Últimos itens adicionados do Acervo: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia

O Inmetro é uma autarquia federal, vinculada ao Ministério do Desenvolvimento, Indústria e Comércio Exterior, que atua como Secretaria Executiva do Conselho Nacional de Metrologia, Normalização e Qualidade Industrial (Conmetro), colegiado interministerial, que é o órgão normativo do Sistema Nacional de Metrologia, Normalização e Qualidade Industrial (Sinmetro).

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‣ A sustentabilidade e programas de avaliação da conformidade [slides]

Kuster, Gustavo José
Fonte: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia Publicador: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia
Tipo: Trabalho apresentado em evento / Paper
Português
24 slides : il.; Palestra realizada para os funcionarios dos Correios sobre o uso da Avaliação da Conformidade nas compras públicas, destacando a experiència do Inmetro com o FNDE e o programa "A caminho da Escola". Realizada em Brasilia em 28 de fevereiro de 2012.

‣ Inorganic polyphosphate inhibits an aspartic protease-like activity in the eggs of rhodnius prolixus (Stahl) and impairs yolk mobilization in vitro

Gomes, Fabio Mendonça; Santos, Danielle Maria Perpétua de Oliveira; Maia, Lucimar Soares Motta; Ramos, Isabela Barbosa; Miranda, Kildare Rocha de; Machado, Ednildo de Alcântara
Fonte: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia Publicador: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia
Tipo: Artigo de Revista Científica
Português
6 p. : il.; Inorganic polyphosphate (poly P) is a polymer of phosphate residues that has been shown to act as modulator of some vertebrate cathepsins. In the egg yolk granules of Rhodnius prolixus, a cathepsinDis the main protease involved in yolk mobilization and is dependent on an activation by acid phosphatases. In this study, we showed a possible role of poly P stored inside yolk granules on the inhibition of cathepsinDand arrest of yolk mobilization during early embryogenesis of these insects. Enzymatic assays detected poly P stores inside the eggs of R. prolixus. We observed that micromolar poly P concentrations inhibited cathepsin D proteolytic activity using both synthetic peptides and homogenates of egg yolk as substrates. Poly P was a substrate for Rhodnius acid phosphatase and also a strong competitive inhibitor of a pNPPase activity. Fusion events have been suggested as important steps towards acid phosphatase transport to yolk granules. Weobserved that poly P levels in those compartments were reduced after in vitro fusion assays and that the remaining poly P did not have the same cathepsinDinhibition activity after fusion. Our results are consistent with the hypothesis that poly P is a cathepsinDinhibitor and a substrate for acid phosphatase inside yolk granules. It is possible that...

‣ A atuação do Inmetro na regulamentação de produtos [slides]

Rocha, Leonardo Machado
Fonte: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia Publicador: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia
Tipo: Trabalho apresentado em evento / Paper
Português
20 slides : il.; Apresentação ministrada, em 04 de outubro de 2011, no Seminário de Operações de Comércio Exterior, em Brasília, por solicitação do Departamento de Comércio Exterior (Decex) do Ministério do Desenvolvimento, Indústria e Comércio exterior (MDIC), visando o nivelamento de informações junto aos operadores econômicos no comércio exterior, em especial importadores de produtos regulamentados pelo Inmetro, em função do início da atuação do Inmetro no controle das operações de comércio exterior.

‣ Certificação de Produtos [slides]

Rocha, Leonardo Machado
Fonte: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia Publicador: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia
Tipo: Trabalho apresentado em evento / Paper
Português
25 slides : il.; Apresentação ministrada, em 30 de setembro de 2010, no Encontro Nacional Abracopel de Atualização Docente em Segurança com Eletricidade (ENADSE), em São Paulo, visando debater e esclarecer aos professores de Escolas Técnicas e Centros Tecnológicos sobre as atividades do Inmetro, bem como sobre as regulamentações e ações do Inmetro em prol da promoção da segurança elétrica.

‣ Avaliação da Conformidade [slides]

Kuster, Gustavo José
Fonte: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia Publicador: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia
Tipo: Trabalho apresentado em evento / Paper
Português
39 slides : il.; Palestra realizada 13 de setembro de 2011, para os profissionais do INPI com a finalidade de apresentar, de forma mais detalhada, o processo de avaliação da conformidade e analisar a interface desse com o processo de concessão de Marcas e Patentes, no que diz respeito a denominação de origem.

‣ Requisitos Gerais de Certificação (RGCP) [slides]

Kuster, Gustavo José
Fonte: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia Publicador: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia
Tipo: Trabalho apresentado em evento / Paper
Português
7 slides : il.; Palestra realizada em 10 de março de 2011 em São Paulo, na sede da Associação Brasileira de Organismos de Certificação sobre os Requisitos Gerais de Certificação de Produtos, que vieram a mudar a estrutura documental do processo de certificação, simplificando e agilizando o mesmo. Essa palestra foi ministrada na abertura do curso, dado nessa Associação, para capacitação de profissionais na elaboração de RAC.

‣ Macroprocesso implantação assistida de programas de avaliação da conformidade [slides]

Rocha, Leonardo Machado
Fonte: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia Publicador: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia
Tipo: Trabalho apresentado em evento / Paper
Português
41 slides : il.; Apresentação ministrada, em 18 de abril de 2012, no Curso sobre os Requisitos Gerais de Certificação de Produtos (RGCP), na Federação das Indústrias do Estado de São Paulo (FIESP), com o objetivo de capacitar o setor produtivo para a elaboração de minutas de Requisitos de Avaliação da Conformidade (RAC), visando aumentar a capacidade do Inmetro no desenvolvimento de Programas de Avaliação da Conformidade.

‣ Calcium- and polyphosphate containing acido calcisomes in chicken egg yolk

Ramos, Isabela Barbosa; Miranda, Kildare Rocha de; Ulrich, Paul; Ingram, Peter; LeFurgey, Ann; Machado, Ednildo de Alcântara; Souza, Wanderley de; Docampo, Roberto
Fonte: Multimedia Publicador: Multimedia
Tipo: Artigo de Revista Científica
Português
14 p. : il., tab; Background information. Poly P (inorganic polyphosphate) is a polymer formed by Pi residues linked by high-energy phosphoanhydride bonds. The presence of poly P in bacteria, fungi, algae and protists has been widely recognized, but the distribution of poly P in more complex eukaryotes has been poorly studied. Poly P accumulates, together with calcium, in acidic vesicles or acidocalcisomes in a number of organisms and possesses a diverse array of functions, including roles in stress response, blood clotting, inflammation, calcification, cell proliferation and apoptosis. Results. We report here that a considerable amount of phosphorus in the yolk of chicken eggs is in the form of poly P. DAPI (4 ,6-diamidino-2-phenylindole) staining showed that poly P is localized mainly in electron-dense vesicles located inside larger vacuoles (compound organelles) that are randomly distributed in the yolk. These internal vesicles were shown to contain calcium, potassium, sodium, magnesium, phosphorus, chlorine, iron and zinc, as detected by X-ray microanalysis and elemental mapping. These vesicles stain with the acidophilic dye Acridine Orange. The presence of poly P in organellar fractions of the egg yolk was evident in agarose gels stained with Toluidine Blue and DAPI. Of the total phosphate (Pi) of yolk organelles...

‣ Transcriptome and gene expression profile of ovarian follicle tissue of the triatomine bug Rhodnius prolixus

Medeiros, Marcelo Neves de; Oliveira, Raquel Lima Logullo de; Ramos, Isabela Barbosa; Sorgine, Marcos Henrique Ferreira; Silva, Gabriela de Oliveira Paiva e; Mesquita, Rafael Dias; Machado, Ednildo de Alcântara; Coutinho, Maria Alice de Almeida; Masuda,
Fonte: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia Publicador: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia
Tipo: Artigo de Revista Científica
Português
9 p. : il.; Insect oocytes grow in close association with the ovarian follicular epithelium (OFE), which escorts the oocyte during oogenesis and is responsible for synthesis and secretion of the eggshell. We describe a transcriptome of OFE of the triatomine bug Rhodnius prolixus, a vector of Chagas disease, to increase our knowledge of the role of FE in egg development. Random clones were sequenced from a cDNA library of different stages of follicle development. The transcriptome showed high commitment to transcription, protein synthesis, and secretion. The most abundant cDNA was a secreted (S) small, proline-rich protein with maximal expression in the vitellogenic follicle, suggesting a role in oocyte maturation. We also found Rp45, a chorion protein already described, and a putative chitin-associated cuticle protein that was an eggshell component candidate. Six transcripts coding for proteins related to the unfolded-protein response (UPR) by were chosen and their expression analyzed. Surprisingly, transcripts related to UPR showed higher expression during early stages of development and downregulation during late stages, when transcripts coding for S proteins participating in chorion formation were highly expressed. Several transcripts with potential roles in oogenesis and embryo development are also discussed. We propose that intense protein synthesis at the FE results in reticulum stress (RS) and that lowering expression of a set of genes related to cell survival should lead to degeneration of follicular cells at oocyte maturation. This paradoxical suppression of UPR suggests that ovarian follicles may represent an interesting model for studying control of RS and cell survival in professional S cell types.

‣ Microscopic and molecular characterization of ovarian follicle atresia in rhodnius prolixus stahl under immune challenge

Medeiros, Marcelo Neves de; Ramos, Isabela Barbosa; Santos, Danielle Maria Perpétua de Oliveira; Silva, Rodrigo Caetano Belmonte da; Gomes, Fabio Mendonça; Medeiros, Luciano Neves de; Kurtenbach, Eleonora; Chiarini, Luciana Barreto; Masuda, Hatisaburo;
Fonte: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia Publicador: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia
Tipo: Artigo de Revista Científica
Português
9 p. : il.; In this work we characterized the degenerative process of ovarian follicles of the bug Rhodnius prolixus challenged with the non-entomopathogenic fungus Aspergillus niger. An injection of A. niger conidia directly into the hemocoel of adult R. prolixus females at the onset of vitellogenesis caused no effect on host lifespan but elicited a net reduction in egg batch size. Direct inspection of ovaries from the mycosed insects revealed that fungal challenge led to atresia of the vitellogenic follicles. Light microscopy and DAPI staining showed follicle shrinkage, ooplasm alteration and disorganization of the monolayer of follicle cells in the atretic follicles. Transmission electron microscopy of thin sections of follicle epithelium also showed nuclei with condensed chromatin, electron dense mitochondria and large autophagic vacuoles. Occurrence of apoptosis of follicle cells in these follicles was visualized by TUNEL labeling. Resorption of the yolk involved an increase in protease activities (aspartyl and cysteinyl proteases) which were associated with precocious acidification of yolk granules and degradation of yolk protein content. The role of follicle atresia in nonspecific host–pathogen associations and the origin of protease activity that led to yolk resorption are discussed.

‣ Calreticulin expression levels and endoplasmic reticulum during late oogenesis and early embryogenesis of rhodnius prolixus stahl

Ramos, Isabela Barbosa; Campos, Claudia Barbosa Ladeira de; Sorgine, Marcos Henrique Ferreira; Souza, Wanderley de; Machado, Ednildo de Alcântara
Fonte: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia Publicador: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia
Tipo: Artigo de Revista Científica
Português
11 p. : il.; This study reports the cloning, expression analysis and localization of calreticulin (CRT) in the endoplasmic reticulum (ER) during late oogenesis and early embryogenesis of the insect Rhodnius prolixus. CRT was cloned and sequenced from cDNA extracted from unfertilized eggs. Real-time PCR showed that CRT expression remains at lower levels during late oogenesis when compared to vitellogenic oocytes or day 0 laid fertilized eggs. Immunofluorescence microscopy showed that this protein is located in the periphery of the egg, in a differential peripheral ooplasm surrounding the yolk-rich internal ooplasm, only identified by transmission electron microscopy (TEM) of thin sections. Using immunogold electron microscopy, the ER ultrastructure (CRT labeled) was identified in the peripheral ooplasm as dispersed lamellae, randomly distributed in the peripheral ooplasm. No massive alterations of ER ultrastructure were found before or right after (30 min) fertilization, but an increase in CRT expression levels and assembly of typical rough ER (parallel cisternae with associated ribosomes) were observed 18–24 h after oviposition. The lack of ER assembly at fertilization and the later formation of rough ER together with the increase in CRT expression levels...

‣ Acidocalcisomes as calcium- and polyphosphate-storage compartments during embryogenesis of the insect rhodnius prolixus stahl

Ramos, Isabela Barbosa; Gomes, Fabio Mendonça; Koeller, Carolina Macedo; Saito, Katsuharu; Heise, Norton; Masuda, Hatisaburo; Docampo, Roberto; Souza, Wanderley de; Machado, Ednildo de Alcântara; Miranda, Kildare Rocha de
Fonte: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia Publicador: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia
Tipo: Artigo de Revista Científica
Português
11 p. : il.; Background: The yolk of insect eggs is a cellular domain specialized in the storage of reserve components for embryo development. The reserve macromolecules are stored in different organelles and their interactions with the embryo cells are mostly unknown. Acidocalcisomes are lysosome-related organelles characterized by their acidic nature, high electron density and large content of polyphosphate bound to several cations. In this work, we report the presence of acidocalcisome-like organelles in eggs of the insect vector Rhodnius prolixus. Methodology/Principal findings: Characterization of the elemental composition of electron-dense vesicles by electron probe X-ray microanalysis revealed a composition similar to that previously described for acidocalcisomes. Following subcellular fractionation experiments, fractions enriched in acidocalcisomes were obtained and characterized. Immunofluorescence showed that polyphosphate polymers and the vacuolar proton translocating pyrophosphatase (V-H+-PPase, considered as a marker for acidocalcisomes) are found in the same vesicles and that these organelles are mainly localized in the egg cortex. Polyphosphate quantification showed that acidocalcisomes contain a significant amount of polyphosphate detected at day-0 eggs. Elemental analyses of the egg fractions showed that 24.560.65% of the egg calcium are also stored in such organelles. During embryogenesis...

‣ Inorganic polyphosphates are stored in spherites within the midgut of Anticarsia gemmatalis and play a role in copper detoxification

Gomes, Fabio Mendonça; Carvalho, Daniela Palermo de; Peron, Antonio Cezar; Saito, Kunihiro; Miranda, Kildare Rocha de; Machado, Ednildo de Alcântara
Fonte: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia Publicador: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia
Tipo: Artigo de Revista Científica
Português
9 p. : il.; Inorganic polyphosphates (PolyP) are widespread molecules that have been shown to play a role in metal detoxification and heavy-metal tolerance. In the present report, we investigated the functional role of spherites as PolyP-metal binding stores in epithelial cells of the midgut of Anticarsia gemmatalis, a lepidopteran pest of soybean. PolyP stores were detected by DAPI staining and indirect immunohistochemistry as vesicles distributed in columnar cells and around goblet cell cavities. These PolyP vesicles were identified as spherites by their elemental profile in cell lysates that were partially modulated by P- or VATPases. PolyP levels along the midgut were detected using a recombinant exopolyphosphatase assay. When copper was added in the diet of larva, copper detection in spherites by X-ray microanalysis correlated with an increase in the relative phosphorous X-ray signal and with an increase in PolyP levels in epithelia cell lysate. Transmission electron microscopy of chemically fixed or cryofixed and freeze substituted tissues confirmed a preferential localization of spherites around the goblet cell cavity. Taken together, these results suggest that spherites store high levels of PolyP that are modulated during metal uptake and detoxification. The similarity between PolyP granules and spherites herein described also suggest that PolyP is one of the main phosphorous source of spherites found in different biological models. This suggests physiological roles played by spherites in the midgut of arthropods and mechanisms involved in heavy metal resistance among different insect genera.

‣ Gut bacterial communities in the giant land snail achatina fulica and their modification by sugarcane-based diet

Cardoso, Alexander Machado; Cavalcante, Janaina Japiassu de Vasconcelos; Vieira, Ricardo Pilz; Lima, Joyce Lemos; Grieco, Maria Angela Bernardes; Clementino, Maysa Beatriz Mandetta; Vasconcelos, Ana Tereza Ribeiro de; Garcia, Eloi de Souza; Souza, Wanderl
Fonte: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia Publicador: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia
Tipo: Artigo de Revista Científica
Português
6 p. : il.; The invasive land snail Achatina fulica is one of the most damaging agricultural pests worldwide representing a potentially serious threat to natural ecosystems and human health. This species is known to carry parasites and harbors a dense and metabolically active microbial community; however, little is known about its diversity and composition. Here, we assessed for the first time the complexity of bacterial communities occurring in the digestive tracts of field-collected snails (FC) by using culture-independent molecular analysis. Crop and intestinal bacteria in FC were then compared to those from groups of snails that were reared in the laboratory (RL) on a sugarcane-based diet. Most of the sequences recovered were novel and related to those reported for herbivorous gut. Changes in the relative abundance of Bacteroidetes and Firmicutes were observed when the snails were fed a high-sugar diet, suggesting that the snail gut microbiota can influence the energy balance equation. Furthermore, this study represents a first step in gaining a better understanding of land snail gut microbiota and shows that this is a complex holobiont system containing diverse, abundant and active microbial communities.

‣ Nanotecnologia: pedidos de patentes depositados no Brasil

Loureiro, Isabel Moniz Aragão de Lemos
Fonte: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia Publicador: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia
Tipo: Relatório Técnico / Report
Português
32 p. : il; O objetivo deste estudo é elaborar um panorama sobre a situação da nanotecnologia no Brasil no período 2006-2008, através dos registros das patentes residentes e não residentes,identificando os domínios/subdomínios mais patenteados, e avaliando também a participação relativa de países, instituições e empresas no desenvolvimento destas tecnologias. Os periódicos científicos existentes, que publicaram artigos em nanotecnologia no mundo neste mesmo período também foram analisados, onde identificamos os principais periódicos,instituições e países que apresentam maior número de publicações em nanotecnologia.

‣ Effect of topoisomerase inhibitors and DNA-binding drugs on the cell proliferation and ultrastructure of trypanosoma cruzi

Zuma, Aline Araujo; Cavalcanti, Danielle Pereira; Maia, Marina Correia Piqueira; Souza, Wanderley de; Motta, Maria Cristina Machado
Fonte: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia Publicador: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia
Tipo: Artigo de Revista Científica
Português
8 p. : il.; Trypanosomatids present unusual organelles, such as the kinetoplast that contains the mitochondrial DNA arranged in catenated circles. The nucleus of these protozoa presents distinct domains during interphase as well as a closed mitosis.DNAtopoisomerases modulate the topological state ofDNAby regulating supercoiling of the double-stranded DNA during replication, transcription, recombination and repair. Because topoisomerases play essential roles in cellular processes, they constitute a potential target for antitumour and antimicrobial drugs. In this study, the effects of various topoisomerase inhibitors and DNA-binding drugs were tested on the cellular proliferation and ultrastructure of the Trypanosoma cruzi epimastigote form Blastocrithidia culicis was used as a comparative model, which has a more relaxed kinetoplast DNA (kDNA) organization. The results showed that the eukaryotic topoisomerase I inhibitors camptothecin and rebeccamycin were the most effective compounds in the arrest of T. cruzi proliferation. Of the eukaryotic topoisomerase II inhibitors, mitoxantrone, but not merbarone, was effective against cell proliferation. The prokaryotic topoisomerase II inhibitors norfloxacin and enoxacin targeted the kinetoplast specifically...

‣ High throughput screening of hydrolytic enzymes from termites using a natural substrate derived from sugarcane bagasse

Lucena Neto, Severino de Albuquerque; Lima, Leile de Souza; Cordeiro Junior, Luís Sergio de Araujo; Sant’Anna, Celso; Constantino, Reginaldo; Penna, Patrícia de Azambuja; Souza, Wanderley de; Garcia, Eloi de Souza
Fonte: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia Publicador: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia
Tipo: Artigo de Revista Científica
Português
9 p. : il.; Background: The description of new hydrolytic enzymes is an important step in the development of techniques which use lignocellulosic materials as a starting point for fuel production. Sugarcane bagasse, which is subjected to pre-treatment, hydrolysis and fermentation for the production of ethanol in several test refineries, is the most promising source of raw material for the production of second generation renewable fuels in Brazil. One problem when screening hydrolytic activities is that the activity against commercial substrates, such as carboxymethylcellulose, does not always correspond to the activity against the natural lignocellulosic material. Besides that, the macroscopic characteristics of the raw material, such as insolubility and heterogeneity, hinder its use for high throughput screenings. Results: In this paper, we present the preparation of a colloidal suspension of particles obtained from sugarcane bagasse, with minimal chemical change in the lignocellulosic material, and demonstrate its use for high throughput assays of hydrolases using Brazilian termites as the screened organisms. Conclusions: Important differences between the use of the natural substrate and commercial cellulase substrates, such as carboxymethylcellulose or crystalline cellulose...

‣ A new approach to improve the quality of ultrathin cryo-sections; its use for immunogold EM and correlative electron cryo-tomography

Bos, Erik; Sant’Anna, Celso; Gnaegi, Helmut; Pinto, Roberta Fernandes; Ravelli, Raimond; Koster, Abraham; Souza, Wanderley de; Peters, Peter
Fonte: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia Publicador: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia
Tipo: Artigo de Revista Científica
Português
11 p. : il.; Cryo-ultramicrotomy can be used to obtain ultrathin cryo-sections from cryo-fixed or aldehyde-fixed cryo-protected vitreous biologic samples. For immuno-gold EM, cryo-sections are retrieved from the cryo-chamber on a droplet of a pick-up solution (paste-like and almost frozen) to which the sections attach. The sections are then placed on an EM specimen grid at room temperature. This procedure compromises the ultrastructure, resulting in folds, holes, and loss of the original material. In this paper we show the critical influence of humidity, stretching, and relief of compression during thawing of the sections. We show a new lift-up hinge device for semi-automated retrieval of cryo-sections that results in significantly improved section quality. This approach was also applied successfully to vitreous sections from high pressure frozen samples. An important advance is that these vitreous cryo-sections can now successfully be post-fixed and immunolabelled after thawing; this allows cryo-EM comparison with adjacent ribbons of sections still in the frozen hydrated state. These findings call for technical innovations aiming at automated cryo-ultramicrotomy in a fully controlled environment for improved localization of proteins within their ‘close to native’ cellular context and correlative electron cryo-tomography of consecutive ribbons of sections of one frozen hydrated sample.

‣ Trypanosoma cruzi epimastigotes are able to store and mobilize high amounts of cholesterol in reservosome lipid inclusions

Pereira, Miria Gomes; Nakayasu, Ernesto Satoshi; Sant’Anna, Celso; Cicco, Nuccia Nicole Theodoro de; Atella, Geórgia Corrêa; Souza, Wanderley de; Almeida, Igor Correia de; Silva, Narcisa Leal da Cunha e
Fonte: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia Publicador: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia
Tipo: Artigo de Revista Científica
Português
12 p. : il.; Background: Reservosomes are lysosome-related organelles found in Trypanosoma cruzi epimastigotes. They represent the last step in epimastigote endocytic route, accumulating a set of proteins and enzymes related to protein digestion and lipid metabolism. The reservosome matrix contains planar membranes, vesicles and lipid inclusions. Some of the latter may assume rectangular or sword-shaped crystalloid forms surrounded by a phospholipid monolayer, resembling the cholesterol crystals in foam cells. Methodology/Principal Findings: Using Nile Red fluorimetry and fluorescence microscopy, as well as electron microscopy, we have established a direct correlation between serum concentration in culture medium and the presence of crystalloid lipid inclusions. Starting from a reservosome purified fraction, we have developed a fractionation protocol to isolate lipid inclusions. Gas-chromatography mass-spectrometry (GC-MS) analysis revealed that lipid inclusions are composed mainly by cholesterol and cholesterol esters. Moreover, when the parasites with crystalloid lipid-loaded reservosomes were maintained in serum free medium for 48 hours the inclusions disappeared almost completely, including the sword shaped ones. Conclusions/Significance: Taken together...

‣ Hyperosmotic stress induces aquaporin-dependent cell shrinkage, polyphosphate synthesis, amino acid accumulation, and global gene expression changes in trypanosoma cruzi

Li, Zhu-Hong; Alvarez, Vanina; Gaudenzi, Javier; Sant’Anna, Celso; Frasch, Alberto; Cazzulo, Juan Jose; Docampo, Roberto
Fonte: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia Publicador: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia
Tipo: Artigo de Revista Científica
Português
13 p. : il.; Background: Trypanosoma cruzi is subjected to hyperosmotic stress during its life cycle. Results: The recovery from hyperosmotic stress involves the function of an aquaporin, amino acid accumulation, polyphosphate synthesis, and global gene regulation. Conclusion: The response to hyperosmotic stress is different from that observed in mammalian cells or yeasts. Significance: Learning the mechanism of osmoregulation is important for finding new drug targets.