| Grant number: | 13/02848-7 |
| Support Opportunities: | Scholarships abroad - Research Internship - Post-doctor |
| Start date until: | June 11, 2013 |
| End date until: | April 10, 2014 |
| Field of knowledge: | Biological Sciences - Parasitology - Protozoology of Parasites |
| Principal Investigator: | Otavio Henrique Thiemann |
| Grantee: | Marco Túlio Alves da Silva |
| Supervisor: | Norma W. Andrews |
| Host Institution: | Instituto de Física de São Carlos (IFSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil |
| Institution abroad: | University of Maryland, College Park, United States |
| Associated to the scholarship: | 11/24017-4 - Study of selenium metabolism in primitive eukaryotes, BP.PD |
Abstract Selenium (Se), the major metalloid micronutrient, occurs naturally in foods and feedstuffs almost exclusively in organic compounds and several evidences demonstrated that the supplementation with this element modified the course of different pathogens infections. However, the data are conflicting. Supplementary selenium associated with the current treatment (diminazene aceturate) for Trypanosoma evansi increased the survival of the infected mice, probable to modulate the immune response against the parasite. Mice feed with a deficient selenium diet presented susceptibility to Trypanosoma cruzi infection and increased severity of myopathy. Se supplementation alleviated heart muscle damage and reduced parasitemia and mortality in infected mice. In other hand, the selenium-deficient mouse infected with Trypanosoma musculi presented low parasitemia and infection was cleared after 16 days post-inoculation (PI), whereas control mice sustained the parasitemia until day 24 PI. It was reported a decreased severity of Salmonella typhimurium infection in Se-deficient rats and suggested that this response could have resulted from competition between host and parasite for the available Se. There was positive relationships between selenium concentrations and GPx1 activities in patients with cutaneous leishmaniasis (CL), suggesting that selenium has an important role in the pathophysiologic processes of cutaneous leishmaniasis. It was demonstrated that selenium levels and the activity of Gluatitone Peroxidade (GPx) of the CL patients were lower than those of the healthy controls, suggesting that low levels of selenium may be a host defense mechanism against Leishmania infection. As demonstrated selenoproteins (proteins that contain a rare amino acid selenocysteine, the major form of organic selenium) confer stress oxidative protection; therefore, it is possible that these members help the parasite to survive inside of macrophages or other cells. The project aim is observe the effects of selenium supplementation along Leishmania amazonensis infection in vitro and in vivo, evaluating NO production and selenoproteins expression. We intent to study the effects of absence or overexpression of selenoproteins in Leishmania and parameters as differentiation into metacyclic forms and intracellular replication of amastigotes will be analyzed. (AU) | |
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