RESUMEN
Salmonella enterica serovar Typhimurium is a facultative intracellular pathogen that utilizes its type III secretion systems (T3SSs) to inject virulence factors into the host cell and colonize the host. In turn, a subset of cytosolic immune receptors respond to T3SS ligands by forming multimeric signaling complexes called inflammasomes, which activate caspases that induce interleukin-1 (IL-1) family cytokine release and an inflammatory form of cell death called pyroptosis. Human macrophages mount a multifaceted inflammasome response to Salmonella infection that ultimately restricts intracellular bacterial replication. However, how inflammasomes restrict Salmonella replication remains unknown. We find that caspase-1 is essential for mediating inflammasome responses to Salmonella and subsequent restriction of bacterial replication within human macrophages, with caspase-4 contributing as well. We also demonstrate that the downstream pore-forming protein gasdermin D (GSDMD) and ninjurin-1 (NINJ1), a mediator of terminal cell lysis, play a role in controlling Salmonella replication in human macrophages. Notably, in the absence of inflammasome responses, we observed hyperreplication of Salmonella within the cytosol of infected cells, and we also observed increased bacterial replication within vacuoles, suggesting that inflammasomes control Salmonella replication primarily within the cytosol and also within vacuoles. These findings reveal that inflammatory caspases and pyroptotic factors mediate inflammasome responses that restrict the subcellular localization of intracellular Salmonella replication within human macrophages.
RESUMEN
Plant flavonoids are valuable natural antioxidants. Sweet potato (Ipomoea batatas) leaves are rich in flavonoids, regenerate rapidly, and can adapt to harsh environments, making them an ideal material for flavonoid biofortification. Here, we demonstrate that the B-box (BBX) family transcription factor IbBBX29 regulates the flavonoid contents and development of sweet potato leaves. IbBBX29 was highly expressed in sweet potato leaves and significantly induced by auxin (IAA). Overexpression of IbBBX29 contributed to a 21.37%-70.94% increase in leaf biomass, a 12.08%-21.85% increase in IAA levels, and a 31.33%-63.03% increase in flavonoid accumulation in sweet potato, whereas silencing this gene produced opposite effects. Heterologous expression of IbBBX29 in Arabidopsis (Arabidopsis thaliana) led to a dwarfed phenotype, along with enhanced IAA and flavonoid accumulation. RNA-seq analysis revealed that IbBBX29 modulates the expression of genes involved in the IAA signaling and flavonoid biosynthesis pathways. Chromatin immunoprecipitation-quantitative polymerase chain reaction and electrophoretic mobility shift assay indicated that IbBBX29 targets key genes of IAA signaling and flavonoid biosynthesis to activate their expression by binding to specific T/G-boxes in their promoters, especially those adjacent to the transcription start site. Moreover, IbBBX29 physically interacted with developmental and phenylpropanoid biosynthesis-related proteins, such as AGAMOUS-LIKE 21 protein IbAGL21 and MYB308-like protein IbMYB308L. Finally, overexpressing IbBBX29 also increased flavonoid contents in sweet potato storage roots. These findings indicate that IbBBX29 plays a pivotal role in regulating IAA-mediated leaf development and flavonoid biosynthesis in sweet potato and Arabidopsis, providing a candidate gene for flavonoid biofortification in plants.
Asunto(s)
Arabidopsis , Ipomoea batatas , Ipomoea batatas/genética , Ipomoea batatas/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Flavonoides/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Hojas de la Planta/genética , Hojas de la Planta/metabolismo , Regulación de la Expresión Génica de las PlantasRESUMEN
OBJECTIVE: To detect the etiologic agents of acute gastroenteritis (AGE) in children using broad molecular-based techniques, and compare clinical presentations among etiologies. STUDY DESIGN: This was a prospective population-based surveillance study of children aged <6 years with AGE conducted between 2008 and 2011 as part of the New Vaccine Surveillance Network. Stools from patients and healthy controls were tested for 21 gastrointestinal pathogens using the analyte-specific reagent Gastrointestinal Pathogen Panel and an additional reverse transcription real-time polymerase chain reaction assay for sapovirus and astrovirus. RESULTS: Of the 216 stool samples from patients with AGE, 152 (70.4%) tested positive for a pathogen, with norovirus genogroup II (n = 78; 36.1%) and Clostridium difficile (n = 35; 16.2%) the most common pathogens detected. Forty-nine patients (22.7%) tested positive for more than 1 pathogen, including 25 (71%) with a C difficile detection. There were no significant clinical differences among the patients with no pathogen detected, those with a single pathogen detected, and those with ≥2 pathogens detected. CONCLUSION: Using a broad molecular testing approach, high rates of enteropathogens were detected in children with AGE, dominated by norovirus genogroup II and C difficile. Coinfections were common but had no identifiable impact on clinical manifestations. As routine diagnostics of AGE progressively evolve toward nucleic acid-based pathogen detection, ongoing systematic studies are needed to better analyze the clinical significance of results.
Asunto(s)
Gastroenteritis/diagnóstico , Gastroenteritis/etiología , Enfermedad Aguda , Preescolar , Femenino , Gastroenteritis/microbiología , Gastroenteritis/parasitología , Humanos , Lactante , Recién Nacido , Masculino , Técnicas de Diagnóstico Molecular/métodos , Reacción en Cadena de la Polimerasa Multiplex , Vigilancia de la Población , Estudios ProspectivosRESUMEN
Durante el transcurso de los últimos años, el desarrollo y la aplicación de ténicas diagnósticas moleculares ha iniciado una revolución en el diagnóstico y monitoreo de las enfermedades infecciosas. las características fenotípicas microbianas están siendo utilizadas en la mayoría de los laboratorios de rutina para la identificación y diferenciación. Las técnicas con ácidos nucleicos, tales como los diversos métodos para generar polimorfismos de longitud en fracmentos de restricción en cadera de la polimerasa (PCR), incursionan cada vez con mayor frecuencia en los laboratorios clínicos. Las técnicas del PCR para detectar los agentes causales de enfermedad directamente de las mustras clínicas, sin la necesidad de cultivos, han sido útiles en la detección rápida de microorganismos no cultivables o exigentes. Además, el análisis de las secuencias amplificadas de DNA microbiano permite la identificación y una mejor caracterización del patógeno. La variación a nivel de subespecies, identificada por varias técnicas, ha demostrado ser importante en el pronóstico de ciertas enfermedades. Otros avances importantes incluyen la determinación de la carga viral y la detección de genes o mutaciones génicas responsables de la resistencia a drogas. La automatización y el software fácil de usar hacen que estas tecnologías estén disponibles. En todos los casos, la detección de agentes infecciosos a nivel de ácido nucleico representa una sítesis verdadera de las ténicas de quimica clínica y microbiología clínica.