1
|
Holzknecht J, Marx F. Navigating the fungal battlefield: cysteine-rich antifungal proteins and peptides from Eurotiales. FRONTIERS IN FUNGAL BIOLOGY 2024; 5:1451455. [PMID: 39323611 PMCID: PMC11423270 DOI: 10.3389/ffunb.2024.1451455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2024] [Accepted: 08/12/2024] [Indexed: 09/27/2024]
Abstract
Fungi are ubiquitous in the environment and play a key role in the decomposition and recycling of nutrients. On the one hand, their special properties are a great asset for the agricultural and industrial sector, as they are used as source of nutrients, producers of enzymes, pigments, flavorings, and biocontrol agents, and in food processing, bio-remediation and plant growth promotion. On the other hand, they pose a serious challenge to our lives and the environment, as they are responsible for fungal infections in plants, animals and humans. Although host immunity opposes invading pathogens, certain factors favor the manifestation of fungal diseases. The prevalence of fungal infections is on the rise, and there is an alarming increase in the resistance of fungal pathogens to approved drugs. The limited number of antimycotics, the obstacles encountered in the development of new drugs due to the poor tolerability of antifungal agents in patients, the limited number of unique antifungal targets, and the low species specificity contribute to the gradual depletion of the antifungal pipeline and newly discovered antifungal drugs are rare. Promising candidates as next-generation therapeutics are antimicrobial proteins and peptides (AMPs) produced by numerous prokaryotic and eukaryotic organisms belonging to all kingdom classes. Importantly, filamentous fungi from the order Eurotiales have been shown to be a rich source of AMPs with specific antifungal activity. A growing number of published studies reflects the efforts made in the search for new antifungal proteins and peptides (AFPs), their efficacy, species specificity and applicability. In this review, we discuss important aspects related to fungi, their impact on our life and issues involved in treating fungal infections in plants, animals and humans. We specifically highlight the potential of AFPs from Eurotiales as promising alternative antifungal therapeutics. This article provides insight into the structural features, mode of action, and progress made toward their potential application in a clinical and agricultural setting. It also identifies the challenges that must be overcome in order to develop AFPs into therapeutics.
Collapse
Affiliation(s)
| | - Florentine Marx
- Biocenter, Institute of Molecular Biology, Innsbruck Medical University,
Innsbruck, Austria
| |
Collapse
|
2
|
Chen YP, Li Y, Chen F, Wu H, Zhang S. Characterization and expression of fungal defensin in Escherichia coli and its antifungal mechanism by RNA-seq analysis. Front Microbiol 2023; 14:1172257. [PMID: 37389349 PMCID: PMC10306309 DOI: 10.3389/fmicb.2023.1172257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 05/22/2023] [Indexed: 07/01/2023] Open
Abstract
Introduction Invasive fungal infections (IFIs) are fatally threatening to critical patients. The fungal defensin as an antifungal protein can widely inhibit fungi. Methods In this study, eight antifungal genes from different filamentous fungi were optimized by synonymous codon bias and heterologously expressed in Escherichia coli. Results and discussion Only the antifungal protein (AFP) from Aspergillus giganteus was produced, whereas the AFP from its mutation of the chitin-binding domain could not be expressed, thereby suggesting the importance of the motif for protein folding. In addition, the recombinant AFP (rAFP, 100 μg/mL) pre-heated at 50°C for 1 h effectively inhibited Paecilomyces variotii CICC40716 of IFIs by 55%, and no cell cytotoxicity was observed in RAW264.7 cells. After being pre-heated at 50°C for 8 h, the fluorescence emission intensity of the rAFP decreased and shifted from 343 nm to 335 nm. Moreover, the helix and β-turn of the rAFP gradually decreased with the pre-heated treatment temperature of 50°C via circular dichroism spectroscopy. Propidium iodide staining revealed that the rAFP could cause damage to the cell membrane. Moreover, the corresponding differentially expressed genes (DEGs) for downregulation such as amino sugar and nucleotide sugar metabolism, as well as mitogen-activated protein kinase (MAPK) signaling pathway involved in the cell wall integrity were found via the RNA-seq of rAFP treatment. By contrast, the upregulated DEGs were enriched in response to the oxidative stress of Biological Process by the Gene Ontology (GO) database. The encoding proteins of laccase, multicopper oxidase, and nitroreductase that contributed to reactive oxygen species (ROS) scavenging could be recognized. These results suggested that the rAFP may affect the integrity of the cell wall and cell membrane, and promote the increase in ROS, thereby resulting in fungal death. Consequently, drug development could be based on the inhibitory effect of the rAFP on IFIs.
Collapse
Affiliation(s)
- Yu-Pei Chen
- Department of Public Health and Medical Technology, Xiamen Medical College, Xiamen, Fujian, China
- Engineering Research Center of Natural Cosmeceuticals College of Fujian Province, Xiamen Medical College, Xiamen, Fujian, China
- School of Public Health, Fujian Medical University, Fuzhou, Fujian, China
| | - Yingying Li
- Engineering Research Center of Natural Cosmeceuticals College of Fujian Province, Xiamen Medical College, Xiamen, Fujian, China
- Department of Medical Technology, Xiamen Medical College, Xiamen, Fujian, China
| | - Fangfang Chen
- Department of Public Health and Medical Technology, Xiamen Medical College, Xiamen, Fujian, China
- Engineering Research Center of Natural Cosmeceuticals College of Fujian Province, Xiamen Medical College, Xiamen, Fujian, China
| | - Hongtan Wu
- Department of Public Health and Medical Technology, Xiamen Medical College, Xiamen, Fujian, China
- Engineering Research Center of Natural Cosmeceuticals College of Fujian Province, Xiamen Medical College, Xiamen, Fujian, China
| | - Shudi Zhang
- Department of Public Health and Medical Technology, Xiamen Medical College, Xiamen, Fujian, China
- Engineering Research Center of Natural Cosmeceuticals College of Fujian Province, Xiamen Medical College, Xiamen, Fujian, China
| |
Collapse
|
3
|
Fardella PA, Clarke BB, Belanger FC. The Epichloë festucae Antifungal Protein Efe-AfpA Has Activity against Numerous Plant Pathogens. Microorganisms 2023; 11:microorganisms11040828. [PMID: 37110250 PMCID: PMC10145699 DOI: 10.3390/microorganisms11040828] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 03/17/2023] [Accepted: 03/22/2023] [Indexed: 04/29/2023] Open
Abstract
Fungal plant pathogens can present major problems for most crop species. Currently, control of fungal diseases relies heavily on the use of fungicides. However, there are problems associated with fungicide use, including potential toxicity to non-target organisms and the development of resistance in the target fungus. New strategies are being sought to reduce fungicide use. One area of active research is the potential use of antifungal proteins from various fungal species as alternatives or complements to traditional fungicides. An antifungal protein, Efe-AfpA, from the fungal endophyte Epichloë festucae was previously found to protect plants from the pathogen Clarireedia jacksonii, the causal agent of dollar spot disease. Here we report that Efe-AfpA also has inhibitory activity against other important plant pathogens. These results suggest that it may be possible to develop Efe-AfpA as a biofungicide to target a broad range of destructive plant pathogens.
Collapse
Affiliation(s)
- Patrick A Fardella
- Department of Plant Biology, Rutgers University, New Brunswick, NJ 08901, USA
| | - Bruce B Clarke
- Department of Plant Biology, Rutgers University, New Brunswick, NJ 08901, USA
| | - Faith C Belanger
- Department of Plant Biology, Rutgers University, New Brunswick, NJ 08901, USA
| |
Collapse
|
4
|
Fardella PA, Tian Z, Clarke BB, Belanger FC. The Epichloë festucae Antifungal Protein Efe-AfpA Protects Creeping Bentgrass ( Agrostis stolonifera) from the Plant Pathogen Clarireedia jacksonii, the Causal Agent of Dollar Spot Disease. J Fungi (Basel) 2022; 8:jof8101097. [PMID: 36294663 PMCID: PMC9605492 DOI: 10.3390/jof8101097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 10/11/2022] [Accepted: 10/15/2022] [Indexed: 11/16/2022] Open
Abstract
Dollar spot disease, caused by the fungal pathogen Clarireedia jacksonii, is a major problem in many turfgrass species, particularly creeping bentgrass (Agrostis stolonifera). It is well-established that strong creeping red fescue (Festuca rubra subsp. rubra) exhibits good dollar spot resistance when infected by the fungal endophyte Epichloë festucae. This endophyte-mediated disease resistance is unique to the fine fescues and has not been observed in other grass species infected with other Epichloë spp. The mechanism underlying the unique endophyte-mediated disease resistance in strong creeping red fescue has not yet been established. We pursued the possibility that it may be due to the presence of an abundant secreted antifungal protein produced by E. festucae. Here, we compare the activity of the antifungal protein expressed in Escherichia coli, Pichia pastoris, and Penicillium chrysogenum. Active protein was recovered from all systems, with the best activity being from Pe. chrysogenum. In greenhouse assays, topical application of the purified antifungal protein to creeping bentgrass and endophyte-free strong creeping red fescue protected the plants from developing severe symptoms caused by C. jacksonii. These results support the hypothesis that Efe-AfpA is a major contributor to the dollar spot resistance observed with E. festucae-infected strong creeping red fescue in the field, and that this protein could be developed as an alternative or complement to fungicides for the management of this disease on turfgrasses.
Collapse
|
5
|
Snelders NC, Rovenich H, Thomma BPHJ. Microbiota manipulation through the secretion of effector proteins is fundamental to the wealth of lifestyles in the fungal kingdom. FEMS Microbiol Rev 2022; 46:fuac022. [PMID: 35604874 PMCID: PMC9438471 DOI: 10.1093/femsre/fuac022] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 05/19/2022] [Indexed: 11/13/2022] Open
Abstract
Fungi are well-known decomposers of organic matter that thrive in virtually any environment on Earth where they encounter wealths of other microbes. Some fungi evolved symbiotic lifestyles, including pathogens and mutualists, that have mostly been studied in binary interactions with their hosts. However, we now appreciate that such interactions are greatly influenced by the ecological context in which they take place. While establishing their symbioses, fungi not only interact with their hosts but also with the host-associated microbiota. Thus, they target the host and its associated microbiota as a single holobiont. Recent studies have shown that fungal pathogens manipulate the host microbiota by means of secreted effector proteins with selective antimicrobial activity to stimulate disease development. In this review, we discuss the ecological contexts in which such effector-mediated microbiota manipulation is relevant for the fungal lifestyle and argue that this is not only relevant for pathogens of plants and animals but also beneficial in virtually any niche where fungi occur. Moreover, we reason that effector-mediated microbiota manipulation likely evolved already in fungal ancestors that encountered microbial competition long before symbiosis with land plants and mammalian animals evolved. Thus, we claim that effector-mediated microbiota manipulation is fundamental to fungal biology.
Collapse
Affiliation(s)
- Nick C Snelders
- Institute for Plant Sciences, University of Cologne, D-50674 Cologne, Germany
- Theoretical Biology & Bioinformatics Group, Department of Biology, Utrecht University, 3584 CH Utrecht, The Netherlands
| | - Hanna Rovenich
- Institute for Plant Sciences, University of Cologne, D-50674 Cologne, Germany
| | - Bart P H J Thomma
- Institute for Plant Sciences, University of Cologne, D-50674 Cologne, Germany
- Cluster of Excellence on Plant Sciences, Institute for Plant Sciences, University of Cologne, D-50674 Cologne, Germany
| |
Collapse
|
6
|
Huber A, Galgóczy L, Váradi G, Holzknecht J, Kakar A, Malanovic N, Leber R, Koch J, Keller MA, Batta G, Tóth GK, Marx F. Two small, cysteine-rich and cationic antifungal proteins from Penicillium chrysogenum: A comparative study of PAF and PAFB. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2020; 1862:183246. [PMID: 32142818 PMCID: PMC7138148 DOI: 10.1016/j.bbamem.2020.183246] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 02/06/2020] [Accepted: 02/10/2020] [Indexed: 12/16/2022]
Abstract
The filamentous fungus Penicillium chrysogenum Q176 secretes the antimicrobial proteins (AMPs) PAF and PAFB, which share a compact disulfide-bond mediated, β-fold structure rendering them highly stable. These two AMPs effectively inhibit the growth of human pathogenic fungi in micromolar concentrations and exhibit antiviral potential without causing cytotoxic effects on mammalian cells in vitro and in vivo. The antifungal mechanism of action of both AMPs is closely linked to - but not solely dependent on - the lipid composition of the fungal cell membrane and requires a strictly regulated protein uptake into the cell, indicating that PAF and PAFB are not canonical membrane active proteins. Variations in their antifungal spectrum and their killing dynamics point towards a divergent mode of action related to their physicochemical properties and surface charge distribution. In this review, we relate characteristic features of PAF and PAFB to the current knowledge about other AMPs of different sources. In addition, we present original data that have never been published before to substantiate our assumptions and provide evidences that help to explain and understand better the mechanistic function of PAF and PAFB. Finally, we underline the promising potential of PAF and PAFB as future antifungal therapeutics.
Collapse
Affiliation(s)
- A Huber
- Institute of Molecular Biology, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - L Galgóczy
- Institute of Plant Biology, Biological Research Centre, 6726 Szeged, Hungary; Department of Biotechnology, Faculty of Science and Informatics, University of Szeged, 6726 Szeged, Hungary
| | - G Váradi
- Department of Medical Chemistry, Faculty of Medicine, University of Szeged, 6720 Szeged, Hungary
| | - J Holzknecht
- Institute of Molecular Biology, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - A Kakar
- Institute of Molecular Biology, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - N Malanovic
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, Graz, Austria
| | - R Leber
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, Graz, Austria
| | - J Koch
- Institute of Human Genetics, Medical University of Innsbruck, Austria
| | - M A Keller
- Institute of Human Genetics, Medical University of Innsbruck, Austria
| | - G Batta
- Department of Organic Chemistry, Faculty of Science and Technology, University of Debrecen, 4032 Debrecen, Hungary
| | - G K Tóth
- Department of Medical Chemistry, Faculty of Medicine, University of Szeged, 6720 Szeged, Hungary; MTA-SZTE Biomimetic Systems Research Group, University of Szeged, 6720 Szeged, Hungary
| | - F Marx
- Institute of Molecular Biology, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria.
| |
Collapse
|
7
|
Tong S, Li M, Keyhani NO, Liu Y, Yuan M, Lin D, Jin D, Li X, Pei Y, Fan Y. Characterization of a fungal competition factor: Production of a conidial cell-wall associated antifungal peptide. PLoS Pathog 2020; 16:e1008518. [PMID: 32324832 PMCID: PMC7200012 DOI: 10.1371/journal.ppat.1008518] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 05/05/2020] [Accepted: 04/05/2020] [Indexed: 01/16/2023] Open
Abstract
Competition is one of the fundamental driving forces of natural selection. Beauveria bassiana is a soil and plant phylloplane/root fungus capable of parasitizing insect hosts. Soil and plant environments are often enriched with other fungi against which B. bassiana competes for survival. Here, we report an antifungal peptide (BbAFP1), specifically expressed and localized to the conidial cell wall and is released into the surrounding microenvironment inhibiting growth of competing fungi. B. bassiana strains expressing BbAFP1, including overexpression strains, inhibited growth of Alternaria brassicae in co-cultured experiments, whereas targeted gene deletion of BbAFP1 significantly decreased (25%) this inhibitory effect. Recombinant BbAFP1 showed chitin and glucan binding abilities, and growth inhibition of a wide range of phytopathogenic fungi by disrupting membrane integrity and eliciting reactive oxygen species (ROS) production. A phenylalanine residue (F50) contributes to chitin binding and antifungal activity, but was not required for the latter. Expression of BbAFP1 in tomato resulted in transgenic plants with enhanced resistance to plant fungal pathogens. These results highlight the importance of fungal competition in shaping primitive competition strategies, with antimicrobial compounds that can be embedded in the spore cell wall to be released into the environment during the critical initial phases of germination for successful growth in its environmental niche. Furthermore, these peptides can be exploited to increase plant resistance to fungal pathogens. Microbial competition exerts powerful selective pressures for the development of defensive and offensive methods of suppressing potential competitors. One of the most vulnerable stages for any fungi is the initial germination of resting spores in potentially hostile environments. Currently, we know little about how fungi defend other microbial competitors during the beginning stage of conidial germination. Here, we report on an antifungal peptide from B. bassiana (BbAFP1) that is specifically expressed in mature aerial conidia, with the protein localized exclusively to the conidial cell wall. The “pre-loaded” BbAFP1 is released into the surrounding microenvironment where it can act to inhibit the growth of competing fungi during the initial stages of fungal germination, i.e. largely before actual germ tubes are apparent, thus conferring an advantage to B. bassiana in out-competing susceptible competitors in the microenvironment surrounding the spore. The effects of BbAFP1 on membrane integrity were characterized and a key amino acid (F50) was shown to function in chitin binding and antifungal activity. Transgenic tomato overexpressing BbAFP1 were shown to exhibit enhanced resistance to plant fungal pathogens. Our study provides new insights into the microbial competition and genes involved in this process that can be exploited to increase plant disease resistance.
Collapse
Affiliation(s)
- Sheng Tong
- Biotechnology Research Center, Southwest University, Chongqing, P.R. China
| | - Maolian Li
- Biotechnology Research Center, Southwest University, Chongqing, P.R. China
| | - Nemat O. Keyhani
- Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, Florida, United States of America
| | - Yu Liu
- College of Biotechnology, Southwest University, Chongqing, P. R. China
| | - Min Yuan
- Biotechnology Research Center, Southwest University, Chongqing, P.R. China
| | - Dongmei Lin
- Biotechnology Research Center, Southwest University, Chongqing, P.R. China
| | - Dan Jin
- Biotechnology Research Center, Southwest University, Chongqing, P.R. China
| | - Xianbi Li
- Biotechnology Research Center, Southwest University, Chongqing, P.R. China
| | - Yan Pei
- Biotechnology Research Center, Southwest University, Chongqing, P.R. China
| | - Yanhua Fan
- Biotechnology Research Center, Southwest University, Chongqing, P.R. China
- Chongqing Key Laboratory of Plant Resource Conservation and Germplasm Innovation, Southwest University, Chongqing, P.R. China
- * E-mail:
| |
Collapse
|
8
|
Huber A, Lerchster H, Marx F. Nutrient Excess Triggers the Expression of the Penicillium chrysogenum Antifungal Protein PAFB. Microorganisms 2019; 7:microorganisms7120654. [PMID: 31817241 PMCID: PMC6956099 DOI: 10.3390/microorganisms7120654] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 11/28/2019] [Accepted: 11/29/2019] [Indexed: 12/17/2022] Open
Abstract
Nutrient limitation and nonfavorable growth conditions have been suggested to be major triggers for the expression of small, cysteine-rich antimicrobial proteins (AMPs) of fungal origin, e.g., the Penicillium chrysogenum antifungal protein (PAF), the Aspergillus giganteus antifungal protein (AFP), the Aspergillus niger antifungal protein (AnAFP). Therefore, these AMPs have been considered to be fungal secondary metabolite products. In contrast, the present study revealed that the expression of the PAF-related AMP P. chrysogenum antifungal protein B (PAFB) is strongly induced under nutrient excess during the logarithmic growth phase, whereas PAFB remained under the detection level in the supernatant of cultures grown under nutrient limitation. The efficiency of the pafB-promoter to induce PAFB expression was compared with that of two P. chrysogenum promoters that are well established for recombinant protein production: the paf-promoter and the xylose-inducible promoter of the xylanase gene, xylP. The inducibility of the pafB-promoter was superior to that of the xylP-promoter yielding comparable PAFB amounts as under the regulation of the paf-promoter. We conclude that (i) differences in the expression regulation of AMPs suggest distinct functional roles in the producer beyond their antifungal activity; and (ii) the pafB-promoter is a promising tool for recombinant protein production in P. chrysogenum, as it guarantees strong gene expression with the advantage of inducibility.
Collapse
|
9
|
Jansen RP, Beuck C, Moch M, Klein B, Küsters K, Morschett H, Wiechert W, Oldiges M. A closer look at Aspergillus: online monitoring via scattered light enables reproducible phenotyping. Fungal Biol Biotechnol 2019; 6:11. [PMID: 31396392 PMCID: PMC6681481 DOI: 10.1186/s40694-019-0073-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Accepted: 07/17/2019] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Filamentously growing microorganisms offer unique advantages for biotechnological processes, such as extraordinary secretion capacities, going along with multiple obstacles due to their complex morphology. However, limited experimental throughput in bioprocess development still hampers taking advantage of their full potential. Miniaturization and automation are powerful tools to accelerate bioprocess development, but so far the application of such technologies has mainly been focused on non-filamentous systems. During cultivation, filamentous fungi can undergo remarkable morphological changes, creating challenging cultivation conditions. Depending on the process and product, only one specific state of morphology may be advantageous to achieve e.g. optimal productivity or yield. Different approaches to control morphology have been investigated, such as microparticle enhanced cultivation. However, the addition of solid microparticles impedes the optical measurements typically used by microbioreactor systems and thus alternatives are needed. RESULTS Aspergillus giganteus IfGB 0902 was used as a model system to develop a time-efficient and robust workflow allowing microscale cultivation with increased throughput. The effect of microtiter plate geometry, shaking frequency and medium additives (talc and calcium chloride) on homogeneity of culture morphology as well as reproducibility were analyzed via online biomass measurement, microscopic imaging and cell dry weight. While addition of talc severely affected online measurements, 2% (w v-1) calcium chloride was successfully applied to obtain a highly reproducible growth behavior with homogenous morphology. Furthermore, the influence of small amounts of complex components was investigated for the applied model strain. By correlation to cell dry weight, it could be shown that optical measurements are a suitable signal for biomass concentration. However, each correlation is only applicable for a specific set of cultivation parameters. These optimized conditions were used in micro as well as lab-scale bioreactor cultivation in order to verify the reproducibility and scalability of the setup. CONCLUSION A robust workflow for A. giganteus was developed, allowing for reproducible microscale cultivation with online monitoring, where calcium chloride is an useful alternative to microparticle enhanced cultivation in order to control the morphology. Independent of the cultivation volume, comparable phenotypes were observed in microtiter plates and in lab-scale bioreactor.
Collapse
Affiliation(s)
- Roman P. Jansen
- Forschungszentrum Jülich, Institute of Bio- and Geosciences-Biotechnology (IBG-1), Jülich, Germany
| | - Carina Beuck
- Forschungszentrum Jülich, Institute of Bio- and Geosciences-Biotechnology (IBG-1), Jülich, Germany
| | - Matthias Moch
- Forschungszentrum Jülich, Institute of Bio- and Geosciences-Biotechnology (IBG-1), Jülich, Germany
| | - Bianca Klein
- Forschungszentrum Jülich, Institute of Bio- and Geosciences-Biotechnology (IBG-1), Jülich, Germany
| | - Kira Küsters
- Forschungszentrum Jülich, Institute of Bio- and Geosciences-Biotechnology (IBG-1), Jülich, Germany
| | - Holger Morschett
- Forschungszentrum Jülich, Institute of Bio- and Geosciences-Biotechnology (IBG-1), Jülich, Germany
| | - Wolfgang Wiechert
- Forschungszentrum Jülich, Institute of Bio- and Geosciences-Biotechnology (IBG-1), Jülich, Germany
- Computational Systems Biotechnology (AVT.CSB), RWTH Aachen University, Aachen, Germany
| | - Marco Oldiges
- Forschungszentrum Jülich, Institute of Bio- and Geosciences-Biotechnology (IBG-1), Jülich, Germany
- Institute of Biotechnology, RWTH Aachen University, Aachen, Germany
| |
Collapse
|
10
|
Garrigues S, Gandía M, Castillo L, Coca M, Marx F, Marcos JF, Manzanares P. Three Antifungal Proteins From Penicillium expansum: Different Patterns of Production and Antifungal Activity. Front Microbiol 2018; 9:2370. [PMID: 30344516 PMCID: PMC6182064 DOI: 10.3389/fmicb.2018.02370] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 09/18/2018] [Indexed: 01/28/2023] Open
Abstract
Antifungal proteins of fungal origin (AFPs) are small, secreted, cationic, and cysteine-rich proteins. Filamentous fungi encode a wide repertoire of AFPs belonging to different phylogenetic classes, which offer a great potential to develop new antifungals for the control of pathogenic fungi. The fungus Penicillium expansum is one of the few reported to encode three AFPs each belonging to a different phylogenetic class (A, B, and C). In this work, the production of the putative AFPs from P. expansum was evaluated, but only the representative of class A, PeAfpA, was identified in culture supernatants of the native fungus. The biotechnological production of PeAfpB and PeAfpC was achieved in Penicillium chrysogenum with the P. chrysogenum-based expression cassette, which had been proved to work efficiently for the production of other related AFPs in filamentous fungi. Western blot analyses confirmed that P. expansum only produces PeAfpA naturally, whereas PeAfpB and PeAfpC could not be detected. From the three AFPs from P. expansum, PeAfpA showed the highest antifungal activity against all fungi tested, including plant and human pathogens. P. expansum was also sensitive to its self-AFPs PeAfpA and PeAfpB. PeAfpB showed moderate antifungal activity against filamentous fungi, whereas no activity could be attributed to PeAfpC at the conditions tested. Importantly, none of the PeAFPs showed hemolytic activity. Finally, PeAfpA was demonstrated to efficiently protect against fungal infections caused by Botrytis cinerea in tomato leaves and Penicillium digitatum in oranges. The strong antifungal potency of PeAfpA, together with the lack of cytotoxicity, and significant in vivo protection against phytopathogenic fungi that cause postharvest decay and plant diseases, make PeAfpA a promising alternative compound for application in agriculture, but also in medicine or food preservation.
Collapse
Affiliation(s)
- Sandra Garrigues
- Department of Biotechnology, Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas, Valencia, Spain
| | - Mónica Gandía
- Department of Biotechnology, Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas, Valencia, Spain
| | - Laia Castillo
- Centre for Research in Agricultural Genomics (CRAG, CSIC-IRTA-UAB-UB), Barcelona, Spain
| | - María Coca
- Centre for Research in Agricultural Genomics (CRAG, CSIC-IRTA-UAB-UB), Barcelona, Spain
| | - Florentine Marx
- Division of Molecular Biology, Biocenter, Innsbruck Medical University, Innsbruck, Austria
| | - Jose F. Marcos
- Department of Biotechnology, Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas, Valencia, Spain
| | - Paloma Manzanares
- Department of Biotechnology, Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas, Valencia, Spain
| |
Collapse
|
11
|
A Computational Modeling Approach Predicts Interaction of the Antifungal Protein AFP from Aspergillus giganteus with Fungal Membranes via Its γ-Core Motif. mSphere 2018; 3:3/5/e00377-18. [PMID: 30282755 PMCID: PMC6170789 DOI: 10.1128/msphere.00377-18] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Fungal pathogens kill more people per year globally than malaria or tuberculosis and threaten international food security through crop destruction. New sophisticated strategies to inhibit fungal growth are thus urgently needed. Among the potential candidate molecules that strongly inhibit fungal spore germination are small cationic, cysteine-stabilized proteins of the AFP family secreted by a group of filamentous Ascomycetes. Its founding member, AFP from Aspergillus giganteus, is of particular interest since it selectively inhibits the growth of filamentous fungi without affecting the viability of mammalian, plant, or bacterial cells. AFPs are also characterized by their high efficacy and stability. Thus, AFP can serve as a lead compound for the development of novel antifungals. Notably, all members of the AFP family comprise a γ-core motif which is conserved in all antimicrobial proteins from pro- and eukaryotes and known to interfere with the integrity of cytoplasmic plasma membranes. In this study, we used classical molecular dynamics simulations combined with wet laboratory experiments and nuclear magnetic resonance (NMR) spectroscopy to characterize the structure and dynamical behavior of AFP isomers in solution and their interaction with fungal model membranes. We demonstrate that the γ-core motif of structurally conserved AFP is the key for its membrane interaction, thus verifying for the first time that the conserved γ-core motif of antimicrobial proteins is directly involved in protein-membrane interactions. Furthermore, molecular dynamic simulations suggested that AFP does not destroy the fungal membrane by pore formation but covers its surface in a well-defined manner, using a multistep mechanism to destroy the membranes integrity.IMPORTANCE Fungal pathogens pose a serious danger to human welfare since they kill more people per year than malaria or tuberculosis and are responsible for crop losses worldwide. The treatment of fungal infections is becoming more complicated as fungi develop resistances against commonly used fungicides. Therefore, discovery and development of novel antifungal agents are of utmost importance.
Collapse
|
12
|
Characterization of a novel cysteine-rich antifungal protein from Fusarium graminearum with activity against maize fungal pathogens. Int J Food Microbiol 2018; 283:45-51. [DOI: 10.1016/j.ijfoodmicro.2018.06.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 06/15/2018] [Accepted: 06/22/2018] [Indexed: 02/08/2023]
|
13
|
Dutta D, Debnath DAS M. Biosynthesis of Low Molecular Weight Antifungal Protein from Aspergillus giganteus in Batch Fermentation and In-Vitro Assay. Biocontrol Sci 2018; 23:41-51. [PMID: 29910208 DOI: 10.4265/bio.23.41] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
In present study, Taguchi's design of experiment L9 orthogonal array was created using Qualitek-4 software with four most critical factors namely, K2HPO4, MgSO4, CaCl2 and culture pH. Production of a new intracellular antifungal protein in submerged fermentation was optimized with yield of 0.98±0.1 mg/gram dry cell weight mycelia from Aspergillus giganteus MTCC 8408. The average molecular mass of the purified protein was figured as 5.122 kDa using Electro Spray Ionization-Mass Spectrometry. Scanning electron microscopy was used to correlate the effect of selected factors on fungal cell morphology and its metabolite production. In vitro antifungal susceptibility assay was profiled against Aspergillus niger and minimum inhibitory concentrations were in the range 0.3±0.06 µg/ml. The stronger influencing factors on afp production and mycelial biomass were noted with CaCl2 and K2HPO4 respectively. The validation experiments using optimized conditions confirmed an improvement in afp by 3.86 times with mycelial biomass by 1.52 times, compared to the basal medium. The present statistical optimization study revealed an opportunity to promote economical design at the industrial level for future scale up of effective antifungal agent against systemic aspergillosis as well as possible post harvest loss.
Collapse
Affiliation(s)
- Debashis Dutta
- School of Biochemical Engineering, Indian Institute of Technology (BHU), Varanasi (Banaras Hindu University)
| | - Mira Debnath DAS
- School of Biochemical Engineering, Indian Institute of Technology (BHU), Varanasi (Banaras Hindu University)
| |
Collapse
|
14
|
Meyer V, Jung S. Antifungal Peptides of the AFP Family Revisited: Are These Cannibal Toxins? Microorganisms 2018; 6:microorganisms6020050. [PMID: 29865265 PMCID: PMC6027536 DOI: 10.3390/microorganisms6020050] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 05/24/2018] [Accepted: 05/28/2018] [Indexed: 11/17/2022] Open
Abstract
The emergence and spread of pathogenic fungi resistant to currently used antifungal drugs represents a serious challenge for medicine and agriculture. The use of smart antimicrobials, so-called “dirty drugs” which affect multiple cellular targets, is one strategy to prevent resistance. Of special interest is the exploitation of the AFP family of antimicrobial peptides, which include its founding member AFP from Aspergillus giganteus. This latter is a highly potent inhibitor of chitin synthesis and affects plasma membrane integrity in many human and plant pathogenic fungi. A transcriptomic meta-analysis of the afp-encoding genes in A. giganteus and A. niger predicts a role for these proteins during asexual sporulation, autophagy, and nutrient recycling, suggesting that AFPs are molecules important for the survival of A. niger and A. giganteus under nutrient limitation. In this review, we discuss parallels which exist between AFPs and bacterial cannibal toxins and provide arguments that the primary function of AFPs could be to kill genetically identical siblings. We hope that this review inspires computational and experimental biologists studying alternative explanations for the nature and function of antimicrobial peptides beyond the general assumption that they are mere defense molecules to fight competitors.
Collapse
Affiliation(s)
- Vera Meyer
- Department Applied and Molecular Microbiology, Technische Universität Berlin, Institute of Biotechnology, Gustav-Meyer-Allee 25, D-13355 Berlin, Germany.
| | - Sascha Jung
- Department Applied and Molecular Microbiology, Technische Universität Berlin, Institute of Biotechnology, Gustav-Meyer-Allee 25, D-13355 Berlin, Germany.
| |
Collapse
|
15
|
Narvaez I, Khayreddine T, Pliego C, Cerezo S, Jiménez-Díaz RM, Trapero-Casas JL, López-Herrera C, Arjona-Girona I, Martín C, Mercado JA, Pliego-Alfaro F. Usage of the Heterologous Expression of the Antimicrobial Gene afp From Aspergillus giganteus for Increasing Fungal Resistance in Olive. FRONTIERS IN PLANT SCIENCE 2018; 9:680. [PMID: 29875785 PMCID: PMC5974197 DOI: 10.3389/fpls.2018.00680] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 05/03/2018] [Indexed: 05/09/2023]
Abstract
The antifungal protein (AFP) produced by Aspergillus giganteus, encoded by the afp gene, has been used to confer resistance against a broad range of fungal pathogens in several crops. In this research, transgenic olive plants expressing the afp gene under the control of the constitutive promoter CaMV35S were generated and their disease response against two root infecting fungal pathogens, Verticillium dahliae and Rosellinia necatrix, was evaluated. Embryogenic cultures derived from a mature zygotic embryo of cv. 'Picual' were used for A. tumefaciens transformation. Five independent transgenic lines were obtained, showing a variable level of afp expression in leaves and roots. None of these transgenic lines showed enhanced resistance to Verticillium wilt. However, some of the lines displayed a degree of incomplete resistance to white root rot caused by R. necatrix compared with disease reaction of non-transformed plants or transgenic plants expressing only the GUS gene. The level of resistance to this pathogen correlated with that of the afp expression in root and leaves. Our results indicate that the afp gene can be useful for enhanced partial resistance to R. necatrix in olive, but this gene does not protect against V. dahliae.
Collapse
Affiliation(s)
- Isabel Narvaez
- Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora", Departamento de Biología Vegetal, Consejo Superior de Investigaciones Científicas, Universidad de Málaga, Málaga, Spain
| | - Titouh Khayreddine
- Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora", Departamento de Biología Vegetal, Consejo Superior de Investigaciones Científicas, Universidad de Málaga, Málaga, Spain
| | | | - Sergio Cerezo
- Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora", Departamento de Biología Vegetal, Consejo Superior de Investigaciones Científicas, Universidad de Málaga, Málaga, Spain
| | - Rafael M. Jiménez-Díaz
- Departamento de Agronomía, College of Agriculture and Forestry, Universidad de Córdoba, Campus de Excelencia Internacional Agroalimentario, Edificio C-4 Celestino Mutis, Córdoba, Spain
- Instituto de Agricultura Sostenible, Consejo Superior de Investigaciones Científicas, Campus de Excelencia Internacional Agroalimentario, Córdoba, Spain
| | - José L. Trapero-Casas
- Instituto de Agricultura Sostenible, Consejo Superior de Investigaciones Científicas, Campus de Excelencia Internacional Agroalimentario, Córdoba, Spain
| | - Carlos López-Herrera
- Instituto de Agricultura Sostenible, Consejo Superior de Investigaciones Científicas, Campus de Excelencia Internacional Agroalimentario, Córdoba, Spain
| | - Isabel Arjona-Girona
- Instituto de Agricultura Sostenible, Consejo Superior de Investigaciones Científicas, Campus de Excelencia Internacional Agroalimentario, Córdoba, Spain
| | - Carmen Martín
- Departamento de Biotecnología-Biología Vegetal, ETS Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid, Madrid, Spain
| | - José A. Mercado
- Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora", Departamento de Biología Vegetal, Consejo Superior de Investigaciones Científicas, Universidad de Málaga, Málaga, Spain
| | - Fernando Pliego-Alfaro
- Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora", Departamento de Biología Vegetal, Consejo Superior de Investigaciones Científicas, Universidad de Málaga, Málaga, Spain
| |
Collapse
|
16
|
Garrigues S, Gandía M, Popa C, Borics A, Marx F, Coca M, Marcos JF, Manzanares P. Efficient production and characterization of the novel and highly active antifungal protein AfpB from Penicillium digitatum. Sci Rep 2017; 7:14663. [PMID: 29116156 PMCID: PMC5677034 DOI: 10.1038/s41598-017-15277-w] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 10/24/2017] [Indexed: 12/28/2022] Open
Abstract
Filamentous fungi encode distinct antifungal proteins (AFPs) that offer great potential to develop new antifungals. Fungi are considered immune to their own AFPs as occurs in Penicillium chrysogenum, the producer of the well-known PAF. The Penicillium digitatum genome encodes only one afp gene (afpB), and the corresponding protein (AfpB) belongs to the class B phylogenetic cluster. Previous attempts to detect AfpB were not successful. In this work, immunodetection confirmed the absence of AfpB accumulation in wild type and previous recombinant constitutive P. digitatum strains. Biotechnological production and secretion of AfpB were achieved in P. digitatum with the use of a P. chrysogenum-based expression cassette and in the yeast Pichia pastoris with the α-factor signal peptide. Both strategies allowed proper protein folding, efficient production and single-step purification of AfpB from culture supernatants. AfpB showed antifungal activity higher than the P. chrysogenum PAF against the majority of the fungi tested, especially against Penicillium species and including P. digitatum, which was highly sensitive to the self-AfpB. Spectroscopic data suggest that native folding is not required for activity. AfpB also showed notable ability to withstand protease and thermal degradation and no haemolytic activity, making AfpB a promising candidate for the control of pathogenic fungi.
Collapse
Affiliation(s)
- Sandra Garrigues
- Department of Biotechnology, Instituto de Agroquímica y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC), Paterna, Valencia, Spain
| | - Mónica Gandía
- Department of Biotechnology, Instituto de Agroquímica y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC), Paterna, Valencia, Spain
| | - Crina Popa
- Centre for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB. Edifici CRAG, Bellaterra, Barcelona, Spain
| | - Attila Borics
- Institute of Biochemistry, Biological Research Centre of Hungarian Academy of Sciences, Szeged, Hungary
| | - Florentine Marx
- Biocenter, Division of Molecular Biology, Medical University of Innsbruck, Innsbruck, Austria
| | - María Coca
- Centre for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB. Edifici CRAG, Bellaterra, Barcelona, Spain
| | - Jose F Marcos
- Department of Biotechnology, Instituto de Agroquímica y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC), Paterna, Valencia, Spain
| | - Paloma Manzanares
- Department of Biotechnology, Instituto de Agroquímica y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC), Paterna, Valencia, Spain.
| |
Collapse
|
17
|
Dutta D, Das MD. Optimization and partial characterization of intracellular anticandidal protein from Aspergillus giganteus MTCC 8408 using taguchi DOE. Bioengineered 2017; 8:536-548. [PMID: 28102738 DOI: 10.1080/21655979.2016.1264539] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
A new intracellular antifungal protein (afp) production with average molecular weight 24.3 kDa and yield of 0.65 ± 0.1 mg/gram dry cell weight (gdcw) of mycelia in submerged fermentation of Aspergillus giganteus MTCC 8408 was optimized. Taguchi's DOE (design of experiment) L27 orthogonal array (OA) was constructed using Qualitek-4 software with 8 most influensive factors namely, culture pH, temperature, slant age, inoculum volume, agitation and KH2PO4. Scanning electron microscopy (SEM) was used to correlate the effect of selected factors on fungal cell morphology and afp production. The crude protein purification was accomplished using pure ammonium sulfate fractionation followed by carboxymethyl cellulose (CMC) ion-exchange chromatography and sephadex G-100 gel filtration. The average molecular mass of the purified protein was figured by silver stained SDS (sodium dodecylsulphate)-PAGE (poly-acryl amide gel electrophoresis). In vitro antifungal susceptibility assay was profiled against Candida albicans NCIM 3471 and minimum inhibitory concentrations (MICs) were in the range 3 to 4 µg/ml. Characterization of protein was observed with FTIR (Fourier transform infrared spectroscopy) analysis. The optimal production condition for crude afp was obtained as follows: soluble starch: 20 g/l; Corn steep liquor (CSL, 2%) + proteose peptone (PP, 1%): 30 g/l; pH: 5.8; temperature: 25°C; slant age: 3 d; inoculum size: 5% (v/v); agitation: 180 rpm; KH2PO4: 0.1 g/l. The validation experiments using optimized conditions confirmed an improvement in afp production by 59.4% against the expected enhancement of afp production by 61.22%. The present statistical optimization study revealed an opportunity to promote economical design at the industrial level for future scale up of effective antifungal agent against opportunistic oral and vaginal infection.
Collapse
Affiliation(s)
- Debashis Dutta
- a School of Biochemical Engineering , Indian Institute of Technology, Varanasi, Banaras Hindu University , India
| | - Mira Debnath Das
- a School of Biochemical Engineering , Indian Institute of Technology, Varanasi, Banaras Hindu University , India
| |
Collapse
|
18
|
Tian Z, Wang R, Ambrose KV, Clarke BB, Belanger FC. The Epichloë festucae antifungal protein has activity against the plant pathogen Sclerotinia homoeocarpa, the causal agent of dollar spot disease. Sci Rep 2017; 7:5643. [PMID: 28717232 PMCID: PMC5514056 DOI: 10.1038/s41598-017-06068-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 06/07/2017] [Indexed: 02/05/2023] Open
Abstract
Epichloë spp. are naturally occurring fungal endophytic symbionts of many cool-season grasses. Infection by the fungal endophytes often confers biotic and abiotic stress tolerance to their hosts. Endophyte-mediated disease resistance is well-established in the fine fescue grass Festuca rubra subsp. rubra (strong creeping red fescue) infected with E. festucae. Resistance to fungal pathogens is not an established effect of endophyte infection of other grass species, and may therefore be unique to the fine fescues. The underlying mechanism of the disease resistance is unknown. E. festucae produces a secreted antifungal protein that is highly expressed in the infected plant tissues and may therefore be involved in the disease resistance. Most Epichloë spp. do not have a gene for a similar antifungal protein. Here we report the characterization of the E. festucae antifungal protein, designated Efe-AfpA. The antifungal protein partially purified from the apoplastic proteins of endophyte-infected plant tissue and the recombinant protein expressed in the yeast Pichia pastoris was found to have activity against the important plant pathogen Sclerotinia homoeocarpa. Efe-AfpA may therefore be a component of the disease resistance seen in endophyte-infected strong creeping red fescue.
Collapse
Affiliation(s)
- Zipeng Tian
- Department of Plant Biology, Rutgers University, New Brunswick, New Jersey, 08901, USA
| | - Ruying Wang
- Department of Plant Biology, Rutgers University, New Brunswick, New Jersey, 08901, USA
| | - Karen V Ambrose
- Department of Plant Biology, Rutgers University, New Brunswick, New Jersey, 08901, USA
- Indigo Agriculture, Charlestown, Massachusetts, 02129, USA
| | - Bruce B Clarke
- Department of Plant Biology, Rutgers University, New Brunswick, New Jersey, 08901, USA
| | - Faith C Belanger
- Department of Plant Biology, Rutgers University, New Brunswick, New Jersey, 08901, USA.
| |
Collapse
|
19
|
Wanka F, Arentshorst M, Cairns TC, Jørgensen T, Ram AFJ, Meyer V. Highly active promoters and native secretion signals for protein production during extremely low growth rates in Aspergillus niger. Microb Cell Fact 2016; 15:145. [PMID: 27544686 PMCID: PMC4992228 DOI: 10.1186/s12934-016-0543-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 08/08/2016] [Indexed: 01/06/2023] Open
Abstract
Background The filamentous ascomycete Aspergillus niger is used in many industrial processes for the production of enzymes and organic acids by batch and fed-batch cultivation. An alternative technique is continuous cultivation, which promises improved yield and optimized pipeline efficiency. Results In this work, we have used perfusion (retentostat) cultivation to validate two promoters that are suitable for A. niger continuous cultivation of industrially relevant products. Firstly, promoters of genes encoding either an antifungal protein (Panafp) or putative hydrophobin (PhfbD) were confirmed as active throughout retentostat culture by assessing mRNA and protein levels using a luciferase (mluc) reporter system. This demonstrated the anafp promoter mediates a high but temporally variable expression profile, whereas the hfbD promoter mediates a semi-constant, moderate-to-high protein expression during retentostat culture. In order to assess whether these promoters were suitable to produce heterologous proteins during retentostat cultivation, the secreted antifungal protein (AFP) from Aspergillus giganteus, which has many potential biotechnological applications, was expressed in A. niger during retentostat cultivation. Additionally, this assay was used to concomitantly validate that native secretion signals encoded in anafp and hfbD genes can be harnessed for secretion of heterologous proteins. Afp mRNA and protein abundance were comparable to luciferase measurements throughout retentostat cultivation, validating the use of Panafp and PhfbD for perfusion cultivation. Finally, a gene encoding the highly commercially relevant thermal hysteresis protein (THP) was expressed in this system, which did not yield detectable protein. Conclusion Both hfbD and anafp promoters are suitable for production of useful products in A. niger during perfusion cultivation. These findings provide a platform for further optimisations for high production of heterologous proteins with industrial relevance. Electronic supplementary material The online version of this article (doi:10.1186/s12934-016-0543-2) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Franziska Wanka
- Department Applied and Molecular Microbiology, Institute of Biotechnology, Berlin University of Technology, Gustav-Meyer-Allee 25, 13355, Berlin, Germany
| | - Mark Arentshorst
- Department Molecular Microbiology and Biotechnology, Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE, Leiden, The Netherlands
| | - Timothy C Cairns
- Department Applied and Molecular Microbiology, Institute of Biotechnology, Berlin University of Technology, Gustav-Meyer-Allee 25, 13355, Berlin, Germany
| | - Thomas Jørgensen
- Protein Expression, Novo Nordisk, Novo Nordisk Park, 2760, Måløv, Denmark
| | - Arthur F J Ram
- Department Molecular Microbiology and Biotechnology, Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE, Leiden, The Netherlands
| | - Vera Meyer
- Department Applied and Molecular Microbiology, Institute of Biotechnology, Berlin University of Technology, Gustav-Meyer-Allee 25, 13355, Berlin, Germany.
| |
Collapse
|
20
|
Occurrence and function of fungal antifungal proteins: a case study of the citrus postharvest pathogen Penicillium digitatum. Appl Microbiol Biotechnol 2015; 100:2243-56. [DOI: 10.1007/s00253-015-7110-3] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 10/06/2015] [Accepted: 10/16/2015] [Indexed: 10/22/2022]
|
21
|
Purification and characterization of a novel antifungal protein secreted by Penicillium chrysogenum from an Arctic sediment. Appl Microbiol Biotechnol 2013; 97:10381-90. [PMID: 23474616 DOI: 10.1007/s00253-013-4800-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2013] [Revised: 02/16/2013] [Accepted: 02/19/2013] [Indexed: 10/27/2022]
Abstract
A fungal strain, Penicillium chrysogenum A096, was isolated from an Arctic sediment sample. Its culture supernatant inhibited mycelial growth of some plant pathogenic fungi. After saturation of P. chrysogenum A096 culture supernatant with ammonium sulfate and ion exchange chromatography, a novel antifungal protein (Pc-Arctin) was purified and identified by matrix assisted laser desorption ionization-time of flight-time of flight-mass spectrometry (MALDI-TOF-TOF-MS). The gene encoding for Pc-Arctin consisting of 195 nucleotides was cloned from P. chrysogenum A096 to confirm the mass spectrometry result. Pc-Arctin displays antifungal activity against Paecilomyces variotii, Alternaria longipes, and Trichoderma viride at minimum inhibitory concentrations (MIC) of 24, 48, and 192 ng/disc, respectively. Pc-Arctin was most sensitive to proteinase K and then to trypsin but insensitive to papain. Pc-Arctin possesses high thermostability and cannot be antagonized by common surfactants, except for sodium dodecyl sulfate (SDS). Divalent ions, such as Mn(2+), Mg(2+), and Zn(2+), inhibited the antifungal activity of Pc-Arctin. Hemagglutination assays showed that Pc-Arctin had no hemagglutinating or hemolytic activity against red blood cells (RBC) from rabbits, rats, and guinea pigs. Therefore, Pc-Arctin from Arctic P. chrysogenum may represent a novel antifungal protein with potential for application in controlling plant pathogenic fungal infection.
Collapse
|
22
|
Hegedüs N, Marx F. Antifungal proteins: More than antimicrobials? FUNGAL BIOL REV 2013; 26:132-145. [PMID: 23412850 PMCID: PMC3569713 DOI: 10.1016/j.fbr.2012.07.002] [Citation(s) in RCA: 135] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 07/30/2012] [Accepted: 07/31/2012] [Indexed: 01/01/2023]
Abstract
Antimicrobial proteins (AMPs) are widely distributed in nature. In higher eukaryotes, AMPs provide the host with an important defence mechanism against invading pathogens. AMPs of lower eukaryotes and prokaryotes may support successful competition for nutrients with other microorganisms of the same ecological niche. AMPs show a vast variety in structure, function, antimicrobial spectrum and mechanism of action. Most interestingly, there is growing evidence that AMPs also fulfil important biological functions other than antimicrobial activity. The present review focuses on the mechanistic function of small, cationic, cysteine-rich AMPs of mammals, insects, plants and fungi with antifungal activity and specifically aims at summarizing current knowledge concerning additional biological properties which opens novel aspects for their future use in medicine, agriculture and biotechnology.
Collapse
Affiliation(s)
| | - Florentine Marx
- Corresponding author. Tel.: +43 512 9003 70207; fax: +43 512 9003 73100.
| |
Collapse
|
23
|
Seibold M, Wolschann P, Bodevin S, Olsen O. Properties of the bubble protein, a defensin and an abundant component of a fungal exudate. Peptides 2011; 32:1989-95. [PMID: 21906643 DOI: 10.1016/j.peptides.2011.08.022] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2011] [Revised: 08/23/2011] [Accepted: 08/23/2011] [Indexed: 11/23/2022]
Abstract
Colonies of the ascomycete fungus Penicillium brevicompactum Dierckx produce bright yellow-green fluorescent exudate bubbles on its surface when grown on standard plant cell culture medium. According to SDS-PAGE analysis, the exudate is enriched in one protein, named bubble protein (BP). Detailed characteristics of BP are described, and also its corresponding genomic promoter and terminator sequences that flank sequences encoding signal peptide and a precursor sequence upstream of that of the mature protein. Following on previous work, the protein is now biochemically characterized. BP, the structure of which mainly consists of beta sheets, has four very stable disulfide bridges that resist standard procedures for reduction. With such traits, BP can now be categorized as a new member of the ever growing class of defensins. Indeed, the protein revealed anti-fungal effects as it inhibits growth of the yeast Saccharomyces cerevisiae in a dose-dependent manner. Structural classification places BP into the group of proteins with a knottin fold, founding the BP superfamily. Based on genomic alignments that revealed very high homology to four proteins of related fungi, a 3D structure prediction of the corresponding proteins was made. In addition, it was discovered that the closely related fungus Penicillium chrysogenum encodes a BP homolog - in addition to its PAF protein, which also is similar to BP - further suggesting that fungi may possess more than one defensin.
Collapse
Affiliation(s)
- Marcus Seibold
- University of Vienna, Institute of Theoretical Chemistry, Vienna, Austria
| | | | | | | |
Collapse
|
24
|
Binder U, Bencina M, Eigentler A, Meyer V, Marx F. The Aspergillus giganteus antifungal protein AFPNN5353 activates the cell wall integrity pathway and perturbs calcium homeostasis. BMC Microbiol 2011; 11:209. [PMID: 21943024 PMCID: PMC3197501 DOI: 10.1186/1471-2180-11-209] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Accepted: 09/23/2011] [Indexed: 01/25/2023] Open
Abstract
Background The antifungal protein AFPNN5353 is a defensin-like protein of Aspergillus giganteus. It belongs to a group of secretory proteins with low molecular mass, cationic character and a high content of cysteine residues. The protein inhibits the germination and growth of filamentous ascomycetes, including important human and plant pathogens and the model organsims Aspergillus nidulans and Aspergillus niger. Results We determined an AFPNN5353 hypersensitive phenotype of non-functional A. nidulans mutants in the protein kinase C (Pkc)/mitogen-activated protein kinase (Mpk) signalling pathway and the induction of the α-glucan synthase A (agsA) promoter in a transgenic A. niger strain which point at the activation of the cell wall integrity pathway (CWIP) and the remodelling of the cell wall in response to AFPNN5353. The activation of the CWIP by AFPNN5353, however, operates independently from RhoA which is the central regulator of CWIP signal transduction in fungi. Furthermore, we provide evidence that calcium (Ca2+) signalling plays an important role in the mechanistic function of this antifungal protein. AFPNN5353 increased about 2-fold the cytosolic free Ca2+ ([Ca2+]c) of a transgenic A. niger strain expressing codon optimized aequorin. Supplementation of the growth medium with CaCl2 counteracted AFPNN5353 toxicity, ameliorated the perturbation of the [Ca2+]c resting level and prevented protein uptake into Aspergillus sp. cells. Conclusions The present study contributes new insights into the molecular mechanisms of action of the A. giganteus antifungal protein AFPNN5353. We identified its antifungal activity, initiated the investigation of pathways that determine protein toxicity, namely the CWIP and the Ca2+ signalling cascade, and studied in detail the cellular uptake mechanism in sensitive target fungi. This knowledge contributes to define new potential targets for the development of novel antifungal strategies to prevent and combat infections of filamentous fungi which have severe negative impact in medicine and agriculture.
Collapse
Affiliation(s)
- Ulrike Binder
- Biocenter, Division of Molecular Biology, Innsbruck Medical University, Fritz-Pregl Strasse 3, Innsbruck, A-6020, Austria
| | | | | | | | | |
Collapse
|
25
|
Hegedus N, Leiter E, Kovács B, Tomori V, Kwon NJ, Emri T, Marx F, Batta G, Csernoch L, Haas H, Yu JH, Pócsi I. The small molecular mass antifungal protein of Penicillium chrysogenum--a mechanism of action oriented review. J Basic Microbiol 2011; 51:561-71. [PMID: 21780144 DOI: 10.1002/jobm.201100041] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Accepted: 04/02/2011] [Indexed: 12/16/2022]
Abstract
The β-lactam producing filamentous fungus Penicillium chrysogenum secretes a 6.25 kDa small molecular mass antifungal protein, PAF, which has a highly stable, compact 3D structure and is effective against a wide spectrum of plant and zoo pathogenic fungi. Its precise physiological functions and mode of action need to be elucidated before considering possible biomedical, agricultural or food technological applications. According to some more recent experimental data, PAF plays an important role in the fine-tuning of conidiogenesis in Penicillium chrysogenum. PAF triggers apoptotic cell death in sensitive fungi, and cell death signaling may be transmitted through two-component systems, heterotrimeric G protein coupled signal transduction and regulatory networks as well as via alteration of the Ca(2+) -homeostasis of the cells. Possible biotechnological applications of PAF are also outlined in the review.
Collapse
Affiliation(s)
- Nikoletta Hegedus
- Department of Microbial Biotechnology and Cell Biology, Faculty of Science and Technology, Centre of Arts, Humanities and Sciences, University of Debrecen, Debrecen, Hungary
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
26
|
Hegedüs N, Sigl C, Zadra I, Pócsi I, Marx F. The paf gene product modulates asexual development in Penicillium chrysogenum. J Basic Microbiol 2011; 51:253-62. [PMID: 21298690 PMCID: PMC3103751 DOI: 10.1002/jobm.201000321] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2010] [Accepted: 11/11/2010] [Indexed: 01/31/2023]
Abstract
Penicillium chrysogenum secretes a low molecular weight, cationic and cysteine-rich protein (PAF). It has growth inhibitory activity against the model organism Aspergillus nidulans and numerous zoo- and phytopathogenic fungi but shows only minimal conditional antifungal activity against the producing organism itself. In this study we provide evidence for an additional function of PAF which is distinct from the antifungal activity against putative ecologically concurrent microorganisms. Our data indicate that PAF enhances conidiation in P. chrysogenum by modulating the expression of brlA, the central regulatory gene for mitospore development. A paf deletion strain showed a significant impairment of mitospore formation which sustains our hypothesis that PAF plays an important role in balancing asexual differentiation in P. chrysogenum.
Collapse
Affiliation(s)
- Nikoletta Hegedüs
- Biocenter, Division of Molecular Biology, Innsbruck Medical UniversityInnsbruck, Austria
- Department of Microbial Biotechnology and Cell Biology, Faculty of Science and Technology, University of DebrecenDebrecen, Hungary
| | | | | | - Istvan Pócsi
- Department of Microbial Biotechnology and Cell Biology, Faculty of Science and Technology, University of DebrecenDebrecen, Hungary
| | - Florentine Marx
- Biocenter, Division of Molecular Biology, Innsbruck Medical UniversityInnsbruck, Austria
| |
Collapse
|
27
|
Transcriptomic insights into the physiology of Aspergillus niger approaching a specific growth rate of zero. Appl Environ Microbiol 2010; 76:5344-55. [PMID: 20562270 DOI: 10.1128/aem.00450-10] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The physiology of filamentous fungi at growth rates approaching zero has been subject to limited study and exploitation. With the aim of uncoupling product formation from growth, we have revisited and improved the retentostat cultivation method for Aspergillus niger. A new retention device was designed allowing reliable and nearly complete cell retention even at high flow rates. Transcriptomic analysis was used to explore the potential for product formation at very low specific growth rates. The carbon- and energy-limited retentostat cultures were highly reproducible. While the specific growth rate approached zero (<0.005 h(-1)), the growth yield stabilized at a minimum (0.20 g of dry weight per g of maltose). The severe limitation led to asexual differentiation, and the supplied substrate was used for spore formation and secondary metabolism. Three physiologically distinct phases of the retentostat cultures were subjected to genome-wide transcriptomic analysis. The severe substrate limitation and sporulation were clearly reflected in the transcriptome. The transition from vegetative to reproductive growth was characterized by downregulation of genes encoding secreted substrate hydrolases and cell cycle genes and upregulation of many genes encoding secreted small cysteine-rich proteins and secondary metabolism genes. Transcription of known secretory pathway genes suggests that A. niger becomes adapted to secretion of small cysteine-rich proteins. The perspective is that A. niger cultures as they approach a zero growth rate can be used as a cell factory for production of secondary metabolites and cysteine-rich proteins. We propose that the improved retentostat method can be used in fundamental studies of differentiation and is applicable to filamentous fungi in general.
Collapse
|
28
|
Rodríguez-Martín A, Acosta R, Liddell S, Núñez F, Benito MJ, Asensio MA. Characterization of the novel antifungal protein PgAFP and the encoding gene of Penicillium chrysogenum. Peptides 2010; 31:541-7. [PMID: 19914321 DOI: 10.1016/j.peptides.2009.11.002] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2009] [Revised: 11/04/2009] [Accepted: 11/04/2009] [Indexed: 11/24/2022]
Abstract
The strain RP42C from Penicillium chrysogenum produces a small protein PgAFP that inhibits the growth of some toxigenic molds. The molecular mass of the protein determined by electrospray ionization mass spectrometry (ESI-MS) was 6 494Da. PgAFP showed a cationic character with an estimated pI value of 9.22. Upon chemical and enzymatic treatments of PgAFP, no evidence for N- or O-glycosylations was obtained. Five partial sequences of PgAFP were obtained by Edman degradation and by ESI-MS/MS after trypsin and chymotrypsin digestions. Using degenerate primers from these peptide sequences, a segment of 70bp was amplified by PCR from pgafp gene. 5'- and 3'-ends of pgafp were obtained by RACE-PCR with gene-specific primers designed from the 70bp segment. The complete pgafp sequence of 404bp was obtained using primers designed from 5'- and 3'-ends. Comparison of genomic and cDNA sequences revealed a 279bp coding region interrupted by two introns of 63 and 62bp. The precursor of the antifungal protein consists of 92 amino acids and appears to be processed to the mature 58 amino acids PgAFP. The deduced amino acid sequence of the mature protein shares 79% identity to the antifungal protein Anafp from Aspergillus niger. PgAFP is a new protein that belongs to the group of small, cysteine-rich, and basic proteins with antifungal activity produced by ascomycetes. Given that P. chrysogenum is regarded as safe mold commonly found in foods, PgAFP may be useful to prevent growth of toxigenic molds in food and agricultural products.
Collapse
Affiliation(s)
- Andrea Rodríguez-Martín
- Higiene y Seguridad Alimentaria, Facultad de Veterinaria, Universidad de Extremadura, Avda. de la Universidad, 10071 Cáceres, Spain
| | | | | | | | | | | |
Collapse
|
29
|
Holz CM, Stahl U. Ribosomally synthesized antimicrobial peptides in prokaryotic and eukaryotic organisms. FOOD BIOTECHNOL 2009. [DOI: 10.1080/08905439509549888] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
30
|
Skouri-Gargouri H, Jellouli-Chaker N, Gargouri A. Factors affecting production and stability of the AcAFP antifungal peptide secreted by Aspergillus clavatus. Appl Microbiol Biotechnol 2009; 86:535-43. [DOI: 10.1007/s00253-009-2279-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2009] [Revised: 09/24/2009] [Accepted: 09/25/2009] [Indexed: 10/20/2022]
|
31
|
Skouri-Gargouri H, Ben Ali M, Gargouri A. Molecular cloning, structural analysis and modelling of the AcAFP antifungal peptide from Aspergillus clavatus. Peptides 2009; 30:1798-804. [PMID: 19591888 DOI: 10.1016/j.peptides.2009.06.034] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2009] [Revised: 06/25/2009] [Accepted: 06/26/2009] [Indexed: 11/17/2022]
Abstract
An abundantly secreted thermostable peptide (designed AcAFP) with a molecular mass of 5777 Da was isolated and purified in a previous work from a local strain of A. clavatus (VR1). Based on the N-terminal amino acid (aa) sequence of the AcAFP peptide, an oligonucleotide probe was derived and allowed the amplification of the encoding cDNA by RT-PCR. This cDNA fragment encodes a pre-pro-protein of 94 aa which appears to be processed to a mature product of 51 aa cys-rich protein. The deduced aa sequence of the pre-pro-sequence reveals high similarity with ascomycetes antifungal peptide. Comparison of the nucleotide sequence of the genomic fragment and the cDNA clone revealed the presence of an open reading frame of 282 bp interrupted by two small introns of 89 and 56 bp with conserved splice site. The three-dimensional (3D) structure modeling of AcAFP exhibits a compact structure consisting of five anti-parallel beta barrel stabilized by four internal disulfide bridges. The folding pattern revealed also a cationic site and spatially adjacent hydrophobic stretch. The antifungal mechanism was investigated by transmission and confocal microscopy. AcAFP cause cell wall altering in a dose-dependent manner against the phytopathogenic fungus Fusarium oxysporum.
Collapse
Affiliation(s)
- Houda Skouri-Gargouri
- Laboratoire de Génétique Moléculaire des Eucaryotes, Centre de Biotechnologie de Sfax, Route Sidi Mansour, BP K 3038-Sfax, Tunisia
| | | | | |
Collapse
|
32
|
Acosta R, Rodríguez-Martín A, Martín A, Núñez F, Asensio MA. Selection of antifungal protein-producing molds from dry-cured meat products. Int J Food Microbiol 2009; 135:39-46. [DOI: 10.1016/j.ijfoodmicro.2009.07.020] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2009] [Revised: 07/13/2009] [Accepted: 07/19/2009] [Indexed: 11/27/2022]
|
33
|
Batta G, Barna T, Gáspári Z, Sándor S, Kövér KE, Binder U, Sarg B, Kaiserer L, Chhillar AK, Eigentler A, Leiter É, Hegedüs N, Pócsi I, Lindner H, Marx F. Functional aspects of the solution structure and dynamics of PAF--a highly-stable antifungal protein from Penicillium chrysogenum. FEBS J 2009; 276:2875-90. [PMID: 19459942 PMCID: PMC4290664 DOI: 10.1111/j.1742-4658.2009.07011.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Penicillium antifungal protein (PAF) is a promising antimycotic without toxic effects on mammalian cells and therefore may represent a drug candidate against the often lethal Aspergillus infections that occur in humans. The pathogenesis of PAF on sensitive fungi involves G-protein coupled signalling followed by apoptosis. In the present study, the solution structure of this small, cationic, antifungal protein from Penicillium chrysogenum is determined by NMR. We demonstrate that PAF belongs to the structural classification of proteins fold class of its closest homologue antifungal protein from Aspergillus giganteus. PAF comprises five beta-strands forming two orthogonally packed beta-sheets that share a common interface. The ambiguity in the assignment of two disulfide bonds out of three was investigated by NMR dynamics, together with restrained molecular dynamics calculations. The clue could not be resolved: the two ensembles with different disulfide patterns and the one with no S-S bond exhibit essentially the same fold. (15)N relaxation dispersion and interference experiments did not reveal disulfide bond rearrangements via slow exchange. The measured order parameters and the 3.0 ns correlation time are appropriate for a compact monomeric protein of this size. Using site-directed mutagenesis, we demonstrate that the highly-conserved and positively-charged lysine-rich surface region enhances the toxicity of PAF. However, the binding capability of the oligosaccharide/oligonucleotide binding fold is reduced in PAF compared to antifungal protein as a result of less solvent-exposed aromatic regions, thus explaining the absence of chitobiose binding. The present study lends further support to the understanding of the documented substantial differences between the mode of action of two highly homologous antifungal proteins.
Collapse
Affiliation(s)
- Gyula Batta
- Department of Biochemistry, Centre of Arts, Humanities and Sciences, University of Debrecen, Egyetem tér 1, H-4010 Debrecen, Hungary
| | - Teréz Barna
- Department of Biochemistry, Centre of Arts, Humanities and Sciences, University of Debrecen, Egyetem tér 1, H-4010 Debrecen, Hungary
| | - Zoltán Gáspári
- Institute of Chemistry, Eötvös Loránd University, Pázmány P. s. 1/A, H-1117, Budapest, Hungary
| | - Szabolcs Sándor
- Department of Biochemistry, Centre of Arts, Humanities and Sciences, University of Debrecen, Egyetem tér 1, H-4010 Debrecen, Hungary
| | - Katalin E. Kövér
- Department of Inorganic and Analytical Chemistry, Centre of Arts, Humanities and Sciences, University of Debrecen, Egyetem tér 1, H-4010 Debrecen, Hungary
| | - Ulrike Binder
- Division of Molecular Biology, Biocenter, Innsbruck Medical University, Fritz-Pregl Strasse 3, A-6020 Innsbruck, Austria
| | - Bettina Sarg
- Division of Clinical Biochemistry, Biocenter, Innsbruck Medical University, Fritz-Pregl Strasse 3, A-6020 Innsbruck, Austria
| | - Lydia Kaiserer
- Division of Molecular Biology, Biocenter, Innsbruck Medical University, Fritz-Pregl Strasse 3, A-6020 Innsbruck, Austria
| | - Anil Kumar Chhillar
- Division of Molecular Biology, Biocenter, Innsbruck Medical University, Fritz-Pregl Strasse 3, A-6020 Innsbruck, Austria
| | - Andrea Eigentler
- Division of Molecular Biology, Biocenter, Innsbruck Medical University, Fritz-Pregl Strasse 3, A-6020 Innsbruck, Austria
| | - Éva Leiter
- Department of Microbial Biotechnology and Cell Biology, Centre of Arts, Humanities and Sciences, University of Debrecen, Egyetem tér 1, H-4010 Debrecen, Hungary
| | - Nikoletta Hegedüs
- Department of Microbial Biotechnology and Cell Biology, Centre of Arts, Humanities and Sciences, University of Debrecen, Egyetem tér 1, H-4010 Debrecen, Hungary
| | - István Pócsi
- Department of Microbial Biotechnology and Cell Biology, Centre of Arts, Humanities and Sciences, University of Debrecen, Egyetem tér 1, H-4010 Debrecen, Hungary
| | - Herbert Lindner
- Division of Clinical Biochemistry, Biocenter, Innsbruck Medical University, Fritz-Pregl Strasse 3, A-6020 Innsbruck, Austria
| | - Florentine Marx
- Division of Molecular Biology, Biocenter, Innsbruck Medical University, Fritz-Pregl Strasse 3, A-6020 Innsbruck, Austria
| |
Collapse
|
34
|
Skouri-Gargouri H, Gargouri A. First isolation of a novel thermostable antifungal peptide secreted by Aspergillus clavatus. Peptides 2008; 29:1871-7. [PMID: 18687373 DOI: 10.1016/j.peptides.2008.07.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2008] [Revised: 07/04/2008] [Accepted: 07/07/2008] [Indexed: 11/26/2022]
Abstract
A novel antifungal peptide produced by an indigenous fungal strain (VR) of Aspergillus clavatus was purified. The antifungal peptide was enriched in the supernatant after heat treatment at 70 degrees C. The thermostable character was exploited in the first purification step, as purified peptide was obtained after ultrafiltration and reverse phase-HPLC on C18 column application. The purified peptide named "AcAFP" for A. clavatus antifungal peptide, has molecular mass of 5773Da determined by MALDI-ToF spectrometry. The N-terminal sequence showed a notable identity to the limited family of antifungal peptides produced by ascomycetes fungi. The AcAFP activity remains intact even after heat treatment at 100 degrees C for 1h confirming its thermostability. It exhibits a strong inhibitory activity against mycelial growth of several serious human and plant pathogenic fungi: Fusariuym oxysporum, Fusarium solani, Aspergillus niger, Botrytis cinerea, Alternaria solani, whereas AcAFP did not affect yeast and bacterial growth.
Collapse
Affiliation(s)
- Houda Skouri-Gargouri
- Laboratoire de Génétique Moléculaire des Eucaryotes, Centre de Biotechnologie de Sfax, BP "K" 3038-Sfax, Tunisia
| | | |
Collapse
|
35
|
Meyer V. A small protein that fights fungi: AFP as a new promising antifungal agent of biotechnological value. Appl Microbiol Biotechnol 2007; 78:17-28. [PMID: 18066545 DOI: 10.1007/s00253-007-1291-3] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2007] [Revised: 11/14/2007] [Accepted: 11/15/2007] [Indexed: 11/28/2022]
Abstract
As fungal infections are becoming more prevalent in the medical or agricultural fields, novel and more efficient antifungal agents are badly needed. Within the scope of developing new strategies for the management of fungal infections, antifungal compounds that target essential fungal cell wall components are highly preferable. Ideally, newly developed antimycotics should also combine major aspects such as sustainability, high efficacy, limited toxicity and low costs of production. A naturally derived molecule that possesses all the desired characteristics is the antifungal protein (AFP) secreted by the filamentous ascomycete Aspergillus giganteus. AFP is a small, basic and cysteine-rich peptide that exerts extremely potent antifungal activity against human- and plant-pathogenic fungi without affecting the viability of bacteria, yeast, plant and mammalian cells. This review summarises the current knowledge of the structure, mode of action and expression of AFP, and highlights similarities and differences concerning these issues between AFP and its related proteins from other Ascomycetes. Furthermore, the potential use of AFP in the combat against fungal contaminations and infections will be discussed.
Collapse
Affiliation(s)
- Vera Meyer
- TU Berlin, Institut für Biotechnologie, Fachgebiet Mikrobiologie und Genetik, Gustav-Meyer-Allee 25, 13355, Berlin, Germany.
| |
Collapse
|
36
|
Girgi M, Breese WA, Lörz H, Oldach KH. Rust and downy mildew resistance in pearl millet (Pennisetum glaucum) mediated by heterologous expression of the afp gene from Aspergillus giganteus. Transgenic Res 2007; 15:313-24. [PMID: 16779647 DOI: 10.1007/s11248-006-0001-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2005] [Accepted: 01/06/2006] [Indexed: 11/25/2022]
Abstract
The cDNA encoding the antifungal protein AFP from the mould Aspergillus giganteus was introduced into two pearl millet (Pennisetum glaucum) genotypes by particle bombardment. Stable integration and expression of the afp gene was confirmed in two independent transgenic T0 plants and their progeny using Southern blot and RT-PCR analysis. In vitro infection of detached leaves and in vivo inoculation of whole plants with the basidomycete Puccinia substriata, the causal agent of rust disease, and the oomycete Sclerospora graminicola, causal agent of downy mildew, resulted in a significant reduction of disease symptoms in comparison to wild type control plants. The disease resistance of pearl millet was increased by up to 90% when infected with two diverse, economically important pathogens. This is the first report of genetic enhancement of Pennisetum glaucum against fungal infections.
Collapse
Affiliation(s)
- Maram Girgi
- Developmental Biology and Biotechnology, Biocenter Klein Flottbek, University of Hamburg, Ohnhorststr. 18, 22609 Hamburg, Germany.
| | | | | | | |
Collapse
|
37
|
Szappanos H, Szigeti GP, Pál B, Rusznák Z, Szucs G, Rajnavölgyi E, Balla J, Balla G, Nagy E, Leiter E, Pócsi I, Hagen S, Meyer V, Csernoch L. The antifungal protein AFP secreted by Aspergillus giganteus does not cause detrimental effects on certain mammalian cells. Peptides 2006; 27:1717-25. [PMID: 16500727 DOI: 10.1016/j.peptides.2006.01.009] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2005] [Revised: 01/12/2006] [Accepted: 01/17/2006] [Indexed: 11/15/2022]
Abstract
The antifungal protein AFP is a small, cystein-rich protein secreted by the imperfect ascomycete Aspergillus giganteus. The protein efficiently inhibits the growth of filamentous fungi, including a variety of serious human and plant pathogens mainly of the genera Aspergillus and Fusarium, whereas AFP does not affect the growth of yeast and bacteria. This restricted susceptibility range makes it very attractive for medical or biotechnological use to combat fungal infection and contamination. We, therefore, analyzed whether AFP affects the growth or function of a number of mammalian cells. Here we show that the protein neither provokes any cytotoxic effects on human endothelial cells isolated from the umbilical vein nor activates the immune system. Moreover, potassium currents of neurons and astrocytes do not change in the presence of AFP and neither excitatory processes nor the intracellular calcium homeostasis of cultured skeletal muscle myotubes are affected by AFP. Our data, therefore, suggest that AFP is indeed a promising candidate for the therapeutic or biotechnological use as a potential antifungal agent.
Collapse
Affiliation(s)
- Henrietta Szappanos
- Department of Physiology, RCMM, MHSC, University of Debrecen, 98 Nagyerdei krt., Debrecen 4012, Hungary
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
38
|
Mueller D, Stahl U, Meyer V. Application of hammerhead ribozymes in filamentous fungi. J Microbiol Methods 2006; 65:585-95. [PMID: 16298445 DOI: 10.1016/j.mimet.2005.10.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2005] [Revised: 10/11/2005] [Accepted: 10/11/2005] [Indexed: 11/25/2022]
Abstract
Metabolic engineering in filamentous fungi is a emerging field of research as many fungi produce high value primary and secondary metabolites. Ribozyme technology can be used as a tool for metabolic engineering to influence metabolic pathways and to knock down the expression of specific genes of interest. Hammerhead ribozymes can target virtually any mRNA sequence of choice and prevent gene expression on the post-transcriptional level. They are thus a versatile tool for timed and spatial elimination of unwanted gene products. As current research has only investigated the application of ribozymes in bacteria, yeast and mammalian cells, we decided to carry out a study on whether this technology can also function with filamentous fungi. We employed a sensitive, quantitative reporter-based model system as a proof of concept, using the Escherichia coli beta-glucuronidase transcript (uidA) as the target mRNA and Aspergillus giganteus as the host. This system was used to validate the in vivo activities of seven different hammerhead ribozymes, which were selected by in silico analysis of the uidA mRNA. All ribozymes tested were able to reduce the reporter activity up to a maximum of 100%, demonstrating that ribozyme technology is indeed a useful tool in fungal metabolic engineering.
Collapse
Affiliation(s)
- Dirk Mueller
- Technische Universität Berlin, Institut für Biotechnologie, Fachgebiet Mikrobiologie und Genetik, Germany
| | | | | |
Collapse
|
39
|
Meyer V, Spielvogel A, Funk L, Tilburn J, Arst HN, Stahl U. Alkaline pH-induced up-regulation of the afp gene encoding the antifungal protein (AFP) of Aspergillus giganteus is not mediated by the transcription factor PacC: possible involvement of calcineurin. Mol Genet Genomics 2005; 274:295-306. [PMID: 16133167 DOI: 10.1007/s00438-005-0002-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2005] [Accepted: 04/22/2005] [Indexed: 10/25/2022]
Abstract
The afp gene encoding the antifungal protein (AFP) of Aspergillus giganteus has a prototypical alkaline gene expression pattern, which suggests that the gene might be under the control of the ambient pH-dependent zinc-finger transcription factor PacC. This notion is corroborated by the presence in the upstream region of afp of two putative PacC binding sites, afpP1 and afpP2, which are specifically recognised by the PacC protein of A. nidulans in vitro. However, in this report we provide several lines of evidence to show that pH-dependent up-regulation of afp is not mediated by transcriptional activation through PacC. (1) The temporal expression pattern of the A. giganteus pacC gene does not parallel the accumulation of the afp mRNA during cultivation. (2) Inactivation of afpP1 and afpP2 did not reduce promoter activity under alkaline conditions, as determined from the relative wild-type and mutant afp::lacZ reporter activities in A. nidulans. (3) Reporter activities in acidity- and alkalinity-mimicking mutant strains are inconsistent with a positive role for PacC in afp expression. (4) In A. giganteus, the pH-dependent increase in afp mRNA and AFP levels can be completely prevented by the calcineurin inhibitor FK506, suggesting that the calcineurin signalling pathway might control the in vivo activation of the afp promoter by alkaline pH.
Collapse
Affiliation(s)
- Vera Meyer
- Institut für Biotechnologie, Fachgebiet Mikrobiologie und Genetik, Technische Universität Berlin, Germany.
| | | | | | | | | | | |
Collapse
|
40
|
Szappanos H, Szigeti GP, Pál B, Rusznák Z, Szucs G, Rajnavölgyi E, Balla J, Balla G, Nagy E, Leiter E, Pócsi I, Marx F, Csernoch L. The Penicillium chrysogenum-derived antifungal peptide shows no toxic effects on mammalian cells in the intended therapeutic concentration. Naunyn Schmiedebergs Arch Pharmacol 2005; 371:122-32. [PMID: 15702351 DOI: 10.1007/s00210-004-1013-7] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2004] [Accepted: 12/01/2004] [Indexed: 11/24/2022]
Abstract
Certain filamentous fungi, such as the penicillin-producing strain Penicillium chrysogenum, secrete small, highly basic and cysteine-rich proteins with antifungal effects. Affected fungi include a number of important zoopathogens, including those infecting humans. Recent studies, however, have pointed to a membrane-perturbing effect of these antifungal compounds, apparent as a potassium efflux from affected fungal cells. If present on mammalian cells, this would severely hinder the potential therapeutic use of these molecules. Here we studied the effects of the P. chrysogenum-derived antifungal peptide (PAF) on a number of mammalian cells to establish whether the protein has any cytotoxic effects, alters transmembrane currents on excitable cells or activates the immune system. PAF, in a concentration range of 2-100 mug/ml, did not cause any cytotoxicity on human endothelial cells from the umbilical vein. Applied at 10 mug/ml, it also failed to modify voltage-gated potassium channels of neurones, skeletal muscle fibers, and astrocytes. PAF also left the hyperpolarization-activated non-specific cationic current (I(h)) and the L-type calcium current unaffected. Finally, up to 2 mug/ml, PAF did not induce the production of pro-inflammatory cytokines such as IL-6, IL-8, and TNF-alpha. These results suggest that PAF should have only minor, if any, effects on mammalian cells in the intended therapeutic concentration range.
Collapse
Affiliation(s)
- Henrietta Szappanos
- Department of Physiology, RCMM, MHSC, University of Debrecen, P.O. Box 22, Debrecen, Hungary
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
41
|
Marx F, Salvenmoser W, Kaiserer L, Graessle S, Weiler-Görz R, Zadra I, Oberparleiter C. Proper folding of the antifungal protein PAF is required for optimal activity. Res Microbiol 2005; 156:35-46. [PMID: 15636746 DOI: 10.1016/j.resmic.2004.07.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2004] [Accepted: 07/13/2004] [Indexed: 10/26/2022]
Abstract
The Penicillium chrysogenumantifungal protein PAF is secreted into the supernatant after elimination of a preprosequence. PAF is actively internalized into the hyphae of sensitive molds and provokes growth retardation as well as changes in morphology. Thus far, no information is available on the exact mode of action of PAF, nor on the function of its prosequence in protein activity. Therefore, we sought to investigate the effects of secreted PAF as well as of intracellularly retained pro-PAF and mature PAF on the sensitive ascomycete Aspergillus nidulans, and transformed this model organism by expression vectors containing 5'-sequentially truncated paf-coding sequences under the control of the inducible P. chrysogenum-derived xylanase promoter. Indirect immunofluorescence staining revealed the localization of recombinant PAF predominantly in the hyphal tips of the transformant Xylpaf1 which expressed prepro-PAF, whereas the protein was found to be distributed intracellularly within all segments of hyphae of the transformants Xylpaf2 and Xylpaf3 which expressed pro-PAF and mature PAF, respectively. Growth retardation of Xylpaf1 and Xylpaf3 hyphae was detected by proliferation assays and by light microscopy analysis. Using transmission electron microscopy of ultrathin hyphal sections a marked alteration of the mitochondrial ultrastructure in Xylpaf1 was observed and an elevated amount of carbonylated proteins pointed to severe oxidative stress in this strain. The effects induced by secreted recombinant PAF resembled those evoked by native PAF. The results give evidence that properly folded PAF is a prerequisite for its activity.
Collapse
Affiliation(s)
- Florentine Marx
- Department of Molecular Biology, Medical University of Innsbruck, Peter-Mayr Strasse 4B/III, 6020 Innsbruck, Austria.
| | | | | | | | | | | | | |
Collapse
|
42
|
Oberparleiter C, Kaiserer L, Haas H, Ladurner P, Andratsch M, Marx F. Active internalization of the Penicillium chrysogenum antifungal protein PAF in sensitive aspergilli. Antimicrob Agents Chemother 2004; 47:3598-601. [PMID: 14576124 PMCID: PMC253792 DOI: 10.1128/aac.47.11.3598-3601.2003] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Penicillium chrysogenum antifungal protein PAF inhibits the growth of various filamentous fungi. In this study, PAF was found to localize to the cytoplasm of sensitive aspergilli by indirect immunofluorescence staining. The internalization process required active metabolism and ATP and was prevented by latrunculin B, suggesting an endocytotic mechanism.
Collapse
|
43
|
Abstract
The peptides and proteins secreted by fungi are reviewed in this article. They include ribosome inactivating peptides and proteins, antifungal peptides and proteins, lectins, ubiquitin-like peptides and proteins, peptides and proteins with nucleolytic activity, proteases, xylanases, cellulases, sugar oxidoreductases, laccases, invertases, trehalose phosphorylases, and various enzymes with applications in food industry, chemical production and the medical sector.
Collapse
Affiliation(s)
- T B Ng
- Department of Biochemistry, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| |
Collapse
|
44
|
Xu J, Gong ZZ. Intron requirement for AFP gene expression in Trichoderma viride. MICROBIOLOGY-SGM 2004; 149:3093-3097. [PMID: 14600221 DOI: 10.1099/mic.0.26514-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The 430 bp ORF of the Aspergillus giganteus antifungal protein (AFP) gene, containing two small introns, was fused between the promoter and the terminator of the Aspergillus nidulans trpC gene. The AFP gene in this vector produced detectable levels of spliced mRNA in Trichoderma viride. In contrast, in the same vector configuration, its 285 bp intronless derivative showed no accumulation of mRNA when transformed into T. viride. Such expression results were confirmed at the protein level. This fact demonstrated that the introns were required for AFP gene expression in T. viride. This is thought to be a novel phenomenon found in filamentous fungi. Although the mechanism of splicing in filamentous fungi might be similar to that in other eukaryotes, little is known of how it affects expression. This study suggests that the small introns in filamentous fungal genes may not only act as intervening elements, but may also play crucial roles in gene expression by affecting mRNA accumulation. Furthermore, it may provide new evidence for intron-dependent evolution.
Collapse
Affiliation(s)
- Jun Xu
- State Key Laboratory of Molecular Biology, Box 16, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, PR China
| | - Zhen Zhen Gong
- State Key Laboratory of Molecular Biology, Box 16, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, PR China
| |
Collapse
|
45
|
Theis T, Wedde M, Meyer V, Stahl U. The antifungal protein from Aspergillus giganteus causes membrane permeabilization. Antimicrob Agents Chemother 2003; 47:588-93. [PMID: 12543664 PMCID: PMC151754 DOI: 10.1128/aac.47.2.588-593.2003] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We investigated the inhibitory effects of the antifungal protein (AFP) from Aspergillus giganteus on the growth of several filamentous fungi. For this purpose, the MICs of AFP were determined and ranged from 0.1 micro g/ml for Fusarium oxysporum to 200 micro g/ml for Aspergillus nidulans. The antifungal activity of AFP was diminished in the presence of cations. We were able to show that incubation of AFP-sensitive fungi with the protein resulted in membrane permeabilization using an assay based on the uptake of the fluorescent dye SYTOX Green. No permeabilization by AFP could be detected at concentrations below the species-specific MIC. Furthermore, AFP-induced permeabilization could readily be detected after 5 min of incubation. Localization experiments with fluorescein isothiocyanate-labeled AFP and immunofluorescence staining with an AFP-specific antibody supported the observation that the protein interacts with membranes. After treatment of AFP-sensitive fungi with AFP, the protein was localized at the plasma membrane, whereas it was mainly detected inside the cells of AFP-resistant fungi. We conclude from these data that the growth-inhibitory effect of AFP is caused by permeabilization of the fungal membranes.
Collapse
Affiliation(s)
- T Theis
- Technische Universität Berlin, Institut für Biotechnologie, Fachgebiet Mikrobiologie und Genetik, 13355 Berlin, Germany
| | | | | | | |
Collapse
|
46
|
Martinez Del Pozo A, Lacadena V, Mancheno JM, Olmo N, Onaderra M, Gavilanes JG. The antifungal protein AFP of Aspergillus giganteus is an oligonucleotide/oligosaccharide binding (OB) fold-containing protein that produces condensation of DNA. J Biol Chem 2002; 277:46179-83. [PMID: 12351633 DOI: 10.1074/jbc.m207472200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The antifungal protein AFP is a small polypeptide of 51 amino acid residues secreted by Aspergillus giganteus. Its potent activity against phytopathogenic fungi converts AFP in a promising tool in plant protection. However, no data have been reported regarding the mode of action of AFP. The three-dimensional structure of this protein, a small and compact beta barrel composed of five highly twisted antiparallel beta strands, displays the characteristic features of the oligonucleotide/oligosaccharide binding (OB fold) structural motif. A comparison of the structures of AFP and OB fold-containing proteins shows this structural similarity despite the absence of any significant sequence similarity. AFP, like most OB fold-containing proteins, binds nucleic acids. The protein promotes charge neutralization and condensation of DNA as demonstrated by electrophoretic mobility shift and ethidium bromide displacement assays. Nucleic acid produces quenching of the protein fluorescence emission. This nucleic acid interacting ability of AFP may be related to the antifungal activity of this small polypeptide.
Collapse
Affiliation(s)
- Alvaro Martinez Del Pozo
- Departamento de Bioquimica y Biologia Molecular, Facultad de Quimica, Universidad Complutense, 28040 Madrid, Spain.
| | | | | | | | | | | |
Collapse
|
47
|
Meyer V, Stahl U. New insights in the regulation of the afp gene encoding the antifungal protein of Aspergillus giganteus. Curr Genet 2002; 42:36-42. [PMID: 12420144 DOI: 10.1007/s00294-002-0324-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2002] [Revised: 07/26/2002] [Accepted: 08/12/2002] [Indexed: 11/30/2022]
Abstract
The antifungal protein (AFP) secreted by the mould Aspergillus giganteus is a small, highly basic polypeptide with antifungal activity. Previous work has shown that transcription of the corresponding afp gene is regulated by ambient pH, being suppressed under acidic and strongly induced under alkaline conditions. This observation suggested that the afp gene is regulated by the wide-domain transcriptional factor PacC. Here, we show that two putative PacC binding sites within the afp promoter, denoted afpP1 and afpP2, are efficiently recognised in vitro by a PacC fusion protein of A. nidulans. In addition, we found that phosphate, which was used as a buffering agent during cultivation, plays an important role in regulating afp expression. AFP production was nearly completely inhibited in the presence of external phosphate. The results of Northern analysis indicate that the inhibitory effect of phosphate is mediated at the transcriptional level.
Collapse
Affiliation(s)
- Vera Meyer
- Technische Universität Berlin, Institut für Biotechnologie, Fachgebiet Mikrobiologie und Genetik, Gustav-Meyer-Allee 25, 13355 Berlin, Germany.
| | | |
Collapse
|
48
|
Pócsi I, Sámi L, Leiter E, Majoros L, Szabó B, Emri T, Pusztahelyi T. Searching for new-type antifungal drugs (an outline for possible new strategies). Acta Microbiol Immunol Hung 2002; 48:533-43. [PMID: 11791350 DOI: 10.1556/amicr.48.2001.3-4.19] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
New approaches for treatment of invasive fungal infections are necessary to cope with emerging resistant fungal pathogens of humans. In this paper, three different strategies are presented and evaluated to find new-type antifungal drugs and their targets. While experimental data obtained with potent chitinase inhibitors, e.g. allosamidin, and small-size antifungal proteins of fungal origin are encouraging more efforts are needed to verify and exploit the possible involvement of intracellular thiols, e.g. glutathione, and their metabolic enzymes in the pathogenesis of mycoses caused by dimorphic fungi. Chitinase inhibitors seem to hinder the cell separation of yeasts and the fragmentation of filamentous fungi quite effectively and, hence, they may be implicated in future therapies of systemic mycoses. In addition, small-size antifungal proteins possessing a broad inhibition spectrum may also provide us with promising new agents for the treatment of different kinds of (e.g. cutaneous) fungal infections.
Collapse
Affiliation(s)
- I Pócsi
- Department of Microbiology and Biotechnology, Faculty of Sciences, University of Debrecen, P.O. Box 63, H-4010 Debrecen, Hungary
| | | | | | | | | | | | | |
Collapse
|
49
|
Liu RS, Huang H, Yang Q, Liu WY. Purification of alpha-sarcin and an antifungal protein from mold (Aspergillus giganteus) by chitin affinity chromatography. Protein Expr Purif 2002; 25:50-8. [PMID: 12071698 DOI: 10.1006/prep.2001.1608] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A simple method for preparation of alpha-sarcin and an antifungal protein (AFP) from mold (Aspergillus giganteus MDH 18894) has been developed. alpha-Sarcin and AFP were purified simultaneously by chitin affinity column chromatography and gel filtration. By this method, 4.5 mg of pure alpha-sarcin and 6.9 mg of pure AFP were obtained from 2 liters of culture medium. Compared with other purification methods such as ion-exchange column chromatography, this procedure was very simple and specific. The purified alpha-sarcin and AFP were homogeneous as characterized by SDS-polyacrylamide gel electrophoresis. Both alpha-sarcin and AFP exhibited the binding activity to generated chitin. Soluble glycochitin decreased the intensity of fluorescence of alpha-sarcin and made the lambda(em)m shift from 340 to 347 nm. Titration of alpha-sarcin with N-bromosuccinimide under native conditions revealed that two tryptophans (Trps) were all located in the core part of alpha-sarcin molecule. This indicated that Trps were not involved in the binding of alpha-sarcin to chitin. Glycochitin in the culture medium increased the expression of alpha-sarcin, while it had no effect on the expression of AFP. Unlike other ligands such as Cibacron blue for the affinity purification of alpha-sarcin and AFP, glycochitin increased the nuclease activity of alpha-sarcin.
Collapse
Affiliation(s)
- Ren-shui Liu
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, 320 Yue-Yang Road, Shanghai 200031, China
| | | | | | | |
Collapse
|
50
|
Oldach KH, Becker D, Lörz H. Heterologous expression of genes mediating enhanced fungal resistance in transgenic wheat. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2001; 14:832-8. [PMID: 11437256 DOI: 10.1094/mpmi.2001.14.7.832] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Three cDNAs encoding the antifungal protein Ag-AFP from the fungus Aspergillus giganteus, a barley class II chitinase and a barley type I RIP, all regulated by the constitutive Ubiquitin1 promoter from maize, were expressed in transgenic wheat. In 17 wheat lines, stable integration and inheritance of one of the three transgenes has been demonstrated over four generations. The formation of powdery mildew (Erysiphe graminis f. sp. tritici) or leaf rust (Puccinia recondita f. sp. tritici) colonies was significantly reduced on leaves from afp or chitinase II- but not from rip I-expressing wheat lines compared with non-transgenic controls. The increased resistance of afp and chitinase II lines was dependent on the dose of fungal spores used for inoculation. Heterologous expression of the fungal afp gene and the barley chitinase II gene in wheat demonstrated that colony formation and, thereby, spreading of two important biotrophic fungal diseases is inhibited approximately 40 to 50% at an inoculum density of 80 to 100 spores per cm2.
Collapse
Affiliation(s)
- K H Oldach
- Institute for Applied Molecular Plant Biology, AMPII, University of Hamburg, Germany
| | | | | |
Collapse
|