Fungicidal effect of piscidin on Candida albicans: pore formation in lipid vesicles and activity in fungal membranes.
Piscidin, a 22-residue cationic peptide isolated from the mast cells of hybrid striped bass, has potent antimicrobial activities. In the present study, we investigated the fungicidal activity and mode of action of piscidins. Fungicidal and hemolytic assays were examined in order to assess their potency and toxicity, respectively. The results showed that fungicidal and hemolytic activities were higher for piscidin 1 (P1) than piscidin 3 (P3). Additionally, the abilities to permeabilize the model phospholipids membranes were also higher for P1 than P3, which were consistent with the biological activities of P1 and P3. These results suggest that the biological action of the peptides may be carried out through the lipid membrane. To understand the fungicidal properties of P1, we focused on a membrane-active mechanism of the peptide by in vivo testing against Candida albicans as the model organism. Flow cytometric analysis by using bis-(1,3-dibutylbarbituric acid) trimethine oxonol [DiBAC(4)(3)] and protoplast regeneration experiments showed that P1 caused fungal membrane damage. Furthermore, fluorescence analysis, using 1,6-diphenyl-1,3,5-hexatriene, revealed that these peptides created pores in fungal membranes. Thus, the present study demonstrated that piscidins exert their fungicidal effects by disrupting fungal membrane through pore formation.
Sung
Woo Sang
WS
School of Life Sciences & Biotechnology, College of Natural Sciences, Kyungpook National University, 1370 Sankyukdong, Puk-ku, Daegu 702-701, Republic of Korea.
Lee
Juneyoung
J
Lee
Dong Gun
DG
D000935:Antifungal Agents / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides / Q000494:pharmacology*; D002176:Candida albicans / Q000187:drug effects* / Q000648:ultrastructure; D002462:Cell Membrane / Q000187:drug effects; D002473:Cell Wall / Q000187:drug effects; D004912:Erythrocytes / Q000187:drug effects; D029941:Fish Proteins / Q000494:pharmacology*; D005434:Flow Cytometry; D005452:Fluoresceins / Q000378:metabolism; D005454:Fluorescence Polarization; D005658:Fungi / Q000187:drug effects* / Q000648:ultrastructure; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D008055:Lipids / Q000737:chemistry*; D008564:Membrane Potentials / Q000187:drug effects; D008567:Membranes, Artificial; D008826:Microbial Sensitivity Tests; D016062:Porosity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D000935:Antifungal Agents; D023181:Antimicrobial Cationic Peptides; D029941:Fish Proteins; D005452:Fluoresceins; D008055:Lipids; D008567:Membranes, Artificial; C449802:moronecidin protein, Morone saxatilis; C007740:fluorexon