Publications by authors named "Agenor Dos Santos Junior"

8 Publications

  • Page 1 of 1

Cerebrospinal fluid analysis of pregnant women at early stages of COVID-19.

Taiwan J Obstet Gynecol 2022 Jul 23;61(4):672-674. Epub 2022 May 23.

Department of Obstetrics and Gynecology, University of Brasília, Brasília, Brazil.

Objective: To determine the presence or absence of SARS-CoV-2 in the cerebrospinal fluid of pregnant women at early stages of COVID-19.

Materials And Methods: We conducted a prospective observational study with pregnant women undergoing cesarean section and real-time polymerase chain reaction to SARS-CoV-2 was performed in the cerebrospinal fluid in the early stages of COVID-19.

Results: Fourteen pregnant women, whose COVID-19 symptoms started between four to 18 days prior to delivery, were included. Eleven of the women reported anosmia, dysgeusia, and headaches and there were two fatal cases. SARS-Cov-2 was not present in the cerebrospinal fluid of these COVID-19 patients with early neurological symptoms, even in severe cases.

Conclusion: Our study suggests that peripheric cell damage and parainfectious phenomena may predominate over direct central nervous system injury in the pathophysiology of COVID-19 related early neurological symptoms on pregnant women.
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http://dx.doi.org/10.1016/j.tjog.2022.03.043DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9124920PMC
July 2022

Field and classroom initiatives for portable sequence-based monitoring of dengue virus in Brazil.

Nat Commun 2021 04 16;12(1):2296. Epub 2021 Apr 16.

Fundação Oswaldo Cruz, Bio-Manguinhos, Rio de Janeiro, Rio de Janeiro, Brazil.

Brazil experienced a large dengue virus (DENV) epidemic in 2019, highlighting a continuous struggle with effective control and public health preparedness. Using Oxford Nanopore sequencing, we led field and classroom initiatives for the monitoring of DENV in Brazil, generating 227 novel genome sequences of DENV1-2 from 85 municipalities (2015-2019). This equated to an over 50% increase in the number of DENV genomes from Brazil available in public databases. Using both phylogenetic and epidemiological models we retrospectively reconstructed the recent transmission history of DENV1-2. Phylogenetic analysis revealed complex patterns of transmission, with both lineage co-circulation and replacement. We identified two lineages within the DENV2 BR-4 clade, for which we estimated the effective reproduction number and pattern of seasonality. Overall, the surveillance outputs and training initiative described here serve as a proof-of-concept for the utility of real-time portable sequencing for research and local capacity building in the genomic surveillance of emerging viruses.
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http://dx.doi.org/10.1038/s41467-021-22607-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8052316PMC
April 2021

Figainin 1, a Novel Amphibian Skin Peptide with Antimicrobial and Antiproliferative Properties.

Antibiotics (Basel) 2020 Sep 21;9(9). Epub 2020 Sep 21.

Laboratory of Toxinology, Department of Physiological Sciences, Institute of Biology, University of Brasília, Brasília 70.910-900, DF, Brazil.

Amphibian skin secretions are abundant in bioactive compounds, especially antimicrobial peptides. These molecules are generally cationic and rich in hydrophobic amino acids, have an amphipathic structure and adopt an α-helical conformation when in contact with microorganisms membranes. In this work, we purified and characterized Figainin 1, a novel antimicrobial and antiproliferative peptide from the cutaneous secretion of the frog . Figainin 1 is a cationic peptide with eighteen amino acid residues-rich in leucine and isoleucine, with an amidated C-terminus-and adopts an α-helical conformation in the presence of trifluoroethanol (TFE). It displayed activity against Gram-negative and especially Gram-positive bacteria, with MIC values ranging from 2 to 16 µM, and showed an IC value of 15.9 µM against epimastigote forms of ; however, Figanin 1 did not show activity against species. This peptide also showed cytolytic effects against human erythrocytes with an HC of 10 µM, in addition to antiproliferative activity against cancer cells and murine fibroblasts, with IC values ranging from 10.5 to 13.7 µM. Despite its adverse effects on noncancerous cells, Figainin 1 exhibits interesting properties for the development of new anticancer agents and anti-infective drugs against pathogenic microorganisms.
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http://dx.doi.org/10.3390/antibiotics9090625DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7559428PMC
September 2020

Biological Properties of a Novel Multifunctional Host Defense Peptide from the Skin Secretion of the Chaco Tree Frog, .

Biomolecules 2020 05 20;10(5). Epub 2020 May 20.

Laboratory of Toxinology, Department of Physiological Sciences, Institute of Biology, University of Brasília, Brasília 70.910-900, Brazil.

In recent years, the number of new antimicrobial drugs launched on the market has decreased considerably even though there has been an increase in the number of resistant microbial strains. Thus, antimicrobial resistance has become a serious public health problem. Amphibian skin secretions are a rich source of host defense peptides, which generally are cationic and hydrophobic molecules, with a broad-spectrum of activity. In this study, one novel multifunctional defense peptide was isolated from the skin secretion of the Chaco tree frog, Figainin 2 (FLGAILKIGHALAKTVLPMVTNAFKPKQ) is cationic and hydrophobic, adopts an α-helical structure in 50% () trifluoroethanol (TFE), and is thermally stable. This peptide exhibited activity against Gram-negative and Gram-positive pathogenic bacteria arboviruses, epimastigotes; however, it did not show activity against yeasts. Figainin 2 also showed antiproliferative activity on cancer cells, is moderately active on human erythrocytes, and activates the oxidative burst in human neutrophils.
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http://dx.doi.org/10.3390/biom10050790DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7277517PMC
May 2020

Metabolic Peculiarities of Dimorphism as Demonstrated by iTRAQ Labeling Proteomics.

Front Microbiol 2019 20;10:555. Epub 2019 Mar 20.

Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Brazil.

Paracoccidioidomycosis (PCM), a systemic mycosis with a high incidence in Latin America, is caused by thermodimorphic fungi of the genus. The contact with host occurs by the inhalation of conidia or mycelial propagules which once reaching the pulmonary alveoli differentiate into yeast cells. This transition process is vital in the pathogenesis of PCM allowing the fungus survival in the host. Thus, the present work performed a comparative proteome analysis of mycelia, mycelia-to-yeast transition, and yeast cells of . For that, tryptic peptides were labeled with iTRAQ and identified by LC-MS/MS and computational data analysis, which allowed the identification of 312 proteins differentially expressed in different morphological stages. Data showed that yeast cells preferentially employ aerobic beta-oxidation and the tricarboxylic acid cycle accompanied by oxidative phosphorylation for ATP production, in comparison to mycelia and the transition from mycelia-to-yeast cells. Furthermore, yeast cells show a metabolic reprogramming in amino acid metabolism and in the induction of virulence determinants and heat shock proteins allowing adaptation to environmental conditions during the increase of the temperature. In opposite of that, the alcoholic fermentation found to , at least under laboratory conditions, is strongly favored in mycelium compared to yeast cells. Thereby, the data strongly support substantial metabolic differences among members of the complex, when comparing the saprobiotic mycelia and the yeast parasitic phases.
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http://dx.doi.org/10.3389/fmicb.2019.00555DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6436475PMC
March 2019

Sample Preparation of Trypanosoma cruzi Surface, Extracellular, and Nuclear Subproteomes.

Methods Mol Biol 2019 ;1955:77-87

Department of Cell Biology, Laboratory of Protein Chemistry and Biochemistry, University of Brasilia, Brasília, DF, Brazil.

The preparation of subproteome fractions prior to proteome analysis provides both the enrichment of proteins sub-represented in global proteome analysis and information on the cellular localization of the identified proteins. Here we describe protocols for the preparation of Trypanosoma cruzi surface and extracellular and nuclear fractions for further subproteome analysis.
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http://dx.doi.org/10.1007/978-1-4939-9148-8_6DOI Listing
July 2019

Proteome analysis of Phytomonas serpens, a phytoparasite of medical interest.

PLoS One 2018 10;13(10):e0204818. Epub 2018 Oct 10.

Laboratory of Gene Biology, Department of Cell Biology, University of Brasília, Brasília, Federal District, Brazil.

The protozoan Phytomonas serpens (class Kinetoplastea) is an important phytoparasite that has gained medical importance due to its similarities to Trypanosoma cruzi, the etiological agent of Chagas disease. The present work describes the first proteome analysis of P. serpens. The parasite was separated into cytosolic and high density organelle fractions, which, together with total cell extract, were subjected to LC-MS/MS analyses. Protein identification was conducted using a comprehensive database composed of genome sequences of other related kinetoplastids. A total of 1,540 protein groups were identified among the three sample fractions. Sequences from Phytomonas sp. in the database allowed the highest number of identifications, with T. cruzi and T. brucei the human pathogens providing the greatest contribution to the identifications. Based on the proteomics data obtained, we proposed a central metabolic map of P. serpens, which includes all enzymes of the citric acid cycle. Data also revealed a new range of proteins possibly responsible for immunological cross-reactivity between P. serpens and T. cruzi.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0204818PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6179244PMC
March 2019

Unveiling the Trypanosoma cruzi Nuclear Proteome.

PLoS One 2015 18;10(9):e0138667. Epub 2015 Sep 18.

Department of Cell Biology, Institute of Biology, University of Brasilia, Campus Darcy Ribeiro, Asa Norte, 70910-900, Brasília, Brazil.

Replication of Trypanosoma cruzi, the etiological agent of Chagas disease, displays peculiar features, such as absence of chromosome condensation and closed mitosis. Although previous proteome and subproteome analyses of T. cruzi have been carried out, the nuclear subproteome of this protozoan has not been described. Here, we report, for the first time to the best of our knowledge, the isolation and proteome analysis of T. cruzi nuclear fraction. For that, T. cruzi epimastigote cells were lysed and subjected to cell fractionation using two steps of sucrose density gradient centrifugation. The purity of the nuclear fraction was confirmed by phase contrast and fluorescence microscopy. Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) allowed the identification of 864 proteins. Among those, 272 proteins were annotated as putative uncharacterized, and 275 had not been previously reported on global T. cruzi proteome analysis. Additionally, to support our enrichment method, bioinformatics analysis in DAVID was carried out. It grouped the nuclear proteins in 65 gene clusters, wherein the clusters with the highest enrichment scores harbor members with chromatin organization and DNA binding functions.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0138667PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4575177PMC
May 2016
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