949 resultados para Motifs of marvellous transformation
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Glioblastoma multiforme (GBM) is an aggressive, high grade brain tumor. Microarray studies have shown a subset of GBMs with a mesenchymal gene signature. This subset is associated with poor clinical outcome and resistance to treatment. To establish the molecular drivers of this mesenchymal transition, we correlated transcription factor expression to the mesenchymal signature and identified transcriptional co-activator with PDZ-binding motif (TAZ) to be highly associated with the mesenchymal shift. High TAZ expression correlated with worse clinical outcome and higher grade. These data led to the hypothesis that TAZ is critical to the mesenchymal transition and aggressive clinical behavior seen in GBM. We investigated the expression of TAZ, its binding partner TEAD, and the mesenchymal marker FN1 in human gliomas. Western analyses demonstrated increased expression of TAZ, TEAD4, and FN1 in GBM relative to lower grade gliomas. We also identified CpG islands in the TAZ promoter that are methylated in most lower grade gliomas, but not in GBMs. TAZ-methylated glioma stem cell (GSC) lines treated with a demethylation agent showed an increase in mRNA and protein TAZ expression; therefore, methylation may be another novel way TAZ is regulated since TAZ is epigenetically silenced in tumors with a better clinical outcome. To further characterize the role of TAZ in gliomagenesis, we stably silenced or over-expressed TAZ in GSCs. Silencing of TAZ decreased invasion, self-renewal, mesenchymal protein expression, and tumor-initiating capacity. Over-expression of TAZ led to an increase in invasion, mesenchymal protein expression, mesenchymal differentiation, and tumor-initiating ability. These actions are dependent on TAZ interacting with TEAD since all these effects were abrogated with TAZ could not bind to TEAD. We also show that TAZ and TEAD directly bind to mesenchymal gene promoters. Thus, TAZ-TEAD interaction is critically important in the mesenchymal shift and in the aggressive clinical behavior of GBM. We identified TAZ as a regulator of the mesenchymal transition in gliomas. TAZ could be used as a biomarker to both estimate prognosis and stratify patients into clinically relevant subgroups. Since mesenchymal transition is correlated to tumor aggressiveness, strategies to target and inhibit TAZ-TEAD and the downstream gene targets may be warranted in alternative treatment.
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Se analiza la influencia de las principales actuaciones selvicolas en la calidad de la madera. Turno, Espaciamiento, Poda, Abonado, Riego y Tratamiento contra plagas.
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Physical and social transformation processes that take place in urban contexts with strong spatial growth and hardly any economic development frequently have significant adverse impacts for the affected people, which tend to be made invisible. This paper presents an analytical framework to explore different ways to approach urban transformation processes (supply side), their impacts on the set of needs of the community (demand side) and their consequences on the urban environment as a whole (context). The proposed method has been used to assess three actions related to the physical and social transformation of the largest self-made settlement in the city of Dakar, Senegal, during the 2005–2012 period. Research findings show how exogenous interests are privileged over the common good when the affected citizens are not effectively involved in decision-making processes.
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The 436-amino acid protein enolase 1 from yeast was degraded in vitro by purified wild-type and mutant yeast 20S proteasome particles. Analysis of the cleavage products at different times revealed a processive degradation mechanism and a length distribution of fragments ranging from 3 to 25 amino acids with an average length of 7 to 8 amino acids. Surprisingly, the average fragment length was very similar between wild-type and mutant 20S proteasomes with reduced numbers of active sites. This implies that the fragment length is not influenced by the distance between the active sites, as previously postulated. A detailed analysis of the cleavages also allowed the identification of certain amino acid characteristics in positions flanking the cleavage site that guide the selection of the P1 residues by the three active β subunits. Because yeast and mammalian proteasomes are highly homologous, similar cleavage motifs might be used by mammalian proteasomes. Therefore, our data provide a basis for predicting proteasomal degradation products from which peptides are sampled by major histocompatibility complex class I molecules for presentation to cytotoxic T cells.
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Quantitative, chemically specific images of biological systems would be invaluable in unraveling the bioinorganic chemistry of biological tissues. Here we report the spatial distribution and chemical forms of selenium in Astragalus bisulcatus (two-grooved poison or milk vetch), a plant capable of accumulating up to 0.65% of its shoot dry biomass as Se in its natural habitat. By selectively tuning incident x-ray energies close to the Se K-absorption edge, we have collected quantitative, 100-μm-resolution images of the spatial distribution, concentration, and chemical form of Se in intact root and shoot tissues. To our knowledge, this is the first report of quantitative concentration-imaging of specific chemical forms. Plants exposed to 5 μM selenate for 28 days contained predominantly selenate in the mature leaf tissue at a concentration of 0.3–0.6 mM, whereas the young leaves and the roots contained organoselenium almost exclusively, indicating that the ability to biotransform selenate is either inducible or developmentally specific. While the concentration of organoselenium in the majority of the root tissue was much lower than that of the youngest leaves (0.2–0.3 compared with 3–4 mM), isolated areas on the extremities of the roots contained concentrations of organoselenium an order of magnitude greater than the rest of the root. These imaging results were corroborated by spatially resolved x-ray absorption near-edge spectra collected from selected 100 × 100 μm2 regions of the same tissues.
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The adenovirus type 2/5 E1A proteins transform primary baby rat kidney (BRK) cells in cooperation with the activated Ras (T24 ras) oncoprotein. The N-terminal half of E1A (exon 1) is essential for this transformation activity. While the C-terminal half of E1A (exon 2) is dispensable, a region located between residues 225 and 238 of the 243R E1A protein negatively modulates in vitro T24 ras cooperative transformation as well as the tumorigenic potential of E1A/T24 ras-transformed cells. The same C-terminal domain is also required for binding of a cellular 48-kDa phosphoprotein, C-terminal binding protein (CtBP). We have cloned the cDNA for CtBP via yeast two-hybrid interaction cloning. The cDNA encodes a 439-amino acid (48 kDa) protein that specifically interacts with exon 2 in yeast two-hybrid, in vitro protein binding, and in vivo coimmunoprecipitation analyses. This protein requires residues 225-238 of the 243R E1A protein for interaction. The predicted protein sequence of the isolated cDNA is identical to amino acid sequences obtained from peptides prepared from biochemically purified CtBP. Fine mapping of the CtBP-binding domain revealed that a 6-amino acid motif highly conserved among the E1A proteins of various human and animal adenoviruses is required for this interaction. These results suggest that interaction of CtBP with the E1A proteins may play a critical role in adenovirus replication and oncogenic transformation.
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Prolonged incubation of NIH 3T3 cells under the growth constraint of confluence results in the death of some cells in a manner suggestive of apoptosis. Successive rounds of prolonged incubation at confluence of the surviving cells produce increasing neoplastic transformation in the form of increments in saturation density and transformed focus formation. Cells from the postconfluent cultures are given a recovery period of various lengths to remove the direct inhibitory effect of confluence before their growth properties are studied. It is found that with each round of confluence the exponential growth rate of the cells at low densities gets lower and the size of isolated colonies of the same cells shows a similar progressive reduction. The decreased growth rate of cells from the third round of confluence persists for > 60 generations of growth at low density. The proportion of colonies containing giant cells is much higher after a 2-day recovery from confluence than after a 7-day recovery. Retardation of growth at low density and increased saturation density appear to be two sides of the same coin: both occur in the entire population of cells and precede the formation of transformed foci. We propose that the slowdown in growth and the formation of giant cells result from heritable damage to the cells, which in turn drives their transformation. Similar results have been reported for the survivors of x-irradiation and of treatment with chemical carcinogens and are associated with the aging process in animals. We suggest that these changes result from free radical damage to membrane lipids with particular damage to lysosomes. Proteases and nucleases would then be released to progressively modify the growth behavior and genetic stability of the cells toward autonomous proliferation.
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Research on the industrial transition in East Germany and its outcomes has long focused on the strategy of the Treuhand anstalt (IHA). According to institutionalists, David Stark and Lazlo Brust!: (1998), the powerful position of the German privatization agency was not only a result of German unification but also a function of a pathway rooted in the institutional peculiarities of the East German economy before 1989. This paper shows that neither a simple top-down perspective nor the pathway approach, as Stark and Brust!: suggested, are adequate for explaining the internal dynamic of enterprise transformation as well as the outcomes of this process. First of all, the dissolution of the former organizational structures and hierarchies was less coordinated by the 1HA than is often assumed. Often Kombinates fell apart more quickly from below than they could be dismantled from above since enterprises or their units chose the exit option and had good reasons to do so. Secondly, although the privatization by the 1HA resulted in the clear dominance of Western investors, the new ownership structure of East German industry as a whole could be characterized as a "capitalism without (East German) capitalists." In fact, what exists in East Germany is rather a kind of "small business capitalism" (KleinbetriebsknpitalifmllS) in which small-and medium-sized producers dominate the landscape. Finally, there was no single starting point in 1989. Two different industrial orders shaped the industrial history of the East German regions which were not destroyed between 1945-89, but rather transformed into the state socialist production system. It can be shown that these older historical patterns are relevant for transition and their outcomes as well.
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This paper demonstrates a mixed approach to the theme of the instrumentality of law by both analysing the goal of a legal transformation and the techniques adapted to achieve it. The correct recognition of a certain practical necessity has lead the Swiss Federal Tribunal to an intriguing judgement “Fussballclub Lohn-Fall” of 1997. The legal remedies provided for cases of unfair advantage have been then creatively modified praeter legem. The adaptation was strongly influenced by foreign legal patterns. The Swiss Code of Obligations of 1911 provides a norm in art. 21 on unfair advantage (unconscionable contract), prescribing that if one party takes unjustified advantage over the weaknesses of another in order to receive an excessive benefit, such a contract is avoidable. Its wording has been shaped over a hundred years ago and still remains intact. However, over the course of the 20th century the necessity for a more efficient protection has arisen. The legal doctrine and jurisprudence were constantly pointing out the incompleteness of the remedies provided by art. 21 of the Code of Obligations. In the “Fussballclub Lohn-Fall” (BGE 123 III 292) the Swiss Federal Tribunal finally introduced the possibility to modify the contract. Its decision has been described as “a sign of the zeitgeist, spirit of the time”. It was the Swiss legal doctrine that has imposed the new measure under the influence of the German “quantitative Teilnichtigkeit” (quantitative partial nullity). The historical heritage of the Roman laesio enormis has also played its role.
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Mode of access: Internet.
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This piece of art is a flipbook, analogous to the ones children play with as they make cartoon balls bounce with the quick flipping of pages between their thumb and index finger. However, instead of a playful scene, this flipbook is a commentary on Albanian Sworn Virgins. These are women from Northern Albania who, in their youth, swear to celibacy in order to gain the societal power that is exclusive to men in their culture. This flipbook demonstrates this cultural male-to-female shift and comments on its inability to ever be fully realized. This commentary is inspired by the words of Albanian Sworn Virgins in Elvira Dones’ documentary, Sworn Virgins, who feel betrayed by their biological need to menstruate and who view their reproductive system as a permanent obstacle in completing their societal shift. Just as a child’s flipbook tells a story, this flipbook illustrates the Albanian Sworn Virgins’ forever-unfinished transformation.
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The purpose of this article is to delimit the role of pragmatic specialization in the evolution of negation in French. The change in the marking of sentential negation is believed to proceed in characterized stages that would together constitute the Jespersen cycle. As a marker becomes the default expression of negation, the other markers do not necessarily fade away, and are maintained with specialized roles that include pragmatic functions. One such pragmatic function is that of activation (Dryer 1996), by which a proposition is presented as accessible to the hearer. Activation is shown to motivate the use of preverbal non that competes with 'ne' for several centuries. The claims that the emergence of postverbal pas in early French and the loss of 'ne' in contemporary spoken French are associated with activation are considered on the basis of novel data. It is concluded that pragmatic functions contribute to language change by providing marked options that may be conferred the default status in a grammatical paradigm.
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The fate of vitamin E and the formation and identification of its transformation products were investigated at different stages of the manufacturing process of commercially produced cross-linked (by γ-irradiation) UHMWPE stabilised with vitamin E (vitamin E infused-post irradiation) used for tibia-components (as articulating surfaces) in total knee arthroplasty (total knee replacement). Vitamin E (α-tocopherol) and its transformation products were extracted from microtomed Tibia films and the different products were separated, isolated, purified using high performance liquid chromatography (HPLC), and characterised by spectroscopic methods and LC-MS. The amount of vitamin E and that of the products formed in the different Tibia samples and in their extracts were also quantified using FTIR and HPLC analysis and calibration curves. Thorough analysis of the Tibia extracts has shown that a number of vitamin E transformation products were formed at different concentrations at two selected stages of the implant manufacturing process that is before and after sterilisation by γ-irradiation. The identified products were found to correspond mainly to different stereoisomeric forms of a small number of vitamin E transformation products. Most of the observed products were of dimeric and trimeric nature with their identity confirmed through a detailed study of their spectral and chromatographic characteristics. It was found that the products of vitamin E, prior to the sterilisation step but after the crosslinking and doping of vitamin E, were mainly the dihydroxydimers and trimers (Tibia samples at this stage are referred to as “Tibia-VEPE”). After sterilisation and completion of the manufacturing process, additional dimers of vitamin E were also formed (Tibia samples at this stage are referred to as ‘Tibia-VEPE-Sterile’), Furthermore, two tocopherol-derived aldehydes (aldehyde 5-formyl-γ-tocopherol and aldehyde 7-formyl-γ-tocopherol) were also formed but at very low concentrations especially in the Tibia-VEPE-Sterile samples. The question of whether vitamin E becomes chemically reacted (grafted) onto the polymer matrix during the manufacturing process of the Tibia is also addressed.
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A possibility of a strong change of an electromagnetic signal by a short sequence of time cycles of pulses that modulate the medium parameters is shown. The backward wave is demonstrated to be an inevitable result of the medium time change. Dependence of the relation between backward and forward waves on the parameters of the medium modulation is investigated. The finite statistical complexity of the electromagnetic signal transformed by a finite sequence of modulating cycles is calculated. Increase of the complexity with the number of cycles is shown.