RESUMO
Agricultural biotechnology is limited by the inefficiencies of conventional random mutagenesis and transgenesis. Because targeted genome modification in plants has been intractable, plant trait engineering remains a laborious, time-consuming and unpredictable undertaking. Here we report a broadly applicable, versatile solution to this problem: the use of designed zinc-finger nucleases (ZFNs) that induce a double-stranded break at their target locus. We describe the use of ZFNs to modify endogenous loci in plants of the crop species Zea mays. We show that simultaneous expression of ZFNs and delivery of a simple heterologous donor molecule leads to precise targeted addition of an herbicide-tolerance gene at the intended locus in a significant number of isolated events. ZFN-modified maize plants faithfully transmit these genetic changes to the next generation. Insertional disruption of one target locus, IPK1, results in both herbicide tolerance and the expected alteration of the inositol phosphate profile in developing seeds. ZFNs can be used in any plant species amenable to DNA delivery; our results therefore establish a new strategy for plant genetic manipulation in basic science and agricultural applications.
Assuntos
Biotecnologia/métodos , Desoxirribonucleases/química , Desoxirribonucleases/metabolismo , Marcação de Genes/métodos , Genoma de Planta/genética , Zea mays/genética , Dedos de Zinco , Desoxirribonucleases/genética , Alimentos Geneticamente Modificados , Genes de Plantas/genética , Resistência a Herbicidas/genética , Herbicidas/farmacologia , Hereditariedade , Fosfatos de Inositol/metabolismo , Mutagênese Sítio-Dirigida/métodos , Plantas Geneticamente Modificadas , Recombinação Genética/genética , Reprodutibilidade dos TestesRESUMO
Capsule endoscopy is one of the main diagnostic methods of small bowel diseases. In small bowel capsule endoscopy, the main factors that influence the diagnostic rate of diseases include gastrointestinal examination completion rate and intestinal preparation, etc. The upper gastrointestinal transit time is one of the main influence factors of examination completion rate. This article reviewed risk factors and clinical management of prolonged upper gastrointestinal transit time in capsule endoscopy.