Parasites or Cohabitants: Cruel Omnipresent Usurpers or Creative “Éminences Grises”?

This paper presents many types of interplays between parasites and the host, showing the history of parasites, the effects of parasites on the outcome of wars, invasions, migrations, and on the development of numerous regions of the globe, and the impact of parasitic diseases on the society and on the course of human evolution. It also emphasizes the pressing need to change the look at the parasitism phenomenon, proposing that the term “cohabitant” is more accurate than parasite, because every living being, from bacteria to mammals, is a consortium of living beings in the pangenome. Even the term parasitology should be replaced by cohabitology because there is no parasite alone and host alone: both together compose a new adaptive system: the parasitized-host or the cohabitant-cohabited being. It also suggests switching the old paradigm based on attrition and destruction, to a new one founded on adaptation and living together

A identidade do torcedor no país do futebol

Consiste em uma busca pela identidade do torcedor de futebol com o seu time e com a seleção nacional. Fazendo um desenvolvimento histórico e sociológico do esporte no Brasil, podemos ver que a construção da nossa identidade como o país do futebol se deu após uma intensa luta no campo social e simbólico para definir qual seria o caráter do esporte no país. Através de uma revisão bibliográfica, nós trabalhamos a origem dos clubes e o pioneirismo das elites no futebol nacional, como o futebol se popularizou a tal ponto de fazer parte do cotidiano, alimentando comparações metafóricas para a vida. A medida em que esses clubes de futebol se desenvolvem como se cria a identidade dos torcedores, que apesar de rivais se unem em torno da seleção brasileira e do ideal nacional, e em casos onde as tensões da arquibancada extrapolam o estádio e alcançam a vida social, ou o inverso quando são dramatizadas pelas torcidas. E para os dias atuais, como a globalização influi no jogo e nessa organização simbólica, e como o mercado pode mudar as relações do torcedor com seu objeto de paixão

Cytochemical techniques and energy-filtering transmission electron microscopy applied to the study of parasitic protozoa

The study of parasitic protozoa plays a major role in cell biology, biochemistry and molecular biology. Numerous cytochemical techniques have been developed in order to unequivocally identify the nature of subcellular compartments. Enzyme and immuno-cytochemistry allow the detection of, respectively, enzymatic activity products and antigens in particular sites within the cell. Energy-filtering transmission electron microscopy permits the detection of specific elements within such compartments. These approaches are particularly useful for studies employing antimicrobial agents where cellular compartments may be destroyed or remarkably altered and thus hardly identified by standard methods of observation. In this regard cytochemical and spectroscopic techniques provide valuable data allowing the determination of the mechanisms of action of such compounds

Computed tomography imaging strategies and perspectives in orbital fractures

OBJECTIVE: The objective of this study was to demonstrate the sensitivity and specificity of multislice computed tomography (CT) for diagnosis of orbital fractures following different protocols, using an independent workstation. MATERIALS AND METHODS: CT images of 36 patients with maxillofacial fractures (symptomatic to orbit region) who were submitted to multislice CT scanning were analyzed, retrospectively. The images were interpreted based on 5 protocols, using an independent workstation: 1) axial (original images); 2) multiplanar reconstruction (MPR); 3) 3D images; 4) association of axial/MPR/3D images and 5) coronal images. The evaluated anatomical sites were divided according to the orbital walls: lateral (with or without zygomatic frontal process fracture); medial; superior (roof) and inferior (anterior, medial). The collected data were analyzed statistically using a validity test (Youden's J index;

Identification, characterization and localization of chagasin, a tight-binding cysteine protease inhibitor in Trypanosoma cruzi

Lysosomal cysteine proteases from mammalian cells and plants are regulated by endogenous tight-binding inhibitors from the cystatin superfamily. The presence of cystatin-like inhibitors in lower eukaryotes such as protozoan parasites has not yet been demonstrated, although these cells express large quantities of cysteine proteases and may also count on endogenous inhibitors to regulate cellular proteolysis. Trypanosoma cruzi, the causative agent of Chagas heart disease, is a relevant model to explore this possibility because these intracellular parasites rely on their major lysosomal cysteine protease (cruzipain) to invade and multiply in mammalian host cells. Here we report the isolation, biochemical characterization, developmental stage distribution and subcellular localization of chagasin, an endogenous cysteine protease inhibitor in T. cruzi. We used high temperature induced denaturation to isolate a heat-stable cruzipain-binding protein (apparent molecular mass, 12 kDa) from epimastigote lysates. This protein was subsequently characterized as a tight-binding and reversible inhibitor of papain-like cysteine proteases. Immunoblotting indicated that the expression of chagasin is developmentally regulated and inversely correlated with that of cruzipain. Gold-labeled antibodies localized chagasin to the flagellar pocket and cytoplasmic vesicles of trypomastigotes and to the cell surface of amastigotes. Binding assays performed by probing living parasites with fluorescein (FITC)-cruzipain or FITC-chagasin revealed the presence of both inhibitor and protease at the cell surface of amastigotes. The intersection of chagasin and cruzipain trafficking pathways may represent a checkpoint for downstream regulation of proteolysis in trypanosomatid protozoa

Parasite, Compartments, and Molecules: Trick versus Treatment on Chagas Disease

Chagas disease, caused by the protozoan Trypanosoma cruzi, is endemic to Latin America, standing out as a socio-economic problem for low-income tropical populations. Such disease affects millions of people worldwide and emerges in nonendemic areas due to migration and climate changes. The current chemotherapy is restricted to two nitroderivatives (benznidazole and nifurtimox), which is unsatisfactory due to limited efficacy (particularly in chronic phase) and adverse side effects. T. cruzi life cycle is complex, including invertebrate and vertebrate hosts and three developmental forms (epimastigotes, trypomastigotes, and amastigotes). In this chapter, we will discuss promising cellular and molecular targets present in the vertebrate-dwelling forms of the parasite (trypomastigotes and amastigotes). Among the cellular targets, the mitochondrion is the most frequently studied; while among the molecular ones, we highlight squalene synthase, C14α-sterol demethylase, and cysteine proteases. In this scenario, proteomics becomes a valuable tool for the identification of other molecular targets, and some previously identified candidates will be also discussed. Multidisciplinary studies are needed to identify novel key molecules in T. cruzi in order to increase trypanocidal activity and reduce mammalian toxicity, ensuring the development of novel drugs for Chagas disease

DETC Induces Leishmania Parasite Killing in Human In Vitro and Murine In Vivo Models: A Promising Therapeutic Alternative in Leishmaniasis

Background: Chemotherapy remains the primary tool for treatment and control of human leishmaniasis. However, currently available drugs present serious problems regarding side-effects, variable efficacy, and cost. Affordable and less toxic drugs are urgently needed for leishmaniasis. Methodology/Principal Findings: We demonstrate, by microscopy and viability assays, that superoxide dismutase inhibitor diethyldithiocarbamate (DETC) dose-dependently induces parasite killing (p,0.001) and is able to ??????sterilize?????? Leishmania amazonensis infection at 2 mM in human macrophages in vitro. We also show that DETC-induced superoxide production (p,0.001) and parasite destruction (p,0.05) were reverted by the addition of the antioxidant N-acetylcysteine, indicating that DETC-induced killing occurs through oxidative damage. Furthermore, ultrastructural analysis by electron microscopy demonstrates a rapid and highly selective destruction of amastigotes in the phagosome upon DETC treatment, without any apparent damage to the host cell, including its mitochondria. In addition, DETC significantly induced parasite killing in Leishmania promastigotes in axenic culture. In murine macrophages infected with Leishmania braziliensis, DETC significantly induced in vitro superoxide production (p = 0.0049) and parasite killing (p = 0.0043). In vivo treatment with DETC in BALB/C mice infected with Leishmania braziliensis caused a significant decrease in lesion size (p,0.0001), paralleled by a 100-fold decrease (p = 0.0087) in parasite burden. Conclusions/Significance: Due to its strong leishmanicidal effect in human macrophages in vitro, its in vivo effectiveness in a murine model, and its previously demonstrated in vivo safety profile in HIV treatment, DETC treatment might be considered as a valuable therapeutic option in human leishmaniasis, including HIV/Leishmania co-infection

Babesia microti infection changes host spleen architecture and is cleared by a Th1 immune response

Babesia microti is a malaria-like parasite, which infects ~2000 people annually, such that babesiosis is now a notifiable disease in the United States. Immunocompetent individuals often remain asymptomatic and are tested only after they feel ill. Susceptible C3H/HeJ mice show several human-like disease manifestations and are ideal to study pathogenesis of Babesia species. In this study, we examined parasitemia of B. microti at different time points and assessed its impact on hemoglobin levels in blood, on spleen pathology and overall immune response in C3H/HeJ mice. Peak parasitemia of 42.5% was immediately followed by diminished hemoglobin level. Parasitemia at 21 days of infection was barely detectable by microscopy presented 5.7 × 108 to 5.9 × 109 B. microti DNA copies confirming the sensitivity of our qPCR. We hypothesize that qPCR detects DNA released from recently lysed parasites or from extracellular B. microti in blood, which are not easily detected in blood smears and might result in under-diagnosis of babesiosis in patients. Splenectomized patients have been reported to show increased babesiosis severity and result in high morbidity and mortality. These results emphasize the importance of splenic immunity in resolution of B. microti infection. Splenomegaly in infected mice associated with destruction of marginal zone with lysed erythrocytes and released B. microti life forms in our experiments support this premise. At conclusion of the experiment at 21 days post-infection, significant splenic B and T cells depletion and increase in macrophages levels were observed in B. microti infected mice suggesting a role of macrophage in disease resolution. Infected mice also showed significantly higher plasmatic concentration of CD4 Th1 cells secreted cytokines such as IL-2 and IFN-γ while cytokines such as IL-4, IL-5, and IL-13 secreted by Th2 cells increase was not always significant. Thus, Th1 cells-mediated immunity appears to be important in clearance of this intracellular pathogen. Significant increase in IL-6 that promotes differentiation of Th17 cells was observed but it resulted in only moderate change in IL-17A, IL-17F, IL-21, and IL-22, all secreted by Th17 cells. A similar immune response to Trypanosoma infection has been reported to influence the clearance of this protozoan, and co-infecting pathogen(s)

Mulher e ficção: as personagens femininas em "Os anos"

A pesquisa apresentada neste artigo buscou identificar as características presentes nas personagens femininas do livro Os anos, da autora inglesa Virginia Woolf. A partir dessa identificação, é possível fazer uma melhor análise de seu enredo, contexto e até mesmo a inserção de Woolf na crítica feminista. Com a leitura de teóricas na área de autoria feminina e dos textos críticos de Virginia, como Um teto todo seu, Women and writing e Mulheres e ficção, foi feito um estudo sobre o papel da autora mulher na literatura, como a criação de personagens femininas por essas escritoras é capaz de mudar a visão dos estereótipos até então existentes. Após esta pesquisa crítica, seguiu-se a leitura do livro em questão, buscado as características esperadas nas personagens. O resultado foi mais satisfatório que o esperado, com uma profusão de personalidades, destinos e críticas embutidas a tais protagonistas.