| 摘要 |
NEW MATERIAL:Antibiotic KA-6643-A of the formula and its salts. Physical and chemical properties of its sodium salt is as follows: a colorless powder; melting point, gradually decomposing from 145 deg.C; ultraviolet absorption spectra, maximum absorptions at 240 and 288nm and minimum absorption at 265nm; solubility, readily soluble in water, insoluble in acetone, clhoroform, ethyl acetate and petroleum ether. USE:Antibiotic; It shows excellent antibacterial activity against gram-positive and -negative bacteria including ones resistant to beta-lactam antibiotics as well as beta- lactamese inhibition activity. PREPARATION:A bacteria, which belongs to Streptomyces and can produce KA- 6643 substances, e.g., Streptomyces sp. KC-6643 (FERM-4467), is cultured by a usual method employed in the cultivation of actinomycetes and KA-6643-A is collected from the culture medium by an appropriate combination of known separation techniques. |
