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关键词： Ternary Complex   Quiescent Cell   Binary Complex   System Biology Markup Language   Origin Recognition Complex  

摘要： Background: The cell cycle is a complex process that allows eukaryotic cells to replicate chromosomal DNA and partition it into two daughter cells. A relevant regulatory step is in the G(0)/G(1) phase, a point called the restriction (R) point where intracellular and extracellular signals are monitored and integrated. Subcellular localization of cell cycle proteins is increasingly recognized as a major factor that regulates cell cycle transitions. Nevertheless, current mathematical models of the G(1)/S networks of mammalian cells do not consider this aspect. Hence, there is a need for a computational model that incorporates this regulatory aspect that has a relevant role in cancer, since altered localization of key cell cycle players, notably of inhibitors of cyclin-dependent kinases, has been reported to occur in neoplastic cells and to be linked to cancer aggressiveness. Results: The network of the model components involved in the G(1) to S transition process was identified through a literature and web-based data mining and the corresponding wiring diagram of the G(1) to S transition drawn with Cell Designer notation. The model has been implemented in Mathematica using Ordinary Differential Equations. Time-courses of level and of sub-cellular localization of key cell cycle players in mouse fibroblasts re-entering the cell cycle after serum starvation/re-feeding have been used to constrain network design and parameter determination. The model allows to recapitulate events from growth factor stimulation to the onset of S phase. The R point estimated by simulation is consistent with the R point experimentally determined. Conclusion: The major element of novelty of our model of the G(1) to S transition is the explicit modeling of cytoplasmic/nuclear shuttling of cyclins, cyclin-dependent kinases, their inhibitor and complexes. Sensitivity analysis of the network performance newly reveals that the biological effect brought about by Cki overexpression is strictly depende

关键词： 博尔纳病病毒   荧光定量巢式逆转录酶聚合酶链反应   病毒性脑炎   博尔纳病病毒   荧光定量PCR   牛   绵羊  

摘要： 目的检测宁夏地区病毒性脑炎患者外周血单个有核细胞(PBMCs)博尔纳病病毒(Borna Disease Virus, BDV)携带情况,分析该BDV与标准病毒株之间的同源性。探讨BDV感染性疾病与病毒性脑炎之间的关系,同时也为部分病毒性脑炎的病因学诊断及其防治提供实验依据。 方法采用荧光定量巢式逆转录酶聚合酶链反应(FQ-nRT-PCR)检测宁夏地区病毒性脑炎患者及正常人PBMCs有核细胞BDV p24基因片段,并对其中阳性扩增产物进行基因序列测定,然后采用BLAST软件以及DNAsist5.0软件对测序结果进行分析。 结果病毒性脑炎组样本BDV p24基因片段FQ-nRT-PCR阳性率为(10.17%)显著高于正常对照组(0%) (P<0.05)。病毒性脑炎患者检出的BDV p24基因片段的核苷酸序列与马的BDV标准病毒株H3915序列同源性为97.67%。与H1766株比较在3个位点出现一致性突变(nt1659 T→C,nt1668 A→G,nt1674 T→C,突变率为3.49%);与strain V株比较在4个位点出现一致性突变(nt1648 C→T, nt1658 G→A,nt1667 A→G,nt1673 T→C,突变率为4.65%),但编码的氨基酸相同。这些结果证实扩增所得目的基因片段确系BDV p24的相应片段。 结论宁夏地区病毒性脑炎患者中存在BDV感染,提示部分病毒性脑炎的发生可能与BDV感染有关。且该BDVp24扩增产物核苷酸序列与标准病毒株高度同源性,与马源的strain H3915同源性最高。 目的初步了解宁夏地区动物牛和绵羊BDV的隐性感染情况,对检测到的BDVp24基因阳性扩增片段进行核苷酸序列比对,探讨其与国外公认的标准病毒株strian He/80、strain V、strainV/FR、strain H3915和strain H1766的同源性。 方法采用Real-time nRT-PCR检测宁夏地区205例健康成年牛和268例健康绵羊PBMCs BDVp24基因片段,并对其中的阳性扩增产物进行基因序列测定,然后应用BLAST软件以及DNAsist 5.0软件对测序结果分析。 结果205例牛中3例阳性,268例绵羊中4例阳性,该BDVp24片段的核苷酸序列与标准株strain He/80同源性最高,为100%,与strain H3915同源性为97.67%,与strain H1766同源性为96.51%,与strain V和strainV/FR的同源性一致均为95.35%,但是它们编码的氨基酸相同。 结论宁夏地区动物牛和绵羊中存在动物源性BDV的隐性感染,该BDV p24核苷酸序列与strain He/80、strain H3915、strain H1766及strain V和strainV/FR具有高度同源性。

标准号: DIN ISO/TS 16649-3-2009

标准号: DIN ISO 16649-2-2009

摘要： This part of DIN ISO 16649 specifies a horizontal method for the enumeration of á-glucuronidase-positive Escherichia coli in products intended for human consumption or for the feeding of animals. It uses a colony-count technique at 44 ℃ on a solid medium containing a chromogenic ingredient for detection of the enzyme β-glucuronidase.

关键词： 饲料   培养基   定义   耐久性   食品   一般条件   导则   指南   说明书   实验室   微生物分析   微生物学   准备   生产   质量保证   规格试验   规范(验收)   储存   术语  

标准号: DIN ISO/TS 11133-1-2009

关键词： 饲料   生物试验   菌落计数技术   饮食   食品   实验室间试验   测量   测量不确定度   微生物分析   微生物学   定量的   定量分析   规范(验收)   试验室  

标准号: ISO/TS 19036 AMD 1-2009

标准号: DIN ISO 16649-1-2009

摘要： This part of DIN ISO 16649 specifies a horizontal method for the enumeration of beta-glucuronidase-positive Escherichia coli. It uses a colony-count technique after resuscitation using membranes and incubation at 44 ?C on a solid medium containing a chromogenis ingredient for detection of the enzymeá-glucuronidase.

关键词： 阿胶   鹿角胶   龟甲胶   地龙   羚羊角   鸡内金   穿山甲   蛋白质组学   激光解析/离子化-飞行时间质谱  

摘要： 背景激光解析/离子化-飞行时间质谱(SELDI-TOF-MS)技术为以蛋白质/肽为主要成分的中药蛋白质组学研究提供了重要的技术平台。 目的：对阿胶、鹿角胶、龟甲胶、地龙、羚羊角、鸡内金、穿山甲等7种传统中药水溶性蛋白/肽成分进行蛋白质组初步分析,建立中药蛋白质/肽相对分子质量指纹图。 方法：采用饱和硫酸胺沉淀,透析脱盐冻干法获得7种中药水溶性蛋白/肽；采用Ciphergen Biosystems Inc. ProteinChip (?) Biology System(美国PBSⅡ+)及配套的NP10芯片、激光解析/离子化-飞行时间质谱技术,分析Mr1500-13000区间蛋白质、肽分布及其相对分子质量。 结果：获得阿胶水溶性蛋白/肽相对分子质量峰38个,根据对比氨基酸相对分子质量分析,有意义蛋白/肽共计9个。鹿角胶水溶性蛋白质/肽共显示27个显著相对分子质量峰,约计16个有意义蛋白质/肽。龟甲胶水溶性蛋白/肽相对分子质量峰6个,约计6个有意义的蛋白/肽。地龙生干品和炮制品水溶性蛋白质/肽相对分子质量峰共计29个,其中生干品地龙17个有意义峰,炮制品地龙12个有意义峰。多个相邻蛋白质/肽峰之间相对分子质量相差一个氨基酸残基,并且生地龙与炮地龙有多组相对分子质量分别极为相近,推测可能为相同的肽段。羚羊角煎煮法和冷浸法获得水溶性蛋白/肽相对分子质量峰共计25个,其中煎煮法显示14个峰,冷浸法显示11个峰。对比分析这些肽段相对分子质量,部分差值与某些氨基酸残基相对分子质量相近。并且在煎煮和冷浸两种方法中显示出部分蛋白/肽相对分子质量相近,说明可能为同一肽段。鸡内金水溶性蛋白质/肽相对分子质量共显示63个肽相对分子质量峰,其中生干品计32个峰,炮制品31个峰。穿山甲炮制品水溶性蛋白质/肽相对分子质量共显示20个有意义相对分子质量峰。 结论：通过蛋白质芯片结合激光解析/离子化-飞行时间质谱技术,可以形成上述7种动物类中药蛋白质/肽成分相对分子质量指纹图,可作为这7种动物类中药数字化质控标准；并为进一步分离、纯化及验证这7种动物类中药功能相关活性蛋白质/肽组分提供可靠信息。

标准号: DIN ISO 21528-1-2009

摘要： This part of DIN ISO 21528 specifies a method for the detection and enumeration of Enterobacteriaceae by MPN technique with pre-enrichment.

摘要： Mammalian iron homeostasis is maintained by an intricate network of diverse proteins that constantly survey systemic iron levels and carefully regulate the uptake of iron from the diet. Control of this uptake is critically important because once iron is absorbed, mammals have no regulated mechanism for its removal. The portal through which iron enters the body is ferroportin, a multipass membrane protein expressed on the basolateral membrane of epithelial cells in the duodenum. The iron export function of ferroportin is primarily regulated by the serum peptide hormone hepcidin, which is secreted from the liver when systemic iron levels are high. Hepcidin acts as a negative regulator of iron uptake by binding to ferroportin at the cell surface and inducing its internalization and degradation. Genetic defects in ferroportin, hepcidin, or the proteins involved with sensing systemic iron levels lead to iron overload diseases known as hereditary hemochromatosis. Using the tools of biophysics and cell biology, we sought to study ferroportin and its interaction with hepcidin in order to better understand this critical bottleneck in iron uptake and how genetic defects within ferroportin might lead to disease. We developed the first protocols for the overexpression, detergent-solubilization, and purification of recombinant ferroportin. We determined that detergent-solubilized ferroportin is a monomer capable of binding hepcidin in vitro. We characterized the expression and subcellular localization of ferroportin in mammalian tissue culture and determined that both the amino- and carboxy-termini of ferroportin are cytosolic. We developed cell-based assays for the hepcidin-induced internalization of ferroportin and used these to characterize the route of internalization from the plasma membrane through early endosomes to degradative lysosomal compartments. Using live-cell imaging techniques, we showed that this internalization depended on intact microtubules. We expanded this