RESUMO
No disponible
Assuntos
Humanos , Feminino , Adolescente , Obstrução das Vias Respiratórias/etiologia , Obstrução das Vias Respiratórias/terapia , Oxigenação por Membrana Extracorpórea , Doenças Inflamatórias Intestinais/complicaçõesRESUMO
This work presents the results obtained from the dosimetric properties of the new radiation detectors of KMgF3:Tbâ¯+â¯PTFE. The thermoluminescent material was obtained by microwave technique. The polycrystalline powder obtained was mixed with polytetrafluoroethylene resin powder in the ratio 2:3 to make dosimeters in pellet form. The thermoluminescent response of these new detectors presented a linear behavior, in the dose range between 1 and 1000â¯Gy 60Co gamma radiation, the repeatability test in the measurements, during ten cycles of heat treatment, irradiation and readouts, showed ±â¯3.7% DS, the stability test of thermoluminescent signal, during two months showed that the fading is practically null. For the results obtained, this new detector could be very useful for radiation dosimetry, in clinical applications.
Assuntos
Dosimetria Termoluminescente/métodos , Radioisótopos de Cobalto , Fluoretos , Raios gama , Humanos , Compostos de Magnésio , Politetrafluoretileno , Compostos de Potássio , Térbio , Dosimetria Termoluminescente/estatística & dados numéricosRESUMO
The basic replicon of Rhizobium etli CE3, like other members of the repABC plasmid family, is constituted by the repABC operon. RepC is essential for replication, and RepA and RepB play a role in plasmid segregation. It has been shown that deletion derivatives lacking the repAB genes have an increased copy number, indicating that these genes participate in the control of plasmid copy number. RepA is also a trans-incompatibility factor. To understand the regulation of the repABC operon, in this paper: (i) the transcription start site of the repABC operon was determined; (ii) the promoter region was identified by site-directed mutagenesis of the putative -35 and -10 hexameric elements; and (iii) RepA was recognized as a negative regulator of the transcription of the repABC operon.
Assuntos
Proteínas de Bactérias/metabolismo , DNA Helicases , Proteínas de Ligação a DNA , Óperon/genética , Proteínas/metabolismo , Rhizobium/genética , Transativadores , Transcrição Gênica , Proteínas de Bactérias/genética , Sequência de Bases , Pegada de DNA , Regulação Bacteriana da Expressão Gênica , Genes Reporter , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Regiões Promotoras Genéticas , Proteínas/genética , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Rhizobium/fisiologia , Alinhamento de SequênciaRESUMO
The symbiotic plasmid of Rhizobium etli CE3 belongs to the RepABC family of plasmid replicons. This family is characterized by the presence of three conserved genes, repA, repB, and repC, encoded by the same DNA strand. A long intergenic sequence (igs) between repB and repC is also conserved in all members of the plasmid family. In this paper we demonstrate that (i) the repABC genes are organized in an operon; (ii) the RepC product is essential for replication; (iii) RepA and RepB products participate in plasmid segregation and in the regulation of plasmid copy number; (iv) there are two cis-acting incompatibility regions, one located in the igs (incalpha) and the other downstream of repC (incbeta) (the former is essential for replication); and (v) RepA is a trans-acting incompatibility factor. We suggest that incalpha is a cis-acting site required for plasmid partitioning and that the origin of replication lies within incbeta.
