Interaction between the plant ApDef1 defensin and Saccharomyces cerevisiae results in yeast death through a cell cycle- and caspase-dependent process occurring via uncontrolled oxidative stress

Potent in vitro and in vivo antifungal activity of a small molecule host defense peptide mimic through a membrane-active mechanism

“…Like C4, human defensins (HNPs), the plant defensin HsAFP-1 and other plant defensins exhibit an initial interaction with the fungal phospholipids or sphingolipids in the membrane that is inhibited by cations 13 , supporting our hypothesis that small molecule mimics of cationic HDPs target fungi through a membrane-directed pathway. However, similar to the plant defensin ApDef1 36 we also observe some intracellular effects, suggesting multiple targets of this compound. Polymyxin B, a pore-forming antibiotic which has been used as an bactericidal agent for many years, also exhibits intracellular activity 37 .…”

“…Further studies are necessary to determine whether C4-mediated cell death is due to apoptosis, autophagy or oncosis 42 . While our data indicates that cell death by C4 in C albicans is primarily initiated in an autophagy-like manner we cannot exclude the possibility the C4 also induced reactive oxygen species as seen in ApDef1 treated Saccharomyces cerevisiae , the non-pathogenic baker’s yeast 36 . Further investigation to determine the induction of autophagy genes and the induction of reactive oxygen species may lead to a clearer interpretation of how C4 acts once inside pathogenic yeast.…”

“…LL-37 has been observed to affect several cellular pathways as well 40 . The recently described mechanism by which a plant defensin, ApDef1, damages fungi with the induction of endogenous reactive oxygen species 36 is yet another example by which fungal cell death is mediated.…”

Physiological and Proteomic Changes in the Apoplast Accompany Leaf Senescence in Arabidopsis

“…Proteomic approaches identified chitinases, pathogenesis related proteins (PR), and other defense related enzymes, as the mayor leaf apoplastic proteins (Boudart et al, 2005;Rutter and Innes, 2017;Soares et al, 2017). The extracellular accumulation of these enzymes along with the transient alkalinization of pH apo as signature of different biotic and abiotic stress responses suggest either a cross-talk between stress pathways or a common apoplastic signal-transducing element or node (Geilfus, 2017).…”

Improved smallest peptides based on positive charge increase of the &gamma;-core motif from <em>P&nu;</em>D₁ and their mechanism of action against <em>Candida</em> species

“…7,11,12 Among the activities already described, the best characterized is their growth inhibition of a large variety of filamentous fungi and yeasts, including those pathogenic to humans. 3,7,[13][14][15][16][17] The mechanism of action involved in the fungal growth inhibition by plant defensins has been investigated by several authors, and the evidence demonstrates several steps involving an extracellular mechanism acting on the cell wall and/or plasma membrane, further acting on intracellular targets. 7,9,15,18 In addition to this whole membrane permeabilization process involving plant defensins, some defensins have been shown to induce apoptosis or programmed cell death in susceptible yeast and fungal species.…”