Probing the Azaaurone Scaffold against the Hepatic and Erythrocytic Stages of Malaria Parasites

The potential of azaaurones as dual‐stage antimalarial agents was investigated by assessing the effect of a small library of azaaurones on the inhibition of liver and intraerythrocytic lifecycle stages of the malaria parasite. The whole series was screened against the blood stage of a chloroquine‐resistant Plasmodium falciparum strain and the liver stage of P. berghei, yielding compounds with dual‐stage activity and sub‐micromolar potency against erythrocytic parasites. Studies with genetically modified parasites, using a phenotypic assay based on the P. falciparum Dd2‐ScDHODH line, which expresses yeast dihydroorotate dehydrogenase (DHODH), showed that one of the azaaurone derivatives has the potential to inhibit the parasite mitochondrial electron‐transport chain. The global urgency in finding new therapies for malaria, especially against the underexplored liver stage, associated with chemical tractability of azaaurones, warrants further development of this chemotype. Overall, these results emphasize the azaaurone chemotype as a promising scaffold for dual‐stage antimalarials.     

Versatile Thermochromic Supramolecular Materials Based on Competing Charge Transfer Interactions

Stimuli‐responsive supramolecular materials are of paramount importance for a broad range of applications. It is essential to impart versatility, sustainability, and scalability into these materials. Herein the authors report the design and synthesis of a new class of thermochromic supramolecular materials, which can easily be processed from water via a reversible sol–gel transition. The supramolecular materials are composed of a bis‐bipyridinium acceptor, a π‐electron‐rich naphthalene derivative donor, and halogen counterions. Long helical nanofibers can be assembled in water, gelating at room temperature. Inked designs, thin films, and aerogels are solution‐processed to exhibit thermochromic behavior based on competing π → π* and n → π* charge transfer interactions. By using different π‐electron rich donors, and counterions, the authors demonstrate that both the color observed at room temperature and at high temperatures can be tailored. The results open up the door to develop novel amphiphile‐based thermochromes with water processability and a large tunable color palette.     

Water-transport in outer micro-porous layers for direct methanol fuel cells

The outer micro-porous layer (MPL) between the gas diffusion layer and channel of the bipolar plate was studied for both sides of the electrodes in DMFC, with particular attention to the effects of the hydrophobicity of the MPL on mass transport as well as cell performance. Water-transport behavior from the electrodes to the channel was observed through the transparent window of the single cell with membrane-electrode assemblies (MEAs) including three combinations of outer MPLs. The crossover amount of methanol as well as water through the membrane was measured, and the mass balance, based on the measured flux, was established to understand the mass transport in MEAs. The design of outer MPLs is discussed for the best cell performance.     

Mechanisms Underlying the Anti-Aging and Anti-Tumor Effects of Lithocholic Bile Acid

Bile acids are cholesterol-derived bioactive lipids that play essential roles in the maintenance of a heathy lifespan. These amphipathic molecules with detergent-like properties display numerous beneficial effects on various longevity- and healthspan-promoting processes in evolutionarily distant organisms. Recent studies revealed that lithocholic bile acid not only causes a considerable lifespan extension in yeast, but also exhibits a substantial cytotoxic effect in cultured cancer cells derived from different tissues and organisms. The molecular and cellular mechanisms underlying the robust anti-aging and anti-tumor effects of lithocholic acid have emerged. This review summarizes the current knowledge of these mechanisms, outlines the most important unanswered questions and suggests directions for future research.     

Effects of Lactic Acid Bacteria and Fermented Milks on Eicosanoid Production by Intestinal Epithelial Cells

ABSTRACT: Fermented milk products produced with probiotic lactic acid bacteria (LAB) have attracted interest due to their potential health benefits. Probiotic bacteria have a range of immunomodulatory activity, interacting with a variety of cell types in the immune system. Interactions with intestinal epithelial cells (IEC) are an avenue through which probiotics and their fermented milks can influence production of key immunoregulatory molecules, including cytokines and eicosanoids. The eicosanoids, which include the prostaglandins (PGs), are lipid mediators implicated in both acute and chronic inflammatory processes. The primary objective of this study was to determine the ability of probiotic LAB and their ferments to interact with IEC and influence their eicosanoid production. Effects of LAB and their milk ferments on prostaglandin E₂ (PGE₂) and prostaglandin F_2α (PGF_2α) production by human IEC lines were determined using a competitive enzyme immunoassay. LAB alone did not alter interleukin (IL)-1β-induced prostaglandin production by IEC. However, milk fermented with Lac-tobacillus (L.) rhamnosus strain R0011 significantly suppressed IL-1β-induced levels of PGE₂ and PGF_2α, an effect which was counteracted by the addition of strain R0011. Milk ferments prepared withL. acidophilus strain R0052 were less effective in down-regulation of PG production by IEC. Naltrexone, an opioid receptor antagonist, blocked the suppressive effects of L. rhamnosus R0011 milk ferments on PGF_2α production by IEC, suggesting that the bioactivity the ferments is opioid receptor-mediated. These findings support immunomodulatory potential of fermented food components through interactions with intestinal epithelial cells.     

EXPRESSION OF THE STA2 GLUCOAMYLASE GENE OF SACCHAROMYCES CEREVISIAE IN BREWERS' YEAST

Two fragments of DNA containing the Saccharomyces cerevisiae STA2 glucoamylase gene, with differing lengths of 5î non-coding DNA, were separately subcloned into a yeast centromeric plasmid. Of these two subclones, only the shorter one (containing 127 base-pairs of 5î non-coding DNA) was able to confer glucoamylase production on a standard laboratory strain of S. cerevisiae. The longer subclone (containing 465 bp of 5î non-coding DNA) did, however, confer glucoamylase production on a strain of S. cerevisiae lacking a functional STA10 gene (which encodes a repressor of STA2 gene expression). All-yeast plasmids lacking bacterial DNA were constructed from the two STA2 subclones for the transformation of a lager brewing yeast. Only the shorter STA2 subclone conferred glucoamylase activity on this yeast. The level of enzyme activity was comparable to that produced by the same yeast strain containing STA2 expressed from the PGK1 (that is, PGK1) promoter.     

Cider Apple Native Microbiota Characterization by PCR‐DGGE

The surface microbiota of different recognized apple varieties used to elaborate a Protected Designation of Origin cider was studied to analyse the microbial diversity and its potential link to the microorganisms involved in the cider fermentation process. The V3 region of the bacterial 16S gene and the D1 domain of the eukaryotic 26S gene were amplified by polymerase chain reaction (PCR) and analysed by denaturing gradient gel electrophoresis (DGGE). The most intense bands found in the DGGE profiles were sequenced and compared with those in the GenBank database. The profiles showed a high microbial diversity, but little variation was found among the varieties. Identification of the bands showed that the usual species associated with an apple juice fermentation were not found, suggesting that the microorganisms responsible for spontaneous fermentation come from the equipment and the production environment. Copyright © 2015 The Institute of Brewing & Distilling     

Effect of γ-irradiation on some physicochemical and thermal properties of cowpea (Vigna unguiculata L. Walp) starch

Previously, we reported that starch-related functional properties of cowpea flours and pastes were modified by 2, 10 and 50 kGy γ-irradiation doses. To elucidate some of the effects of γ-irradiation specifically on cowpea starch as well as the actual contribution of starch to the observed functional modifications at the flour and paste level, starch was isolated from irradiated cowpea flours and pastes and studied using differential scanning calorimetry (DSC), scanning electron microscopy (SEM), Fourier Transform Infra-Red (FTIR) spectroscopy, Rapid Visco-Analyser (RVA) pasting properties, and some functional properties. Pasting (peak, trough, breakdown, final, and setback viscosities) and swelling properties were significantly decreased in a dose-dependent manner. DSC of cowpea starch showed increases in peak gelatinisation temperature with increasing irradiation dose. SEM (2500×) microphotographs showed that up to 50 kGy irradiation did not present any visible physical effect on the cowpea starch granule. FTIR indicated that starch granule surface order (crystallinity) was not affected by the irradiation doses employed.