O-GlcNAcylation mediates the control of cytosolic phosphoenolpyruvate carboxykinase activity via Pgc1a

PGC1a is a coactivator of many transcription factors and cytosolic phosphoenolpyruvate carboxykinase (PCK1) is a key enzyme for gluconeogenesis. PGC1a interacts with the transcription factor PPAR¿ to stimulate PCK1 expression and thus de novo glucose synthesis. These proteins are not only important for central energy metabolism but also for supplying intermediates for other metabolic pathways, including lipidogenesis and protein synthesis and might therefore be important factors in the ethiopathogenesis of metabolic disorders like diabetes but also in other pathologies like cancer. Since polymorphisms in these proteins have been related to some phenotypic traits in animals like pigs and PGC1a G482S polymorphism increases fat deposition in humans, we have investigated the molecular basis of such effects focusing on a commonly studied polymorphism in pig Pgc1a, which changes a cysteine at position 430 (WT) of the protein to a serine (C430S). Biochemical analyses show that Pgc1a WT stimulates higher expression of human PCK1 in HEK293T and HepG2 cells. Paradoxically, Pgc1a WT is less stable than Pgc1a p.C430S in HEK293T cells. However, the study of different post-translational modifications shows a higher O-GlcNAcylation level of Pgc1a p.C430S. This higher O-GlcNAcylation level significantly decreases the interaction between Pgc1a and PPAR¿ demonstrating the importance of post-translational glycosylation of PGC1a in the regulation of PCK1 activity. This, furthermore, could explain at least in part the observed epistatic effects between PGC1a and PCK1 in pigs

c.A2456C-substitution in Pck1 changes the enzyme kinetic and functional properties modifying fat distribution in pigs

Cytosolic phosphoenolpyruvate carboxykinase, PCK1, is one of the main regulatory enzymes of gluconeogenesis and glyceroneogenesis. The substitution of a single amino acid (Met139Leu) in PCK1 as a consequence of a single nucleotide polymorphism (SNP), c.A2456C, is associated in the pig to a negative phenotype characterized by reduced intramuscular fat content, enhanced backfat thickness and lower meat quality. The p.139L enzyme shows reduced k(cat) values in the glyceroneogenic direction and enhanced ones in the anaplerotic direction. Accordingly, the expression of the p.139L isoform results in about 30% lower glucose and 9% lower lipid production in cell cultures. Moreover, the ability of this isoform to be acetylated is also compromised, what would increase its susceptibility to be degraded in vivo by the ubiquitin-proteasome system. The high frequency of the c.2456C allele in modern pig breeds implies that the benefits of including c.A2456C SNP in selection programs could be considerable

Slim LSTM networks: LSTM_6 and LSTM_C6

We have shown previously that our parameter-reduced variants of Long Short-Term Memory (LSTM) Recurrent Neural Networks (RNN) are comparable in performance to the standard LSTM RNN on the MNIST dataset. In this study, we show that this is also the case for two diverse benchmark datasets, namely, the review sentiment IMDB and the 20 Newsgroup datasets. Specifically, we focus on two of the simplest variants, namely LSTM_6 (i.e., standard LSTM with three constant fixed gates) and LSTM_C6 (i.e., LSTM_6 with further reduced cell body input block). We demonstrate that these two aggressively reduced-parameter variants are competitive with the standard LSTM when hyper-parameters, e.g., learning parameter, number of hidden units and gate constants are set properly. These architectures enable speeding up training computations and hence, these networks would be more suitable for online training and inference onto portable devices with relatively limited computational resources.Comment: 6 pages, 12 figures, 5 table

Estudios In Vitro de Cementos de α-Fosfato Tricálcico Modificados con β-Silicato Dicálcico

The combination of in situ self-setting and biocompatibility, makes calcium phosphate cements highly promising materials for a wide range of clinical applications. However, its low strength limits their use only to lowstress applications. β-Dicalcium silicate (β-C2S) is a Portland cement component, able to react with water to form a hydrated phase that enhance mechanical strength of material. Different authors reported the bioactive capacity of this compound. In this investigation, α-TCP cements modified with β-C2S were prepared. The α-tricalcium phosphate (αTCP) powder was prepared through acid-base method, and β-C2S was synthesized by sol-gel method. Materials were characterized both chemically and physically. Biodegradability was studied by soaking the materials in simulated body fluid for various time periods. The results showed that a cement with 20 % of β-C2S exhibited greater compressive strength and pH values (19,8 MPa and 8,09 respectively).La capacidad que presentan los cementos de fosfato de calcio de fraguar en condiciones fisiológicas, así como su excelente biocompatibilidad, hacen estos materiales factibles para diferentes aplicaciones clínicas. Sin embargo sus bajas propiedades mecánicas limitan dichas aplicaciones a zonas de menores esfuerzos físicos. El βsilicato dicálcico (β-C2S) es un componente del cemento Portland, que reacciona con agua formando una fase hidratada de elevada resistencia mecánica. Diferentes autores han demostrado la capacidad bioactiva de este compuesto. En el presente trabajo fueron preparados cementos de α-fosfato tricálcico (α-TCP) modificados con β-C2S.El polvo de α-TCP fue obtenido por reacción ácido-base y el β-C2S vía sol-gel. Los materiales fueron caracterizados físico-químicamente, además de estudiar la biodegradación de los mismos a través de su inmersión en solución fisiológica simulada. Los mayores valores de resistencia a la compresión y pH correspondieron al cemento con 20% de β-C2S (19,8 MPa and 8,09 respectivamente

Impact of fuel quantity on luminescence properties of Sr3Al2O6:Eu by combustion synthesis

Abstract The photoluminescent behavior of Eu-doped Sr3Al2O6 obtained by highly efficient solution combustion synthesis is reported. In order to understand the influence of the fuel on the synthesis, the stoichiometric quantity and an excess of fuel were evaluated. By adjusting the amount of fuel, different luminescence responses were obtained, allowing europium cations incorporation into the Sr3Al2O6 lattice to serve as effective luminescence activators in such a short time during the rapid combustion synthesis process. The higher amount of fuel in the presence of the oxidizing agent produced Sr3Al2O6:Eu particles with higher phosphorescence brightness, owing to the increase of the reduction process from Eu3+ to Eu2+. The synthesized phosphor showed an intense band emission centered at 515 nm and could be excited over a broad spectral range in the UV-visible region. Particles having nanostructured flake-type morphology were obtained, which was considered a micro-nanofunctional candidate for practical applications

Koilocytes indicate a role for human papilloma virus in breast cancer

Background: High-risk human papilloma viruses (HPVs) are candidates as causal viruses in breast cancer. The scientific challenge is to determine whether HPVs are causal and not merely passengers or parasites. Studies of HPV-related koilocytes in breast cancer offer an opportunity to address this crucial issue. Koilocytes are epithelial cells characterised by perinuclear haloes surrounding condensed nuclei and are commonly present in cervical intraepithelial neoplasia. Koilocytosis is accepted as pathognomonic (characteristic of a particular disease) of HPV infection. The aim of this investigation is to determine whether putative koilocytes in normal and malignant breast tissues are because of HPV infection. Methods: Archival formalin-fixed normal and malignant breast specimens were investigated by histology, in situ PCR with confirmation of the findings by standard PCR and sequencing of the products, plus immunohistochemistry to identify HPV E6 oncoproteins. Results: human papilloma virus-associated koilocytes were present in normal breast skin and lobules and in the breast skin and cancer tissue of patients with ductal carcinoma in situ (DCIS) and invasive ductal carcinomas (IDCs). Interpretation: As koilocytes are known to be the precursors of some HPV-associated cervical cancer, it follows that HPVs may be causally associated with breast cancer.6 page(s

Comparison of Pharmacological Modulation of APP Metabolism in Primary Chicken Telencephalic Neurons and in a Human Neuroglioma Cell Line

Sequential cleavage of amyloid precursor protein (APP) by β- and γ-secretases and the formation of Aβ peptides are pivotal for Alzheimer's disease. Therefore, a large number of drugs has been developed targeting APP metabolism. However, many pharmacological compounds have been identified in vitro in immortalized APP overexpressing cell lines rather than in primary neurons. Here, we compared the effect of already characterized secretase inhibitors and modulators on Aβ formation in primary chicken telencephalic neurons and in a human neuroglioma cell line (H4) ectopically expressing human APP with the Swedish double mutation. Primary chicken neurons replicated the effects of a β-secretase inhibitor (β-secretase inhibitor IV), two γ-secretase inhibitors (DAPM, DAPT), two non-steroidal-anti-inflammatory drugs (sulindac sulfide, CW), and of the calpain inhibitor calpeptin. With the exception of the two γ-secretase inhibitors, all tested compounds were more efficacious in primary chicken telencephalic neurons than in the immortalized H4 cell line. Moreover, H4 cells failed to reproduce the effect of calpeptin. Hence, primary chicken telencephalic neurons represent a suitable cell culture model for testing drugs interfering with APP processing and are overall more sensitive to pharmacological interference than immortalized H4 cells ectopically expressing mutant human APP

C-Terminal Extension of the Yeast Mitochondrial DNA Polymerase Determines the Balance between Synthesis and Degradation

Saccharomyces cerevisiae mitochondrial DNA polymerase (Mip1) contains a C-terminal extension (CTE) of 279 amino acid residues. The CTE is required for mitochondrial DNA maintenance in yeast but is absent in higher eukaryotes. Here we use recombinant Mip1 C-terminal deletion mutants to investigate functional importance of the CTE. We show that partial removal of the CTE in Mip1Δ216 results in strong preference for exonucleolytic degradation rather than DNA polymerization. This disbalance in exonuclease and polymerase activities is prominent at suboptimal dNTP concentrations and in the absence of correctly pairing nucleotide. Mip1Δ216 also displays reduced ability to synthesize DNA through double-stranded regions. Full removal of the CTE in Mip1Δ279 results in complete loss of Mip1 polymerase activity, however the mutant retains its exonuclease activity. These results allow us to propose that CTE functions as a part of Mip1 polymerase domain that stabilizes the substrate primer end at the polymerase active site, and is therefore required for efficient mitochondrial DNA replication in vivo

Effects of silica addition on the chemical, mechanical and biological properties of a new α-Tricalcium Phosphate/Tricalcium Silicate Cement

The addition of tricalcium silicate (C3S) to apatite cements results in an increase of bioactivity and improvement in the mechanical properties. However, adding large amounts raises the local pH at early stages, which retards the precipitation of hydroxyapatite and produces a loss of mechanical strength. The introduction of Pozzolanic materials in cement pastes could be an effective way to reduces basicity and enhance their mechanical resistance; thus, the effect of adding silica on the chemical, mechanical and biological properties of α-tricalcium phosphate/C3S cement was studied. Adding silica produces a reduction in the early pH and a decrease in setting times; nevertheless, the presence of more calcium silicate hydrate (C-S-H) delays the growth of hydroxyapatite crystals and consequently, reduces early compressive strength. The new formulations show a good bioactivity, but higher cytotoxicity than traditional cements and additions higher than 2.5% of SiO2 cause a lack of mechanical strength and an elevated degradability