title: Thionin-like peptides from Capsicum annuum fruits with high activity against human pathogenic bacteria and yeasts.
abstract: Plants defend themselves against pathogens with production of antimicrobial peptides (AMPs). Herein we describe the discovery of a new antifungal and antibacterial peptide from fruits of Capsicum annuum that showed similarity to an already well characterized family of plant AMPs, thionins. Other fraction composed of two peptides, in which the major peptide also showed similarity to thionins. Among the obtained fractions, fraction 1, which is composed of a single peptide of 7 kDa, was sequenced by Edman method and its comparative sequence analysis in database (nr) showed similarity to thionin-like peptides. Tests against microorganisms, fraction 1 presented inhibitory activity to the cells of yeast Saccharomyces cerevisiae, Candida albicans, and Candida tropicalis and caused growth reduction to the bacteria species Escherichia coli and Pseudomonas aeruginosa. Fraction 3 caused inhibitory activity only for C. albicans and C. tropicalis. This fraction was composed of two peptides of ∼7 and 10 kDa, and the main protein band correspondent to the 7 kDa peptide, also showed similarity to thionins. This plasma membrane permeabilization assay demonstrates that the peptides present in the fractions 1 and 3 induced changes in the membranes of all yeast strains, leading to their permeabilization. Fraction 1 was capable of inhibiting acidification of the medium of glucose-induced S. cerevisiae cells 78% after an incubation time of 30 min, and opposite result was obtained for C. albicans. Experiments demonstrate that the fraction 1 and 3 were toxic and induced changes in the membranes of all yeast strains, leading to their permeabilization.
authors.affiliation: Center equivalent to department, Universidade Estadual do Norte Fluminense, Centro de Biociências e Biotecnologia, Campos dos Goytacazes, RJ, Brazil.
authors.forename: Gabriel B
authors.initials: GB
authors.lastname: Taveira
authors.forename: Luciana S
authors.initials: LS
authors.lastname: Mathias
authors.forename: Olney V
authors.initials: OV
authors.lastname: da Motta
authors.forename: Olga L T
authors.initials: OL
authors.lastname: Machado
authors.forename: Rosana
authors.initials: R
authors.lastname: Rodrigues
authors.forename: André O
authors.initials: AO
authors.lastname: Carvalho
authors.forename: André
authors.initials: A
authors.lastname: Teixeira-Ferreira
authors.forename: Jonas
authors.initials: J
authors.lastname: Perales
authors.forename: Ilka M
authors.initials: IM
authors.lastname: Vasconcelos
authors.forename: Valdirene M
authors.initials: VM
authors.lastname: Gomes
mesh_terms: D000143:Acids / Q000378:metabolism; D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D000935:Antifungal Agents / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects*; D002212:Capsicum / Q000737:chemistry*; D002463:Cell Membrane Permeability / Q000187:drug effects; D005591:Chemical Fractionation; D056148:Chromatography, Reverse-Phase; D004591:Electrophoresis, Polyacrylamide Gel; D005638:Fruit / Q000737:chemistry*; D005947:Glucose / Q000494:pharmacology; D006801:Humans; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D020539:Sequence Analysis, Protein; D054809:Thionins / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D015003:Yeasts / Q000187:drug effects*
chemical_list: D000143:Acids; D000900:Anti-Bacterial Agents; D000935:Antifungal Agents; D054809:Thionins; D005947:Glucose
keywords: Capsicum annuum; antimicrobial peptides; pathogenic microorganisms; thionins