^-1时达到最低值,80 mg·L^-1时达到最高值。同时在60 mg·L^-1 Ca²⁺浓度条件下,外套膜中SERCA基因的表达量随时间推移先上升,并于48 h时达到最高,而后逐渐下降。上述结果为进一步深入研究SERCA基因的功能及其调控机理奠定了基础。     

Dynamics of a Second-Order Phase Transition: P macr; to I1 Phase Transition in Anorthite, CaAl2Si2O8

Electron microscopic study of the reversible P1 to I1 phase transition in anorthite (transition temperature T(c) = 516 Kelvin) shows that the antiphase boundaries (APBs) with the displacement vector R = 1/2[111] become unstable at T(c), and numerous small APB loops are formed. These interfaces are highly mobile, and their vibration frequency increases strongly with temperature. These observations suggest that close to T(c), breathing-motion-type lattice vibrations of the framework cause the two different configurations around the calcium atoms, which are related by a translation of R approximately 1/2[111], to interchange dynamically through an intermediate I1 configuration. The high-temperature I1 structure is interpreted as a statistical-dynamic average of highly mobile antiphase domains of primitive anorthite.     

Suppression of human colorectal carcinoma cell growth by wild-type p53

Mutations of the p53 gene occur commonly in colorectal carcinomas and the wild-type p53 allele is often concomitantly deleted. These findings suggest that the wild-type gene may act as a suppressor of colorectal carcinoma cell growth. To test this hypothesis, wild-type or mutant human p53 genes were transfected into human colorectal carcinoma cell lines. Cells transfected with the wild-type gene formed colonies five- to tenfold less efficiently than those transfected with a mutant p53 gene. In those colonies that did form after wild-type gene transfection, the p53 sequences were found to be deleted or rearranged, or both, and no exogenous p53 messenger RNA expression was observed. In contrast, transfection with the wild-type gene had no apparent effect on the growth of epithelial cells derived from a benign colorectal tumor that had only wild-type p53 alleles. Immunocytochemical techniques demonstrated that carcinoma cells expressing the wild-type gene did not progress through the cell cycle, as evidenced by their failure to incorporate thymidine into DNA. These studies show that the wild-type gene can specifically suppress the growth of human colorectal carcinoma cells in vitro and that an in vivo-derived mutation resulting in a single conservative amino acid substitution in the p53 gene product abrogates this suppressive ability.     

Juvenile hormone action mediated in male accessory glands of Drosophila by calcium and kinase C

In an in vitro system for the Drosophila melanogaster male accessory gland, it was found that 10(-9)M juvenile hormone III could accurately mimic the copulation-induced response of increased protein synthesis in glands from virgin flies. Stimulation by this hormone required calcium in the medium. Experiments with tumor-promoting phorbol esters indicated that activation of protein kinase C can also cause the glands to increase protein synthesis. Stimulation of protein synthesis by juvenile hormone did not occur in mutants deficient in kinase C activity. These results suggest a membrane-protein-mediated effect of juvenile hormone that involves calcium and kinase C.     

绵羊GDF9基因FecTT突变检测

FecTT是冰岛Thoka绵羊GDF9基因外显子2编码区1279位发生的A→C突变(A1279C),导致编码GDF9蛋白C末端成熟肽第109位丝氨酸改变为精氨酸(S109R),该突变纯合子母羊不育,杂合子母羊产羔数比野生型多0.6只。本研究采用PCR-RFLP方法分析了GDF9基因FecTT突变在小尾寒羊、洼地绵羊、湖羊、考力代、白萨福克、黑萨福克、东弗里生、杜泊绵羊、特克塞尔、多赛特和中国美利奴11个绵羊品种中的分布。结果表明在11个绵羊品种中都没有检测到GDF9基因的FecTT突变,提示GDF9基因影响Thoka绵羊高繁殖力的FecTT突变对以上11个绵羊品种的繁殖力均没有显著影响。     

Protection from cardiac arrhythmia through ryanodine receptor-stabilizing protein calstabin2

Ventricular arrhythmias can cause sudden cardiac death (SCD) in patients with normal hearts and in those with underlying disease such as heart failure. In animals with heart failure and in patients with inherited forms of exercise-induced SCD, depletion of the channel-stabilizing protein calstabin2 (FKBP12.6) from the ryanodine receptor-calcium release channel (RyR2) complex causes an intracellular Ca2+ leak that can trigger fatal cardiac arrhythmias. A derivative of 1,4-benzothiazepine (JTV519) increased the affinity of calstabin2 for RyR2, which stabilized the closed state of RyR2 and prevented the Ca2+ leak that triggers arrhythmias. Thus, enhancing the binding of calstabin2 to RyR2 may be a therapeutic strategy for common ventricular arrhythmias.     

Soil Aggregate Stability and Aggregate-Associated Carbon Under Different Tillage Systems in the North China Plain

The inlfuences of tillage systems on soil carbon （C） stocks have been studied extensively, but the distribution of soil C within aggregate fractions is not well understood. The objective of this study was to determine the inlfuences of various tillage systems on soil aggregation and aggregate-associated C under wheat （Triticum aestivum L.） and corn （Zea mays L.） double cropping systems in the North China Plain. The experiment was established in 2001, including four treatments：moldboard plow （MP） with residue （MP＋R） and without residue （MP-R）, rotary tillage with residue （RT）, and no-till with residue （NT）. In 2007 soil samples were collected from the 0-5, 5-10, and 10-20 cm depths, and were separated into four aggregate-size classes （〉2 000, 250-2 000, 53-250, and〈53 μm） by wet-sieving method. Aggregate-associated C was determined, and the relationships between total soil C concentration and aggregation-size fractions were examined. The results showed that NT and RT treatments signiifcantly increased the proportion of macroaggregate fractions （〉2 000 and 250-2 000 μm） compared with the MP-R and MP＋R treatments. Averaged across all depths, mean weight diameters of aggregates （MWD） in NT and RT were 47 and 20% higher than that in MP＋R. The concentration of bulk soil organic C was positively correlated with MWD （r=0.98; P=0.024） and macroaggregate fraction （r=0.96; P=0.036） in the 0-5 cm depth. In the 0-20 cm depth, comparing with MP＋R, total C occluded in the〉2 000 μm fraction was increased by 9 and 6%under NT and RT, respectively. We conclude that adoption of conservation tillage system, especially no-till, can increase soil macro-aggregation and total C accumulation in macroaggregates, which may improve soil C sequestration in the intensive agricultural region of the North China Plain.     

不同H9N2亚型鸭流感病毒NS1基因克隆和功能进化分析

禽流感病毒（AIV）在高免疫压力情况下会发生变异而逃避免疫系统的监视。其NS1蛋白共有230个氨基酸,其中前73个氨基酸残基以二聚体形式存在,包含了所有RNA的结合活性。NS1的氨基端1—73位是mRNA的结合区,氨基端1—100位是双股RNA依赖性蛋白激酶（PKR）的结合区。PKR抗病毒作用机制如下：病毒侵染宿主细胞时,在宿主干扰素的诱导下,双股RNA与PKR结合,同时真核翻译启动子α亚单位发生磷酸化,导致PKR的激活。激活的PKR能同时抑制宿主细胞和病毒mRNA的翻译,从而最终抑制入侵病毒在细胞中的有效繁殖和扩散。     

Signaling of rat Frizzled-2 through phosphodiesterase and cyclic GMP

The Frizzled-2 receptor (Rfz2) from rat binds Wnt proteins and can signal by activating calcium release from intracellular stores. We show that wild-type Rfz2 and a chimeric receptor consisting of the extracellular and transmembrane portions of the beta2-adrenergic receptor with cytoplasmic domains of Rfz2 also signaled through modulation of cyclic guanosine 3',5'-monophosphate (cGMP). Activation of either receptor led to a decline in the intracellular concentration of cGMP, a process that was inhibited in cells treated with pertussis toxin, reduced by suppression of the expression of the heterotrimeric GTP-binding protein (G protein) transducin, and suppressed through inhibition of cGMP-specific phosphodiesterase (PDE) activity. Moreover, PDE inhibitors blocked Rfz2-induced calcium transients in zebrafish embryos. Thus, Frizzled-2 appears to couple to PDEs and calcium transients through G proteins.     

The snoRNA HBII-52 regulates alternative splicing of the serotonin receptor 2C

The Prader-Willi syndrome is a congenital disease that is caused by the loss of paternal gene expression from a maternally imprinted region on chromosome 15. This region contains a small nucleolar RNA (snoRNA), HBII-52, that exhibits sequence complementarity to the alternatively spliced exon Vb of the serotonin receptor 5-HT(2C)R. We found that HBII-52 regulates alternative splicing of 5-HT(2C)R by binding to a silencing element in exon Vb. Prader-Willi syndrome patients do not express HBII-52. They have different 5-HT(2C)R messenger RNA (mRNA) isoforms than healthy individuals. Our results show that a snoRNA regulates the processing of an mRNA expressed from a gene located on a different chromosome, and the results indicate that a defect in pre-mRNA processing contributes to the Prader-Willi syndrome.     

The radical site in chlamydial ribonucleotide reductase defines a new R2 subclass

Ribonucleotide reductase (RNR) synthesizes the deoxyribonucleotides for DNA synthesis. The R2 protein of normal class I ribonucleotide reductases contains a diiron site that produces a stable tyrosyl free radical, essential for enzymatic activity. Structural and electron paramagnetic resonance studies of R2 from Chlamydia trachomatis reveal a protein lacking a tyrosyl radical site. Instead, the protein yields an iron-coupled radical upon reconstitution. The coordinating structure of the diiron site is similar to that of diiron oxidases/monoxygenases and supports a role for this radical in the RNR mechanism. The specific ligand pattern in the C. trachomatis R2 metal site characterizes a new group of R2 proteins that so far has been found in eight organisms, three of which are human pathogens.     

TDR测定淡栗钙土水分的标定

本实验以荒漠草原2个不同种类的土壤为研究材料,使用TRIME - IPH型TDR测定不同放牧强下的土壤含水量,并以烘干法测定值为真实值对其进行了标定.结果表明:室内标标定中的TRIME - IPH测值与烘干法测值都具有良好的相关性,沙土中的相关系数(R2=0.983 9)略低于壤土(R2=0.986 0),而平均相对偏差(16.4％)大干壤土(12.3％).校正方程为TDR校正值=0.998 0烘干法测定值+2.3900.在野外标定中,不同放牧强度下TRIME - IPH测值与烘干法测值的相关性也很好,总体校正的相关系数为0.774 3.本研究结果证实,TRIME - IPH完全能够胜任该地区土壤水分动态特征及变化趋势的研究工作.     

基于SVRM的不同氨、碱化处理玉米秸秆粗蛋白定量分析模型研究

文章采用近红外光谱分析方法验证不同条件下氨化和碱化处理玉米秸秆粗蛋白含量测定效果。选择不同超声条件对玉米秸秆样品前处理,获取54种样品,粗蛋白含量为2.535 6%~6.854 7%,依据X-Y残差法剔除29、30、38、51号异常样本,交互验证决定系数R2C由0.679升至0.840,将剩余50个样品划分为校正集(40samples)及验证集(10 samples),选用OSC方法对光谱去噪处理,对比平滑处理(windowsize 15),R2C由0.827升至0.865,选取波段9 781~1 093 cm-1作为特征波段,对比SVRM、PCR及PLS 3种粗蛋白定量分析模型,选取SVRM(C=0.01,Gamma=100)为最佳模型,校正集决定系数R2C为0.833,RMSEC为0.389,验证集决定系数R2P为0.914,RMSEP为0.296。结果表明,近红外光谱分析方法测定玉米秸秆氨化、碱化处理后粗蛋白含量可行。