Marianna de Carvalho Clímaco1, Yrna Lorena Matos de Oliveira1, Anne Caroline Santos Ramos1, Jucicleide Ramos-de-Souza1, Audrey Rouse Soares Tavares Silva1,2, Sona Jain3, Marilise Brittes Rott4, Ricardo Scher2, Cristiane Bani Correa2, Ana Andrea Teixeira Barbosa5, Silvio Santana Dolabella6. 1. Laboratório de Entomologia e Parasitologia Tropical, Departamento de Morfologia, Universidade Federal de Sergipe, São Cristóvão, Sergipe, 49100-000, Brazil. 2. Laboratório de Biologia e Imunologia de Câncer e Leishmania, Departamento de Morfologia, Universidade Federal de Sergipe, São Cristóvão, Sergipe, Brazil. 3. Programa de Pós-Graduação em Biotecnologia Industrial, Universidade Tiradentes, Aracaju, Sergipe, Brazil. 4. Departamento de Microbiologia, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil. 5. Laboratório de Bacteriologia, Departamento de Morfologia, Universidade Federal de Sergipe, São Cristóvão, Sergipe, 49100-000, Brazil. ana.barbosaufs@yahoo.com.br. 6. Laboratório de Entomologia e Parasitologia Tropical, Departamento de Morfologia, Universidade Federal de Sergipe, São Cristóvão, Sergipe, 49100-000, Brazil. dolabellaufs@gmail.com.
Abstract
PURPOSE: Acanthamoeba spp. are free-living amoebas with worldwide distribution and play an important role as disease-causing agents in humans. Drug inability to completely eradicate these parasites along with their toxic effects suggest urgent need for new antimicrobials. Nisin is a natural antimicrobial peptide produced by Lactococcus lactis. Nisin is also the only bacteriocin approved for use in food preservation. In this work, we analyzed the effect of nisin on the growth of Acanthamoeba castellanii trophozoites. METHODS: A total of 8 × 104 trophozoites were exposed to increasing concentrations of nisin to determine its activity. Changes in cell membrane and cellular cycle of trophozoites were investigated by flow cytometry, and nisin cytotoxicity in mammalian cells was evaluated in L929 cells by MTT method. RESULTS: After 24 h exposure to increasing nisin concentrations, an IC50 of 4493.2 IU mL-1 was obtained for A. castellanii trophozoites. However, after 72 h a recovery in amoebic growth was observed, and it was no longer possible to determine IC50. Flow cytometry analysis showed that nisin has no effect on the membrane integrity. Treatment with nisin induced cell-cycle arrest during G1 and S phases in A. castellanii trophozoites, which recovered their growth after 72 h. CONCLUSION: This is one of the first studies showing the effect of internationally approved nisin against A. castellanii trophozoites. Nisin caused cell-cycle arrest in trophozoites, momentarily interfering with the DNA replication process. The data highlight the amoebostatic activity of nisin, and suggest its use as an adjuvant for the treatment of infections caused by Acanthamoeba spp.
PURPOSE: Acanthamoeba spp. are free-living amoebas with worldwide distribution and play an important role as disease-causing agents in humans. Drug inability to completely eradicate these parasites along with their toxic effects suggest urgent need for new antimicrobials. Nisin is a natural antimicrobial peptide produced by Lactococcus lactis. Nisin is also the only bacteriocin approved for use in food preservation. In this work, we analyzed the effect of nisin on the growth of Acanthamoeba castellanii trophozoites. METHODS: A total of 8 × 104 trophozoites were exposed to increasing concentrations of nisin to determine its activity. Changes in cell membrane and cellular cycle of trophozoites were investigated by flow cytometry, and nisin cytotoxicity in mammalian cells was evaluated in L929 cells by MTT method. RESULTS: After 24 h exposure to increasing nisin concentrations, an IC50 of 4493.2 IU mL-1 was obtained for A. castellanii trophozoites. However, after 72 h a recovery in amoebic growth was observed, and it was no longer possible to determine IC50. Flow cytometry analysis showed that nisin has no effect on the membrane integrity. Treatment with nisin induced cell-cycle arrest during G1 and S phases in A. castellanii trophozoites, which recovered their growth after 72 h. CONCLUSION: This is one of the first studies showing the effect of internationally approved nisin against A. castellanii trophozoites. Nisin caused cell-cycle arrest in trophozoites, momentarily interfering with the DNA replication process. The data highlight the amoebostatic activity of nisin, and suggest its use as an adjuvant for the treatment of infections caused by Acanthamoeba spp.
Authors: Michael L Chikindas; Richard Weeks; Djamel Drider; Vladimir A Chistyakov; Leon Mt Dicks Journal: Curr Opin Biotechnol Date: 2017-08-05 Impact factor: 9.740