Alpha-glucosidase promotes hemozoin formation in a blood-sucking bug: An evolutionary history

Background: Hematophagous insects digest large amounts of host hemoglobin and release heme inside their guts. In Rhodnius prolixus, hemoglobin-derived heme is detoxified by biomineralization, forming hemozoin (Hz). Recently, the involvement of the R. prolixus perimicrovillar membranes in Hz formation was demonstrated. Methodology/Principal Findings: Hz formation activity of an α-glucosidase was investigated. Hz formation was inhibited by specific α-glucosidase inhibitors. Moreover, Hz formation was sensitive to inhibition by Diethypyrocarbonate, suggesting a critical role of histidine residues in enzyme activity. Additionally, a polyclonal antibody raised against a phytophagous insect α-glucosidase was able to inhibit Hz formation. The α-glucosidase inhibitors have had no effects when used 10 h after the start of reaction, suggesting that α-glucosidase should act in the nucleation step of Hz formation. Hz formation was seen to be dependent on the substrate-binding site of enzyme, in a way that maltose, an enzyme substrate, blocks such activity. dsRNA, constructed using the sequence of α-glucosidase gene, was injected into R. prolixus females' hemocoel. Gene silencing was accomplished by reduction of both α-glucosidase and Hz formation activities. Insects were fed on plasma or hemin-enriched plasma and gene expression and activity of α-glucosidase were higher in the plasma plus hemin-fed insects. The deduced amino acid sequence of α-glucosidase shows a high similarity to the insect α-glucosidases, with critical histidine and aspartic residues conserved among the enzymes. Conclusions/Significance: Herein the Hz formation is shown to be associated to an a-glucosidase, the biochemical marker from Hemipteran perimicrovillar membranes. Usually, these enzymes catalyze the hydrolysis of glycosidic bond. The results strongly suggest that α-glucosidase is responsible for Hz nucleation in the R. prolixus midgut, indicating that the plasticity of this enzyme may play an important role in conferring fitness to hemipteran hematophagy, for instance. © 2009 Mury et al.

Morphologic changes and the expression of alpha-melanocyte stimulating hormone and melanocortin-1 receptor in melasma lesions: A comparative study

Melasma is a common acquired symmetrical hypermelanosis characterized by irregular light- to dark-brown macules on sun-exposed skin areas. The literature shows few studies on its physiopathogeny. However, changes in α-melanocyte stimulating hormone (α-MSH) secretion and melanocortin-1 receptor (MC1-R) expression may play a role to trigger this condition. Biopsies were taken from both melasma skin and adjacent perilesional normal skin of 44 patients. The biopsies were submitted for hematoxylin and eosin and Fontana-Masson staining and immunohistochemistry with Melan-A, α-MSH, and MC1-R, and processed for transmission electron microscopy. In some cases, they were submitted to MC1-R gene expression analysis by real-time polymerase chain reaction. Increased lymphohistiocytic infiltrate and solar elastosis, higher epidermal melanin were observed in melasma skin. Electron microscopy revealed a greater number of mature melanosomes in keratinocytes and melanocytes, and more prominent cytoplasmic organelles in melasma skin. There was no difference in melanocyte number between areas. However, melanocytes were larger and more dendritic in melasma skin. Immunohistochemistry with α-MSH and MC1-R showed significant labeling in melasmic epidermis but MC1-R messenger ribonucleic acid (RNAm) did not show significant quantitative difference between melasma and normal skin. © 2010 by Lippincott Williams & Wilkins.

Fluazuron-induced morphophysiological changes in the cuticle formation and midgut of Rhipicephalus sanguineus Latreille, 1806 (Acari: Ixodidae) nymphs

The present study demonstrated the effects of the arthropod growth regulator, fluazuron (Acatak®), in the formation of the integument and digestive processes of Rhipicephalus sanguineus nymphs fed on rabbits treated with different doses of this chemical acaricide. For this, three different doses of fluazuron (20, 40, or 80 mg/kg) were applied pour on to the hosts (groups II, III, and IV), as well as distilled water to the control group. On the first day after treatment (24 h), the hosts were artificially infested with R. sanguineus nymphs. After full engorgement (7 days), the nymphs were removed, placed on labeled Petri dishes, and kept in biochemical oxygen demand incubator for 7 days. The engorged nymphs were then taken for morphological, histochemical, and histological analyses. The results showed the occurrence of cytological, morphohistological, and histochemical alterations in the integument and midgut of nymphs from all the different treated groups. These alterations occurred at cuticular level in the subdivisions of the cuticle, related to the size of the digestive cells, amount of accumulated blood elements, and digestive residues, as well as the presence of vacuoles in the cytoplasm of the digestive cells. Thus, this study demonstrated that fluazuron acts on the integument and midgut cells of R. sanguineus nymphs fed on treated rabbits and pointed out the possibility of the use of this chemical - which is more specific, less toxic, and less harmful to the environment and nontarget organisms - in the control of R. sanguineus, at least in the nymphal stage of its biological cycle. © 2012 Springer-Verlag.

Influence of gasoline inhalation on the enantioselective pharmacokinetics of fluoxetine in rats

Fluoxetine is used clinically as a racemic mixture of (+)-(S) and (-)-(R) enantiomers for the treatment of depression. CYP2D6 catalyzes the metabolism of both fluoxetine enantiomers. We aimed to evaluate whether exposure to gasoline results in CYP2D inhibition. Male Wistar rats exposed to filtered air (n = 36; control group) or to 600 ppm of gasoline (n = 36) in a nose-only inhalation exposure chamber for 6 weeks (6 h/day, 5 days/week) received a single oral 10-mg/kg dose of racemic fluoxetine. Fluoxetine enantiomers in plasma samples were analyzed by a validated analytical method using LC-MS/MS. The separation of fluoxetine enantiomers was performed in a Chirobiotic V column using as the mobile phase a mixture of ethanol:ammonium acetate 15 mM. Higher plasma concentrations of the (+)-(S)-fluoxetine enantiomer were found in the control group (enantiomeric ratio AUC(+)-(S)/(-)-(R) = 1.68). In animals exposed to gasoline, we observed an increase in AUC0-∞ for both enantiomers, with a sharper increase seen for the (-)-(R)-fluoxetine enantiomer (enantiomeric ratio AUC(+)-(S)/(-)-(R) = 1.07), resulting in a loss of enantioselectivity. Exposure to gasoline was found to result in the loss of enantioselectivity of fluoxetine, with the predominant reduction occurring in the clearance of the (-)-(R)-fluoxetine enantiomer (55% vs. 30%). Chirality 25:206-210, 2013. © 2013 Wiley Periodicals, Inc. Copyright © 2013 Wiley Periodicals, Inc.

Gender differences in Internet use

Includes bibliography

Early larval development in the laboratory of Alpheus estuariensis (Crustacea: Caridea) from the Amazon Region

O presente estudo descreve e ilustra em detalhes os quatro primeiros estágios de Alpheus estuariensis Christoffersen, 1984 a partir de larvas cultivadas em laboratório. Duas fêmeas ovígeras foram coletadas no canal de maré do estuário de Bragança, estado do Pará, nordeste do Brasil. Após a eclosão, as larvas foram colocadas em pequenos recipientes (com 10 larvas em cada). As fêmeas foram depositadas no Museu Paraense Emilio Goeldi (MPEG 0803) e as larvas de cada estágio larval no Museu zoológico da Universidade de São Paulo (MUSP18452). Foram dissecadas 10 larvas e exúvias com finas agulhas sob um microscópio ocular. Comparações morfológicas com outros estudos reportados sobre o desenvolvimento larval de espécies de Alpheus são brevemente discutidas.

Cuidados parentais e trajetórias de desenvolvimento: um estudo observacional de díades mãe-bebê de dois níveis socioeconômicos de Belém, Brasil

Este estudo utilizou como referencia teórico o Modelo de Investimento Parental proposto por Heidi Keller, que indica seis sistemas parentais – cuidados primários, contato corporal, estimulação corporal, estimulação por objeto, troca face-a-face e envelope narrativo – e três mecanismos de interação – atenção, contingência e calor emocional, os quais são independentes entre si e a predominância de um ou outro dependerá da cultura e de características socioeconômicas. Os objetivos desse trabalho foram caracterizar o investimento parental de díades mãe-bebê pertencentes às classes socioeconômicas baixa (CEB) e média (CEM) da cidade de Belém e o estilo conversacional utilizado nas emissões verbais das mães quando em interação verbal com seus bebês. Participaram 20 mães, sendo nove da CEB e 11 da CEM. A média da idade das mães da CEB foi 24,5, a maioria tinha o nível de escolaridade fundamental (77,8%) e médio (22,2%), completos ou não, apresentaram renda mensal inferior que as mães do outro grupo e residiam em áreas periféricas. Quanto a CEM, a média da idade das mães foi 30,7, e a maioria tinha nível educacional superior (63,3%) e residiam no centro da cidade. Foram observadas e gravadas as interações mãe-bebê em sessões de banho e troca, na casa da díade, para posterior análise e transcrição do comportamento verbal com o aplicativo Transana 2.41. Os resultados indicaram que as mães da CEB priorizaram as práticas parentais que valorizam a interdependência durante suas interações, embora também tenham apresentado práticas distais, porém com menor frequência. As mães da CEM, apresentaram práticas parentais que valorizam tanto a autonomia quanto a relacionalidade. Quanto aos mecanismos de interação, observou-se que as mães de ambos os grupos foram mais contingentes aos sinais positivos do que aos negativos do bebê, característica própria de sociedades que priorizam a independência e autonomia do sujeito; e evidenciaram mais calor emocional ao responder aos sinais positivos em comparação com os negativos. Em relação ao estilo conversacional, as mães de CEB utilizaram com maior frequência o estilo diretivo, e as mães de CEM, utilizaram os dois estilos com freqências muito próximas. Os resultados deste estudo sugerem um perfil interdependente para o grupo CEB e um perfil autônomo-relacionado para a amostra de mães urbanas de classe média.

Acute toxicity and histopathology in ornamental fish amazon bluespotted corydora (Corydoras melanistius) exposed to formalin

O objetivo do trabalho foi determinar a toxicidade aguda de formalina e os efeitos histopatológicos para o peixe ornamental amazônico corredora bicuda (Corydora melanistius). Foi utilizado um delineamento inteiramente casualizado; com dez concentrações de formalina 40% (0, 3, 6, 12, 25, 50, 100, 150, 200 e 250mg.L^-1), com quatro repetições e cinco peixes por recipiente de água (3 L) em sistema estático durante 96 horas. Os peixes moribundos foram mortos e fixados em formol 10% procedendo à análise histopatológica das brânquias e do fígado. Ao final desse experimento, obtiveram-se as seguintes taxas de mortalidades em ordem crescente de exposição (%): 0, 0, 0, 0, 0, 65, 85, 100, 100 e 100. A concentração letal 50% (CL inicial (I)50-96h) foi estimada em 50, 76 mg/L com a seguinte equação de regressão y = 0, 51x com r² = 0, 80. Pode observar nas concentrações mais elevadas, alterações como hiperplasia branquial e fusão lamelar, enquanto que no fígado foi observado desorganização do arranjo cordonal, assim como necrose no rim. Com isso no presente estudo, a formalina pode ser considerada pouco tóxica para a corredora bicuda, mas causa alterações morfológicas acentuadas quando expostas a concentrações elevadas. Dessa forma o uso de formalina no próprio rio de coleta dos peixes com a utilização de dosagens erradas pode causar impactos ambientais e biológicos negativos.

Fluazuron-induced morphological changes in Rhipicephalus sanguineus Latreille, 1806 (Acari: Ixodidae) nymphs: An ultra-structural evaluation of the cuticle formation and digestive processes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A construção dos saberes docentes: um olhar sobre as experiências de professores da disciplina de História acerca da temática de diversidade sexual

Pós-graduação em Educação Escolar - FCLAR

Lysine in the diet of Rhamdia voulezi male broodstocks confined in net cages

The focus of this study was to evaluate the effect of lysine on the productive (weight and length gain, apparent feed conversion, specific growth rate and condition factor) and reproductive performance of Rhamdia voulezi males confined in net cages during the first reproductive cycle. The following parameters were assessed: seminal parameters (motility rate and duration, survival, sperm concentration, morphology, pH and osmolarity), hormonal parameters (cortisol and testosterone), testicular tissue (histomorphology), organosomatic indices (gonadosomatic, hepatosomatic and viscerosomatic indices) and composition of essential amino acids, crude protein and moisture of whole carcass. Four hundred fish were used, distributed in a random experimental design with four treatments and four replications in 16 net cages with 25 fish each. The treatments consisted of four different diets prepared so as to contain the following levels of lysine: 1.20, 1.40, 1.60 and 1.80%, with 30% crude protein and 3500 kcal kg(-1) digestible energy for 185 days (Jul./12-Jan./13). Eighteen males were selected per treatment, and they all released semen after slight abdominal pressure. The males were weighed, measured, submitted to hypophysation (2.5 mg kg(-1) carp pituitary extract), and then had their semen and blood collected. The fish were sacrificed by cervical dislocation, dissected, and the testes, liver, fat and guts were removed and weighed. The effects (p < 0.05) for the means of final weight, weight gain, apparent feed conversion and condition factor were observed for the analysis of productive performance. With regard to the reproductive parameters, only the seminal volume was affected (p < 0.05). Thus, the levels of testosterone showed quadratic effect (p < 0.05). The anatomy and the histomorphology of the testes were similar between the treatments during the spermiation period. With regard to the organosomatic indices, there was no influence (p > 0.05) between the treatments. The amino acids in the carcass were not affected (p > 0.05). The increment of lysine in the diet provided linear increase for weight gain and seminal volume and linear decrease for feed conversion in R. voulezi broodstocks confined in net cages. (C) 2014 Elsevier B.V. All rights reserved.

Influence of Fc gamma RIIIb polymorphism on its ability to cooperate with Fc gamma RIIa and CR3 in mediating the oxidative burst of human neutrophils

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

EFFECTS OF EMERGENCY IN BIOSTIMULANT SEEDLING OF PASSION FRUIT ROXINHO OF KENYA

The increase in market demand for fresh fruits along with the high price of passion fruit juice in domestic and international markets has increased the interest in fruit, especially the purple passion fruit in the center south of the country seeking to export. This study aimed to evaluate the effects of plant growth regulator on the emergence and development of seedlings of passion 'Roxinho of Kenya' when propagated sexually. The treatments consisted of concentrations of commercial product Stimulate (R): control (no biostimulant); 6; 12; 18; 24 and 30 mL. kg(-1) of seed. It were evaluated the percentage of seedling emergence, number of leaves, aerial part dry weight, stem and root (g), root length (mm), diameter and stem length (mm), leaf area and chlorophyll 'a' and 'b'. The application of bio-stimulant in doses of 6 and 12 mL. kg(-1) promotes increased percentage of seedling emergence of Passiflora edulis Sims in a shorter time. The use of it also promotes the development of seedlings, with better results for the dose of 12 and 24 mL. kg(-1) treated seeds.

Analise do sistema de medição em peças aeronaúticas através do estudo de R&R (repetibilidade e reprodutibilidade)

The Measurement System Analysis (MSA - Measurement System Analysis) is a statistical methodology developed to study and analyze the behavior of the measurement systems, and, therefore, allow the increased of the confidence readings performed by measuring instruments. It’s widely used in the automotive industry since the 90’s and is a mandatory requirement for the approval of the parts according to ISO Standard of the automotive sector. However, the aerospace industry doesn’t require this type of Study, once which the vast majority of aeronautics parts have characteristics (dimensions) with very tight tolerances, closed, ie, at the home of microns. This work aims to create lists of recommendations for definitions of measuring instruments in developing of control plans, which correlates tolerances fields of characteristics for different settings and acceptance of the instrument, classified as optimum, recommended and not recommended, through of the study of R&R (Repeatability and Reproducibility) in aeronautics parts. Every methodology of the experimental part was based on modern strategy of continuous improvement, the DMAIC (Define Measure Analyze Implant Control), in order to achieve better measurement method used in the control of milling aeronautics parts, identifying and reducing the variations of the measurement process. The results of the R&R Study in large part of measuring instrument manuals were considered acceptable and/or recommended, ie with values of %P/T and %RR lower than 30%, providing statistical data which have enabled the elaboration of tables of recommendations, which, from this work, have turned into very important documents and aid for Process Engineering, having in their hands a technical study able to identify which is the most appropriate instrument to get a more robust dimensional... (Complete abstract click electronic access below)