Abstract: Antibiotic A-33853 is produced by submerged, aerobic fermentation of a new Streptomyces sp. NRRL 12068. The antibiotic has shown antibacterial activity against Staphylococcus and Streptococcus species which are penicillin resistant. In addition, the antibiotic has shown antirival and antitrichomonal activity in vitro.

Abstract: Antibiotic A-32256 which is produced by submerged, aerobic fermentation of a Streptomyces sp. NRRL 12067. The antibiotic has shown antibacterial activity against Staphylococcus and Streptococcus and various anaerobic species. In addition, the antibiotic has shown antitrichomonas activity in vitro, as well as activity for improving ruminant feed efficency and as a mosquito larvacide.

Abstract: Antibiotic A-33853 is produced by submerged, aerobic fermentation of a new Streptomyces sp. NRRL 12068. The antibiotic has shown antibacterial activity against Staphylococcus and Streptococcus species which are penicillin resistant. In addition, the antibiotic has shown antiviral and antitrichomonal activity in vitro.

Abstract: A-40104 antibiotic complex, comprising active factors A, B, C, and D, produced by submerged aerobic fermentation of Clitopilus pseudo-pinsitus. Individual factors A, B, and C have been isolated. A-40104 factor C is the known antibiotic pleuromutilin. A-40104 factors A and B are novel antibiotics related to pleuromutilin. A-40104 factor A, the major new factor, is the D-xylose acetal derivative of pleuromutilin. A-40104 factors A and B, their 19,20-dihydro derivatives and the per(C.sub.2 -C.sub.6)alkanoyl derivatives of factors A and B and of their 19,20-dihydro derivatives are active against gram-positive and gram-negative bacteria, anaerobic bacteria, and Mycoplasma.

Abstract: A refillable column for chromatography at elevated pressure is described comprised of a cylinder connected on both ends to a coupling having internal threads and an annular shoulder at the internal terminus of the threads. A plug having external threads is disposed in said coupling and sealed against the shoulder of the coupling. An axial hole communicates between the top and bottom of the plug. The column can be packed, emptied and repacked repeatedly.

Abstract: A-40104 antibiotic complex, comprising active factors A, B, C, and D, produced by submerged aerobic fermentation of Clitopilus pseudo-pinsitus. Individual factors, A, B, and C have been isolated. A-40104 factor C is the known antibiotic pleuromutilin. A-40104 factors A and B are novel antibiotics related to pleuromutilin. A-40104 factor A, the major new factor, is the D-xylose acetal derivative of pleuromutilin. A-40104 factors A and B, their 19,20-dihydro derivatives and the per(C.sub.2 -C.sub.6)alkanoyl derivatives of factors A and B and of their 19,20-dihydro derivatives are active against gram-positive and gram-negative bacteria, anaerobic bacteria, and Mycoplasma.

Abstract: Antibiotic A-35512 complex, comprising microbiologically active, related factors A, B, C, E and H, is produced by submerged aerobic fermentation of Streptomyces candidus NRRL 8156. The individual A-35512 factors are separated and isolated by chromatography. The A-35512 antibiotics are antibacterial and growth-promoting agents and increase feed-utilization efficiency in animals. In addition, A-35512 factor B is useful in the treatment of dental caries and acne.

Abstract: Antibiotic A-35512 complex, comprising microbiologically active, related factors A, B, C, E and H, is produced by submerged aerobic fermentation of Streptomyces candidus NRRL 8156. The individual A-35512 factors are separated and isolated by chromatography. The A-35512 antibiotics are antibacterial and growth-promoting agents and increase feed-utilization efficiency in animals. In addition, A-35512 factor B is useful in the treatment of dental caries and acne.

Abstract: Antibiotic A-30912 complex, comprising microbiologically active, structurally related factors A, B, C, D, E, F and G, is produced by submerged aerobic fermentation of Aspergillus rugulosus NRRL 8113. The A-30912 factors A, B, C, D, E, F, and G are separated from the A-30912 complex by chromatography. The A-30912 complex and individual factors A, B, C, D, E, F, and G are antifungal agents.

Abstract: Antibiotic A-22082 is produced by submerged aerobic fermentation of Aspergillus nidulans NRRL 8112. Antibiotic A-22082 is an antifungal agent.

Abstract: Antibiotic mixture A-26771, comprising microbiologically active factors A, B and C, produced by fermentation of Penicillium turbatum Westling NRRL 5630, and isolation and separation of the individual factors thereof by extraction, chromatography and crystallization. The A-26771 mixture and factors A, B and C thereof have antifungal and broadspectrum antibacterial activity; factors A and C also have antiviral activity.

Abstract: Antibiotic mixture A-26771, comprising microbiologically active factors A, B and C, produced by fermentation of Penicillium turbatum Westling NRRL 5630, and isolation and separation of the individual factors thereof by extraction, chromatography and crystallization. The A-26771 mixture and factors A, B and C thereof have antifungal and broad-spectrum antibacterial activity; factors A and C also have antiviral activity.