Tymchyk O. Physical, chemical and biological properties of landomycin Е and its production by Streptomyces globisporus 3-1.

The dissertation is dedicated to research of physical, chemical and biological properties of a new antitumur antibiotic landomycin Е and its production by strain S. globisporus 3-1. The complete medium with a corn flour and cultivation parameters in laboratory fermenter are proposed as the basis for the further optimization of cultivation conditions of strain 3-1. Landomycin Е is intensively synthesized in exponential stage of culture growth simultaneously with accumulation of mycelium biomass, assimilation of glucose and absorption of dissolving oxygen. Glucose in concentration of 1 - 4 % does not affect landomycin Е biosynthesis. It was established, that a long cultivation of strain 3-1 on the soya medium, and also a long storage of landomycin Е in ethanol caused dehydratation of antibiotic and changed its the structure properties. Examination of toxicity and mutagenic activity of any antibiotic is a necessary condition of its study. The received results can be used for establishment of a therapeutic doze of a preparation. For the first time it was shown the toxicity of landomycin Е on laboratory animals LD50=75 mg/kg, and a weak level of mutageniсity - on S. typhimurium ТА98 and ТА100 strains. Native form of landomycin Е is slight more active in against Grampositive microorganisms. The high sensitivity of mycelium of strain 3-1 and spores of strain Spo1 to lethal action of streptomycin and landomycin E accordingly was shown. Concentration of the given antibiotics of 5 g/ml reduced a survial level of mentioned above strains on 106,5. The resistance of strain 3-1 to UV-radiation and high sensivity of strain Spo1 to ultra-violet radiation and methylmetanesulphonate were established. These results indicated on damage of reparation systems of the pyrimidine dimers and alkilated bases in the strain Spo1.