Abstract: A method of increasing the yield of a desired product, such as an antibiotic, by an organism which normally must first become inducibly resistant to that product before it can produce the product in maximum yields comprises producing constitutively resistant cells of the organism by supplementing a culture of the organism with an agent in which only cells able to specifically modify the 23S ribosomal RNA constitutively, rather than inducibly, survive thereby producing an organism in which the resistance to the product is expressed without the need for activation by the induction process; followed by purification and utilization of that organism for increased product production.

Abstract: Actinomadura Kijaniata nov. sp produces a novel antibiotic which we have designated kijanimicin. The antibiotic or cationic salts thereof exhibit anti-acne, antitumor, antimalarial, antibacterial and anti-inflammatory activity.

Abstract: The Antiboitic AR-5 complex is elaborated by a novel species of the Micromonospora; namely, Micromonospora polytrota. The microorganism also elaborates a number of minor components including the gentamicin complex and a complex of anthroquinone antibiotics.

Abstract: Antibiotic compounds of the formula: ##STR1## wherein R' is ##STR2## or --CH.sub.2 OH, and the non-toxic pharmaceutically acceptable acid addition salts thereof, are produced by culturing Streptomyces flocculus NRRL 11459. Techniques for isolating the compounds are also described. Cirramycin A.sub.1 and cirramycin B are coproduced.

Abstract: The AR-5-3 Complex consisting of four macrolide antibiotics is elaborated by a mutant strain of Micromonospora polytrota. The antibiotics exhibit substantial activity against gram positive bacteria in vitro and in vivo.

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: Novel compounds are produced by the fermentation of a nutrient medium with the previously undescribed microorganism Streptomyces avermitilis. They may be isolated by solvent extraction and chromatographic fractionation techniques. The compounds, which are described generically as C-076 have significant parasiticidal activity. The compounds may be included in compositions for the oral or parenteral administration to animals for the treatment of parasitic infections.

Abstract: The Antibiotic AR-5 complex is elaborated by a novel species of the Micromonospora; namely, Micromonospora polytrota. The microorganism also elaborates a number of minor components including the gentamicin complex and a complex of gentamicin antibiotics.

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 novel microorganism species belonging to the genus Micromonospora, i.e. Micromonospora sp. A 11725 is found to be capable of producing novel macrolide antibiotics A 11725 I, A 11725 II and A 11725 III. Novel antibiotics A 11725 Ia and A 11725 IIa are also found to be derived by chemical modification of the antibiotics A 11725 I and A 11725 II, respectively. All of these antibiotics or salts thereof exhibit excellent antibacterial and anti-mycoplasmal activities against various microorganisms such as Staphylococcus or Mycoplasma, and therefore useful for various purposes including medicaments.

Abstract: There are disclosed certain new derivatives of C-076 compounds which have been isolated from the fermentation broth that produced the original C-076 compounds. The compounds retain the C-076 16-membered cyclic backbone, however, the groups attached thereto are considerably modified from the original C-076 compounds. The new compounds have been found to retain the biological activity of the parent C-076 compounds. The compounds are thus potent antiparasitic agents and compositions and methods for such uses are also disclosed.

Abstract: Antibiotic compounds of the formula: ##STR1## wherein R' is ##STR2## or --CH.sub.2 OH, and the non-toxic pharmaceutically acceptable acid addition salts thereof, are produced by culturing Streptomyces flocculus NRRL 11459. Techniques for isolating the compounds are also described. Cirramycin A.sub.1 and cirramycin B are coproduced.

Abstract: A novel antibiotic complex exhibiting antifungal activity is produced by fermenting a novel species of bacteria from the genus Aeromonas, the bacterium being herein designated Aeromonas sp. W-10. The antibiotic complex is comprised of at least three and possibly as many as six components and has been designated Antibiotoc W-10 Complex. Two members of the complex have been isolated in substantially pure form and are designated Antibiotic 20561 and Antibiotic 20562, the antibiotics exhibiting substantial antifungal activity.

Abstract: New tylosin derivatives having at least one acyl group at the 3- and 4"-positions of tylosin, and the acid addition salts thereof, which inhibit the growth of various microorganisms including drug-resistant bacterial isolants and which produce high blood levels through oral administration are produced by a biochemical reaction using the microorganisms of the genus Streptomyces which are selected for their newly-found ability to acylate at least one of the 3- and 4"-positions of macrolide antibiotics; they are recovered from the reacted mixture by conventional methods for recovering macrolide antibiotics.

Abstract: This case relates to a novel process which aids in the isolation and purification of novel compounds which are produced by the microorganism, Streptomyces avermitilis. The process described utilizes a non-aqueous extraction system for purifying crude extracts of the novel compounds. The compounds which are isolated and purified are described generically as C-076 and have significant parasiticidal activity.

Abstract: This case relates to a novel process which aids in the isolation and purification of novel compounds which are produced by the microorganism, Streptomyces avermitilis. The process described herein utilizes a high pressure liquid chromatographic system (HPLC) for the isolation and purification of the active compound. The compounds which are isolated and purified are described generically as C-076 and have significant parasiticidal activity.