35 research outputs found
Ts6 and Ts2 from Tityus serrulatus venom induce inflammation by mechanisms dependent on lipid mediators and cytokine production
AbstractInflammatory mediators are thought to be involved in the systemic and local immune response induced by the Tityus serrulatus scorpion envenomation. New functional aspects of lipid mediators have recently been described. Here, we examine the unreported role of lipid mediators in cell recruitment to the peritoneal cavity after an injection with Ts2 or Ts6 toxins isolated from the T. serrulatus scorpion venom. In this report, we demonstrate that following a single intraperitoneal (i.p.) injection of Ts2 or Ts6 (250Â ÎĽg/kg) in mice, there was an induction of leukocytosis with a predominance of neutrophils observed at 4, 24, 48 and 96Â h. Moreover, total protein, leukotriene (LT)B4, prostaglandin (PG)E2 and pro-inflammatory cytokine levels were increased. We also observed an increase of regulatory cytokines, including interleukin (IL)-10, after the Ts2 injection. Finally, we observed that Ts2 or Ts6 injection in 5-lipoxygenase (LO) deficient mice and in wild type (WT) 129sv mice pre-treated with LTs and PGs inhibitors (MK-886 and celecoxib, respectively) a reduction the influx of leukocytes occurs in comparison to WT. The recruitment of these cells demonstrated a phenotype characteristic of neutrophils, macrophages, CD4 and CD8 lymphocytes expressing GR1+, F4/80+, CD3+/CD4+ and CD3+/CD8+, respectively. In conclusion, our data demonstrate that Ts2 and Ts6 induce inflammation by mechanisms dependent on lipid mediators and cytokine production. Ts2 may play a regulatory role whereas Ts6 exhibits pro-inflammatory activity exclusively
Celecoxib Improves Host Defense through Prostaglandin Inhibition during Histoplasma capsulatum
Pervasive gaps in Amazonian ecological research
Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4
While the increasing availability of global databases on ecological communities has advanced our knowledge
of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In
the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of
Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus
crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced
environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian
Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by
2050. This means that unless we take immediate action, we will not be able to establish their current status,
much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio
Transcription profile of Trichophyton rubrum conidia grown on keratin reveals the induction of an adhesin-like protein gene with a tandem repeat pattern
Pervasive gaps in Amazonian ecological research
Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost
Complement System and response of production of antibody in rats with hyperthyroidism
Tendo em vista a ocorrĂŞncia de alterações no sistema imune relacionadas ao hipertireoidismo e Ă participação do sistema complemento (SC) em processos imunolĂłgicos, torna-se importante investigar se os hormĂ´nios tireoidianos teriam algum efeito sobre o SC. O SC Ă© composto de uma sĂ©rie de proteĂnas sĂ©ricas e de membrana que estĂŁo envolvidas em processos da resposta imune. Considerando que os hormĂ´nios tireoidianos estĂŁo envolvidos em uma sĂ©rie de processos biolĂłgicos, e que tanto o hipo- quanto hipertireoidismo podem acarretar alterações importantes nestes processos, os objetivos deste trabalho foram estudar o impacto de nĂveis sĂ©ricos elevados de hormĂ´nios tireoidianos sobre a atividade do sistema complemento e produção de anticorpos. Foram utilizados ratos machos wistar para o modelo experimental de hipertireoidismo, investigando-se a atividade lĂtica das vias clássica/lectina e alternativa atravĂ©s de ensaios hemolĂticos; os nĂveis sĂ©ricos de fator B da via alternativa atravĂ©s do emprego de reagente deficiente de fator B; e a produção de anticorpos anti-hemácia de carneiro (SRBC) empregando ELISA (enzyme linked immunosorbent assay) e ensaios de plaque forming cell (PFC). O hipertireoidismo induzido nĂŁo resultou em alterações da atividade lĂtica das vias clássica/lectina. Entretanto, a elevação dos nĂveis sĂ©ricos de hormĂ´nios tireoidianos provocou uma redução da atividade lĂtica de via alternativa, de forma significante em doses de 1, 5, 50 e 100g de levotiroxina/200g de peso animal apĂłs 14 dias de tratamento, e com dose a partir de 0,15g de triiodotironina/200g de peso animal, apĂłs 7 e 12 dias de tratamento. Os nĂveis sĂ©ricos funcionais de fator B foram reduzidos nestas condições. AlĂ©m disso, ocorre redução da resposta de produção de anticorpos em ratos tratados com T3 e imunizados com SRBC. Estes resultados mostram que nĂveis elevados de hormĂ´nio tireoideano reduzem a capacidade funcional da via alternativa do SC , avaliada pelo desencadeamento da lise em decorrĂŞncia da interação com hemácias de coelho. Esta redução poderia levar a uma menor geração de fragmentos com atividade nos processos de seqĂĽestro e apresentação do antĂgeno e interação com as cĂ©lulas envolvidas na resposta imune, resultando em tĂtulos menores de anticorpos produzidos. Estudos adicionais sĂŁo necessários para avaliar estas possibilidades. As observações deste estudo podem auxiliar para o melhor entendimento do impacto biolĂłgico das disfunções hormonais sobre a atividade do sistema complemento.Considering the alterations of the immune system that occur in the hyperthyroidism, and the involvement of the complement system (CS) in immune processes, this work aimed to investigate the effect of high levels of thyroid hormones on the CS and on the antibody production. The CS comprehends a group of serum and membrane proteins which activation leads to the generation of protein fragments or complexes with important biologic functions, such as participation in events of the immune response. Wistar adult male rats treated with thyroid hormones were used as experimental model of hyperthyroidism, to evaluate the lytic activity of classical/lectin and alternative pathways of the CS through hemolytic assays; the serum levels of factor B employing serum deficient of this component (RB); and the production of anti-sheep red blood cells (SRBC) antibodies through enzyme linked immunosorbent (ELISA) and plaque forming cell (PFC) assays. Classic and lectin pathways activity was not affected in the hyperthyroidism. However in this condition the alternative pathway activity was significantly reduced at doses of 1; 5; 50 and 100 g of thyroxine (T4) /200g of animal weight/day after 14 days of treatment, or crescent doses starting from 0,15 g of triiodothyronine (T3) for periods of 7 and 12 days of treatment. The serum levels of factor B were also reduced in these conditions. In addition, there was a reduction of the antibody response in rats treated with T3 and immunized with SRBC. These results show that the functional capacity of alternative pathway is decreased in consequence of high levels of thyroid hormones as evaluated by its lytic potency triggered by the rabbit erythrocytes. This could them lead to a reduced generation of complement fragments active in antigen sequestering and presentation, and on the interaction of cells in the immune response decreasing the antibody production. Additional studies are required to evaluate these possibilities