Virus Infections on Prion Diseased Mice Exacerbate Inflammatory Microglial Response

We investigated possible interaction between an arbovirus infection and the ME7 induced mice prion disease. C57BL/6, females, 6-week-old, were submitted to a bilateral intrahippocampal injection of ME7 prion strain (ME7) or normal brain homogenate (NBH). After injections, animals were organized into two groups: NBH (n=26) and ME7 (n=29). At 15th week after injections (wpi), animals were challenged intranasally with a suspension of Piry arbovirus 0.001% or with NBH. Behavioral changes in ME7 animals appeared in burrowing activity at 14 wpi. Hyperactivity on open field test, errors on rod bridge, and time reduction in inverted screen were detected at 15th, 19th, and 20th wpi respectively. Burrowing was more sensitive to earlier hippocampus dysfunction. However, Piry-infection did not significantly affect the already ongoing burrowing decline in the ME7-treated mice. After behavioral tests, brains were processed for IBA1, protease-resistant form of PrP, and Piry virus antigens. Although virus infection in isolation did not change the number of microglia in CA1, virus infection in prion diseased mice (at 17th wpi) induced changes in number and morphology of microglia in a laminar-dependent way. We suggest that virus infection exacerbates microglial inflammatory response to a greater degree in prion-infected mice, and this is not necessarily correlated with hippocampal-dependent behavioral deficits

ANÁLISE ANTIBACTERIANA DE UM FILTRADO CONTENDO CINCO BACTERIÓFAGOS AMAZÔNICOS GRANDES

A resistência bacteriana aos antibióticos é um problema de saúde pública com implicações notáveis no tratamento das infecções bacterianas, bem como no perfil epidemiológico dessas infecções em ambientes hospitalares e na comunidade, dada a transmissibilidade de agentes infecciosos bacterianos; portanto, alternativas aos antibióticos são urgentes para mitigar esse problema de saúde pública. Assim, uma busca de fagos de esgoto com potencial para biocontrole bacteriano foi realizada usando abordagens microbiológicas clássicas para avaliar sua resiliência às condições de armazenamento e sua atividade lítica sobre bactérias patogênicas, seguida de caracterização por microscopia eletrônica de transmissão. Como resultado, obteve-se um filtrado contendo cinco miovírus grandes capazes de lisar três espécies bacterianas clinicamente significativas e permanecer viáveis em armazenamento a 4°C por longos períodos, demonstrando o potencial para aplicações biotecnológicas no controle bacteriano

Early and Late Pathogenic Events of Newborn Mice Encephalitis Experimentally Induced by Itacaiunas and Curionópolis Bracorhabdoviruses Infection

In previous reports we proposed a new genus for Rhabdoviridae and described neurotropic preference and gross neuropathology in newborn albino Swiss mice after Curionopolis and Itacaiunas infections. In the present report a time-course study of experimental encephalitis induced by Itacaiunas and Curionopolis virus was conducted both in vivo and in vitro to investigate cellular targets and the sequence of neuroinvasion. We also investigate, after intranasal inoculation, clinical signs, histopathology and apoptosis in correlation with viral immunolabeling at different time points. Curionopolis and Itacaiunas viral antigens were first detected in the parenchyma of olfactory pathways at 2 and 3 days post-inoculation (dpi) and the first clinical signs were observed at 4 and 8 dpi, respectively. After Curionopolis infection, the mortality rate was 100% between 5 and 6 dpi, and 35% between 8 and 15 dpi after Itacaiunas infection. We identified CNS mice cell types both in vivo and in vitro and the temporal sequence of neuroanatomical olfactory areas infected by Itacaiunas and Curionopolis virus. Distinct virulences were reflected in the neuropathological changes including TUNEL immunolabeling and cytopathic effects, more intense and precocious after intracerebral or in vitro inoculations of Curionopolis than after Itacaiunas virus. In vitro studies revealed neuronal but not astrocyte or microglial cytopathic effects at 2 dpi, with monolayer destruction occurring at 5 and 7 dpi with Curionopolis and Itacaiunas virus, respectively. Ultrastructural changes included virus budding associated with interstitial and perivascular edema, endothelial hypertrophy, a reduced and/or collapsed small vessel luminal area, thickening of the capillary basement membrane, and presence of phagocytosed apoptotic bodies. Glial cells with viral budding similar to oligodendrocytes were infected with Itacaiunas virus but not with Curionopolis virus. Thus, Curionopolis and Itacaiunas viruses share many pathological and clinical features present in other rhabdoviruses but distinct virulence and glial targets in newborn albino Swiss mice brain

Detección de actividad de fosfatasa ácida en los hemocitos de Biomphalaria glabrata (Gastropoda: Planorbidae): un estudio en moluscos de la Región Amazónica, Brasil

Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Laboratório de Biologia e Eletrofisiologia em Células Parasitárias. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Laboratório de Microscopia Eletrônica. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Laboratório de Biologia e Eletrofisiologia em Células Parasitárias. Ananindeua, PA, Brasil.Foram utilizados hemócitos de planorbídeos da espécie Biomphalaria glabrata para a realização de citoquímica para detecção de atividade da fosfatase ácida, usando a técnica de laranja de acridina, com o objetivo de marcação de compartimentos ácidos citoplasmáticos. Essa espécie de caramujo é a mais utilizada para o estudo de interação parasito-hospedeiro devido à maior suscetibilidade em infectar-se pelo Schistosoma mansoni e por ser capaz de grande multiplicação parasitária em seus tecidos, apesar da atividade do seu sistema imunológico. A citoquímica ultraestrutural foi também utilizada para marcação de atividade da fosfatase ácida em inclusões citoplasmáticas limitadas por membrana. Os resultados mostram que o uso de laranja de acridina possibilita a marcação de compartimentos ácidos no interior de granulócitos; entretanto, essa marcação não ocorreu em hialinócitos, o que pode auxiliar na distinção desses dois tipos de células presentes na hemolinfa desse molusco. A citoquímica ultraestrutural possibilitou a visualização de depósitos eletrodensos localizados no interior dos grânulos citoplasmáticos constituídos basicamente por membranas, confirmando a atividade da fosfatase ácida.Planorbidae hemocytes of Biomphalaria glabrata were utilized for cytochemical detection of acid phosphatase activity, using acridine orange technique for marking the cytoplasmic acid compartments. This species of snail is the most widely used for studying host-parasite interaction due to greater susceptibility to becoming infected by Schistosoma mansoni, and to be capable of fast parasite multiplication in their tissues, despite the activity of its immune system. The ultrastructural cytochemistry was also used for marking the acid phosphatase activity in cytoplasmic inclusions limited by a membrane. The results show that acridine orange may be a marker for the acid compartments within granulocytes; however, this did not occur in hyalinocytes marking, which may help to distinguish these two types of cells present in the hemolymph of this mollusk. The ultrastructural cytochemistry enabled the visualization of electron dense deposits located within the cytoplasmic granules basically consisting of membranes, confirming the activity of acid phosphatase

The fine structure of the Garnia gonadati and its association with the host cell

This work was supported by Programa de Núcleos de Excelência (PRONEX), Financiadora de Estudos e Projetos (FINEP), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), and the Wellcome Trust.Ministério da Saúde. Fundação Nacional de Saúde. Instituto Evandro Chagas. Unidade de Microscopia Eletrônica. Belém, PA, Brasil.Universidade Federal do Pará. Departamento de Patologia. Centro de Ciências Biológicas. Belém, PA, Brazil.Ministério da Saúde. Fundação Nacional de Saúde. Instituto Evandro Chagas. Laboratório de Coccídeos. Belém, PA, Brasil.Universidade Federal do Rio de Janeiro. Instituto de Biofísica Carlos Chagas Filho. Laboratório de Ultraestrutura Celular Hertha Meyer. Rio de Janeiro, RJ, Brazil.Most of the studies on the fine structure of protozoa of the Apicomplexa group have been carried out with members of the Toxoplasma, Eimeria, and Plasmodium genera. In the present study we analyzed the fine structure of Garnia gonadoti parasitizing the red blood cells of the Amazonian reptile Gonatodes humeralis (Reptilia: Lacertilia). Transmission electron microscopy of thin sections showed that G. gonadoti presented all structures characteristic of the group, including the apicoplast. However, four special features were observed: (1) absence of the hemozoin (malarial) pigment; (2) a group of microtubules associated with the mitochondrion; (3) a vacuole containing electron-dense material, which resembled the acidocalcisome described in trypanosomatids; and (4) a special array of the host-cell endoplasmic reticulum around the parasitophorous vacuole

Hierarchical cluster analysis of three-dimensional reconstructions of unbiased sampled microglia shows not continuous morphological changes from stage 1 to 2 after multiple dengue infections in Callithrix penicillata

It is known that microglial morphology and function are related, but few studies have explored the subtleties of microglial morphological changes in response to specific pathogens. In the present report we quantitated microglia morphological changes in a monkey model of dengue disease with virus CNS invasion. To mimic multiple infections that usually occur in endemic areas, where higher dengue infection incidence and abundant mosquito vectors carrying different serotypes coexist, subjects received once a week subcutaneous injections of DENV3 (genotype III)-infected culture supernatant followed 24 hours later by an injection of anti-DENV2 antibody. Control animals received either weekly anti-DENV2 antibodies, or no injections. Brain sections were immunolabeled for DENV3 antigens and IBA-1. Random and systematic microglial samples were taken from the polymorphic layer of dentate gyrus for 3-D reconstructions, where we found intense immunostaining for TNFα and DENV3 virus antigens. We submitted all bi- or multimodal morphological parameters of microglia to hierarchical cluster analysis and found two major morphological phenotypes designated types I and II. Compared to type I (stage 1), type II microglia were more complex; displaying higher number of nodes, processes and trees and larger surface area and volumes (stage 2). Type II microglia were found only in infected monkeys, whereas type I microglia was found in both control and infected subjects. Hierarchical cluster analysis of morphological parameters of 3-D reconstructions of random and systematic selected samples in control and ADE dengue infected monkeys suggests that microglia morphological changes from stage 1 to stage 2 may not be continuous

Early and late neuropathological features of meningoencephalitis associated with Maraba virus infection

Universidade Estadual do Pará, Instituto Evandro Chagas, and Universidade Federal do Pará.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Laboratório de Microscopia Eletrônica. Ananindeua, PA, Brasil.Universidade Federal do Pará. Hospital Universitário João Barros Barreto. Instituto de Ciências Biológicas. Laboratório de Neurodegeneração e Infecção. Belém, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Laboratório de Microscopia Eletrônica. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Laboratório de Microscopia Eletrônica. Ananindeua, PA, Brasil / Universidade Federal do Pará. Hospital Universitário João Barros Barreto. Instituto de Ciências Biológicas. Laboratório de Neurodegeneração e Infecção. Belém, PA, Brasil.Universidade Federal do Pará. Núcleo de Medicina Tropical. Belém, PA, Brasil.Universidade Federal do Pará. Hospital Universitário João Barros Barreto. Instituto de Ciências Biológicas. Laboratório de Neurodegeneração e Infecção. Belém, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Laboratório de Microscopia Eletrônica. Ananindeua, PA, Brasil / Universidade Federal do Pará. Hospital Universitário João Barros Barreto. Instituto de Ciências Biológicas. Laboratório de Neurodegeneração e Infecção. Belém, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Laboratório de Microscopia Eletrônica. Ananindeua, PA, Brasil.Maraba virus is a member of the genus Vesiculovirus of the Rhabdoviridae family that was isolated in 1983 from sandflies captured in the municipality of Maraba, state of Pará, Amazônia, Brazil. Despite 30 years having passed since its isolation, little is known about the neuropathology induced by the Maraba virus. Accordingly, in this study the histopathological features, inflammatory glial changes, cytokine concentrations, and nitric oxide activity in the encephalon of adult mice subjected to Maraba virus nostril infection were evaluated. The results showed that 6 days after intranasal inoculation, severe neuropathological-associated disease signs appeared, including edema, necrosis and pyknosis of neurons, generalized congestion of encephalic vessels, and intra- and perivascular meningeal lymphocytic infiltrates in several brain regions. Immunolabeling of viral antigens was observed in almost all central nervous system (CNS) areas and this was associated with intense microglial activation and astrogliosis. Compared to control animals, infected mice showed significant increases in interleukin (IL)-6, tumor necrosis factor (TNF)-a, interferon (INF)-g, MCP-1, nitric oxide, and encephalic cytokine levels. We suggest that an exacerbated inflammatory response in several regions of the CNS of adult BALB/c mice might be responsible for their deaths

Microglial Metamorphosis in Three Dimensions in Virus Limbic Encephalitis: An Unbiased Pictorial Representation Based on a Stereological Sampling Approach of Surveillant and Reactive Microglia

Microglia influence pathological progression in neurological diseases, reacting to insults by expressing multiple morphofunctional phenotypes. However, the complete morphological spectrum of reactive microglia, as revealed by three-dimensional microscopic reconstruction, has not been detailed in virus limbic encephalitis. Here, using an anatomical series of brain sections, we expanded on an earlier Piry arbovirus encephalitis study to include CA1/CA2 and assessed the morphological response of homeostatic and reactive microglia at eight days post-infection. Hierarchical cluster and linear discriminant function analyses of multimodal morphometric features distinguished microglial morphology between infected animals and controls. For a broad representation of the spectrum of microglial morphology in each defined cluster, we chose representative cells of homeostatic and reactive microglia, using the sum of the distances of each cell in relation to all the others. Based on multivariate analysis, reactive microglia of infected animals showed more complex trees and thicker branches, covering a larger volume of tissue than in control animals. This approach offers a reliable representation of microglia dispersion in the Euclidean space, revealing the morphological kaleidoscope of surveillant and reactive microglia morphotypes. Because form precedes function in nature, our findings offer a starting point for research using integrative methods to understand microglia form and function