[structure: see text] Laboratory cultures of an undescribed streptomycete obtained from the surface of a British Columbia lichen produce uncialamycin (1), a new enediyne antibiotic. The structure of uncialamycin (1) has been elucidated by analysis of spectroscopic data. Uncialamycin (1) exhibits potent in vitro antibacterial activity against gram-positive and gram-negative human pathogens, including Burkholderia cepacia, a major cause of morbidity and mortality in patients with cystic fibrosis.

Four butenolides, ramariolides A-D (1-4), have been isolated from the fruiting bodies of the coral mushroom Ramaria cystidiophora. Their structures were elucidated by analysis of 1D and 2D NMR data and a single-crystal X-ray diffraction analysis of 1, and their absolute configurations were established using Mosher's method. The major metabolite, ramariolide A (1), which contains an unusual spiro oxiranebutenolide moiety, showed in vitro antimicrobial activity against Mycobacterium smegmatis and Mycobacterium tuberculosis.

Antibiotics U 1200 Uncialamycin, a New Enediyne Antibiotic -[with potent in vitro activity against Gram-positive and Gram-negative human pathogens]. -(DAVIES*, J.; WANG, H.; TAYLOR, T.; WARABI, K.; HUANG, X.-H.; ANDERSEN, R. J.; Org. Lett. 7 (2005) 23, 5233-5236; Dep. Microbiol. Immunol., Univ. British Columbia, Vancouver, B. C. V6T 1Z1, Can.; Eng.) -R. Steudel 13-207