191 research outputs found

    Laccase gene silencing negatively effects growth and development in Pleurotus ostreatus

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    42-51In this study we describe the effects of Pleurotus ostreatus transformants that have been silenced for laccase genes. Using the RNAi strategy, transformants with different levels of phenotypic alteration were obtained with respect to their oxidation capacity of 2,6-dimethoxyphenol (DMP). The analysis of laccase activity on DMP allowed us to select transformants with severe, medium and light phenotypic alteration in comparison to the PoB strain. The measurements of the average growth rate of the transformants with severe phenotypic alteration suggested that laccase expression could play a role in the vegetative growth of P. ostreatus. It was observed that both in solid and liquid cultures, PoB and the transformants express mRNA for lacc10, although the transformants with medium and severe phenotypic alteration present a decrease in intensity, especially in solid culture. This suggests that the product of this gene is responsible for the development of the mycelium and probably participates in the production of biomass in solid culture and also could be related to the decrease in the intensity of the constant isoenzyme observed in both culture systems

    Structural stabilization of botulinum neurotoxins by tyrosine phosphorylation

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    AbstractTyrosine phosphorylation of botulinum neurotoxins augments their proteolytic activity and thermal stability, suggesting a substantial modification of the global protein conformation. We used Fourier-transform infrared (FTIR) spectroscopy to study changes of secondary structure and thermostability of tyrosine phosphorylated botulinum neurotoxins A (BoNT A) and E (BoNT E). Changes in the conformationally-sensitive amide I band upon phosphorylation indicated an increase of the α-helical content with a concomitant decrease of less ordered structures such as turns and random coils, and without changes in β-sheet content. These changes in secondary structure were accompanied by an increase in the residual amide II absorbance band remaining upon H-D exchange, consistent with a tighter packing of the phosphorylated proteins. FTIR and differential scanning calorimetry (DSC) analyses of the denaturation process show that phosphorylated neurotoxins denature at temperatures higher than those required by non-phosphorylated species. These findings indicate that tyrosine phosphorylation induced a transition to higher order and that the more compact structure presumably imparts to the phosphorylated neurotoxins the higher catalytic activity and thermostability

    1,3-diphenylpropan-1-ones as allosteric modulators of α7 nACh receptors with analgesic and antioxidant properties

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    Nicotine acethylcholine receptors (nAChRs) play critical roles in cognitive processes, neuroprotection and inflammation. Results: According to their substituents, 1,3-diphenylpropan-1-one derivatives act as α7 nAChRs negative allosteric modulators (NAM, OMe) or Type I positive allosteric modulators (PAMs, OH). Compounds 7 and 31 were the most effective (989 and 666% enhancement of ACh-induced currents) and potent (EC: 12.9 and 6.85 μM) PAMs. They exhibited strong radical scavenging values. Compound 31, selective over other neuronal nAChR subtypes and with acceptable pharmacokinetic profile, showed antinociceptive effects in a model of inflammatory pain. Conclusion: Compound 31 is a novel, potent and selective α7 nAChR PAM, displaying antioxidant and analgesic activities. The 1,3-diphenylpropan-1-one scaffold could be the base toward more advanced type I PAMs for the treatment of nAChR-mediated diseases.This work was supported by the Spanish MINECO: CSD2008-00005, The Spanish Ion Channel Initiative-CONSOLIDER INGENIO 2010, SAF2011-22802 and BFU2012-39092-C02. The Instituto de Neurociencias is a “Centre of Excellence Severo Ochoa”. We thank Susana Cámara Garrido for her assistance in the synthesis of some starting compounds and Susana Gerber for technical assistance. BBP thanks the CSIC for a predoctoral fellowship (JAE-Predoc from Junta para la Ampliación de Estudios, co-financed by FSE). Alpha7 nAChRPeer Reviewe

    Plasma levels of mitochondrial and nuclear DNA in patients with massive pulmonary embolism in the emergency department: A prospective cohort study

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    Introduction: Cell-free plasma mitochondrial DNA (mt-DNA) and nuclear DNA (n-DNA) are biomarkers with prognostic utility in conditions associated with a high rate of cell death. This exploratory study aimed to determine the plasma levels of both nucleic acids in patients with massive and submassive pulmonary embolism (PE) and to compare them with other biomarkers, such as heart-type fatty acid-binding protein (H-FABP) and troponin I (Tn-I) Methods: This was a prospective observational study of 37 consecutive patients with massive PE, 37 patients with submassive PE, and 37 healthy subjects. Quantifications of plasma mt-DNA and n-DNA with real-time quantitative polymerase chain reaction (PCR), and plasma H-FABP and Tn-I by commercial assays, were done on blood samples drawn within 4 hours after presentation at the emergency department. Results: Plasma mt-DNA and n-DNA concentrations were much higher in patients with massive PE (median, 2,970 GE/ml; interquartile range (IQR), 1,050 to 5,485; and 3,325 GE/ml, IQR: 1,080 to 5,790, respectively) than in patients with submassive PE (870 GE/ml and 1,245 GE/ml, respectively; P < 0.01) or controls (185 GE/ml and 520 GE/ml, respectively). Eighteen patients with massive PE died of a PE-related cause by day 15 of observation. Plasma mt- DNA and n-DNA values were 2.3-fold and 1.9-fold higher in the subgroup of nonsurviving patients than in survivors. H-FABP and Tn-I values were also higher in patients with massive PE who died (7.3 ng/ml and 0.023 ng/ml, respectively) than in those who survived (6.4 ng/ml, and 0.016 ng/ml, respectively). By receiver operating curve (ROC) analysis, the best cutoff values for predicting 15-day mortality were 3,380 GE/ml for mt-DNA, 6.8 ng/ml for H-FABP, 3,625 GE/ml for n-DNA, and 0.020 ng/ml for Tn-I, based on the calculated areas under the curve (AUCs) of 0.89 (95% confidence interval (CI), 0.78 to 0.99), 0.76 (95% CI, 0.69 to 093), 0.73 (95% CI, 0.58 to 0.91), and 0.59 (95% CI, 0.41 to 0.79), respectively. By stepwise logistic regression, a plasma mt-DNA concentration greater than 3,380 GE/ml (adjusted odds ratio (OR), 8.22; 95% CI, 1.72 to 39.18; P 6.8 ng/ml (OR, 5.36; 95% CI, 1.06 to 27.08; P < 0.01) were the only independent predictors of mortality. Conclusions: mt-DNA and H-FBAP might be promising markers for predicting 15-day mortality in massive PE, with mt-DNA having better prognostic accuracy.This work was supported partially by grants from Plan Nacional I+D+I (SAF 2008-05347 and SAF2011-23575) and from Fundación Mutua Madrileña de Investigación Biomédica (2008 and 2011) to Francisco Arnalich and Carmen Montie

    Generation of Molecular Diversity from Amino Acids. A Source for the Discovery of New TRP Channel Modulators

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    Trabajo presentado en el IV RECI: New Horizons in Ion Channel Research, celebrado en Cuenca (España) del 12 al 13 de febrero de 2013.Ion channels are central and challenging targets in medicinal chemistry but, because of the scarce structural knowledge, rational approaches to ion channel modulators are still rare. Moreover, the multimodal activation of some channels, like TRPs, complicates still more the scenario for rational discovery programs. Due to these facts, most strategies directed to identify ion channel modulators rely on the screening of peptide and small-molecule libraries. In this context, we have been involved in the development of synthetic pathways for the generation of diverse, chiral, highly functionalized linear and heterocyclic scaffolds from amino acids, and in the production of discrete libraries from them. The screening of these libraries on different TRP channels has allowed the discovery of some innovative hits that have progressed to hit-to-lead optimization programs. This communication will deal with the synthesis, structural characterization, and biological evaluation of a collection of β,γ–diaminoester derivatives that display significant activity at TRPV1, TRPM8 and TRPA1 channels. Compound RGM04-7, a selective.Supported by MICINN grants: Consolider-Ingenio 2010 (CSD2008-00005 and CSD2006-00015), SAF2009-09323 and BFU2009-08346, and the Generalitat Valenciana (PROMETEO/2010/046)

    Long-term CO₂ injection and its impact on near-surface soil microbiology

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    Impacts of long-term CO₂ exposure on environmental processes and microbial populations of near-surface soils are poorly understood. This near-surface long-term CO₂ injection study demonstrated that soil microbiology and geochemistry is influenced more by seasonal parameters than elevated CO₂. Soil samples were taken during a 3-year field experiment including sampling campaigns before, during and after 24 months of continuous CO₂ injection. CO₂ concentrations within CO₂-injected plots increased up to 23% during the injection period. No CO₂ impacts on geochemistry were detected over time. In addition, CO₂ exposed samples did not show significant changes in microbial CO₂ and CH₄ turnover rates compared to reference samples. Likewise, no significant CO₂-induced variations were detected for the abundance of Bacteria, Archaea (16S rDNA) and gene copy numbers of the mcrA gene, Crenarchaeota and amoA gene. The majority (75%–95%) of the bacterial sequences were assigned to five phyla: Firmicutes, Proteobacteria, Actinobacteria, Acidobacteria and Bacteroidetes. The majority of the archaeal sequences (85%–100%) were assigned to the thaumarchaeotal cluster I.1b (soil group). Univariate and multivariate statistical as well as principal component analyses showed no significant CO₂-induced variation. Instead, seasonal impacts especially temperature and precipitation were detected

    Spanish ATLAS tier-2: Facing up to LHC Run 2

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    The goal of this work is to describe the way of addressing the main challenges of Run 2 by the Spanish ATLAS Tier-2. The considerable increase of energy and luminosity for the upcoming Run 2 with respect to Run 1 has led to a revision of the ATLAS computing model as well as some of the main ATLAS computing tools. In this paper, the adaptation to these changes will be described. The Spanish ATLAS Tier-2 is a R&D project which consists of a distributed infrastructure composed of three sites and its members are involved in ATLAS computing progress, namely the work in different tasks and the development of new tools (e.g. Event Index)This work has been supported by MINECO, Spain (Proj. Ref. FPA2010-21919-C03-01,02,03 & FPA2013-47424-C3,01,02,03), which include FEDER funds from the European Unio

    DD04107-Derived neuronal exocytosis inhibitor peptides: Evidences for synaptotagmin-1 as a putative target

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    The analgesic peptide DD04107 (Pal-EEMQRR-NH2) and its acetylated analogue inhibit a-calcitonin gene-related peptide (a-CGRP) exocytotic release from primary sensory neurons. Examining the crystal structure of the SNARE-Synaptotagmin-1(Syt1) complex, we hypothesized that these peptides could inhibit neuronal exocytosis by binding to Syt1, hampering at least partially its interaction with the SNARE complex. To address this hypothesis, we first interrogate the role of individual side-chains on the inhibition of a-CGRP release, finding that E1, M3, Q4 and R6 residues were crucial for activity. CD and NMR conformational analysis showed that linear peptides have tendency to adopt a-helical conformations, but the results with cyclic analogues indicated that this secondary structure is not needed for activity. Isothermal titration calorimetry (ITC) measurements demonstrate a direct interaction of some of these peptides with Syt1-C2B domain, but not with Syt7-C2B region, indicating selectivity. As expected for a compound able to inhibit a-CGRP release, cyclic peptide derivative Pal-E-cyclo[EMQK]R-NH2 showed potent in vivo analgesic activity, in a model of inflammatory pain. Molecular dynamics simulations provided a model consistent with KD values for the interaction of peptides with Syt1-C2B domain, and with their biological activity. Altogether, these results identify Syt1 as a potential new analgesic target. © 202
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