Chronic High Fat Diet Intake Impairs Hepatic Metabolic Parameters in Ovariectomized Sirt3 KO Mice

High fat diet (HFD) is an important factor in the development of metabolic diseases, with liver as metabolic center being highly exposed to its influence. However, the effect of HFD-induced metabolic stress with respect to ovary hormone depletion and sirtuin 3 (Sirt3) is not clear. Here we investigated the effect of Sirt3 in liver of ovariectomized and sham female mice upon 10 weeks of feeding with standard-fat diet (SFD) or HFD. Liver was examined by Folch, gas chromatography and lipid hydroperoxide analysis, histology and oil red staining, RT-PCR, Western blot, antioxidative enzyme and oxygen consumption analyses. In SFD-fed WT mice, ovariectomy increased Sirt3 and fatty acids synthesis, maintained mitochondrial function, and decreased levels of lipid hydroperoxides. Combination of ovariectomy and Sirt3 depletion reduced pparα, Scd-1 ratio, MUFA proportions, CII-driven respiration, and increased lipid damage. HFD compromised CII-driven respiration and activated peroxisomal ROS scavenging enzyme catalase in sham mice, whereas in combination with ovariectomy and Sirt3 depletion, increased body weight gain, expression of NAFLD- and oxidative stress-inducing genes, and impaired response of antioxidative system. Overall, this study provides evidence that protection against harmful effects of HFD in female mice is attributed to the combined effect of female sex hormones and Sirt3, thus contributing to preclinical research on possible sex-related therapeutic agents for metabolic syndrome and associated diseases.     

Antitumor Activity of Fucus vesiculosus-Derived Phlorotannins through Activation of Apoptotic Signals in Gastric and Colorectal Tumor Cell Lines

Seaweeds are one of the largest producers of biomass in the marine environment and a source of multiple bioactive metabolites with valuable health benefits. Among these, phlorotannins have been widely recognized for their promising bioactive properties. The potential antitumor capacity of Fucus vesiculosus-derived phlorotannins remains, however, poorly explored, especially in gastrointestinal tract-related tumors. Therefore, this work aimed to evaluate the cytotoxic properties and possible mechanisms by which F. vesiculosus crude extract (CRD), phlorotannin-rich extract (EtOAc), and further phlorotannin-purified fractions (F1–F9) trigger cell death on different tumor cell lines of the gastrointestinal tract, using flow cytometry. The results indicate that F. vesiculosus samples exert specific cytotoxicity against tumor cell lines without affecting the viability of normal cells. Moreover, it was found that, among the nine different phlorotannin fractions tested, F5 was the most active against both Caco-2 colorectal and MKN-28 gastric cancer cells, inducing death via activation of both apoptosis and necrosis. The UHPLC-MS analysis of this fraction revealed, among others, the presence of a compound tentatively identified as eckstolonol and another as fucofurodiphlorethol, which could be mainly responsible for the promising cytotoxic effects observed in this sample. Overall, the results herein reported contribute to a better understanding of the mechanisms behind the antitumor properties of F. vesiculosus phlorotannin-rich extracts.     

Two-Step Preparation of Benzylacetone

Two-step preparation of benzylacetone has been investigated using layered double hydroxides (LDHs) as catalysts for aldol condensation of benzaldehyde and acetone and Ni supported catalysts for consecutive hydrogenation of benzylideneacetone. Activity and selectivity of LDHs of various Mg/Al ratios to desired product, benzylideneacetone, have been compared in the liquid phase at 333 K. An aldol condensation yield at 100 % conversion of benzaldehyde was 78 % using catalyst HT-2.0. In the following, optimal hydrogenation conditions—temperature of 353 K, hydrogen pressure of 5 MPa and 5 wt% of catalyst NiSAT^® 320 were found. At 95 % conversion of benzylideneacetone the selectivity to desired product was 99 %.     

A self-optimizing mobile network: Auto-tuning the network with firefly-synchronized agents

The reduction of cost and complexity is a key driver in the evolution of mobile networks. This reduction not only applies to the pre-operational state (e.g. the deployment phase of a new network), but to the operational state as well. During the operational state, self-optimization processes can be performed to reduce the operating expenses (OPEX) of telecommunications operators. In this paper, we propose an agent-based mechanism for auto-tuning mobile networks with the aim of achieving energy savings in access networks. Firefly-based synchronization is used for the coordination of mutually dependent software agents located at the operator’s base stations. Once synchronized, agents can act together to obtain a global goal – i.e. the reduction of the telecommunications operator’s costs without reducing the quality of the provided services for mobile users. These agents build a self-organized overlay network where neither centralized nor decentralized control is needed and, therefore, is more robust.     

Encapsulation of polyphenolic antioxidants from medicinal plant extracts in alginate–chitosan system enhanced with ascorbic acid by electrostatic extrusion

In this study the encapsulation of raspberry leaf, hawthorn, ground ivy, yarrow, nettle and olive leaf extracts was performed by electrostatic extrusion in alginate-chitosan microbeads, with ascorbic acid being used for the dissolution of chitosan. The original and encapsulated plant extracts were characterized for their polyphenol content and composition, mineral content and antioxidant capacity. Raspberry leaf encapsulating microbeads exhibited the highest total phenol content and antioxidant capacity, followed by hawthorn, while olive leaf microbeads contained the lowest total phenol content. High encapsulation efficiency was obtained for all extract encapsulating microbeads (80-89%). Nettle extract-containing microparticles were characterized with the largest particle size and irregular shape, due to a high content of microelements (copper, strontium, and zinc), which affected the geling process of alginate. Although the antioxidant stability of hydrogel microcapsules was deteriorated during refrigerated storage, which might be attributed to the instability of ascorbic acid, the obtained microbeads deliver significant biological activity and antioxidant potential which may increase the daily intake of antioxidants when implemented in a food product.     

Characterisation of Acetyl‐CoA Thiolase: The First Enzyme in the Biosynthesis of Terpenic Sex Pheromone Components in the Labial Gland of Bombus terrestris

Buff‐tailed bumblebees, Bombus terrestris, use a male sex pheromone for premating communication. Its main component is a sesquiterpene, 2,3‐dihydrofarnesol. This paper reports the isolation of a thiolase (acetyl‐CoA thiolase, AACT_BT), the first enzyme involved in the biosynthetic pathway leading to formation of isoprenoids in the B. terrestris male sex pheromone. Characterisation of AACT_BT might contribute to a better understanding of pheromonogenesis in the labial gland of B. terrestris males. The protein was purified to apparent homogeneity by column chromatography with subsequent stepwise treatment. AACT_BT showed optimum acetyltransferase activity at pH 7.1 and was strongly inhibited by iodoacetamide. The enzyme migrated as a band with an apparent mass of 42.9 kDa on SDS‐PAGE. MS analysis of an AACT_BT tryptic digest revealed high homology to representatives of the thiolase family. AACT_BT has 96 % amino acid sequence identity with the previously reported Bombus impatiens thiolase.     

A mechanism of interaction of copper with a deoxygenated neutral aqueous solution

The electrochemical behaviour of Cu exposed to deoxygenated borate buffer for 330 h was characterised by chronopotentiometry, voltammetry, electrochemical impedance spectroscopy and cupric ion-selective electrode measurements. The results were interpreted by a quantitative kinetic model of the copper/electrolyte interface featuring two adsorbed intermediates produced by interaction of Cu with adsorbed water and electrochemical reduction of soluble divalent copper. The model reproduces successfully both the current vs. potential curve and the electrochemical impedance spectra around the open-circuit potential. On the basis of the experimental and calculation results, tentative conclusions for the interplay between hydrogen generation and copper corrosion are drawn.     

The transpassive dissolution mechanism of highly alloyed stainless steels: II. Effect of pH and solution anion on the kinetics

The transpassive dissolution of austenitic stainless steels (AISI 316L, AISI 904L, 254SMO and 654SMO) in a 0.5 M sulphate solution with pH 2 was studied by conventional and rotating ring–disc voltammetry, as well as electrochemical impedance spectroscopy. The main process in the transpassive potential region was found to be the release of soluble Cr(VI), while small amounts of lower-valency Cr or Mo species are released as well. Secondary passivation readily occurs for AISI 316L, whereas the remaining highly alloyed steels dissolve at high current densities in the whole potential range studied. The dissolution rate was found to increase in the order AISI 904L<254SMO<654SMO. Thus it can be correlated to the increase in the Cr and especially Mo content of the steel substrate. The impedance spectra contain contributions from the transpassive dissolution of Cr and secondary passivation, probably due to enrichment of Fe in the outermost layer of the surface film. A kinetic model of the process is proposed, including a two-step transpassive dissolution of Cr via a Cr(VI) intermediate and the dissolution of Fe(III) through the anodic film. The model was found to be in quantitative agreement with steady state current vs. potential curves and electrochemical impedance spectra. The kinetic parameters of transpassive dissolution were determined and the relevance of their values is discussed.