RESUMO
In order to detect phenotypic characteristics associated with pathogenicity, 25 strains of Escherichia coli, isolated from clinical cases of colisepticemia in broiler chickens, were examined to determine the following properties: colicinogenicity, colicin V production, type 1 fimbriae, hemolysin expression and motility. Colicinogenicity occurred in 72% of the strains, 56% of all strains produced colicin V, 84% were positive for type 1 fimbriae and 80% were positive for motility. None of the strains had hemolytic activity; however, all of them, expressed at least one of the other characteristics studied. These results suggest that the diversity of phenotypes detected partially explain the multifactorial nature of avian colisepticemia.
Assuntos
Infecções por Escherichia coli/veterinária , Escherichia coli/patogenicidade , Doenças das Aves Domésticas/microbiologia , Sepse/veterinária , Técnicas de Tipagem Bacteriana , Plasmídeos de Bacteriocinas , Técnicas Bacteriológicas , Colicinas/análise , Escherichia coli/isolamento & purificação , Infecções por Escherichia coli/microbiologia , Fímbrias Bacterianas/ultraestrutura , Técnica de Placa Hemolítica , México , Fenótipo , Sepse/microbiologia , VirulênciaRESUMO
In order to detect phenotypic characteristics associated with pathogenicity, 25 strains of Escherichia coli, isolated from clinical cases of colisepticemia in broiler chickens, were examined to determine the following properties: colicinogenicity, colicin V production, type 1 fimbriae, hemolysin expression and motility. Colicinogenicity occurred in 72
of the strains, 56
of all strains produced colicin V, 84
were positive for type 1 fimbriae and 80
were positive for motility. None of the strains had hemolytic activity; however, all of them, expressed at least one of the other characteristics studied. These results suggest that the diversity of phenotypes detected partially explain the multifactorial nature of avian colisepticemia.
RESUMO
PURPOSE AND METHODS: We investigated the expression and localization of topoisomerase I by Western blot and indirect fluorescent antibody assay, respectively, using anti-Scl-70/topo I from patients with diffuse scleroderma. The contribution of topoisomerase I to DNA replication was assessed using cells treated with the topoisomerase I inhibitor camptothecin. RESULTS: Scl-topo I was detected at all cell cycle phases as a single immunoreactive band of 100 kDa. Extracts from cells in the S phase contained the largest amount of immunoreactive Scl-70/topo I. Variations in the subcellular distribution of Scl-70/topo I were seen throughout the cell cycle, with a speckled nucleoplasmic distribution during G1 contrasting with concentration within the nucleolus during S. Camptothecin exposure blocked topoisomerase I expression and caused a significant decrease in DNA production. CONCLUSION: These data suggest (1) that topomerase I is active mainly during the S phase and contributes to DNA replication, and (2) that topoisomerase I may be involved in ribosomal gene transcription.
Assuntos
DNA Topoisomerases Tipo I/metabolismo , Proteínas Nucleares/metabolismo , Antineoplásicos Fitogênicos/farmacologia , Autoantígenos/análise , Autoantígenos/genética , Autoantígenos/metabolismo , Western Blotting , Camptotecina/farmacologia , Ciclo Celular/efeitos dos fármacos , Ciclo Celular/imunologia , Divisão Celular/efeitos dos fármacos , Replicação do DNA/efeitos dos fármacos , Replicação do DNA/imunologia , DNA Topoisomerases Tipo I/análise , Técnica Indireta de Fluorescência para Anticorpo , Humanos , Hidroxiureia/farmacologia , Índice Mitótico , Proteínas Nucleares/antagonistas & inibidores , Proteínas Nucleares/genética , Inibidores da Síntese de Ácido Nucleico/farmacologia , Fase S , Escleroderma Sistêmico/enzimologia , Escleroderma Sistêmico/metabolismo , Inibidores da Topoisomerase I , Células Tumorais Cultivadas/química , Células Tumorais Cultivadas/citologia , Células Tumorais Cultivadas/enzimologiaRESUMO
The purpose of this study was to determine whether phosphorylation has an effect on the characteristics of the 60 kD Ro antigen throughout the cell cycle. Cell extracts of synchronized HEp-2 cells were phosphorylated in vitro with exogenous ATP, examined by SDS-PAGE and Western blot, and probed with specific anti-Ro sera. In addition, cellular ATP pools were radiolabelled in vivo with 32P. The presence of the Ro protein was detected with a molecular weight of 60 kD during all phases of the cell cycle, except at the M phase, where it was increased to 65 kD. Phosphorylation of the in vitro and in vivo cell extracts increased the molecular mass to 65 kD. Moreover immunoprecipitation assays demonstrated that Ro is hyperphosphorylated in the M phase. Phosphorylation did not change the recognition pattern of the anti-Ro sera.
