Gliotoxin is Antibacterial to Drug-resistant Piscine Pathogens

By activity-guided fractionation, gliotoxin was isolated as an antibacterial metabolite of the fungus Penicillium decumbens which was derived from the jellyfish Nemopilema nomurai. Gliotoxin was further evaluated for antibacterial activity against several piscine and human MDR (multidrug resistance) pathogens. Gliotoxin showed significant antibacterial activity against Gram-positive piscine pathogens such as Streptococcus iniae FP5228, Streptococcus iniae FP3187, Streptococcus parauberis FP3287, Streptococcus parauberis SPOF3K, S. parauberis KSP28, and Lactococcus garvieae FP5245. Gliotoxin showed strong activity especially against S. parauberis SPOF3K and S. iniae FP5228, which are resistant to oxytetracycline. It is noteworthy that gliotoxin effectively suppressed streptococci which are the major pathogens for piscine infection and mortality in aquaculture industry. Gliotoxin also showed strong antibacterial activity against multidrug-resistant human pathogens (MDR) including Enterococcus faecium 5270 and MRSA (methicillin-resistant Staphylococcus aureus) 3089.

Compounds from a jellyfish-derived fungus Aspergillus fumigates

Six compounds were isolated from the secondary metabolites of the jellyfish-derived fungus Aspergillus fumigates, whose structures were identified by chemical methods and spectroscopic analysis as pseurotin F1 (1), azaspirofurans B (2), (22E, 24R)-24-methyl-5α-cholesta-7,22-diene-3β,5,6β-triol (3), 5α,8α-epidioxyergosta-6,22-dien-3β-o1 (4), cyclo-(L-Pro-L-Tyr) (5), fumitremorgin C (6). The compounds 1 - 5 were isolated from the fungus Aspergillus fumigates for the first time. The isolated compounds (1 - 6) were evaluated for antibiotic activity and cytotoxicity against six bacterial strains and ten human tumor cell lines, respectively.