Gabriel Peixoto - Academia.edu (original) (raw)

Papers by Gabriel Peixoto

ABSTRACTThe critical cellular transitions that govern human pancreas development are largely unkn... more ABSTRACTThe critical cellular transitions that govern human pancreas development are largely unknown. We performed large-scale single-cell RNA-sequencing (scRNA-Seq) to interrogate human fetal pancreas development from 8-20 weeks post conception. We identified 103 distinct cell types, including four novel endocrine progenitor subtypes displaying unique transcriptional features and differentiation potency. Integration with single-nucleus Assay for Transposase Accessible Chromatin Sequencing (snATAC-Seq) identified candidate regulators of human endocrine cell fate and revealed development-specific regulatory annotation at diabetes risk loci. Comparison of in vitro stem cell-derived and endogenous endocrine cells predicted aberrant genetic programs leading to the generation of off-target cells. Finally, knock-out studies revealed that the gene FEV regulates human endocrine differentiation. This work establishes a roadmap of human pancreatic development, highlights previously unapprecia...

Diabetes, 2019

Generation of functional beta cells for regenerative medicine would benefit from an increased und... more Generation of functional beta cells for regenerative medicine would benefit from an increased understanding of pancreatic endocrine cell differentiation. During pancreatic development, expression of Ngn3 defines the progenitor cells that will differentiate into one of five endocrine lineages, including the beta cell. Here, we identify and further characterize a distinct endocrine progenitor population defined by differential expression of a transcription factor named Fev in murine and human endocrine cell development. Using single-cell RNA-sequencing and genetic lineage tracing, we build a transcriptomic profile of murine Fev+ progenitors that is distinct from that of Ngn3+ progenitors and reconstruct lineage relationships among Ngn3+, Fev+, and differentiated, hormone+ cells. We further identify candidate transcriptional regulators along the differentiation trajectory of this Fev+ progenitor population toward the alpha or beta cell lineages. Translating our findings in murine pancr...

Journal of Fungi

The rubber tree, Hevea brasiliensis, is a neotropical Amazonian species. Despite its high economi... more The rubber tree, Hevea brasiliensis, is a neotropical Amazonian species. Despite its high economic value and fungi associated with native individuals, in its original area in Brazil, it has been scarcely investigated and only using culture-dependent methods. Herein, we integrated in silico approaches with novel field/experimental approaches and a case study of shotgun metagenomics and small RNA metatranscriptomics of an adult individual. Scientific literature, host fungus, and DNA databases are biased to fungal taxa, and are mainly related to rubber tree diseases and in non-native ecosystems. Metabarcoding retrieved specific phyllospheric core fungal communities of all individuals, adults, plantlets, and leaves of the same plant, unravelling hierarchical structured core mycobiomes. Basidiomycotan yeast-like fungi that display the potential to produce antifungal compounds and a complex of non-invasive ectophytic parasites (Sooty Blotch and Flyspeck fungi) co-occurred in all samples, ...

Research, Society and Development, 2021

As falhas congênitas são condições patológicas que são determinadas por fatores que surgem concom... more As falhas congênitas são condições patológicas que são determinadas por fatores que surgem concomitante ao nascimento, durante ou depois da concepção. No entanto, as anomalias também podem ser desenvolvidas por diversos fatores, idade materna, fatores ambientais, alterações do desenvolvimento dos tecidos e também por agentes infecciosos. As alterações congênitas podem estar associadas por uma variedade de fatores etiológicos. O estudo visa apresentar resultados encontrados na revisão integrativa qualitativa, que apresentem os fatores associados anomalias congênitas, expondo as diferentes vias as quais essas manifestações podem se desenvolver. A pesquisa trata-se de uma revisão integrativa da literatura do tipo qualitativa, a elaboração de levantamento metodológico para a pesquisa foi realizada no período Novembro de 2021, a base de dados utilizada foi Medical Literature Analysis and Retrieval System Online (MEDLINE) e Scientific Electronic Library Online (SCIELO). Utilizando o Medic...

International Journal of Health Science, 2021

Objective: To demonstrate the importance of complementary exams associated with the clinical pict... more Objective: To demonstrate the importance of complementary exams associated with the clinical picture for the diagnosis of Masked Hypertension (MH). Methods: This is a descriptive observational case-report study. Carried out through an outpatient consultation in a specialty office (Cardiology) in the city of Franca, São Paulo. For the description of the case, the primary source of data will be the patient's printed medical record, containing a detailed case history, description of the physical examination and complementary exams. Case details: Female patient, 69 years old, asymptomatic, presented with peak pressure and underwent control with residential measurements, also presenting alterations. It has other morbidities, such as dyslipidemia, diabetes and smoking, as well as a family history of coronary heart disease and heart disease, so it was indicated that other complementary exams such as MAP and ECHOCARDIOGRAM be performed. This diagnosis was possible due to the anatomical and functional changes that chronic hypertension causes, making it essential to carry out additional tests, as most of the time, diagnostic confirmation is delayed in association with functional consequences such as heart failure. Final considerations: it is concluded that the diagnosis of the pathology in question is essential to prevent damage and complications, in addition to helping to optimize the clinical treatment to achieve the desired therapeutic goals.

Research, Society and Development, 2022

O referido artigo trata-se de uma revisão bibliográfica sistemática realizada no período de 25 de... more O referido artigo trata-se de uma revisão bibliográfica sistemática realizada no período de 25 de outubro a 04 de novembro 2021 através de pesquisa eletrônica nas bases de dados do Google Acadêmico, Science Direct e PUBMED-NCBI-NIH para obtenção de dados mais recentes, a questão norteadora da pesquisa foi: Qual a importância dos canabinoides para o tratamento de fisiopatologias dermatológicas? Como critério de elegibilidade foi selecionado artigos dos últimos três anos referentes à cannabis, seus canabinoides e o tratamento de lesões dermatológicas. Os descritores utilizados foram: Cannabis, Skin Diseases e Cannabinoids verificados nos Descritores em Ciência da Saúde (DeCS) e no Medical Subject Headings (MeSH). Sucedeu-se o cruzamento utilizando- se do operador booleano AND: “Cannabis” AND “Skindiseases” AND “Cannabinoids”. Foram eleitos 9 artigos, ambos analisados de forma qualitativa, através de leitura metodológica. Mesmo que a erva medicinal seja conhecida por seu uso psicológic...

Mitochondrion, 2021

The mitochondrion is an organelle found in eukaryote organisms, and it is vital for different cel... more The mitochondrion is an organelle found in eukaryote organisms, and it is vital for different cellular pathways. The mitochondrion has its own DNA molecule and, because its genetic content is relatively conserved, despite the variation of size and structure, mitogenome sequences have been widely used as a promising molecular biomarker for taxonomy and evolution in fungi. In this study, the mitogenomes of two fungal species of Agaricomycetes class, Phellinotus piptadeniae and Trametes villosa, were assembled and annotated for the first time. We used these newly sequenced mitogenomes for comparative analyses with other 55 mitogenomes of Agaricomycetes available in public databases. Mitochondrial DNA (mtDNA) size and content are highly variable and non-coding and intronic regions, homing endonucleases (HEGs), and unidentified ORFs (uORFs) significantly contribute to the total size of the mitogenome. Furthermore, accessory genes (most of them as HEGs) are shared between distantly related species, most likely as a consequence of horizontal gene transfer events. Conversely, uORFs are only shared between taxonomically related species, most probably as a result of vertical evolutionary inheritance. Additionally, codon usage varies among mitogenomes and the GC content of mitochondrial features may be used to distinguish coding from non-coding sequences. Our results also indicated that transposition events of mitochondrial genes to the nuclear genome are not common. Despite the variation of size and content of the mitogenomes, mitochondrial genes seemed to be reliable molecular markers in our time-divergence analysis, even though the nucleotide substitution rates of mitochondrial and nuclear genomes of fungi are quite different. We also showed that many events of mitochondrial gene shuffling probably happened amongst the Agaricomycetes during evolution, which created differences in the gene order among species, even those of the same genus. Altogether, our study revealed new information regarding evolutionary dynamics in Agaricomycetes.

BIOINFO - Revista Brasileira de Bioinformática e Biologia Computacional, 2021

evido ao advento da pandemia de COVID-19, eventos acadêmicos passaram a ocorrer em plataformas on... more evido ao advento da pandemia de COVID-19, eventos acadêmicos passaram a ocorrer em plataformas online. Entretanto, diferente dos eventos presenciais, eventos pela internet limitam a interação entre participantes. Aqui, é apresentada uma estratégia de gamificação usada para ampliar o engajamento dos participantes durante o I Workshop Online de Bioinformática (WOB20). A estratégia, denominada "Taça das Casas", consistiu em agrupar os participantes, com base em suas áreas de interesse, em quatro grupos distintos que competiram entre si. Dos 2727 inscritos no WOB20, 200 participantes se inscreveram nessa atividade interativa. A atividade consistia em responder uma série de perguntas referentes às palestras ocorridas durante os três dias de eventos. O grupo vencedor deveria acertar a maior quantidade de questões (outliers foram removidos). Os participantes puderam interagir com outros membros do grupo por meio de salas exclusivas de discussão. Ao fim, notou-se uma maior proporção média de mensagens ao vivo entre participantes do evento durante a competição. Isso pode indicar um aumento no engajamento e interação

Microorganisms, 2021

Sisal is a common name for different plant varieties in the genus Agave (especially Agave sisalan... more Sisal is a common name for different plant varieties in the genus Agave (especially Agave sisalana) used for high-quality natural leaf fiber extraction. Despite the economic value of these plants, we still lack information about the diversity of viruses (virome) in non-tequilana species from the genus Agave. In this work, by associating RNA and DNA deep sequencing we were able to identify 25 putative viral species infecting A. sisalana, A. fourcroydes, and Agave hybrid 11648, including one strain of Cowpea Mild Mottle Virus (CPMMV) and 24 elements likely representing new viruses. Phylogenetic analysis indicated they belong to at least six viral families: Alphaflexiviridae, Betaflexiviridae, Botourmiaviridae, Closteroviridae, Partitiviridae, Virgaviridae, and three distinct unclassified groups. We observed higher viral taxa richness in roots when compared to leaves and stems. Furthermore, leaves and stems are very similar diversity-wise, with a lower number of taxa and dominance of a...

PeerJ, 2020

The true myrtle, Myrtus communis, is a small perennial evergreen tree that occurs in Europe, Afri... more The true myrtle, Myrtus communis, is a small perennial evergreen tree that occurs in Europe, Africa, and Asia with a circum-Mediterranean geographic distribution. Unfortunately, the Mediterranean Forests, where M. communis occurs, are critically endangered and are currently restricted to small fragmented areas in protected conservation units. In the present work, we performed, for the first time, a metabarcoding study on the spatial variation of fungal community structure in the foliar endophytome of this endemic plant of the Mediterranean biome, using bipartite network analysis as a model. The local bipartite network of Myrtus communis individuals and their foliar endophytic fungi is very low connected, with low nestedness, and moderately high specialization and modularity. Similar network patterns were also retrieved in both culture-dependent and amplicon metagenomics of foliar endophytes in distinct arboreal hosts in varied biomes. Furthermore, the majority of putative fungal end...