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The gene for an extracellular xylanase from Streptomyces sp. No. 36a was cloned into Streptomyces lividans TK21 using pIJ702 as a vector plasmid. The smallest DNA fragment encoding the xylanase gene and its possible promotor was determined to be a 1.04 kb Sph I-Sac I fragment by sub-cloning studies. This xylanase gene fragment was transferred into the pSK2 series of plasmids and introduced into Streptomyces kasugaensis G3 protoplasts. The cloned xylanase gene was expressed in both S. lividans TK21 and S. kasugaensis G3, and these clones produced and secreted high yields of xylanase into the culture medium. The xylanase production was not detected when a foreign DNA fragment was inserted into the Bcl I site locating in the xylanase gene fragment.

Two new aminoglycoside antibiotics, sporaricins C and D have been isolated from the culture broth of Saccharopolyspora hirsuta subsp. kobensis, which produced sporaricins A and B. The structures of sporaricins C and D have been determined to be 4-N-carbamoyl-glycylsporaricin B and 4-N-formylglycylsporaricin B, respectively. Sporaricins C and D are active against Gram-negative and Gram-negative bacteria including aminoglycoside-resistant strains.

Streptomyces sannanensis KC-7038 used for the production of sannamycins A and B has also produced another antibiotic sannamycin C, in the culture broth. Physico-chemical characterization revealed that sannamycin C is a new aminoglycoside antibiotic having 6-N-methylpurpurosamine C and 2-deoxy-3-epi-fortamine. Its 4-N-glycyl derivative indicated inhibitory activity against Gram-positive and Gram-negative bacteria containing aminoglycoside resistant strains.

Two new carbapenem antibiotics, carpetimycins C and D have been isolated from the culture broth of Streptomyces sp. KC-6643, which produced carpetimycins A and B. The structures of carpetimycins C and D have been determined to be (5R,6R)-3-[2-acetamidoethyl-(R)-sulfinyl]-6-(1-hydroxy-1-methylethyl) -7-oxo-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylic acid and (5R,6R)-3-[2-acetamidoethyl-(R)-sulfinyl]-6-(1-hydroxysulfonyloxy-1 -methylethyl)-7-oxo-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylic acid, respectively. Studies on the fermentation, isolation and physico-chemical properties of these antibiotics are also described.

Two new aminoglycoside antibiotics, sporaricins A (C17H35N5O5) and B (C15H32N4O4) produced by a rare actinomycetales, Saccharopolyspora hirsuta subsp. kobensis have been isolated by column chromatography on a cation-exchange resin. Sporaricin A is highly active against Gram-positive and Gram-negative bacteria including aminoglycoside-resistant strains.