RESUMO
The promoter region of pyrC (dihydroorotase) gene of Escherichia coli was shown to have Fur protein binding properties by gel retardation assay. In vivo regulation of the pyrC expression was studied by measuring dihydroorotase activity and beta-galactosidase level in the fur+ and fur- genetic background. The expression of chromosomal dihydroorotase activity and beta-galactosidase activity of pyrC-lacZ fusion plasmid was repressed to about 30% and 17%, respectively in the fur+ strain compared to those in the fur- strain. Divalent ions such as Fe2+ and Zn2+ were not required for the repression. PyrC expression was also reduced to one half by 1 mM uracil. The effect of uracil was independent on the fur gene.
Assuntos
Proteínas de Bactérias/genética , Di-Hidro-Orotase/genética , Proteínas de Escherichia coli/genética , Regulação Bacteriana da Expressão Gênica , Proteínas Repressoras/genética , Proteínas de Bactérias/metabolismo , Sequência de Bases , Clonagem Molecular , Di-Hidro-Orotase/metabolismo , Ensaio de Desvio de Mobilidade Eletroforética , Proteínas de Escherichia coli/metabolismo , Expressão Gênica/efeitos dos fármacos , Modelos Genéticos , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Mutação , Regiões Promotoras Genéticas/genética , Ligação Proteica , Proteínas Repressoras/metabolismo , Análise de Sequência de DNA , Uracila/farmacologiaRESUMO
One of the main concerns in nanotechnology is the utilization of nanomaterials in macroscopic applications without losing their extreme properties. In an effort to bridge the gap between the nano- and macroscales, we propose a clever fabrication method, the inverted floating method (IFM), for preparing freestanding chemical-vapor-deposited (CVD) graphene membranes. These freestanding membranes were then successfully suspended over a gap a half-millimeter in diameter. To understand the working principle of IFM, high-speed photography and white light interferometry were used to characterize and analyze the deformation behaviors of the freestanding graphene membranes in contact with a liquid during fabrication. Some nanoscale configurations in the macroscopic graphene membranes were able to be characterized by simple optical microscopy. The proposed IFM is a powerful approach to investigating the macroscopic structures of CVD graphene and enables the exploitation of freestanding CVD graphene for device applications.
RESUMO
INTRODUCTION: Fusion is a rare occurrence, and its definitive diagnosis is of prime importance for successful root canal treatment. This case report discusses the endodontic management of a supernumerary tooth fused with a right maxillary first molar by using cone-beam computed tomography (CBCT). METHODS: Nonsurgical endodontic retreatment was performed on the supernumerary tooth. A communication between the maxillary first molar and the supernumerary tooth was repaired by using flowable resin. RESULTS: After 1 year of follow-up, there were no clinical symptoms, and the maxillary first molar remained vital. Recall radiographs and CBCT showed satisfactory healing of the periapical pathosis. CONCLUSIONS: Proper diagnosis and treatment planning for endodontic management of fused teeth by using CBCT can ensure predictable and successful results.