Antibacterial Activity of Defensin PaDef from Avocado Fruit (Persea americanavar.drymifolia) Expressed in Endothelial Cells againstEscherichia coliandStaphylococcus aureus

Abstract

Antimicrobial therapy is a useful tool to control infectious diseases in general and rising antibiotic resistant microorganisms in particular. Alternative strategies are desirable, and antimicrobial peptides (AMP) represent attractive control agents. Mexican avocado (Persea americana var. drymifolia) is used in traditional medicine; however, the AMP production has not been reported in this plant. We obtained a cDNA library from avocado fruit and clone PaDef was identified, which has a cDNA (249 bp) encoding a protein (78 aa) homologous with plant defensins (>80%). We expressed the defensin PaDef cDNA (pBME3) in the bovine endothelial cell line BVE-E6E7. Polyclonal and clonal populations were obtained and their activity was evaluated against Escherichia coli, Staphylococcus aureus, and Candida albicans. E. coli viability was inhibited with 100 μg/mL of total protein from clones (>55%). Also, S. aureus viability was inhibited from 50 μg/mL total protein (27–38%) but was more evident at 100 μg/mL (52–65%). This inhibition was higher than the effect showed by polyclonal population (~23%). Finally, we did not detect activity against C. albicans. These results are the first report that shows antimicrobial activity of a defensin produced by avocado and suggest that this AMP could be used in the control of pathogens.

Antimicrobial Peptides from Fruits and Their Potential Use as Biotechnological Tools—A Review and Outlook

“…Additionally to this classification, several classes of plant AMPs can also be divided by properties, such as covalent bonding patterns, hydrophobicity, net charge, or molecular targets (Wang, 2015). Among several different plant AMP classes, in fruits it is possible to detect (I) defensins (Meyer et al, 1996; Guzmán-Rodríguez et al, 2013; Seo et al, 2014), (II) lipid transfer proteins (LTPs) (Zottich et al, 2011), (III) glycine rich protein (Pelegrini et al, 2008), (IV) 2S albumin (Pelegrini et al, 2006; Ribeiro et al, 2011), (V) snakin (Daneshmand et al, 2013), (VI) napin (Da Silva Dantas et al, 2014), and (VII) and other fruit AMPs (Table 1). …”

“…), showed antibacterial activity against Gram-positive and negative bacteria. Pa Def should inhibit 67.43 and 78.08% of the viability of Escherichia coli and Staphylococcus aureus , respectively, in concentrations for 10 at 100 μg.mL −1 , but it did not show deleterious activity against Candida albicans (Guzmán-Rodríguez et al, 2013). The tomato defensin TPP3 has a lipid binding specific for phosphatidylinositol (4,5)-bisphosphate (PIP2) with which it forms a dimeric configuration complex that is critical for membrane permeabilization and inhibits hyphal growth of Fusarium graminearum (Baxter et al, 2015).…”

“…It has been proposed that plant AMPs, based on their broad-spectrum activity and efficiency, may offer a good alternative for the treatment of infections in relation to conventional antibiotics (da Silva and Machado, 2012). Some studies have shown the presence of different AMPs in fruits of Capsicum (Liu et al, 2006; Taveira et al, 2014) and avocado fruit ( Pa Def), presenting antimicrobial activities that could be used in the treatment of infectious diseases caused by E. coli and S. aureus strains (Guzmán-Rodríguez et al, 2013). Moreover, the peptide Ca Thi associated with fluconazole showed inhibitory activities toward C. albicans, C. tropicalis, C. parapsilosis, C. pelliculosa, C. buinensis , and C. mogii (Taveira et al, 2016).…”

The defensin from avocado (Persea americana var. drymifolia) PaDef induces apoptosis in the human breast cancer cell line MCF-7

“…PaDef used in this work corresponds to the mature region (ATCETPSKHFNGLCIRSSNCASVCHGEHFTDGRCQGVRRRCMCLKPC, 47 aa) (Genbank KC007441) [18], which was chemically synthesized and obtained from BIOMATIK. Prior to assays, PaDef (5 mg/ ml) disulfide bond formation was accomplished by air oxidation in dimethyl sulfoxide (20%) for 5 days at room temperature.…”

“…drymifolia) and expressed it as a fusion protein in the endothelial cell line BVE-E6E7. We showed that the conditioned media from these cells have antimicrobial activity against Escherichia coli and Staphylococcus aureus, important pathogens affecting animals and humans [18]. However, its cytotoxic effect has not been explored.…”