ABSTRACT
A modification of the traditional method for lipoplysaccharide isolation from the cells of grammnegative bacteria was elaborated on the basis of extraction by the hot water solution of phenol (the method of Westfahl). To make the method simpler and to raise the yield of the product it was proposed to use the water-phenol extract without its division for plases. The nucleic acids are eliminated by precipitation from dialyzed extract at pH 3,2-3,4 achieved by addition of acetic acid. The comparative isolation of lipopolysaccharides by the classic and modified methods has confirmed the advantages of a new technique.
Subject(s)
Gram-Negative Bacteria/analysis , Lipopolysaccharides/isolation & purification , Gram-Negative Bacteria/immunology , Methods , Pseudomonas aeruginosa/analysis , Pseudomonas aeruginosa/immunology , Shigella boydii/analysis , Shigella boydii/immunologyABSTRACT
Shigella boydii 13 strains are separable from other Shigella and Escherichia coli strains on the basis of DNA relatedness. From this observation, it was possible to confirm the existence of aerogenic S. boydii 13 strains. DNA relatedness studies also showed that strains of E. coli and strains representing all other serotypes of Shigella, including provisional strains, belong to the same genetic species.
Subject(s)
DNA, Bacterial/analysis , Shigella boydii/classification , Shigella/classification , Escherichia coli/classification , Serotyping , Shigella boydii/analysisABSTRACT
Escherichia coli strains that cause dysentery-like disease, parenteral infection, and infantile diarrhea form specific groups based on mobility of O and K antigens in immunoelectrophoresis. Members from each of these groups were assayed for gross nucleotide sequence relatedness. The method used was interspecific deoxyribonucleic acid (DNA) reassociation reactions carried out free in solution. Reassociated DNA was separated from unreacted DNA by passage through hydroxyapatite. DNA relatedness between these groups was approximately 80%. The groups containing those strains causing parenteral infection and those responsible for dysentery-like disease showed preferentially high intragroup DNA relatedness. The group containing strains responsible for infantile diarrhea did not show preferentially high intragroup DNA relatedness with the reference strain employed. These strains, however, did exhibit preferentially high DNA relatedness to a second reference strain.
