RESUMEN
In this study, the effect of glycine betaine as osmoprotectant compound for Gluconacetobacter diazotrophicus PAL5 was evaluated by kinetic growth parameters. Batch fermentation assays were performed employing media supplemented with different sodium chloride concentrations to simulate saline stress conditions. Salt concentrations of 50-300 mM led to decreased cell concentrations, while the maximum specific growth rates and cell productivities were reduced at concentrations above 100-mM NaCl. Salt inhibition was mainly observed in media with 200- and 300-mM NaCl, in which drastic changes in cell morphology were also noted. The addition of glycine betaine to the media showed to be efficient to counteract the salt inhibitory effect by increasing some fermentation parameters. However, the osmoprotectant was not able to revert the polymorphism promoted by higher salt concentrations.
Asunto(s)
Betaína/farmacología , Gluconacetobacter/efectos de los fármacos , Medios de Cultivo/farmacología , Gluconacetobacter/crecimiento & desarrollo , Fijación del Nitrógeno/efectos de los fármacos , Cloruro de Sodio/farmacología , Equilibrio Hidroelectrolítico/efectos de los fármacosRESUMEN
UNLABELLED: The objective of this study was to examine the antibody responsiveness to the bundle-forming pilus subunit A of enteropathogenic Escherichia coli in human colostrum (n = 36) and serum (n = 90) of paediatric ambulatory patients, 3-24 months of age. Affinity purified recombinant bundle-forming pilus subunit A was used in immunoblot analysis to detect antigen-specific serum immunoglobulins G and A, and colostrum immunoglobulin A. Circulating immunoglobulin G antibody activity to the bundle-forming pilus subunit A was readily detected in all children. The frequency of immunoglobulin A antibody activity to the bundle-forming pilus subunit A in serum was 83.3%. Immunoglobulin A antibody activity to the bundle-forming pilus subunit A was detected in 75% of colostrum samples. The high frequency of immunoglobulin A antibody activity to the bundle-forming pilus subunit A observed in serum reveals a predominance of typical enteropathogenic Escherichia coli priming/infection in the study population. CONCLUSION: these findings demonstrate that the bundle-forming pilus subunit A is immunogenic, for both immunoglobulins G and A, in both pregnant/lactating women and asymptomatic children.
Asunto(s)
Anticuerpos Antibacterianos/análisis , Calostro/inmunología , Escherichia coli/inmunología , Lactancia/inmunología , Adolescente , Adulto , Anticuerpos Antibacterianos/sangre , Diarrea/sangre , Diarrea/inmunología , Infecciones por Escherichia coli/sangre , Infecciones por Escherichia coli/inmunología , Proteínas de Escherichia coli , Femenino , Proteínas Fimbrias , Fimbrias Bacterianas , Humanos , Immunoblotting , Inmunoglobulina A/análisis , Inmunoglobulina A/sangre , Inmunoglobulina G/análisis , Inmunoglobulina G/sangre , LactanteRESUMEN
A plant expression cassette system was engineered to efficiently target proteins to the default secretory pathway, allowing the expression of DNA inserts in three frames as fusion proteins containing a synthetic tobacco calreticulin cleavable signal peptide sequence, with the advantage of producing the recombinant proteins by phytosecretion. As one approach to develop a vaccine to enteropathogenic Escherichia coli (EPEC) infection, the oral immunogenicity of phytosecreted BfpA, the structural subunit A of the bundle-forming pilus, expressed at high levels (7.7% of soluble protein) in transgenic tobacco tissues, was demonstrated in BALB/c mice by the induction and detection of fecal anti-BfpA antibodies.