The ceramide-activated protein phosphatase Sit4p controls lifespan, mitochondrial function and cell cycle progression by regulating hexokinase 2 phosphorylation

<p>Sit4p is the catalytic subunit of a ceramide-activated PP2A-like phosphatase that regulates cell cycle, mitochondrial function, oxidative stress resistance and chronological lifespan in yeast. In this study, we show that hexokinase 2 (Hxk2p) is hyperphosphorylated in <i>sit4</i>Δ mutants grown in glucose medium by a Snf1p-independent mechanism and Hxk2p-S15A mutation suppresses phenotypes associated with <i>SIT4</i> deletion, namely growth arrest at G1 phase, derepression of mitochondrial respiration, H₂O₂ resistance and lifespan extension. Consistently, the activation of Sit4p in <i>isc1</i>Δ mutants, which has been associated with premature aging, leads to Hxk2p hypophosphorylation, and the expression of Hxk2p-S15E increases the lifespan of <i>isc1</i>Δ cells. The overall results suggest that Hxk2p functions downstream of Sit4p in the control of cell cycle, mitochondrial function, oxidative stress resistance and chronological lifespan.</p

Photocatalytic degradation of Reactive Black 5 with TiO2-coated magnetic nanoparticles

Photocatalytic degradation of Reactive Black 5 with TiO2-coated magnetic nanoparticle

Printed Flexible μ‑Thermoelectric Device Based on Hybrid Bi₂Te₃/PVA Composites

Inorganic–polymer composites have become promising materials to be processed by printing technologies because of their unique properties that allow the fabrication of flexible wearable electronics at reduced manufacturing costs. In the present work, a complete methodological process of assembling a flexible microthermoelectric generator based on inorganic−polymer materials is presented. The used microparticles were prepared by a top-down approach beginning with a previously prepared material by solid-state reaction and later scaled down through the use of ball milling. It was found that the necessity to proceed with a chemical treatment with HCl to reduce Bi2O3 present on the surface of the microparticle leads to a power factor (PF) of 2.29 μW K–2 m–1, which is two times higher than that of the untreated sample. On the fabrication of flexible inorganic–organic thermoelectric thick films based on Bi2Te3 microparticles (<50 μm) and the poly­(vinyl alcohol) (PVA) polymer with different thicknesses ranging from 11 to 265 μm and with different Bi2Te3 weight percentages (wt %), we found that PVA allowed achieving a homogeneous dispersion of the parent inorganic thermoelectric materials, while still maintaining their high performance. The best produced ink was obtained with 25 wt % of PVA and 75 wt % of chemically treated Bi2Te3 micropowder with a Seebeck coefficient of −166 μV K–1 and a PF of 0.04 μW K–2 m–1. For this optimized concentration, a flexible thermoelectric device was fabricated using n-type thermoelectric inks, which constitutes a major advantage to be applied in printing techniques because of their low curing temperature. The device architecture was composed of 10 stripes with 0.2 × 2.5 cm2 each in a one-leg configuration. This prototype yielded a power output up to ∼9 μW cm–2 with a 46 K temperature gradient (ΔT), and the results were combined with numerical simulations showing a good match between the experimental and the numerical results. The thermoelectric devices studied in this work offer easy fabrication, flexibility, and an attractive thermoelectric output for specific power requirements such as for environmental health monitoring

Highly Monodisperse Fe₃O₄@Au Superparamagnetic Nanoparticles as Reproducible Platform for Genosensing Genetically Modified Organisms

Several routes have been developed to prepare magnetic core–shell Fe3O4@Au nanoparticles (MNPs). However, only highly monodisperse MNPs are suitable for analytical applications. Herein, we describe the detection of GMO through the use of gold-coated MNPs with fine-tuned properties as platforms. The MNPs were prepared through a procedure that involves the preparation of Fe3O4 cores by thermal decomposition and their coating through reduction of a gold precursor. Different Fe3O4:Au precursor molar ratios (1:1; 1:4; 1:7) were tested on the Fe3O4 encapsulation. Monodisperse quasi-spherical core–shell Fe3O4@Au were obtained for the 1:4 and 1:7 ratios, in contrast, the 1:1 ratio did not lead to complete encapsulation of Fe3O4 cores. Therefore, the Fe3O4@Au obtained from higher Fe3O4:HAuCl4 ratios were tested as platforms for an electrochemical genoassay to detect MON810. The best performance was achieved with the Fe3O4@Au prepared from 1:4 ratio (10.0 ± 1.7 nm). A DNA probe covalently linked to a carboxylated self-assembled monolayer and a fluorescein isothiocyanate (FITC) signaling probe were used in a sandwich assay format. Labeling with anti-FITC-peroxidase Fab fragment conjugate allowed chronoamperometric measurements of the enzyme activity captured on Fe3O4@Au placed on screen-printed electrodes upon the hybridization event. The genoassay provided a linear range from 0.25 to 2.5 nM, LOD of 0.15 nM, with a reproducibility <4%. Certified samples containing the transgenic event were measured without further purification after PCR amplification. The results highlight the efficiency of the genoassay for the MON810 detection, opening new horizons to achieve a low-cost analysis out of large laboratory facilities to verify the compliance of GMO regulations

Screen-Printed Photochromic Textiles through New Inks Based on SiO₂@naphthopyran Nanoparticles

Photochromic silica nanoparticles (SiO₂@<b>NPT</b>), fabricated through the covalent immobilization of silylated naphthopyrans (NPTs) based on 2<i>H</i>-naphtho­[1,2-<i>b</i>]­pyran (<b>S1</b>, <b>S2</b>) and 3<i>H</i>-naphtho­[2,1-<i>b</i>]­pyran (<b>S3</b>, <b>S4</b>) or through the direct adsorption of the parent naphthopyrans (<b>1</b>, <b>3</b>) onto silica nanoparticles (SiO₂ NPs), were successfully incorporated onto cotton fabrics by a screen-printing process. Two aqueous acrylic- (AC-) and polyurethane- (PU-) based inks were used as dispersing media. All textiles exhibited reversible photochromism under UV and solar irradiation, developing fast responses and intense coloration. The fabrics coated with SiO₂@<b>S1</b> and SiO₂@<b>S2</b> showed rapid color changes and high contrasts (Δ<i>E</i>*_ab = 39–52), despite presenting slower bleaching kinetics (2–3 h to fade to the original color), whereas the textiles coated with SiO₂@<b>S3</b> and SiO₂@<b>S4</b> exhibited excellent engagement between coloration and decoloration rates (coloration and fading times of 1 and 2 min, respectively; Δ<i>E</i>*_ab = 27–53). The PU-based fabrics showed excellent results during the washing fastness tests, whereas the AC-based textiles evidenced good results only when a protective transfer film was applied over the printed design

Superparamagnetic MFe₂O₄ (M = Fe, Co, Mn) Nanoparticles: Tuning the Particle Size and Magnetic Properties through a Novel One-Step Coprecipitation Route

Superparamagnetic ferrite nanoparticles (MFe₂O₄, where M = Fe, Co, Mn) were synthesized through a novel one-step aqueous coprecipitation method based on the use of a new type of alkaline agent: the alkanolamines isopropanolamine and diisopropanolamine. The role played by the bases on the particles’ size, chemical composition, and magnetic properties was investigated and compared directly with the effect of the traditional inorganic base NaOH. The novel MFe₂O₄ nanomaterials exhibited high colloidal stability, particle sizes in the range of 4–12 nm, and superparamagnetic properties. More remarkably, they presented smaller particle sizes (up to 6 times) and enhanced saturation magnetization (up to 1.3 times) relative to those prepared with NaOH. Furthermore, the nanomaterials exhibited improved magnetic properties when compared with nanoferrites of similar size synthesized by coprecipitation with other bases or by other methods reported in the literature. The alkanolamines were responsible for these achievements by acting both as alkaline agents and as complexing agents that controlled the particle size during the synthesis process and improved the spin rearrangement at the surface (thinner magnetic “dead” layers). These results open new horizons for the design of water-dispersible MFe₂O₄ nanoparticles with tuned properties through a versatile and easily scalable coprecipitation route

Naphthopyran-Based Silica Nanoparticles as New High-Performance Photoresponsive Materials

Hybrid nanomaterials based on the covalent grafting of silylated naphthopyrans (NPTs) onto silica nanoparticles (SiO₂ NPs) were successfully prepared and studied as new photochromic materials. They were prepared by a two-step protocol consisting of (i) NPTs (derivatives from 2<i>H</i>-naphtho­[1,2-b]­pyran (2<i>H</i>-NPT) and 3<i>H</i>-naphtho­[2,1-b]­pyran (3<i>H</i>-NPT)) silylation by a microwave-assisted reaction between hydroxyl-substituted NPTs and 3-(triethoxysilyl)­propyl isocyanate, followed by (ii) covalent post-grafting onto SiO₂ NPs. In order to study the role of the silylation step, the analogous non-silylated nanomaterials were also prepared by direct adsorption of NPTs. The characterization techniques confirmed the successful NPTs silylation and subsequent grafting to SiO₂ NPs. All SiO₂-based nanomaterials revealed photoswitching behavior, following a biexponential decay. The SiO₂ NPs functionalized with silylated 3<i>H</i>-NPTs (SiO₂@<b>S3</b> and SiO₂@<b>S4</b>) presented the most promising photochromic properties, showing fast coloration/decoloration kinetics (coloring in 1 min under UV irradiation and fading in only 2 min) and high values of total color difference (Δ<i>E</i>*_ab = 30–50). Also, the 2<i>H</i>-NPTs-based SiO₂ NPs (SiO₂@<b>S1</b> and SiO₂@<b>S2</b>) presented fast coloration and good color contrasts (Δ<i>E</i>*_ab = 54), but slower fading kinetic rates, taking more than 2 h to return to their initial color. In contrast, the SiO₂ NPs functionalized with non-silylated NPTs (SiO₂@<b>1</b> and SiO₂@<b>3</b>) showed weaker color contrasts (Δ<i>E</i>*_ab = 6–10) and slower fading kinetics, proving that the NPT silylation step was crucial to enhance the photochromic behavior of SiO₂ NPs based on NPTs. Furthermore, the silylated-based nanomaterials showed good photostability upon prolonged UV light exposure, keeping their photochromic performance unchanged for at least 12 successive UV/dark cycles, anticipating interesting technological applications in several areas

Differences in TG molecular species profile in logarithmic and PDS growth phases.

Distribution of the relevant molecular species of TG in logarithmic (A) and post-diauxic shift phase (B) was altered. Data is normalized against the sum of the reconstructed areas considered for each phase and presented as mean ± standard deviation of three biological replicates. Statistical analysis was performed by two-way analysis of variance (ANOVA) followed by Bonferroni's multiple comparison test (***PS5 Fig.</p

Membrane fluidity is not altered in PDS phase despite the upregulation of the Δ9 fatty acid desaturase-coding gene.

(A) Quantitative real-time PCR analysis of expression levels of OLE1 gene in logarithmic and PDS phases were assessed. Target/reference ratios were calculated using the mathematical model determined by Pfaffl (2001) [65]. Actin was used as the reference gene. Data are expressed as mean values ± standard deviation of three biological replicates. Statistical analysis was performed by one-way analysis of variance (ANOVA) followed by Dunnett's multiple comparison test (**PS. cerevisiae strains. Liposomes were prepared with PL extracts and incubated with DPH. The depicted graph represents 1n and is illustrative of the observations in two biological replicates.</p

Correlations between CD25^bright/CD4⁺ aTreg frequencies and immunoblot band numbers.

<p>A–C: Bands recognized in immunoblots of HEp2-cytoplasmic proteins by SLE patients, unaffected relatives and unrelated control subjects. D–F: Bands recognized in immunoblots of HEp2-nuclear proteins. Regression lines represent linear regression.</p