950 resultados para HERV


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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Der Längenpolymorphismus des C4-Gens beruht auf der An- oder Abwesenheit einer 6.4 kb langen Insertion im Intron 9. Es handelt sich dabei um einen eigenständigen bisher noch nicht beschriebenen Virus-Typ, der alle Sequenzmerkmale der Familie der humanen endogenen Retroviren (HERV) trägt und zu den HERV-K Viren gehört. Der Provirus wurde als HERV-K(C4) bezeichnet. Die Orientierung dieses retroviralen Elements ist entgegengesetzt zu der Transkriptionsrichtung des C4-Gens. Mittels RT-PCR, RNase Protection Assays und Northern-Blot Analysen konnte der Nachweis von HERV-K(C4)-Antisense mRNA-Transkripten in verschiedenen humanen Zellinien und Geweben erbracht werden. Die retroviralen Transkripte schlossen am 5'- und 3'-Ende Sequenzen des C4-Exon 9 und Exon 10 ein, so daß diese wahrscheinlich "readthrough" Transkripte darstellen, die durch einen 5' des LTR2 gelegenen Promotor initiiert oder im Zusammenhang mit der C4-Expression transkribiert und reguliert werden. Weiterhin konnten insgesamt 4 HERV-K(C4)-mRNA Spezies, einschließlich einer Vollängen-RNA detektiert werden. Die drei subgenomischen mRNAs werden vermutlich durch einfaches und mehrfaches Spleißen generiert. Die quantitative Analyse in verschiedenen humanen Zellinien ergab, daß HERV-K(C4) durchschnittlich mit einer Kopienanzahl zwischen ca.1 bis 100 Transkripten in einer Zelle vorkommt, so daß es sich um low abundance mRNAs handelt. Mittels eines Reportergen-System konnte eine Aktivität des LTR2-Promotors in der Sense-Orientierung des Retrovirus nachgewiesen werden, die nach Stimulation mit IFN- signifikant abnahm. Ein humanes Modell-Systems wurde etabliert, um die Theorie einer Antisense-Abwehr gegen exogene Retroviren in HepG2-Zellen zu überprüfen. Die Theorie basiert auf dem Nachweis von HERV-K(C4)-Antisense-Transkripten, die über eine Heteroduplexbildung mit der Sense-mRNA von verwandten, infektiösen Retroviren eine mögliche Blockierung deren Translation erwirken könnten. Es konnte eine signifikante Abnahme der retroviralen Expression von bis zu 45% nach steigenden Dosen an IFN- in HepG2-Zellen nachgewiesen werden. Der funktionell aktive 3'-LTR-Sense Promotor sowie der Nachweis von HERV-K(C4)-Antisense Transkripten sprechen für die bedeutende Rolle von HERV-K(C4) bei der Genregulation und Schutz gegen exogene Retroviren, wodurch eine Selektion stattgefunden hat.

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The human endogenous retrovirus K (HERV-K) env gene encodes envelope protein comprising surface (SU) and transmembrane (TM) domains. Having shown the exclusive expression of SU in human breast cancer and the stimulation of SU-specific immune responses in patients with breast cancer, our research here confirmed and extended the data by investigating the expression of HERV-K TM envelope domain and the induction of specific immune responses against TM in breast cancer patients. We found HERV-K TM mRNA and protein expression only in human breast cancer cells but not in normal controls. The specific immune responses against TM domain were induced in mice determined by enzyme-linked immunosorbent assay (ELISA) and IFN-γ enzyme-linked immunosorbent spot (ELISPOT) assay. Furthermore, ELISA detected higher titers of anti-HERV-K TM Env IgG antibodies in sera of breast cancer patients. In addition, the magnitude of the anti-HERV TM B cell response was correlated with the disease stage. Peripheral blood mononuclear cells (PBMCs) before and after in vitro stimulation (IVS) with HERV-K TM from patients with breast cancer as well as healthy controls were tested for T cell responses against HERV-K TM domain by ELISPOT assay. Breast cancer patients (n=21) had stronger HERV-K TM-specific cellular responses than healthy controls (n=12) (P < 0.05). These findings suggest, for the first time, that HERV-K TM expression was enhanced in human breast cancer cells and was able to induce specific B cell and T cell immune responses in breast cancer patients. This study provides support for HERV-K TM as a promising source of antigen for anti-tumor immunotherapy, prevention, diagnosis, and prognosis.

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Signatur des Originals: S 36/G02717

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Mode of access: Internet.

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In this paper, we present a microphone array beamforming approach to blind speech separation. Unlike previous beamforming approaches, our system does not require a-priori knowledge of the microphone placement and speaker location, making the system directly comparable other blind source separation methods which require no prior knowledge of recording conditions. Microphone location is automatically estimated using an assumed noise field model, and speaker locations are estimated using cross correlation based methods. The system is evaluated on the data provided for the PASCAL Speech Separation Challenge 2 (SSC2), achieving a word error rate of 58% on the evaluation set.

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Reducing complexity in Information Systems is an important topic in both research and industry. One strategy to deal with complexity is separation of concerns, which results in less complex, easily maintainable and more reusable systems. Separation of concerns can be addressed through the Aspect Oriented paradigm. Although this paradigm has been well researched in programming, it is still at the preliminary stage in the area of Business Process Management. While some efforts have been made to extend business process modelling with aspect oriented capability, it has not yet been investigated how aspect oriented business process models should be executed at runtime. In this paper, we propose a generic solution to support execution of aspect oriented business process models based on the principle behind dynamic weaving of aspects. This solution is formally specified using Coloured Petri Nets. The resulting formal specification serves as the blueprint to the implementation of a service module in the framework of a state-of-the-art Business Process Management System. Using this developed artefact, a case study is performed in which two simplified processes from real business in the domain of banking are modelled and executed in an aspect oriented manner. Through this case study, we also demonstrate that adoption of aspect oriented modularization increases the reusability while reducing the complexity of business process models in practice.

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This research examines three aspects of becoming a teacher, teacher identity formation in mathematics teacher education: the cognitive and affective aspect, the image of an ideal teacher directing the developmental process, and as an on-going process. The formation of emerging teacher identity was approached in a social psychological framework, in which individual development takes place in social interaction with the context through various experiences. Formation of teacher identity is seen as a dynamic, on-going developmental process, in which an individual intentionally aspires after the ideal image of being a teacher by developing his/her own competence as a teacher. The starting-point was that it is possible to examine formation of teacher identity through conceptualisation of observations that the individual and others have about teacher identity in different situations. The research uses the qualitative case study approach to formation of emerging teacher identity, the individual developmental process and the socially constructed image of an ideal mathematics teacher. Two student cases, John and Mary, and the collective case of teacher educators representing socially shared views of becoming and being a mathematics teacher are presented. The development of each student was examined based on three semi-structured interviews supplemented with written products. The data-gathering took place during the 2005 2006 academic year. The collective case about the ideal image provided during the programme was composed of separate case displays of each teacher educator, which were mainly based on semi-structured interviews in spring term 2006. The intentions and aims set for students were of special interest in the interviews with teacher educators. The interview data was analysed following the modified idea of analytic induction. The formation of teacher identity is elaborated through three themes emerging from theoretical considerations and the cases. First, the profile of one s present state as a teacher may be scrutinised through separate affective and cognitive aspects associated with the teaching profession. The differences between individuals arise through dif-ferent emphasis on these aspects. Similarly, the socially constructed image of an ideal teacher may be profiled through a combination of aspects associated with the teaching profession. Second, the ideal image directing the individual developmental process is the level at which individual and social processes meet. Third, formation of teacher identity is about becoming a teacher both in the eyes of the individual self as well as of others in the context. It is a challenge in academic mathematics teacher education to support the various cognitive and affective aspects associated with being a teacher in a way that being a professional and further development could have a coherent starting-point that an individual can internalise.

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Background: Betaretroviruses infect a wide range of species including primates, rodents, ruminants, and marsupials. They exist in both endogenous and exogenous forms and are implicated in animal diseases such as lung cancer in sheep, and in human disease, with members of the human endogenous retrovirus-K (HERV-K) group of endogenous betaretroviruses (βERVs) associated with human cancers and autoimmune diseases. To improve our understanding of betaretroviruses in an evolutionarily distinct host species, we characterized βERVs present in the genomes and transcriptomes of mega- and microbats, which are an important reservoir of emerging viruses.Results: A diverse range of full-length βERVs were discovered in mega- and microbat genomes and transcriptomes including the first identified intact endogenous retrovirus in a bat. Our analysis revealed that the genus Betaretrovirus can be divided into eight distinct sub-groups with evidence of cross-species transmission. Betaretroviruses are revealed to be a complex retrovirus group, within which one sub-group has evolved from complex to simple genomic organization through the acquisition of an env gene from the genus Gammaretrovirus. Molecular dating suggests that bats have contended with betaretroviral infections for over 30 million years.Conclusions: Our study reveals that a diverse range of betaretroviruses have circulated in bats for most of their evolutionary history, and cluster with extant betaretroviruses of divergent mammalian lineages suggesting that their distribution may be largely unrestricted by host species barriers. The presence of βERVs with the ability to transcribe active viral elements in a major animal reservoir for viral pathogens has potential implications for public health. © 2013 Hayward et al.; licensee BioMed Central Ltd.

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Contenido: Filosofía y vida / La Dirección – Ensayo sobre la acción / J. H. Nicolás O. P. – Reflexión acerca del principio de identidad / José María de Estrada – La evolución del patriotismo en occidente / Raymundo Paniker – Notas y comentarios -- Bibliografía

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本学位论文主要包括两部分的内容: 一是关于MAPK信号转导在天花粉蛋白(trichosanthin, TCS)抗人类免疫缺陷病毒-1(HIV-1)中的作用的研究。TCS是I型核糖体失活蛋白(RIP),分子量27Kd,可从传统的中期流产和抗绒癌中药栝楼根块茎(天花粉)中提纯获得。该蛋白具有抗HIV-1活性,但其机制尚不清楚。本文用JNK抑制剂CEP-11004,预处理宿主细胞,检测其对TCS抗HIV-1的影响。用以下两种方法检测病毒的复制:一是用ELISA方法检测细胞培养上清中p24抗原的水平,二是检测上清中病毒粒子的逆转录酶(RT)活性。结果显示,TCS剂量依赖性地抑制HIV-1在C8166细胞中的复制。在TCS实验浓度下,HIV-1的复制水平平均为68 ± 4%(p24抗原检测)和52 ± 4%(RT活性检测)。如果用0.4μM CEP-11004对C8166细胞预处理2小时,TCS似乎失去了抗HIV-1活性,HIV-1的复制水平分别恢复为101 ± 4%和101 ± 7%。但无论是p24抗原检测还是RT活性检测,当不含TCS时,CEP-11004预处理病毒宿主细胞,本身并不影响病毒粒子的复制。这说明CEP-11004能够拮抗TCS的抗病毒活性,或者说CEP-11004抑制的信号转导途径的某些信号分子,与TCS的抗HIV-1活性相关。Western Blot方法检测的结果也证明,TCS能够以时间依赖和剂量依赖的方式激活JNK激酶,0.4μM的CEP-11004能有效抑制JNK的磷酸化。因此,TCS与它激活MAPK信号转导途径有关。 二是关于人类内源性病毒HERV-W家族囊膜蛋白基因syncytin在白血病细胞中的表达的研究。该基因在人的胎盘组织中特异性表达,可能与合胞滋养层的形成有关。另外也少量表达于睾丸组织。本论文采用实时定量RT-PCR的方法证明,syncytin能够在白血病细胞系中表达。进一步的检测还表明,syncytin的mRNA也表达于白血病/淋巴瘤患者的外周血细胞,而不表达于作为对照的10名健康志愿者的血细胞。在15名不同类型的白血病/淋巴瘤患者中,有11名有syncytin的表达。细胞系的表达相对稳定,与C8166细胞系的表达量相比较,介于0.5-2.0倍之间;而在白血病患者外周血细胞中的表达则介于0.8-21.7倍不等。上述结果提示,syncytin可能与白血病的形成有关。

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人类内源性病毒(HERVs)是远古具有感染能力的逆转录病毒整合于人类基因组的遗迹, 大约占人类基因组的3%~8%,至少包括31个家族。它们通过不同的途径参与人类各种生理和病理活动的调节过程。大多数人类内源性病毒的基因, 由于基因的突变或部分缺失而失去了转录的能力。但有些基因依然保持完整的开放读码框, 能翻译成有功能的蛋白, 如HERV-W家族的囊膜蛋白合胞素基因, 可以被转录并翻译成有功能的蛋白质。目前合胞素的生理功能以及在各种病理过程中的作用机制仍然不清楚。国内对于合胞素的功能研究处于起步阶段,尚无商品化试剂,而且也没有合胞素抗体制备的报道。我们通过PCR扩增人合胞素基因编码区的DNA片段,将其克隆入原核表达质粒pET30a (+),转化大肠杆菌 BL21,诱导产生了合胞素-His融合蛋白。采用割胶回收的方法纯化目的蛋白, 免疫新西兰白兔, 制备了多克隆抗体。最后通过ELISA、Western-Blot和免疫组织化学等方法检测抗体的效价和特异性。我们成功表达并纯化了合胞素-His融合蛋白, SDS-PAGE分析表明融合蛋白主要以包涵体形式存在;ELISA法测定抗体效价为 1:10 000;Western-Blot和免疫组织化学结果显示所制备的抗体能特异性识别合胞素蛋白,为下一步研究合胞素的生物学功能奠定了基础。我们首次发现,合胞素能够在白血病和淋巴瘤细胞系中表达。利用我们制备的抗合胞素多克隆抗体,我们进一步检测该基因是否在白血病和淋巴瘤患者的外周血中表达,所有患者的外周血标本,均来自云南省有关医院。作为对照,我们还检测了20 名健康志愿者的外周血细胞。实验证明,合胞素基因(包括 mRNA 和蛋白)也在白血病患者的外周血细胞表达,而不表达于健康志愿者的血细胞。在30 名不同的白血病和淋巴瘤患者中,有22 名有合胞素的表达。荧光实时定量RT-PCR 的方法比较了合胞素在细胞系和白血病患者外周血中表达的相对定量,发现合胞素基因在所检测的5 种淋巴细胞系、3 种粒细胞系和1 种淋巴瘤细胞系中都有相对稳定的表达,表达水平与C8166 细胞系相比,介于0.5-2 倍之间。而在白血病患者中的表达则介于1.8-33.4 倍不等。我们的结果提示,合胞素可能与白血病的形成有关,因为该基因表达的囊膜蛋白具有很强的促细胞融合活性,含有具有免疫抑制活性的肽段,而且已发现某些与其类似的蛋白有致瘤能力。

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三取代杂多化合物的母体XM_9是由Keggin结构阴离子XM_(12)衍生而来.它有2种异构体:从XM_(12)中移出1个M_3O_(13)基团得B型异构体;从XM_(12)中的3个M_3O_(13)中各移出1个MO_6后得到A型异构体.Hervé等人曾指出α-和β-SiW_9均为B型结构,但Robert等在测定β-Na_9H(SiW_9O_(34))·23H_2O的晶体结构时发现,β-SiW_9为A型结构,α-SiW_9结构类型尚未定论,由于2种构型阴离子的配位能力及聚合能力不同,确定其结构类型及其变化情况是十分必要的,本文由α-SiW_9合成了α-K_3H_4[SiW_9A1_3(H_2O)_3O_(37)],用X射线衍射法测定了其晶体结构。