RESUMO
The organisms inhabiting the deep-seafloor are known to play a crucial role in global biogeochemical cycles. Chemolithoautotrophic prokaryotes, which produce biomass from single carbon molecules, constitute the primary source of nutrition for the higher organisms, being critical for the sustainability of food webs and overall life in the deep-sea hydrothermal ecosystems. The present study investigates the metabolic profiles of chemolithoautotrophs inhabiting the sediments of Menez Gwen and Rainbow deep-sea vent fields, in the Mid-Atlantic Ridge. Differences in the microbial community structure might be reflecting the distinct depth, geology, and distance from vent of the studied sediments. A metagenomic sequencing approach was conducted to characterize the microbiome of the deep-sea hydrothermal sediments and the relevant metabolic pathways used by microbes. Both Menez Gwen and Rainbow metagenomes contained a significant number of genes involved in carbon fixation, revealing the largely autotrophic communities thriving in both sites. Carbon fixation at Menez Gwen site was predicted to occur mainly via the reductive tricarboxylic acid cycle, likely reflecting the dominance of sulfur-oxidizing Epsilonproteobacteria at this site, while different autotrophic pathways were identified at Rainbow site, in particular the Calvin-Benson-Bassham cycle. Chemolithotrophy appeared to be primarily driven by the oxidation of reduced sulfur compounds, whether through the SOX-dependent pathway at Menez Gwen site or through reverse sulfate reduction at Rainbow site. Other energy-yielding processes, such as methane, nitrite, or ammonia oxidation, were also detected but presumably contributing less to chemolithoautotrophy. This work furthers our knowledge of the microbial ecology of deep-sea hydrothermal sediments and represents an important repository of novel genes with potential biotechnological interest.
Assuntos
Sedimentos Geológicos/microbiologia , Fontes Hidrotermais/microbiologia , Metagenômica , Microbiota/fisiologia , Archaea/classificação , Archaea/genética , Archaea/metabolismo , Processos Autotróficos , Açores , Bactérias/classificação , Bactérias/genética , Bactérias/metabolismo , Biodiversidade , Carbono/metabolismo , Ciclo do Carbono , Crescimento Quimioautotrófico/fisiologia , Ciclo do Ácido Cítrico , Epsilonproteobacteria/metabolismo , Metagenoma/fisiologia , Metano/metabolismo , Nitrogênio/metabolismo , Oxirredução , Fotossíntese , Filogenia , RNA Ribossômico 16S/genética , Água do Mar/microbiologia , Enxofre/metabolismoRESUMO
Menez Gwen, Lucky Strike and Rainbow are the three most visited and well-known deep-sea hydrothermal vent fields in the Azores region, located in the Mid-Atlantic Ridge. Their distinct geological and ecological features allow them to support a diversity of vent communities, which are largely dependent on Bacteria and Archaea capable of anaerobic or microaerophilic metabolism. These communities play important ecological roles through chemoautotrophy, feeding and in establishing symbiotic associations. However, the occurrence and distribution of these microbes remain poorly understood, especially in deep-sea sediments. In this study, we provide for the first time a comparative survey of the sediment-associated microbial communities from these three neighbouring vent fields. Sediment samples collected in the Menez Gwen, Lucky Strike and Rainbow vent fields showed significant differences in trace-metal concentrations and associated microbiomes. The taxonomic profiles of bacterial, archaeal and eukaryotic representatives were assessed by rRNA gene-tag pyrosequencing, identified anaerobic methanogens and microaerobic Epsilonproteobacteria, particularly at the Menez Gwen site, suggesting sediment communities potentially enriched in sub-seafloor microbes rather than from pelagic microbial taxa. Cosmopolitan OTUs were also detected mostly at Lucky Strike and Rainbow sites and affiliated with the bacterial clades JTB255, Sh765B-TzT-29, Rhodospirillaceae and OCS155 marine group and with the archaeal Marine Group I. Some variations in the community composition along the sediment depth were revealed. Elemental contents and hydrothermal influence are suggested as being reflected in the composition of the microbial assemblages in the sediments of the three vent fields. Altogether, these findings represent valuable information for the understanding of the microbial distribution and potential ecological roles in deep-sea hydrothermal fields.
Assuntos
Archaea/classificação , Bactérias/classificação , Eucariotos/classificação , Sedimentos Geológicos/microbiologia , Fontes Hidrotermais/microbiologia , Oceano Atlântico , Açores , Filogenia , RNA Ribossômico 16SRESUMO
The deep-sea hydrothermal vent mussel Bathymodiolus azoricus is a symbiont bearing bivalve that is found in great abundance at the Menez Gwen and Lucky Strike hydrothermal vent sites and in close vicinity of the Azores region near the Mid-Atlantic Ridge (MAR). The physiological relationships that vent mussels have developed with their physical and chemical environments are likely to influence global gene expression profiles providing thus the means to investigate distinct biological markers predicting the origin of Bathymodiolus sp. irrespectively of their geographical localization. Differences found at gene expression levels, and between fluorescence in situ hybridization (FISH) and 16S rRNA amplicon sequencing results provided experimental evidence for the distinction of both Menez Gwen and Lucky Strike vent mussel individuals based on bacterial and vent mussel gene expression signatures and on the constitutive distribution and relative abundance of endosymbiotic bacteria within gill tissues. Our results confirmed the presence of methanotroph endosymbionts in Menez Gwen vent mussels whereas Lucky Strike specimens seem to harbor a different bacterial morphotype when a methane monooxygenase gene specific probe was used. No qualitative differences could be visualized between Menez Gwen and Lucky Strike individuals when tested with a sulfur-oxidizing-related probe. Quantitative PCR (qPCR) studies revealed different gene expression profiles in both Menez Gwen and Lucky Strike mussel gill tissues for the immune genes selected. Genes encoding transcription factors presented noticeably low levels of fold expression whether in Menez Gwen or Lucky Strike animals whereas the genes encoding effector molecules appeared to have higher levels expression in gill tissues from Menez Gwen animals. The peptidoglycan recognition molecule encoding gene, PGRP, presented the highest level of transcriptional activity among the genes analyzed in Menez Gwen mussel gill tissues, seconded by carcinolectin and thus denoting the relevance of immune recognition molecules in early stage of the immune responses onset. Genes regarded as encoding molecules involved in signaling pathways were consistently expressed in both Menez Gwen and Lucky Strike mussel gill tissues. Remarkably, the immunity-related GTPase encoding gene demonstrated, in Lucky Strike samples, the highest level of expression among the signaling molecule encoding genes tested when expressions levels were compared between Menez Gwen and Lucky Strike animals. A differential expression analysis of bacterial genes between Menez Gwen and Lucky Strike mussels indicated a clear expression signature in the latter animal gill tissues. The bacterial community structure ensued from the 16S rRNA sequencing analyses pointed at an unpredicted conservation of endosymbiont bacterial loads between Menez Gwen and Lucky Strike samples. Taken together, our results support the hypothesis that B. azoricus exhibits different transcriptional statuses while living in distinct hydrothermal vent sites may result in distinct gene expressions because of physico-chemical and/or symbiont densities differences.
Assuntos
Bivalves/metabolismo , Bivalves/microbiologia , Ecossistema , Regulação da Expressão Gênica/fisiologia , Fontes Hidrotermais , Microbiota/genética , Simbiose , Animais , Oceano Atlântico , Sequência de Bases , Biologia Computacional , Primers do DNA/genética , Geografia , Brânquias/microbiologia , Hibridização in Situ Fluorescente , Dados de Sequência Molecular , RNA Ribossômico 16S/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de DNA , Especificidade da Espécie , TranscriptomaRESUMO
Deep sea hydrothermal Bathymodiolus azoricus mussels from Portuguese EEZ Menez Gwen hydrothermal field possess the remarkable ability to overcome decompression and survive successfully at atmospheric pressure conditions. We investigated the potential use of antioxidant defense enzymes in mussel B. azoricus as biomarkers of oxidative stress induced by long term acclimatization to atmospheric pressure conditions. Mussels collected at Menez Gwen hydrothermal field were acclimatized for two weeks in three distinct conditions suitable of promoting physiological stress, (i) in plain seawater for concomitant endosymbiont bacteria loss, (ii) in plain seawater under metal iron exposure, (iii) constant bubbling methane and pumped sulfide for endosymbiont bacteria survival. The enzymatic activities of superoxide dismutase (SOD), catalase (CAT), and iron storage proteins in addition to electrophoretic profiles were examined in vent mussel gills and digestive gland. Gills showed approximately 3 times more SOD specific activity than digestive glands. On the other hand, digestive glands showed approximately 6 times more CAT specific activity than gills. Iron storage proteins were identified in gill extracts from all experimental conditions mussels. However, in digestive gland extracts only fresh collected mussels and after 2 weeks in FeSO4 showed the presence of iron storage proteins. The differences between SOD, CAT specific activities and the presence of iron storage proteins in the examined tissues reflect dissimilar metabolic and antioxidant activities, as a result of tissue specificities and acclimatization conditions influences on the organism.
Assuntos
Antioxidantes/metabolismo , Pressão Atmosférica , Mytilidae/fisiologia , Água do Mar/microbiologia , Estresse Fisiológico , Animais , Açores , Fenômenos Fisiológicos Bacterianos , Fontes Hidrotermais , Metano/metabolismo , Mytilidae/enzimologia , Mytilidae/microbiologia , Oxirredutases/metabolismo , Água do Mar/química , Sulfetos/metabolismo , SimbioseRESUMO
A presente pesquisa teve por objetivo analisar as representações sociais sobre inclusão de jovens com deficiência intelectual (DI) no segmento de ensino médio (EM), na perspectiva de Jovens Nativos na Pedagogia de Orientação Inclusiva (JNPOI), matriculados numa escola pública de ensino médio de Planaltina, Brasília-DF. Trata-se de uma pesquisa qualitativa, descritivo-interpretativa. Os dados foram obtidos a partir da aplicação do questionário de Livre Associação de Palavras a 186 jovens, dentre os quais, sete tinham DI. Realizamos a análise prototípica desses dados com ajuda do software Iramuteq. Os resultados sugerem que subjacente a uma representação social plenamente favorável à inclusão de pessoas com DI, no segmento de EM, está a busca por afirmar uma identidade compatível com normas, princípios constitucionais e procedimentos jurídicos que condenam firmemente a expressão do preconceito e das atitudes discriminatórias.
En la presente investigación se tuvo por objetivo analizar las representaciones sociales sobre inclusión de jóvenes con deficiencia intelectual (DI) en el segmento de enseñanza secundaria (EM), en la perspectiva de Jóvenes Nativos en la Pedagogía de Orientación Inclusiva (JNPOI), ingresados en una escuela pública de enseñanza secundaria de Planaltina, Brasília-DF. Se trata de una investigación cualitativa, descriptivo-interpretativa. Se obtuvo los datos a partir de la aplicación del cuestionario de Libre Asociación de Palabras a 186 jóvenes, entre los cuales, siete tenían DI. Realizamos el análisis prototípico de esos datos con ayuda del software Iramuteq. Los resultados sugieren que subyacente a una representación social plenamente favorable a la inclusión de personas con DI, en el segmento de EM, está la búsqueda por afirmar una identidad compatible con normas, principios constitucionales y procedimientos jurídicos que condenan firmemente la expresión del preconcepto y de las actitudes discriminatorias.
This research aimed to analyze social representations on the inclusion of young people with intellectual disabilities (ID) in the high school (HS) segment, from the perspective of Young Natives in Inclusion-Oriented Pedagogy (YNIOP) attending a public high school in Planaltina, Brasília-DF. It is a qualitative, descriptive-interpretative research. Data were obtained from the application of the Free Word Association Questionnaire to 186 young students, among which seven had ID. We prototyped this data with the help of the Iramuteq software. The results suggest that, underlying a social representation that is fully favorable to the inclusion of people with ID in the HS segment, there is the search for the affirmation of an identity compatible with norms, constitutional principles and legal procedures that strongly condemn expressions of prejudice and discriminatory attitudes.
Assuntos
Inclusão Escolar , Ensino Fundamental e Médio , Deficiência IntelectualRESUMO
Deep-sea hydrothermal sediments are known to support remarkably diverse microbial consortia. Cultureindependent sequence-based technologies have extensively been used to disclose the associated microbial diversity as most of the microorganisms inhabiting these ecosystems remain uncultured. Here we provide the first description of the microbial community diversity found on sediments from Menez Gwen vent system. We compared hydrothermally influenced sediments, retrieved from an active vent chimney at 812 m depth, with non-hydrothermally influenced sediments, from a 1400 m depth bathyal plain. Considering the enriched methane and sulfur composition of Menez Gwen vent fluids, and the sediment physicochemical properties in each sampled area, we hypothesized that the site-associated microbes would be different. To address this question, taxonomic profiles of bacterial, archaeal and micro-eukaryotic representatives were studied by rRNA gene tag pyrosequencing. Communities were shown to be significantly different and segregated by sediment geographical area. Specific mesophilic, thermophilic and hyperthermophilic archaeal (e.g., Archaeoglobus, ANME-1) and bacterial (e.g., Caldithrix, Thermodesulfobacteria) taxa were highly abundant near the vent chimney. In contrast, bathyal-associated members affiliated to more ubiquitous phylogroups from deep-ocean sediments (e.g., Thaumarchaeota MGI, Gamma- and Alphaproteobacteria). This study provides a broader picture of the biological diversity and microbial biogeography, and represents a preliminary approach to the microbial ecology associated with the deep-sea sediments from the Menez Gwen hydrothermal vent field.
Assuntos
Archaea/genética , Bactérias/genética , DNA/genética , Eucariotos/genética , Sedimentos Geológicos/microbiologia , Fontes Hidrotermais/microbiologia , Archaea/classificação , Oceano Atlântico , Bactérias/classificação , DNA/classificação , Eucariotos/classificação , RNA/genética , RNA Ribossômico/genéticaRESUMO
A presente pesquisa teve como objetivo investigar as representações sociais dosprofessores de ensino médio das escolas públicas de Brasília sobre a inclusão de alunos com deficiência intelectual (DI) e relacioná-la à formação desses professores. Trata-se de umapesquisa qualitativa, descritivo-interpretativa. Os dados foram obtidos a partir da aplicação do questionário de associação livre de palavras a 115 professores de 11 escolas públicas eprocedemos à análise prototípica desses dados com auxílio do software Evoc. Essa análise foi realizada inicialmente com todos os 115 professores e, posteriormente, apenas com aqueles que declararam ter formação em educação inclusiva. Concluímos que as representações sociais de professores estão objetivadas no binômio legítimo, porém, difícil. Assim, o aluno com DI érepresentado como especial, porém, imperceptível, discriminado e gera desafio e dificuldade para o professor, que se sente despreparado. Essa representação contrasta com a representação social específica de um subgrupo de professores que apresenta formação continuada em educação inclusiva. Para esse subgrupo, o aluno com DI é constituído de necessidades, mas também de potencialidades. Ele é representado como capaz e dificuldade. Os resultados indicam que a informação advinda do curso de formação é valorizada na representação social, contudo, ela adquire sentido não só em função dos elementos cognitivos, mas também dos elementos afetivos...
This study aimed at investigating the social representations of high school teachers from public schools of Brasilia about the inclusion of students with intellectual disabilities and relate those representations with the training courses of these teachers. Our theoretical framework is based on Social Representations Theory and educational inclusion literature. We applied the free association questionnaire to 115 teachers from 11 public schools and proceed to the analysis of these empirical data using the software Evoc. This analysis was initially performedwith all 115 teachers and later, only with those who had training courses in inclusive education. Results indicated that teachers´ social representations is objectified in the binomial legal, however, difficult. Thus, students with intellectual disabilities are represented as special, however, imperceptible. They represent challenge and difficulty for teachers who feel unprepared and unmotivated to make changes. This representation contrasted, however, with the social representation of a specific subgroup of teachers who had specific training during under graduation in inclusive education. For this subgroup, students with intellectual disabilities consists of needs, but also of possibilities, so they were represented as capable and difficult. Results indicated that information from the courses is important in that social context, however, it made sense not only in terms of the cognitive but also to affective elements...
Assuntos
Humanos , Ensino Fundamental e Médio , Deficiência Intelectual , Inclusão Escolar , Psicologia SocialRESUMO
Este artigo apresenta uma analise das opiniões dos professores e alunos sobre a relação ensino e aprendizagem na modalidade de Educação a Distância de uma Universidade de ensino superior. Esta pesquisa constitui-se em um Estudo de Caso com caráter exploratóriopautada no aporte teórico das representações sociais. Participaram do estudo dezenove professores e noventa alunos do sétimo período do curso de Pedagogia EAD Turma 2006/1. Asestratégias metodológicas empregadas na coleta de dados foram a técnica de associação livre por meio do instrumento de complementação de frases, um questionário com perguntas abertas e fechadas e uma entrevista semiestruturada. Utilizou-se o programa Evoc para a organização dos dados do instrumento de complementação de frases. Os dados foram codificados etabulados de forma quantitativa e qualitativa. Realizou-se adaptação da técnica de análise de conteúdo de Bardin para os dados subjetivos. A partir dos resultados obtidos, constatou-se, que as opiniões de ambos os grupos têm uma estrutura da qual participam elementos positivos e negativos com relação ao objeto de pesquisa investigado. Identificou-se que as opiniões dos professores e alunos participantes desta pesquisa com relação ao ensino e à aprendizagem namodalidade EAD, estão ancoradas ao modelo de ensino tradicional. Evidenciou-se assim, a necessidade de uma desmistificação dos paradigmas sobre a EAD que ainda se encontrampresentes na posição dos alunos e dos professores...
This paper presents an analysis of the views of teachers and students about the relationship between teaching and learning in the form of distance education from a college of higher learning. This research is on a case study with exploratory guided the theoretical framework of social representations. The study included nineteen ninety teachers and studentsof the seventh semester of the Distance Education Pedagogy - Class 2006/1. The methodological strategies used in data collection were the technique of free association through the instrumentcomplementing sentences, a questionnaire with open and closed questions and a semistructured interview. The Evoc program was used to organize the data instrument complementing sentences. Data were coded and tabulated quantitatively and qualitatively. Held adapting the technique of content analysis of Bardin for subjective data. From the results obtained, it was found that the opinions of both groups have a structure which involved positive and negative with respect to the object of research investigated elements. It was found that the opinions of teachers and students participating in this research about teaching and learning in distanceeducation mode, are anchored to the traditional teaching model. It was evident thus the need for demystification of paradigms on the DL that are still present in the position of students and teachers...
Assuntos
Humanos , Educação a Distância , Docentes , Aprendizagem , Psicologia Social , Estudantes , EnsinoRESUMO
O artigo apresenta parte de uma pesquisa de mestrado que utilizou como referencial epistemológico a teoria da criatividade de Winnicott. A investigação aconteceu a partir de entrevistas com professores da 2a Fase do Ensino Fundamental de escolas da rede pública e particular de Brasília-DF, a fim de compreendermos a interpretação dos educadores sobre o processo de constituição do sujeito-aluno no entretecer de comportamentos transgressores e criativos no trabalho-educar. Concluiu-se que a transgressão pode ser considerada parte do processo criativo para o aluno, tanto em relação a ações e produções no mundo social quanto à criação da própria identidade do indivíduo.
The article presents part of the research methodologically oriented by the creativity theory of Winnicott. For subjects we had teachers of second phase of the fundamental level (6th year to 9th year) from two different types of schools: particular and public schools, aiming to understand the relationship between transgression behaviors and creativity of pupils and their subjective constitution. During the research we verified positive and negative aspects about the behavior of the student, we examined if there were relations between creative and transgressor behavior. From the psychoanalysis theory about creativity we conclude that transgression may be part of the creative process of the student, including also social productions and identity constitution.
El artículo presenta parte de una búsqueda de maestría que utilizó como referencia epistemológica a la teoría de la creatividad de Winnicott. La investigación aconteció a partir de entrevistas con profesores de la 2a etapa de la enseñanza primaria de escuelas de la red pública y particular de Brasilia-DF, con el propósito de comprender la interpretación de los educadores sobre el proceso de constitución del sujeto-alumno en el entrelazar de comportamientos transgresores y creativos en el trabajo-educativo. Se concluyó que, la transgresión puede ser considerada parte del proceso creativo para el alumno, tanto en relación a las acciones y producciones en el mundo social cuanto a la creación de la propia identidad de este sujeto.