Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 46
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
RNA ; 27(10): 1127-1139, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34253685

RESUMO

Comprehensive characterization of differentially spliced RNA transcripts with nanopore sequencing is limited by bioinformatics tools that are reliant on existing annotations. We have developed FLAME, a bioinformatics pipeline for alternative splicing analysis of gene-specific or transcriptome-wide long-read sequencing data. FLAME is a Python-based tool aimed at providing comprehensible quantification of full-length splice variants, reliable de novo recognition of splice sites and exons, and representation of consecutive exon connectivity in the form of a weighted adjacency matrix. Notably, this workflow circumvents issues related to inadequate reference annotations and allows for incorporation of short-read sequencing data to improve the confidence of nanopore sequencing reads. In this study, the Epstein-Barr virus long noncoding RNA RPMS1 was used to demonstrate the utility of the pipeline. RPMS1 is ubiquitously expressed in Epstein-Barr virus associated cancer and known to undergo ample differential splicing. To fully resolve the RPMS1 spliceome, we combined gene-specific nanopore sequencing reads from a primary gastric adenocarcinoma and a nasopharyngeal carcinoma cell line with matched publicly available short-read sequencing data sets. All previously reported splice variants, including putative ORFs, were detected using FLAME. In addition, 32 novel exons, including two intron retentions and a cassette exon, were discovered within the RPMS1 gene.


Assuntos
Infecções por Vírus Epstein-Barr/genética , Herpesvirus Humano 4/genética , Carcinoma Nasofaríngeo/genética , Neoplasias Nasofaríngeas/genética , Splicing de RNA , RNA Longo não Codificante/genética , RNA Mensageiro/genética , Software , Benchmarking , Linhagem Celular Tumoral , Biologia Computacional/métodos , Infecções por Vírus Epstein-Barr/metabolismo , Infecções por Vírus Epstein-Barr/patologia , Infecções por Vírus Epstein-Barr/virologia , Éxons , Herpesvirus Humano 4/patogenicidade , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Íntrons , Sequenciamento por Nanoporos , Carcinoma Nasofaríngeo/metabolismo , Carcinoma Nasofaríngeo/patologia , Carcinoma Nasofaríngeo/virologia , Neoplasias Nasofaríngeas/metabolismo , Neoplasias Nasofaríngeas/patologia , Neoplasias Nasofaríngeas/virologia , RNA Longo não Codificante/metabolismo , RNA Mensageiro/metabolismo , RNA Viral/genética , RNA Viral/metabolismo , Análise de Sequência de RNA
2.
Artigo em Inglês | MEDLINE | ID: mdl-37083582

RESUMO

Two bacterial strains, SP1W3T and SP1S2-7T, were isolated from samples of water and sediments collected in Vaxholm, a town located on the Stockholm archipelago in the Baltic Sea, in November 2021. The strains were identified as novel genomic species within the genus Shewanella, based upon comparative analysis of whole genome sequence data. Strain SP1W3T (genome size, 5.20 Mbp; G+C content, 46.0 mol%), isolated from water, was determined to be most closely related to S. hafniensis ATCC-BAA 1207T and S. baltica NCTC 10735T, with digital DNA-DNA hybridization (dDDH) values of 61.7% and 60.4 %, respectively. Strain SP1S2-7T (genome size, 4.26 Mbp; G+C content, 41.5 mol%), isolated from sediments, was observed to be most closely related to S. aestuarii JCM17801T, with a pairwise dDDH value of 33.8 %. Polyphasic analyses of physiological and phenotypic characteristics, in addition to genomic analyses, confirmed that each of these two strains represent distinct, novel species within the genus Shewanella, for which the names Shewanella septentrionalis sp. nov. (type strain SP1W3T=CCUG 76164T=CECT 30651T) and Shewanella holmiensis sp. nov. (type strain SP1S2-7T=CCUG 76165T=CECT 30652T) are proposed.


Assuntos
Shewanella , Shewanella/genética , Ácidos Graxos/química , Análise de Sequência de DNA , Composição de Bases , DNA Bacteriano/genética , RNA Ribossômico 16S/genética , Filogenia , Técnicas de Tipagem Bacteriana , Água do Mar/microbiologia , Água
3.
Proc Natl Acad Sci U S A ; 117(49): 31519-31526, 2020 12 08.
Artigo em Inglês | MEDLINE | ID: mdl-33203681

RESUMO

Genome-wide epistasis analysis is a powerful tool to infer gene interactions, which can guide drug and vaccine development and lead to deeper understanding of microbial pathogenesis. We have considered all complete severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genomes deposited in the Global Initiative on Sharing All Influenza Data (GISAID) repository until four different cutoff dates, and used direct coupling analysis together with an assumption of quasi-linkage equilibrium to infer epistatic contributions to fitness from polymorphic loci. We find eight interactions, of which three are between pairs where one locus lies in gene ORF3a, both loci holding nonsynonymous mutations. We also find interactions between two loci in gene nsp13, both holding nonsynonymous mutations, and four interactions involving one locus holding a synonymous mutation. Altogether, we infer interactions between loci in viral genes ORF3a and nsp2, nsp12, and nsp6, between ORF8 and nsp4, and between loci in genes nsp2, nsp13, and nsp14. The paper opens the prospect to use prominent epistatically linked pairs as a starting point to search for combinatorial weaknesses of recombinant viral pathogens.


Assuntos
Epistasia Genética/genética , Genes Virais/genética , SARS-CoV-2/genética , COVID-19/patologia , Proteínas do Nucleocapsídeo de Coronavírus/genética , RNA-Polimerase RNA-Dependente de Coronavírus/genética , Exorribonucleases/genética , Genoma Viral/genética , Humanos , Metiltransferases/genética , RNA Helicases/genética , Seleção Genética/genética , Proteínas não Estruturais Virais/genética , Proteínas Virais/genética , Proteínas Viroporinas/genética
4.
Artigo em Inglês | MEDLINE | ID: mdl-35819404

RESUMO

A Gram-negative rod with a single polar flagellum was isolated from a freshwater reservoir used for household purposes in Boane District, near Maputo, Mozambique, and designated as strain DB1T. Growth was observed at 30-42 °C (optimum, 30-37 °C) and with 0.5-1.5 % NaCl. Whole-genome-, rpoD- and 16S rRNA-based phylogenies revealed this isolate to be distant from other Pseudomonas species with Pseudomonas resinovorans, Pseudomonas furukawaii and Pseudomonas lalkuanensis being the closest relatives. Phenotypic analyses of strain DB1T showed marked differences with respect to type strains P. resinovorans CCUG 2473T, P. lalkuanensis CCUG 73691T, P. furukawaii CCUG 75672T and Pseudomonas otiditis CCUG 55592T. Taken together, our results indicate that strain DB1T is a representative of a novel species within the genus Pseudomonas for which the name Pseudomonas boanensis is proposed. The type strain is DB1T (=CCUG 62977T=CECT 30359T).


Assuntos
Ácidos Graxos , Rios , Bactérias , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Moçambique , Hibridização de Ácido Nucleico , Filogenia , Pseudomonas , RNA Ribossômico 16S/genética , Rios/microbiologia , Análise de Sequência de DNA , Água
5.
Int J Mol Sci ; 23(8)2022 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-35457143

RESUMO

One of the most important bacterial diseases in salmonid aquaculture is furunculosis, caused by Aeromonas salmonicida. Bacterial communication through secreted autoinducer signals, quorum sensing, takes part in the regulation of gene expression in bacteria, influencing growth and virulence. The skin and mucosal surfaces, covered by a mucus layer, are the first point of contact between fish and bacteria. Mucins are highly glycosylated and are the main components of mucus. Here, we validate the Vibrio harveyi BB170 bioreporter assay for quantifying A. salmonicida quorum sensing and study the effects of Atlantic salmon mucins as well as mono- and disaccharides on the AI-2 levels of A. salmonicida. Atlantic salmon mucins from skin, pyloric ceca, proximal and distal intestine reduced A. salmonicida AI-2 levels. Among the saccharides abundant on mucins, fucose, N-acetylneuraminic acid and GlcNAcß1-3Gal inhibited AI-2 A. salmonicida secretion. Removal of N-acetylneuraminic acid, which is the most abundant terminal residue on mucin glycans on Atlantic salmon mucins, attenuated the inhibitory effects on AI-2 levels of A. salmonicida. Deletion of A. salmonicida luxS abolished AI-2 production. In conclusion, Atlantic salmon mucins regulate A. salmonicida quorum sensing in a luxS and N-acetylneuraminic acid-dependent manner.


Assuntos
Aeromonas salmonicida , Salmo salar , Aeromonas salmonicida/metabolismo , Animais , Proteínas de Bactérias/genética , Mucinas/metabolismo , Ácido N-Acetilneuramínico , Percepção de Quorum , Salmo salar/metabolismo
6.
Int J Syst Evol Microbiol ; 70(8): 4544-4554, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32618559

RESUMO

The taxonomic status of six strains of Acinetobacter obtained from meat samples, collected from supermarkets in Porto, Portugal, was investigated using polyphasic analysis. Partial rpoB sequence similarities lower than 95 % to other Acinetobacter species with validly published names led to the hypothesis that these strains represented novel species. This was confirmed based on comparative multilocus sequence analysis, which included the gyrB, recA and 16S rRNA genes, revealing that these strains represented two coherent lineages that were distinct from each other and from all known species. The names Acinetobacter portensis sp. nov. (comprising four strains) and Acinetobacter guerrae sp. nov. (comprising two strains) are proposed for these novel species. The species status of these two groups was confirmed by low (below 95 %) whole-genome sequence average nucleotide identity values and low (below 70 %) digital DNA-DNA hybridization similarities between the whole-genome sequences of the proposed type strains of each novel species and the representatives of the known Acinetobacter species. Phylogenomic treeing from core genome analysis supported these results. The coherence of each new species lineage was supported by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry differentiation of the species at the protein level, by cellular fatty acid profiles, and by unique and differential combinations of metabolic and physiological properties shared by each novel species. The type strain of A. portensis sp. nov. is AC 877T (=CCUG 68672T=CCM 8789T) and the type strain of A. guerrae sp. nov. is AC 1271T (=CCUG 68674T=CCM 8791T).


Assuntos
Acinetobacter/classificação , Microbiologia de Alimentos , Carne/microbiologia , Filogenia , Acinetobacter/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Genes Bacterianos , Tipagem de Sequências Multilocus , Hibridização de Ácido Nucleico , Portugal , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
7.
PLoS Genet ; 13(2): e1006546, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-28231283

RESUMO

For the last 500 years, the Americas have been a melting pot both for genetically diverse humans and for the pathogenic and commensal organisms associated with them. One such organism is the stomach-dwelling bacterium Helicobacter pylori, which is highly prevalent in Latin America where it is a major current public health challenge because of its strong association with gastric cancer. By analyzing the genome sequence of H. pylori isolated in North, Central and South America, we found evidence for admixture between H. pylori of European and African origin throughout the Americas, without substantial input from pre-Columbian (hspAmerind) bacteria. In the US, strains of African and European origin have remained genetically distinct, while in Colombia and Nicaragua, bottlenecks and rampant genetic exchange amongst isolates have led to the formation of national gene pools. We found three outer membrane proteins with atypical levels of Asian ancestry in American strains, as well as alleles that were nearly fixed specifically in South American isolates, suggesting a role for the ethnic makeup of hosts in the colonization of incoming strains. Our results show that new H. pylori subpopulations can rapidly arise, spread and adapt during times of demographic flux, and suggest that differences in transmission ecology between high and low prevalence areas may substantially affect the composition of bacterial populations.


Assuntos
Infecções por Helicobacter/genética , Helicobacter pylori/genética , Filogenia , Neoplasias Gástricas/genética , Alelos , DNA Mitocondrial/genética , Evolução Molecular , Genoma Bacteriano , Infecções por Helicobacter/epidemiologia , Helicobacter pylori/patogenicidade , Humanos , Indígenas Norte-Americanos , América Latina , Neoplasias Gástricas/epidemiologia , Neoplasias Gástricas/microbiologia , População Branca
9.
J Bacteriol ; 201(21)2019 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-31405919

RESUMO

Colonic spirochetosis, diagnosed based on the striking appearance in histological sections, still has an obscure clinical relevance, and only a few bacterial isolates from this condition have been characterized to date. In a randomized, population-based study in Stockholm, Sweden, 745 healthy individuals underwent colonoscopy with biopsy sampling. Of these individuals, 17 (2.3%) had colonic spirochetosis, which was associated with eosinophilic infiltration and a 3-fold-increased risk for irritable bowel syndrome (IBS). We aimed to culture the bacteria and perform whole-genome sequencing of the isolates from this unique representative population sample. From 14 out of 17 individuals with spirochetosis we successfully isolated, cultured, and performed whole-genome sequencing of in total 17 isolates, including the Brachyspira aalborgi type strain, 513A. Also, 16S analysis of the mucosa-associated microbiota was performed in the cases and nonspirochetosis controls. We found one isolate to be of the species Brachyspira pilosicoli; all remaining isolates were of the species Brachyspira aalborgi Besides displaying extensive genetic heterogeneity, the isolates harbored several mucin-degrading enzymes and other virulence-associated genes that could confer a pathogenic potential in the human colon. We also showed that 16S amplicon sequencing using standard primers for human microbiota studies failed to detect Brachyspira due to primer incompatibility.IMPORTANCE This is the first report of whole-genome analysis of clinical isolates from individuals with colonic spirochetosis. This characterization provides new opportunities in understanding the physiology and potentials of these bacteria that densely colonize the gut in the individuals infected. The observation that standard 16S amplicon primers fail to detect colonic spirochetosis may have major implications for studies searching for associations between members of the microbiota and clinical conditions such as irritable bowel syndrome (IBS) and should be taken into consideration in project design and interpretation of gastrointestinal tract microbiota in population-based and clinical settings.


Assuntos
Brachyspira/isolamento & purificação , Colo/microbiologia , Infecções por Spirochaetales/microbiologia , Brachyspira/genética , Genômica/métodos , Humanos , Microbiota/genética , RNA Ribossômico 16S/genética
10.
Artigo em Inglês | MEDLINE | ID: mdl-31235629

RESUMO

Antibiotic resistance in bacteria is an emerging problem globally. Resistant bacteria are found in human and animal microbiota, as well as in the environment. Wastewater receives bacteria from all these sources and thus can provide a measurement of abundance and diversity of antibiotic-resistant bacteria circulating in communities. In this study, water samples were collected from a wastewater pump station in a Norwegian suburban community over a period of 15 months. A total of 45 daily samples were cultured and analyzed for the presence of Escherichia coli Eighty E. coli-like colonies were collected from each daily sample and then phenotyped and analyzed for antibiotic resistance using the PhenePlate-AREB system. During the sampling period, two unique E. coli phenotypes with resistance to cefotaxime and cefpodoxime indicating carriage of extended-spectrum ß-lactamases (ESBL) were observed repeatedly. Whole-genome sequencing of 15 representative isolates from the two phenotypes identified these as two distinct clones belonging to the two globally spread E. coli multilocus sequence types (STs) ST131 and ST648 and carrying blaCTX-M-15 The number of ESBL-positive E. coli strains in the community wastewater pump station was 314 of 3,123 (10%) analyzed E. coli strains. Of the ESBL-positive isolates, 37% belonged to ST648, and 7% belonged to ST131. Repeated findings of CTX-M-15-positive ST648 and ST131 over time indicate that these STs are resident in the analyzed wastewater systems and/or circulate abundantly in the community.


Assuntos
Infecções por Escherichia coli/enzimologia , Escherichia coli/enzimologia , Cefotaxima/farmacologia , Ceftizoxima/análogos & derivados , Ceftizoxima/farmacologia , Farmacorresistência Bacteriana Múltipla/genética , Escherichia coli/genética , Escherichia coli/metabolismo , Infecções por Escherichia coli/genética , Infecções por Escherichia coli/metabolismo , Testes de Sensibilidade Microbiana , Tipagem de Sequências Multilocus , Esgotos/microbiologia , Águas Residuárias/microbiologia , Sequenciamento Completo do Genoma/métodos , Cefpodoxima
11.
Bioinformatics ; 34(23): 4027-4033, 2018 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-29912385

RESUMO

Motivation: Correct taxonomic identification of DNA sequences is central to studies of biodiversity using both shotgun metagenomic and metabarcoding approaches. However, no genetic marker gives sufficient performance across all the biological kingdoms, hampering studies of taxonomic diversity in many groups of organisms. This has led to the adoption of a range of genetic markers for DNA metabarcoding. While many taxonomic classification software tools can be re-trained on these genetic markers, they are often designed with assumptions that impair their utility on genes other than the SSU and LSU rRNA. Here, we present an update to Metaxa2 that enables the use of any genetic marker for taxonomic classification of metagenome and amplicon sequence data. Results: We evaluated the Metaxa2 Database Builder on 11 commonly used barcoding regions and found that while there are wide differences in performance between different genetic markers, our software performs satisfactorily provided that the input taxonomy and sequence data are of high quality. Availability and implementation: Freely available on the web as part of the Metaxa2 package at http://microbiology.se/software/metaxa2/. Supplementary information: Supplementary data are available at Bioinformatics online.


Assuntos
Código de Barras de DNA Taxonômico , Marcadores Genéticos , Metagenômica , Filogenia , Software , Biologia Computacional
12.
BMC Biol ; 16(1): 84, 2018 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-30071832

RESUMO

BACKGROUND: Helicobacter pylori are stomach-dwelling bacteria that are present in about 50% of the global population. Infection is asymptomatic in most cases, but it has been associated with gastritis, gastric ulcers and gastric cancer. Epidemiological evidence shows that progression to cancer depends upon the host and pathogen factors, but questions remain about why cancer phenotypes develop in a minority of infected people. Here, we use comparative genomics approaches to understand how genetic variation amongst bacterial strains influences disease progression. RESULTS: We performed a genome-wide association study (GWAS) on 173 H. pylori isolates from the European population (hpEurope) with known disease aetiology, including 49 from individuals with gastric cancer. We identified SNPs and genes that differed in frequency between isolates from patients with gastric cancer and those with gastritis. The gastric cancer phenotype was associated with the presence of babA and genes in the cag pathogenicity island, one of the major virulence determinants of H. pylori, as well as non-synonymous variations in several less well-studied genes. We devised a simple risk score based on the risk level of associated elements present, which has the potential to identify strains that are likely to cause cancer but will require refinement and validation. CONCLUSION: There are a number of challenges to applying GWAS to bacterial infections, including the difficulty of obtaining matched controls, multiple strain colonization and the possibility that causative strains may not be present when disease is detected. Our results demonstrate that bacterial factors have a sufficiently strong influence on disease progression that even a small-scale GWAS can identify them. Therefore, H. pylori GWAS can elucidate mechanistic pathways to disease and guide clinical treatment options, including for asymptomatic carriers.


Assuntos
Variação Genética , Genoma Bacteriano , Estudo de Associação Genômica Ampla , Helicobacter pylori/genética , Neoplasias Gástricas/microbiologia , Gastrite/etiologia , Humanos , Metaplasia/etiologia , Polimorfismo de Nucleotídeo Único , Risco , Neoplasias Gástricas/epidemiologia , Fatores de Virulência/genética
13.
Infect Immun ; 85(10)2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28694295

RESUMO

Emerging evidence shows that the human microbiota plays a larger role in disease progression and health than previously anticipated. Helicobacter pylori, the causative agent of gastric cancer and duodenal and gastric ulcers, was early associated with gastric disease, but it has also been proposed that the accompanying microbiota in Helicobacter pylori-infected individuals might affect disease progression and gastric cancer development. In this study, the composition of the transcriptionally active microbial community and H. pylori gene expression were determined using metatranscriptomic RNA sequencing of stomach biopsy specimens from individuals with different H. pylori infection statuses and premalignant tissue changes. The results show that H. pylori completely dominates the microbiota not only in infected individuals but also in most individuals classified as H. pylori uninfected using conventional methods. Furthermore, H. pylori abundance is positively correlated with the presence of Campylobacter, Deinococcus, and Sulfurospirillum Finally, we quantified the expression of a large number of Helicobacter pylori genes and found high expression of genes involved in pH regulation and nickel transport. Our study is the first to dissect the viable microbiota of the human stomach by metatranscriptomic analysis, and it shows that metatranscriptomic analysis of the gastric microbiota is feasible and can provide new insights into how bacteria respond in vivo to variations in the stomach microenvironment and at different stages of disease progression.


Assuntos
Carcinogênese , Microbioma Gastrointestinal , Infecções por Helicobacter/microbiologia , Helicobacter pylori/genética , Neoplasias Gástricas/microbiologia , Estômago/microbiologia , Transcriptoma , Adulto , Idoso , Bactérias/genética , Bactérias/isolamento & purificação , Progressão da Doença , Feminino , Mucosa Gástrica/microbiologia , Gastrite Atrófica/microbiologia , Gastrite Atrófica/patologia , Perfilação da Expressão Gênica , Infecções por Helicobacter/patologia , Humanos , Masculino , Viabilidade Microbiana , Pessoa de Meia-Idade , Estômago/patologia , Adulto Jovem
14.
Helicobacter ; 22 Suppl 12017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28891132

RESUMO

As Helicobacter pylori infects half the world's population and displays an extensive intraspecies diversity, genomics is a powerful tool to understand evolution and disease, to identify factors that confer higher risk of severe sequelae, and to find new approaches for therapy both among bacterial and host targets. In line with these objectives, this review article summarizes the major findings in Helicobacter genomics in papers published between April 2016 and March 2017.


Assuntos
Genes Bacterianos , Genoma Bacteriano , Helicobacter pylori/genética , Evolução Molecular , Genômica , Helicobacter pylori/classificação , Helicobacter pylori/patogenicidade , Interações Hospedeiro-Patógeno , Humanos
15.
Proteomics ; 16(18): 2454-60, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27528420

RESUMO

Biology is increasingly dependent on large-scale analysis, such as proteomics, creating a requirement for efficient bioinformatics. Bioinformatic predictions of biological functions rely upon correctly annotated database sequences, and the presence of inaccurately annotated or otherwise poorly described sequences introduces noise and bias to biological analyses. Accurate annotations are, for example, pivotal for correct identification of polypeptide fragments. However, standards for how sequence databases are organized and presented are currently insufficient. Here, we propose five strategies to address fundamental issues in the annotation of sequence databases: (i) to clearly separate experimentally verified and unverified sequence entries; (ii) to enable a system for tracing the origins of annotations; (iii) to separate entries with high-quality, informative annotation from less useful ones; (iv) to integrate automated quality-control software whenever such tools exist; and (v) to facilitate postsubmission editing of annotations and metadata associated with sequences. We believe that implementation of these strategies, for example as requirements for publication of database papers, would enable biology to better take advantage of large-scale data.


Assuntos
Biologia Computacional/métodos , Bases de Dados de Proteínas , Software , Controle de Qualidade , Análise de Sequência
16.
BMC Evol Biol ; 16: 53, 2016 Feb 29.
Artigo em Inglês | MEDLINE | ID: mdl-26928576

RESUMO

BACKGROUND: Helicobacter pylori (H. pylori) is one of the most common bacterial infections in humans and this infection can lead to gastric ulcers and gastric cancer. H. pylori is one of the most genetically variable human pathogens and the ability of the bacterium to bind to the host epithelium as well as the presence of different virulence factors and genetic variants within these genes have been associated with disease severity. Nicaragua has particularly high gastric cancer incidence and we therefore studied Nicaraguan clinical H. pylori isolates for factors that could contribute to cancer risk. METHODS: The complete genomes of fifty-two Nicaraguan H. pylori isolates were sequenced and assembled de novo, and phylogenetic and virulence factor analyses were performed. RESULTS: The Nicaraguan isolates showed phylogenetic relationship with West African isolates in whole-genome sequence comparisons and with Western and urban South- and Central American isolates using MLSA (Multi-locus sequence analysis). A majority, 77 % of the isolates carried the cancer-associated virulence gene cagA and also the s1/i1/m1 vacuolating cytotoxin, vacA allele combination, which is linked to increased severity of disease. Specifically, we also found that Nicaraguan isolates have a blood group-binding adhesin (BabA) variant highly similar to previously reported BabA sequences from Latin America, including from isolates belonging to other phylogenetic groups. These BabA sequences were found to be under positive selection at several amino acid positions that differed from the global collection of isolates. CONCLUSION: The discovery of a Latin American BabA variant, independent of overall phylogenetic background, suggests hitherto unknown host or environmental factors within the Latin American population giving H. pylori isolates carrying this adhesin variant a selective advantage, which could affect pathogenesis and risk for sequelae through specific adherence properties.


Assuntos
Adesinas Bacterianas/genética , Helicobacter pylori/classificação , Helicobacter pylori/genética , Adesinas Bacterianas/química , Adolescente , Adulto , Idoso , Sequência de Aminoácidos , Antígenos de Bactérias/genética , Feminino , Variação Genética , Genoma Bacteriano , Infecções por Helicobacter/microbiologia , Helicobacter pylori/patogenicidade , Humanos , Pessoa de Meia-Idade , Dados de Sequência Molecular , Tipagem de Sequências Multilocus , Nicarágua , Filogenia , Fatores de Virulência/química , Fatores de Virulência/genética , Adulto Jovem
17.
Physiol Genomics ; 45(15): 667-83, 2013 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-23715263

RESUMO

In a screen for genes expressed specifically in gastric mucous neck cells, we identified GKN3, the recently discovered third member of the gastrokine family. We present confirmatory mouse data and novel porcine data showing that mouse GKN3 expression is confined to mucous cells of the corpus neck and antrum base and is prominently expressed in metaplastic lesions. GKN3 was proposed originally to be expressed in some human populations and a pseudogene in others. To investigate that hypothesis, we studied human GKN3 evolution in the context of its paralogous genomic neighbors, GKN1 and GKN2. Haplotype analysis revealed that GKN3 mimics GKN2 in patterns of exonic SNP allocation, whereas GKN1 appeared to be more stringently selected. GKN3 showed signatures of both directional selection and population based selective sweeps in humans. One such selective sweep includes SNP rs10187256, originally identified as an ancestral tryptophan to premature STOP codon mutation. The derived (nonancestral) allele went to fixation in Asia. We show that another SNP, rs75578132, identified 5 bp downstream of rs10187256, exhibits a second selective sweep in almost all Europeans, some Latinos, and some Africans, possibly resulting from a reintroduction of European genes during African colonization. Finally, we identify a mutation that would destroy the splice donor site in the putative exon3-intron3 boundary, which occurs in all human genomes examined to date. Our results highlight a stomach-specific human genetic locus, which has undergone various selective sweeps across European, Asian, and African populations and thus reflects geographic and ethnic patterns in genome evolution.


Assuntos
Proteínas de Transporte/genética , Evolução Molecular , Loci Gênicos/genética , Proteínas de Membrana/genética , Pseudogenes/genética , Grupos Raciais/genética , Seleção Genética/genética , Animais , Proteínas de Transporte/metabolismo , Biologia Computacional , Primers do DNA/genética , Imunofluorescência , Mucosa Gástrica/metabolismo , Genética Populacional , Genótipo , Haplótipos/genética , Humanos , Funções Verossimilhança , Macaca mulatta/genética , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL/genética , Análise em Microsséries , Microscopia Confocal , Modelos Genéticos , Mutação/genética , Filogenia , Polimorfismo de Nucleotídeo Único/genética , Especificidade da Espécie , Sus scrofa/genética
18.
mSystems ; 8(5): e0014123, 2023 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-37681982

RESUMO

IMPORTANCE: The importance of clean water cannot be overstated. It is a vital resource for maintaining health and well-being. Unfortunately, water sources contaminated with fecal discharges from animal and human origin due to a lack of wastewater management pose a significant risk to communities, as they can become a means of transmission of pathogenic bacteria like enterotoxigenic E. coli (ETEC). ETEC is frequently found in polluted water in countries with a high prevalence of diarrheal diseases, such as Bolivia. This study provides novel insights into the circulation of ETEC between diarrheal cases and polluted water sources in areas with high rates of diarrheal disease. These findings highlight the Choqueyapu River as a potential reservoir for emerging pathogens carrying antibiotic-resistance genes, making it a crucial area for monitoring and intervention. Furthermore, the results demonstrate the feasibility of a low-cost, high-throughput method for tracking bacterial pathogens in low- and middle-income countries, making it a valuable tool for One Health monitoring efforts.


Assuntos
Escherichia coli Enterotoxigênica , Infecções por Escherichia coli , Proteínas de Escherichia coli , Humanos , Escherichia coli Enterotoxigênica/genética , Infecções por Escherichia coli/epidemiologia , Proteínas de Escherichia coli/genética , Diarreia/epidemiologia , Água
19.
Microbiol Spectr ; 11(4): e0448622, 2023 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-37260395

RESUMO

The increasing prevalence of antibiotic-resistant bacteria is an emerging threat to global health. The analysis of antibiotic-resistant enterobacteria in wastewater can indicate the prevalence and spread of certain clonal groups of multiresistant bacteria. In a previous study of Escherichia coli that were isolated from a pump station in Norway over 15 months, we found a recurring E. coli clone that was resistant to trimethoprim, ampicillin, and tetracycline in 201 of 3,123 analyzed isolates (6.1%). 11 representative isolates were subjected to whole-genome sequencing and were found to belong to the MLST ST2797 E. coli clone with plasmids carrying resistance genes, including blaTEM-1B, sul2, dfrA7, and tetB. A phenotypic comparison of the ST2797 isolates with the uropathogenic ST131 and ST648 that were repeatedly identified in the same wastewater samples revealed that the ST2797 isolates exhibited a comparable capacity for temporal survival in wastewater, greater biofilm formation, and similar potential for the colonization of mammalian epithelial cells. ST2797 has been isolated from humans and has been found to carry extended spectrum ß-lactamase (ESBL) genes in other studies, suggesting that this clonal type is an emerging ESBL E. coli. Collectively, these findings show that ST2797 was more ubiquitous in the studied wastewater than were the infamous ST131 and ST648 and that ST2797 may have similar abilities to survive in the environment and cause infections in humans. IMPORTANCE The incidence of drug-resistant bacteria found in the environment is increasing together with the levels of antibiotic-resistant bacteria that cause infections. The COVID-19 pandemic has shed new light on the importance of monitoring emerging threats and finding early warning systems. Therefore, to mitigate the antimicrobial resistance burden, the monitoring and early identification of antibiotic-resistant bacteria in hot spots, such as wastewater treatment plants, are required to combat the occurrence and spread of antibiotic-resistant bacteria. Here, we applied a PhenePlate system as a phenotypic screening method for genomic surveillance and discovered a dominant and persistent E. coli clone ST2797 with a multidrug resistance pattern and equivalent phenotypic characteristics to those of the major pandemic lineages, namely, ST131 and ST648, which frequently carry ESBL genes. This study highlights the continuous surveillance and report of multidrug resistant bacteria with the potential to spread in One Health settings.


Assuntos
COVID-19 , Infecções por Escherichia coli , Animais , Humanos , Escherichia coli , Águas Residuárias , Tipagem de Sequências Multilocus , Pandemias , beta-Lactamases/genética , Antibacterianos/farmacologia , Infecções por Escherichia coli/epidemiologia , Infecções por Escherichia coli/microbiologia , Farmacorresistência Bacteriana Múltipla/genética , Mamíferos
20.
Antibiotics (Basel) ; 12(7)2023 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-37508214

RESUMO

We conducted a global-scale study to identify H. pylori antimicrobial-resistant genes (ARG), address their global distribution, and understand their effect on the antimicrobial resistance (AMR) phenotypes of the clinical isolates. We identified ARG using several well-known tools against extensive bacterial ARG databases, then analyzed their correlation with clinical antibiogram data from dozens of patients across countries. This revealed that combining multiple tools and databases, followed by manual selection of ARG from the annotation results, produces more conclusive results than using a single tool or database alone. After curation, the results showed that H. pylori has 42 ARG against 11 different antibiotic classes (16 genes related to single antibiotic class resistance and 26 genes related to multidrug resistance). Further analysis revealed that H. pylori naturally harbors ARG in the core genome, called the 'Set of ARG commonly found in the Core Genome of H. pylori (ARG-CORE)', while ARG-ACC-the ARG in the accessory genome-are exclusive to particular strains. In addition, we detected 29 genes of potential efflux pump-related AMR that were mostly categorized as ARG-CORE. The ARG distribution appears to be almost similar either by geographical or H. pylori populations perspective; however, some ARG had a unique distribution since they tend to be found only in a particular region or population. Finally, we demonstrated that the presence of ARG may not directly correlate with the sensitive/resistance phenotype of clinical patient isolates but may influence the minimum inhibitory concentration phenotype.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA