Navegando por Orientadores "NAGAMACHI, Cleusa Yoshiko"

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Alterações genéticas e epigenéticas em meningiomas na população paraense
(Universidade Federal do Pará, 2013-07-17) BASTOS, Carlos Eduardo Matos Carvalho; ANSELMO, Nilson Praia; http://lattes.cnpq.br/6518287721873199; NAGAMACHI, Cleusa Yoshiko; http://lattes.cnpq.br/8887641213110093
Meningiomas are the most common intracranial tumors that originate from the meninges surrounding the brain and spinal cord. Despite meningiomas were among the first solid neoplasms to be studied cytogenetically, little is known about their genetic and epigenetic profile. This study aimed to investigate genetic and epigenetic alterations that could contribute to tumor initiation and progression in meningiomas in the population of Pará, Brazil. This thesis is subdivided into three chapters. In Chapter I we investigated the association between the MTHFR C677T and meningioma in 23 patients in the population of Pará. A total of 96 healthy individuals with no previous pre-neoplastic lesions were selected for the control group. This association was not found. Although not statistically significant, our observation suggests that the TT genotype increases the risk of developing meningioma when compared to CC genotype. In Chapter II we evaluated the methylation pattern in two members of microRNA124 family in meningiomas in the population of Pará. Hypermethylation of the promoter region of miRN124a2 and miRNA124a3 appears to be a frequent event, as was found in 73.9% and 69.56% of the samples, respectively. In Chapter III, we analyzed the methylation pattern of the APC, BRCA1, CDH1, CDH13, CDKN2A, DAPK1, ESR1, FHIT, GSTP1, MGMT, MLH1, NEUROG1, PDLIM4, PTEN, Rb, RASSF1, RUNX3, SOCS1, TIMP3, TP73, VHL and WIF1 genes in a grade I and in a grade II meningiomas through an assay developed by MethylScreen. Pattern of methylation of CDKN2B was also analyzed in 25 patients with meningioma through bisulfite conversion, PCR and direct sequencing. RASSF1A was methylated in 16.73% and 63.66% of the CpG sites analyzed in the grade I and grade II meningioma, respectively. RUNX3 is methylated only in grade II meningioma in 52.88% of the CpG sites analyzed. Our results point to the importance of epigenetic changes in tumorigenesis and tumor progression in meningiomas.
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Análise citogenética de duas espécies do gênero Hylaeamys (Rodentia: Cricetidae) por citogenética clássica e molecular
(Universidade Federal do Pará, 2013-04-05) PINTO, Jamilly Amaral; NAGAMACHI, Cleusa Yoshiko; http://lattes.cnpq.br/8887641213110093
Rodents are one of the largest and oldest orders of the class Mammalia. In South America, the order Rodentia compromises about 42% of mammal species, and from this more than 50% belong to the family Cricetidae, which includes the subfamily Sigmodontinae. The genus Hylaeamys is inserted in the tribe Oryzomyini and corresponds to one of 10 new genera proposed for species and species groups within Oryzomys. Hylaeamys is the equivalent of "megacephalus group", and consists of the species H. acritus, H. laticeps, H. megacephalus, H. perenensis, H. oniscus, H. tatei and H. yunganus, distributed in Venezuela, Trinidad, Guyana, Paraguay and Brazil, in areas of the Amazon rain forest, Atlantic rainforest and savannah. This study aims to analyze chromosomal markers in two species of the genus Hylaeamys, providing data to assist in its taxonomic and cytogenetic characterization. Nineteen samples of Hylaeamys megacephalus (HME) and four samples of Hylaeamys oniscus (HON) were analyzed. HME has 2n = 54 and HON, 2n = 52. The results obtained by G- and C-banding and Fluorescent In Situ Hybridization with whole chromosome probes from Hylaeamys megacephalus made it possible to determine the chromosomal characteristics of the species studied, as well as allowing a comparative analysis between them, and in comparison with Cerradomys langguthi, observing homeologies and karyotypic differences. The two species of Hylaeamys differ by a centric fission/fusion rearrangement in which HON shows the association of the pairs 14/19 of HME. This association is shared with CLA with an inversion (19/14/19). This work is an achievement for phylogeny and chromosomal studies on the genus Hylaeamys.
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Caracterização cromossômica e mapeamento genômico comparativo de Oecomys paricola e Oecomys auyantepui com sondas de Hylaeamys megacephalus (Cricetidae – Sigmodontinae)
(Universidade Federal do Pará, 2015-05-19) ROSA, Celina Coelho da; NAGAMACHI, Cleusa Yoshiko; http://lattes.cnpq.br/8887641213110093
The Order Rodentia represents the largest mammal order, with approximately 42% of species currently known. Rodents have 2,227 species, 468 genera and 33 families recent, the latter being raised to 50 if the extinct families are considered. Their huge variation in morphology, diversity of habitats and climates and food are the causes of this be most numerous and evolutionarily successful among mammalian orders. The Oecomys genus belongs to the subfamily Sigmodontinae (Cricetidae, Rodentia) with approximately 16 described species, distributed in tropical and subtropical forest of Central and South America. Previous cytogenetic studies suggest that Oecomys features large karyotype diversity, with the diploid number ranging from 58 to 86. In this study were analyzed by conventional cytogenetic techniques and multidirectional chromosome painting (using whole chromosome probes of Hylaeamys megacephalus) 18 specimens of Oecomys were analyzed, four were collected in the metropolitan area of Belém, Pará; two in the city of Santa Barbara, Pará; five in the region of Carajás, Pará and 7 in Calha Norte region, Pará. Specimes from Belém Environmental Park had 2n = 72 and FN = 76; specimes from Santa Barbara had 2n = 70 and FN = 74; from Carajás presented 2n = 70 and FN = 72. All this sample was identified as O. paricola. Specimens collected from the Calha Norte region had 2n = 62 and NF = 80 and were identified as O. auyantepui. The cytotypes described for O. paricola showed differences in five HME peaks, indicating 3 associations for this species. O. auyantepui showed five associations. Chromosomal differences found for O. paricola from different geographic regions suggest that these cytotypes belong to cryptic species. We suggest that these populations of O. paricola are a complex of species where the chromosomal differentiation already happened but not the morphological and molecular ones.
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Estudos citogenéticos e moleculares nos gêneros Mesomys e Lonchothrix (Rodentia, Echimyidae, Eumysopinae)
(Universidade Federal do Pará, 2022-08-29) OLIVEIRA, Leony Dias de; SILVA, Willam Oliveira da; http://lattes.cnpq.br/0903402972891613; https://orcid.org/0000-0003-3125-1075; NAGAMACHI, Cleusa Yoshiko; http://lattes.cnpq.br/8887641213110093; https://orcid.org/0000-0003-1516-2734
The Echimyidae family is considered the most taxonomically diverse among South American hystricognathi rodents, comprising 25 genera and 93 species. The subfamily Eumysopinae is represented by nine genera, among which we highlight the arboreal genera Mesomys, which has four recognized species, and Lonchothrix described as monotypic (L. emiliae), both distributed in the Amazon. Morphological, molecular and chromosomal studies in the genera Mesomys and Lonchothrix have contributed to a better understanding of taxonomic design, phylogenetic relationships and karyotypic patterns. Recent molecular investigations have shown an as yet undescribed diversity, suggesting that these taxa are even more diverse than previously assumed. Furthermore, the limits of geographic distribution in the Amazon for the species M. hispidus and M. stimulax have been questioned by some authors. In this sense, the current study sought to investigate the karyotypic diversity and the geographic limits of the Mesomys and Lonchothrix genera, based on classical and molecular cytogenetic analysis and through sequences of the mitochondrial genes Cytochrome b (Cytb) and Cytochrome Oxidase - Subunit I (COI) from different locations in the Brazilian Amazon. The species M. stimulax and Mesomys sp. n. presented 2n=60/NF=110, while M. hispidus presented 2n=60/NF=112 and Lonchothrix emiliae presented 2n=66/NF=126, both unpublished karyotypes for the genera. Phylogenetic analysis confirmed Mesomys and Lonchothrix as sister genera and showed a high intraspecific rate in M. hispidus and Mesomys sp. n. from Itaituba, may be related to a new lineage in the genus Mesomys.
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Estudos citogenéticos em roedores do gênero oecomys (rodentia: cricetidae)
(Universidade Federal do Pará, 2011-04-29) ROSA, Celina Coelho da; NAGAMACHI, Cleusa Yoshiko; http://lattes.cnpq.br/8887641213110093
The rodents are one of the most diversified groups of living mammals and also have a large range of ecological adaptations. The rodents, because of yours population characteristics, developed as the most specious group of mammals in Neotropical forests and one of the most interesting for studies of genetic variation and evolution among vertebrates. The genus Oecomys (Sigmodontinae) comprises approximately 16 species that inhabit tropical and subtropical forests in Central and South America. Six of these species are expected to occur in eastern Brasilian Amazon. In literature, the genus Oecomys has a large karyotypic variation, where the diploid number ranges from 58 to 86. In this study specimens of Oecomys paricola Thomas, 1904 from Belém and Marajó Island, northern Brazil, were investigated using cytogenetic, molecular and morphological analyses. Three karyotypes were found, two from Belém (2n=68, FN=72 and 2n=70, FN=76) and a third from Marajó Island (2n=70, FN=72). No molecular or morphological differences were found between the individuals with differing cytotypes from Belém and Marajó Island. Specimens from the Belém City region may represent two cryptic species because two different karyotypes are present in the absence of significant differences in morphology and molecular characteristics. The Marajó Island and Belém populations represent distinct species that have been separated for some time, and are in the process of morphological and molecular differentiation as a consequence of reproductive isolation at the geographic and chromosomal levels.