997 resultados para degenerate primers


Relevância:

10.00% 10.00%

Publicador:

Resumo:

Les restes humanes deIs períodes epipaleolític i mesolític estan pobrament representades a la Península Iberica, tot i que existeixen dos jaciments mesolítics excepcional s a Muge, Portugal (Moita do Sebastiao i Cabe~o da Arruda), amb uns 67 individus, i un altre de recentment excavat a Oliva (El Collado, Valencia), on s'han trobat uns 15 individus. EIs primers estan datats entre 7.240 i 6.300 a.P. (Ferreira 1994: 664-674), mentre que el darrer té una datació de 7.640-7.570 a.P (Aparicio 1989). Ambdós jaciments es troben en zones properes a estuaris de rius o a la costa, la qual cosa permetia 1'explotació intensiva de recursos marins molt variats. Aquest tipus d' economia condicionava un tipus de vida força sedentaria i a més a més, va permetre un increment en la densitat de població, que hauria tingut lloc probablement entre el 8.000-7.000 a.e. (Ferreira 1994: 664-674). A Catalunya, s'han excavat fins ara pocs jaciments importants d'aquests periodes (Martín y Vaquer 1995: 35-73), tots d'ells en zones d'interior i corresponents presumiblement a grups petits de caçadors-recol·lectors, força diferents dels posteriors assentaments humans més grans com Muge i Oliva. De tots aquests jaciments, només a la Balma de Guilanya (Naves, Solsones) s'han trobat restes humanes que es puguin atribuir sense cap mena de dubte als nivells epipaleolítics.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Source/Description: The probe used is a 98 bp fragment amplified by PCR from a cDNA clone of the CFTR gene or from genomic DNA corresponding to exon 10, using two primers from this exon (1)...

Relevância:

10.00% 10.00%

Publicador:

Resumo:

El diposit consisteix en dos filons E-W, tallats per un altre N-S. El rebliment filonia ès zonat amb esfalerita- galena-calcita als nivells profunds i galena-baritina als superiors. Els elements traça en esfalerites i galenes, plenament separades, han estat analitzats mitjancant fluorescència de raigs X. Els resultats mostren que l'esfalerita concentra la majoria d'elements traça, preferentment Fe, Co, Cd, Sn, Sb, Ga, Cu, Ge i Ag, amb una bona correlació entre els sis primers. La galena concentra únicament Sb, Ag i As, amb bona correlació entre els dos primers. Els continguts en elements traça estan homogèniament distribuits en tot el diposit.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

[cat] Besley i Rosen -1998- van ser els primers autors en estimar empíricament la rellevància de les externalitats impositives verticals. Aquests autors varen fer-ho per al cas dels impostos sobre la benzina i el tabac, en concret, per al cas dels EEUU. Ara bé, no varen tenir en compte les diferències en el nivell de vida entre Estats: àrees amb un nivell elevat paguen menys en termes reals que àrees amb un nivell de vida baix, doncs l'impost unitari sobre la benzina o sobre el tabac no difereix d'acord amb l'Estat on l'impost s'aplica. En conseqüència, proposem que la competència impositiva vertical sigui estimada deflactant totes les variables monetàries utilitzant l'anomenat "House Price Index (HPI)", el qual està disponible al nivell dels Estats. Això genera una variable impositiva federal expressada en termes reals i que presenta variació entre Estats. Aquesta estratègia empírica ens permet diferenciar entre la interdependència vertical entre els tipus impositius federals i els estatals de shocks agregats al llarg del temps, utilitzant dades per als EEUU durant el període 1975 a 2006 per a benzina i tabac. Trobem una nivell significatiu de competència impositiva horitzontal, la qual és més elevada en el cas del tabac, però en cap cas reacció impositiva vertical. Els resultats són robustos al període analitzat.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Shedding of intercellular adhesion molecule 1 (ICAM-1) is believed to play a role in tumor cell resistance to cell-mediated cytotoxicity. However, the mechanism whereby ICAM-1 is shed from the surface of tumor cells remains unclear. In this study, we have addressed the possibility that matrix metalloproteinases are implicated in ICAM-1 shedding. Our observations suggest a functional relationship between ICAM-1 and matrix metalloproteinase 9 (MMP-9) whereby ICAM-1 provides a cell surface docking mechanism for proMMP-9, which, upon activation, proteolytically cleaves the extracellular domain of ICAM-1 leading to its release from the cell surface. MMP-9-dependent shedding of ICAM-1 is found to augment tumor cell resistance to natural killer (NK) cell-mediated cytotoxicity. Taken together, our observations propose a mechanism for ICAM-1 shedding from the cell surface and provide support for MMP involvement in tumor cell evasion of immune surveillance.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

[cat] Besley i Rosen -1998- van ser els primers autors en estimar empíricament la rellevància de les externalitats impositives verticals. Aquests autors varen fer-ho per al cas dels impostos sobre la benzina i el tabac, en concret, per al cas dels EEUU. Ara bé, no varen tenir en compte les diferències en el nivell de vida entre Estats: àrees amb un nivell elevat paguen menys en termes reals que àrees amb un nivell de vida baix, doncs l'impost unitari sobre la benzina o sobre el tabac no difereix d'acord amb l'Estat on l'impost s'aplica. En conseqüència, proposem que la competència impositiva vertical sigui estimada deflactant totes les variables monetàries utilitzant l'anomenat "House Price Index (HPI)", el qual està disponible al nivell dels Estats. Això genera una variable impositiva federal expressada en termes reals i que presenta variació entre Estats. Aquesta estratègia empírica ens permet diferenciar entre la interdependència vertical entre els tipus impositius federals i els estatals de shocks agregats al llarg del temps, utilitzant dades per als EEUU durant el període 1975 a 2006 per a benzina i tabac. Trobem una nivell significatiu de competència impositiva horitzontal, la qual és més elevada en el cas del tabac, però en cap cas reacció impositiva vertical. Els resultats són robustos al període analitzat.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Diesel oil is a compound derived from petroleum, consisting primarily of hydrocarbons. Poor conditions in transportation and storage of this product can contribute significantly to accidental spills causing serious ecological problems in soil and water and affecting the diversity of the microbial environment. The cloning and sequencing of the 16S rRNA gene is one of the molecular techniques that allows estimation and comparison of the microbial diversity in different environmental samples. The aim of this work was to estimate the diversity of microorganisms from the Bacteria domain in a consortium specialized in diesel oil degradation through partial sequencing of the 16S rRNA gene. After the extraction of DNA metagenomics, the material was amplified by PCR reaction using specific oligonucleotide primers for the 16S rRNA gene. The PCR products were cloned into a pGEM-T-Easy vector (Promega), and Escherichia coli was used as the host cell for recombinant DNAs. The partial clone sequencing was obtained using universal oligonucleotide primers from the vector. The genetic library obtained generated 431 clones. All the sequenced clones presented similarity to phylum Proteobacteria, with Gammaproteobacteria the most present group (49.8 % of the clones), followed by Alphaproteobacteira (44.8 %) and Betaproteobacteria (5.4 %). The Pseudomonas genus was the most abundant in the metagenomic library, followed by the Parvibaculum and the Sphingobium genus, respectively. After partial sequencing of the 16S rRNA, the diversity of the bacterial consortium was estimated using DOTUR software. When comparing these sequences to the database from the National Center for Biotechnology Information (NCBI), a strong correlation was found between the data generated by the software used and the data deposited in NCBI.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

We study the problem of front propagation in the presence of inertia. We extend the analytical approach for the overdamped problem to this case, and present numerical results to support our theoretical predictions. Specifically, we conclude that the velocity and shape selection problem can still be described in terms of the metastable, nonlinear, and linear overdamped regimes. We study the characteristic relaxation dynamics of these three regimes, and the existence of degenerate (¿quenched¿) solutions.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Using Monte Carlo simulations we study the dynamics of three-dimensional Ising models with nearest-, next-nearest-, and four-spin (plaquette) interactions. During coarsening, such models develop growing energy barriers, which leads to very slow dynamics at low temperature. As already reported, the model with only the plaquette interaction exhibits some of the features characteristic of ordinary glasses: strong metastability of the supercooled liquid, a weak increase of the characteristic length under cooling, stretched-exponential relaxation, and aging. The addition of two-spin interactions, in general, destroys such behavior: the liquid phase loses metastability and the slow-dynamics regime terminates well below the melting transition, which is presumably related with a certain corner-rounding transition. However, for a particular choice of interaction constants, when the ground state is strongly degenerate, our simulations suggest that the slow-dynamics regime extends up to the melting transition. The analysis of these models leads us to the conjecture that in the four-spin Ising model domain walls lose their tension at the glassy transition and that they are basically tensionless in the glassy phase.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

We investigate within mean-field theory the influence of a one-dimensional optical lattice and of trapped degenerate fermions on the critical rotational frequency for vortex line creation in a Bose-Einstein condensate. We consider laser intensities of the lattice such that quantum coherence across the condensate is ensured. We find a sizable decrease of the thermodynamic critical frequency for vortex nucleation with increasing applied laser strength and suggest suitable parameters for experimental observation. Since 87Rb-40K mixtures may undergo collapse, we analyze the related question of how the optical lattice affects the mechanical stability of the system.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Plasmodium sporozoites make a remarkable journey from the mosquito midgut to the mammalian liver. The sporozoite's major surface protein, circumsporozoite protein (CSP), is a multifunctional protein required for sporozoite development and likely mediates several steps of this journey. In this study, we show that CSP has two conformational states, an adhesive conformation in which the C-terminal cell-adhesive domain is exposed and a nonadhesive conformation in which the N terminus masks this domain. We demonstrate that the cell-adhesive domain functions in sporozoite development and hepatocyte invasion. Between these two events, the sporozoite must travel from the mosquito midgut to the mammalian liver, and N-terminal masking of the cell-adhesive domain maintains the sporozoite in a migratory state. In the mammalian host, proteolytic cleavage of CSP regulates the switch to an adhesive conformation, and the highly conserved region I plays a critical role in this process. If the CSP domain architecture is altered such that the cell-adhesive domain is constitutively exposed, the majority of sporozoites do not reach their target organs, and in the mammalian host, they initiate a blood stage infection directly from the inoculation site. These data provide structure-function information relevant to malaria vaccine development.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Glycerol, a product of adipose tissue lipolysis, is an important substrate for hepatic glucose synthesis. However, little is known about the regulation of hepatic glycerol metabolism. Here we show that several genes involved in the hepatic metabolism of glycerol, i.e., cytosolic and mitochondrial glycerol 3-phosphate dehydrogenase (GPDH), glycerol kinase, and glycerol transporters aquaporin 3 and 9, are upregulated by fasting in wild-type mice but not in mice lacking PPARalpha. Furthermore, expression of these genes was induced by the PPARalpha agonist Wy14643 in wild-type but not PPARalpha-null mice. In adipocytes, which express high levels of PPARgamma, expression of cytosolic GPDH was enhanced by PPARgamma and beta/delta agonists, while expression was decreased in PPARgamma(+/-) and PPARbeta/delta(-/-) mice. Transactivation, gel shift, and chromatin immunoprecipitation experiments demonstrated that cytosolic GPDH is a direct PPAR target gene. In line with a stimulating role of PPARalpha in hepatic glycerol utilization, administration of synthetic PPARalpha agonists in mice and humans decreased plasma glycerol. Finally, hepatic glucose production was decreased in PPARalpha-null mice simultaneously fasted and exposed to Wy14643, suggesting that the stimulatory effect of PPARalpha on gluconeogenic gene expression was translated at the functional level. Overall, these data indicate that PPARalpha directly governs glycerol metabolism in liver, whereas PPARgamma regulates glycerol metabolism in adipose tissue.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The Complete Arabidopsis Transcriptome Micro Array (CATMA) database contains gene sequence tag (GST) and gene model sequences for over 70% of the predicted genes in the Arabidopsis thaliana genome as well as primer sequences for GST amplification and a wide range of supplementary information. All CATMA GST sequences are specific to the gene for which they were designed, and all gene models were predicted from a complete reannotation of the genome using uniform parameters. The database is searchable by sequence name, sequence homology or direct SQL query, and is available through the CATMA website at http://www.catma.org/.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The transcription factor serum response factor (SRF) plays a crucial role in the development of several organs. However, its role in the skin has not been explored. Here, we show that keratinocytes in normal human and mouse skin expressed high levels of SRF but that SRF expression was strongly downregulated in the hyperproliferative epidermis of wounded and psoriatic skin. Keratinocyte-specific deletion within the mouse SRF locus during embryonic development caused edema and skin blistering, and all animals died in utero. Postnatal loss of mouse SRF in keratinocytes resulted in the development of psoriasis-like skin lesions. These lesions were characterized by inflammation, hyperproliferation, and abnormal differentiation of keratinocytes as well as by disruption of the actin cytoskeleton. Ultrastructural analysis revealed markedly reduced cell-cell and cell-matrix contacts and loss of cell compaction in all epidermal layers. siRNA-mediated knockdown of SRF in primary human keratinocytes revealed that the cytoskeletal abnormalities and adhesion defects were a direct consequence of the loss of SRF. In contrast, the hyperproliferation observed in vivo was an indirect effect that was most likely a consequence of the inflammation. These results reveal that loss of SRF disrupts epidermal homeostasis and strongly suggest its involvement in the pathogenesis of hyperproliferative skin diseases, including psoriasis.