Gallic Acid‐Loaded Zein Nanoparticles by Electrospraying Process

Currently, electrospraying is a novel process for obtaining the nanoparticles from biopolymers. Zein nanoparticles have been obtained by this method and used to protect both hydrophilic and hydrophobic antioxidant molecules from environmental factors. The objective of this work was to prepare and characterize gallic acid‐loaded zein nanoparticles obtained by the electrospraying process to provide protection to gallic acid from environmental factors. Thus, it was related to the concentration of gallic acid in physicochemical and rheological properties of the electrosprayed solution, and also to equipment parameters, such as voltage, flow rate, and distance of the collector in morphology, and particle size. The physicochemical properties showed a relationship in the formation of a Taylor cone, in which at a low concentration of gallic acid (1% w/v), low viscosity (0.00464 ± 0.00001 Pa·s), and density (0.886 ± 0.00002 g/cm³), as well as high electrical conductivity (369 ± 4.3 µs/cm), forms a stable cone‐jet mode. The rheological properties and the Power Law model of the gallic acid‐zein electrosprayed solution demonstrated Newtonian behavior (n = 1). The morphology and size of the particle were dependent on the concentration of gallic acid. Electrosprayed parameters with high voltage (15 kV), low flow rate (0.1 mL/hr), and short distance (10 cm) exhibited a smaller diameter and spherical morphology. FT–IR showed interaction in the gallic acid‐loaded zein nanoparticle by hydrogen bonds. Therefore, the electrospraying process is a feasible technique for obtaining gallic acid‐loaded zein nanoparticles and providing potential protection to gallic acid from environmental factors.     

Acetylation of hydroxytyrosol enhances its transport across differentiated Caco-2 cell monolayers

Hydroxytyrosol and hydroxytyrosyl acetate are two well-known phenolic compounds with antioxidant properties that are present in virgin olive oil. Since the in vivo biological activity of polyphenols is dependent on their intestinal absorption and metabolism, the absorption of hydroxytyrosol and hydroxytyrosyl acetate and the extent to which they are conjugated and metabolised during transfer across intestinal Caco-2/TC7 cell monolayers, was investigated. LC-DAD and LC-MS were used for the quantification and identification of metabolites. Further evidence was obtained by observing metabolite susceptibility to β-glucuronidase treatment and by comparison of products of in vitro conjugation reactions of authentic phenolics with those produced by the CaCo-2 cells. Homovanillyl alcohol was the only conjugate detected as a result of hydroxytyrosol metabolism, and accounted for 20% of the total metabolites detected in the basolateral compartment after 2 h of incubation. Hydroxytyrosyl acetate was largely converted into free hydroxytyrosol (38.4%) and subsequently metabolised into homovanillyl alcohol (6.7%). In addition, hydroxytyrosyl acetate glucuronide (17.4%) together with non-metabolised hydroxytyrosyl acetate (37.5%) were also detected. Both hydroxytyrosyl acetate and hydroxytyrosol were transferred across human Caco-2/TC7 cell monolayers, but the acetylated compound exhibited an apparent permeability (Papp_AP→BL/Papp _BL→AP) 2.1-fold higher than free hydroxytyrosol. For both compounds, all conjugates were preferentially transported to the basolateral side. These results show that the acetylation of hydroxytyrosol significantly increases its transport across the small intestinal epithelial cell barrier, and supports further research into hydroxytyrosyl acetate as a hydroxytyrosol prodrug offering enhanced bioavailability.     

Synthesis,characterization and rheological properties of multiblock associative copolymers by RAFT technique

Polymer Bulletin - Preparation of associating multiblock copolymer electrolytes mediated by radical addition–fragmentation chain transfer (RAFT) technique has been evaluated and reported in...     

Synthesis and Properties of New Cleavable Cationic Surfactants Containing Carbonate Groups

A novel series of cleavable alkyltrimethylammonium surfactants with different hydrocarbon chain lengths (C8–16) were synthesized. A carbonate break site inserted between the polar head and the hydrocarbon chain makes these compounds hydrolyzable. The reagents used are renewable, (bio)degradable, or reusable. The hydrolysis of these cleavable surfactants will lead to the generation of fatty alcohols and choline, which is an essential biological nutrient. The surface activities in aqueous solution of the synthesized carbonates fulfill the requirement of being good surfactants. In addition, the cleavable compounds containing n-decyl and n-dodecyl chains showed similar or higher antimicrobial activities when compared to a non-cleavable analog.     

Genome-wide effect of tetracycline,doxycycline and 4-epidoxycycline on gene expression in Saccharomyces cerevisiae

Tetracycline (Tet) and derivative chemicals (e.g., doxycycline or Dox) have gained widespread recognition for their antibiotic properties since their introduction in the late 1970s, but recent work with these chemicals in the lab has shifted to include multiple techniques in all genetic model systems for the precise control of gene expression. The most widely used Tet-modulated methodology is the Tet-On/Tet-Off gene expression system. Tet is generally considered to have effects specific to bacteria; therefore, it should have few off-target effects when used in eukaryotic systems, and a previous study in the yeast Saccharomyces cerevisiae found that Dox had no effect on genome-wide gene expression as measured by microarray. In contrast, another study found that the use of Dox in common cell lines and several model organisms led to mitonuclear protein imbalance, suggesting an inhibitory role of Dox in eukaryotic mitochondria. Recently, a new Dox derivative, 4-epidoxycycline (4-ED) was developed that was shown to have less off-target consequences on mitochondrial health. To determine the best tetracycline family chemical to use for gene expression control in S. cerevisiae, we performed RNA sequencing (RNA-seq) on yeast grown on standard medium compared with growth on media supplemented with Tet, Dox or 4-ED. We found each caused dozens of genes to change expression, with Dox eliciting the greatest expression responses, suggesting that the specific tetracycline used in experiments should be tailored to the specific gene(s) of interest when using the Tet-On/Tet-Off system to reduce the consequences of confounding off-target responses.     

Yoghurt‐type beverage with partial substitution of milk by a chickpea extract: Effect on physicochemical and flow properties

The objective of this study was to determine the evolution of physicochemical and flow properties of a yoghurt‐type beverage partially replaced with a chickpea extract over a period of 22 days. From two chickpea extracts, Blanco Noroeste was selected for its higher protein content. Six yoghurt‐type formulations were prepared, stored at 4 °C and analysed on days 1, 8, 15 and 22. pH was 4.24–4.75, while brightness was 81.7–94.5. Flow properties of the yoghurt‐type exhibited a non‐Newtonian behaviour. From three formulations that underwent sensory evaluation, the 30:70 mix obtained the highest acceptation. This yoghurt‐type beverage exhibited characteristics similar to natural yoghurt.     

Entamoeba histolyticaelectrondense granules secretion in vitro and in vivo: ultrastructural study

Electron dense granules (EDGs) were identified by transmission electron microscopy in Entamoeba histolytica trophozoites recovered from hamster liver lesions. Abundant granules were present in trophozoites recovered after 15 min of liver inoculation. Variation in the size and morphology of these EDGs was also observed. Numerous granules were present in the plasma membrane when these parasites were incubated for 5 min with MDCK monolayers. Release of these EDGs was suggested by the presence of granules in contact with the surface of the target cell plasma membrane. Parasite phagocytic invaginations were observed after 10 min of parasite-monolayer interaction. In these structures, scarce granules were seen. Granules secretion was corroborated by obtaining of a pellet of these small structures from the incubation of trophozoites with collagen supernatant. Collagenase and gellatinase activity of this pellet was identified in SDS-PAGE gels. EDGs were also present in amebic hamster liver lesions. Our observations corroborate that these granules are secreted and suggest that may participate in the cytopathic effect of E. histolytica both in vitro and in vivo.     

An evolutionary algorithm for the multi‐objective pick‐up and delivery pollution‐routing problem

The design of sustainable logistics solutions poses new challenges for the study of vehicle‐routing problems. The design of efficient systems for transporting products via a heterogeneous fleet of vehicles must consider the minimization of cost, emissions of greenhouse gases, and the ability to serve every customer within an available time slot. This phenomenon gives rise to a multi‐objective problem that considers the emission of greenhouse gases, the total traveling time, and the number of customers served. The proposed model is approached with an ε‐constraint technique that allows small instances to be solved and an evolutionary algorithm is proposed to deal with complex instances. Results for small instances show that all the points that approach the Pareto frontier found by the evolutionary algorithm are nondominated by any solution found by the multi‐objective model. For complex instances, nondominated solutions that serve most of the requests are found with low computational requirements.