Controlling the specific enrichment of multi-phosphorylated peptides on oxide materials: aluminium foil as a target plate for laser desorption ionization mass spectrometry

A specific multi-phosphopeptide enrichment method is presented to complement current phosphopeptide isolation strategies that normally bias mass spectrometry analysis towards the detection of mono-phosphopeptides. An adsorption model is developed that shows how the physical parameters of adsorption such as specific surface area, adsorption time, etc. control the extraction of mono- and multi-phosphorylated peptides on oxide materials such as alumina. Commercial alumina particles, alumina supported on aluminium particles and alumina on aluminium foils were used to enrich multi-phosphopeptides. The synthesized phosphopeptides and tryptic digests of casein and milk were employed as samples to validate the adsorption simulation. Both experimental and theoretical results show how the selective enrichment of multi-phosphopeptides can be achieved when using extractors with a high specific affinity for phosphate groups but with a relatively small loading capacity or specific surface area. We also show that a commercial aluminium foil represents an ideal substrate to enrich multi-phosphorylated peptides for laser desorption ionisation mass spectrometry

Artificial Photosynthesis at Soft Interfaces

The concept of artificial photosynthesis at a polarised liquid membrane is presented. It includes two photosystems, one at each interface for the hydrogen and oxygen evolution respectively. Both reactions involve proton coupled electron transfer reactions, and some ultrafast steps at the photosensitization stage

Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

EDUCACIÓN AMBIENTAL Y SOCIEDAD. SABERES LOCALES PARA EL DESARROLLO Y LA SUSTENTABILIDAD

Este texto contribuye al análisis científico de varias áreas del conocimiento como la filosofía social, la patología, la educación para el cuidado del medio ambiente y la sustentabilidad que inciden en diversas unidades de aprendizaje de la Licenciatura en Educación para la Salud y de la Maestría en Sociología de la SaludLas comunidades indígenas de la sierra norte de Oaxaca México, habitan un territorio extenso de biodiversidad. Sin que sea una área protegida y sustentable, la propia naturaleza de la región ofrece a sus visitantes la riqueza de la vegetación caracterizada por sus especies endémicas que componen un paisaje de suma belleza

Interactions and Reactivity at Liquid-Liquid Interfaces:A Bio-Inspired System

The interface between two immiscible electrolyte solutions (ITIES) provides a well-defined platform for fundamental studies of adsorption processes and molecular reactivity in general. Two bio-inspired systems are considered in the present work: adsorbed phospholipid monolayers at the classical water-1,2-dichloroethane interface and photosensitized reduction of carbon dioxide at the novel water-supercritical CO2 interface. In first instance, theoretical modeling of adsorption processes at an ideally polarizable ITIES was carried out. In this part of the work, extension of previous models was performed in order to account for the ionic partition of the surface-active molecule. For the sake of simplicity, only a potential-dependent Langmuir isotherm was considered. A general model was then obtained in which prediction of triangular-shaped adsorptive peaks in voltammetric measurements arises naturally. Additionally, the interplay between the Gibbs energies of adsorption and ion-transfer was shown to be especially important for intermediate values between -20 to -40 kJ·mol-1. Adsorbed phospholipid monolayers at the ITIES were employed as a model for mimicking half of a cell membrane. Interactions between peptides and L-α-dipalmitoylphosphatidylcholine (DPPC), the most abundant phospholipid in cell membranes, were proven to occur by voltammetry. Further confirmation of the existence of non-covalent complexes was obtained by the complementary use of biphasic electrospray ionization mass spectrometry (BESI-MS); a technique recently developed in the Laboratoire d'Electrochimie Physique et Analytique (LEPA). Cationization of neutral peptides was equally observed to induce the complex formation with DPPC observed as a net current across the ITIES. Antimicrobial peptides were also considered given their high affinity to cell membranes. Therefore, melittin, selected as model antimicrobial peptide, exhibited a well-defined ion-transfer process accompanied by adsorptive signals. Contact angle estimation of supported interfaces over a platinum electrode indicated that these signals are reversible and induce deformation of deposited aqueous droplets. Earlier desorption of phospholipids was equally observed in presence of the antimicrobial peptide, confirming its membrane-disrupting ability by cyclic voltammetry. Finally, reduction of carbon dioxide was studied at the water-supercritical interface, in an attempt to mimic natural photosynthetic systems. As a first approach, the reduction of CO2 to formate was obtained in presence of decamethylferrocene, an organometallic compound which is capable of reducing protons under anaerobic conditions in 1,2-dichloroethane. However, the reaction follows a different pathway in presence of supercritical CO2 and formate is detected as the most abundant product. Taking one step further the application of water-supercritical CO2 interfaces, the photosensitized reduction of CO2 was conducted. In this approach, nickel(II)-1,4,8,11-tetraazacyclotetradecane (Ni(II)cyclam) was employed as catalyst, ruthenium(II)tris(2,2'-bipyridyl) ([Ru(bpy)3]2+) as photosensitizer and sodium ascorbate as sacrificial electron donor. All the components of the catalytic cycle are dissolved in water. Hence, the presence of supercritical CO2 provides with adsorption sites in which intermediates are hypothesized to be adsorbed, leading to increased efficiency and selectivity simultaneously. Adsorption of the catalyst was observed at the air-water interface and further corroborated by pendant drop shape analysis at the water-supercritical CO2 interface. In what is considered as a very promising approach, modification of the supercritical phase with co-solvents opens the route for the study of many different systems in presence of large amounts of CO2 with the long-term goal of conceiving an efficient artificial leave

Psicología en contexto: retos y desafíos para los investigadores

La investigación ha ocupado un lugar central en la Facultad de Psicología de la Universidad de San Buenaventura Cali. Desde su creación hasta la fecha, la Facultad ha asumido una perspectiva crítica de la disciplina, con la intención explícita de promover un ejercicio profesional reflexivo y ajustado a las necesidades y características de nuestro contexto colombiano. Se trata, por supuesto, de una tarea interminable que solo puede llevarse a cabo por los senderos del diálogo y la discusión. El Primer Encuentro Regional de Psicología se gestó con ese fin y este volumen condensa las ponencias presentadas en dicho encuentro, el 20 de septiembre del 2012. Los trabajos incluyen avances y resultados de investigación, así como ponencias de reflexión teórica. El evento contó con la participación de estudiantes y docentes, así como de algunas ONG de la región. También nos acompañaron como invitados internacionales, la profesora Amelia Haydée Imbriano (Argentina) y el profesor Jorge Juan Román (Cuba).Universidad de San buenaventura - Cal