Schwann cells as putative safe host cells for Leishmania amazonensis

Submitted by Sandra Infurna ([email protected]) on 2018-12-20T14:18:35Z No. of bitstreams: 1 suzane_cortereal_etal_IOC_2009.pdf: 131775 bytes, checksum: 082ac468bc8211d57b52efeded0ebd5f (MD5)Approved for entry into archive by Sandra Infurna ([email protected]) on 2018-12-20T14:25:00Z (GMT) No. of bitstreams: 1 suzane_cortereal_etal_IOC_2009.pdf: 131775 bytes, checksum: 082ac468bc8211d57b52efeded0ebd5f (MD5)Made available in DSpace on 2018-12-20T14:25:00Z (GMT). No. of bitstreams: 1 suzane_cortereal_etal_IOC_2009.pdf: 131775 bytes, checksum: 082ac468bc8211d57b52efeded0ebd5f (MD5) Previous issue date: 2009Universidade Federal do Rio de Janeiro. Instituto de Biofísica Carlos Chagas Filho. Laboratório de Neurobiologia do Desenvolvimento. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Biologia Estrutural. Rio de Janeiro, RJ. Brasil.Universidade Federal do Rio de Janeiro. Instituto de Biofísica Carlos Chagas Filho. Laboratório de Neurobiologia do Desenvolvimento. Rio de Janeiro, RJ, Brasil

Immunogold labeling and cerium cytochemistry of the enzyme ecto-5'-nucleotidase in promastigote forms of Leishmania species

We have applied both enzyme cytochemistry and immunological labeling techniques to characterize the enzyme 5'-nucleotidase (5'-Nase), at the ultrastructural level, in promastigote forms of four Leishmania species: Leishmania amazonensis, Leishmania mexicana, Leishmania donovani and Leishmania chagasi. The cerium phosphate staining was localized at the surface of the cell body, the flagellum and the flagellar pocket membranes of all the parasites studied. The immunogold labelling technique confirmed these results. In this report we localized 5'-Nase in L. chagasi and L. amazonensis which have been implicated respectively in visceral and cutaneous forms of leishmaniasis. In addition, we confirmed the localization of this phosphomonoesterase in the other two species studied. The superior quality of the images, obtained with both methodologies, confirms that these parasites possess mechanisms capable of hydrolyzing nucleotide monophosphates, and that the expression of 5'-Nase is associated with the outer surface of the plasma membrane

Transmission Electron Microscopy Analysis of Skin Lesions from Sporotrichosis Epidemic in Rio de Janeiro, Brazil

Made available in DSpace on 2015-08-19T13:49:19Z (GMT). No. of bitstreams: 2 license.txt: 1914 bytes, checksum: 7d48279ffeed55da8dfe2f8e81f3b81f (MD5) cassio_ferreira_etal_IOC_2015.pdf: 688620 bytes, checksum: 997564bf4f89db85e9299b220ab8f9b7 (MD5) Previous issue date: 2015Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Hanseníase. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Biologia Estrutural. Plataforma de Microscopia Eletrônica. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Biologia Estrutural. Plataforma de Microscopia Eletrônica. Rio de Janeiro, RJ, BrasilTransmission electron microscopy can yield useful information in a range of scientific fields; it is capable of imaging at a significantly higher resolution than light microscopes and has been a very useful tool in the identification of morphological changes of the dermis as well as assessment of changes in the extracellular matrix. Our aim is to characterize by electron microscopy the cellular profile of lesions caused by Sporothrix schenckii from the sporotrichosis epidemic in its zoonotic form that occurs in Rio de Janeiro, Brazil

Interactions between Leishmania mexicana mexicana promastigotes and amastigotes and murine peritoneal macrophages in vitro

Unstimulated adherent mouse peritoneal cells were cultured in vitro and infected with equal numbers of a single strain of Leishmania m. mexicana amastigotes (AM), virulent promastigotes (VP), avirulent promastigotes (AVP) and fixed promastigotes (FP). Duplicate May-Grünwald-Giemsa stained coverslips were examined at time intervals up to 13 days. By 3 hr post infection, the number of macrophages containing parasites varied between 60.5% (VP) and 84% (AM) for macrophages exposed to living parasites, compared to 6.5% for macrophages exposed for FP. However, variable numbers of parasites showed degenerative changes by 3 hr, and the number of macrophages containing morphologically intact parasites varied significantly between cells infected with AM (84%) and those infected with VP (42%) or AVP(40%). The mean number on intacte parasites/macrophage also differed significantly between AM-infected cells and living or fixed promastigotes-infected cells. Quantitation of intact and degenerated parasites indicated parasite multiplication, as well as destruction, in VP-infected cells and parasite survival and multiplication in AM-infecte monolayers; in contrast no evidence of parasite multiplication was seen in AVP-infected cells. Changes in the mono layer itself (cell loss and macrophage vacuolization) were also evaluated. These results suggest that crucial events determining the outcome of infection occur in the host-parasite relationship during the fist 24 hours of infection. These events are apparently influenced not only by parasite or host strain but by environmentally induced variation within a given strain

Differential modulation of ATP-induced P2X7-associated permeabilities to cations and anions of macrophages by infection with Leishmania amazonensis

Submitted by Sandra Infurna ([email protected]) on 2016-10-11T11:26:05Z No. of bitstreams: 1 suzana2_cortereal_etal_IOC_2011.pdf: 1791768 bytes, checksum: bbf46ad75d79e2c3985488ddf122b3da (MD5)Approved for entry into archive by Sandra Infurna ([email protected]) on 2016-10-11T11:34:34Z (GMT) No. of bitstreams: 1 suzana2_cortereal_etal_IOC_2011.pdf: 1791768 bytes, checksum: bbf46ad75d79e2c3985488ddf122b3da (MD5)Made available in DSpace on 2016-10-11T11:34:34Z (GMT). No. of bitstreams: 1 suzana2_cortereal_etal_IOC_2011.pdf: 1791768 bytes, checksum: bbf46ad75d79e2c3985488ddf122b3da (MD5) Previous issue date: 2011Universidade Federal do Rio de Janeiro. Instituto de Biofísica Carlos Chagas Filho (IBCCF). Rio de Janeiro, RJ, Brasil.Universidade Federal do Rio de Janeiro. Instituto de Biofísica Carlos Chagas Filho (IBCCF). Rio de Janeiro, RJ, Brasil.Universidade Federal do Rio de Janeiro. Instituto de Biofísica Carlos Chagas Filho (IBCCF). Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Rio de Janeiro, RJ, Brasil.Universidade Federal do Rio de Janeiro. Instituto de Biofísica Carlos Chagas Filho (IBCCF). Rio de Janeiro, RJ, Brasil.Universidade Federal do Rio de Janeiro. Instituto de Biofísica Carlos Chagas Filho (IBCCF). Rio de Janeiro, RJ, Brasil.Leishmania and other parasites display several mechanisms to subvert host immune cell function in order to achieve successful infection. The ATP receptor P2X7, an agonist-gated cation channel widely expressed in macrophages and other cells of the immune system, is also coupled to inflammasome activation, IL-1 beta secretion, production of reactive oxygen species, cell death and the induction of the permeabilization of the plasma membrane to molecules of up to 900 Da. P2X7 receptors can function as an effective microbicidal triggering receptor in macrophages infected with several microorganisms including Mycobacteria tuberculosis, Chlamydia and Leishmania. We have previously shown that its expression is up-regulated in macrophages infected with L. amazonensis and that infected cells also display an increase in P2X7-induced apoptosis and membrane permeabilization to some anionic fluorescent dyes. In an independent study we recently showed that the phenomenon of macrophage membrane permeabilization can involve at least two distinct pathways for cations and anions respectively. Here, we re-addressed the effects of ATP-induced P2X7-associated phenomena in macrophages infected with L. amazonensis and demonstrated that the P2X7-associated dye uptake mechanisms are differentially modulated. While the membrane permeabilization for anionic dyes is up-modulated, as previously described, the uptake of cationic dyes is strongly down-modulated. These results unveil new characteristics of two distinct permeabilization mechanisms associated with P2X7 receptors in macrophages and provide the first evidence indicating that these pathways can be differentially modulated in an immunologically relevant situation. The possible importance of these results to the L. amazonensis escape mechanism is discussed

Crithidia deanei infection in normal and dexamethasone–immunosuppressed Balb/c mice

Submitted by Sandra Infurna ([email protected]) on 2017-09-05T14:44:12Z No. of bitstreams: 1 susana_cortereal_etal_IOC_2010.pdf: 1759531 bytes, checksum: 944267f24db26d485dbb0d5e855cf933 (MD5)Approved for entry into archive by Sandra Infurna ([email protected]) on 2017-09-05T14:59:10Z (GMT) No. of bitstreams: 1 susana_cortereal_etal_IOC_2010.pdf: 1759531 bytes, checksum: 944267f24db26d485dbb0d5e855cf933 (MD5)Made available in DSpace on 2017-09-05T14:59:10Z (GMT). No. of bitstreams: 1 susana_cortereal_etal_IOC_2010.pdf: 1759531 bytes, checksum: 944267f24db26d485dbb0d5e855cf933 (MD5) Previous issue date: 2010Universidade Federal Fluminense. Departamento de Biologia Celular e Molecular.. Niterói, RJ, Brasil.Universidade Federal Fluminense. Departamento de Biologia Celular e Molecular.. Niterói, RJ, Brasil.Universidade Federal Fluminense. Departamento de Biologia Celular e Molecular.. Niterói, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Departamento de Micobacterioses. Rio de Janeiro, RJ. Brasil / Universidade do Estado do Rio de Janeiro. Faculdade de Ciências Médicas. Departamento de Patologia. Rio de Janeiro, RJ, Brasil.Universidade Federal Fluminense. Departamento de Biologia Celular e Molecular.. Niterói, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Biologia Estrutural. Rio de Janeiro, RJ. Brasil.Universidade Federal Fluminense. Instituto Biomédico. Departamento de Microbiologia e Parasitologia. Niterói, RJ, Brasil.Monoxenous trypanossomatids protozoa are not believed to cause in vivo infection in vertebrate hosts throughout their life cycle. However, there are reports mentioning some cases of HIVpositive patients who have presented opportunistic infections caused by these protozoa. Recently, we have demonstrated the in vitro infection of mouse dermal fibroblasts by these protozoa. The aim of the present work is to investigate the possibility of Crithidia deanei, a endosymbiont-bearing monoxenous trypanossomatid, infect BALB/c mice under or not Dexamethasone treatment. To attend it, distinct gro- ups of adult BALB/c mice were immunosuppressed with 50 mg/kg of Dexamethasone. This immunosuppressor was administered 24 hours before infection and daily, for 15 days after C. deanei inoculation. Control groups: C. deanei–inoculated animals but non-immunosuppressed and non-inoculated animals but immunosuppressed were also used. Light Microscopy analysis revealed an infection process characterized by the presence of the trypanossomatid inside dermal cells in the groups studied. The experimental inoculation resulted in a non-lethal infection characterized by the presence of the trypanossomatid inside dermal cells in the normal BALB/c mice, but notably, in the C. deanei–inoculated immunosuppressed group. These preliminary results lead to the following conclusions: 1) C. deanei is able to infect normal BALB/c mice; 2) the immunosupressed mice seemed to be more susceptible to the C. deanei infection compared to the control group. Besides C. deanei in dexamethasone-immunosuppressed mice provides a useful model for studies of monoxenous trypanosomatids ‘in vivo’ infection, resembling that one presumably occurring in imunodeficient individuals with AIDS