RESUMEN
THE BACILLUS megaterium exopolysaccharide [EPS] producer was isolated from the Egyptian soil and identified by molecular biology technique [16S rRNA]. It was found that the exopoiysaccharide showed a high yield after 72 hr, with an initial pH of 5.0, in 250 ml Erlenmeyer flasks containing 50 ml of culture, medium having 2% sucrose as a sole carbon source. The yeast extract [0.1%] and animonium chloride [0.1%] were the best organic and inorganic nitrogen source, respectively, as they gave the maximum EPS production. Optimum incubation temperature was found to be 35°C. Pretreated molasses from sugarcane and sugarbeet were used as carbon source and they gave a considerable yield [-tow fold] in relation to sucrose. The pretreatment of molasses by sulfuric acid showed high yield of polysaccharide and maximum yield coefficient
Asunto(s)
Bacillus megaterium/aislamiento & purificación , MelazaRESUMEN
Diarrhea continues to be one of the most common causes of morbidity and mortality among travelers and residents of developing countries especially infants and children. Enterotoxigenic E.coli is an emerging agent among pathogens that cause diarrhea. Enterotoxigenic E.coli produces either a heat-stable toxin or a heat-labile toxin, or both, encoded by plasmid-borne ST and LT genes, respectively. Diagnosis of infection with this subclass of E.coli can be performed with conventional biochemical reactions and API 20E system; however, the sensitivity and specificity of these methods are insufficient. A multiplex PCR assay that provides a sensitive and specific method for detecting the presence of either or both toxin genes has been developed. Two sets of primers were used to simultaneously detect the genes encoding LT and ST in order to detect all types of ETEC. The results for samples from patients indicated that the multiplex PCR assay had greater sensitivity and specificity than conventional biochemical reactions and API 20E system