RESUMO
A hybridoma cell line producing a rat monoclonal antibody (MAb Bo-33) directed against lipopolysaccharide of Azospirillum brasilense Wa5 has been established and characterized. Whole bacteria were used as immunogens. The number of antigens per cell was about 1500. The number of antigens per cell of reisolates from the rhizosphere of what was similar to the number of antigens of bacteria cultivated in rich medium. The sensitivity of detection using MAb Bo-33 was about 100 bacteria/ml. Therefore, the MAb was suitable for in situ immunofluorescence detection and a sensitive direct quantification of Azospirillum brasilense Wa5 in rhizosphere extracts.
Assuntos
Anticorpos Antibacterianos/imunologia , Azospirillum brasilense/imunologia , Lipopolissacarídeos/imunologia , Raízes de Plantas/microbiologia , Microbiologia do Solo , Animais , Anticorpos Monoclonais , Especificidade de Anticorpos , Azospirillum brasilense/isolamento & purificação , Ensaio de Imunoadsorção Enzimática , Epitopos , Imunofluorescência , Hibridomas , Lipopolissacarídeos/isolamento & purificação , Ratos , Triticum/microbiologiaRESUMO
The induction of the lateral flagella of Azospirillum brasilense Sp7 was studied by using a translational fusion between the laf1 promoter and gusA. The fusion was induced when cells were grown on solid media but not when they were grown in broth. The fusion was also induced by incubation of liquid-grown cells with an anti-polar flagellum polyclonal antiserum. Hindrance of polar-flagellum rotation is suggested to be the signal for this induction.
Assuntos
Azospirillum brasilense/genética , Azospirillum brasilense/metabolismo , Proteínas de Bactérias , Flagelos/fisiologia , Flagelina/biossíntese , Genes Bacterianos , Sequência de Aminoácidos , Sequência de Bases , Flagelina/genética , Glucuronidase/biossíntese , Cinética , Dados de Sequência Molecular , Regiões Promotoras Genéticas , Biossíntese de Proteínas , Proteínas Recombinantes de Fusão/biossíntese , Transcrição GênicaRESUMO
Several hybridoma cell lines producing murine monoclonal antibodies (MAbs) directed against outer membrane components of the Gram-negative rhizosphere bacterium Azospirillum brasilense Sp245 have been established and characterized. Whole bacterial cells were used as immunogens. Among the clones obtained, 14 hybridoma cell lines were selected for further characterization. Eight MAbs were strain-specific and 6 MAbs showed cross-reactivity with a closely related strain Azospirillum brasilense Sp246. According to the biochemical characterization of the antigenic determinants, MAbs were classified into four groups. The corresponding antigens were lipopolysaccharides (class 1) and an outer membrane protein (class 4), which is common to Azospirillum brasilense Sp245 and Azospirillum brasilense Sp246 as well as two outer membrane proteins (class 2 and class 3) that are characteristic for Azospirillum brasilense Sp245. The number of antigens per cell varied from 4000 (class 1) to 100 (class 4). In each class high affinity MAbs were identified, which made a sensitive direct quantification of Azospirillum brasilense Sp245 possible.