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Search Results: 1 - 10 of 262073 matches for " Marcelo N.;Silva-Neto "
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Oogenesis and egg development in triatomines: a biochemical approach
Atella, Georgia C.;Gondim, Katia C.;Machado, Ednildo A.;Medeiros, Marcelo N.;Silva-Neto, Mário A.C.;Masuda, Hatisaburo;
Anais da Academia Brasileira de Ciências , 2005, DOI: 10.1590/S0001-37652005000300005
Abstract: in triatomines, as well as in other insects, accumulation of yolk is a process in which an extra-ovarian tissue, the fat body, produces yolk proteins that are packed in the egg. the main protein, synthesized by the fat body, which is accumulated inside the oocyte, is vitellogenin. this process is also known as vitellogenesis. there are growing evidences in triatomines that besides fat body the ovary also produces yolk proteins. the way these yolk proteins enter the oocyte will be discussed. yolk is a complex material composed of proteins, lipids, carbohydrates and other minor components which are packed inside the oocyte in an organized manner. fertilization triggers embryogenesis, a process where an embryo will develop. during embryogenesis the yolk will be used for the construction of a new individual, the first instar nymph. the challenge for the next decade is to understand how and where these egg proteins are used up together with their non-protein components, in pace with the genetic program of the embryo, which enables cell differentiation (early phase of embryogenesis) and embryo differentiation (late phase) inside the egg.
Primeiro Registro de Ectopsocus titschacki Jentsch (Psocodea: Psocoptera: Ectopsocidae) para o Estado da Bahia: Uma Prova da Falta de Estudos nessa Ordem de Insecta no Brasil First Record of Ectopsocus titschacki Jentsch (Psocodea: Psocoptera: Ectopsocidae) in Bahia State: Proof of a Lack of Studies on this Order of Insecta in Brazil
Alberto Moreira Silva-Neto,Freddy Bravo,Alfonso N. García Aldrete
EntomoBrasilis , 2013, DOI: 10.12741/ebrasilis.v6i1.198
Abstract: Nesse trabalho realizamos o primeiro registro de Ectopsocus titschacki Jentsch para o Estado da Bahia, incluindo alguns comentários sobre a atual situa o do conhecimento e da distribui o dessa ordem de Insecta no Brasil evidenciando a lacuna de conhecimento desse grupo em alguns estados especialmente aqueles pertencentes à regi o Nordeste. In this paper we report the first record of Ectopsocus titschacki Jentsch for the State of Bahia, including some comments on the current state of knowledge and distribution of this order of Insecta in Brazil showing the knowledge gap that group in some states especially those belonging to Northeast.
One-loop dimensional reduction of the linear sigma model
A. P. C. Malbouisson,M. B. Silva-Neto,N. F. Svaiter
Physics , 1997, DOI: 10.1016/S0378-4371(97)00560-8
Abstract: We perform the dimensional reduction of the linear $\sigma$ model at one-loop level. The effective potential of the reduced theory obtained from the integration over the nonzero Matsubara frequencies is exhibited. Thermal mass and coupling constant renormalization constants are given, as well as the thermal renormalization group equation which controls the dependence of the counterterms on the temperature. We also recover, for the reduced theory, the vacuum unstability of the model for large N.
Ethanol Intake during Lactation Alters Milk Nutrient Composition and Growth and Mineral Status of Rat Pups
CíNTIA R.P AZARA,INGRID C MAIA,CAROLINA N RANGEL,MáRIO A.C SILVA-NETO
Biological Research , 2008,
Abstract: Lactating Wistar rats were fed a liquid diet containing either ethanol [ethanol-fed group (EFG)] or an isocaloric amount of carbohydrate [pair-fed group (PFG)] from day 1 postpartum up to day 14 of lactation, to investigate micro/macronutrient milk composition and the mineral status of pups. EFG presented a reduction of daily milk production and milk composition was significantly higher in protein and lower in carbohydrate, while the lipid content was similar to that of PFG. When compared to PFG, the milk of EFG had a decreased proportion of C22:6 n-3 fatty acid and an increase in medium-chain fatty acids and of several minerals. Pups of EFG showed reduced growth and a lower concentration of Cu and Sr in plasma and lower concentrations of Ca, P and Cl, and higher concentrations of Cd in the brain. We conclude that maternal EtOH intake greatly impairs lactational performance and modifies the mineral status of pups.
Improvement of silver impregnation technique (Protargol) to obtain morphological features of protists ciliates, flagellates and opalinates
SILVA-NETO, I. D. da;
Revista Brasileira de Biologia , 2000, DOI: 10.1590/S0034-71082000000300010
Abstract: the research on ciliates, flagelates and opalinates have been widespread by the utilization of techniques employing silver impregnation (protargol), modified by several authors. however, these are time consuming and its results are variable. the present work is a variant of the technique described by tuffrau (1964, 1967) showing some adaptations made in our laboratory. the organisms can be preserved by different fixatives (alcoholic bouin, stieve's fluid, 2.5% glutaraldehyde and others) and then rinsed in destilled water followed by a fast clarification by 3% sodium hypochloride. if the organism is very sensitive to hypochloride, 4% sodium lauryl sulfate may be used and then washed 3 times in distilled water. the protista can be adhered to the glass slides with mayer's glycerinated-albumin (1 glycerin vol. to 1 or 2 albumin vol.), diluted in water at a proportion of 1:10 cv/v., or with 1% polylysine followed by fast washes with distilled water. after the slide preparation, they were covered with a layer of 0,8% silver proteinate. right after that, the slide has to be placed in a glass tray lined with moist tissue and covered to prevent the proteinate to dry. the tray was placed in a incubator at 40o-50oc for 30 minutes. the slides are rinsed for 1 minute. with warm (35oc) distilled water. the development of the material should be done with 0.4% hydroquinone with a maximum incubation time of 1 minute. it should be developed gradually, controlling the silver impregnation intensity by observation under optical microscope. next, rinse in distilled water for 1 minute, and then, fix in 2,5% sodium thiosulfate. rinse the slide for two minutes before dehydrating it in an alcoholic serial 50-100o. finally rinse the slides in xylene. mount the slides with entellan mercktm or canada balsam.
Improvement of silver impregnation technique (Protargol) to obtain morphological features of protists ciliates, flagellates and opalinates
SILVA-NETO I. D. da
Revista Brasileira de Biologia , 2000,
Abstract: The research on ciliates, flagelates and opalinates have been widespread by the utilization of techniques employing silver impregnation (Protargol), modified by several authors. However, these are time consuming and its results are variable. The present work is a variant of the technique described by Tuffrau (1964, 1967) showing some adaptations made in our laboratory. The organisms can be preserved by different fixatives (alcoholic Bouin, Stieve's fluid, 2.5% glutaraldehyde and others) and then rinsed in destilled water followed by a fast clarification by 3% sodium hypochloride. If the organism is very sensitive to hypochloride, 4% sodium lauryl sulfate may be used and then washed 3 times in distilled water. The protista can be adhered to the glass slides with Mayer's glycerinated-albumin (1 glycerin vol. to 1 or 2 albumin vol.), diluted in water at a proportion of 1:10 Cv/v., or with 1% polylysine followed by fast washes with distilled water. After the slide preparation, they were covered with a layer of 0,8% Silver proteinate. Right after that, the slide has to be placed in a glass tray lined with moist tissue and covered to prevent the proteinate to dry. The tray was placed in a incubator at 40o-50oC for 30 minutes. The slides are rinsed for 1 minute. with warm (35oC) distilled water. The development of the material should be done with 0.4% hydroquinone with a maximum incubation time of 1 minute. It should be developed gradually, controlling the silver impregnation intensity by observation under optical microscope. Next, rinse in distilled water for 1 minute, and then, fix in 2,5% Sodium thiosulfate. Rinse the slide for two minutes before dehydrating it in an alcoholic serial 50-100o. Finally rinse the slides in xylene. Mount the slides with Entellan MerckTM or Canada balsam.
An Insight into the Transcriptome of the Digestive Tract of the Bloodsucking Bug, Rhodnius prolixus
José M. C. Ribeiro ,Fernando A. Genta,Marcos H. F. Sorgine,Raquel Logullo,Rafael D. Mesquita,Gabriela O. Paiva-Silva,David Majerowicz,Marcelo Medeiros,Leonardo Koerich,Walter R. Terra,Clélia Ferreira,André C. Pimentel,Paulo M. Bisch,Daniel C. Leite,Michelle M. P. Diniz,Jo?o Lídio da S. G. V. Junior,Manuela L. Da Silva,Ricardo N. Araujo,Ana Caroline P. Gandara,Sébastien Brosson,Didier Salmon,Sabrina Bousbata,Natalia González-Caballero,Ariel Mariano Silber,Michele Alves-Bezerra,Katia C. Gondim,Mário Alberto C. Silva-Neto,Georgia C. Atella,Helena Araujo,Felipe A. Dias,Carla Polycarpo,Raquel J. Vionette-Amaral,Patrícia Fampa,Ana Claudia A. Melo,Aparecida S. Tanaka,Carsten Balczun,José Henrique M. Oliveira,Renata L. S. Gon?alves,Cristiano Lazoski,Rolando Rivera-Pomar,Luis Diambra,Günter A. Schaub,Elói S. Garcia,Patrícia Azambuja,Glória R. C. Braz ,Pedro L. Oliveira
PLOS Neglected Tropical Diseases , 2014, DOI: 10.1371/journal.pntd.0002594
Abstract: The bloodsucking hemipteran Rhodnius prolixus is a vector of Chagas' disease, which affects 7–8 million people today in Latin America. In contrast to other hematophagous insects, the triatomine gut is compartmentalized into three segments that perform different functions during blood digestion. Here we report analysis of transcriptomes for each of the segments using pyrosequencing technology. Comparison of transcript frequency in digestive libraries with a whole-body library was used to evaluate expression levels. All classes of digestive enzymes were highly expressed, with a predominance of cysteine and aspartic proteinases, the latter showing a significant expansion through gene duplication. Although no protein digestion is known to occur in the anterior midgut (AM), protease transcripts were found, suggesting secretion as pro-enzymes, being possibly activated in the posterior midgut (PM). As expected, genes related to cytoskeleton, protein synthesis apparatus, protein traffic, and secretion were abundantly transcribed. Despite the absence of a chitinous peritrophic membrane in hemipterans - which have instead a lipidic perimicrovillar membrane lining over midgut epithelia - several gut-specific peritrophin transcripts were found, suggesting that these proteins perform functions other than being a structural component of the peritrophic membrane. Among immunity-related transcripts, while lysozymes and lectins were the most highly expressed, several genes belonging to the Toll pathway - found at low levels in the gut of most insects - were identified, contrasting with a low abundance of transcripts from IMD and STAT pathways. Analysis of transcripts related to lipid metabolism indicates that lipids play multiple roles, being a major energy source, a substrate for perimicrovillar membrane formation, and a source for hydrocarbons possibly to produce the wax layer of the hindgut. Transcripts related to amino acid metabolism showed an unanticipated priority for degradation of tyrosine, phenylalanine, and tryptophan. Analysis of transcripts related to signaling pathways suggested a role for MAP kinases, GTPases, and LKBP1/AMP kinases related to control of cell shape and polarity, possibly in connection with regulation of cell survival, response of pathogens and nutrients. Together, our findings present a new view of the triatomine digestive apparatus and will help us understand trypanosome interaction and allow insights into hemipteran metabolic adaptations to a blood-based diet.
CK2 Phosphorylation of Schistosoma mansoni HMGB1 Protein Regulates Its Cellular Traffic and Secretion but Not Its DNA Transactions
Isabel Caetano de Abreu da Silva, Vitor Coutinho Carneiro, Renata de Moraes Maciel, Rodrigo Furtado Madeiro da Costa, Daniel Rodrigues Furtado, Francisco Meirelles Bastos de Oliveira, Mário Alberto Cardoso da Silva-Neto, Franklin David Rumjanek, Marcelo Rosado Fantappié
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0023572
Abstract: Background The helminth Schistosoma mansoni parasite resides in mesenteric veins where fecundated female worms lay hundred of eggs daily. Some of the egg antigens are trapped in the liver and induce a vigorous granulomatous response. High Mobility Group Box 1 (HMGB1), a nuclear factor, can also be secreted and act as a cytokine. Schistosome HMGB1 (SmHMGB1) is secreted by the eggs and stimulate the production of key cytokines involved in the pathology of schistosomiasis. Thus, understanding the mechanism of SmHMGB1 release becomes mandatory. Here, we addressed the question of how the nuclear SmHMGB1 can reach the extracellular space. Principal Findings We showed in vitro and in vivo that CK2 phosphorylation was involved in the nucleocytoplasmic shuttling of SmHMGB1. By site-directed mutagenesis we mapped the two serine residues of SmHMGB1 that were phosphorylated by CK2. By DNA bending and supercoiling assays we showed that CK2 phosphorylation of SmHMGB1 had no effect in the DNA binding activities of the protein. We showed by electron microscopy, as well as by cell transfection and fluorescence microscopy that SmHMGB1 was present in the nucleus and cytoplasm of adult schistosomes and mammalian cells. In addition, we showed that treatments of the cells with either a phosphatase or a CK2 inhibitor were able to enhance or block, respectively, the cellular traffic of SmHMGB1. Importantly, we showed by confocal microscopy and biochemically that SmHMGB1 is significantly secreted by S. mansoni eggs of infected animals and that SmHMGB1 that were localized in the periovular schistosomotic granuloma were phosphorylated. Conclusions We showed that secretion of SmHMGB1 is regulated by phosphorylation. Moreover, our results suggest that egg-secreted SmHMGB1 may represent a new egg antigen. Therefore, the identification of drugs that specifically target phosphorylation of SmHMGB1 might block its secretion and interfere with the pathogenesis of schistosomiasis.
Micro-leakage at the implant-abutment interface with different tightening torques in vitro
Silva-Neto, Jo?o Paulo da;Prudente, Marcel Santana;Carneiro, Thiago de Almeida Prado Naves;Nóbilo, Mauro Ant?nio de Arruda;Penatti, Mario Paulo Amante;Neves, Flávio Domingues das;
Journal of Applied Oral Science , 2012, DOI: 10.1590/S1678-77572012000500015
Abstract: objectives: this study evaluated the microleakage at the implant/abutment interface of external hexagon (eh) implants and abutments with different amounts of bacteria and tightening torques. material and methods: a bacterial suspension was prepared to inoculate the implants. the first phase of this study used nine eh implants and abutments that were divided into three groups with different amounts of bacterial suspension (n=3): v0.5: 0.5 μl; v1.0: 1.0 μl e v1.5: 1.5 μl, and tightened to the manufacturer's recommended torque. the second phase of this experiment used 27 assemblies that were similar to those used in the first phase. these samples were inoculated with 0.5 μl of bacterial suspension and divided into three groups (n=9). t10: 10 ncm; t20: 20 ncm and t32: 32 ncm. the samples were evaluated according to the turbidity of the broth every 24 hours for 14 days, and the bacteria viability was tested after that period. the statistical evaluation was conducted by kruskal-wallis testing (p<.05). results: during the first phase, groups v1.0 and v1.5 was presented with bacterial contamination in all samples after 24 h. during the second phase, two samples from group t10 and one from t20 presented positive results for bacterial contamination. different amounts of bacterial solution led to overflow and contamination during the first 24 h of the experiment. the tightening torques did not statistically affect the microleakage in the assemblies. however, the group that was tightened to 32 ncm torque did not show any bacterial contamination. conclusion: after 14 days of experimentation, the bacteria were proven to remain viable inside the implant internal cavity.
Ethanol Intake during Lactation Alters Milk Nutrient Composition and Growth and Mineral Status of Rat Pups
AZARA,CíNTIA R.P; MAIA,INGRID C; RANGEL,CAROLINA N; SILVA-NETO,MáRIO A.C; SERPA,RENATA F.B; DE JESUS,EDGAR F.O; TAVARES ?DO CARMO,MARIA G; FIALHO,ELIANE;
Biological Research , 2008, DOI: 10.4067/S0716-97602008000300008
Abstract: lactating wistar rats were fed a liquid diet containing either ethanol [ethanol-fed group (efg)] or an isocaloric amount of carbohydrate [pair-fed group (pfg)] from day 1 postpartum up to day 14 of lactation, to investigate micro/macronutrient milk composition and the mineral status of pups. efg presented a reduction of daily milk production and milk composition was significantly higher in protein and lower in carbohydrate, while the lipid content was similar to that of pfg. when compared to pfg, the milk of efg had a decreased proportion of c22:6 n-3 fatty acid and an increase in medium-chain fatty acids and of several minerals. pups of efg showed reduced growth and a lower concentration of cu and sr in plasma and lower concentrations of ca, p and cl, and higher concentrations of cd in the brain. we conclude that maternal etoh intake greatly impairs lactational performance and modifies the mineral status of pups.
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