Compounds with antiviral, antineoplastic, antifungal and antibacterial activities will be identified in marine species and their structures will be assigned. These include new components of the didemnin (antiviral, antineoplastic) and eudistomin (antiviral) complexes and an antineoplastic compound from Ecteinascidia turbinata, all from tunicates, as well as compounds from other tunicates and sponges. In addition, metabolites and quantitation of didemnin B will be studied in connection with its forthcoming clinical trials in cancer patients. Structures of a number of antibiotics will also be studied. These include the antifungal polyenes hamycin, aureofungin, and candimycin, as well as the non-polyenic antifungal macrolide desertomycin, the phospholipids quebemycin and 409 complex (antibacterial), the aromatic crisamicin (antineoplastic), and ficellomycin. Peptide antibiotics to be studied include saramycetin (antifungal), CC-1014B (cytotoxic), berninamycins A and B (antibacterial), antiamoebin, emerimicin, zervamicin, and alamethicin (all antibacterial and pore-forming). Bioactive compounds (antiviral) present in insects will also be identified and structural studies will be carried out on a Legionella pigment and a Pseudomonas growth factor.