Interactions Between Silver Nanoparticles and Culture Medium Biomolecules with Dose and Time Dependencies.

The interaction between silver nanoparticles (AgNPs) and molecules producing coronas plays a key role in cytotoxicity mechanisms. Once adsorbed coronas determine the destiny of nanomaterials in vivo, their effective deployment in the biomedical field requires a comprehensive understanding of the dynamic interactions of biomolecules with nanoparticles. In this work, we characterized 40 nm AgNPs in three different nutritional cell media at different molar concentrations and incubation times to study the binding mechanism of molecules on surface nanoparticles.

Glucose restriction in Saccharomyces cerevisiae modulates the phosphorylation pattern of the 20S proteasome and increases its activity.

Caloric restriction is known to extend the lifespan and/or improve diverse physiological parameters in a vast array of organisms. In the yeast Saccharomyces cerevisiae, caloric restriction is performed by reducing the glucose concentration in the culture medium, a condition previously associated with increased chronological lifespan and 20S proteasome activity in cell extracts, which was not due to increased proteasome amounts in restricted cells. Herein, we sought to investigate the mechanisms through which glucose restriction improved proteasome activity and whether these activity changes were associated with modifications in the particle conformation.

Exfoliative Toxin E, Oligomeric State and Flip of P186: Implications for Its Action Mechanism.

Staphylococcal exfoliative toxins (ETs) are glutamyl endopeptidases that specifically cleave the Glu381-Gly382 bond in the ectodomains of desmoglein 1 (Dsg1) via complex action mechanisms. To date, four ETs have been identified in different strains and ETE is the most recently characterized. The unusual properties of ETs have been attributed to a unique structural feature, i.

Influence of the Mixtures of Vegetable Oil and Vitamin E over the Microstructure and Rheology of Organogels.

Candelilla wax (CW) and 12-hydroxystearic acid (12HSA) are classic solid-fiber-matrix organogelators. Despite the high number of studies using those ingredients in oily systems, there is scarce literature using a mixture of oil and antioxidants. Vitamin E (VE) is an important candidate for its lipophilicity and several applications on pharmaceutical, cosmetics, and food industries.

Nanoscopic Structure of Complexes Formed between DNA and the Cell-Penetrating Peptide Penetratin.

One of the most remarkable examples of cell-penetrating peptides (CPPs) is , a 16-mer fragment derived from the homeobox. Understanding the structure of /DNA complexes is a key factor for the successful design of new vectors for gene delivery and may assist in optimizing molecular carriers based on CPPs. Herein, we present a comprehensive study on the nanoscale structure of noncovalent complexes formed between and DNA.

Mind the Microgap in Iridescent Cellulose Nanocrystal Films.

A new photonic structure is produced from cellulose nanocrystal iridescent films reflecting both right and left circularly polarized light. Micrometer-scale planar gaps perpendicular to the films' cross-section between two different left-handed films' cholesteric domains are impregnated with a nematic liquid crystal. This photonic feature is reversibly tuned by the application of an electric field or a temperature variation.

A Simple and Fast Semiautomatic Procedure for the Atomistic Modeling of Complex DNA Polyhedra.

A semiautomatic procedure to build complex atomistic covalently linked DNA nanocages has been implemented in a user-friendly, free, and fast program. As a test set, seven different truncated DNA polyhedra, composed by B-DNA double helices connected through short single-stranded linkers, have been generated. The atomistic structures, including a tetrahedron, a cube, an octahedron, a dodecahedron, a triangular prism, a pentagonal prism, and a hexagonal prism, have been probed through classical molecular dynamics and analyzed to evaluate their structural and dynamical properties and to highlight possible building faults.

Microfluidic Assembly of pDNA/Cationic Liposome Lipoplexes with High pDNA Loading for Gene Delivery.

Microfluidics offers unique characteristics to control the mixing of liquids under laminar flow. Its use for the assembly of lipoplexes represents an attractive alternative for the translation of gene delivery studies into clinical trials on a sufficient throughput scale. Here, it was shown that the microfluidic assembly of pDNA/cationic liposome (CL) lipoplexes allows the formation of nanocarriers with enhanced transfection efficiencies compared with the conventional bulk-mixing (BM) process under high pDNA loading conditions.

Influence of the single-strand linker composition on the structural/dynamical properties of a truncated octahedral DNA nano-cage family.

The structural/dynamical properties of three truncated octahedral DNA nano-cages composed by identical double helices but single strand linkers with different composition, namely 7 thymidines, 7 adenines, and 7 alternated thymidines and adenines, have been investigated through classical molecular dynamics simulations. Trajectories have been analyzed to investigate the role of the linkers in defining nano-cages stability and flexibility, including possible influence on the internal cages motions. The data indicate that the cages behavior is almost identical and that the structural/dynamical parameters measured along the trajectories are not particularly affected by the presence of different bases.

Redox regulation of the proteasome via S-glutathionylation.

The proteasome is a multimeric and multicatalytic intracellular protease responsible for the degradation of proteins involved in cell cycle control, various signaling processes, antigen presentation, and control of protein synthesis. The central catalytic complex of the proteasome is called the 20S core particle. The majority of these are flanked on one or both sides by regulatory units.

Structure of the haptoglobin-haemoglobin complex.

Red cell haemoglobin is the fundamental oxygen-transporting molecule in blood, but also a potentially tissue-damaging compound owing to its highly reactive haem groups. During intravascular haemolysis, such as in malaria and haemoglobinopathies, haemoglobin is released into the plasma, where it is captured by the protective acute-phase protein haptoglobin. This leads to formation of the haptoglobin-haemoglobin complex, which represents a virtually irreversible non-covalent protein-protein interaction.

Small angle x-ray scattering of the hemoglobin from Biomphalaria glabrata.

The hemoglobin from Biomphalaria glabrata is an extracellular respiratory protein of high molecular mass composed by subunits of 360 kDa, each one containing two 180 kDa chains linked by disulfide bridges. In this work, small angle x-ray scattering (SAXS) measurements were performed with the hemoglobin at pH 5.0 and 7.

Solution studies and structural model of the extracellular domain of the human amyloid precursor protein.

The amyloid precursor protein (APP) is the precursor of the beta-amyloid peptide (Abeta), which is centrally related to the genesis of Alzheimer's disease (AD). In addition, APP has been suggested to mediate and/or participate in events that lead to neuronal degeneration in AD. Despite the fact that various aspects of the cell biology of APP have been investigated, little information on the structure of this protein is available.