7 research outputs found

    A importância do modelo de monocamada lipídica da membrana plasmática de archaea para o ensino de biologia celular no brasil

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    In Biology, a cell is a functional unit of living organisms. Its constituents are mainly genetic material, cytoplasm, and the cell membrane. These three structural components play, among other biological roles, cell reproduction and maintenance, support of a metabolic activity, and maintenance of the physical-chemical barrier. Therefore, to understand a cell structure and its physiology is imperative to study the processes in which these components are involved. In Brazilian higher education, these topics are mainly addressed in Cellular and Molecular Biology subjects, but most of the contents focused on studying the structure, composition, and evolution of the plasma membrane, often referred to generically as the cell membrane. In some clades in Archaea, one of the three domains of life, the cell membrane promotes unique physiological characteristics that confer the evolutionary success of these groups and their survival in environments inhospitable to other lifeways. In these cells, the plasma membranes differ structurally from the membranes of the Bacteria and Eukarya domains which are organized in monolayers, presenting variations in carbon aliphatic chains size, carbon-carbon bonds, and have exclusive structural components such as Glycerol-dialkyl-glycerol-tetraethers (GDGT’s) and Arqueols. Unfortunately, little importance usually occurs to the Archaea domain in the chairs offered to Biological Sciences students. The objective of this work was to compile information about the Archaea membrane and enrich the current literary repertoire used to teach the modules related to the plasma membrane in the disciplines of Cellular and Molecular Biology in Brazil.En Biología, la célula se considera la unidad funcional de los seres vivos. Sus componentes son fundamentalmente: material genético, citoplasma y membrana plasmática. Estos tres componentes estructurales desempeñan, entre otras funciones biológicas, la reproducción y el mantenimiento celular, el soporte de la actividad metabólica y el mantenimiento de la barrera fisicoquímica. Por tanto, para comprender la fisiología y estructura celular, es imperativo estudiar los procesos en los que están involucrados estos componentes. En el ámbito de la educación superior brasileña, estos temas se tratan principalmente en las disciplinas de Biología Celular y Molecular. Gran parte del contenido de dicha disciplina se dedica al estudio de la estructura, composición y evolución de la membrana plasmática, a menudo denominada de forma genérica como membrana celular. En algunos clados de Archaea, uno de los tres dominios de la vida, la membrana celular promueve características fisiológicas únicas que permiten el éxito evolutivo de dichos grupos y su supervivencia en ambientes inhóspitos para otras formas de vida. En estas células, las membranas plasmáticas se diferencian estructuralmente de las membranas de los dominios Bacteria y Eukaria porque están organizadas en una monocapa, presentan variaciones en el tamaño de las cadenas de carbono alifáticas, en los enlaces carbono-carbono y tienen componentes estructurales únicos, tales como tetraéteres de glicerol-dialquil-glicerol (GDGT) y arqueoles. Desafortunadamente, se le da poca importancia al dominio de Archaea en los cursos que se ofrecen a los estudiantes de Ciencias Biológicas. El objetivo de este trabajo fue recopilar información sobre la membrana de Archaea y complementar el repertorio literario actual utilizado para la enseñanza de módulos relacionados con la membrana plasmática en las disciplinas de Biología Celular y Molecular en Brasil.Em Biologia, a célula é considerada a unidade funcional dos seres vivos. Seus constituintes são fundamentalmente material genético, citoplasma e membrana plasmática. Estes três componentes estruturais exercem, dentre outros papéis biológicos, reprodução e manutenção celular, suporte à atividade metabólica e manutenção da barreira físico-química. Portanto, para a compreensão da fisiologia e estrutura celular, é imperativo o estudo dos processos em que esses componentes estão envolvidos, que nos cursos de ensino superior são abordados principalmente nas disciplinas de Biologia Celular e Molecular. Grande parte do conteúdo dessas disciplinas é dedicada ao estudo da estrutura, composição e evolução da membrana plasmática, muitas vezes referida de forma genérica como membrana celular. Em alguns clados em Archaea, um dos três domínios da vida, a membrana celular promove características fisiológicas únicas que permitem o sucesso evolutivo de tais grupos e sua sobrevivência em ambientes inóspitos para outras formas de vida. Nestas células, as membranas plasmáticas diferem estruturalmente das membranas dos domínios Bacteria e Eukaria por se organizarem em monocamada, apresentarem variações no tamanho das cadeias carbônicas alifáticas, nas ligações carbono-carbono e possuírem componentes estruturais exclusivos, como por exemplo os Glicerol-dialkil-glicerol-tetraéteres (GDGTs) e os Arqueóis. Infelizmente, pouca importância é dada ao domínio Archaea nos cursos que são oferecidos a alunos de Ciências Biológicas. O objetivo deste trabalho foi compilar informações sobre a membrana de Archaea e suplementar o atual repertório literário usado para o ensino dos módulos referentes à membrana plasmática nas disciplinas de Biologia Celular e Molecular no Brasil

    On the debate about teleology in biology: the notion of "teleological obstacle"

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    Among the epistemological obstacles described by Gaston Bachelard, we contend that unitary and pragmatic knowledge is correlated to the teleological categories of Ernst Mayr and is the basis for prevailing debate on the notion of "function" in biology. Given the proximity of the aspects highlighted by these authors, we propose to associate the role of teleological thinking in biology and the notion of unitary and pragmatic knowledge as an obstacle to scientific knowledge. Thus, teleological thinking persists acting as an epistemological obstacle in biology, according to Bachelardian terminology. Our investigation led us to formulate the "teleological obstacle," which we consider important for the future of biology and possibly other sciences

    Identificação de concepções antropomórficas, teleológicas e vitalistas entre participantes de uma reunião anual da SBBq

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    The aim of this work was to identify epistemological obstacles amongst participants of XXXIX Annual Meeting of Brazilian Society of Biochemistry and Molecular Biology. A questionnaire with selected excerpts of scientific papers from high impact factor journals was answered by 97 participants of this annual meeting (39 under-graduates, 42 graduate students, and 16 professors and researchers). From Bachelard’s notion of teleological obstacle, it was possible to identify vitalist conceptions (animism), teleological approaches of the evolution processes, expressed in apologies of immanent purposes in organisms’ adaptation, and an anthropomorphic vision of the biological processes under evaluation in the answers and also in the acceptance or not recognition of these obstacles in the excerpts. The presence of figures of speech, metaphors and analogies (verbal obstacle) were verified in explaining the evolution and the immune system, also present in the excerpts.Neste trabalho, buscou-se identificar obstáculos epistemológicos entre os presentes na XXXIX Reunião Anual da Sociedade Brasileira de Bioquímica e Biologia Molecular (SBBq). Um questionário com perguntas e excertos de artigos científicos de revistas de alto fator de impacto foi respondido por 97 presentes (39 estudantes de iniciação científica, 42 pós-graduandos e 16 professores e pesquisadores). A partir da noção de obstáculo epistemológico proposta por Bachelard, foi possível identificar concepções vitalistas (animismo), concepções teleológicas dos processos evolutivos, em afirmações como a existência de objetivos/finalidades na adaptação dos organismos, assim como uma visão antropomórfica dos processos biológicos em avaliação, tanto nas respostas às perguntas como na aceitação ou não identificação destes obstáculos nos excertos. Verificou-se a presença de figuras de linguagem, metáforas e analogias (obstáculo verbal) na explicação da evolução e do sistema imune, também presentes nos excertos dos artigos

    Characterisation of microbial attack on archaeological bone

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    As part of an EU funded project to investigate the factors influencing bone preservation in the archaeological record, more than 250 bones from 41 archaeological sites in five countries spanning four climatic regions were studied for diagenetic alteration. Sites were selected to cover a range of environmental conditions and archaeological contexts. Microscopic and physical (mercury intrusion porosimetry) analyses of these bones revealed that the majority (68%) had suffered microbial attack. Furthermore, significant differences were found between animal and human bone in both the state of preservation and the type of microbial attack present. These differences in preservation might result from differences in early taphonomy of the bones. © 2003 Elsevier Science Ltd. All rights reserved

    Geoeconomic variations in epidemiology, ventilation management, and outcomes in invasively ventilated intensive care unit patients without acute respiratory distress syndrome: a pooled analysis of four observational studies

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    Background: Geoeconomic variations in epidemiology, the practice of ventilation, and outcome in invasively ventilated intensive care unit (ICU) patients without acute respiratory distress syndrome (ARDS) remain unexplored. In this analysis we aim to address these gaps using individual patient data of four large observational studies. Methods: In this pooled analysis we harmonised individual patient data from the ERICC, LUNG SAFE, PRoVENT, and PRoVENT-iMiC prospective observational studies, which were conducted from June, 2011, to December, 2018, in 534 ICUs in 54 countries. We used the 2016 World Bank classification to define two geoeconomic regions: middle-income countries (MICs) and high-income countries (HICs). ARDS was defined according to the Berlin criteria. Descriptive statistics were used to compare patients in MICs versus HICs. The primary outcome was the use of low tidal volume ventilation (LTVV) for the first 3 days of mechanical ventilation. Secondary outcomes were key ventilation parameters (tidal volume size, positive end-expiratory pressure, fraction of inspired oxygen, peak pressure, plateau pressure, driving pressure, and respiratory rate), patient characteristics, the risk for and actual development of acute respiratory distress syndrome after the first day of ventilation, duration of ventilation, ICU length of stay, and ICU mortality. Findings: Of the 7608 patients included in the original studies, this analysis included 3852 patients without ARDS, of whom 2345 were from MICs and 1507 were from HICs. Patients in MICs were younger, shorter and with a slightly lower body-mass index, more often had diabetes and active cancer, but less often chronic obstructive pulmonary disease and heart failure than patients from HICs. Sequential organ failure assessment scores were similar in MICs and HICs. Use of LTVV in MICs and HICs was comparable (42·4% vs 44·2%; absolute difference -1·69 [-9·58 to 6·11] p=0·67; data available in 3174 [82%] of 3852 patients). The median applied positive end expiratory pressure was lower in MICs than in HICs (5 [IQR 5-8] vs 6 [5-8] cm H2O; p=0·0011). ICU mortality was higher in MICs than in HICs (30·5% vs 19·9%; p=0·0004; adjusted effect 16·41% [95% CI 9·52-23·52]; p<0·0001) and was inversely associated with gross domestic product (adjusted odds ratio for a US$10 000 increase per capita 0·80 [95% CI 0·75-0·86]; p<0·0001). Interpretation: Despite similar disease severity and ventilation management, ICU mortality in patients without ARDS is higher in MICs than in HICs, with a strong association with country-level economic status

    The Changing Landscape for Stroke Prevention in AF

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