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The Role of the Glutathione System in Stress Adaptation, Morphogenesis and Virulence of Pathogenic Fungi. Int J Mol Sci 2022; 23:ijms231810645. [PMID: 36142553 PMCID: PMC9500636 DOI: 10.3390/ijms231810645] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 09/09/2022] [Accepted: 09/10/2022] [Indexed: 11/17/2022] Open
Abstract
Morphogenesis and stress adaptation are key attributes that allow fungal pathogens to thrive and infect human hosts. During infection, many fungal pathogens undergo morphological changes, and this ability is highly linked to virulence. Furthermore, pathogenic fungi have developed multiple antioxidant defenses to cope with the host-derived oxidative stress produced by phagocytes. Glutathione is a major antioxidant that can prevent cellular damage caused by various oxidative stressors. While the role of glutathione in stress detoxification is known, studies of the glutathione system in fungal morphological switching and virulence are lacking. This review explores the role of glutathione metabolism in fungal adaptation to stress, morphogenesis, and virulence. Our comprehensive analysis of the fungal glutathione metabolism reveals that the role of glutathione extends beyond stressful conditions. Collectively, glutathione and glutathione-related proteins are necessary for vitality, cellular development and pathogenesis.
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Gevi F, Leo P, Cassaro A, Pacelli C, de Vera JPP, Rabbow E, Timperio AM, Onofri S. Metabolomic Profile of the Fungus Cryomyces antarcticus Under Simulated Martian and Space Conditions as Support for Life-Detection Missions on Mars. Front Microbiol 2022; 13:749396. [PMID: 35633719 PMCID: PMC9133366 DOI: 10.3389/fmicb.2022.749396] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 03/14/2022] [Indexed: 11/29/2022] Open
Abstract
The identification of traces of life beyond Earth (e.g., Mars, icy moons) is a challenging task because terrestrial chemical-based molecules may be destroyed by the harsh conditions experienced on extraterrestrial planetary surfaces. For this reason, studying the effects on biomolecules of extremophilic microorganisms through astrobiological ground-based space simulation experiments is significant to support the interpretation of the data that will be gained and collected during the ongoing and future space exploration missions. Here, the stability of the biomolecules of the cryptoendolithic black fungus Cryomyces antarcticus, grown on two Martian regolith analogues and on Antarctic sandstone, were analysed through a metabolomic approach, after its exposure to Science Verification Tests (SVTs) performed in the frame of the European Space Agency (ESA) Biology and Mars Experiment (BIOMEX) project. These tests are building a set of ground-based experiments performed before the space exposure aboard the International Space Station (ISS). The analysis aimed to investigate the effects of different mineral mixtures on fungal colonies and the stability of the biomolecules synthetised by the fungus under simulated Martian and space conditions. The identification of a specific group of molecules showing good stability after the treatments allow the creation of a molecular database that should support the analysis of future data sets that will be collected in the ongoing and next space exploration missions.
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Affiliation(s)
- Federica Gevi
- Department of Ecological and Biological Sciences (DEB), University of Tuscia, Viterbo, Italy
| | - Patrick Leo
- Department of Ecological and Biological Sciences (DEB), University of Tuscia, Viterbo, Italy
- Department of Environmental Sciences, Informatics and Statistics, University Ca’ Foscari of Venice, Venice, Italy
| | - Alessia Cassaro
- Department of Ecological and Biological Sciences (DEB), University of Tuscia, Viterbo, Italy
| | | | | | - Elke Rabbow
- German Aerospace Centre, Institute of Aerospace Medicine (DLR), Cologne, Germany
| | - Anna Maria Timperio
- Department of Ecological and Biological Sciences (DEB), University of Tuscia, Viterbo, Italy
| | - Silvano Onofri
- Department of Ecological and Biological Sciences (DEB), University of Tuscia, Viterbo, Italy
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Slepecky RA, Starmer WT. Phenotypic plasticity in fungi: a review with observations onAureobasidium pullulans. Mycologia 2017; 101:823-32. [DOI: 10.3852/08-197] [Citation(s) in RCA: 97] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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4
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Pullulan production and physiological characteristics of Aureobasidium pullulans under acid stress. Appl Microbiol Biotechnol 2013; 97:8069-77. [DOI: 10.1007/s00253-013-5094-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 06/30/2013] [Accepted: 07/01/2013] [Indexed: 10/26/2022]
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Gostinčar C, Muggia L, Grube M. Polyextremotolerant black fungi: oligotrophism, adaptive potential, and a link to lichen symbioses. Front Microbiol 2012; 3:390. [PMID: 23162543 PMCID: PMC3492852 DOI: 10.3389/fmicb.2012.00390] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Accepted: 10/22/2012] [Indexed: 11/13/2022] Open
Abstract
Black meristematic fungi can survive high doses of radiation and are resistant to desiccation. These adaptations help them to colonize harsh oligotrophic habitats, e.g., on the surface and subsurface of rocks. One of their most characteristic stress-resistance mechanisms is the accumulation of melanin in the cell walls. This, production of other protective molecules and a plastic morphology further contribute to ecological flexibility of black fungi. Increased growth rates of some species after exposure to ionizing radiation even suggest yet unknown mechanisms of energy production. Other unusual metabolic strategies may include harvesting UV or visible light or gaining energy by forming facultative lichen-like associations with algae or cyanobacteria. The latter is not entirely surprising, since certain black fungal lineages are phylogenetically related to clades of lichen-forming fungi. Similar to black fungi, lichen-forming fungi are adapted to growth on exposed surfaces with low availability of nutrients. They also efficiently use protective molecules to tolerate frequent periods of extreme stress. Traits shared by both groups of fungi may have been important in facilitating the evolution and radiation of lichen-symbioses.
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Affiliation(s)
- Cene Gostinčar
- Department of Biology, Biotechnical Faculty, University of LjubljanaLjubljana, Slovenia
- Centre of Excellence for Integrated Approaches in Chemistry and Biology of ProteinsLjubljana, Slovenia
| | - Lucia Muggia
- Institute of Plant Sciences, Karl-Franzens-University GrazGraz, Austria
- Department of Life Science, University of TriesteTrieste, Italy
| | - Martin Grube
- Institute of Plant Sciences, Karl-Franzens-University GrazGraz, Austria
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Sierra-Campos E, Valdez-Solana MA, Matuz-Mares D, Velázquez I, Pardo JP. Induction of morphological changes in Ustilago maydis cells by octyl gallate. Microbiology (Reading) 2009; 155:604-611. [DOI: 10.1099/mic.0.020800-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The effects of octyl gallate on Ustilago maydis yeast cells were analysed in relation to its capacity to oxidize compounds (pro-oxidant actions). All phenolic compounds tested inhibited the alternative oxidase (AOX). However, only octyl gallate induced a morphological change in yeast cells and collapsed the mitochondrial membrane potential. In contrast to octyl gallate, propyl gallate and nordihydroguaiaretic acid caused only a negligible cell change and the membrane potential was not affected. Our findings show that structurally related phenolic compounds do not necessarily exert similar actions on target cells. Preincubation of U. maydis cells with trolox inhibited the change to pseudohyphal growth produced by octyl gallate. These results suggest that in addition to the inhibitory action of octyl gallate on the AOX, this compound induces a switch from yeast to a mycelium, probably through the formation of lipid peroxides.
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Affiliation(s)
- E. Sierra-Campos
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Apartado Postal 70-159, Coyoacán 04510, México D. F., Mexico
| | - M. A. Valdez-Solana
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, IPN, Casco de Santo Tomas, Mexico
| | - D. Matuz-Mares
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Apartado Postal 70-159, Coyoacán 04510, México D. F., Mexico
| | - I. Velázquez
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Apartado Postal 70-159, Coyoacán 04510, México D. F., Mexico
| | - J. P. Pardo
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Apartado Postal 70-159, Coyoacán 04510, México D. F., Mexico
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Abstract
It has been known for many years that oxygen (O2) may have toxic effects on aerobically growing microorganisms, mainly due to the threat arising from reactive oxygen species (ROS). In submerged culture industrial fermentation processes, maintenance of adequate levels of O2 (usually measured as dissolved oxygen tension (DOT)) can often be critical to the success of the manufacturing process. In viscous cultures of filamentous cultures, actively respiring, supplying adequate levels of O2 to the cultures by conventional air sparging is difficult and various strategies have been adopted to improve or enhance O2 transfer. However, adoption of those strategies to maintain adequate levels of DOT, that is, to avoid O2 limitation, may expose the fungi to potential oxidative damage caused by enhanced flux through the respiratory system. In the past, there have been numerous studies investigating the effects of DOT on fungal bioprocesses. Generally, in these studies moderately enhanced levels of O2 supply resulted in improvement in growth, product formation and acceptable morphological changes, while the negative impact of higher levels of DOT on morphology and product synthesis were generally assumed to be a consequence of "oxidative stress." However, very little research has actually been focused on investigation of this implicit link, and the mechanisms by which such effects might be mediated within industrial fungal processes. To elucidate this neglected topic, this review first surveys the basic knowledge of the chemistry of ROS, defensive systems in fungi and the effects of DOT on fungal growth, metabolism and morphology. The physiological responses of fungal cells to oxidative stress imposed by artificial and endogenous stressors are then critically reviewed. It is clear that fungi have a range of methods available to minimize the negative impacts of elevated ROS, but also that development of the various defensive systems or responses, can itself have profound consequences upon many process-related parameters. It is also clear that many of the practically convenient and widely used experimental methods of simulating oxidative stress, for example, addition of exogenous menadione or hydrogen peroxide, have effects on fungal cultures quite distinct from the effects of elevated levels of O2, and care must thus be exercised in the interpretation of results from such studies. The review critically evaluates our current understanding of the responses of fungal cultures to elevated O2 levels, and highlights key areas requiring further research to remedy gaps in knowledge.
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Affiliation(s)
- Zhonghu Bai
- Strathclyde Fermentation Center, Department of Bioscience, Strathclyde University, Glasgow, UK
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Pócsi I, Molnár Z, Pusztahelyi T, Varecza Z, Emri T. Yeast-like cell formation and glutathione metabolism in autolysing cultures of Penicillium chrysogenum. ACTA BIOLOGICA HUNGARICA 2007; 58:431-40. [PMID: 18277469 DOI: 10.1556/abiol.58.2007.4.10] [Citation(s) in RCA: 5] [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
The bulk formation of yeast-like (arthrospore-like) cells were typical in carbon-depleted submerged cultures of the high beta-lactam producer Penicillium chrysogenum NCAIM 00237 strain independently of the nitrogen-content of the culture medium. This morphogenetic switch was still quite common in carbon-starving cultures of the low-penicillin-producer strain P. chrysogenum ATCC 28089 (Wis 54-1255) when the nitrogen-content of the medium was low but was a very rare event in wild-type P. chrysogenum cultures. The mycelium-->yeast-like cell transition correlated well with a relatively high glutathione concentration and a reductive glutathione/glutathione disulfite (GSH/GSSG) redox balance in autolysing cultures, which was a consequence of industrial strain development. Paradoxically, the development of high beta-lactam productivity resulted in a high intracellular GSH level and, concomitantly, in an increased y-glutamyltranspeptidase (i.e. GSH-decomposing) activity in the autolytic phase of growth of P. chrysogenum NCAIM 00237. The hypothesized causal connection between GSH metabolism and cell morphology, if verified, may help us in future metabolic engineering of industrially important filamentous fungi.
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Affiliation(s)
- I Pócsi
- Department of Microbial Biotechnology and Cell Biology, Faculty of Sciences, University of Debrecen, Debrecen, Hungary
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González-Párraga P, Marín FR, Argüelles JC, Hernández JA. Correlation between the intracellular content of glutathione and the formation of germ-tubes induced by human serum in Candida albicans. Biochim Biophys Acta Gen Subj 2005; 1722:324-30. [PMID: 15777624 DOI: 10.1016/j.bbagen.2005.01.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2004] [Revised: 12/02/2004] [Accepted: 01/04/2005] [Indexed: 10/25/2022]
Abstract
The physiological role of the tripeptide glutathione (GSH) and its oxidized form (GSSG) was investigated during the initial steps of dimorphism (formation of germ-tubes), which is induced by human serum in exponential yeast-like cells (blastoconidia) of the Candida albicans strain CAI-4 (wild type) and its congenic tps1/tps1 mutant, deficient in trehalose synthesis. The content of glutathione, measured both as GSH and the ratio GSH/GSSG, underwent a moderate drop in parallel with the induction of a significant degree of germ-tube emergence. Whereas the supply of exogenous glutathione did not affect the degree of dimorphic transition, depletion of intracellular glutathione by addition of 1-chloro-2,4 dinitrobenzene (CDNB) caused a clear reduction in the percentage of hyphae formation; although this effect must be due to the severe cell mortality produced by CDNB. Simultaneous measurements of GSH-metabolizing activities revealed a moderate decrease of glutathione reductase concomitant with the activation of glutathione peroxidase. In turn, catalase activity did not show noticeable changes. The putative correlation between the redox status of glutathione and the dimorphic conversion in C. albicans is discussed.
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Affiliation(s)
- Pilar González-Párraga
- Area de Microbiología, Facultad de Biología, Universidad de Murcia, Campus de Espinardo, E-30071 Murcia, Spain
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Abstract
Glutathione (GSH; gamma-L-glutamyl-L-cysteinyl-glycine), a non-protein thiol with a very low redox potential (E'0 = 240 mV for thiol-disulfide exchange), is present in high concentration up to 10 mM in yeasts and filamentous fungi. GSH is concerned with basic cellular functions as well as the maintenance of mitochondrial structure, membrane integrity, and in cell differentiation and development. GSH plays key roles in the response to several stress situations in fungi. For example, GSH is an important antioxidant molecule, which reacts non-enzymatically with a series of reactive oxygen species. In addition, the response to oxidative stress also involves GSH biosynthesis enzymes, NADPH-dependent GSH-regenerating reductase, glutathione S-transferase along with peroxide-eliminating glutathione peroxidase and glutaredoxins. Some components of the GSH-dependent antioxidative defence system confer resistance against heat shock and osmotic stress. Formation of protein-SSG mixed disulfides results in protection against desiccation-induced oxidative injuries in lichens. Intracellular GSH and GSH-derived phytochelatins hinder the progression of heavy metal-initiated cell injuries by chelating and sequestering the metal ions themselves and/or by eliminating reactive oxygen species. In fungi, GSH is mobilized to ensure cellular maintenance under sulfur or nitrogen starvation. Moreover, adaptation to carbon deprivation stress results in an increased tolerance to oxidative stress, which involves the induction of GSH-dependent elements of the antioxidant defence system. GSH-dependent detoxification processes concern the elimination of toxic endogenous metabolites, such as excess formaldehyde produced during the growth of the methylotrophic yeasts, by formaldehyde dehydrogenase and methylglyoxal, a by-product of glycolysis, by the glyoxalase pathway. Detoxification of xenobiotics, such as halogenated aromatic and alkylating agents, relies on glutathione S-transferases. In yeast, these enzymes may participate in the elimination of toxic intermediates that accumulate in stationary phase and/or act in a similar fashion as heat shock proteins. GSH S-conjugates may also form in a glutathione S-transferases-independent way, e.g. through chemical reaction between GSH and the antifugal agent Thiram. GSH-dependent detoxification of penicillin side-chain precursors was shown in Penicillium sp. GSH controls aging and autolysis in several fungal species, and possesses an anti-apoptotic feature.
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Affiliation(s)
- István Pócsi
- Department of Microbiology and Biotechnology, Faculty of Sciences, University of Debrecen, P.O. Box 63, H-4010 Debrecen, Hungary
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11
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Nagy MA, Emri T, Fekete E, Sándor E, Springael JY, Penninckx MJ, Pócsi I. Glutathione metabolism of Acremonium chrysogenum in relation to cephalosporin C production: is gamma-glutamyltransferase in the center? Folia Microbiol (Praha) 2003; 48:149-55. [PMID: 12800495 DOI: 10.1007/bf02930947] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Methionine increased the intracellular glutathione (reduced) (GSH) pool and the specific gamma-glutamyltransferase (gamma-GT) activity in the cephalosporin C (CPC) producer Acremonium chrysogenum. The accelerated turnover of GSH might be indicative of the existence of a functioning gamma-glutamate cycle, and might supply the CPC biosynthetic machinery with L-cysteine. The gamma-GT was not subject to nitrogen metabolic repression but was more active in cells exposed to different oxidative-stress-generating agents. Exogenous cysteine hindered both the uptake of methionine and the induction of gamma-GT, and was not beneficial for CPC production. There was no causal relationship between the redox status of the cells and the observed cell morphology.
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Affiliation(s)
- M A Nagy
- Department of Microbiology and Biotechnology, Faculty of Sciences, University of Debrecen, 4010 Debrecen, Hungary
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Emri T, Oláh B, Sámi L, Molnár Z, Nagy M, Pusztahelyi T, Pócsi I. Investigation of glutathione metabolism in filamentous fungi (a short auto-review). Acta Microbiol Immunol Hung 2003; 49:267-76. [PMID: 12109157 DOI: 10.1556/amicr.49.2002.2-3.13] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- T Emri
- Department of Microbiology and Biotechnology, Faculty of Sciences, University of Debrecen, Egyetem tér 1, H-4010 Debrecen, Hungary
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Pócsi I, Emri T, Sámi L, Leiter E, Szentirmai A. The glutathione metabolism of the beta-lactam producer filamentous fungus Penicillium chrysogenum. Acta Microbiol Immunol Hung 2002; 48:393-411. [PMID: 11791340 DOI: 10.1556/amicr.48.2001.3-4.9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Glutathione (gamma-L-glutamyl-L-cysteinyl-glycine; GSH) shares structural similarities with the beta-lactam biosynthetic intermediate ACV-tripeptide (delta-(L-alpha-aminoadipyl)-L-cysteinyl-D-valine). Not surprisingly, GSH has been reported to inhibit the beta-lactam biosynthetic machinery quite effectively and, hence, strategies to decrease the intracellular GSH concentrations without influencing negatively the physiological status of idiophasic mycelia would attract industrial interests. Here we present a detailed map of the GSH metabolic network of P. chrysogenum and show a promising way to keep the GSH pool selectively down under penicillin producing conditions. This procedure includes a well-controlled and transient lowering of pH at the beginning of the production phase, and it relies on the GSH-dependent detoxification of the protonophore penicillin side-chain precursors phenoxyacetic acid (POA) and phenylacetic acid (PA). Encouraging preliminary fed-batch fermentation experiments have been performed to test this technological proposal. Interestingly, the mechanism of the activation of POA and PA to the appropriate CoA derivatives has remained yet to be answered but the involvement of GSH seems to be rather unlikely in this case. Our data also challenge the hypothesis that the formation of different kinds of penicillins would be an alternative to GSH-dependent detoxification processes in P. chrysogenum.
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Affiliation(s)
- I Pócsi
- Department of Microbiology and Biotechnology, Faculty of Sciences, University of Debrecen, P.O. Box 63, H-4010 Debrecen, Hungary
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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: 0.4] [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.
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Affiliation(s)
- I Pócsi
- Department of Microbiology and Biotechnology, Faculty of Sciences, University of Debrecen, P.O. Box 63, H-4010 Debrecen, Hungary
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Current awareness on yeast. Yeast 2001; 18:1357-64. [PMID: 11571760 DOI: 10.1002/yea.690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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