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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‣ Phosphoproteome reveals an atlas of protein signaling networks during osteoblast adhesion

Milani, Renato; Ferreira, Carmen Veríssima; Granjeiro, José Mauro; Paredes Gamero, Edgar Julian; Silva, Rodrigo Augusto da; Justo, Giselle Zenker; Nader, Helena Bonciani; Galembeck, Eduardo; Peppelenbosch, Maikel P.; Aoyama, Hiroshi; Zambuzzi, Willian F
Fonte: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia Publicador: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia
Tipo: Artigo de Revista Científica
Português
10 p. : il.; Cell adhesion on surfaces is a fundamental process in the emerging biomaterials field and developmental events as well. However, the mechanisms regulating this biological process in osteoblasts are not fully understood. Reversible phosphorylation catalyzed by kinases is probably the most important regulatory mechanism in eukaryotes. Therefore, the goal of this study is to assess osteoblast adhesion through a molecular prism under a peptide array technology, revealing essential signaling proteins governing adhesion-related events. First, we showed that there are main morphological changes on osteoblast shape during adhesion up to 3 h. Second, besides classical proteins activated upon integrin activation, our results showed a novel network involving signaling proteins such as Rap1A, PKA, PKC, and GSK3b during osteoblast adhesion on polystyrene. Third, these proteins were grouped in different signaling cascades including focal adhesion establishment, cytoskeleton rearrangement, and cell-cycle arrest. We have thus provided evidence that a global phosphorylation screening is able to yield a systems-oriented look at osteoblast adhesion, providing new insights for understanding of bone formation and improvement of cell– substratum interactions. Altogether...

‣ Development of secondary palate requires strict regulation of ECM remodeling: sequential distribution of RECK, MMP-2, MMP-3, and MMP-9

Demarchi, Ana Claudia Cardoso de Oliveira; Zambuzzi, Willian Fernando; Paiva, Katiúcia Batista da Silva; Valenzuela, Maria das Graças da Silva; Nunes, Fabio Daumas; Figueira, Rita de Cássia Sávio; Sasahara, Regina Maki; Demasi, Marcos Angelo Almeida;
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.; We have evaluated RECK (reversion-inducingcysteine- rich protein with Kazal motifs), MMP-2 (matrix metalloproteinase-2), MMP-3, and MMP-9 involvement during palate development in mice by using various techniques. Immunohistochemical features revealed the distribution of RECK, MMP-2, and MMP-3 in the mesenchymal tissue and in the midline epithelial seam at embryonic day 13 (E13), MMPs-2, -3, and -9 being particularly expressed at E14 and E14.5. In contrast, RECK was weakly immunostained at these times. Involvement of MMPs was validated by measuring not only their protein expression, but also their activity (zymograms). In situ hybridization signal (ISH) for RECK transcript was distributed in mesenchymal and epithelial regions within palatal shelves at all periods evaluated. Importantly, the results from ISH analysis were in accord with those obtained by real-time polymerase chain reaction. The expression of RECK was found to be temporally regulated, which suggested possible roles in palatal ontogeny. Taken together, our results clearly show that remodeling of the extracellular matrix is finely modulated during secondary palate development and occurs in a sequential manner.

‣ Hydroxyapatite surface solubility and effect on cell adhesion

Bertazzo, Sergio; Zambuzzi, Willian Fernando; Campos, Daniella Dias Palombino de; Ogeda, Thais Lucy; Ferreira, Carmen Veríssima; Bertran, Celso Aparecido
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.; In living organisms the biological hydroxyapatite is in constant contact with body fluids, such as blood serum and saliva. Thus, dissolution, solubility and precipitation take place as part of the interaction of this material with biological fluids in tissues. In this work we have obtained the solubility constant for the system formed from aqueous solutions in equilibrium with hydroxyapatite and thus indirectly obtained the composition of the modified hydroxyapatite surface. In order to check the effects of this equilibrium and of the modification that the surface of hydroxyapatite suffers in aqueous solutions, we cultured pre-osteoblasts onto hydroxyapatite discs before and after equilibrium. The results revealed key steps of the mechanism for the bioactivity of hydroxyapatite, which are the solubilization of hydroxyapatite and the equilibrium that is formed on the surface. These processes modify the hydroxyapatite surface, whose composition is changed to a new calcium phosphate compound with the chemical formula of CaHPO4. A clear description of the transformations that occur on the surface of hydroxyapatite and of the interplay between these transformations and cell activity are two fundamental aspects of processes in which hydroxyapatite takes part...

‣ Chagas’ disease: facts and reality

Souza, Wanderley 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
Despite significant advances obtained in the last 20 years, available data show that infectious and parasitic diseases remain as the biggest killers, accounting for about 25% of the global burden disease. The use of an aggregate measure of premature mortality, morbidity and disability, known as DALYs (disability-adjusted life years), shows elevated indexes for infectious and parasitic diseases in Africa, Southeast Asia and Eastern Mediterranean, with much lower indexes for Western Pacific, the Americas and Europe, following the regions defined by World Health Organization (WHO).

‣ Bioactivation of alumina by surface modification : a possibility for improving the applicability of alumina in bone and oral repair

Zambuzzi, Willian Fernando; Bertazzo, Sergio; Bertran, Celso Aparecido; Silva, H. A. da; Ferreira, Carmen Veríssima
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.; Objectives: In regenerative medicine, surface engineering of bioinert synthetic materials is often required in order to introduce bioactive species that can promote cell adhesion, proliferation, viability and enhanced ECM-secretion functions. The aim of this work is to study cell interaction with alumina-modified surfaces. Material and methods: In this work, chemical properties of alumina surface were changed by a reaction at the surface of alumina with low molecular weight dicarboxylic acid, which produced carboxyl groups. Results: These carboxyl groups were able to complex with Ca2þ on the surface, forming sites of precipitation for calcium phosphates that make alumina biocompatible, as indicated by cell culture of pre-osteoblasts (MC3T3-E1 cell line). Conclusions: The procedure presented in this work shows that the insertion of specific functional groups on the surface of alumina increases cell interaction with the surface of alumina. This knowledge can be important in oral science and orthopedics, for the construction of prosthesis.

‣ Determination of as in vegetable oil and biodiesel by graphite furnace atomic absorption spectrometry

Vieira, Mariana Antunes; Oliveira, Lígia Cláudia Castro de; Gonçalves, Rodrigo Araújo; Souza, Vanderléa de; Campos, Reinaldo Calixto 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
5 p. : il.; In this work, an alternative procedure for the determination of As in vegetable oils and biodiesel of different origins by graphite furnace atomic absorption spectrometry (GFAAS) is proposed. The sample stabilization was achieved by the formation of three component solutions prepared mixing the samples with appropriate volumes of propan-1-ol and nitric acid. Palladium was used as a chemical modifier. Pyrolysis and atomization temperatures as well as the sample dilution factor were investigated and optimized. Because no adequate certified reference material was available, accuracy was assessed by recovery tests, using both organic and inorganic species. Recoveries ranged from 95 to 110%. The limit of detection in the original sample was 0.3 mg kg-¹, which is adequate for the analysis of vegetable oils and biodiesel, according to the expected Brazilian legislation.

‣ Fine structure of phloematic trypanosomatid–coconut tree interaction

Cunha, Maura da; Keller, Darlí Grativol; Bustamante Filho, Ivan Cunha; Magalhães, Jorge André Sacramento de; Gomes, Valdirene Moreira; Souza, Wanderley de; Moura, José Inácio Lacerda
Fonte: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia Publicador: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia
Tipo: Artigo de Revista Científica
Português
10 p. : il.; Phytomonas wilt or Hartrot is a fatal disease of palm (Arecaceae) species including Cocos nucifera (coconut) and is caused by a phloematic trypanosomatid, a promastigote parasite that inhabits phloem sieve elements of disease palms. In the present work, we described the morphology of the interaction between a phloematic trypanosomati (Phytomonas staheli) and C. nucifera. Two varieties and one ecotype of the adult coconut palm from northeast and southeast Brazil were analyzed, totaling 34,000 plants. Coconut palm losses due to Hartrot varied according to the variety or ecotype and geographic area. Occurrence of Hartrot was insignificant in Rio de Janeiro state (southeast), but in Bahia state (northeast) losses were substantial when appropriate cultural practices were not applied. Symptomatic and healthy palm tissues were analyzed by light and electron microscopy. Laboratory diagnoses revealed the twisted promastigote form of phloematic trypanosomatids in the extracts of shoot apex, leaves, stems and inflorescence in diseased plants, but not in the healthy ones. No parasites were found in the roots. Although the general anatomy of healthy and diseased palms was similar, callose deposition in the sieve plates was revealed by histochemistry and immunocytochemistry in the diseased tissue. Plugging by the P-protein and plastid alterations was also observed. Our observations strongly suggest that parasite traffic between sieve elements took place...

‣ Electron microscopy of trypanosomes : a historical view

Souza, Wanderley 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
13 p. : il.; Since the discovery of the electron microscope and the development of the initial techniques for the processing of biological samples for electron microscopy, the protozoan Trypanosoma cruzi has been the subject of intense investigation. This review analyzes the results obtained by observation of whole trypanosomes as well as thin sections and replicas using several microscopic approaches. Micrographs detailing the appearance of T. cruzi using several methods illustrate the evolution of electron microscopic techniques as well as its contribution to understanding the structural organization of the protozoan.

‣ Development of a simple and rapid agrobacterium tumefaciens-mediated transformation system for the entomopathogenic fungus Metarhizium anisopliae var. acridum

Duarte, Rubens Tadeu Delgado; Staats, Charley Christian; Fungaro, Maria Helena Pelegrinelli; Schrank, Augusto; Vainstein, Marilene Henning; Maia, Luciana Furlaneto; Nakamura, Celso Vataru; Souza, Wanderley de; Furlaneto, Márcia Cristina
Fonte: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia Publicador: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia
Tipo: Artigo de Revista Científica
Português
7 p. : il.; Aims: To examine the ability of Agrobacterium to attach to Metarhizium anisopliae var. acridum strain CG423 under co-cultivation and to develop an Agrobacterium- mediated method of gene delivery into strain CG423, a promising agent for biological control of grasshoppers. Methods and Results: The co-cultivation of Agrobacterium tumefaciens and M. anisopliae var. acridum was analysed under scanning electron microscopy. We observed that Agrobacterium attached to and formed aggregates around Metarhizium conidia and germ tubes. We also observed the occurrence of fibril-like structures connecting neighbouring bacterial–fungal cells. The Agrobacterium- mediated transformation was applied using two binary vectors carrying a benomyl resistance gene as a selection marker. The efficiency of transformation was up to 53 transformants per 105 target conidia. High mitotic stability of the transformants (89–97%) was demonstrated after five successive transfers on non-selective media. Molecular analysis revealed the occurrence of high frequency of gene conversion. Conclusions: In our study, we report that A. tumefaciens strain AGL-1 attaches to and genetically transforms the entomopathogenic fungus Metarhizium anisopliae var. acridum. Significance and Impact of the Study: We report for the first time...

‣ Complete genome sequence of the sugarcane nitrogen-fixing endophyte gluconacetobacter diazotrophicus PAL5

Bertalan, Marcelo; Albano, Rodolpho Mattos; Pádua, Vânia Lúcia Muniz de; Rouws, Luc; Rojas, Cristian; Hemerly, Adriana Silva; Teixeira, Katia Regina dos Santos; Schwab, Stefan; Araujo, Jean Luiz Simões de; Oliveira, André Lopes de; França, Leonardo;
Fonte: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia Publicador: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia
Tipo: Artigo de Revista Científica
Português
17 p. : il.; Background: Gluconacetobacter diazotrophicus Pal5 is an endophytic diazotrophic bacterium that lives in association with sugarcane plants. It has important biotechnological features such as nitrogen fixation, plant growth promotion, sugar metabolism pathways, secretion of organic acids, synthesis of auxin and the occurrence of bacteriocins. Results: Gluconacetobacter diazotrophicus Pal5 is the third diazotrophic endophytic bacterium to be completely sequenced. Its genome is composed of a 3.9 Mb chromosome and 2 plasmids of 16.6 and 38.8 kb, respectively. We annotated 3,938 coding sequences which reveal several characteristics related to the endophytic lifestyle such as nitrogen fixation, plant growth promotion, sugar metabolism, transport systems, synthesis of auxin and the occurrence of bacteriocins. Genomic analysis identified a core component of 894 genes shared with phylogenetically related bacteria. Gene clusters for gum-like polysaccharide biosynthesis, tad pilus, quorum sensing, for modulation of plant growth by indole acetic acid and mechanisms involved in tolerance to acidic conditions were identified and may be related to the sugarcane endophytic and plant-growth promoting traits of G. diazotrophicus. An accessory component of at least 851 genes distributed in genome islands was identified...

‣ Desenvolvimento de material de referência certificado: etanol em água – um caso prático

Souza, Vanderléa de; Caixeiro, Janaína Marques Rodrigues; Silva, Rafael Agostinho Lemos da; Pedro, Leandro Rodrigues; Borges, Renata Martins Horta; Couto, Paulo Roberto Guimarães
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
6 p. : il.; O presente trabalho descreve o desenvolvimento de um material de referência certificado (MRC) referente a soluções de etanol em água em cinco concentrações diferentes, abordando todas as etapas necessárias para o desenvolvimento de um MRC, conforme prescreve as ISO GUIDE 30, 31, 32, 33, 34 e 35. O desenvolvimento deste MRC originou-se nas determinações da Portaria Inmetro n° 006 de 2002, que assegura que todos os etilômetros a serem utilizados no Brasil deverão ter os seus modelos aprovados, e as verificações realizadas a partir de ensaios com soluções de etanol em água. Desta forma, o desenvolvimento deste MRC contribui de forma significativa, para a rastreabilidade ao Sistema Internacional de Unidades (SI) e confiabilidade nas medições realizadas com etilômetros, uma vez que as soluções utilizadas possuem rastreabilidade ao SI, tendo incerteza de medição declarada. Outro ponto importante é que a partir deste desenvolvimento, possibilita-se a sociedade um MRC que pode ter aplicações variadas, não se restringindo somente a ensaios com etilômetros.

‣ Calcium- and polyphosphate-containing acidic granules of sea urchin eggs are similar to acidocalcisomes, but are not the targets for NAADP

Ramos, Isabela Barbosa; Miranda, Kildare Rocha de; Pace, Douglas A.; Verbist, Katherine C.; Lin, Fu-Yang; Zhang, Yonghui; Oldfield, Eric; Machado, Ednildo de Alcântara; Souza, Wanderley de; Campo, Roberto do
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.; Acidocalcisomes are acidic calcium-storage compartments described from bacteria to humans and characterized by their high content in poly P (polyphosphate), a linear polymer ofmany tens to hundreds of Pi residues linked by high-energy phosphoanhydride bonds. In the present paper we report that millimolar levels of short-chain poly P (in terms of Pi residues) and inorganic PPi are present in sea urchin extracts as detected using 31P-NMR, enzymatic determinations and agarose gel electrophoresis. Poly P was localized to granules randomly distributed in the sea urchin eggs, as shown by labelling with the poly-P-binding domain of Escherichia coli exopolyphosphatase. These granules were enriched using iodixanol centrifugation and shown to be acidic and to contain poly P, as determined by Acridine Orange and DAPI (4 ,6 -diamidino-2-phenylindole) staining respectively. These granules also contained large amounts of calcium, sodium, magnesium, potassium and zinc, as detected by X-ray microanalysis, and bafilomycin A1-sensitive ATPase, pyrophosphatase and exopolyphosphatase activities, as well as Ca2+/H+ and Na+/H+ exchange activities, being therefore similar to acidocalcisomes described in other organisms. Calcium release from these granules induced by nigericin was associated with poly P hydrolysis. Although NAADP (nicotinic acid–adenine dinucleotide phosphate) released calcium from the granule fraction...

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

Terra, Letícia Labati; Andrade, Loraine Campanati Araujo de; Souza, Wanderley 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
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.

‣ Calcium- regulated fusion of yolk granules is important for yolk degradation during early embryogenesis of Rhodnius prolixus Stahl

Ramos, Isabela Barbosa; Miranda, Kildare Rocha de; Souza, Wanderley de; Santos, Danielle Maria Perpétua de Oliveira; Lima, Ana Paula Cabral de Araújo; Sorgine, Marcos Henrique Ferreira; 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 examined the process of membrane fusion of yolk granules (YGs) during early embryogenesis of Rhodnius prolixus. We show that eggs collected at days·0 and 3 after oviposition contain different populations of YGs, for example day-3 eggs are enriched in large YGs (LYGs). Day-3 eggs also contain the highest free [Ca2+] during early embryogenesis of this insect. In vitro incubations of day-0 YGs with [Ca2+] similar to those found in day-3·eggs resulted in the formation of LYGs, as observed in vivo. Fractionation of LYGs and small YGs (SYGs) and their subsequent incubation with the fluorescent membrane marker PKH67 showed a calciumdependent transference of fluorescence from SYGs to LYGs, possibly as the result of membrane fusion. Acid phosphatase and H+-PPase activities were remarkably increased in day-3 LYGs and in calcium-treated day-0 LYGs. Both fractions were found to contain vitellins as major components, and incubation of YGs with calcium induced yolk proteolysis in vitro. Altogether, our results suggest that calcium-induced membrane fusion events take part in yolk degradation, leading to the assembly of the yolk mobilization machinery.

‣ Trypanosoma rangeli: a new perspective for studying the modulation of immune reactions of Rhodnius prolixus

Garcia, Eloi de Souza; Castro, Daniele Pereira de; Figueiredo, Marcela Barbosa de; Genta, Fernando Ariel; Penna, Patrícia de Azambuja
Fonte: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia Publicador: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia
Tipo: Artigo de Revista Científica
Português
10 p. : il.; Insects are exposed to a wide range of microorganisms (bacteria, fungi, parasites and viruses) and have interconnected powerful immune reactions. Although insects lack an acquired immune system they have well-developed innate immune defences that allow a general and rapid response to infectious agents. Over the last few decades we have observed a dramatic increase in the knowledge of insect innate immunity, which relies on both humoral and cellular responses. However, innate reactions to natural insect pathogens and insect-transmitted pathogens, such as parasites, still remain poorly understood. In this review, we briefly introduce the general immune system of insects and highlight our current knowledge of these reactions focusing on the interactions of Trypanosoma rangeli with Rhodnius prolixus, an important model for innate immunity investigation.

‣ In vitro activities of ER-119884 and E5700, two potent squalene synthase inhibitors, against leishmania amazonensis: antiproliferative, biochemical, and ultrastructural effects

Rodrigues, Juliany Cola Fernandes; Concepcion, Juan L.; Rodrigues, Carlos; Caldera, Aura; Urbina, Julio A.; Souza, Wanderley 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
17 p. : il.; ER-119884 and E5700, novel arylquinuclidine derivatives developed as cholesterol-lowering agents, were potent in vitro growth inhibitors of both proliferative stages of Leishmania amazonensis, the main causative agent of cutaneous leishmaniasis in South America, with the 50% inhibitory concentrations (IC50s) being in the low nanomolar to subnanomolar range. The compounds were very potent noncompetitive inhibitors of native L. amazonensis squalene synthase (SQS), with inhibition constants also being in the nanomolar to subnanomolar range. Growth inhibition was strictly associated with the depletion of the parasite’s main endogenous sterols and the concomitant accumulation of exogenous cholesterol. Using electron microscopy, we identified the intracellular structures affected by the compounds. A large number of lipid inclusions displaying different shapes and electron densities were observed after treatment with both SQS inhibitors, and these inclusions were associated with an intense disorganization of the membrane that surrounds the cell body and flagellum, as well as the endoplasmic reticulum and the Golgi complex. Cells treated with ER-119884 but not those treated with E5700 had an altered cytoskeleton organization due to an abnormal distribution of tubulin...

‣ Use of Cathorops spixii as bioindicator of pollution of trace metals in the Santos Bay, Brazil

Souza, Juliana Azevedo de; Braga, Elisabete de Santis; Fernandez, Wellinton Silva; Farias, Luciana Aparecida; Fávaro, Deborah Ines Teixeira
Fonte: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia Publicador: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia
Tipo: Artigo de Revista Científica
Português
1 p.; In the present study Cathorops spixii, was evaluated as a bioindicator fish for trace metal pollution. Concentrations of cobalt (Co), iron (Fe), selenium (Se) and zinc (Zn) were determined by Instrumental Neutron Activation Analysis in liver. Mercury (Hg) and methyl-mercury (MeHg) were analyzed by Cold Vapor Atomic Absorption Spectrometry in muscles and livers.High concentrations ofCo, Fe, Se and Zn were observed in C. spixii from Santos Bay in comparison to fish collected in a non-polluted site in the same Brazilian coast. These trace metal concentrations were out of the permissible levels for human consumption. Although, Hg andMeHg levels were low, the C. spixii could still be used as an effective bioindicator to observe trace metal behaviors in the environment in function of the bioaccumulation process observed mainly by other analyzed trace metals. Thus, the use of this species is strongly recommended tomonitor the effects and behavior of trace metal pollution in aquatic ecosystems in Brazil due to its bioaccumulation function.

‣ Dynamin inhibitor impairs Toxoplasma gondii invasion

Caldas, Lucio Ayres; Attias, Márcia; Souza, Wanderley 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
6 p. : il.; The protozoan parasite Toxoplasma gondii infects its host cells through an active mechanism. In this work, we obtained evidence that host cells also play a fundamental role during the infection process.We found that previous incubation of the host cells, but not the parasites, with Dynasore, a small molecule that inhibits dynamin GTPase activity, markedly reduced the penetration of T. gondii tachyzoites into LLC-MK2 cells. In contrast, parasite adhesion to the host cell surface increased, as observed both by light and electron microscopy. Intriguingly, the few parasites internalized by Dynasore-treated cells remained in vacuoles located at the periphery of the cell, in contrast to the perinuclear localization seen in the control.

‣ Early and late pathogenic events of newborn mice encephalitis experimentally induced by itacaiunas and curionoópolis bracorhabdoviruses infection

Diniz, José Antonio Picanço; Santos, Zaire Alves dos; Braga, Marcio Augusto Galvão; Dias, Ádila Liliane Barros; Silva, Daisy Elaine Andrade da; Medeiros, Daniele Barbosa de Almeida; Barros, Vera Lucia Reis de Souza; Chiang, Jannifer Oliveira; Zoghbi,
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.; In previous reports we proposed a new genus for Rhabdoviridae and described neurotropic preference and gross neuropathology in newborn albino Swiss mice after Curionopolis and Itacaiunas infections. In the present report a timecourse study of experimental encephalitis induced by Itacaiunas and Curionopolis virus was conducted both in vivo and in vitro to investigate cellular targets and the sequence of neuroinvasion. We also investigate, after intranasal inoculation, clinical signs, histopathology and apoptosis in correlation with viral immunolabeling at different time points. Curionopolis and Itacaiunas viral antigens were first detected in the parenchyma of olfactory pathways at 2 and 3 days post-inoculation (dpi) and the first clinical signs were observed at 4 and 8 dpi, respectively. After Curionopolis infection, the mortality rate was 100% between 5 and 6 dpi, and 35% between 8 and 15 dpi after Itacaiunas infection. We identified CNS mice cell types both in vivo and in vitro and the temporal sequence of neuroanatomical olfactory areas infected by Itacaiunas and Curionopolis virus. Distinct virulences were reflected in the neuropathological changes including TUNEL immunolabeling and cytopathic effects, more intense and precocious after intracerebral or in vitro inoculations of Curionopolis than after Itacaiunas virus. In vitro studies revealed neuronal but not astrocyte or microglial cytopathic effects at 2 dpi...

‣ High temperatures enhance cooperative motions between CBM and catalytic domains of a thermostable cellulase: mechanism insights from essential dynamics

Batista, Paulo Ricardo; Costa, Mauricio Garcia de Souza; Pascutti, Pedro Geraldo; Bisch, Paulo Mascarello; Souza, Wanderley 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
12 p. : il.; Cellulases from thermophiles are capable of cleaving sugar chains from cellulose efficiently at high temperatures. The thermo-resistant Cel9A-68 cellulase possesses two important domains: CBM and a catalytic domain connected by a Pro/Ser/Thr rich linker. These domains act cooperatively to allow efficient catalysis. Despite exhaustive efforts to characterize cellulase binding and mechanism of action, a detailed description of the cellulose intrinsic flexibility is still lacking. From computational simulations we studied the temperature influence on the enzyme plasticity, prior to substrate binding. Interestingly, we observed an enhancement of collective motions at high temperatures. These motions are the most representative and describe an intrinsic hinge bending transition. A detailed analysis of these motions revealed an interdomain approximation where D459 and G460, located at the linker region, are the hinge residues. Therefore, we propose a new putative site for mutagenesis targeting the modulation of such conformational transition that may be crucial for activity.