title: Thionin-like peptide from Capsicum annuum fruits: mechanism of action and synergism with fluconazole against Candida species.
abstract: BACKGROUND
  Thionins are a family of plant antimicrobial peptides (AMPs), which participate in plant defense system against pathogens. Here we describe some aspects of the CaThi thionin-like action mechanism, previously isolated from Capsicum annuum fruits. Thionin-like peptide was submitted to antimicrobial activity assays against Candida species for IC50 determination and synergism with fluconazole evaluation. Viability and plasma membrane permeabilization assays, induction of intracellular ROS production analysis and CaThi localization in yeast cells were also investigated.
  
  
  RESULTS
  CaThi had strong antimicrobial activity against six tested pathogenic Candida species, with IC50 ranging from 10 to 40 μg.mL(-1). CaThi antimicrobial activity on Candida species was candidacidal. Moreover, CaThi caused plasma membrane permeabilization in all yeasts tested and induces oxidative stresses only in Candida tropicalis. CaThi was intracellularly localized in C. albicans and C. tropicalis, however localized in nuclei in C. tropicalis, suggesting a possible nuclear target. CaThi performed synergistically with fluconazole inhibiting all tested yeasts, reaching 100% inhibition in C. parapsilosis. The inhibiting concentrations for the synergic pair ranged from 1.3 to 4.0 times below CaThi IC50 and from zero to 2.0 times below fluconazole IC50.
  
  
  CONCLUSIONS
  The results reported herein may ultimately contribute to future efforts aiming to employ this plant-derived AMP as a new therapeutic substance against yeasts.
authors.affiliation: Laboratório de Fisiologia e Bioquímica de Microrganismos, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, 28013-602, , RJ, Brazil. gabrielbtaveira@yahoo.com.br.
authors.forename: Gabriel B
authors.initials: GB
authors.lastname: Taveira
authors.affiliation: Laboratório de Fisiologia e Bioquímica de Microrganismos, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, 28013-602, , RJ, Brazil. andre@uenf.br.
authors.forename: André O
authors.initials: AO
authors.lastname: Carvalho
authors.affiliation: Laboratório de Melhoramento Genético Vegetal, Centro de Ciências e Tecnologias Agropecuárias, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, 28013-602, , RJ, Brazil. rosana@uenf.br.
authors.forename: Rosana
authors.initials: R
authors.lastname: Rodrigues
authors.affiliation: Laboratório de Biologia Celular e Tecidual, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, 28013-602, , RJ, Brazil. nanda_trindad@hotmail.com.
authors.forename: Fernanda G
authors.initials: FG
authors.lastname: Trindade
authors.affiliation: Laboratório de Biologia Celular e Tecidual, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, 28013-602, , RJ, Brazil. maurauenf@gmail.com.
authors.forename: Maura
authors.initials: M
authors.lastname: Da Cunha
authors.affiliation: Laboratório de Fisiologia e Bioquímica de Microrganismos, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, 28013-602, , RJ, Brazil. valmg@uenf.br.
authors.forename: Valdirene M
authors.initials: VM
authors.lastname: Gomes
mesh_terms: D000935:Antifungal Agents / Q000494:pharmacology*; D002175:Candida / Q000187:drug effects* / Q000254:growth & development; D002212:Capsicum / Q000737:chemistry*; D004357:Drug Synergism; D015725:Fluconazole / Q000494:pharmacology*; D005638:Fruit / Q000737:chemistry; D008826:Microbial Sensitivity Tests; D054809:Thionins / Q000494:pharmacology*
chemical_list: D000935:Antifungal Agents; D054809:Thionins; D015725:Fluconazole
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