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911.
Ana Claudia Henriques Pinto Antonio Marcos A. Levy Carla Domingues Santos 《Experimental parasitology》2010,124(2):147-152
The incidence and progression of disorders associated with an unbalanced immune response has among many factors the gender as a contributory factor. The aims of this work were to evaluate the effects of orchiectomy and the immune response during the experimental Trypanosoma cruzi infection. Young adult, male Calomys callous were i.p. inoculated with 1 × 105 blood trypomastigotes of the CM strain of T. cruzi and divided in groups: Control, Sham and Castrated. Castrated group displayed significantly lower values for prostate and seminal vesicle weights indicating a drastic drop of testosterone plasmatic levels. Orchiectomized animals also displayed lesser number of blood parasites, enhanced lytic antibody percentage, splenocyte proliferation and NO concentration when compared to its sham and control counterparts, indicating that steroid gonadal ablation actually influences immune response triggering a more efficient cellular and humoral response which led animals to become more resistant against T. cruzi infection. 相似文献
912.
Luana Pereira Antunes Dourado Daniela Longo Gargiulo Cláudia Caldeira Brant Raphaela Mendes Fernandes de Souza Danielle da Glória de Souza 《Cellular immunology》2010,262(1):62-68
To ascertain the role of IL-4 in aversion to antigen induced by food allergy, wild type and IL-4 deficient BALB/c mice were sensitized with ovalbumin and challenged orally with egg white. Sensitized wild type mice had increased production of IL-4 by spleen and mesenteric lymph node cells in vitro, higher levels of serum anti-ovalbumin IgE and IgG1, aversion to ingestion of the antigen and loss of body weight after continuous oral challenge. Intestinal changes in wild type sensitized mice included eosinophil infiltration and increased mucus production. The IL-4 deficiency impaired the development of food allergy and the aversion to antigen, suggesting the involvement of the antigen specific antibodies. When IL-4 deficient mice received serum from sensitized wild type donors, the aversion was restored. These results indicate that production of IL-4 and specific IgE/IgG1 antibodies correlate with aversion to antigen induced by food allergy in mice. 相似文献
913.
Batrachochytrium dendrobatidis (Bd), a disease-causing amphibian-specific fungus, is widely distributed in Puerto Rico, but is restricted to elevations above 600 m. The effect of this pathogen in the wild was studied by monitoring Eleutherodactylus coqui and E. portoricensis in 2 upland forests at El Yunque, a site characterized by historic population declines in the presence of chytridiomycosis. We tested a potential synergistic interaction between climate and Bd by measuring prevalence of infection and level of infection per individual sampled (number of zoospores), across the dry and wet seasons for 2 yr (between 2005 and 2007). Infection levels in adult frogs were significantly higher during the dry season in both species studied, suggesting a cyclic pattern of dry/ cool-wet/warm climate-driven synergistic interaction. These results are consistent with ex situ experiments in which E. coqui infected with Bd were more susceptible to chytridiomycosis when subjected to limited water treatments resembling drought. Long-term data on the prevalence of Bd in the populations studied versus intensity of infection in individual frogs provided contradictory information. However, the conflicting nature of these data was essential to understand the status of Bd in the species and geographical area studied. We conclude that in Puerto Rico, Bd is enzootic, and vulnerability of eleutherodactylid frogs to this pathogen is related to seasonal climatic variables. Our data suggest a mechanism by which this disease can persist in tropical frog communities without decimation of its hosts, but that complex interactions during severe droughts may lead to population crashes. 相似文献
914.
da Silva Guimarães LM de Resende MD Lau D Rosse LN Alves AA Alfenas AC 《Genetics and molecular biology》2010,33(3):525-531
Chrysophorte cubensis induced canker occurs in nearly all tropical and subtropical regions where eucalypts are planted, causing losses in both wood quality and volume productivity, especially so in the warmer and more humid regions of Brazil. The wide inter and intra-specific genetic variability of resistance to canker among Eucalyptus species facilitates the selection of resistant plants. In this study, we evaluated resistance to this pathogen in five Eucalyptus grandis (G) and 15 E. urophylla (U) trees, as well as in 495 individuals from 27 progenies derived from crosses between the trees. In the field, six-months-old test seedlings were inoculated with C. cubensis. Lesion length in the xylem and bark was measured eight months later. The results demonstrated that xylem lesions could preferentially be used for the selection of resistant clones. Eight trees (7 U and 1 G) were susceptible, and the remainder (8 U and 4 G) resistant. Individual narrow and broad sense heritability estimates were 17 and 81%, respectively, thereby suggesting that canker resistance is quantitative and highly dependent on dominance and epistasis. 相似文献
915.
Baptista JC Machado MA Homem RA Torres PS Vojnov AA do Amaral AM 《Genetics and molecular biology》2010,33(1):146-153
The Gram-negative bacterium Xanthomonas axonopodis pv. citri, the causal agent of citrus canker, is a major threat to the citrus industry worldwide. Although this is a leaf spot pathogen, it bears genes highly related to degradation of plant cell walls, which are typically found in plant pathogens that cause symptoms of tissue maceration. Little is known on Xac capacity to cause disease and hydrolyze cellulose. We investigated the contribution of various open reading frames on degradation of a cellulose compound by means of a global mutational assay to selectively screen for a defect in carboxymethyl cellulase (CMCase) secretion in X. axonopodis pv. citri. Screening on CMC agar revealed one mutant clone defective in extracellular glycanase activity, out of nearly 3,000 clones. The insertion was located in the xpsD gene, a component of the type II secretion system (T2SS) showing an influence in the ability of Xac to colonize tissues and hydrolyze cellulose. In summary, these data show for the first time, that X. axonopodis pv. citri is capable of hydrolyzing cellulose in a T2SS-dependent process. Furthermore, it was demonstrated that the ability to degrade cellulose contributes to the infection process as a whole. 相似文献
916.
Veronica Marcos Phillip Latzin Andreas Hector Sebastian Sonanini Florian Hoffmann Martin Lacher Barbara Koller Philip Bufler Thomas Nicolai Dominik Hartl Matthias Griese 《Respiratory research》2010,11(1):32
Background
Inflammatory lung diseases are a major morbidity factor in children. Therefore, novel strategies for early detection of inflammatory lung diseases are of high interest. Bacterial lipopolysaccharide (LPS) is recognized via Toll-like receptors and CD14. CD14 exists as a soluble (sCD14) and membrane-associated (mCD14) protein, present on the surface of leukocytes. Previous studies suggest sCD14 as potential marker for inflammatory diseases, but their potential role in pediatric lung diseases remained elusive. Therefore, we examined the expression, regulation and significance of sCD14 and mCD14 in pediatric lung diseases.Methods
sCD14 levels were quantified in serum and bronchoalveolar lavage fluid (BALF) of children with infective (pneumonia, cystic fibrosis, CF) and non-infective (asthma) inflammatory lung diseases and healthy control subjects by ELISA. Membrane CD14 expression levels on monocytes in peripheral blood and on alveolar macrophages in BALF were quantified by flow cytometry. In vitro studies were performed to investigate which factors regulate sCD14 release and mCD14 expression.Results
sCD14 serum levels were specifically increased in serum of children with pneumonia compared to CF, asthma and control subjects. In vitro, CpG induced the release of sCD14 levels in a protease-independent manner, whereas LPS-mediated mCD14 shedding was prevented by serine protease inhibition.Conclusions
This study demonstrates for the first time the expression, regulation and clinical significance of soluble and membrane CD14 receptors in pediatric inflammatory lung diseases and suggests sCD14 as potential marker for pneumonia in children. 相似文献917.
Reginaldo Kisho Fukuchi Claudiane Arakaki Maria Isabel Veras Orselli Marcos Duarte 《Journal of biomechanics》2010,43(3):592-594
In this study, we evaluated alternative technical markers for the motion analysis of the pelvic segment. Thirteen subjects walked eight times while tri-dimensional kinematics were recorded for one stride of each trial. Five marker sets were evaluated, and we compared the tilt, obliquity, and rotation angles of the pelvis segment: (1) standard: markers at the anterior and posterior superior iliac spines (ASIS and PSIS); (2) markers at the PSIS and at the hip joint centers, HJCs (estimated by a functional method and described with clusters of markers at the thighs); (3) markers at the PSIS and HJCs (estimated by a predictive method and described with clusters of markers at the thighs); (4) markers at the PSIS and HJCs (estimated by a predictive method and described with skin-mounted markers at the thighs based on the Helen-Hayes marker set); (5) markers at the PSIS and at the iliac spines. Concerning the pelvic angles, evaluation of the alternative technical marker sets evinced that all marker sets demonstrated similar precision across trials (about 1°) but different accuracies (ranging from 1° to 3°) in comparison to the standard marker set. We suggest that all the investigated marker sets are reliable alternatives to the standard pelvic marker set. 相似文献
918.
María Victoria Frassa Marcelo Ceolín Marcos S. Dreon Horacio Heras 《Biochimica et Biophysica Acta - Proteins and Proteomics》2010,1804(7):1492-1499
There is little information on the egg proteins of gastropod mollusks. Here we focus on PV2, a novel neurotoxin from snail eggs, studying its size, shape, structure, and stability, using small angle X-ray scattering (SAXS), absorption and fluorescence spectroscopy, circular dichroism, electron microscopy and partial proteolysis. Results indicate that PV2 is a compact and well folded oligomer of 130 × 44 Å. It is an octamer of four 98 kDa heterodimers composed of 67 and 31 kDa subunits. Subunits are held together by disulfide bonds. Dimers are assembled into native PV2 by non-covalent forces. The larger subunit is more susceptible to proteolysis, indicating it is less compactly folded and/or more exposed. Quenching of tryptophan fluorescence showed a single class of tryptophyl side chains occluded in hydrophobic regions. Native structure shows loss of secondary structure (α+β) at 6 M urea or 60–70 °C; the effects on the quaternary structure suggest an unfolding without disassembling of the protein. The 3D model of PV2 presented here is the first for an egg proteinaceous neurotoxin in animals. 相似文献
919.
Carolina Mascayano Gabriel Núñez Waldo Acevedo Marcos Caroli Rezende 《Journal of molecular modeling》2010,16(5):1039-1045
The lipoxygenases (LOX) are a family of non-heme iron-containing dioxygenases which catalyze the stereospecific insertion
of molecular oxygen into arachidonic acid, leading to hydroxy derivatives as end products. In this work, we docked arachidonic
acid and two of its competitive inhibitors, flavonoids baicalein and quercetin, into the binding pockets of human 12- and
15-lipoxygenase. Steered molecular dynamics (SMD) simulations were employed to study the unbinding processes of the substrate
and inhibitors from the two isoforms. 相似文献
920.
Luciana Inácia Gomes Letícia Helena dos Santos Marques Martin Johannes Enk Maria Cláudia de Oliveira Paulo Marcos Zech Coelho Ana Rabello 《PLoS neglected tropical diseases》2010,4(4)