Author
Vasco Azevedo
Other affiliations: Institut national de la recherche agronomique, Federal University of Pará
Bio: Vasco Azevedo is an academic researcher from Universidade Federal de Minas Gerais. The author has contributed to research in topics: Corynebacterium pseudotuberculosis & Genome. The author has an hindex of 55, co-authored 558 publications receiving 15441 citations. Previous affiliations of Vasco Azevedo include Institut national de la recherche agronomique & Federal University of Pará.
Papers published on a yearly basis
Papers
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TL;DR: Bacillus subtilis is the best-characterized member of the Gram-positive bacteria, indicating that bacteriophage infection has played an important evolutionary role in horizontal gene transfer, in particular in the propagation of bacterial pathogenesis.
Abstract: Bacillus subtilis is the best-characterized member of the Gram-positive bacteria. Its genome of 4,214,810 base pairs comprises 4,100 protein-coding genes. Of these protein-coding genes, 53% are represented once, while a quarter of the genome corresponds to several gene families that have been greatly expanded by gene duplication, the largest family containing 77 putative ATP-binding transport proteins. In addition, a large proportion of the genetic capacity is devoted to the utilization of a variety of carbon sources, including many plant-derived molecules. The identification of five signal peptidase genes, as well as several genes for components of the secretion apparatus, is important given the capacity of Bacillus strains to secrete large amounts of industrially important enzymes. Many of the genes are involved in the synthesis of secondary metabolites, including antibiotics, that are more typically associated with Streptomyces species. The genome contains at least ten prophages or remnants of prophages, indicating that bacteriophage infection has played an important evolutionary role in horizontal gene transfer, in particular in the propagation of bacterial pathogenesis.
3,753 citations
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TL;DR: The current molecular strategies for the study of virulence in C. pseudotuberculosis are examined, including the latest research on the identification of novel virulence factors and genes, which will help to better understand the biology of this microorganism.
Abstract: Corynebacterium pseudotuberculosis is the etiological agent of caseous lymphadenitis (CLA), a common disease in small ruminant populations throughout the world. Once established, this disease is difficult to eradicate because drug therapy is not effective and because the clinical detection of infected animals is of limited efficiency. We reviewed the microbiological, biochemical and taxonomic features of C. pseudotuberculosis, general aspects of infection, the main virulence determinants and currently available commercial vaccines. We also examined the current molecular strategies for the study of virulence in C. pseudotuberculosis, including the latest research on the identification of novel virulence factors and genes, which will help us to better understand the biology of this microorganism. This knowledge may also contribute to the development of improved CLA vaccines, including subunit and DNA-based types, as well as to improve the diagnosis, treatment and control of this disease.
340 citations
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Universidade Federal do Rio Grande do Sul1, Pontifícia Universidade Católica do Rio Grande do Sul2, Federal University of Rio de Janeiro3, University of São Paulo4, Federal University of Amazonas5, Universidade Federal de Minas Gerais6, University of Brasília7, State University of Campinas8, Empresa Brasileira de Pesquisa Agropecuária9, Ludwig Institute for Cancer Research10, Federal University of Pará11, State University of Santa Cruz12, Universidade Católica de Brasília13, Universidade Federal de Pelotas14, Universidade Federal de Santa Catarina15, Concordia University Wisconsin16, Universidade Federal Rural de Pernambuco17, Federal University of Ceará18, Federal University of Rio Grande do Norte19, National Institute of Amazonian Research20, Universidade Federal de Santa Maria21, Pontifícia Universidade Católica do Paraná22, Federal University of Alagoas23, Federal University of Paraná24, Universidade Federal de Goiás25
TL;DR: Genomic comparisons revealed that reduction in genome size implied loss of redundant metabolic pathways, with maintenance of alternative routes in different species, and indicated a likely transfer event of hemagglutinin-coding DNA sequences from M. gallisepticum to M. synoviae.
Abstract: This work reports the results of analyses of three complete mycoplasma genomes, a pathogenic (7448) and a nonpathogenic (J) strain of the swine pathogen Mycoplasma hyopneumoniae and a strain of the avian pathogen Mycoplasma synoviae; the genome sizes of the three strains were 920,079 bp, 897,405 bp, and 799,476 bp, respectively. These genomes were compared with other sequenced mycoplasma genomes reported in the literature to examine several aspects of mycoplasma evolution. Strain-specific regions, including integrative and conjugal elements, and genome rearrangements and alterations in adhesin sequences were observed in the M. hyopneumoniae strains, and all of these were potentially related to pathogenicity. Genomic comparisons revealed that reduction in genome size implied loss of redundant metabolic pathways, with maintenance of alternative routes in different species. Horizontal gene transfer was consistently observed between M. synoviae and Mycoplasma gallisepticum. Our analyses indicated a likely transfer event of hemagglutinin-coding DNA sequences from M. gallisepticum to M. synoviae.
314 citations
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Empresa Brasileira de Pesquisa Agropecuária1, Universidade Federal de Santa Catarina2, University of São Paulo3, National Institute of Amazonian Research4, Universidade Federal de Minas Gerais5, Federal University of Rio de Janeiro6, Federal University of Rio Grande do Norte7, University of Brasília8, Universidade Federal de Goiás9, Universidade Católica de Brasília10, Pontifícia Universidade Católica do Rio Grande do Sul11, Ludwig Institute for Cancer Research12, State University of Santa Cruz13, Federal University of Ceará14, State University of Campinas15, Sao Paulo State University16, Federal University of Pernambuco17, Pontifícia Universidade Católica do Paraná18, Federal University of Paraná19, Universidade Federal do Rio Grande do Sul20, Federal University of Alagoas21, Federal University of Pará22
TL;DR: The complete genome sequence reveals extensive alternative pathways for energy generation, complex and extensive systems for stress adaptation and motility, and widespread utilization of quorum sensing for control of inducible systems, all of which underpin the versatility and adaptability of the organism.
Abstract: Chromobacterium violaceum is one of millions of species of free-living microorganisms that populate the soil and water in the extant areas of tropical biodiversity around the world. Its complete genome sequence reveals (i) extensive alternative pathways for energy generation, (ii) ≈500 ORFs for transport-related proteins, (iii) complex and extensive systems for stress adaptation and motility, and (iv) widespread utilization of quorum sensing for control of inducible systems, all of which underpin the versatility and adaptability of the organism. The genome also contains extensive but incomplete arrays of ORFs coding for proteins associated with mammalian pathogenicity, possibly involved in the occasional but often fatal cases of human C. violaceum infection. There is, in addition, a series of previously unknown but important enzymes and secondary metabolites including paraquat-inducible proteins, drug and heavy-metal-resistance proteins, multiple chitinases, and proteins for the detoxification of xenobiotics that may have biotechnological applications.
299 citations
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TL;DR: The results suggest that some F. prausnitzii strains could represent good candidates as next-generation probiotic as well as a deep molecular and metabolic characterization of these isolated strains.
Abstract: Faecalibacterium prausnitzii is a major member of the Firmicutes phylum and one of the most abundant bacteria in the healthy human microbiota. F. prausnitzii depletion has been reported in several intestinal disorders, and more consistently in Crohn’s disease (CD) patients. Despite its importance in human health, only few microbiological studies have been performed to isolate novel F. prausnitzii strains in order to better understand the biodiversity and physiological diversity of this beneficial commensal species. In this study, we described a protocol to isolate novel F. prausnitzii strains from feces of healthy volunteers as well as a deep molecular and metabolic characterization of these isolated strains. These F. prausnitzii strains were classified in two phylogroups and 3 clusters according to 16S rRNA sequences and results support that they would belong to two different genomospecies or genomovars as no genome sequencing has been performed in this work. Differences in enzymes production, antibiotic resistance and immunomodulatory properties were found to be strain-dependent. So far, all F. prausnitzii isolates share some characteristic such as i) the lack of epithelial cells adhesion, plasmids, anti-microbial and hemolytic activity and ii) the presence of DNAse activity. Furthermore, Short Chain Fatty Acids (SCFA) production was assessed for the novel isolates as these products influence intestinal homeostasis. Indeed, the butyrate production has been correlated to the capacity to induce IL-10, an anti-inflammatory cytokine, in peripheral blood mononuclear cells (PBMC) but not to the ability to block IL-8 secretion in TNF-α-stimulated HT-29 cells, reinforcing the hypothesis of a complex anti-inflammatory pathway driven by F. prausnitzii. Altogether, our results suggest that some F. prausnitzii strains could represent good candidates as next-generation probiotic.
274 citations
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28,685 citations
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TL;DR: Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols used xiii 1.
Abstract: Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols Used xiii 1. The Importance of Islands 3 2. Area and Number of Speicies 8 3. Further Explanations of the Area-Diversity Pattern 19 4. The Strategy of Colonization 68 5. Invasibility and the Variable Niche 94 6. Stepping Stones and Biotic Exchange 123 7. Evolutionary Changes Following Colonization 145 8. Prospect 181 Glossary 185 References 193 Index 201
14,171 citations
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TL;DR: It is suggested that the natural selection against large insertion/deletion is so weak that a large amount of variation is maintained in a population.
11,521 citations
01 Jan 2006
TL;DR: Probability distributions of linear models for regression and classification are given in this article, along with a discussion of combining models and combining models in the context of machine learning and classification.
Abstract: Probability Distributions.- Linear Models for Regression.- Linear Models for Classification.- Neural Networks.- Kernel Methods.- Sparse Kernel Machines.- Graphical Models.- Mixture Models and EM.- Approximate Inference.- Sampling Methods.- Continuous Latent Variables.- Sequential Data.- Combining Models.
10,141 citations
01 Jun 2012
TL;DR: SPAdes as mentioned in this paper is a new assembler for both single-cell and standard (multicell) assembly, and demonstrate that it improves on the recently released E+V-SC assembler and on popular assemblers Velvet and SoapDeNovo (for multicell data).
Abstract: The lion's share of bacteria in various environments cannot be cloned in the laboratory and thus cannot be sequenced using existing technologies. A major goal of single-cell genomics is to complement gene-centric metagenomic data with whole-genome assemblies of uncultivated organisms. Assembly of single-cell data is challenging because of highly non-uniform read coverage as well as elevated levels of sequencing errors and chimeric reads. We describe SPAdes, a new assembler for both single-cell and standard (multicell) assembly, and demonstrate that it improves on the recently released E+V-SC assembler (specialized for single-cell data) and on popular assemblers Velvet and SoapDeNovo (for multicell data). SPAdes generates single-cell assemblies, providing information about genomes of uncultivatable bacteria that vastly exceeds what may be obtained via traditional metagenomics studies. SPAdes is available online ( http://bioinf.spbau.ru/spades ). It is distributed as open source software.
10,124 citations