ABSTRACT
Symbiotic nitrogen-fixing bacteria Rhizobium leguminosarum by. viciae VF39 secrete an acidic heteropolysaccharide, the biosynthesis of which involves the stage of polyprenyl diphosphate octasaccharide formation, with its carbohydrate fragment corresponding to the repeating polymer unit. The amino acid analysis of the product of the pssA gene, we have earlier identified, showed its homology to bacterial polyisoprenyl phosphate hexose 1-phosphate transferases catalyzing the formation of phosphodiester bonds between polyprenyl phosphates and hexose 1-phosphates, whose donors are nucleotide sugars. The immunoblotting demonstrated that Rhizobium cells synthesize a protein with a molecular mass of 25 kDa, which implies the translation of the open reading frame occurring from the second initiating codon followed by the protein processing. It was shown that PssA is an integral membrane-bound protein involved in glucose 1-phosphate transfer from UDP-glucose to polyprenyl phosphate to form polyprenyl diphosphate glucose. These results suggest that the pssA gene encodes UDP-glucose:polyprenyl phosphate-glucosyl phosphotransferase.
Subject(s)
Bacterial Proteins/genetics , Glycosyltransferases/genetics , Membrane Proteins/genetics , Polysaccharides, Bacterial/biosynthesis , Rhizobium leguminosarum/enzymology , Amino Acid Sequence , Bacterial Proteins/analysis , Blotting, Western , Cloning, Molecular , Escherichia coli/genetics , Glycosyltransferases/analysis , Membrane Proteins/analysis , Molecular Sequence Data , Polysaccharides, Bacterial/chemistry , Polysaccharides, Bacterial/genetics , Rhizobium leguminosarum/genetics , Sequence AlignmentABSTRACT
Effects of the structure of plasmids carrying the cloned delta-endotoxin gene (tox) ot Bacillus thuringiensis and of the culture media on the expression of the gene have been studied. The DNA region located upstream from the crystal protein gene promoter inhibited the expression of the tox gene in Escherichia coli cells, but enhanced the expression in Bacillus megaterium cells grown in LB medium. The upstream DNA region did not affect the tox gene expression when Bacillus megaterium cells were grown in SSM medium.
Subject(s)
Bacillus thuringiensis/genetics , Bacterial Proteins , Bacterial Toxins , Endotoxins/genetics , Gene Expression Regulation, Bacterial , Genes, Bacterial , Bacillus megaterium/genetics , Bacillus thuringiensis Toxins , Cloning, Molecular , Escherichia coli/genetics , Hemolysin Proteins , Immunoelectrophoresis, Two-Dimensional , Plasmids , Recombination, GeneticABSTRACT
ELISA in which P. aeruginosa slime preparations are used as antigens permits the detection of antibodies to this microorganism in the blood sera of patients with acute and chronic pulmonary diseases induced by P. aeruginosa. This assay makes it possible to find out the etiology of infection even before the results of bacteriological investigation are obtained.
Subject(s)
Antibodies, Bacterial/analysis , Antibody Specificity , Lung Diseases/diagnosis , Pseudomonas Infections/diagnosis , Pseudomonas aeruginosa/immunology , Adolescent , Adult , Child , Child, Preschool , Humans , Immunoenzyme Techniques , Infant , Middle Aged , Mucus/immunologyABSTRACT
To determine the content of lipopolysaccharide (LPS) in P. aeruginosa aqueous extracts the ELISA was used. Membrane filtration and ultracentrifugation followed by precipitation with ammonium sulfate at 80% saturation and gel filtration on Sephadex G-100 have proved to be the most effective methods for purification of the aqueous extract from LPS.
