Redox characteristics of the eukaryotic cytosol

AbstractThe eukaryotic cytoplasm has long been regarded as a cellular compartment in which the reduced state of protein cysteines is largely favored. Under normal conditions, the cytosolic low-molecular weight redox buffer, comprising primarily of glutathione, is highly reducing and reactive oxygen species (ROS) and glutathionylated proteins are maintained at very low levels. In the present review, recent progress in the understanding of the cytosolic thiol–disulfide redox metabolism and novel analytical approaches to studying cytosolic redox properties are discussed. We will focus on the yeast model organism, Saccharomyces cerevisiae, where the combination of genetic and biochemical approaches has brought us furthest in understanding the mechanisms underlying cellular redox regulation. It has been shown in yeast that, in addition to the enzyme glutathione reductase, other mechanisms may exist for restricting the cytosolic glutathione redox potential to a relatively narrow interval. Several mutations in genes involved in cellular redox regulation cause ROS accumulation but only moderate decreases in the cytosolic glutathione reducing power. The redox regulation in the cytosol depends not only on multiple cytosolic factors but also on the redox homeostasis of other compartments like the secretory pathway and the mitochondria. Possibly, the cytosol is not just a reducing compartment surrounding organelles with high oxidative activity but also a milieu for regulation of the redox status of more than one compartment. Although much has been learned about redox homeostasis and oxidative stress response several important aspects of the redox regulation in the yeast cytosol are still unexplained

Tratamento da comunicação científica a partir das Bases Biológicas disciplinares da Medicina

Medical education in Cuba is the ideal setting for the formation of competencies that guarantee the generation and socialization of research results contextualized to current challenges. During the year 2021, a descriptive study with a socio-formative approach was carried out at the University of Medical Sciences of Camagüey, with the purpose of revealing the potentialities of the discipline Biological Bases of Medicine (BBM) for the formation of scientific communication competence. From it, the causes, theoretical and practical deficiencies that have an impact on the formation of this competence from the initial training in the medical student and its impact on educational practice are determined. The potentialities of this discipline and its involvement in the formation of a culture to obtain, elaborate and communicate the results of the research activity as basic elements for scientific socialization were identified. The methodological work of the year group, focused on the potentialities identified from a socio-formative approach, makes it possible to train and develop the competence under study, oriented towards the socialization of the results of the research activity carried out by the student during education at work and extension activities. La enseñanza médica en Cuba constituye el escenario ideal para la formación de las competencias que garantizan la generación y socialización de resultados investigativos contextualizados a los desafíos actuales. Durante el año 2021, se realizó un estudio descriptivo con enfoque socio formativo en la Universidad de Ciencias Médicas de Camagüey, con el propósito de develar las potencialidades de la disciplina Bases Biológicas de la Medicina (BBM) para la formación de la competencia comunicación científica. A partir del mismo se determinan las causas, carencias teóricas y prácticas que repercuten en la formación de dicha competencia desde la formación inicial en el estudiante de Medicina y su incidencia en la práctica educativa. Fueron identificadas las potencialidades de esta disciplina y su implicación en la formación de una cultura para obtener, elaborar y comunicar los resultados de la actividad investigativa como elementos básicos para la socialización científica. El trabajo metodológico del colectivo de año, enfocado en las potencialidades identificadas desde un enfoque socio formativo posibilita formar y desarrollar la competencia objeto de estudio, orientada hacia la socialización de los resultados de la actividad investigativa que realiza el estudiante durante la educación en el trabajo y actividades extensionistas.A educação médica em Cuba é o cenário ideal para a formação de competências que garantam a geração e a socialização dos resultados da pesquisa contextualizados aos desafios atuais. Durante o ano de 2021, foi realizado um estudo descritivo com abordagem socioamotiva na Universidade de Ciências Médicas de Camagüey, com o objetivo de revelar as potencialidades da disciplina Bases Biológicas da Medicina (BBM) para a formação de competência de comunicação científica. A partir dela, são determinadas as causas, deficiências teóricas e práticas que impactam na formação dessa competência a partir da formação inicial do estudante de medicina e seu impacto na prática educacional. Foram identificadas as potencialidades dessa disciplina e seu envolvimento na formação de uma cultura para a obtenção, elaboração e comunicação dos resultados da atividade de pesquisa como elementos básicos para a socialização científica. O grupo metodológico do ano, focado nas potencialidades identificadas a partir de uma abordagem socioamsenária, possibilita a formação e desenvolvimento da competência em estudo, orientada para a socialização dos resultados da atividade de pesquisa realizada pelo aluno durante as atividades de ensino no trabalho e extensão.

Prospects for Cherenkov Telescope Array observations of the young supernova remnant RX J1713.7-3946

We perform simulations for future Cherenkov Telescope Array (CTA) observations of RX J1713.7−3946, a young supernova remnant (SNR) and one of the brightest sources ever discovered in very high energy (VHE) gamma rays. Special attention is paid to exploring possible spatial (anti)correlations of gamma rays with emission at other wavelengths, in particular X-rays and CO/H I emission. We present a series of simulated images of RX J1713.7−3946 for CTA based on a set of observationally motivated models for the gamma-ray emission. In these models, VHE gamma rays produced by high-energy electrons are assumed to trace the nonthermal X-ray emission observed by XMM-Newton, whereas those originating from relativistic protons delineate the local gas distributions. The local atomic and molecular gas distributions are deduced by the NANTEN team from CO and H I observations. Our primary goal is to show how one can distinguish the emission mechanism(s) of the gamma rays (i.e., hadronic versus leptonic, or a mixture of the two) through information provided by their spatial distribution, spectra, and time variation. This work is the first attempt to quantitatively evaluate the capabilities of CTA to achieve various proposed scientific goals by observing this important cosmic particle accelerator

A flat vision methodological approach to evaluate health professional’s competence

Este trabajo parte de la problemática que existe en el proceso de evaluación de la capacidad de dirección de los directivos de la provincia de Granma. La evaluación no es óptima en sus diferentes componentes, porque  las conductas que asumen los evaluadores no se corresponden con el comportamiento real del evaluado; por otra parte el estudio permitió demostrar que en la integración entre los componentes evaluativos no se materializan aspectos esenciales del proceso, enfocado  desde  esta  óptica, no  ha  sido suficientemente estudiado y no se cuenta con orientaciones metodológicas precisas que orienten a los evaluadores la manera de proceder. Como vía de solución se elaboró una metodología para el perfeccionamiento del proceso de evaluación de la capacidad de los directivos. La metodología está basada en los principios de la unidad de  lo  afectivo  y  lo  cognitivo,  del  desarrollo  psicológico  como  resultado  de  la relación dialéctica de los planos interpsicológico e intrapsicolόgico,  de  la  actividad de  dirección,  de la participación democrática de los colaboradores, y la estimulación de la actividad creativa.  Los procedimientos de la metodología por sus características se insertan dentro del funcionamiento normal de la institución. En el proceso investigativo se emplearon los métodos del nivel teórico: tránsito de lo abstracto  a  lo  concreto,  histórico  lógico,   y  analítico  – sintético; del nivel empírico: la observación al proceso de evaluación, criterio de expertos, y auxiliado  por  la  encuesta, la entrevista y el análisis  documental;  en  el  análisis  cuantitativo  se  empleó  la estadística descriptiva. Con el pre experimento se demostró la  efectividad de la metodología.Introduction: the preparedness of a proper human resource to fulfill the social and current demands depends on the adequate evaluation of its professional performance. The evaluation is not optimal in all of its components because the evaluators' behaviors are not in agreement with the evaluated real behaviors.Objective: to design a methodology that allows the improvement of the evaluation of health professionals´ performance.Method: in the research process, theoretical methods were used such as the abstract and concrete, historical and logical, and analytical and synthetical. From the empirical level: the observation, expert criteria, survey, interview, and documentary analysis. In the quantitative analysis it was applied the descriptive statistics.Results: the study demonstrated that in the integration among the evaluative components there are not materialized the essential aspects of the process, according to this perspective, the problem has not been properly studied and there are no specific methodological guidelines to direct the evaluators in their task.Conclusions: as a solution proposal, a methodology was elaborated for the improvement of the evaluation process of the managers' capacity. The methodology was based on principles concerning the unity between affective and cognitive aspects, psychological development as a result of the dialectic relationship between the interpsychological and intrapsychological components involved in the managerial activity, the democratic participation of the collaborators, and the stimulation of the creative activity

Manager or leader in the evaluation of professional competence

La calidad de un servicio de salud depende de la capacidad de los recursos humanos responsabilizados con el mismo. En Granma actualmente no existe un referente teórico que permita evaluar adecuadamente la capacidad de dirección de los directivos, atendiendo a las funciones atencionales, docentes, administrativa e investigativas del personal directivo. El primer momento de la investigación estuvo dirigido al estudio, análisis y al establecimiento de consenso sobre las bases teóricas y metodológicas que fundamentan el diseño del referente. El objetivo está encaminado a la elaboración de un referente teórico de la profesionalidad del directivo de salud que permita integrar cuatro dimensiones (la sociopsicológica, técnica-organizativa, técnica – profesional y dirección de la actividad científica investigativa) y un sistema de conocimientos, un sistema de habilidades y un sistema de valores con el fin de realizar una evaluación del desempeño profesional justa, objetiva, equilibrada y personalizada, no solo a partir de los resultados profesionales y técnicos, sino teniendo en cuenta la integración de las dimensiones, exponiéndole un carácter holístico y exhaustivo. Se utilizaron diferentes métodos de investigación de carácter teórico y empírico,  comprobándose la validez y efectividad de la propuesta a través del método de evaluación por criterio de expertos  y usuarios.Health care quality depends on the capacity of the human resources responsible for it. At present, in Granma province there is not a theoretical referent for an adequate evaluation of managers’ management capacity, concerning their caring, teaching, managerial, and investigative functions. The first stage of this research focused on the analysis and establishment of a consensus in relation to the theoretical and methodological basis that support the design of the referent. The objective of this paper is the elaboration of a theoretical referent of health managers’ professionalism that allows the  integration of four dimensions (sociopsychological, technical and organizational, technical and professional, and scientific and investigative management) and a knowledge system, a skill  system, and a value  system aimed at evaluating professional competence in an objective, balanced, and  personalized way, based not only on professional and technical results, but also on the  integration of the suggested dimensions in a holistic and exhaustive way.Empirical and theoretical research methods such as expert and user criteria were used to verify the validity and effectiveness of the proposal.

Simulations of Accretion Powered Supernovae in the Progenitors of Gamma Ray Bursts

Observational evidence suggests a link between long duration gamma ray bursts (LGRBs) and Type Ic supernovae. Here, we propose a potential mechanism for Type Ic supernovae in LGRB progenitors powered solely by accretion energy. We present spherically-symmetric hydrodynamic simulations of the long-term accretion of a rotating gamma-ray burst progenitor star, a "collapsar," onto the central compact object, which we take to be a black hole. The simulations were carried out with the adaptive mesh refinement code FLASH in one spatial dimension and with rotation, an explicit shear viscosity, and convection in the mixing length theory approximation. Once the accretion flow becomes rotationally supported outside of the black hole, an accretion shock forms and traverses the stellar envelope. Energy is carried from the central geometrically thick accretion disk to the stellar envelope by convection. Energy losses through neutrino emission and nuclear photodisintegration are calculated but do not seem important following the rapid early drop of the accretion rate following circularization. We find that the shock velocity, energy, and unbound mass are sensitive to convective efficiency, effective viscosity, and initial stellar angular momentum. Our simulations show that given the appropriate combinations of stellar and physical parameters, explosions with energies ~5x10^50 ergs, velocities 3000 km/s, and unbound material masses >6 solar masses are possible in a rapidly rotating 16 solar mass main sequence progenitor star. Further work is needed to constrain the values of these parameters, to identify the likely outcomes in more plausible and massive LRGB progenitors, and to explore nucleosynthetic implications.Comment: 20 Pages, 15 Figures, Accepted to Ap

Validación de un método espectrofotométrico para la determinación del contenido de aldehídos en el aceite de girasol ozonizado (OLEOZON®)

El aceite de girasol ozonizado OLEOZON® presenta excelentes propiedades germicidas (bactericida, fungicida virucida y antiparasitario) que permiten su utilización en el tratamiento de enfermedades de origen infeccioso. En este trabajo se presenta la validación del método espectrofotométrico de determinación de los aldehídos presentes en el aceite de girasol ozonizado OLEOZON®, a través de la formación de sus derivados 2,4-dinitrofenilhidrazonas y la posterior medición de la absorbancia a 338 nm. La evaluación del método establecido se realizó mediante la determinación de los parámetros de linealidad, precisión, exactitud, especificidad y sensibilidad. En la evaluación de este método analítico se obtuvieron pruebas suficientes para demostrar que dicho método resulta lineal (r = 0,999 y r2 = 0,998), preciso (repetibilidad CV = 0,38 %, precisión intermedia CV = 0,81 %) exacto (recobrado³ 97,8 %) y sensible (límite de detección = 1,04 · 10-9 mol/L y límite de cuantificación = 1,28 · 10-9 mol/L) en el intervalo de concentraciones de aldehídos estudiado. Los diferentes compuestos presentes en el OLEOZON®, tales como: peróxidos, ácidos carboxílicos, ozónidos, y compuestos poliméricos no interfieren en la determinación del contenido de aldehídos por este método, por lo que es específico. Se realizó la determinación de la concentración de aldehídos referida al nonanal, en una muestra representativa de OLEOZON® que resultó de (1,21 ± 0,04) mmol/g

Participation of Low Molecular Weight Electron Carriers in Oxidative Protein Folding

Oxidative protein folding is mediated by a proteinaceous electron relay system, in which the concerted action of protein disulfide isomerase and Ero1 delivers the electrons from thiol groups to the final acceptor. Oxygen appears to be the final oxidant in aerobic living organisms, although the existence of alternative electron acceptors, e.g. fumarate or nitrate, cannot be excluded. Whilst the protein components of the system are well-known, less attention has been turned to the role of low molecular weight electron carriers in the process. The function of ascorbate, tocopherol and vitamin K has been raised recently. In vitro and in vivo evidence suggests that these redox-active compounds can contribute to the functioning of oxidative folding. This review focuses on the participation of small molecular weight redox compounds in oxidative protein folding

Subcellular distribution of glutathione and its dynamic changes under oxidative stress in the yeast Saccharomyces cerevisiae

Glutathione is an important antioxidant in most prokaryotes and eukaryotes. It detoxifies reactive oxygen species and is also involved in the modulation of gene expression, in redox signaling, and in the regulation of enzymatic activities. In this study, the subcellular distribution of glutathione was studied in Saccharomyces cerevisiae by quantitative immunoelectron microscopy. Highest glutathione contents were detected in mitochondria and subsequently in the cytosol, nuclei, cell walls, and vacuoles. The induction of oxidative stress by hydrogen peroxide (H2O2) led to changes in glutathione-specific labeling. Three cell types were identified. Cell types I and II contained more glutathione than control cells. Cell type II differed from cell type I in showing a decrease in glutathione-specific labeling solely in mitochondria. Cell type III contained much less glutathione contents than the control and showed the strongest decrease in mitochondria, suggesting that high and stable levels of glutathione in mitochondria are important for the protection and survival of the cells during oxidative stress. Additionally, large amounts of glutathione were relocated and stored in vacuoles in cell type III, suggesting the importance of the sequestration of glutathione in vacuoles under oxidative stress