Proteomic analysis of the ventral disc of Giardia lamblia

<p>Abstract</p> <p>Background</p> <p><it>Giardia lamblia </it>is a multiflagellated protozoan that inhabits the small intestine of vertebrates, causing giardiasis. To colonize the small intestine, the trophozoites form of the parasite remains attached to intestinal epithelial cells by means of cytoskeletal elements that form a structure known as the ventral disc. Previous studies have shown that the ventral disc is made of tubulin and giardins.</p> <p>Results</p> <p>To obtain further information on the composition of the ventral disc, we developed a new protocol and evaluated the purity of the isolation by transmission electron microscopy. Using 1D- and 2D-PAGE and mass spectrometry, we identified proteins with functions associated with the disc. In addition to finding tubulin and giardin, proteins known to be associated with the ventral disc, we also identified proteins annotated in the <it>Giardia </it>genome, but whose function was previously unknown.</p> <p>Conclusions</p> <p>The isolation of the ventral disc shown in this work, compared to previously published protocols, proved to be more efficient. Proteomic analysis showed the presence of several proteins whose further characterization may help in the elucidation of the mechanisms involved in the attachment of the protozoan to epithelial cells.</p

Heterogeneity in the sensitivity of microtubules of Giardia lamblia to the herbicide oryzalin

8 p. : il.Giardia lamblia is a protozoan that inhabits the small intestine of vertebrates, attaching to the epithelial cells by means of cytoskeletal elements. G. lamblia trophozoites possess several microtubular structures, namely the adhesive disc, the median body, the funis and the four pairs of flagella. Several drugs that target cytoskeletal proteins have been used in the study of cytoskeletal function and dynamics. In this work, we used oryzalin, which binds to α-tubulin, as a tool to study the Giardia cytoskeleton. The trophozoites were treated with oryzalin, and its effects were analysed by immunofluorescency, transmission and scanning electron microscopies. Oryzalin inhibited Giardia proliferation. Treated cells were not able to complete cell division and had flagella showing extensive shortening. Strikingly, the drug did not interfere with the adhesive disc, in contrast to what happens when other drugs are used

O uso do método Estudo de Caso na Ciência da Informação no Brasil

This paper shows and reflects about origins, definitions and characteristics of Case Study method. It observes limits of Case Study as survey method. It shows applicability in Information Science scientific researches in Brazil, analyzing thirteen journals recommended by ANCIB . It demonstrates a research application in five papers published among years of 2007 and 2011. It concludes which Case Study if applied correctly can contributes as a research method and  help to enhance researches in Information Science in BrazilO presente artigo apresenta e reflete sobre a origem, definições e características do método Estudo de Caso. Observa os limites do Estudo de Caso como método de pesquisa. Apresenta sua aplicabilidade em pesquisas científicas da área da Ciência da Informação no Brasil, com a análise de treze periódicos recomendados pela ANCIB. Demonstra a aplicação do método em cinco artigos publicados no período de 2007 a 2011. Conclui que o Estudo de Caso se aplicado corretamente pode contribuir como método e ajudar a ampliar as pesquisas em Ciência da Informação no Brasil

The use of case study method in Information Science in Brazil

O presente artigo apresenta e reflete sobre a origem, definições e características do método Estudo de Caso. Observa os limites do Estudo de Caso como método de pesquisa. Apresenta sua aplicabilidade em pesquisas científicas da área da Ciência da Informação no Brasil, com a análise de treze periódicos recomendados pela ANCIB. Demonstra a aplicação do método em cinco artigos publicados no período de 2007 a 2011. Conclui que o Estudo de Caso se aplicado corretamente pode contribuir como método e ajudar a ampliar as pesquisas em Ciência da Informação no Brasil.This paper shows and reflects about origins, definitions and characteristics of Case Study method. It observes limits of Case Study as survey method. It shows applicability in Information Science scientific researches in Brazil, analyzing thirteen journals recommended by ANCIB . It demonstrates a research application in five papers published among years of 2007 and 2011. It concludes which Case Study if applied correctly can contributes as a research method and  help to enhance researches in Information Science in Brazi

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

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

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