Glucosamine added to a transformation medium (TM2) after a 30-min cultivation of cells exhibited the highest inhibitory effect on the transformation process in Bacillus subtilis 168 trp2. The recipient culture was least sensitive to glucosamine added after 50 min. Glucosamine had no inhibitory effect when added 10 min after the transformation DNA.

• MeSH
• Bacillus subtilis * metabolism   MeSH
• Time Factors MeSH
• DNA, Bacterial metabolism   MeSH
• Glucose metabolism   MeSH
• Glucosamine pharmacology   MeSH
• Mutation MeSH
• Stereoisomerism MeSH
• Transformation, Genetic drug effects   MeSH
• Tryptophan biosynthesis   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• DNA, Bacterial MeSH
• Glucose MeSH
• Glucosamine MeSH
• Tryptophan MeSH

In the presence of amino sugars D-glucosamine and D-galactosamine no spontaneous competence could be observed in the highly transformable R6bd strain of Pneumococcus or it was decreased by several orders of magnitude. The highest inhibition of competence was detected when the amino sugar at a concentration 5 mg/ml of the medium was added not only to the transformation but also to the pretransformation medium. After a 150 min growth in the transformation medium in the presence of the amino sugar a 3--4-fold greater number of cells (as a viable count) could be detected as compared with the control without the amino sugar. It was found microscopically that the amino sugar prevents natural agglutination, which normally occurs in the competent culture. The role of specific amino sugar determinants for binding of the competence factor on the cell surface and the resulting inhibitory effect of these sugars on the development of competence are discussed.

• MeSH
• Agglutination drug effects   MeSH
• Amino Sugars pharmacology   MeSH
• Depression, Chemical MeSH
• DNA, Bacterial MeSH
• Galactosamine pharmacology   MeSH
• Glucosamine pharmacology   MeSH
• Mannose MeSH
• Stereoisomerism MeSH
• Streptococcus pneumoniae drug effects   immunology   MeSH
• Transformation, Genetic drug effects   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Amino Sugars MeSH
• DNA, Bacterial MeSH
• Galactosamine MeSH
• Glucosamine MeSH
• Mannose MeSH

• MeSH
• Acetylgalactosamine pharmacology   MeSH
• Amino Sugars pharmacology   MeSH
• Bacillus subtilis * MeSH
• DNA, Bacterial MeSH
• Galactosamine pharmacology   MeSH
• Glucosamine pharmacology   MeSH
• Streptococcus * MeSH
• Transformation, Genetic drug effects   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Acetylgalactosamine MeSH
• Amino Sugars MeSH
• DNA, Bacterial MeSH
• Galactosamine MeSH
• Glucosamine MeSH

The binding of the competence factor to cellular receptors of physiologically non-competent cells of Pneumococcus was followed as a function of time. A transformation medium without bovine serum albumin was used to study the binding of the competence factor. Control cells without the added factor remained completely non-competent under these conditions. The maximal binding of the factor to the cellular receptors took place already after 3 min of contact of the cells with the factor at 37 degrees C. After 10 min, when the maximum induction of competence occurs in the system used, the competence factor is fully released from the receptors to the medium. It follows that within the period between the 3rd and 10th min, when the cells are being modified for the irreversible binding of DNA, the presence of the competence factor on the cells is no longer necessary.

• MeSH
• Kinetics MeSH
• Receptors, Drug * MeSH
• Streptococcus pneumoniae metabolism   MeSH
• Transformation, Genetic * MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Receptors, Drug * MeSH

• MeSH
• Drug Resistance, Microbial * MeSH
• Time Factors MeSH
• Cells, Cultured * MeSH
• Spheroplasts drug effects   MeSH
• Streptococcus pneumoniae drug effects   MeSH
• Streptomycin pharmacology   MeSH
• Sulfanilamides pharmacology   MeSH
• Transformation, Genetic * MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Streptomycin MeSH
• Sulfanilamides MeSH