869 resultados para Enabling and Disabling Factors


Relevância:

100.00% 100.00%

Publicador:

Resumo:

The basal transcription factor IIE (TFIIE) is thought to be one of the last factors to be assembled into a preinitiation complex (PIC) at eukaryotic promoters after RNA polymerase II and TFIIF have been incorporated. It was shown that a primary function of TFIIE is to recruit and cooperate with TFIIH in promoter melting. Here, we show that the large subunit of TFIIE (E56) can directly stimulate TBP binding to the promoter in the absence of other basal factors. The zinc-finger domain of E56, required for transcriptional activity, is critical for this function. In addition, the small subunit of TFIIE (E34) directly contacts DNA and TFIIA and thus providing a second mechanism for TFIIE to help binding of a TBP/IIA complex to the promoter, the first critical step in the PIC assembly. These studies suggest an alternative PIC assembly pathway in which TFIIE affects both TBP and TFIIH functions during initiation of RNA synthesis.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The objective of this study was to clarify the relative roles of medial versus luminal factors in the induction of thickening of the arterial intima after balloon angioplasty injury. Platelet-derived growth factor (PDGF) and thrombin, both associated with thrombosis, and basic fibroblast growth factor (bFGF), stored in the arterial wall, have been implicated in this process. To unequivocally isolate the media from luminally derived factors, we used a 20-μm thick hydrogel barrier that adhered firmly to the arterial wall to block thrombus deposition after balloon-induced injury of the carotid artery of the rat. Thrombosis, bFGF mobilization, medial repopulation, and intimal thickening were measured. Blockade of postinjury arterial contact with blood prevented thrombosis and dramatically inhibited both intimal thickening and endogenous bFGF mobilization. By blocking blood contact on the two time scales of thrombosis and of intimal thickening, and by using local protein release to probe, by reconstitution, the individual roles of PDGF-BB and thrombin, we were able to conclude that a luminally derived factor other than PDGF or thrombin is required for the initiation of cellular events leading to intimal thickening after balloon injury in the rat. We further conclude that a luminally derived factor is required for mobilization of medial bFGF.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Objectives: To explore the circumstances and factors that explain variations in response to a cardiac event and to identify potentially modifiable factors.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Objective: To compare the implications of four widely used cholesterol screening and treatment guidelines by applying them to a population in the United Kingdom.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

With the completion of the determination of its entire genome sequence, one of the next major targets of Bacillus subtilis genomics is to clarify the whole gene regulatory network. To this end, the results of systematic experiments should be compared with the rich source of individual experimental results accumulated so far. Thus, we constructed a database of the upstream regulatory information of B.subtilis (DBTBS). The current version was constructed by surveying 291 references and contains information on 90 binding factors and 403 promoters. For each promoter, all of its known cis-elements are listed according to their positions, while these cis-elements are aligned to illustrate their consensus sequence for each transcription factor. All probable transcription factors coded in the genome were classified with the Pfam motifs. Using this database, we compared the character of B.subtilis promoters with that of Escherichia coli promoters. Our database is accessible at http://elmo.ims.u-tokyo.ac.jp/dbtbs/.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

In postnatal tissues, angiogenesis occurs in nontumoral conditions on appropriate stimuli. In the nervous tissue, hypoxia, neural graft, increased neural function, and synaptic activity are associated with neoangiogenesis. We have investigated the occurrence of neoangiogenesis in the superior cervical ganglia (scg) of newborn rats treated for 8–21 days with 6-hydroxy-dopamine (6-OHDA), nerve growth factor (NGF), or 6-OHDA + NGF. The two latter treatments induced a significant increase in scg size. However, the increase after combined treatment far exceeded that of NGF alone. Similarly, histological and histochemical analysis revealed neuronal hypertrophy and endothelial cell hyperplasia associated with stromal hypertrophy (as described by laminin immunostaining) and increased vascular bed (as revealed by platelet/endothelial cell adhesion molecule-1 immunostaining) in 6-OHDA + NGF-treated pups. NGF, either alone or associated with 6-OHDA, also induced a significant up-regulation of NADPH diaphorase, neuronal nitric oxide synthase, and vascular endothelial growth factor expression in scg neurons. The present investigation suggests that the increase of scg size induced by NGF and 6-OHDA + NGF is associated with neoangiogenesis, and that the induction of vasoactive and angiogenic factors in neurons represents a further and previously undisclosed effect of NGF.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The incubation period (IP) and the neuropathology of transmissible spongiform encephalopathies (TSEs) have been extensively used to distinguish prion isolates (or strains) inoculated into panels of inbred mouse strains. Such studies have shown that the bovine spongiform encephalopathy (BSE) agent is indistinguishable from the agent causing variant Creutzfeldt–Jakob disease (vCJD), but differs from isolates of sporadic CJD, reinforcing the idea that the vCJD epidemic in Britain results from consumption of contaminated beef products. We present a mouse model for genetic and environmental factors that modify the incubation period of BSE cross-species transmission. We have used two mouse strains that carry the same prion protein (PrP) allele, but display a 100-day difference in their mean IP following intracerebral inoculation with primary BSE isolate. We report genetic effects on IP that map to four chromosomal regions, and in addition we find significant factors of host environment, namely the age of the host's mother, the age of the host at infection, and an X-cytoplasm interaction in the host.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

En este trabajo se exploraron relaciones existentes entre las características de personalidad, género y la presencia de depresión, siguiendo la linea de investigación de Carrillo, Rojo y Staats (2004). Se intentó encontrar perfiles de personalidad caracterizados por determinados rasgos que fueran significativamente distintos entre hombres y mujeres y que a su vez se asociaran a una mayor presencia de síntomas depresivos. Esto se llevó a cabo en dos muestras de distintos países y culturas por separado: Chile (N= 448, 257 varones (57.37%) y 190 mujeres (42.41%), y un rango etario de 17-65) y España (N = 578, 196 varones (33.9%) y 381 mujeres (65,9%), y un rango etario de 17-67 ), con el propósito de aportar evidencia respecto de cómo afecta la cultura, como factor ambiental, en la conformación de la personalidad a partir de repertorios de aprendizajes. Orientado a eso en el presente trabajo se intentó buscar asociaciones significativas entre las dimensiones de Personalidad propuestas por Eysenk (1975), en el EPQ y EPQ-R, por los factores de Personalidad de los Cinco grandes a partir del NEO PI y del NEO PI-R (Costa y McCrae, 1985, citado en Carrillo et al. 2004) y otras variables clínicas, como rasgos de personalidad esquizotipicos, frecuencia e intensidad de emociones, habilidades sociales y sintomatología clínica. Las características de personalidad se compararon en función del género y finalmente se analizó si las diferencias de personalidad pudieron predecir depresión a partir del Beck Depression Inventory, (Beck, Rush, Shaw y Emery, 1979)...

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Understanding spatial distributions and how environmental conditions influence catch-per-unit-effort (CPUE) is important for increased fishing efficiency and sustainable fisheries management. This study investigated the relationship between CPUE, spatial factors, temperature, and depth using generalized additive models. Combinations of factors, and not one single factor, were frequently included in the best model. Parameters which best described CPUE varied by geographic region. The amount of variance, or deviance, explained by the best models ranged from a low of 29% (halibut, Charlotte region) to a high of 94% (sablefish, Charlotte region). Depth, latitude, and longitude influenced most species in several regions. On the broad geographic scale, depth was associated with CPUE for every species, except dogfish. Latitude and longitude influenced most species, except halibut (Areas 4 A/D), sablefish, and cod. Temperature was important for describing distributions of halibut in Alaska, arrowtooth flounder in British Columbia, dogfish, Alaska skate, and Aleutian skate. The species-habitat relationships revealed in this study can be used to create improved fishing and management strategies.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Background: Intimate partner violence (IPV) against women occurs in all countries, all cultures and at every level of society; however, some populations may be at greater risk than others. The aim of this study was to explore IPV prevalence among Ecuadorian, Moroccan and Romanian immigrant women living in Spain and its possible association with their personal, family, social support and immigration status characteristics. Methods: Cross-sectional study of 1607 adult immigrant women residing in Barcelona, Madrid and Valencia (2011). Prevalence rates and adjusted odds ratios (AORs) were calculated, with current IPV being the outcome. Different women’s personal (demographic), family, social support and immigration status characteristics were considered as explicative and control variables. All analyses were separated by women’s country of origin. Results: Current IPV prevalence was 15.57% in Ecuadorians, 10.91% in Moroccans and 8.58% in Romanians. Some common IPV factors were found, such as being separated and/or divorced. In Romanians, IPV was also associated with lack of social support [AOR 5.96 (1.39–25.62)] and low religious involvement [AOR 2.17 (1.06–4.43)]. The likelihood of current IPV was lower among women without children or other dependants in this subgroup [AOR 0.29 (0.093–0.92)]. Conclusion: The IPV prevalence rates obtained for Moroccan, Romanian and Ecuadorian women residing in Spain were similar. Whereas the likelihood of IPV appeared to be relatively evenly distributed among Moroccan and Ecuadorian women, it was higher among Romanian women in socially vulnerable situations related to family responsibilities and the lack of support networks. The importance of intervention in the process of separation and divorce was common to all women.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

In order to evaluate taxonomic and environmental control on the preservation pattern of brachiopod accumulations, sedimentologic and taphonomic data have been integrated with those inferred from the structure of brachiopod accumulations from the easternmost Lower Jurassic Subbetic deposits in Spain. Two brachiopod communities (Praesphaeroidothyris and Securina communities) were distinguished showing a mainly free-lying way of life in soft-bottom habitats. Three taphofacies are discriminated based on proportion of disarticulation, fragmentation, packing, and shell filling. Taphofacies 1 is represented by thinly fragmented, dispersed brachiopod shells in wackestone beds. Taphofacies 2 is spatially restricted to small lenses where shells are poorly fragmented, rarely disarticulated, usually void filled, and highly packed. Taphofacies 3 is represented by mud or cement filled, loosely packed, articulated brachiopods forming large pocket-like structures. Temporal and spatial averaging were minimally involved in taphofacies 2 and 3. It is interpreted that patchy preservation implies preservation of primary original patchiness of brachiopod communities on the seafloor. The origin of shell-rich taphofacies (2 and 3) is related to rapid burial due to episodic storm activity, while shell-poor taphofacies 1 records background conditions. The nature and comparative diversity of these taphofacies underscores the importance of rapid burial for shell beds preservation. Differences in preservation between taphofacies 2 and 3 are mainly related to environmental criteria, most importantly storm energy and water depth. In contrast, the taxonomic-specific pattern of the communities is a subordinate element of control, controlling only minor within-taphofacies differences in preservation.