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Molecular characterization of Sarcocystis spp. isolates from marsupials of the genus Didelphis spp. through the analysis of mitocondrial and apicoplast genes, Internal Transcribed Spacers (ITS-1) and surface antigen genes

Grant number: 11/10550-2
Support Opportunities:Scholarships in Brazil - Doctorate (Direct)
Effective date (Start): August 01, 2011
Effective date (End): July 31, 2014
Field of knowledge:Agronomical Sciences - Veterinary Medicine - Preventive Veterinary Medicine
Principal Investigator:Rodrigo Martins Soares
Grantee:Samantha Yuri Oshiro Branco Valadas
Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade de São Paulo (USP). São Paulo , SP, Brazil


Sarcocystis neurona and Sarcocystis falcatula are very similar species that use marsupials of the genus Didelphis as definitive hosts. These mammals can participate as definitive hosts not only for these two parasites, but for other Sarcocystis such as Sarcocystis speeri and Sarcocystis lindsayi. Sarcocystis shed by opossums (except for S. neurona) can cause disease in a great variety of birds, being commonly associated with acute pulmonary sarcocistosis in zoos. Sarcocystis neurona is the most commonly associated parasite with the Equine Protozoal Myeloencephalitis in horses. In a previous work (unpublished results), we assessed the variability of Sarcocystis spp. isolated from opossums of the state of Rio Grande do Sul by sequencing the surface antigens genes. Unexpected results were found, possibly indicating two different lineages among the Sarcocystis isolates (genetically related to S. falcatula) that might exchange genes in possible sexual recombination processes. Also, a third Sarcocystis lineage, similar but not identical to S. neurona was detected. This last lineage does not share alleles with the former two. Our proposal is to study the genetic variation of the Sarocystis isolates from opossums captured in São Paulo, and those isolated from opossums of the state of Rio Grande do Sul by assessing other molecular markers in addition to the surface antigens genes. For that matter, we will analyze DNA Barcode markers. This marker allows the identification of a species by knowing one or more segments of standard gene sequences. The DNA Barcode is known as a universal marker present in most of the eukaryote organisms (for example the Apicomplexa phylum), making them a very powerful marker for phylogenetic studies. In this project, loci genes of the mitochondrial and apicoplast genome will be evaluated as well the internal transcribed spacer of the ribosomal locus. In summary, our hypothesis is: if there are two lineages Sarcocystis that exchange genes with each other, it implies that both lineages belong to a mono-specific group with high genotypic and antigenic variability. These results may have a great impact in our knowledge of the different Sarcocystis species that infect opossums in our environment and also in the epidemiology of the infections caused by these protozoans. (AU)

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Scientific publications
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
VALADAS, SAMANTHA Y. O. B.; DA SILVA, JULIANA I. G.; LOPES, ESTELA GALLUCCI; KEID, LARA B.; ZWARG, TICIANA; DE OLIVEIRA, ALICE S.; SANCHES, THAIS C.; JOPPERT, ADRIANA M.; PENA, HILDA F. J.; OLIVEIRA, TRICIA M. F. S.; et al. Diversity of Sarcocystis spp shed by opossums in Brazil inferred with phylogenetic analysis of DNA coding ITS1, cytochrome B, and surface antigens. Experimental Parasitology, v. 164, p. 71-78, . (11/11226-4, 11/10550-2)
SERCUNDES, MICHELLE KLEIN; OSHIRO BRANCO VALADAS, SAMANTHA YURI; KEID, LARA BORGES; FERREIRA SOUZA OLIVEIRA, TRICIA MARIA; FERREIRA, HELENA LAGE; DE ALMEIDA VITOR, RICARDO WAGNER; GREGORI, FABIO; SOARES, RODRIGO MARTINS. Filogenia molecular de Toxoplasmatinae: comparação entre inferências baseadas em sequências genéticas mitocondriais e de apicoplasto. Revista Brasileira de Parasitologia Veterinária, v. 25, n. 1, p. 82-89, . (11/10550-2)
Academic Publications
(References retrieved automatically from State of São Paulo Research Institutions)
VALADAS, Samantha Yuri Oshiro Branco. Molecular characterization of Sarcocystis spp. isolates from marsupials of the genus Didelphis spp. through the analysis of mitochondrial and apicoplast genes, internal transcribed spacer region (ITS-1) and surface antigen genes (SAGs). 2015. Doctoral Thesis - Universidade de São Paulo (USP). Faculdade de Medicina Veterinária e Zootecnia (FMVZ/SBD) São Paulo.

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