The activity of a specific enzymatic complex, macrotetralide synthase, is observed at all stages of Streptomyces chrysomallus subsp. macrotetralidi development. Both synthase (esterase) and hydrolase activities of the enzyme may be realized in cell-free homogenate in cultures of different age under different conditions of culturing.
View Article and Find Full Text PDFMol Gen Mikrobiol Virusol
May 1996
Streptomyces producing ionophore antibiotics were searched for in various natural substrata, such as soil, sea water, and coastline sea mud, in many geographical regions. A total of 393 Streptomyces strains were isolated, 308 of which proved to be capable of producing antibiotics; 135 of these contained water-insoluble antibiotically active substances in the mycelium. Studies by radioindication, spectrophotometry, and potentiometry demonstrated that these partially purified hydrophobic antibiotics possessed ionophore properties.
View Article and Find Full Text PDFThe ionophoretic macrotetrolide antibiotics selective to monovalent cations K+ and mainly to NH4+ were determined during the lag period of culture growth. At this stage the cells contain the maximal amounts of Na+ and K+. Macrotetrolides, whose selectivity to Na+ and K+ varies, can regulate the intracellular content of these cations by participating in the cation transport.
View Article and Find Full Text PDFThe dynamics of calcium accumulation by cells in batch cultures and by washed cells was defined with a radiotracer procedure for Streptomyces chrysomallus var. macrotetrolidi producing ionophore macrotetrolide antibiotics. It was shown that macrotetrolides added to the cultivation medium could regulate intracellular contents of calcium by participating in cation transport.
View Article and Find Full Text PDFInfluence of various solvents on the content of macrotetrolides during their prolonged storage in solution was shown. Under the conditions of room temperature 90 per cent acetone induced hydrolysis of polyether antibiotics. 90 per cent ethanol and dry chloroform induced respectively slight and intensive cyclization of linear precursors (oxyacids).
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