Volatile Organic Compounds of Marine Sponge Petrosia ficiformis from the Adriatic Sea

Volatile organic compounds (VOCs) of Petrosia ficiformis were investigated for the first time. The VOCs from fresh and air-dried sponge were obtained by hydrodistillation and headspace-solid phase microextraction and they were analysed by coupled gas chromatography-mass spectrometry. Aliphatic compounds with octan-3-one (up to 24.02 %), oct-1-en-3-ol (up to 8.65 %) and heptadecane (up to 39.37 %) were the most abundant in the fresh sponge along with benzaldehyde (up to 18.59 %) and diisobutyl phthalate (up to 8.44 %). Higher percentage of N,N-dimethylmethanamine (up to 19.08 %) was found in dried sample headspace and the loss of octan-3-one and benzaldehyde and increase of benzyl alcohol (up to 18.90 %) were noted. The great difference among the fresh and dried sponge VOCs obtained by hydrodistillation was noticed for fatty acids and derivatives abundance and 1H-indole increased (up to 6.00 %) in the dried sponge. Both methods enabled obtaining more complete VOCs profile and drying significantly changed their composition

Biological niches within human calcified aortic valves. Towards understanding of the pathological biomineralization process

Despite recent advances, mineralization site, its microarchitecture, and composition in calcific heart valve remain poorly understood. A multiscale investigation, using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectrometry (EDS), from micrometre up to nanometre, was conducted on human severely calcified aortic and mitral valves, to provide new insights into calcificationp rocess. Our aim was to evaluate the spatial relationship existing between bioapatite crystals, their local growing microenvironment, and the presence of a hierarchical architecture. Here we detected the presence of bioapatite crystals in two different mineralization sites that suggest the action of two different growth processes:a pathological crystallization process that occurs in biological niches and is ascribed to a purely physicochemical process and a matrix- mediated mineralized process in which the extracellular matrix acts as the template for a site-directed nanocrystals nucleation. Different shapes of bioapatite crystallization were observed at micrometer scale in each microenvironment but at the nanoscale level crystals appear to be made up by the same subunit

Crystal structure of afghanite, the eight-layer member of the cancrinite-group: Evidence for long-range Si,Al ordering

Afghanite, ideally [(Na,K)(22)Ca-10][Si24Al24O96](SO4)(6)Cl-6, is the eight-layer member of the cancrinite-group (ABABACAC stacking sequence). Its structure was refined in the P31c space group to R = 4.5% by means of single-crystal X-ray diffraction data. The cell parameters are a = 12.8013(7) Angstrom, c = 21.4119(18) Angstrom. The P6(3)mc space group proposed in a previous structure refinement is not consistent with the ordered Si,AI pattern suggested by an Si/Al ratio equal to 1 shown by afghanite and other members of the cancrinite-group. The Si-O and Al-O bond distances, 1.61(2) Angstrom and 1.72(2) Angstrom respectively, found in the structure refinement, are in accordance with an ordered Si,AI distribution which is allowed by the P31c space group, a maximal non isomorphic subgroup of P6(3)mc. Afghanite contains six 11-hedra (cancrinite) cages and two 23-hedra (liottite) cages. Four cancrinite cages are stacked along [0 0 z]. They contain a regular....Ca-Cl-Ca-Cl.... chain similar to that observed in davyne and related phases: in particular Ca is located near the center of the bases whereas Cl is near the center of the cage. A liottite cage with a base-sharing cancrinite cage is stacked along [2/3 1/3 z] and [1/3 2/3 z]. The liottite cage hosts a maximum of three sulphate groups which alternate regularly with cation-containing planes. The cancrinite cage, that shares the bases with the liottite cages, presents a disordered distribution of Cl and F reading to two possible configurations similar to those observed in liottite

Membrane protein remodeling in microglia exposed to amyloid peptides

Infection, neurodegeneration, and other conditions associated with loss of brain homeostasis, induce changes in microglial morphology, gene expression and function, generally referred to as “activation”. Alzheimer’s disease (AD) is the most common dementia and is characterized by neuroinfammatory changes, including alterations in the morphology and distribution of microglia and astrocytes, and deposition of complement and other infammatory mediators. Our previous observations show that microglial cells challenged in vitro with amyloid peptides clustered and rounded up, dramatically changing their morphology. Besides, in these cells we observed the early acetylation and then the phosphorylation of STAT3 which is required for the expression of the epsilon isoform of 14-3-3, a marker of Abeta-activated microglia (1, 2). We applied afnity partitioning approach combined with high throughput mass spectrometric analysis in order to identify variation of proteins on plasma membrane of BV2 immortalized microglia upon treatment with amyloid peptides. By this method several proteins up- or down-regulated by amyloid treatment were identifed in microglial plasma membrane. Among them annexins (5 and 7), IFITM3 and MARK3. These data have been confrmed in primary microglial cultures. In microglia, plasma membrane plays a relevant role in the cross-talking with the external neuronal environment and in the resulting trophic or infammatory response of these sentinel cells. As such, knowledge of the microglia responsiveness to beta amyloids in term of changes in its plasma membrane proteome is imperative for unveiling the molecular landscape in which AD occurs

GeoGebra se conecta a la igualdad

El constante desarrollo de las actuales tecnologías de la información y la comunicación (TIC) permite la aplicación de nuevos métodos y modelos educacionales, lo que hace necesario un esfuerzo de innovación pedagógica;  en concordancia con la Ley de Educación Nacional N° 26206 que establece como uno de los fines y objetivos de la política educativa nacional “desarrollar las competencias necesarias para el manejo de los nuevos lenguajes producidos por las tecnologías de la información y comunicación”. La distribución masiva de netbooks a alumnos y docentes de escuelas públicas, a  través del Programa Conectar Igualdad, trajo aparejado un cambio en las prácticas docentes. En nuestra región, se evidenció carencia de conocimientos y de recursos didácticos con orientaciones específicas referidas al software GeoGebra. En este sentido la Universidad Nacional del Chaco Austral,  a través del Programa de Capacitación Docente “Escuela Abierta 2010-2011”, perteneciente al Ministerio de  Educación, Ciencia y Tecnología  de la Provincia del Chaco y  del Programa Nacional de Voluntariado Universitario Convocatoria Especifica  2011 “La Universidad se conecta con la Igualdad. Universidad y Escuela Secundaria 2.0.”, contribuye a mejorar la enseñanza de matemática, promoviendo la incorporación del uso de las TIC a la cultura escolar. Por tal motivo se realizaron talleres, seminarios y cursos, fomentando en los docentes  la capacidad de desarrollar propuestas áulicas con el uso del software GeoGebra, acercando de esta manera a profesores y alumnos al mundo de la geometría dinámica, promoviendo metodologías de trabajo participativas, personalizadas y motivadoras, capaces de desarrollar materiales didácticos útiles, sencillos y atractivos, logrando captar un mayor interés de los alumnos hacia  la matemática.          

Protease-activated receptor-1 in Schwann cells and its possible role in the regeneration of peripheral nerves

Protease-activated receptor-1 (PAR-1) is the prototypic member of a family of four G-protein-coupled receptors that signal in response to extracellular proteases. In the peripheral nervous system, the expression and/or the role of PARs are still poorly investigated. High PAR-1 mRNA expression was found in the rat dorsal root ganglia and the signal intensity of PAR-1 mRNA increased in response to sciatic nerve transection, both in the proximal and in the distal part of the lesioned nerve (1). Other authors revealed that functional PAR-1 receptor exists specifically in the non-compacted Schwann cell myelin microvilli at the nodes of Ranvier in the sciatic nerve (2). Schwann cells are the principal population of glial cells of the peripheral nervous system which myelinate axons playing an important role during axonal regeneration and remyelination (3). The present study was aimed to determine if the activation of PAR-1 affects the neurotrophic properties of Schwann cells. We observed a specific staining for PAR-1 in Schwann cells of rat sciatic nerve and also in primary Schwann cell cultures. To study the role of PAR-1 in Schwann cell cultures, we activated this receptor with a specific activating peptide (PAR-1 AP). Conditioned medium from PAR-1 AP-treated Schwann cells reduced the LDH release of PC12 cells respect to the medium of the untreated cells, suggesting that the stimulation of PAR-1 induces the production of pro-survival molecules. Also an increased neurite outgrowth on PC12 cells was observed using the conditioned medium from Schwann cells treated with PAR-1 AP respect to the control obtained from untreated cells. The synthesis and secretion of several factors produced by Schwann cells treated with PAR-1 AP were investigated by proteomics, western blot and RT-PCR analyses. By these experiments we identified as putative neurotrophic candidates some molecules, such as Macrophage migration inhibitory factor, Syndecan 4 and Annexin A2

PAR-1 activation affects the neurotrophic properties of rat Schwann cells

PAR-1 (Protease-activated receptor–1) is a G-protein-coupled receptor that elicits cellular responses to extracellular proteases such as thrombin. In the peripheral nervous system (PNS), the expression and/or the role of PAR-1 are still poorly investigated. Several authors speculated that many functions in PNS, such as motor, secretory, vascular, nociceptive, inflammatory or regenerative processes, may be regulated by PARs (Vergnolle et al. 2003; Shavit et al., 2008; Wang et al., 2013). The present study was aimed to determine if PAR-1 activation affects neurotrophic properties of Schwann cells. By double immunofluorescence experiments we observed a specific staining for PAR-1 in S100β-positive cells of rat sciatic nerve and sciatic teased fibres. Moreover, PAR-1 was highly expressed in Schwann cell cultures obtained from both neonatal and adult rat sciatic nerves. When PAR-1 specific agonists were added to these cultures a higher proliferation rate was observed. Moreover, conditioned medium from primary Schwann cells treated with PAR-1 agonists increased cell survival and neurite outgrowth of PC12 cells. Therefore synthesis and secretion of several factors by Schwann cells treated with PAR-1 agonist peptides were investigated by RT-PCR, western blot and proteomics analysis. By these experiments some molecules, including extracellular matrix components and adhesion molecules, were identified as putative neurotrophic candidates

A multi-scale investigation of biological niches within human calcified aortic valves helps to understand the pathological biomineralization process

Calcific aortic valve stenosis (CAVS) is the most common form of heart valve disease in the industrialized countries, being an important public health problem [1]. Ectopic calcifications within aortic valve leaflets are strictly associated with CAVS, interfering with cusps opening, they lead to ventricular outflow obstruction [2]. Up to date no proven medical therapy stops CAVS course progression, so valve replacement is the only possible treatment of severe CAVS. Unfortunately, the degenerative valve calcification process, affects also bioprosthetic implants [3]. Being the molecular mechanisms leading to valve calcification still not understood, our aim was to carry on a multi-scale investigation using Scanning Electron Microscopy, Transmission Electron Microscopy and Energy Dispersive X-ray Spectrometry, to provide new insights into calcification process. Severely calcified aortic (tricuspid type, n = 29; bicuspid type, n = 3) and mitral valves (n = 4) were obtained from patients of both sexes (males=25) and different ages (mean age 72±10, range 41-90 years old) undergoing valve replacement due to severe aortic and mitral valve stenosis. We detected bioapatite crystals in two different mineralization sites: niches and extracellular matrix. This suggests the action of two different growth processes: the first occurs in biological niches and it is ascribed to a purely physico-chemical process; the second has the extracellular matrix acting ass the template for a site-directed nanocrystals nucleation. Different shapes of bioapatite crystallization were observed at micrometer scale in each microenvironment but at the nanoscale level crystals appear made up by the same subunits. We suggest that bioapatite nanocrystals in heart valve may activate a strong inflammatory process leading to irreversible pathological condition that, once activated,may aggravate the inflammatory response against bioapatite nanocrystals leading to a severe calcification process

FE-SEM and VP-SEM imaging of human calcified aortic valves: conventional vs Ionic Liquid innovative techniques

Conventional FE-SEM protocol for calcified aortic valves (CAVs) consist of following steps: glutaraldehyde fixation, OsO4 post-fixation, dehydration in alcohol series, critical point drying and finally sputter coating. CAVs can be observed in their native state (fixed in glutaraldehyde with and without post-fixation in OsO4) by Variable Pressure-SEM (range 6- 650 Pa). Gas presence allows an inferior resolution (low signal to noise ratio), however there is the possibility to perform EDS elemental analysis without background noise due to sputter coating. Recently Ionic liquids (IL, salts in the liquid state at room temperature) were used as suppliers of electronic conductivity with insulating properties, so we have tested their ability to replace sputter coating on CAVs in high vacuum condition. Samples fixed in glutharaldehyde 2,5% in PBS with and without OsO4 post-fixation treated with ionic liquid (Hitachi HILEM® IL 1000) were compared with samples treated with conventional FE-SEM procedures. Several IL concentration (range from 5% to 20%) were tested, different operating voltages (range from 3 to 20Kv) were used. This novel technology requires a high degree of customization for each sample type. In our opinion fixation in glutaraldehyde with OsO4 post-fixation is recommended to preserve finest details, moreover residual liquid elimination is important to increase resolution and avoid beam interference as linear markings. Setting of a proper accelerating voltage allows to correctly visualize the surface topography. Processing CAVs with IL with respect to conventional FE-SEM is useful for several reasons. Mainly this method is time saving (and cost saving), secondary the same sample can be processed for transmission electron microscopy after SEM observations (allowing correlative microscopy), finally EDS can be performed without background noise due to sputter coating. Perhaps now this technique can not completely replaces the conventional SEM in terms of resolution but in our opinion rapid technical improvement can further reduce this gap

Degeneration and regeneration of peripheral nerves: role of thrombin and its receptor PAR-1

The peripheral nervous system has a striking regeneration potential and after damage extensive changes in the differentiation state both of the injured neurons and of the Schwann cells are observed. Schwann cells, in particular, undergo a large scale change in gene expression becoming able to support axonal regeneration. Nerve injury is generally associated to inflammation and activation of the coagulation cascade. Thrombin acts as a polyfunctional signalling molecule exerting its physiological function through soluble target proteins and G-protein-coupled receptors, the protease-activated receptors (PARs) [1]. Recently, we have demonstrated that the activation of the main thrombin receptor, PAR-1, in Schwann cells favours their regenerative potential determining the release of factors which promote axonal regrowth [2]. The pro-regenerative potential of thrombin seems to be exerted in a narrow range of concentrations (pM-nM range). In fact, our preliminary data indicate that high levels of thrombin in the micromolar range slow down Schwann cell proliferation and induce cell death. On the contrary, PAR-1 activating peptides mimic the pro-survival but not the pro-apoptotic effects of thrombin. Controlling thrombin concentration may preserve neuronal health during nerve injury and represent a novel target for pharmacologic therapies