RESUMO
The occurrence of human infections with avian H7N9 viruses since 2013 demonstrates the continuing pandemic threat posed by the current influenza ecosystem in China. Influenza surveillance and phylogenetic analyses showed that these viruses were generated by multiple interspecies transmissions and reassortments among the viruses resident in domestic ducks and the H9N2 viruses enzootic in chickens. A large population of domestic ducks hosting diverse influenza viruses provided the precondition for these events to occur, while acquiring internal genes from enzootic H9N2 influenza viruses in chickens promoted the spread of these viruses. Human infections effectively act as sentinels, reflecting the intensity of the activity of these viruses in poultry.
Assuntos
Doenças Transmissíveis Emergentes , Subtipo H7N9 do Vírus da Influenza A/classificação , Influenza Humana/epidemiologia , Influenza Humana/virologia , Animais , Galinhas , China/epidemiologia , Patos , Evolução Molecular , Genótipo , Humanos , Subtipo H7N9 do Vírus da Influenza A/genética , Subtipo H7N9 do Vírus da Influenza A/isolamento & purificação , Influenza Aviária/epidemiologia , Influenza Aviária/transmissão , Influenza Aviária/virologia , Influenza Humana/transmissão , Filogenia , Vírus Reordenados , Fatores de RiscoRESUMO
Progress in bacterial therapy for cancer and infectious diseases is hampered by the absence of safe and efficient vectors. Sustained delivery and high gene expression levels are critical for the therapeutic efficacy. Here we developed a Salmonella typhimrium strain to maintain and safely deliver a plasmid vector to target tissues. This vector is designed to allow dual transcription of therapeutic factors, such as cytotoxic proteins, short hairpin RNAs or combinations, in the nucleus or cytoplasm of eukaryotic cells, with this expression sustained by an autocatalytic positive-feedback loop. Mechanisms to prime the system and maintain the plasmid in the bacterium are also provided. Synergistic effects of attenuated Salmonella and our inter-kingdom system allow the precise expression of Diphtheria toxin A chain (DTA) gene in tumor microenvironment and eradicate large established tumors in immunocompetent animals. In the experiments reported here, 26% of mice (n=5/19) with aggressive tumors were cured and the others all survived until the end of the experiment. We also demonstrated that ST4 packaged with shRNA-encoding plasmids has sustained knockdown effects in nude mice bearing human MDA-MB-231 xenografts. Three weeks after injection of 5×10(6) ST4/pIKT-shPlk, PLK1 transcript levels in tumors were 62.5±18.6% lower than the vector control group (P=0.015). The presence of PLK1 5' RACE-PCR cleavage products confirmed a sustained RNAi-mediated mechanism of action. This innovative technology provides an effective and versatile vehicle for efficient inter-kingdom gene delivery that can be applied to cancer therapy and other purposes.
Assuntos
Terapia Genética/métodos , Salmonella typhimurium/genética , Animais , Proteínas de Ciclo Celular/genética , Linhagem Celular Tumoral , Toxina Diftérica/genética , Retroalimentação Fisiológica , Feminino , Vetores Genéticos , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Neoplasias/terapia , Fragmentos de Peptídeos/genética , Plasmídeos , Proteínas Serina-Treonina Quinases/genética , Proteínas Proto-Oncogênicas/genética , Interferência de RNA , RNA Interferente Pequeno/genética , Quinase 1 Polo-LikeRESUMO
Recent founder mutations may play important roles in complex diseases and Mendelian disorders. Detecting shared haplotypes that are identical by descent (IBD) could facilitate discovery of these mutations. Several programs address this, but are usually limited to detecting pair-wise shared haplotypes and not providing a comparison of cases and controls. We present a novel algorithm and software package, HaploShare, which detects extended haplotypes that are shared by multiple individuals, and allows comparisons between cases and controls. Testing on simulated and real cases demonstrated significant improvements in detection power and reduction of false positive rate by HaploShare relative to other programs.
Assuntos
Biologia Computacional , Estudos de Associação Genética/métodos , Haplótipos , Algoritmos , Povo Asiático/genética , Estudos de Casos e Controles , Reações Falso-Positivas , Doença de Hirschsprung/diagnóstico , Doença de Hirschsprung/genética , Humanos , Mutação , Polimorfismo de Nucleotídeo Único , Sensibilidade e EspecificidadeRESUMO
Marfan syndrome is an autosomal dominant connective tissue disorder, and mutations in the FBN1 and TGFBR2 genes have been identified in probands with MFS and related phenotypes. Using DHPLC and sequencing, we studied the mutation spectrum in 65 probands with Marfan syndrome and related phenotypes. A total of 24 mutations in FBN1 were identified, of which 19 (nine missense, six frameshift, two nonsense and two affecting splice junctions) were novel. In the remaining 41 probands, six were identified to have novel TGFBR2 mutations (one frameshift and five missense mutations). All novel mutations found in this study were confirmed to be absent in 50 unrelated normal individuals of the same ethnic background. In probands who fulfilled the Ghent criteria (n = 16), mutations in FBN1 were found in 81% of cases. None of those with TGFBR2 mutations fulfilled the Ghent criteria. Novel missense mutations of unknown significance were classified according to the latest ACMG guidelines and their likelihood to be causative was evaluated.