Antifungal activity of spider venom-derived peptide lycosin-I against Candida tropicalis

Publication date: Available online 27 August 2018Source: Microbiological ResearchAuthor(s): Li Tan, Le Bai, Ling Wang, Lagu He, Guangdi Li, Wenhan Du, Ting Shen, Zheyi Xiang, Jiali Wu, Zhonghua Liu, Min HuAbstractCandida species are a major cause of human mucosal and deep tissue fungal infections, but few antifungal treatments are available. Here, we showed that lycosin-I, a peptide isolated from venom of the spider Lycosa singoriensis, acted as a potent antifungal inhibitor against Candida species. The MIC50 values of lycosin-I reached 8 µg/mL to treat fluconazole-susceptible and fluconazole-resistant C. tropicalis isolates. Time-kill kinetics assays revealed that after a 2-hour exposure, lycosin-I reduced colony-forming units/mL in fluconazole-susceptible and fluconazole-resistant C. tropicalis isolates approximately 70%. Furthermore, salinity tolerance assays suggested that even in the presence of Mg2+, lycosin-I maintained its potent antifungal ability at a high concentration. When the concentration of lycosin-I was increased from 1 × MIC to 8 × MIC, a significant decrease of the biofilm metabolic activity was observed in both fluconazole-susceptible and fluconazole-resistant C. tropicalis isolates. Moreover, the biofilm inhibitory concentration 50 (BIC50) and the biofilm eradicating concentration 50 (BEC50) were approximately 32 µg/mL and 128 µg/mL, respectively. Confocal laser scanning microscopy showed the localization of CY5-labeled lycosin-I mainly...
Source: Microbiological Research - Category: Infectious Diseases Source Type: research