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.

Antimicrobial activity and mechanism of action of a thionin‐like peptide from Capsicum annuum fruits and combinatorial treatment with fluconazole against Fusarium solani

“…Ca Thi extraction and purification were accomplished as described by Taveira et al Briefly, eighty grams of C. annuum fruits (without seeds) were extracted for 2 h (at 4°C) with 400 mL of extraction buffer (10 m M Na 2 HPO 4 , 15 m M NaH 2 PO 4 , 100 m M KCl, 1.5% EDTA, pH 5.4; Sigma). Extracted proteins were precipitated with 0 and 70% relative ammonium sulfate (472 g L −1 ; Merck) saturation and centrifuged at 20,000 g for 30 min at 4°C.…”

“…In previous reports, our group isolated a thionin‐like peptide, named Ca Thi, from Capsicum annuum fruits. This peptide had strong antimicrobial activity against Escherichia coli and Staphylococcus aureus as well as candidacidal activity against six Candida species.…”

ANTIMICROBIAL PEPTIDES IN SEMEN EXTENDERS: A VALUABLE REPLACEMENT OPTION FOR ANTIBIOTICS IN CRYOPRESERVATION- A Prospective Review

“…The N-terminal sequence of these peptides was shown with highest similarity level with serine protease inhibitors (SPI) when analyzed through proper database systems. Taveira et al identified a protein that is equal to the compound thionin from capsicum that has severe antifungal and antibacterial activity, and this shows effective therapeutic reactions against Candida species (Taveira et al, 2014;Taveira et al, 2016). In this research, the author concluded that antimicrobial peptides isolated and purified from capsicum demonstrated in vitro inhibitory activity against a range of fungi and sometimes with bacteria of agronomic importance.…”

Purification, biochemical characterization, and antimicrobial activity of a new lipid transfer protein from Coffea canephora seeds

“…Besides LTPs, other AMPs are able to increase membrane permeability in various microorganisms. Such AMPs include defensins such as PvD1 isolated from Phaseolus vulgaris (Mello et al, 2011), thionin (Taveira et al, 2014), and trypsin-chymotrypsin inhibitors (Ribeiro et al, 2012) isolated from C. annuum. It is important to note that membrane permeation and growth inhibition are not necessarily related.…”