Biology subjects

Moreira, R. G.

Publications and source records attributed to Moreira, R. G..

3 recordsLinked to original sources

bioRxiv2025

The peptide LyeTx I mnΔK induces transcriptomic reprogramming in a novel Multidrug-resistant Acinetobacter baumannii

Acinetobacter baumannii is a critical pathogen in healthcare-associated infections, and treatment is challenging due to the emergence of multidrug-resistant strains. Antimicrobial peptides, such as LyeTx I mn{Delta}K, a synthetic peptide derived of a toxin from the spider Lycosa erythrognatha, represent a promising alternative due to their broad-spectrum activity and synergistic potential with antibiotics like meropenem. This study aimed to compare the genomes of several A. baumannii strains, including a novel multidrug-resistant A. baumannii isolate (AC37), and to evaluate the antimicrobial effects of LyeTx I mn{Delta}K-alone and in combination with meropenem-through transcriptomic analysis. Genome assembly and annotation of AC37 revealed 31 antibiotic resistance genes, and phylogenetic analysis comprising 123 A. baumannii genomes, including the reference strain, identified three unique resistant genes in the AC37 strain. Mobilome analysis showed 13 genes associated with mobile genetic elements, including two of the unique genes, highlighting horizontal gene transfer events. Transcriptomic profiling revealed that treatment with LyeTx I mn{Delta}K peptide alone induced several differentially expressed genes, including two efflux pump operons. Additionally, pathways related to protein synthesis, export, and secretion were activated, indicating a broader cellular response to the peptide. The treatment with LyeTx I mn{Delta}K in combination with meropenem disrupted oxidative phosphorylation, further revealing the metabolic plasticity of the bacterial response to external stresses. This study characterizes a new A. baumannii isolate and provides new insights into the bacterial response to a potential novel therapeutic molecule.

bioinformatics↗

bioRxiv2020

De novo transcriptome assembly and functional annotation of cobia (Rachycentron canadum): molecular approach as a base to nutritional studies

Cobia (Rachycentron canadum) is a marine teleost species with great productive potential worldwide. However, the genomic information currently available for this species in public databases is limited. Such lack of information hinders gene expression assessments that might bring forward novel insights into the physiology, ecology, evolution, and genetics of this potential aquaculture species. In this study, we report the first de novo transcriptome assembly of R. canadum liver, improving the availability of novel gene sequences for this species. Illumina sequencing of liver transcripts generated 1,761,965,794 raw reads, which were filtered into 1,652,319,304 high-quality reads. De novo assembly resulted in 101,789 unigenes and 163,096 isoforms, with an average length of 950.61 and 1,617.34 nt, respectively. Moreover, we found that 126,013 of these transcripts bear potentially coding sequences, and 125,993 of these elements (77.3%) correspond to functionally annotated genes found in six different databases. We also identified 701 putative ncRNA and 35,414 putative lncRNA. Interestingly, homologues for 410 of these putative lncRNAs have already been observed in previous analyzes with Danio rerio, Lates calcarifer, Seriola lalandi dorsalis, Seriola dumerili or Echeneis naucrates. Finally, we identified 7,894 microsatellites related to cobias putative lncRNAs. Thus, the information derived from the transcriptome assembly described herein will likely assist future nutrigenomics and breeding programs involving this important fish farming species.

bioinformatics↗

bioRxiv2019

Origins, admixture dynamics and homogenization of the African gene pool in the Americas

The Transatlantic Slave Trade transported more than 9 million Africans to the Americas between the early 16th and the mid-19th centuries. We performed genome-wide analysis of 6,267 individuals from 22 populations and observed an enrichment in West-African ancestry in northern latitudes of the Americas, whereas South/East African ancestry is more prevalent in southern South-America. This pattern results from distinct geographic and geopolitical factors leading to population differentiation. However, we observed a decrease of 68% in the African gene pool between-population diversity within the Americas when compared to the regions of origin from Africa, underscoring the importance of historical factors favoring admixture between individuals with different African origins in the New World. This is consistent with the excess of West-Central Africa ancestry (the most prevalent in the Americas) in the US and Southeast-Brazil, respect to historical-demography expectations. Also, in most of the Americas, admixture intensification occurred between 1,750 and 1,850, which correlates strongly with the peak of arrivals from Africa. This study contributes with a population genetics perspective to the ongoing social, cultural and political debate regarding ancestry, race, and admixture in the Americas.\n\nSignificance StatementDifferently from most genetic studies, that have estimated the overall African ancestry in the Americas, we perform a finer geographic analysis and infer how different African groups contributed to North-, South-American and Caribbean populations, in the context of geographic and geopolitical factors. We also perform a formal comparison of information from demographic history records of the Transatlantic Slave Trade with inferences based on genomic diversity of current populations. Our approach reveals the distinct regional African ancestry roots of different populations from North-, South-America and the Caribe and other important aspects of the historical process of mestizaje and its dynamics in the American continent.

genetics↗