LILIAN DE OLIVEIRA GUIMARAES
Projetos de Pesquisa
Unidades Organizacionais
LIM/49 - Laboratório de Protozoologia, Hospital das Clínicas, Faculdade de Medicina
4 resultados
Resultados de Busca
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- Merozoite surface protein-1 genetic diversity in Plasmodium malariae and Plasmodium brasilianum from Brazil(2015) GUIMARAES, Lilian O.; WUNDERLICH, Gerhard; ALVES, Joao M. P.; BUENO, Marina G.; ROEHE, Fabio; CATAO-DIAS, Jose L.; NEVES, Amanda; MALAFRONTE, Rosely S.; CURADO, Izilda; DOMINGUES, Wilson; KIRCHGATTER, KarinBackground: The merozoite surface protein 1 (MSP1) gene encodes the major surface antigen of invasive forms of the Plasmodium erythrocytic stages and is considered a candidate vaccine antigen against malaria. Due to its polymorphisms, MSP1 is also useful for strain discrimination and consists of a good genetic marker. Sequence diversity in MSP1 has been analyzed in field isolates of three human parasites: P. falciparum, P. vivax, and P. ovale. However, the extent of variation in another human parasite, P. malariae, remains unknown. This parasite shows widespread, uneven distribution in tropical and subtropical regions throughout South America, Asia, and Africa. Interestingly, it is genetically indistinguishable from P. brasilianum, a parasite known to infect New World monkeys in Central and South America. Methods: Specific fragments (1 to 5) covering 60 % of the MSP1 gene (mainly the putatively polymorphic regions), were amplified by PCR in isolates of P. malariae and P. brasilianum from different geographic origin and hosts. Sequencing of the PCR-amplified products or cloned PCR fragments was performed and the sequences were used to construct a phylogenetic tree by the maximum likelihood method. Data were computed to give insights into the evolutionary and phylogenetic relationships of these parasites. Results: Except for fragment 4, sequences from all other fragments consisted of unpublished sequences. The most polymorphic gene region was fragment 2, and in samples where this region lacks polymorphism, all other regions are also identical. The low variability of the P. malariae msp1 sequences of these isolates and the identification of the same haplotype in those collected many years apart at different locations is compatible with a low transmission rate. We also found greater diversity among P. brasilianum isolates compared with P. malariae ones. Lastly, the sequences were segregated according to their geographic origins and hosts, showing a strong genetic and geographic structure. Conclusions: Our data show that there is a low level of sequence diversity and a possible absence of allelic dimorphism of MSP1 in these parasites as opposed to other Plasmodium species. P. brasilianum strains apparently show greater divergence in comparison to P. malariae, thus P. malariae could derive from P. brasilianum, as it has been proposed.
- First molecular screening of Plasmodium species in ungulates from Southern Brazil(2018) SANTOS, L. C. Dos; GUIMARãES, L. De Oliveira; GRAZZIOTIN, A. L.; MORAIS, W. De; CUBAS, Z. S.; OLIVEIRA, M. J. De; VIEIRA, R. F. Da Costa; BIONDO, A. W.; KIRCHGATTER, K.Objective: Despite malaria epidemiology has been extensively studied in primates, few studies were conducted in ungulates. After half a century without descriptions of Plasmodium spp. in deer since its first identification, recent research has rediscovered Plasmodium on ungulates in Africa, Asia, North America and South America, including Central Brazil. Here, a captive herd was evaluated in southern Brazil using light microscopy and PCR. DNA samples were tested for fragment amplification of two Plasmodium spp. genes: mitochondrial cytochrome b and small subunit ribosomal RNA. Results: All analyses were negative. However, the tests were performed on samples that were collected at a single time point, and parasitemia may fluctuate over the parasite's life cycle. Thus, the possibility of occult infection cannot be ruled out. Despite the negative results of all of the methods applied, it cannot be categorically stated that these animals are free from Plasmodium sp. infection. Further monitoring and/or multiple sequential sampling may improve the success rate of detecting parasites. Moreover, although this survey of Plasmodium represents the first molecular study on ungulate malaria parasites from Southern Brazil, further analysis of samples from different ungulate species is important for characterizing the epidemiology of Plasmodium of these mammals in this region. © 2018 The Author(s).
- The genetic diversity of Plasmodium malariae and Plasmodium brasilianum from human, simian and mosquito hosts in Brazil(2012) GUIMARAES, L. O.; BAJAY, M. M.; WUNDERLICH, G.; BUENO, M. G.; ROEHE, F.; CATAO-DIAS, J. L.; NEVES, A.; MALAFRONTE, R. S.; CURADO, I.; KIRCHGATTER, K.Plasmodium malariae is a protozoan parasite that causes malaria in humans and is genetically indistinguishable from Plasmodium brasilianum, a parasite infecting New World monkeys in Central and South America. P. malariae has a wide and patchy global distribution in tropical and subtropical regions, being found in South America, Asia, and Africa. However, little is known regarding the genetics of these parasites and the similarity between them could be because until now there are only a very few genomic sequences available from simian Plasmodium species. This study presents the first molecular epidemiological data for P. malariae and P. brasilianum from Brazil obtained from different hosts and uses them to explore the genetic diversity in relation to geographical origin and hosts. By using microsatellite genotyping, we discovered that of the 14 human samples obtained from areas of the Atlantic forest, 5 different multilocus genotypes were recorded, while in a sample from an infected mosquito from the same region a different haplotype was found. We also analyzed the longitudinal change of circulating plasmodial genetic profile in two untreated non-symptomatic patients during a 12-months interval. The circulating genotypes in the two samples from the same patient presented nearly identical multilocus haplotypes (differing by a single locus). The more frequent haplotype persisted for almost 3 years in the human population. The allele Pm09-299 described previously as a genetic marker for South American P. malariae was not found in our samples. Of the 3 non-human primate samples from the Amazon Region, 3 different multilocus genotypes were recorded indicating a greater diversity among isolates of P. brasilianum compared to P. malariae and thus, P. malariae might in fact derive from P. brasilianum as has been proposed in recent studies. Taken together, our data show that based on the microsatellite data there is a relatively restricted polymorphism of P. malariae parasites as opposed to other geographic locations.
- Survey of Plasmodium spp. in Free-Ranging Neotropical Primates from the Brazilian Amazon Region impacted by Anthropogenic Actions(2013) BUENO, Marina G.; ROHE, Fabio; KIRCHGATTER, Karin; SANTI, Silvia M. F. Di; GUIMARAES, Lilian O.; WITTE, Carmel L.; COSTA-NASCIMENTO, Maria J.; TONIOLO, Christina R. C.; CATAO-DIAS, Jose LuizThis study investigated Plasmodium spp. infection in free-ranging neotropical primates from Brazilian Amazon regions under the impact of major anthropogenic actions. Blood samples from 19 new world primates were collected and analyzed with microscopic and molecular procedures. The prevalence of Plasmodium infection was 21.0% (4/19) and PCR positive samples were identified as P. brasilianum. Considering the social-economic changes that the Amazon is facing, the prevalence of P. brasilianum infection highlights the necessity to closely monitor the movement of both human and non-human primate populations, in order to mitigate pathogen exposure and the introduction of new agents into previously na < ve areas.