Photomixotropic and photoautotrophic micropropagation of Phytophthora resistant chestnut genotypes using liquid media.

In this study, results of photomixotropic and photoautotrophic chestnut micropropagation are compared. The aim is to increase the quality of micropropagated plants as well as to reduce costs due to plant loss during acclimatization. A successful protocol has been developed for the proliferation phase without exogenous sucrose added to the medium that has been tested with 4 genotypes. For this, shoots were exposed to decreasing sugar levels for several months to ensure their viability in sucrose-free medium. In vitro rooting in photoautotrophic conditions was applied to 15 chestnut genotypes. Every genotype formed vigorous plants which were easy to acclimatize. More than 6000 shoots were rooted with a rooting and acclimatization average value of 71% for the best treatment. This result was better than the one obtained in conventional micropropagation.Peer reviewe

Enhancing Luminescence and X‑ray Absorption Capacity of Eu3+:LaF3 Nanoparticles by Bi3+ Codoping

Bi3+ codoping has been proposed in this work with a twofold objective, namely, enhancing the luminescence emission of Eu3+:LaF3 nanoparticles (NPs) and increasing their X-ray attenuation capacity, with the purpose of obtaining a bimodal bioprobe for luminescence bioimaging and X-ray computed tomography. The synthesis method, reported here for the first time for LaF3 particles, allowed obtaining uniform, nonaggregated NPs using a homogeneous precipitation in polyol medium at room temperature in just 2 h. The simplicity of the synthesis method allows the large-scale production of NPs. LaF3 NPs with different Eu3+ contents were first synthesized to find the critical Eu3+ concentration, producing the highest emission intensity. This concentration was subsequently used to fabricate Bi3+–Eu3+-codoped LaF3 NPs using the same method. The emission intensity of the codoped NPs increased in more than one order of magnitude, thanks to the possibility of excitation through the Bi3+ → Eu3+ energy-transfer band. The luminescence properties of the codoped NPs were analyzed in detail to find the mechanism responsible for the emission enhancement. Finally, it was demonstrated that the high atomic number of Bi3+, higher than that of lanthanides, was an added value of the material because it increased its X-ray attenuation capacity. In summary, the LaF3 NPs codoped with Eu3+ and Bi3+ presented in this work are promising candidates as a bimodal bioprobe for luminescence bioimaging and X-ray computed tomography.We gratefully acknowledge T.C. Rojas for help with TEM. This work was supported by CSIC projects (PIC2016FR1 and PIE201460E005), Fondo Social Europeo-Gobierno de Aragoń and by Siemens Healthcare S.L.U. We acknowledge the use of the CNA’s ICTS NanoCT facilities.Peer reviewe

Microwave-Assisted Synthesis of Biocompatible Europium-Doped Calcium Hydroxyapatite and Fluoroapatite Luminescent Nanospindles Functionalized with Poly(acrylic acid)

Europium-doped calcium hydroxyapatite and fluoroapatite nanophosphors functionalized with poly­(acrylic acid) (PAA) have been synthesized through a one-pot microwave-assisted hydrothermal method from aqueous basic solutions containing calcium nitrate, sodium phosphate monobasic, and PAA, as well as sodium fluoride in the case of the fluoroapatite particles. In both cases a spindlelike morphology was obtained, resulting from an aggregation process of smaller subunits which also gave rise to high specific surface area. The size of the nanospindles was 191 (32) × 40 (5) nm for calcium hydroxyapatite and 152 (24) × 38 (6) nm for calcium fluoroapatite. The luminescent nanoparticles showed the typical red luminescence of Eu³⁺, which was more efficient for the fluoroapatite particles than for the hydroxyapatite. This is attributed to the presence of OH^– quenchers in the latter. The nanophosphors showed negligible toxicity for Vero cells. Both PAA-functionalized nanophosphors showed a very high (up to at least 1 week) colloidal stability in 2-(<i>N</i>-morpholino)­ethanesulfonic acid (MES) at pH 6.5, which is a commonly used buffer for physiological pH. All these features make both kinds of apatite-based nanoparticles promising tools for biomedical applications, such as luminescent biolabels and tracking devices in drug delivery systems

Ionic Liquid Mediated Synthesis and Surface Modification of Multifunctional Mesoporous Eu:GdF₃ Nanoparticles for Biomedical Applications

A procedure for the synthesis of multifunctional europium­(III)-doped gadolinium­(III) fluoride (Eu:GdF₃) nanoparticles (∼85 nm) with quasispherical shape by precipitation at 120 °C from diethylene glycol solutions containing lanthanide chlorides and an ionic liquid (1-Butyl, 2-methylimidazolium tetrafluoroborate) as fluoride source has been developed. These nanoparticles were polycrystalline and crystallized into a hexagonal structure, which is unusual for GdF₃. They were also mesoporous (pore size = 3.5 Å), having a rather high BET surface area (75 m² g^–1). The luminescent and magnetic (relaxivity) properties of the Eu:GdF₃ nanoparticles have been also evaluated in order to assess their potentiality as “in vitro” optical biolabels and contrast agent for magnetic resonance imaging. Finally, a procedure for their functionalization with aspartic-dextran polymers is also reported. The functionalized Eu:GdF₃ nanoparticles presented negligible toxicity for Vero cells, which make them suitable for biotecnological applications

Novel Proapoptotic Effect of Hepatocyte Growth Factor: Synergy with Palmitate to Cause Pancreatic β-Cell Apoptosis

Increasing evidence suggests that elevation of plasma fatty acids that often accompanies insulin resistance contributes to β-cell insufficiency in obesity-related type 2 diabetes. Circulating levels of hepatocyte growth factor (HGF) are increased in humans with metabolic syndrome and obesity. HGF is known to protect β-cells against streptozotocin and during islet engraftment. However, whether HGF is a β-cell prosurvival factor in situations of excessive lipid supply has not been deciphered. Mice overexpressing HGF in the β-cell [rat insulin type II promoter (RIP)-HGF transgenic mice] fed with standard chow display improved glucose homeostasis and increased β-cell mass and proliferation compared with normal littermates. However, after 15 wk of high-fat feeding, glucose homeostasis and β-cell expansion and proliferation are indistinguishable between normal and transgenic mice. Interestingly, RIP-HGF transgenic mouse β-cells and normal β-cells treated with HGF display increased sensitivity to palmitate-mediated apoptosis in vitro. Palmitate completely eliminates Akt and Bad phosphorylation in RIP-HGF transgenic mouse islets. HGF-overexpressing islets also show significantly decreased AMP-activated protein kinase-α and acetyl-coenzyme A carboxylase phosphorylation, diminished fatty acid oxidation, increased serine palmitoyltransferase expression, and enhanced ceramide formation compared with normal islets. Importantly, human islets overexpressing HGF also display increased β-cell apoptosis in the presence of palmitate. Treatment of both mouse and human islet cells with the de novo ceramide synthesis inhibitors myriocin and fumonisin B1 abrogates β-cell apoptosis induced by HGF and palmitate. Collectively, these studies indicate that HGF can be detrimental for β-cell survival in an environment with excessive fatty acid supply

Ligand-Free Synthesis of Tunable Size Ln:BaGdF₅ (Ln = Eu³⁺ and Nd³⁺) Nanoparticles: Luminescence, Magnetic Properties, and Biocompatibility

Bifunctional and highly uniform Ln:BaGdF₅ (Ln = Eu³⁺ and Nd³⁺) nanoparticles have been successfully synthesized using a solvothermal method consisting of the aging at 120 °C of a glycerol solution containing the corresponding Lanthanide acetylacetonates and butylmethylimidazolium tetrafluoroborate. The absence of any surfactant in the synthesis process rendered hydrophilic nanospheres (with tunable diameter from 45 nm 85 nm, depending on the cations concentration of the starting solution) which are suitable for bioapplications. The particles are bifunctional because they showed both optical and magnetic properties due to the presence of the optically active lanthanides (Eu³⁺ in the visible and Nd³⁺ in the NIR regions of the electromagnetic spectrum) and the paramagnetic gadolinium ion, respectively. The luminescence decay curves of the nanospheres doped with different amounts of Eu³⁺ and Nd³⁺ have been recorded in order to determine the optimum dopant concentration in each case, which turned out to be 5% Eu³⁺ and 0.5% Nd³⁺. Likewise, proton relaxation times were measured at 1.5 T in water suspensions of the optimum particles found in the luminescence study. The values obtained suggested that both kinds of particles could be used as positive contrast agents for MRI. Finally, it was demonstrated that both the 5% Eu³⁺ and 0.5% Nd³⁺-doped BaGdF₅ nanospheres showed negligible cytotoxicity for VERO cells for concentrations up to 0.25 mg mL^–1

Functional Characterization of Four Olive Squalene Synthases with Respect to the Squalene Content of the Virgin Olive Oil

The release of new olive cultivars with an increased squalene content in their virgin olive oil is considered an important target in olive breeding programs. In this work, the variability of the squalene content in a core collection of 36 olive cultivars was first studied, revealing two olive cultivars, 'Dokkar' and 'Klon-14', with extremely low and high squalene contents in their oils, respectively. Next, four cDNA sequences encoding squalene synthases (SQS) were cloned from olive. Sequence analysis and functional expression in bacteria confirmed that they encode squalene synthases. Transcriptional analysis in distinct olive tissues and cultivars indicated that expression levels of these four SQS genes are spatially and temporally regulated in a cultivar-dependent manner and pointed to OeSQS2 as the gene mainly involved in squalene biosynthesis in olive mesocarp and, therefore, in the olive oil. In addition, the biosynthesis of squalene appears to be transcriptionally regulated in water-stressed olive mesocarp

Rifampin Reduces Concentrations of Trimethoprim and Sulfamethoxazole in Serum in Human Immunodeficiency Virus-Infected Patients

To determine whether rifampin reduces concentrations of trimethoprim (TMP) and sulfamethoxazole (SMX) in serum of human immunodeficiency virus (HIV)-infected persons, levels of these agents were determined by high-performance liquid chromatography before and after more than 12 days of standard antituberculosis treatment for 10 patients who had been taking one double-strength tablet of co-trimoxazole once daily for more than 1 month. Statistically significant, 47 and 23% decreases in TMP and SMX mean areas under the concentration-time curve from 0 to 24 h (AUC(0–24)), respectively, were observed after administration of rifampin. N-Acetyl-SMX profiles without and with rifampin were similar. The steady-state AUC(0–24) metabolite/parent drug ratio increased by 32% with rifampin administration. Our study shows that rifampin reduces profiles of TMP and SMX in serum of HIV-infected patients

Parathyroid Hormone-Related Protein for the Treatment of Postmenopausal Osteoporosis: Defining the Maximal Tolerable Dose

Context: PTH is the only approved skeletal anabolic agent for the treatment of human osteoporosis. Unlike PTH, which is a mixed anabolic and catabolic agent, PTHrP displays features suggesting that it may be a pure anabolic agent when intermittently administered. The full dose range of PTHrP is unknown