Publications by authors named "Amanda Vidal"

The biodiversity crisis is a global phenomenon, and measures to monitor, stop, and revert the impacts on species' extinction risk are urgently needed. Megadiverse countries, especially in the Global South, are responsible for managing and protecting Earth's biodiversity. Various initiatives have started to sequence reference-level genomes or perform large-scale species detection and monitoring through environmental DNA.

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Increasing levels of industrialization have been associated with changes in gut microbiome structure and loss of features thought to be crucial for maintaining gut ecological balance. The stability of gut microbial communities over time within individuals seems to be largely affected by these changes but has been overlooked among transitioning populations from low- to middle-income countries. Here, we used metagenomic sequencing to characterize the temporal dynamics in gut microbiomes of 24 individuals living an urban non-industrialized lifestyle in the Brazilian Amazon.

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Article Synopsis
  • This study provides the complete mitochondrial genome (mitogenome) of the Brazilian Atlantic bushmaster snake (Lachesis), revealing details about its evolution.
  • The mitogenome is 17,177 base pairs long, containing genes for proteins, tRNAs, rRNAs, and control regions, with most genes encoded by the heavy-strand.
  • Phylogenetic analysis places Lachesis in the Crotalinae subfamily, closer to Agkistrodon, and supports a distinct classification among various snake families within Viperidae.
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Introduction: After three years since the beginning of the pandemic, the new coronavirus continues to raise several questions regarding its infectious process and host response. Several mutations occurred in different regions of the genome, such as in the spike gene, causing the emergence of variants of concern and interest (VOCs and VOIs), of which some present higher transmissibility and virulence, especially among patients with previous comorbidities. It is essential to understand its spread dynamics to prevent and control new biological threats that may occur in the future.

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Latin America is one of the regions in which the COVID-19 pandemic has a stronger impact, with more than 72 million reported infections and 1.6 million deaths until June 2022. Since this region is ecologically diverse and is affected by enormous social inequalities, efforts to identify genomic patterns of the circulating SARS-CoV-2 genotypes are necessary for the suitable management of the pandemic.

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Hereditary gastric cancers (HGCs) are supposed to be rare and difficult to identify. Nonetheless, many cases of young patients with gastric cancer (GC) fulfill the clinical criteria for considering this diagnosis but do not present the defined pathogenic mutations necessary to meet a formal diagnosis of HGC. Moreover, GC in young people is a challenging medical situation due to the usual aggressiveness of such cases and the potential risk for their relatives when related to a germline variant.

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Background: Considering the potential role of miRNAs as biomarkers and their interaction with both nuclear and mitochondrial genes, we investigated the miRNA expression profile in type 1 diabetes (T1DM) patients, including the pathways in which they are involved considering both nuclear and mitochondrial functions.

Methods: We analyzed samples of T1DM patients and control individuals (normal glucose tolerance) by high throughput miRNA sequencing (miRNome). Next, five miRNAs - , , , and were validated by RT-qPCR.

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Circular RNAs (circRNAs) are a class of long non-coding RNAs that have the ability to sponge RNA-Binding Proteins (RBPs). Triple-negative breast cancer (TNBC) has very aggressive behavior and poor prognosis for the patient. Here, we aimed to characterize the global expression profile of circRNAs in TNBC, in order to identify potential risk biomarkers.

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Gastric cancer (GC) is the fifth most common type of cancer and the third leading cause of cancer death in the world. It is a disease that encompasses a variety of molecular alterations, including in non-coding RNAs such as circular RNAs (circRNAs). In the present study, we investigated hsa_circ_0000211, hsa_circ_0000284, hsa_circ_0000524, hsa_circ_0001136 and hsa_circ_0004771 expression profiles using RT-qPCR in 71 gastric tissue samples from GC patients (tumor and tumor-adjacent samples) and volunteers without cancer.

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Background: Parkinson's disease (PD) is currently the second most common neurodegenerative disorder, burdening about 10 million elderly individuals worldwide. The multifactorial nature of PD poses a difficult obstacle for understanding the mechanisms involved in its onset and progression. Currently, diagnosis depends on the appearance of clinical signs, some of which are shared among various neurologic disorders, hindering early diagnosis.

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Parkinson's disease (PD) is the second-most common neurodegenerative disease, and its pathophysiology is associated with alpha-synuclein accumulation, oxidative stress, mitochondrial dysfunction, and neuroinflammation. MicroRNAs are small non-coding RNAs that regulate gene expression, and many previous studies have described their dysregulation in plasma, CSF, and in the brain of patients with PD. In this study, we aimed to provide a regulatory network analysis on differentially expressed miRNAs in the brain of patients with PD.

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The role of regulatory elements such as small ncRNAs and their mechanisms are poorly understood in infectious diseases. Tuberculosis is one of the oldest infectious diseases of humans and it is still a challenge to prevent and treat. Control of the infection, as well as its diagnosis, are still complex and current treatments used are linked to several side effects.

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Background: Next generation sequencing (NGS) has been a handy tool in clinical practice, mainly due to its efficiency and cost-effectiveness. It has been widely used in genetic diagnosis of several inherited diseases, and, in clinical oncology, it may enhance the discovery of new susceptibility genes and enable individualized care of cancer patients. In this context, we explored a pan-cancer panel in the investigation of germline variants in Brazilian patients presenting clinical criteria for hereditary cancer syndromes or familial history.

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Cervical cancer (CC) continues to be one of the leading causes of death for women across the world. Although it has been determined that papillomavirus infection is one of the main causes of the etiology of the disease, genetic and epigenetic factors are also required for its progression. Among the epigenetic factors are included the long noncoding RNAs (lncRNAs), transcripts of more than 200 nucleotides (nt) that generally do not code for proteins and have been associated with diverse functions such as the regulation of transcription, translation, RNA metabolism, as well as stem cell maintenance and differentiation, cell autophagy and apoptosis.

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Circular RNAs (circRNAs) are dysregulated in complex diseases, so we investigated their global expression profile in stroke. Public RNA-Seq data of human ischemic stroke lesion tissues and controls were used to perform the global expression analysis. Target RNA binding proteins and microRNAs were predicted .

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Article Synopsis
  • Studies on the peopling of South America have been limited by a lack of genetic data, particularly from Indigenous groups in the eastern Amazon.
  • Researchers analyzed the genetic variation of 58 Native American individuals from eight Amazonian populations to understand demographic patterns.
  • Findings reveal a clear genetic difference between Andean and Amazonian populations, supporting a migration theory involving movement along both the Pacific and Atlantic coasts, with southeastern South America populated by migrations from the north.
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The aberrant expression of microRNAs in known to play a crucial role in carcinogenesis. Here, we evaluated the miRNA expression profile of sigmoid colon cancer (SCC) compared to adjacent-to-tumor (ADJ) and sigmoid colon healthy (SCH) tissues obtained from colon biopsy extracted from Brazilian patients. Comparisons were performed between each group separately, considering as significant -values < 0.

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Mild cognitive impairment (MCI) and Alzheimer's Disease (AD) are complex diseases with their molecular architecture not elucidated. , Amyloid Beta Precursor Protein (), and Presenilin-1 () are well-known genes associated with both MCI and AD. Recently, epigenetic alterations and dysregulated regulatory elements, such as microRNAs (miRNAs), have been reported associated with neurodegeneration.

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  • The human genome contains genes that create both traditional mRNAs and a new type of RNA called circular RNAs (circRNAs) through different splicing processes.
  • A newly discovered subclass called read-through circRNAs (rt-circRNAs) includes coding regions from two neighboring genes, offering a unique perspective on gene expression.
  • The roles and effects of rt-circRNAs in the transcriptome are still being researched, but early findings suggest they provide valuable insights into the flexibility of RNA processing in cells.
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  • Leprosy, caused by Mycobacterium leprae, affects over 200,000 people annually, leading to nerve damage and disabilities, with symptoms appearing 3-7 years after infection.
  • Recent research discovered that most piRNAs, small noncoding RNAs involved in gene regulation, are downregulated in skin lesions of leprosy patients, which could link to various disease processes like apoptosis and neuropathic pain.
  • Understanding the role of piRNAs in leprosy may uncover new therapeutic targets to address nerve damage, as current treatments are lacking for this significant aspect of the disease.
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Circular RNAs (circRNAs) are a new class of long noncoding RNAs able to perform multiple functions, including sponging microRNAs (miRNAs) and RNA-Binding Proteins (RBPs). They play an important role in gastric carcinogenesis, but its involvement during gastric cancer (GC) development and progression are not well understood. We gathered miRNA and/or RBPs sponge circRNAs present in GC, and accessed their biological roles through functional enrichment of their target genes or ligand RBPs.

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Introduction: The nudix hydrolase 15 (NUDT15) gene acts in the metabolism of thiopurine, by catabolizing its active metabolite thioguanosine triphosphate into its inactivated form, thioguanosine monophosphate. The frequency of alternative NUDT15 alleles, in particular those that cause a drastic loss of gene function, varies widely among geographically distinct populations. In the general population of northern Brazilian, high toxicity rates (65%) have been recorded in patients treated with the standard protocol for acute lymphoblastic leukemia, which involves thiopurine-based drugs.

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Background: Gastric cancer is currently the third leading cause of cancer-related deaths worldwide, usually diagnosed at late stages. The development of new biomarkers to improve its prevention and patient management is critical for disease control. piRNAs are small regulatory RNAs important for gene silencing mechanisms, mainly associated with the silencing of transposable elements.

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  • - Mitochondria are essential organelles involved in energy production and programmed cell death, and they contain their own unique genetic material (mtDNA) distinct from nuclear DNA.
  • - Recent research shows that mtDNA is influenced by epigenetic factors like DNA methylation and non-coding RNAs (ncRNAs), leading to the emerging field of mitoepigenetics.
  • - The review discusses current knowledge on the role of ncRNAs in regulating mitochondrial functions and communication between the nucleus and mitochondria, highlighting gaps in understanding and future research directions.
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  • Mitochondria are crucial for cell function, and changes in their genetic material can lead to dysfunction and possibly cancer development, particularly gastric cancer (GC).
  • In a study of GC patients from the Amazon region, researchers found that tumor samples had significantly more genetic variants compared to both the internal controls (healthy tissue from the same patient) and external controls (healthy individuals).
  • The research also discovered that specific mitochondrial regions were more affected in tumors and highlighted a potential link between Native American ancestry and the risk of developing gastric cancer. It represents the first comprehensive analysis of mitochondrial genomes related to GC in Brazil.
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