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Geographic isolation and reduced population sizes can lead to local extinction, low efficacy of selection and decreased speciation. However, population differentiation is an essential step of biological diversification. In allopatric speciation, geographically isolated populations differentiate and persist until the evolution of reproductive isolation and ecological divergence completes the speciation process. Pitcairnia flammea allows us to study the evolutionary consequences of habitat fragmentation on naturally disjoint rock-outcrop species from the Brazilian Atlantic Rainforest (BAF). Our main results showed low-to-moderate genetic diversity within populations, and deep population structuring caused by limited gene flow, low connectivity, genetic drift and inbreeding of long-term isolation and persistence of rock-outcrop populations throughout Quaternary climatic oscillations. Bayesian phylogenetic and model-based clustering analyses found no clear northern and southern phylogeographic structure commonly reported for many BAF organisms. Although we found two main lineages diverging by ~2 Mya during the early Pleistocene, species' delimitation analysis assigned most of the populations as independent evolving entities, suggesting an important role of disjoint rock outcrops in promoting high endemism in this rich biome. Lastly, we detected limited gene flow in sympatric populations although some hybridization and introgression were observed, suggesting a continuous speciation process in this species complex. Our data not only inform us about the extensive differentiation and limited gene flow found among Pitcairnia flammea species complex, but they also contain information about the mechanisms that shape the genetic architecture of small and fragmented populations of isolated rock outcrop of recently radiated plants.

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A análise de microarranjo da linhagem celular K562 obtida de paciente com leucemia mielóide crônica em crise blástica e suas derivadas com o fenótipo de resistência a múltiplas drogas (MDR), Lucena 1 e FEPS, selecionadas pelas drogas vincristina e daunorrubicina, respectivamente, apresentou diferença de expressão em genes da via de sinalização de NOTCH. Esta via está associada a funções celulares como proliferação, diferenciação e apoptose, mecanismos que as linhagens MDR modularam para manter o fenótipo. Além disso, a daunorrubicina, droga de seleção para FEPS, é uma das drogas usadas no tratamento de Leucemia Mielóide Aguda (LMA). Desse modo, é possível que a análise de expressão de genes da via de NOTCH auxilie na determinação do prognóstico de pacientes diagnosticados com LMA associado à sobrevida global. Assim, os objetivos do estudo foram validar os resultados de microarranjo sobre a expressão heterogênea dos genes da via de NOTCH nas linhagens MDR e K562 e analisar o potencial desses genes como indicador de prognóstico por meio da avaliação da sobrevida global de pacientes diagnosticados com LMA. Essas análises foram conduzidas pela técnica de PCR quantitativo. Foram validadas a maior expressão dos genes NOTCH 2 e HEY 1 em Lucena 1 e FEPS, e a menor expressão do gene HES 1 em FEPS, em comparação com K562...

Microarray analysis of the K562 cell line derived from a chronic myeloid leukemia patient in blast crisis and its derivative cells carrying the multidrug resistance (MDR) phenotype, Lucena 1 and FEPS selected by vincristine and daunorubicin, respectively, showed differential gene expression of the NOTCH signaling pathway. This signaling pathway plays a role in cell proliferation, differentiation, and apoptosis, mechanisms that MDR cells modulated to maintain the phenotype. Besides that, daunorubicin, the FEPS-selection drug, is one of the drugs used in the treatment of Acute Myeloid Leukemia (AML). Therefore, it is possible that the analysis of gene expression of the NOTCH pathway may help on the determination of AML-diagnosed patient's prognosis associated to overall survival. Therefore, the goal were to validate the microarray data of the heterogeneous gene expression of the NOCTH pathway between the MDR cell lines and K562 and to analyze the potential of these genes as an indicator of prognosis by evaluating the overall survival of patients diagnosed with AML. Those analyzes were conducted by quantitative PCR technique. It was validated the overexpression of NOTCH 2 and HEY 1 in Lucena 1 and FEPS and downregulation of HES 1 in FEPS in comparison to K562. It was also observed differences not identified by microarray analyzes, like the overexpression of NOTCH 3 in Lucena 1 and overexpression of JAGGED 2 in FEPS in comparison to K562. In addition, it was observed that cell density in culture influence the expression of HEY 1 and HES 1 genes of the NOTCH pathway in the MDR cell lines...

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