Abstract: Antibiotic 10381a1, wherein R is hydrogen, is a cytosine-containing antibiotic producible by culturing the novel microorganism Streptomyces arginensis in an aqueous medium and isolation thereof. Derivatives wherein R is a C1 to C3 alkyl ester of antibiotic 10381a1, are also disclosed along with the pharmaceutically acceptable salts of both the native and esterified forms. Antibiotic 10381a1 inhibits the growth of selected species of yeast, fungi and bacteria. This invention also relates to a novel process for the preparation of the antibiotics 10381b and to a method of using antibiotics 10381b to promote growth in meat-producing animals. These antibiotics are also obtained by the fermentation of a nutrient medium with the novel microorganism Streptomyces arginensis and are active against selected species of bacteria.

Abstract: Antibiotic 10381a.sub.1, wherein R is hydrogen, is a cytosine-containing antibiotic producible by culturing the novel microorganism Streptomyces arginensis in an aqueous medium and isolation thereof. Derivatives wherein R is a C.sub.1 to C.sub.3 alkyl ester of antibiotic 10381a.sub.1, are also disclosed along with the pharmaceutically acceptable salts of both the native and esterified forms. Antibiotic 10381a.sub.1 inhibits the growth of selected species of yeast, fungi and bacteria. This invention also relates to a novel process for the preparation of the antibiotics 10381b and to a method of using antibiotics 10381b to promote growth in meat-producing animals. These antibiotics are also obtained by the fermentation of a nutrient medium with the novel microorganism Streptomyces arginensis and are active against selected species of bacteria.

Abstract: Antibiotic 10381a.sub.1, wherein R is hydrogen, is a cytosine-containing antibiotic producible by culturing the novel microorganism Streptomyces arginensis in an aqueous medium and isolation thereof. Derivatives wherein R is a C.sub.1 to C.sub.3 alkyl ester of antibiotic 10381a.sub.1, are also disclosed along with the pharmaceutically acceptable salts of both the native and esterified forms. Antibiotic 10381a.sub.1 inhibits the growth of selected species of yeast, fungi and bacteria. This invention also relates to a novel process for the preparation of the antibiotics 10381b and to a method of using antibiotics 10381b to promote growth in meat-producing animals. These antibiotics are also obtained by the fermentation of a nutrient medium with the novel microorganism Streptomyces arginensis and are active against selected species of bacteria.

Abstract: Antibiotic 10381a.sub.1, wherein R is hydrogen, is a cytosine-containing antibiotic producible by culturing the novel microorganism Streptomyces arginensis in an aqueous medium and isolation thereof. Derivatives wherein R is a C.sub.1 to C.sub.3 alkyl ester of antibiotic 10381a.sub.1, are also disclosed along with the pharmaceutically acceptable salts of both the native and esterified forms. Antibiotic 10381a.sub.1 inhibits the growth of selected species of yeast, fungi and bacteria. This invention also relates to a novel process for the preparation of the antibiotics 10381b and to a method of using antibiotics 10381b to promote growth in meat-producing animals. These antibiotics are also obtained by the fermentation of a nutrient medium with the novel microorganism Streptomyces arginensis and are active against selected species of bacteria.

Abstract: Antibiotic 10381a.sub.1, wherein R is hydrogen, is a cytosine-containing antibiotic producible by culturing the novel microorganism Streptomyces arginensis in an aqueous medium and isolation thereof. Derivatives wherein R is a C.sub.1 to C.sub.3 alkyl ester of antibiotic 10381a.sub.1, are also disclosed along with the pharmaceutically acceptable salts of both the native and esterified forms. Antibiotic 10381a.sub.1 inhibits the growth of selected species of yeast, fungi and bacteria. This invention also relates to a novel process for the preparation of the antibiotics 10381b and to a method of using antibiotics 10381b to promote growth in meat-producing animals. These antibiotics are also obtained by the fermentation of a nutrient medium with the novel microorganism Streptomyces arginensis and are active against selected species of bacteria.

Abstract: Antibiotic U-66,026 is produced in a fermentation under controlled conditions using the microorganism Alcaligenes sp., NRRL B-15269. Enhanced fermentation of titers U-66,026 are obtained when Alcaligenes sp., NRRL B-15269, is cultivated in mixture with Streptomyces plicatus strain 395, NRRL 15273.Antibiotic U-66,026 is a useful antibiotic which has antifungal activity.

Abstract: Novel and useful antibiotics designated 273a.sub.1.spsb..alpha. and 273a.sub.1.spsb..beta. can be produced in a fermentation using Streptomyces paulus, strain 273, NRRL 12251. These antibiotics are active against various Gram-positive bacteria. Also, these antibiotics are, advantageously, soluble in aqueous solutions.

Abstract: Novel and useful ribonucleotides of analogs of the well known antibiotics lincomycin and clindamycin. These ribonucleotides are unexpectedly highly active against Streptococcus hemolyticus and Staphylococcus aureus in vivo.

Abstract: Novel and useful ribonucleotides of analogs of the well known antibiotics lincomycin and clindamycin. These ribonucleotides are unexpectedly highly active against Streptococcus hemolyticus and Staphylococcus aureus in vivo. These ribonucleotides are prepared by using resting cell or cell-free extracts of Streptomyces rochei, NRRL 3533, or cell-free extracts of Streptomyces coelicolor, NRRL 3532.

Abstract: Novel and useful ribonucleotides of analogs of the well known antibiotics lincomycin and clindamycin. These ribonucleotides are unexpectedly highly active against Streptococcus hemolyticus and Staphylococcus aureus in vivo.

Abstract: A process for treating a protozoan disease, for example, malaria, by the systemic administration to a subject hosting a malarial parasite of the 3-(5'-ribonucleotide) of a novel analog of the well-known antibiotics lincomycin and clindamycin. The analogs are prepared by condensing a cyclic acid with a sugar amine. The 3-ribonucleotides of these analogs can be prepared by microbiological transformation procedures.

Abstract: Disclosed and claimed is an improved fermentation process for preparing the known antibiotic U-43,120, herein referred to as paulomycin. Also disclosed and claimed are the novel and useful antibiotics paulomycin A and paulomycin B.

Abstract: Antibiotic acanthomycin (U-53,827) produced by the controlled fermentation of the microorganism Streptomyces espinosus subsp. acanthus, NRRL 11081. This antibiotic and its base addition salts are active against Gram-positive bacteria. Accordingly, they can be used in various environments to eradicate or control such bacteria.

Abstract: Microbiological process for preparing the known antibiotics, antibiotic A-396-1 and L-dihydrophenylalanine, by use of the new microorganism Streptomyces lemensis, NRRL 8170 using controlled fermentation conditions. These antibiotics are active against Gram-positive and Gram-negative bacteria. Accordingly, they can be used in various environments to eradicate or control such bacteria.

Abstract: Microbiological process for preparing the known antibiotics, antibiotic A-396-1 also known as U-50,147 and L-dihydrophenylalanine also known as U-51,748, by use of the new microorganism Streptomyces lemensis, NRRL 8170 using controlled fermentation conditions. These antibiotics are active against Gram-positive and Gram-negative bacteria. Accordingly, they can be used in various environments to eradicate or control such bacteria.

Abstract: Feldamycic acid, having the structure ##STR1## is obtained by the hydrolysis of the antibiotic feldamycin (U-48,266) and can be coupled with nutritional amino acids to give peptides, useful as nutritional supplements.

Abstract: Antibiotic U-51,640 produced by the controlled fermentation of the microorganism Streptomyces ficellus Dietz, sp. n., NRRL 8067. This antibiotic and its acid addition salts are active against Gram-positive and Gram-negative bacteria. Accordingly, they can be used in various environments to eradicate or control such bacteria.

Abstract: New antibiotic U-47,929 produced by the controlled fermentation of the new microorganism Streptomyces ficellus Dietz, sp. n., NRRL 8067. This antibiotic and its acid-addition salts are active against Gram-positive bacteria. Accordingly, they can be used in various environments to eradicate or control such bacteria.

Abstract: New antiviral agent U-50,228 and derivatives thereof, produced by the controlled fermentation of the known microorganism Streptomyces platensis var. clarensis var nova, NRRL 8035. This antiviral agent and its derivatives are active against DNA-viruses, for example, the Herpes virus and, thus, can be used to control such virus where its presence is not desired. For example, U-50,228 and its derivatives can be used to swab laboratory benches and equipment in a virology laboratory to eliminate the presence of Herpes virus.

Abstract: New antibiotic U-48,266 produced by the controlled fermentation of the microorganism Streptomyces ficellus Dietz, sp. n., NRRL 8067. This antibiotic and its acid and base addition salts are active against Gram-positive and Gram-negative bacteria. Accordingly, they can be used in various environments to eradicate or control such bacteria.