Antibiofilm activity on Candida albicans and mechanism of action on biomembrane models of the antimicrobial peptide Ctn[15-34]

Aguiar, Francisca Lidiane Linhares de; Santos, Nuno C.; Cavalcante, Carolina Sidrim de Paula; Andreu Martínez, David; Baptista, Gandhi Radis; Gonçalves, Sónia

doi:http://dx.doi.org/10.3390/ijms21218339

Antibiofilm activity on Candida albicans and mechanism of action on biomembrane models of the antimicrobial peptide Ctn[15-34]

License

Citation

Aguiar FLL, Santos NC, Cavalcante CSPC, Andreu D, Baptista GR, Gonçalves S. Antibiofilm activity on Candida albicans and mechanism of action on biomembrane models of the antimicrobial peptide Ctn[15-34]. Int J Mol Sci. 2020; 21(21):8339. DOI: 10.3390/ijms21218339

Abstract

Ctn[15-34], the C-terminal fragment of crotalicidin, an antimicrobial peptide from the South American rattlesnake Crotalus durissus terrificus venom, displays remarkable anti-infective and anti-proliferative activities. Herein, its activity on Candida albicans biofilms and its interaction with the cytoplasmic membrane of the fungal cell and with a biomembrane model in vitro was investigated. A standard C. albicans strain and a fluconazole-resistant clinical isolate were exposed to the peptide at its minimum inhibitory concentration (MIC) (10 µM) and up to 100 × MIC to inhibit biofilm formation and its eradication. A viability test using XTT and fluorescent dyes, confocal laser scanning microscopy, and atomic force microscopy (AFM) were used to observe the antibiofilm effect. To evaluate the importance of membrane composition on Ctn[15-34] activity, C. albicans protoplasts were also tested. Fluorescence assays using di-8-ANEPPS, dynamic light scattering, and zeta potential measurements using liposomes, protoplasts, and C. albicans cells indicated a direct mechanism of action that was dependent on membrane interaction and disruption. Overall, Ctn[15-34] showed to be an effective antifungal peptide, displaying antibiofilm activity and, importantly, interacting with and disrupting fungal plasma membrane.