Streptomycin and lysozyme

Résumé Les microorganismes sensibles au lysozyme ne subissent pas l'agglutination par la streptomycine. Inversement, la streptomycine empêche la clarification des suspensions microbiennes par le lysozyme. Cet effet est attribuable à la prévention de la dissolution des noyaux. Les mutants résistants à la streptomycine restent sensibles au lysozyme et se comportent, en présence de streptomycine plus lysozyme, comme les souches-mères.

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Lysozyme-sensitive microorganisms are not subject to streptomycin-agglutination. Conversely, streptomycin inhibits the clarification of bacterial suspensions by lysozyme. This effect is mainly due to a prevention of nuclear dissolution. Streptomycin-resistant mutants remain lysozyme-sensitive and behave towards streptomycin plus lysozyme as do parent-cells.

     

Streptomycin

Summary Streptomyces griseus DTH-2 was grown in 5 1 fermentors on complex media containing calcium carbonate as a buffering agent. It was shown that automatic pH control (4N KOH) could substitute the calcium carbonate giving higher yields of streptomycin. The yield was further increased by omitting inorganic phosphate from the medium and by differential addition of glucose/ammonium sulphate during the fermentation. The maximal yield obtained was 8.5 g of streptomycin per liter.     

Streptomycin biosynthesis and its regulation in Streptomycetes.

New insights into the gene orders, structures, evolution, and functions of streptomycin (Sm) biosynthetic genes (str) were gained via hybridization studies, determination of nucleotide sequences, and measurement of expression in the str gene clusters of Streptomyces griseus and S. glaucescens. Both str clusters showed considerable divergence in macro and micro structure. Genes putatively involved in pathways leading to the (dihydro-)streptose and N-methyl-L-glucosamine moieties of Sm were identified. Additional regulatory elements, such as gene strS and conserved TTA codons in the N-terminal sections of reading frames, are reported. Evidences for the involvement of physiological state, signal transduction, and activators in the control of Sm production are presented.