A defensin with highly potent antipathogenic activities from the seeds of purple pole bean

2009 ◽  
Vol 30 (2) ◽  
pp. 101-109 ◽  
Author(s):  
Peng Lin ◽  
Jack Ho Wong ◽  
Tzi Bun Ng
Keyword(s):  
Gel Filtration ◽  
Antifungal Drugs ◽  
Fungal Resistance ◽  
Plant Defensin ◽  
Sytox Green ◽  
Plant Defensins ◽  
Congo Red Staining ◽  
Chromatographic Media ◽  
Erythrocyte Membrane Permeability ◽  
Hepatoma Hepg2

A 5443 Da peptide with sequence homology to defensins was purified from purple pole beans (Phaseolus vulgaris cv. ‘Extra-long Purple Pole bean’). This peptide was isolated by adsorption on an affinity chromatographic medium Affi-Gel Blue gel and ion-exchange chromatographic media SP-Sepharose (sulfopropyl-Sepharose) and Mono S and by gel filtration on Superdex peptide. The peptide inhibited mycelial growth in Mycosphaerella arachidicola, Helminthosporium maydis, Fusarium oxysporum, Verticillium dahliae, Rhizoctonia solani, Candida albicans and Setosphaeria turcica with an IC50 of 0.8, 0.9, 2.3, 3.2, 4.3, 4.8 and 9.8 μM respectively. Its antifungal potency was higher than that of the plant defensin coccinin (IC50>50 μM). It induced membrane permeabilization in C. albicans as evidenced by SYTOX Green uptake, but did not affect erythrocyte membrane permeability. It inhibited growth in M. arachidicola by inducing chitin accumulation at hyphal tips as was shown by Congo Red staining. The antifungal activity was pH stable and thermostable. The peptide inhibited the proliferation of hepatoma (HepG2), breast cancer (MCF7), colon cancer (HT29) and cervical cancer (SiHa) cells but not that of human embryonic liver (WRL68) cells. Its anti-HepG2 activity (IC50=4.1±0.8 μM, n=3) was higher than that of another plant defensin, gymnin (IC50>50 μM). Its anti-MCF7 activity (IC50=8.3±0.3 μM, n=3) was similar to that of other plant defensins. It reduced the activity of HIV-1 reverse transcriptase with an IC50 of 0.5±0.1 μM, n=3, much more potently than other plant defensins (IC50>40 μM). There is the possibility of using the purple pole bean defensin for producing antifungal drugs and/or transgenic plants with fungal resistance.

Permeabilization of Fungal Membranes by Plant Defensins Inhibits Fungal Growth

1999 ◽  
Vol 65 (12) ◽  
pp. 5451-5458 ◽  
Author(s):  
Karin Thevissen ◽  
Franky R. G. Terras ◽  
Willem F. Broekaert
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Antifungal Activity ◽  
Raphanus Sativus ◽  
Plasma Membranes ◽  
Fungal Growth ◽  
Membrane Permeabilization ◽  
Plant Defensin ◽  
Sytox Green ◽  
Plant Defensins ◽  
Fungal Growth Inhibition

ABSTRACT We used an assay based on the uptake of SYTOX Green, an organic compound that fluoresces upon interaction with nucleic acids and penetrates cells with compromised plasma membranes, to investigate membrane permeabilization in fungi. Membrane permeabilization induced by plant defensins in Neurospora crassa was biphasic, depending on the plant defensin dose. At high defensin levels (10 to 40 μM), strong permeabilization was detected that could be strongly suppressed by cations in the medium. This permeabilization appears to rely on direct peptide-phospholipid interactions. At lower defensin levels (0.1 to 1 μM), a weaker, but more cation-resistant, permeabilization occurred at concentrations that correlated with the inhibition of fungal growth. Rs-AFP2(Y38G), an inactive variant of the plant defensin Rs-AFP2 from Raphanus sativus, failed to induce cation-resistant permeabilization in N. crassa. Dm-AMP1, a plant defensin from Dahlia merckii, induced cation-resistant membrane permeabilization in yeast (Saccharomyces cerevisiae) which correlated with its antifungal activity. However, Dm-AMP1 could not induce cation-resistant permeabilization in the Dm-AMP1-resistantS. cerevisiae mutant DM1, which has a drastically reduced capacity for binding Dm-AMP1. We think that cation-resistant permeabilization is binding site mediated and linked to the primary cause of fungal growth inhibition induced by plant defensins.

Essential oils as alternative promising anti-Candidal agents: progress and prospects

2021 ◽  
Vol 27 ◽  
Author(s):  
Awad Shala ◽  
Shweta Singh ◽  
Saif Hameed ◽  
.M.P. Khurana
Keyword(s):  
Essential Oils ◽  
Antioxidant Properties ◽  
Therapeutic Agents ◽  
Antifungal Drugs ◽  
Fungal Resistance ◽  
Antifungal Compounds ◽  
Candida Spp ◽  
Conventional Antibiotics ◽  
Opportunistic Pathogenic

: Candida albicans is one of the main agents responsible for opportunistic pathogenic infections. The progressive emergence of fungal resistance to conventional antibiotics and its side effects as well as treatment costs are considered as major limitations for antifungal drugs. It has drawn scientists' attention to search for potential substitution and therapeutic reliable alternatives for the antifungal compounds from sources like medicinal plants, which contain numerous bioactive compounds such as essential oils. Essential oils (EO) apart from having lower toxicity and better biodegradability are eco-friendly in nature as compared with conventional antibiotics. Furthermore, extracted essential oils have been reported to possess potent antimicrobial, anti-inflammatory and antioxidant properties that nominate them as natural promising candidates to combat numerous fungal ailments. Thus, determination of antifungal efficacy of essential oil-bearing plants on Candida spp. will provide miscellaneous knowledge for future clinical studies that are required for development of new formulations as alternative therapeutic agents to control the growth of Candida species. Therefore, this review summarizes the gist of major essential oils that have been investigated for their anti- Candida potential with some recommendations for further study.

scholarly journals Plant defensin antibacterial mode of action against Pseudomonas species

2020 ◽  
Author(s):  
Andrew Edward Sathoff ◽  
Shawn Lewenza ◽  
Deborah A. Samac
Keyword(s):  
Gene Expression ◽  
Antibacterial Activity ◽  
Outer Membrane ◽  
Pseudomonas Syringae ◽  
Mode Of Action ◽  
Fluorescent Microscopy ◽  
Insertion Site ◽  
Membrane Damage ◽  
Plant Defensin ◽  
Plant Defensins

Abstract Background: Though many plant defensins exhibit antibacterial activity, little is known about their antibacterial mode of action (MOA). Antimicrobial peptides with a characterized MOA induce the expression of multiple bacterial outer membrane modifications, which are required for resistance to these membrane-targeting peptides. Mini-Tn5-lux mutant strains of Pseudomonas aeruginosa with Tn insertions disrupting outer membrane protective modifications were assessed for sensitivity against plant defensin peptides. These transcriptional lux reporter strains were also evaluated for lux gene expression in response to sublethal plant defensin exposure. Also, a plant pathogen, Pseudomonas syringae pv. syringae was modified through transposon mutagenesis to create mutants that are resistant to in vitro MtDef4 treatments.Results: Plant defensins displayed specific and potent antibacterial activity against strains of P. aeruginosa. A defensin from Medicago truncatula, MtDef4, induced dose-dependent gene expression of the aminoarabinose modification of LPS and surface polycation spermidine production operons. The ability for MtDef4 to damage bacterial outer membranes was also verified visually through fluorescent microscopy. Another defensin from M. truncatula, MtDef5, failed to induce lux gene expression and limited outer membrane damage was detected with fluorescent microscopy. The transposon insertion site on MtDef4 resistant P. syringae pv. syringae mutants was sequenced, and modifications of ribosomal genes were identified to contribute to enhanced resistance to plant defensin treatments. Conclusions: MtDef4 damages the outer membrane similar to polymyxin B, which stimulates antimicrobial peptide resistance mechanisms to plant defensins. MtDef5, appears to have a different antibacterial MOA. Additionally, the MtDef4 antibacterial mode of action may also involve inhibition of translation.

scholarly journals Plant Defensin Peptides have Antifungal and Antibacterial Activity Against Human and Plant Pathogens

2019 ◽  
Vol 109 (3) ◽  
pp. 402-408 ◽  
Author(s):  
Andrew E. Sathoff ◽  
Siva Velivelli ◽  
Dilip M. Shah ◽  
Deborah A. Samac
Keyword(s):  
Antibacterial Activity ◽  
Plant Pathogens ◽  
Crown Rot ◽  
Plant Defensin ◽  
Core Motif ◽  
Potential Control ◽  
Fungal Plant Pathogens ◽  
Plant Defensins ◽  
Animal Pathogens

Plant defensins are small, cysteine-rich antimicrobial peptides. These peptides have previously been shown to primarily inhibit the growth of fungal plant pathogens. Plant defensins have a γ-core motif, defined as GXCX3-9C, which is required for their antifungal activity. To evaluate plant defensins as a potential control for a problematic agricultural disease (alfalfa crown rot), short, chemically synthesized peptides containing γ-core motif sequences were screened for activity against numerous crown rot pathogens. These peptides showed both antifungal and, surprisingly, antibacterial activity. Core motif peptides from Medicago truncatula defensins (MtDef4 and MtDef5) displayed high activity against both plant and human bacterial pathogens in vitro. Full-length defensins had higher antimicrobial activity compared with the peptides containing their predictive γ-core motifs. These results show the future promise for controlling a wide array of economically important fungal and bacterial plant pathogens through the transgenic expression of a plant defensin. They also suggest that plant defensins may be an untapped reservoir for development of therapeutic compounds for combating human and animal pathogens.

scholarly journals Acylhydrazones as Antifungal Agents Targeting the Synthesis of Fungal Sphingolipids

2018 ◽  
Vol 62 (5) ◽  
Author(s):  
Cristina Lazzarini ◽  
Krupanandan Haranahalli ◽  
Robert Rieger ◽  
Hari Krishna Ananthula ◽  
Pankaj B. Desai ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Antifungal Agents ◽  
Fungal Infections ◽  
Antifungal Drugs ◽  
Fungal Resistance ◽  
Content Type ◽  
Highly Active ◽  
Pharmacokinetic Properties ◽  
Pass Through

ABSTRACTThe incidence of invasive fungal infections has risen dramatically in recent decades. Current antifungal drugs are either toxic, likely to interact with other drugs, have a narrow spectrum of activity, or induce fungal resistance. Hence, there is a great need for new antifungals, possibly with novel mechanisms of action. Previously our group reported an acylhydrazone called BHBM that targeted the sphingolipid pathway and showed strong antifungal activity against several fungi. In this study, we screened 19 derivatives of BHBM. Three out of 19 derivatives were highly active againstCryptococcus neoformansin vitroand had low toxicity in mammalian cells. In particular, one of them, called D13, had a high selectivity index and showed better activity in an animal model of cryptococcosis, candidiasis, and pulmonary aspergillosis. D13 also displayed suitable pharmacokinetic properties and was able to pass through the blood-brain barrier. These results suggest that acylhydrazones are promising molecules for the research and development of new antifungal agents.

scholarly journals Antifungal Resistance, Metabolic Routes as Drug Targets, and New Antifungal Agents: An Overview about Endemic Dimorphic Fungi

2017 ◽  
Vol 2017 ◽  
pp. 1-16 ◽  
Author(s):  
Juliana Alves Parente-Rocha ◽  
Alexandre Melo Bailão ◽  
André Correa Amaral ◽  
Carlos Pelleschi Taborda ◽  
Juliano Domiraci Paccez ◽  
...  
Keyword(s):  
Drug Targets ◽  
Antifungal Agents ◽  
Fungal Infections ◽  
Public Health Problem ◽  
Antifungal Drugs ◽  
Fungal Resistance ◽  
Immunocompromised Patients ◽  
Dimorphic Fungi ◽  
Novel Drug ◽  
Novel Drug Targets

Diseases caused by fungi can occur in healthy people, but immunocompromised patients are the major risk group for invasive fungal infections. Cases of fungal resistance and the difficulty of treatment make fungal infections a public health problem. This review explores mechanisms used by fungi to promote fungal resistance, such as the mutation or overexpression of drug targets, efflux and degradation systems, and pleiotropic drug responses. Alternative novel drug targets have been investigated; these include metabolic routes used by fungi during infection, such as trehalose and amino acid metabolism and mitochondrial proteins. An overview of new antifungal agents, including nanostructured antifungals, as well as of repositioning approaches is discussed. Studies focusing on the development of vaccines against antifungal diseases have increased in recent years, as these strategies can be applied in combination with antifungal therapy to prevent posttreatment sequelae. Studies focused on the development of a pan-fungal vaccine and antifungal drugs can improve the treatment of immunocompromised patients and reduce treatment costs.

Can plant defensins be used to engineer durable commercially useful fungal resistance in crop plants?

2011 ◽  
Vol 25 (3) ◽  
pp. 128-135 ◽  
Author(s):  
Jagdeep Kaur ◽  
Uma Shankar Sagaram ◽  
Dilip Shah
Keyword(s):  
Crop Plants ◽  
Fungal Resistance ◽  
Plant Defensins

scholarly journals Specific Binding Sites for an Antifungal Plant Defensin from Dahlia (Dahlia merckii) on Fungal Cells Are Required for Antifungal Activity

2000 ◽  
Vol 13 (1) ◽  
pp. 54-61 ◽  
Author(s):  
Karin Thevissen ◽  
Rupert W. Osborn ◽  
David P. Acland ◽  
Willem F. Broekaert
Keyword(s):  
Antifungal Activity ◽  
Plasma Membranes ◽  
Specific Binding ◽  
Plant Defensin ◽  
Wild Type ◽  
Whole Cells ◽  
Specific Binding Sites ◽  
Plant Defensins ◽  
Related Plant ◽  
Wild Type Yeast

Dm-AMP1, an antifungal plant defensin from seeds of dahlia (Dahlia merckii), was radioactively labeled with t-butoxycarbonyl-[35S]-L-methionine N-hydroxy-succinimi-dylester. This procedure yielded a 35S-labeled peptide with unaltered antifungal activity. [35S]Dm-AMP1 was used to assess binding on living cells of the filamentous fungus Neurospora crassa and the unicellular fungus Saccharomyces cerevisiae. Binding of [35S]Dm-AMP1 to fungal cells was saturable and could be competed for by preincubation with excess, unlabeled Dm-AMP1 as well as with Ah-AMP1 and Ct-AMP1, two plant defensins that are highly homologous to Dm-AMP1. In contrast, binding could not be competed for by more distantly related plant defensins or structurally unrelated antimicrobial peptides. Binding of [35S]Dm-AMP1 to either N. crassa or S. cerevisiae cells was apparently irreversible. In addition, whole cells and microsomal membrane fractions from two independently obtained S. cerevisiae mutants selected for resistance to Dm-AMP1 exhibited severely reduced binding affinity for [35S]Dm-AMP1, compared with wild-type yeast. This finding suggests that binding of Dm-AMP1 to S. cerevisiae plasma membranes is required for antifungal activity of this protein.

scholarly journals Fungicide effects on human fungal pathogens: Cross-resistance to medical drugs and beyond

2021 ◽  
Vol 17 (12) ◽  
pp. e1010073
Author(s):  
Rafael W. Bastos ◽  
Luana Rossato ◽  
Gustavo H. Goldman ◽  
Daniel A. Santos
Keyword(s):  
Fungal Pathogens ◽  
Fungal Infections ◽  
Resistance Mechanism ◽  
Antifungal Resistance ◽  
Antifungal Drugs ◽  
Fungal Resistance ◽  
Cross Resistance ◽  
Term Therapy ◽  
Prior History ◽  
Plant Materials

Fungal infections are underestimated threats that affect over 1 billion people, and Candida spp., Cryptococcus spp., and Aspergillus spp. are the 3 most fatal fungi. The treatment of these infections is performed with a limited arsenal of antifungal drugs, and the class of the azoles is the most used. Although these drugs present low toxicity for the host, there is an emergence of therapeutic failure due to azole resistance. Drug resistance normally develops in patients undergoing azole long-term therapy, when the fungus in contact with the drug can adapt and survive. Conversely, several reports have been showing that resistant isolates are also recovered from patients with no prior history of azole therapy, suggesting that other routes might be driving antifungal resistance. Intriguingly, antifungal resistance also happens in the environment since resistant strains have been isolated from plant materials, soil, decomposing matter, and compost, where important human fungal pathogens live. As the resistant fungi can be isolated from the environment, in places where agrochemicals are extensively used in agriculture and wood industry, the hypothesis that fungicides could be driving and selecting resistance mechanism in nature, before the contact of the fungus with the host, has gained more attention. The effects of fungicide exposure on fungal resistance have been extensively studied in Aspergillus fumigatus and less investigated in other human fungal pathogens. Here, we discuss not only classic and recent studies showing that environmental azole exposure selects cross-resistance to medical azoles in A. fumigatus, but also how this phenomenon affects Candida and Cryptococcus, other 2 important human fungal pathogens found in the environment. We also examine data showing that fungicide exposure can select relevant changes in the morphophysiology and virulence of those pathogens, suggesting that its effect goes beyond the cross-resistance.

scholarly journals Antifungal Drug Repurposing

Antibiotics ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 812
Author(s):  
Jong H. Kim ◽  
Luisa W. Cheng ◽  
Kathleen L. Chan ◽  
Christina C. Tam ◽  
Noreen Mahoney ◽  
...  
Keyword(s):  
Fungal Pathogens ◽  
Gene Promoter ◽  
Drug Repurposing ◽  
Antifungal Drugs ◽  
Fungal Resistance ◽  
Alternative Methods ◽  
Effective Control ◽  
Environmental Selection ◽  
Antifungal Action ◽  
Azole Fungicides

Control of fungal pathogens is increasingly problematic due to the limited number of effective drugs available for antifungal therapy. Conventional antifungal drugs could also trigger human cytotoxicity associated with the kidneys and liver, including the generation of reactive oxygen species. Moreover, increased incidences of fungal resistance to the classes of azoles, such as fluconazole, itraconazole, voriconazole, or posaconazole, or echinocandins, including caspofungin, anidulafungin, or micafungin, have been documented. Of note, certain azole fungicides such as propiconazole or tebuconazole that are applied to agricultural fields have the same mechanism of antifungal action as clinical azole drugs. Such long-term application of azole fungicides to crop fields provides environmental selection pressure for the emergence of pan-azole-resistant fungal strains such as Aspergillus fumigatus having TR34/L98H mutations, specifically, a 34 bp insertion into the cytochrome P450 51A (CYP51A) gene promoter region and a leucine-to-histidine substitution at codon 98 of CYP51A. Altogether, the emerging resistance of pathogens to currently available antifungal drugs and insufficiency in the discovery of new therapeutics engender the urgent need for the development of new antifungals and/or alternative therapies for effective control of fungal pathogens. We discuss the current needs for the discovery of new clinical antifungal drugs and the recent drug repurposing endeavors as alternative methods for fungal pathogen control.

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