Abstract: The invention provides isolated nucleic acid compounds encoding the glycosyltransferase protein GtfD of Amycolatopsis orientalis. Also provided are vectors carrying the gtfD gene, transformed heterologous host cells for expressing the GtfD protein, and methods for producing glycopeptide compounds using the cloned gtfD gene.

Abstract: The invention provides isolated nucleic acid compounds encoding the glycosyltransferase protein GtfC of Amycolatopsis orientalis. Also provided are vectors carrying the gtfC gene, transformed heterologous host cells for expressing the GtfC protein, and methods for producing glycopeptide compounds using the cloned gtfC gene.

Abstract: The present invention comprises an .about.0.8 kb Sac II restriction fragment of phage FP43, which confers the pin phenotype. The present invention allows transduction at high m.o.i. using the phage FP43 high frequency transduction system.

Abstract: The present invention is a method for isolating antibiotic biosynthetic genes. To practice the method, an antibiotic resistance-conferring DNA segment is labelled and used as a probe to find, via DNA hydridization, homologous DNA in a genetic library which comprises chromosomal and plasmid DNA of an antibiotic-producing organism. Individual vectors of the genetic library which hybridize to the antibiotic resistance-conferring gene, and which comprise .about.1-45 kb of contiguous DNA from the antibiotic-producing organism, which also comprise an antibiotic biosynthetic gene. The present method is exemplified by using the erythromycin resistance-conferring gene of Streptomyces erythreus to clone the erythromycin biosynthetic pathway from the same organism. The erythromycin biosynthetic pathway isolated with the present method synthesizes erythromycin when introduced into S. lividans TK23.

Abstract: New macrocin and lactenocin ester derivatives of the formula: ##STR1## wherein R is formyl or hydroxymethyl; R.sup.1 is hydrogen, acetyl or propionyl; R.sup.2 is hydrogen or ##STR2## and R.sup.3 is hydrogen, acetyl, propionyl, n-butyryl or isovaleryl; provided that one of R.sup.1 or R.sup.3 must be other than hydrogen; and the acid addition salts thereof; prepared by bioconversion of macrocin or lactenocin with an acylating enzyme system produced by Streptomyces thermotolerans strains, have improved activity against Mycoplasma species.

Abstract: New macrocin and lactenocin ester derivatives of the formula: ##STR1## wherein R is formyl or hydroxymethyl; R.sup.1 is hydrogen, acetyl or propionyl; R.sup.2 is hydrogen or ##STR2## and R.sup.3 is hydrogen, acetyl, propionyl, n-butyryl or isovaleryl; provided that one of R.sup.1 or R.sup.3 must be other than hydrogen; and the acid addition salts thereof; prepared by bioconversion of macrocin or lactenocin with an acylating enzyme system produced by Streptomyces thermotolerans strains, have improved activity against Mycoplasma species.

Abstract: 23-Demycinosyltylosin (DMT) which has the formula: ##STR1## 20-dihydro-DMT, specified acyl ester derivatives, and their acid addition salts are useful antibacterial agents. Improved methods of making 5-O-mycaminosyltylonolide (OMT) and 20-dihydro-OMT by mild acid hydrolysis of DMT and 20-dihydro-DMT, respectively, are included.

Abstract: 2'"-O-demethylmacrocin (DOMM) which has the formula: ##STR1## 20-dihydro-DOMM, 2'"-O-demethyllactenocin (DOML), 20-dihydro-DOML, specified acyl ester derivatives, and their acid addition salts are useful antibacterial agents.

Abstract: A new microorganism, Streptomyces fradiae NRRL 12201, which produces mycarosyltylactone (5-O-mycarosyl-20-dihydro-20,23-dideoxytylonolide) and a process for preparing tylactone (20-dihydro-20,23-dideoxytylonolide) and mycarosyltylactone by submerged aerobic fermentation of this microorganism, or a mycarosyltylactone-producing mutant or recombinant thereof, are provided.

Abstract: 23-Demycinosyltylosin (DMT) which has the formula: ##STR1## 20-dihydro-DMT, specified acyl ester derivatives, and their acid addition salts are useful antibacterial agents. Improved methods of making 5-O-mycaminosyltylonolide (OMT) and 20-dihydro-OMT by mild acid hydrolysis of DMT and 20-dihydro-DMT, respectively, are included.

Abstract: 20-Dihydro-20-deoxy-23-demycinosyltylosin (DH-DO-DMT), 20-dihydro-20-deoxy-5-O-mycaminosyltylonolide (DH-DO-OMT), specified acyl ester derivatives, and their acid addition salts are useful intermediates and antibacterial agents. Methods of preparing DH-DO-DMT and DH-DO-OMT by fermentation of Streptomyces fradiae and the microorganism S. fradiae ATCC 31733 are included.

Abstract: 2'"-O-demethylmacrocin (DOMM) which has the formula: ##STR1## 20-dihydro-DOMM, 2'"-O-demethyllactenocin (DOML), 20-dihydro-DOML, specified acyl ester derivatives, and their acid addition salts are useful antibacterial agents.

Abstract: A process for preparing tylactone (20-dihydro-20,23-dideoxytylonolide), which has the formula: ##STR1## by submerged aerobic fermentation of Streptomyces fradiae NRRL 12188 or a tylactone-producing mutant or recombinant thereof is provided.

Abstract: Tylactone (20-dihydro-20,23-dideoxytylonolide), which has the formula: ##STR1## and specified acyl ester derivatives thereof are useful intermediates in the preparation of macrolide antibiotics.

Abstract: 23-De(mycinosyloxy)tylosin (DMOT) which has the formula: ##STR1## 20-dihydro-DMOT, specified acyl ester derivatives, and the acid addition salts thereof are useful antibacterial agents. New methods of making 23-deoxy-5-O-mycaminosyltylonolide (DOMT) and 20-dihydro-DOMT by mild acid hydrolysis of DMOT and 20-dihydro-DMOT, respectively, are included.

Abstract: 23-De(mycinosyloxy)tylosin (DMOT) which has the formula: ##STR1## 20-dihydro-DMOT, specified acyl ester derivatives, and the acid addition salts thereof are useful antibacterial agents. New methods of making 23-deoxy-5-O-my-caminosyltylonolide (DOMT) and 20-dihydro-DOMT by mild acid hydrolysis of DMOT and 20-dihydro-DMOT, respectively, are included.

Abstract: 23-Demycinosyltylosin (DMT) which has the formula: ##STR1## 20-dihydro-DMT, specified acyl ester derivatives, and their acid addition salts are useful antibacterial agents. Improved methods of making 5-O-mycaminosyltylonolide (OMT) and 20-dihydro-OMT by mild acid hydrolysis of DMT and 20-dihydro-DMT, respectively, are included.

Abstract: 20-Dihydro-20-deoxy-23-demycinosyltylosin (DH-DO-DMT), 20-dihydro-20-deoxy-5-O-mycaminosyltylonolide (DH-DO-OMT), specified acyl ester derivatives, and their acid addition salts are useful intermediates and antibacterial agents. Methods of preparing DH-DO-DMT and DH-DO-OMT by fermentation of Streptomyces fradiae and the microorganism S. fradiae ATCC 31733 are included.

Abstract: A method of obtaining Streptomyces protoplasts which are able to regenerate viable cells with high efficiency is disclosed. The method involves growing Streptomyces cells to a particular physiological state, the transition phase between the exponential and stationary growth phases, and then forming protoplasts. The physiological state of the cells at the time of protoplast formation is crucial for efficient cell regeneration. Protoplasts obtained by this method enhance the use of protoplast-fusion techniques to effect genetic exchange within the genus Streptomyces, thereby facilitating the construction of hybrid or recombinant Streptomyces strains with useful properties.