Sensitivity of transcription factors to DNA methylation.

Dynamic binding of transcription factors (TFs) to regulatory elements controls transcriptional states throughout organism development. Epigenetics modifications, such as DNA methylation mostly within cytosine-guanine dinucleotides (CpGs), have the potential to modulate TF binding to DNA. Although DNA methylation has long been thought to repress TF binding, a more recent model proposes that TF binding can also inhibit DNA methylation. Here, we review the possible scenarios by which DNA methylation and TF binding affect each other. Further in vivo experiments will be required to generalize these models.journal article2019 Nov 222019 11 22importe

Análise e descrição das tipologias de comunicação para transferência nos dias de campo do programa Terra Sul dos anos de 2008 e 2009.

O objeto deste trabalho é fazer uma análise das tipologias de comunicação para transferência que estão presentes nos dias de campo dos programas Terra Sul, produzidos pela Embrapa Clima Temperado, dividindo-as, basicamente, entre as categorias convencional, informal e construtivista. Observando os dias de campo, analisar quais são as novas maneiras de se fazer comunicação para a transferência

Modulating membrane shape and mechanics of minimal cells by light: area increase, softening and interleaflet coupling of membrane models doped with azobenzene-lipid photoswitches

Light can effectively interrogate biological systems providing control over complex cellular processes. Particularly advantageous features of photo-induced processes are reversibility, physiological compatibility, and spatiotemporal precision. Understanding the underlying biophysics of light-triggered changes in bio-systems is crucial for cell viability and optimizing clinical applications of photo-induced processes in biotechnology, optogenetics and photopharmacology. Employing membranes doped with the photolipid azobenzene-phosphatidylcholine (azo-PC), we provide a holistic picture of light-triggered changes in membrane morphology, mechanics and dynamics. We combine microscopy of giant vesicles as minimal cell models, Langmuir monolayers, and molecular dynamics simulations. We employ giant vesicle elelctrodeformation as a facile and accurate approach to quantify the magnitude, reversibility and kinetics of light-induced area expansion/shrinkage as a result of azo-PC photoisomerization and content. Area increase as high as ~25% and a 10-fold decrease in the membrane bending rigidity is observed upon trans-to-cis azo-PC isomerization. These results are in excellent agreement with simulations data and monolayers. Simulations also show that trans-to-cis isomerization of azo-PC decreases the membrane leaflet coupling. We demonstrate that light can be used to finely manipulate the shape and mechanics of photolipid-doped minimal cell models and liposomal drug carriers, thus, presenting a promising therapeutic alternative for the repair of cellular disorders.Competing Interest StatementThe authors have declared no competing interest

Determinação dos compostos antioxidantes e avaliação química em amostras de erva-mate.

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Local Optical Spectroscopy in Quantum Confined Systems: A Theoretical Description

A theoretical description of local absorption is proposed in order to investigate spectral variations on a length scale comparable with the extension of the relevant quantum states. A general formulation is derived within the density-matrix formalism including Coulomb correlation, and applied to the prototypical case of coupled quantum wires. The results show that excitonic effects may have a crucial impact on the local absorption with implications for the spatial resolution and the interpretation of near-field optical spectra.Comment: To appear in Phys. Rev. Lett. - 11 pages, 3 PostScript figures (1 figure in colors) embedded. Uses RevTex, and psfig style

Caracterização da composição química, minerais e perfil de ácidos graxos em amostras de pinhão - safra 2014.

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Ordering of ferromagnetic nanoparticles in nematic liquid crystals

Dispersions of magnetic nanoparticles in a nematic liquid crystal were investigated as magnetic fields were applied in three different boundary condition geometries: (i) planar substrates and B ⊥ n, (ii) planar substrates and B / n, and (iii) homeotropic substrates and B ⊥ n. Particle chaining is observed when a magnetic field is applied, with a periodicity perpendicular to the chains. Furthermore, linear chains are observed for the magnetic field applied perpendicular to the director, while zigzag chains are formed when the magnetic field direction is parallel to the director field. This is attributed to a change from a dipolar defect configuration around dispersed nanoparticles, to a quadrupolar one, i.e. the change from satellite to Saturn-ring defects. This effect is largely independent of the sample thickness. The dynamic development of the chain length, as well as their two-dimensional order parameter was studied in all cases. Chain lengths increased rapidly until saturation at approximately l = 30 μm after a time of about t = 10 s. Similarly, the chain order parameters increased until saturation between S = 0.8-0.9, independent of sample geometry

Determinação dos compostos fenólicos totais em diferentes extratos de erva-mate.

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