Marine microorganisms antibacterial activities

Aziridine alkaloids comprise a rare group of natural products. They are mainly isolated from either microorganisms or plants. They have also been detected in some marine species. Reported activities for purified alkaloids have shown strong antitumor, antibacterial, antimicrobial, and other activities. A wide spectrum of pharmacological activities is associated with this type of alkaloid which extends to selected synthetic derivatives. 

Although historically most useful antibiotics have come from spore forming microorganisms, marine organisms have yielded the candidate antitumor peptide didemnin B [77327-50-0] (2) and cytostatic peptides such as the patellamides (3). Many of the marine peptides have little or no antimicrobial activity. Antibacterial peptides called magainins are found in frog skin (4) and antibacterial proteins called defensins are found in mammalian white blood cells (5). The commercially important insecticidal proteins from Bacillus thuringensis (6) are not discussed herein nor are the numerous peptide siderophores (7,8), which, except for the albomycins (9), are usually not antimicrobial. 

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