RESUMO
BACKGROUND: Infections with Taenia solium are the most common cause of adult acquired seizures worldwide, and are the leading cause of epilepsy in developing countries. A better understanding of the genetic diversity of T. solium will improve parasite diagnostics and transmission pathways in endemic areas thereby facilitating the design of future control measures and interventions. Microsatellite markers are useful genome features, which enable strain typing and identification in complex pathogen genomes. Here we describe microsatellite identification and characterization in T. solium, providing information that will assist in global efforts to control this important pathogen. METHODS: For genome sequencing, T. solium cysts and proglottids were collected from Huancayo and Puno in Peru, respectively. Using next generation sequencing (NGS) and de novo assembly, we assembled two draft genomes and one hybrid genome. Microsatellite sequences were identified and 36 of them were selected for further analysis. Twenty T. solium isolates were collected from Tumbes in the northern region, and twenty from Puno in the southern region of Peru. The size-polymorphism of the selected microsatellites was determined with multi-capillary electrophoresis. We analyzed the association between microsatellite polymorphism and the geographic origin of the samples. RESULTS: The predicted size of the hybrid (proglottid genome combined with cyst genome) T. solium genome was 111 MB with a GC content of 42.54%. A total of 7,979 contigs (>1,000 nt) were obtained. We identified 9,129 microsatellites in the Puno-proglottid genome and 9,936 in the Huancayo-cyst genome, with 5 or more repeats, ranging from mono- to hexa-nucleotide. Seven microsatellites were polymorphic and 29 were monomorphic within the analyzed isolates. T. solium tapeworms were classified into two genetic groups that correlated with the North/South geographic origin of the parasites. CONCLUSIONS/SIGNIFICANCE: The availability of draft genomes for T. solium represents a significant step towards the understanding the biology of the parasite. We report here a set of T. solium polymorphic microsatellite markers that appear promising for genetic epidemiology studies.
Assuntos
Variação Genética , Genoma Helmíntico/genética , Repetições de Microssatélites/genética , Taenia solium/genética , Teníase/parasitologia , Adulto , Animais , Sequência de Bases , Mapeamento Cromossômico , DNA de Helmintos/química , DNA de Helmintos/genética , Genótipo , Geografia , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Dados de Sequência Molecular , Peru/epidemiologia , Análise de Sequência de DNA , Taenia solium/isolamento & purificação , Teníase/epidemiologiaRESUMO
BACKGROUND. Hepatitis C virus (HCV) infects approximately 170 million people worldwide and may lead to cirrhosis and hepatocellular carcinoma in chronically infected individuals. Treatment is rapidly evolving from IFN-α-based therapies to IFN-α-free regimens that consist of directly acting antiviral agents (DAAs), which demonstrate improved efficacy and tolerability in clinical trials. Virologic relapse after DAA therapy is a common cause of treatment failure; however, it is not clear why relapse occurs or whether certain individuals are more prone to recurrent viremia. METHODS. We conducted a clinical trial using the DAA sofosbuvir plus ribavirin (SOF/RBV) and performed detailed mRNA expression analysis in liver and peripheral blood from patients who achieved either a sustained virologic response (SVR) or relapsed. RESULTS. On-treatment viral clearance was accompanied by rapid downregulation of IFN-stimulated genes (ISGs) in liver and blood, regardless of treatment outcome. Analysis of paired pretreatment and end of treatment (EOT) liver biopsies from SVR patients showed that viral clearance was accompanied by decreased expression of type II and III IFNs, but unexpectedly increased expression of the type I IFN IFNA2. mRNA expression of ISGs was higher in EOT liver biopsies of patients who achieved SVR than in patients who later relapsed. CONCLUSION. These results suggest that restoration of type I intrahepatic IFN signaling by EOT may facilitate HCV eradication and prevention of relapse upon withdrawal of SOF/RBV. TRIAL REGISTRATION. ClinicalTrials.gov NCT01441180.
Assuntos
Antivirais/administração & dosagem , Hepatite C Crônica/tratamento farmacológico , Hepatite C Crônica/imunologia , Interferons/metabolismo , Fígado/imunologia , Ribavirina/administração & dosagem , Uridina Monofosfato/análogos & derivados , Quimiocina CXCL10/sangue , Quimioterapia Combinada , Endopeptidases/genética , Expressão Gênica/efeitos dos fármacos , Hepatite C Crônica/genética , Humanos , Interferon-alfa/genética , Interferon-alfa/metabolismo , Interferons/classificação , Interferons/genética , Interleucinas/genética , Fígado/metabolismo , RNA Mensageiro/sangue , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Recidiva , Sofosbuvir , Resultado do Tratamento , Ubiquitina Tiolesterase , Uridina Monofosfato/administração & dosagemRESUMO
To better understand the molecular events involved in the origin of new pathogenic bacteria, we studied the evolution of a highly virulent clone of serotype M1 group A Streptococcus (GAS). Genomic, DNA-DNA microarray, and single-nucleotide polymorphism analyses indicated that this clone evolved through a series of horizontal gene transfer events that involved (1) the acquisition of prophages encoding streptococcal pyrogenic exotoxin A and extracellular DNases and (2) the reciprocal recombination of a 36-kb chromosomal region encoding the extracellular toxins NAD+-glycohydrolase (NADase) and streptolysin O (SLO). These gene transfer events were associated with significantly increased production of SLO and NADase. Virtual identity in the 36-kb region present in contemporary serotype M1 and M12 isolates suggests that a serotype M12 strain served as the donor of this region. Multiple horizontal gene transfer events were a crucial factor in the evolutionary origin and emergence of a very abundant contemporary clone of serotype M1 GAS.