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Pincerati M.R.,Federal University of Parana | Dalla-Costa R.,Federal University of Parana | Pavoni D.P.,Federal University of Parana | Pavoni D.P.,Instituto Carlos Chagas Fiocruz | Petzl-Erler M.L.,Federal University of Parana
International Journal of Immunogenetics | Year: 2010

CD28 and cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) are two receptors that have complementary functions in control of T-cell activation. Polymorphisms of their genes, CD28 and CTLA4, might confer differential susceptibility to diseases resulting from unbalanced or inefficient immune responses. Thus far, little is known about the CD28 polymorphism in populations and even for CTLA4 just one or two single nucleotide polymorphisms (SNPs) are usually analysed. To assess the allelic and haplotypic diversity and linkage disequilibrium in the Brazilian population, two samples differing according to predominant ancestry - African or European - have been analysed for seven SNPs, CD28 -372(G>A), and int3 17(T>C); CTLA4 -1722(T>C), -1577(G>A) -318(C>T), 49(A>G), 6230(G>A) also named CT60, and three microsatellites, CD28 (CAA)n, CTLA4 (AT)n and D2S72 (CA)n. The two population strata show little differentiation, the only significant differences being the allele frequencies of the CTLA4 -1577(G>A) SNP and the CTLA4 (AT)n microsatellite (P = 0.018 and P = 0.007, respectively). Linkage disequilibrium is high, especially between the CTLA4 polymorphisms. However, low r 2 values indicate that none of the markers is a tag SNP in these populations. These results provide valuable information for optimal selection of markers for use in future association studies. We conclude that disease association studies and functional studies addressing the possible consequences of polymorphisms of the 2q33 genomic region should consider haplotypic data besides analysis of individual polymorphisms. © 2010 Blackwell Publishing Ltd.

Melo F.T.V.,Laboratorio Of Biologia Celular | Giese E.G.,Laboratorio Of Biologia Celular | Furtado A.P.,Laboratorio Of Biologia Celular | Soares M.J.,Instituto Carlos Chagas Fiocruz | And 3 more authors.
Memorias do Instituto Oswaldo Cruz | Year: 2011

The family Nematotaeniidae, tapeworms commonly found in the small intestines of amphibians and reptiles, includes 27 recognised species distributed among four genera: Bitegmen Jones, Cylindrotaenia Jewell, Distoichometra Dickey and Nematotaenia Lühe. The taxonomy of these cestodes is poorly defined, due in part to the difficulties of observing many anatomical traits. This study presents and describes a new genus and species of nematotaeniid parasite found in cane toads (Rhinella marina) from eastern Brazilian Amazonia. The cestodes were collected during the necropsy of 20 hosts captured in the urban area of Belém, Pará. The specimens were fixed and processed for light microscopy, scanning electron microscopy (SEM) and three-dimensional (3D) reconstruction. Samples were also collected for molecular analyses. The specimens presented a cylindrical body, two testes and paruterine organs. However, they could not be allocated to any of the four existing nematotaeniid genera due to the presence of two each of dorsal compact medullary testes, cirri, cirrus pouches, genital pores, ovaries and vitelline glands per mature segment. Lanfrediella amphicirrus gen. nov. sp. nov. is the first nematotaeniid studied using Historesin analysis, SEM and 3D reconstruction, and it is the Second taxon for which molecular data have been deposited in GenBank.

Eger I.,Instituto Carlos Chagas Fiocruz | Eger I.,Vale do Itajai University | Soares M.J.,Instituto Carlos Chagas Fiocruz
Journal of Microbiological Methods | Year: 2012

Here we describe the visualization by confocal microscopy of ingested gold (15. nm)-labeled transferrin in epimastigote forms of the protozoan Trypanosoma cruzi. Intracellular gold labeling was evident at two sites, which represent the bottom of the cytopharynx and the reservosomes. The gold tracer was best observed by confocal microscopy by using the 633. nm excitation wavelength. Intracellular gold clusters larger than 60. nm could be visualized by either gold reflection (light scattering) or photoluminescence modes. The gold reflection mode, the gold photoluminescence mode and the anti-transferrin immunofluorescence image of gold-labeled transferrin showed co-localization, thus demonstrating that the gold visualization modes did not represent artifacts or mislocalization of the biomarker. Visualization of protein-gold nanoparticle complexes by confocal microscopy thus emerges as a promising imaging tool to explore the endocytic pathway in trypanosomes and other cell types, as well as to perform immunolocalization studies using gold-labeled secondary antibodies. © 2012 Elsevier B.V.

Cardoso J.,Instituto Carlos Chagas Fiocruz | Soares M.J.,Instituto Carlos Chagas Fiocruz
Memorias do Instituto Oswaldo Cruz | Year: 2010

Citral, the main constituent of lemongrass (Cymbopogon citratus) essential oil, was added to Trypanosoma cruzi cultures grown in TAU3AAG medium to observe the effect on the epimastigote-to-trypomastigote differentiation process (metacyclogenesis). Our results showed that citral (20 μg/mL) did not affect epimastigote viability or inhibit the differentiation process. Concentrations higher than 60 μg/mL, however, led to 100% cell death (both epimastigote and trypomastigote forms). Although epimastigotes incubated with 30 μg/mL citral were viable and able to adhere to the substrate, we observed around 50% inhibition in metacyclogenesis, with a calculated concentration that inhibited metacyclogenesis by 50% after 24 h (IC50/24 h) of about 31 μg/mL. Treatment with 30 μg/mL citral did not hinder epimastigote multiplication because epimastigote growth resumed when treated cells were transferred to a drugfree liver infusion tryptose culture medium. Metacyclogenesis was almost totally abolished at 40 μg/mL after 24 h of incubation. Furthermore, the metacyclic trypomastigotes obtained in vitro were similarly susceptible to citral, with an IC50/24 h, concentration that killed 50% of the cells after 24 h, of about 24.5 μg/mL. Therefore, citral appears to be a good candidate as an inhibitory drug for further studies analyzing the T. cruzi metacyclogenesis process.

Mosimann A.L.P.,Instituto Carlos Chagas Fiocruz | Bordignon J.,Instituto Carlos Chagas Fiocruz | Mazzarotto G.C.A.,Instituto Carlos Chagas Fiocruz | Motta M.C.M.,Federal University of Rio de Janeiro | And 2 more authors.
Memorias do Instituto Oswaldo Cruz | Year: 2011

Brevidensoviruses have an encapsidated, single-stranded DNA genome that predominantly has a negative polarity. In recent years, they have received particular attention due to their potential role in the biological control of pathogenic arboviruses and to their unnoticed presence in cell cultures as contaminants. In addition, brevidensoviruses may also be useful as viral vectors. This study describes the first genetic and biological characterization of a mosquito densovirus that was isolated in Brazil; moreover, we examined the phylogenetic relationship between this isolate and the other brevidensoviruses. We further demonstrate that this densovirus has the potential to be used to biologically control dengue virus (DENV) infection with in vitro co-infection experiments. The present study provides evidence that this densovirus isolate is a fast-spreading virus that affects cell growth and DENV infection.

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