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Search Results: 1 - 10 of 281819 matches for " Marcos H. F. Sorgine "
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Blood-Feeding Induces Reversible Functional Changes in Flight Muscle Mitochondria of Aedes aegypti Mosquito
Renata L. S. Gon?alves,Ana Carolina L. Machado,Gabriela O. Paiva-Silva,Marcos H. F. Sorgine,Marisa M. Momoli,Jose Henrique M. Oliveira,Marcos A. Vannier-Santos,Antonio Galina,Pedro L. Oliveira,Marcus F. Oliveira
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0007854
Abstract: Hematophagy poses a challenge to blood-feeding organisms since products of blood digestion can exert cellular deleterious effects. Mitochondria perform multiple roles in cell biology acting as the site of aerobic energy-transducing pathways, and also an important source of reactive oxygen species (ROS), modulating redox metabolism. Therefore, regulation of mitochondrial function should be relevant for hematophagous arthropods. Here, we investigated the effects of blood-feeding on flight muscle (FM) mitochondria from the mosquito Aedes aegypti, a vector of dengue and yellow fever.
Dengue Infection Increases the Locomotor Activity of Aedes aegypti Females
Tamara N. Lima-Camara,Rafaela V. Bruno,Paula M. Luz,Márcia G. Castro,Ricardo Louren?o-de-Oliveira,Marcos H. F. Sorgine,Alexandre A. Peixoto
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0017690
Abstract: Aedes aegypti is the main vector of the virus causing Dengue fever, a disease that has increased dramatically in importance in recent decades, affecting many tropical and sub-tropical areas of the globe. It is known that viruses and other parasites can potentially alter vector behavior. We investigated whether infection with Dengue virus modifies the behavior of Aedes aegypti females with respect to their activity level.
Blood Meal-Derived Heme Decreases ROS Levels in the Midgut of Aedes aegypti and Allows Proliferation of Intestinal Microbiota
Jose Henrique M. Oliveira,Renata L. S. Gon?alves,Flavio A. Lara,Felipe A. Dias,Ana Caroline P. Gandara,Rubem F. S. Menna-Barreto,Meredith C. Edwards,Francisco R. M. Laurindo,Mário A. C. Silva-Neto,Marcos H. F. Sorgine,Pedro L. Oliveira
PLOS Pathogens , 2011, DOI: 10.1371/journal.ppat.1001320
Abstract: The presence of bacteria in the midgut of mosquitoes antagonizes infectious agents, such as Dengue and Plasmodium, acting as a negative factor in the vectorial competence of the mosquito. Therefore, knowledge of the molecular mechanisms involved in the control of midgut microbiota could help in the development of new tools to reduce transmission. We hypothesized that toxic reactive oxygen species (ROS) generated by epithelial cells control bacterial growth in the midgut of Aedes aegypti, the vector of Yellow fever and Dengue viruses. We show that ROS are continuously present in the midgut of sugar-fed (SF) mosquitoes and a blood-meal immediately decreased ROS through a mechanism involving heme-mediated activation of PKC. This event occurred in parallel with an expansion of gut bacteria. Treatment of sugar-fed mosquitoes with increased concentrations of heme led to a dose dependent decrease in ROS levels and a consequent increase in midgut endogenous bacteria. In addition, gene silencing of dual oxidase (Duox) reduced ROS levels and also increased gut flora. Using a model of bacterial oral infection in the gut, we show that the absence of ROS resulted in decreased mosquito resistance to infection, increased midgut epithelial damage, transcriptional modulation of immune-related genes and mortality. As heme is a pro-oxidant molecule released in large amounts upon hemoglobin degradation, oxidative killing of bacteria in the gut would represent a burden to the insect, thereby creating an extra oxidative challenge to the mosquito. We propose that a controlled decrease in ROS levels in the midgut of Aedes aegypti is an adaptation to compensate for the ingestion of heme.
Heme-Oxygenases during Erythropoiesis in K562 and Human Bone Marrow Cells
Liliane R. Alves, Elaine S. Costa, Marcos H. F. Sorgine, Maria Clara L. Nascimento-Silva, Cristina Teodosio, Paloma Bárcena, Hugo C. Castro-Faria-Neto, Patrícia T. Bozza, Alberto Orfao, Pedro L. Oliveira, Clarissa M. Maya-Monteiro
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0021358
Abstract: In mammalian cells, heme can be degraded by heme-oxygenases (HO). Heme-oxygenase 1 (HO-1) is known to be the heme inducible isoform, whereas heme-oxygenase 2 (HO-2) is the constitutive enzyme. Here we investigated the presence of HO during erythroid differentiation in human bone marrow erythroid precursors and K562 cells. HO-1 mRNA and protein expression levels were below limits of detection in K562 cells. Moreover, heme was unable to induce HO-1, at the protein and mRNA profiles. Surprisingly, HO-2 expression was inhibited upon incubation with heme. To evaluate the physiological relevance of these findings, we analyzed HO expression during normal erythropoiesis in human bone marrow. Erythroid precursors were characterized by lack of significant expression of HO-1 and by progressive reduction of HO-2 during differentiation. FLVCR expression, a recently described heme exporter found in erythroid precursors, was also analyzed. Interestingly, the disruption in the HO detoxification system was accompanied by a transient induction of FLVCR. It will be interesting to verify if the inhibition of HO expression, that we found, is preventing a futile cycle of concomitant heme synthesis and catabolism. We believe that a significant feature of erythropoiesis could be the replacement of heme breakdown by heme exportation, as a mechanism to prevent heme toxicity.
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.
Validation of Aedes aegypti Aag-2 cells as a model for insect immune studies
Barletta Ana,Silva Maria Clara L Nascimento,Sorgine Marcos
Parasites & Vectors , 2012, DOI: 10.1186/1756-3305-5-148
Abstract: Background The understanding of mosquito immune responses can provide valuable tools for development of novel mosquito control strategies. Aiming the study at insect innate immunity, continuous insect cell lines have been established and used as research tools due to the fact that they constitute more homogeneous, sensitive, and reproducible systems than the insects from which they originated. More recently, Aag-2, an Aedes aegypti cell lineage, began to be frequently used as a model for studies of mosquito immunity. Nevertheless, to our knowledge, no study has systematically characterized the responses of Aag-2 cell line against different kinds of pathogens and compared its response to those exhibited by whole mosquitoes. For this reason, in this study we characterized gene expression profiles of the Aag-2 cell line in response to different kinds of immune challenges, such as Gram negative and positive bacteria, fungi and viruses, comparing the obtained results with the ones already described in the literature for whole mosquitoes. Methods Aedes aegypti Aag-2 cells were exposed to different immune stimuli (gram-positive and gram negative heat inactivated bacteria, zymosan or Sindbis virus) for 24 hours and the expression of selected marker genes from toll, IMD and Jak/STAT pathways was analyzed by qPCR. Also, cells were incubated with fluorescent latex beads for evaluation of its phagocytosis capacity. Results Aag-2 cells were stimulated with two concentrations of heat-killed Gram negative (Enterobacter cloacae) or Gram positive (Micrococcus luteus) bacteria, Zymosan or infected with Sindbis virus and the expression of key genes from the main immune related pathways, Toll, IMD and Jak/STAT, were investigated. Our results suggest that Toll and IMD pathways are activated in response to both Gram positive and negative bacteria and Zymosan in Aag-2 cells, displaying an immune profile similar to those described in the literature for whole mosquitoes. The same stimuli were also capable of activating Jak/STAT pathway in Aag-2 cells. Infection with Sindbis virus led to an up-regulation of the transcription factor STAT but was not able to induce the expression of any other gene from any of the pathways assayed. We also showed that this cell line is able to phagocytose latex beads in culture. Conclusions Our results characterize the expression profile of Aag-2 cells in response to different immune stimuli and demonstrate that this cell lineage is immune-competent and closely resembles the response described for whole Ae. aegypti mosquitoes. Hence, our f
Morphology and Thermal Properties of Core-Shell PVA/PLA Ultrafine Fibers Produced by Coaxial Electrospinning  [PDF]
Raquel P. Gon?alves, Flavia F. F. da Silva, Paulo H. S. Picciani, Marcos L. Dias
Materials Sciences and Applications (MSA) , 2015, DOI: 10.4236/msa.2015.62022
Abstract: Coaxial electrospinning process was used to produce biodegradable membranes made of coreshell fibers of a poly(lactic acid) (PLA) shell and a poly(vinyl alcohol) (PVA) core. Scanning electron microscopy analyses of these structures showed that the PLA shell can present certain porosity depending on the process condition. FTIR-ATR and contact angle measurements also suggested imprisonment of the PVA core within the PLA shell. This type of structure was also confirmed by means of transmissions electron microscopy. The morphology of these fibers was dependent on the flow rate of both core and shell solutions, and homogeneous and smooth surface was only attained when the flow rate of the external PLA solution was 4 times the flow rate of the internal PVA solution. The increase in the PLA solution flow rate increases the diameter of the core-shell fiber which reaches up to 1.7 μm. Nevertheless, fibers with smaller average diameter could also be produced (200 nm). These core-shell fibers presented improved hydrophilicity as compared with monolithic PLA fibers.
SELECTIVE ACTIVATION OF THE RECTUS ABDOMINIS MUSCLE DURING LOW-INTENSITY AND FATIGUING TASKS
Paulo H. Marchetti,André F. Kohn,Marcos Duarte
Journal of Sports Science and Medicine , 2011,
Abstract: In order to understand the potential selective activation of the rectus abdominis muscle, we conducted two experiments. In the first, subjects performed two controlled isometric exercises: the curl up (supine trunk raise) and the leg raise (supine bent leg raise) at low intensity (in which only a few motor units are recruited). In the second experiment, subjects performed the same exercises, but they were required to maintain a certain force level in order to induce fatigue. We recorded the electromyographic (EMG) activities of the lower and upper portions of the rectus abdominis muscle during the exercises and used spatial-temporal and frequency analyses to describe muscle activation patterns. At low-intensity contractions, the ratio between the EMG intensities of the upper and lower portions during the curl up exercise was significantly larger than during the leg raise exercise (p = 0.02). A cross-correlation analysis indicated that the signals of the abdominal portions were related to each other and this relation did not differ between the tasks (p = 0.12). In the fatiguing condition, fatigue for the upper portion was higher than for the lower portion during the curl up exercise (p = 0.008). We conclude that different exercises evoked, to a certain degree, individualized activation of each part of the rectus abdominis muscle, but different portions of the rectus abdominis muscle contributed to the same task, acting like a functional unit. These results corroborate the relevance of varying exercise to modify activation patterns of the rectus abdominis muscle
Purification and Preliminary Crystallographic Analysis of a New Lys49-PLA2 from B. Jararacussu
Marcelo L. dos Santos,F????bio H. R. Fagundes,Bruno R. F. Teixeira,Marcos H. Toyama
International Journal of Molecular Sciences , 2008,
Abstract: BjVIII is a new myotoxic Lys49-PLA2 isolated from Bothrops jararacussu venom that exhibits atypical effects on human platelet aggregation. To better understand the mode of action of BjVIII, crystallographic studies were initiated. Two crystal forms were obtained, both containing two molecules in the asymmetric unit (ASU). Synchrotron radiation diffraction data were collected to 2.0 °A resolution and 1.9 °A resolution for crystals belonging to the space group P212121 (a = 48:4 A ° , b = 65:3 A ° , c = 84:3 A ° ) and space group P3121 (a = b = 55:7 A ° , c = 127:9 A ° ), respectively. Refinement is currently in progress and the refined structures are expected to shed light on the unusual platelet aggregation activity observed for BjVIII.
Primary culture of Rhodnius prolixus (Hemiptera: Reduviidae) salivary gland cells
Rocha, Fernanda F;Araujo, Ricardo N;Silva, Luciana M;Gontijo, Nelder F;Pereira, Marcos H;
Memórias do Instituto Oswaldo Cruz , 2010, DOI: 10.1590/S0074-02762010000200004
Abstract: in the present paper, we developed a primary culture of rhodnius prolixus salivary gland and main salivary canal cells. cells remained viable in culture for 30 days. three types of cells were indentified in the salivary gland cultures, with binuclear cells being the most abundant. the supernatants of salivary cultures contained mainly 16-24 kda proteins and presented anticoagulant and apyrase activities. secretion vesicles were observed budding from the cellular monolayer of the main salivary canal cells. these results indicate that r. prolixus salivary proteins may be produced in vitro and suggest that the main salivary canal may have a possible secretory role.
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