Peptides with differential cytolytic activity from skin secretions of the lemur leaf frog Hylomantis lemur (Hylidae: Phyllomedusinae)

Two peptides with differential cytolytic activity against bacteria, a fungus pathogenic to amphibians, and mammalian cells were isolated from norepinephrine-stimulated skin secretions of the Lemur leaf frog Hylomantis lemur Boulenger, 1882. Dermaseptin-L1 (GLWSKIKEAAKAAGKAALNAVTGLVNQGDQPS) was active against the Gram-negative bacterium Escherichia coli (MIC = 8 mu M) but inactive against the Gram-positive bacterium Staphylococcus aureus. This peptide inhibited growth of zoospores of the chytrid fungus Batrachochytrium dendrobatidis at concentrations above 25 mu M but did not completely inhibit growth at 100 mu M. Phylloseptin-L1 (LLGMIPLAISAISALSKL.NH2) was active against S. aureus (MIC = 8 mu M) but was inactive against E coli. This peptide also inhibited growth of R dendrobatidis zoospores at concentrations above 25 mu M with complete inhibition at 100 mu M. Dermaseptin-L1 showed selective cytolytic activity against HepG2 human hepatoma-derived cells (LC50 = 45 mu M) compared with human erythrocytes (LC50 = 200 M) whereas phylloseptin-L1 was approximately equipotent against both HepG2 cells (LC50 = 35 M) and erythrocytes (LC50 = 40 mu M). (C) 2007 Elsevier Ltd. All rights reserved.