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Zhou Z, Wang S, Fan P, Meng X, Cai X, Wang W, Ma L, Ma H, Su J. Borneol serves as an adjuvant agent to promote the cellular uptake of curcumin for enhancing its photodynamic fungicidal efficacy against Candida albicans. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2024; 253:112875. [PMID: 38430681 DOI: 10.1016/j.jphotobiol.2024.112875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 02/05/2024] [Accepted: 02/22/2024] [Indexed: 03/05/2024]
Abstract
Candida albicans (C. albicans), a major opportunistic pathogenic fungus, is known to cause superficial skin infections. Unfortunately, the misuse of antibiotics has led to the emergence of drug resistance in fungi. Antimicrobial photodynamic therapy (aPDT), a non-antibiotic alternative, has shown potential in treating drug-resistant fungal infections. Curcumin is a photodynamically active phytochemical whose photodynamic fungicidal efficacy is largely dependent on its intracellular accumulation. However, curcumin faces challenges in penetrating the cytoplasm due to its poor water solubility and the fungal cell wall. Borneol, another monoterpenoid phytochemical, is known for its ability to enhance drug absorption. In this study, we showed that borneol improved the cellular uptake of curcumin, thereby enhancing its photodynamic fungicidal efficacy against C. albicans. This effect was attributed to borneol's ability to increase cell permeability. Transcriptomic analysis further confirmed that borneol disrupted the normal structure and function of the C. albicans cell wall and membrane, resulting in dysregulated mRNA expression of related genes and ultimately increased cell permeability. As a result, the excessive accumulation of curcumin in C. albicans triggered the overproduction of intracellular ROS upon exposure to blue light. These excessive intracellular ROS disrupted various cellular structures, interfered with essential cellular processes, inhibited biofilm formation and reduced virulence. Remarkably, borneol was also found to enhance curcumin uptake by C. albicans within biofilms, further enhancing the anti-biofilm efficacy of curcumin-mediated aPDT (Cur-aPDT). In conclusion, the results of this study strongly support the potential of borneol as an adjuvant agent to Cur-aPDT in treating superficial cutaneous fungal infections.
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Affiliation(s)
- Zhenlong Zhou
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China; China-Singapore International Joint Research Institute, Guangzhou, China
| | - Shengli Wang
- Institute of Biomedical Transformation, School of Basic Medicine and Public Health, Jinan University, Guangzhou 510632, People's Republic of China
| | - Penghui Fan
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China; China-Singapore International Joint Research Institute, Guangzhou, China
| | - Xiaofeng Meng
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China; China-Singapore International Joint Research Institute, Guangzhou, China
| | - Xinyu Cai
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China
| | - Wen Wang
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China
| | - Lin Ma
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China; China-Singapore International Joint Research Institute, Guangzhou, China
| | - Hang Ma
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI 02881, USA
| | - Jianyu Su
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China; China-Singapore International Joint Research Institute, Guangzhou, China; Overseas Expertise Introduction Center for Discipline Innovation of Food Nutrition and Human Health (111 Center), Guangzhou, China.
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Lan Q, Li Y, Wang F, Li Z, Gao Y, Lu H, Wang Y, Zhao Z, Deng Z, He F, Wu J, Xu P. Deubiquitinase Ubp3 enhances the proteasomal degradation of key enzymes in sterol homeostasis. J Biol Chem 2021; 296:100348. [PMID: 33524398 PMCID: PMC8027567 DOI: 10.1016/j.jbc.2021.100348] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 12/22/2020] [Accepted: 01/25/2021] [Indexed: 12/27/2022] Open
Abstract
Sterol homeostasis is tightly controlled by molecules that are highly conserved from yeast to humans, the dysregulation of which plays critical roles in the development of antifungal resistance and various cardiovascular diseases. Previous studies have shown that sterol homeostasis is regulated by the ubiquitin–proteasome system. Two E3 ubiquitin ligases, Hrd1 and Doa10, are known to mediate the proteasomal degradation of 3-hydroxy-3-methylglutaryl-CoA reductase Hmg2 and squalene epoxidase Erg1 with accumulation of the toxic sterols in cells, but the deubiquitinases (DUBs) involved are unclear. Here, we screened for DUBs responsible for sterol homeostasis using yeast strains from a DUB-deletion library. The defective growth observed in ubp3-deleted (ubp3Δ) yeast upon fluconazole treatment suggests that lack of Ubp3 disrupts sterol homeostasis. Deep-coverage quantitative proteomics reveals that ergosterol biosynthesis is rerouted into a sterol pathway that generates toxic products in the absence of Ubp3. Further genetic and biochemical analysis indicated that Ubp3 enhances the proteasome's ability to degrade the ergosterol biosynthetic enzymes Erg1 and Erg3. The retardation of ergosterol enzyme degradation in the ubp3Δ strain resulted in the severe accumulation of the intermediate lanosterol and a branched toxic sterol, and ultimately disrupted sterol homeostasis and led to the fluconazole susceptibility. Our findings uncover a role for Ubp3 in sterol homeostasis and highlight its potential as a new antifungal target.
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Affiliation(s)
- Qiuyan Lan
- School of Basic Medical Science, Key Laboratory of Combinatorial Biosynthesis and Drug Discovery of Ministry of Education, School of Pharmaceutical Sciences, Wuhan University, Wuhan, China; State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Research Unit of Proteomics & Research and Development of New Drug of Chinese Academy of Medical Sciences, Beijing Institute of Lifeomics, Beijing, China
| | - Yanchang Li
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Research Unit of Proteomics & Research and Development of New Drug of Chinese Academy of Medical Sciences, Beijing Institute of Lifeomics, Beijing, China.
| | - Fuqiang Wang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Research Unit of Proteomics & Research and Development of New Drug of Chinese Academy of Medical Sciences, Beijing Institute of Lifeomics, Beijing, China
| | - Zhaodi Li
- Department of Cell Biology and Genetics, Molecular Medicine and Cancer Research Center, Chongqing Medical University, Chongqing, China
| | - Yuan Gao
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Research Unit of Proteomics & Research and Development of New Drug of Chinese Academy of Medical Sciences, Beijing Institute of Lifeomics, Beijing, China
| | - Hui Lu
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Research Unit of Proteomics & Research and Development of New Drug of Chinese Academy of Medical Sciences, Beijing Institute of Lifeomics, Beijing, China
| | - Yihao Wang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Research Unit of Proteomics & Research and Development of New Drug of Chinese Academy of Medical Sciences, Beijing Institute of Lifeomics, Beijing, China
| | - Zhenwen Zhao
- Beijing National Laboratory for Molecular Sciences, CAS Research/Education Center for Excellence in Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China
| | - Zixin Deng
- School of Basic Medical Science, Key Laboratory of Combinatorial Biosynthesis and Drug Discovery of Ministry of Education, School of Pharmaceutical Sciences, Wuhan University, Wuhan, China
| | - Fuchu He
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Research Unit of Proteomics & Research and Development of New Drug of Chinese Academy of Medical Sciences, Beijing Institute of Lifeomics, Beijing, China
| | - Junzhu Wu
- School of Basic Medical Science, Key Laboratory of Combinatorial Biosynthesis and Drug Discovery of Ministry of Education, School of Pharmaceutical Sciences, Wuhan University, Wuhan, China.
| | - Ping Xu
- School of Basic Medical Science, Key Laboratory of Combinatorial Biosynthesis and Drug Discovery of Ministry of Education, School of Pharmaceutical Sciences, Wuhan University, Wuhan, China; State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Research Unit of Proteomics & Research and Development of New Drug of Chinese Academy of Medical Sciences, Beijing Institute of Lifeomics, Beijing, China; Medical School of Guizhou University, Guiyang, China.
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3
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Ma H, Zhao X, Yang L, Su P, Fu P, Peng J, Yang N, Guo G. Antimicrobial Peptide AMP-17 Affects Candida albicans by Disrupting Its Cell Wall and Cell Membrane Integrity. Infect Drug Resist 2020; 13:2509-2520. [PMID: 32801789 PMCID: PMC7398874 DOI: 10.2147/idr.s250278] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 06/13/2020] [Indexed: 01/25/2023] Open
Abstract
Background Candida albicans is associated with high mortality among immunocompromised patients. Resistance to and toxic side effects of antifungal drugs require the development of alternative antifungal agents. AMP-17 is a novel antimicrobial peptide derived from Musca domestica that exerts excellent antifungal effects against the Candida species. In this article, we discuss the potential mechanism of AMP-17 against C. albicans from the perspective of affecting the latter's cell external structure. Methods Recombinant AMP-17 was prepared by prokaryotic expression system, and its anti-C. albicans activity was detected by microdilution method. Microscopy and scanning electron microscopy were used to examine morphological changes in C. albicans. Cell wall-specific staining method was used to detect the change of cell wall integrity of C. albicans after AMP-17 treatment. AMP-17-induced damage to the C. albicans cell membrane was analyzed by fluorescent probes and glycerol assay kit. The expression of genes related to fungal cell wall and cell-membrane synthesis was detected by qRT-PCR. Results Morphological observations showed that the growth of C. albicans was significantly inhibited in AMP-17-treated cells; the cells appeared aggregated and dissolved, with severe irregularities in shape. Furthermore, AMP-17 damaged the integrity of C. albicans cell walls. The cell wall integrity rate of AMP-17-treated cells was only 21.7% compared to untreated cells. Moreover, the change of membrane dynamics and permeability suggested that the cell membrane was disrupted by AMP-17 treatment. Genetic analysis showed that after AMP-17 treatment, the cell wall synthesis-related gene FKS2 of C. albicans was up-regulated 3.46-fold, while the cell membrane ergosterol synthesis-related genes ERG1, ERG5, ERG6, and MET6 were down-regulated 5.88-, 17.54-, 13.33-, and 7.14-fold, respectively. Conclusion AMP-17 treatment disrupted the cell wall integrity and membrane structure of C. albicans and is likely a novel therapeutic option for prevention and control of C. albicans infections.
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Affiliation(s)
- Huiling Ma
- Key and Characteristic Laboratory of Modern Pathogen Biology, School of Basic Medical Sciences, Guizhou Medical University, Guiyang 550025, People's Republic of China.,Department of Pathogen Biology and Immunology, School of Basic Medical Sciences, Sanquan College of Xinxiang Medical University, Xinxiang 453003, People's Republic of China
| | - Xinyu Zhao
- Key and Characteristic Laboratory of Modern Pathogen Biology, School of Basic Medical Sciences, Guizhou Medical University, Guiyang 550025, People's Republic of China
| | - Longbing Yang
- Key and Characteristic Laboratory of Modern Pathogen Biology, School of Basic Medical Sciences, Guizhou Medical University, Guiyang 550025, People's Republic of China
| | - Peipei Su
- Key and Characteristic Laboratory of Modern Pathogen Biology, School of Basic Medical Sciences, Guizhou Medical University, Guiyang 550025, People's Republic of China
| | - Ping Fu
- Key and Characteristic Laboratory of Modern Pathogen Biology, School of Basic Medical Sciences, Guizhou Medical University, Guiyang 550025, People's Republic of China.,Key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education, Guizhou Medical University, Guiyang 550025, People's Republic of China
| | - Jian Peng
- Key and Characteristic Laboratory of Modern Pathogen Biology, School of Basic Medical Sciences, Guizhou Medical University, Guiyang 550025, People's Republic of China.,Key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education, Guizhou Medical University, Guiyang 550025, People's Republic of China
| | - Na Yang
- School of Food Science, Guizhou Medical University, Guiyang 550025, People's Republic of China
| | - Guo Guo
- Key and Characteristic Laboratory of Modern Pathogen Biology, School of Basic Medical Sciences, Guizhou Medical University, Guiyang 550025, People's Republic of China.,Key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education, Guizhou Medical University, Guiyang 550025, People's Republic of China.,School of Food Science, Guizhou Medical University, Guiyang 550025, People's Republic of China
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Affiliation(s)
- J. D. Weete
- Department of Botany & Microbiology, Alabama Agricultural Experiment Station, Auburn University, Alabama 36849 USA
| | - S. R. Gandhi
- Department of Botany & Microbiology, Alabama Agricultural Experiment Station, Auburn University, Alabama 36849 USA
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5
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Critical steps in carbon metabolism affecting lipid accumulation and their regulation in oleaginous microorganisms. Appl Microbiol Biotechnol 2018; 102:2509-2523. [DOI: 10.1007/s00253-018-8813-z] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 01/23/2018] [Accepted: 01/24/2018] [Indexed: 12/11/2022]
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6
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Calonne M, Sahraoui ALH, Campagnac E, Debiane D, Laruelle F, Grandmougin-Ferjani A, Fontaine J. Propiconazole inhibits the sterol 14α-demethylase in Glomus irregulare like in phytopathogenic fungi. CHEMOSPHERE 2012; 87:376-83. [PMID: 22239944 DOI: 10.1016/j.chemosphere.2011.12.027] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Revised: 12/08/2011] [Accepted: 12/09/2011] [Indexed: 05/31/2023]
Abstract
The increasing concentrations impact (0.02, 0.2 and 2 mg L(-1)) of a Sterol Biosynthesis Inhibitor (SBI) fungicide, propiconazole, was evaluated on development and sterol metabolism of two non-target organisms: mycorrhizal or non-mycorrhizal transformed chicory roots and the arbuscular mycorrhizal fungus (AMF) Glomus irregulare using monoxenic cultures. In this work, we provide the first evidence of a direct impact of propiconazole on the AMF by disturbing its sterol metabolism. A significant decrease in end-products sterols contents (24-methylcholesterol and in 24-ethylcholesterol) was observed concomitantly to a 24-methylenedihydrolanosterol accumulation indicating the inhibition of a key enzyme in sterol biosynthesis pathway, the sterol 14α-demethylase like in phytopathogenic fungi. A decrease in end-product sterol contents in propiconazole-treated roots was also observed suggesting a slowing down of the sterol metabolism in plant. Taken together, our findings suggest that the inhibition of the both AM symbiotic partners development by propiconazole results from their sterol metabolism alterations.
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Affiliation(s)
- Maryline Calonne
- Univ Lille Nord de France, F-59000 Lille Université du Littoral Côte d'Opale, Unité de Chimie Environnementale et Interactions sur le Vivant, F-62228 Calais, France
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7
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Affiliation(s)
- W David Nes
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409, USA.
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8
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Mysyakina IS, Funtikova NS. Sporangiospore lipids of the mycelial fungus Mucor ramannianus incapable of dimorphic growth. Microbiology (Reading) 2007. [DOI: 10.1134/s002626170702004x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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9
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Stehmann C, Kapteyn JC, De Waard MA. Development of a cell-free assay fromBotrytis cinereaas a biochemical screen for sterol biosynthesis inhibitors. ACTA ACUST UNITED AC 2006. [DOI: 10.1002/ps.2780400102] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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10
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Köller W. Isomers of sterol synthesis inhibitors: Fungicidal effects and plant growth regulator activities. ACTA ACUST UNITED AC 2006. [DOI: 10.1002/ps.2780180206] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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11
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Arnold A, Betto E, Farina G, Formigoni A, Galli R, Merlini L. Synthesis and fungicidal activity of a series of 1,1-disubstituted-but-3-yn-1-ols. ACTA ACUST UNITED AC 2006. [DOI: 10.1002/ps.2780150313] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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12
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Giner JL, Zhao H, Amit Z, Kaneshiro ES. Sterol composition of Pneumocystis jirovecii with blocked 14alpha-demethylase activity. J Eukaryot Microbiol 2005; 51:634-43. [PMID: 15666720 DOI: 10.1111/j.1550-7408.2004.tb00597.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Several drugs that interact with membrane sterols or inhibit their syntheses are effective in clearing a number of fungal infections. The AIDS-associated lung infection caused by Pneumocystis jirovecii is not cleared by many of these therapies. Pneumocystis normally synthesizes distinct C28 and C29 24-alkylsterols, but ergosterol, the major fungal sterol, is not among them. Two distinct sterol compositional phenotypes were previously observed in P. jirovecii. One was characterized by delta7 C28 and C29 24-alkylsterols with only low proportions of higher molecular mass components. In contrast, the other type was dominated by high C31 and C32 24-alkylsterols, especially pneumocysterol. In the present study, 28 molecular species were elucidated by nuclear magnetic resonance analysis of a human lung specimen containing P. jirovecii representing the latter sterol profile phenotype. Fifteen of the 28 had the methyl group at C-14 of the sterol nucleus and these represented 96% of the total sterol mass in the specimen (excluding cholesterol). These results strongly suggest that sterol 14alpha-demethylase was blocked in these organisms. Twenty-four of the 28 were 24-alkylsterols, indicating that methylation of the C-24 position of the sterol side chain by S-adenosyl-L-methionine:sterol C-24 methyl transferase was fully functional.
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Affiliation(s)
- José-Luis Giner
- Department of Chemistry, State University of New York-ESF, Syracuse, NY 13210, USA.
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13
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Garandeau PJM, Chollet JF, Miginiac L. Synthèse de (3-aminopropyl)arylsilanes, comportant un ou deux motifs hétérocycliques, fongicides potentials. Helv Chim Acta 2004. [DOI: 10.1002/hlca.19970800308] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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14
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König KH. Fortschritte im chemischen Pflanzenschutz. Teil I: Neue Erkenntnisse erfordern neue Zielsetzungen am Beispiel der Herbizide. CHEM UNSERER ZEIT 2004. [DOI: 10.1002/ciuz.19900240506] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Turk M, Méjanelle L, Sentjurc M, Grimalt JO, Gunde-Cimerman N, Plemenitas A. Salt-induced changes in lipid composition and membrane fluidity of halophilic yeast-like melanized fungi. Extremophiles 2003; 8:53-61. [PMID: 15064990 DOI: 10.1007/s00792-003-0360-5] [Citation(s) in RCA: 124] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2002] [Accepted: 09/12/2003] [Indexed: 11/28/2022]
Abstract
The halophilic melanized yeast-like fungi Hortaea werneckii, Phaeotheca triangularis, and the halotolerant Aureobasidium pullulans, isolated from salterns as their natural environment, were grown at different NaCl concentrations and their membrane lipid composition and fluidity were examined. Among sterols, besides ergosterol, which was the predominant one, 23 additional sterols were identified. Their total content did not change consistently or significantly in response to raised NaCl concentrations in studied melanized fungi. The major phospholipid classes were phosphatidylcholine and phosphatidylethanolamine, followed by anionic phospholipids. The most abundant fatty acids in phospholipids contained C16 and C18 chain lengths with a high percentage of C18:2Delta9,12. Salt stress caused an increase in the fatty acid unsaturation in the halophilic H. werneckii and halotolerant A. pullulans but a slight decrease in halophilic P. triangularis. All the halophilic fungi maintained their sterol-to-phospholipid ratio at a significantly lower level than did the salt-sensitive Saccharomyces cerevisiae and halotolerant A. pullulans. Electron paramagnetic resonance (EPR) spectroscopy measurements showed that the membranes of all halophilic fungi were more fluid than those of the halotolerant A. pullulans and salt-sensitive S. cerevisiae, which is in good agreement with the lipid composition observed in this study.
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Affiliation(s)
- Martina Turk
- Institute of Biochemistry, Medical Faculty, University of Ljubljana, Vrazov trg 2, 1000, Ljubljana, Slovenia
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Feio SS, Franca S, Silva AM, Gigante B, Roseiro JC, Marcelo Curto MJ. Antimicrobial activity of methyl cis-7-oxo deisopropyldehydroabietate on Botrytis cinerea and Lophodermium seditiosum: ultrastructural observations by transmission electron microscopy. J Appl Microbiol 2003; 93:765-71. [PMID: 12392521 DOI: 10.1046/j.1365-2672.2002.01744.x] [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] [Indexed: 11/20/2022]
Abstract
AIMS To study the antifungal activity of methyl cis-7-oxo-deisopropyldehydroabietate (MCOD) against phytopathogenic fungi, Botrytis cinerea and Lophodermium seditiousm. The effect of the compound was studied by transmission electron microscopy (TEM) and the composition of sterols on both treated and untreated cultures was determined. METHODS AND RESULTS MCOD was tested at concentrations in the range 0.003-0.5% by the agar plate dilution method. The radial growth of the colonies treated with MCOD was measured against colonies from untreated cultures. The radial growth of colonies of both fungi and the spore germination of B. cinerea were partially or completely inhibited. Fragments of active growing colonies treated and untreated with MCOD were submitted to the conventional procedure for ultrastructural observation by TEM. Observations by TEM on colonies of B. cinerea and L. seditiosum under 0.1% MCOD revealed several autophagic-like vacuoles, morphological alterations on lomasome and lipid accumulations in the apical zone of hyphae of both fungi. Observations on spore germination of B. cinerea revealed the presence of strongly stained lipid accumulations retained by vacuoles at the cell periphery of young hyphae. The sterol composition of B. cinerea and L. seditiosum was determined on MCOD treated and untreated cultures by gas-chromatography/mass-spectrometry (GC-MS) with molecular ions and fragmentation patterns characteristics of ergosterol (M+396) and dihydroergosterol (M+398) in both fungi. CONCLUSIONS The morphological alterations are consistent with an unspecific mode of action of MCOD causing inhibition of normal growth or damaging the fungi cells. TEM observations suggest a mechanism of resistance based on the retention of MCOD by the lipid accumulation. SIGNIFICANCE AND IMPACT OF THE STUDY The results obtained in the present work afforded a better understanding of the mode of action of a resin acid derivative on phytopathogenic fungi. The inhibition growth of both fungi by MCOD demonstrates the antifungal activity of this compound and the interest on further in vivo studies, in order to evaluate its potential as a benign alternative to conventional fungicides.
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Affiliation(s)
- S Savluchinske Feio
- Instituto Nacional de Engenharia e Tecnologia Industrial, Estrada ao Paço do Lumiar, 1699-038, Lisboa, Portugal.
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Barrero AF, Oltra JE, Robinson J, Burke PV, Jiménez D, Oliver E. Sterols in erg mutants of Phycomyces: metabolic pathways and physiological effects. Steroids 2002; 67:403-9. [PMID: 11958798 DOI: 10.1016/s0039-128x(01)00195-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Phycomyces is a fungal producer of beta-carotene and other beneficial metabolites. Several erg mutants of Phycomyces, originally selected to study the effects of membrane alteration on physiological responses, have now been used to gain information about sterol biosynthesis in filamentous fungi. One mutant, H23, and its progeny were found to be blocked at episterol C-5 dehydrogenase and did not produce ergosterol or any other sterol with a conjugated Delta(5,7) diene system. This mutant showed abnormal phototropism, which was correlated with the altered sterol composition. Another mutant, H25, seems to be a regulatory mutant. All analyzed mutants synthesized ergosta-7,22,24(28)-trien-3beta-ol, demonstrating for the first time that the sterol C-22 dehydrogenase of Phycomyces is capable of recognizing sterols with a 24(28) unsaturated side chain. New evidence regarding the biogenesis of neoergosterol and phycomysterols, the potential sparking function of cholesterol, as well as the regulation of sterol biosynthesis in this fungus is also reported. Given these results, a pathway for sterol biosynthesis in Phycomyces is proposed.
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Affiliation(s)
- Alejandro F Barrero
- Departamento de Química Orgánica, Instituto de Biotecnología, Facultad de Ciencias, Granada, Spain.
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18
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Debieu D, Bach J, Hugon M, Malosse C, Leroux P. The hydroxyanilide fenhexamid, a new sterol biosynthesis inhibitor fungicide efficient against the plant pathogenic fungus Botryotinia fuckeliana (Botrytis cinerea). PEST MANAGEMENT SCIENCE 2001; 57:1060-1067. [PMID: 11721524 DOI: 10.1002/ps.394] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Fenhexamid, a recently developed botryticide, is shown here to inhibit sterol biosynthesis. When the fungus Botryotinia fuckeliana was grown in the presence of fenhexamid, the ergosterol content was reduced, and three 3-keto compounds, 4 alpha-methylfecosterone, fecosterone and episterone, accumulated, suggesting an inhibition of the 3-keto reductase involved in C-4 demethylation. Thus, fenhexamid belongs to a new, promising class of sterol biosynthesis inhibitors not previously used in agriculture or in medicine.
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Affiliation(s)
- D Debieu
- INRA, Unité de Phytopharmacie et Médiateurs Chimiques, 78026 Versailles, France.
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Lamb DC, Warrilow AG, Venkateswarlu K, Kelly DE, Kelly SL. Activities and kinetic mechanisms of native and soluble NADPH-cytochrome P450 reductase. Biochem Biophys Res Commun 2001; 286:48-54. [PMID: 11485306 DOI: 10.1006/bbrc.2001.5338] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Native yeast NADPH-cytochrome P450 oxidoreductase (CPR; EC 1.6.2.4) and a soluble derivative lacking 33 amino acids of the NH(2)-terminus have been overexpressed as recombinant proteins in Escherichia coli. The presence of a hexahistidine sequence at the N-terminus allowed protein purification in a single step using nickel-chelating affinity chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis confirmed the predicted molecular weights of the proteins and indicated a purity of >95%. Protein functionality was demonstrated by cytochrome c reduction and reconstitution of CYP61-mediated sterol Delta(22)-desaturation. Steady-state kinetics of cytochrome c reductase activity revealed a random Bi-Bi mechanism with NADPH donating electrons directly to CPR to produce a reduced intermediary form of the enzyme. The kinetic mechanism studies showed no difference between the two yeast CPRs in mechanism or after reconstitution with CYP61-mediated 22-desaturation, confirming that the retention of the NH(2)-terminable membrane anchor is functionally dispensable.
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Affiliation(s)
- D C Lamb
- Institute of Biological Sciences, University of Wales-Aberystwyth, Aberystwyth SY23 3DA, Wales, United Kingdom
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Méjanelle L, Lòpez JF, Gunde-Cimerman N, Grimalt JO. Ergosterol biosynthesis in novel melanized fungi from hypersaline environments. J Lipid Res 2001. [DOI: 10.1016/s0022-2275(20)31658-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Chung SK, Lee KW, Kang HI, Yamashita C, Kudo M, Yoshida Y. Design and synthesis of potential inhibitors of the ergosterol biosynthesis as antifungal agents. Bioorg Med Chem 2000; 8:2475-86. [PMID: 11058043 DOI: 10.1016/s0968-0896(00)00177-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A series of azolylmethyloxolane derivatives with modified sterol side-chain structures, designed as potential dual functional inhibitors of cytochrome P450 14alpha-demethylase (14DM) and delta24-sterol methyltransferase (24-SMT) based on the common characteristic features of 24-aminosterols and azole antifungal agents, were synthesized and evaluated for their antifungal activities and inhibitory activities of 14DM and 24-SMT. Among these compounds, imidazolylmethyloxolane derivatives 28a and 28b showed potent in vitro antifungal activities comparable to those of itraconazole. However, the in vitro bioactivities have not been linearly translated into in vivo protection data for some unknown reasons.
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Affiliation(s)
- S K Chung
- Department of Chemistry, Pohang University of Science & Technology, South Korea.
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Muchembled J, Sahraoui ALH, Grandmougin-Ferjani A, Sancholle M. Changes in sterol composition with ontogeny of Blumeria graminis conidia. ACTA ACUST UNITED AC 2000. [DOI: 10.1139/b00-106] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The total sterol composition of conidia of the obligate plant pathogen Blumeria (= Erysiphe) graminis f.sp. tritici has been analysed as a function of their ontogeny during sporulation. Two main classes of sterols were characterized: 24-ethylsterols (24-ethylcholesta-5,22-dienol, 24-ethylcholesterol, and Δ5-avenasterol) and 24-methylsterols (24-methylenecholesterol and episterol). Our results show that sterol composition is greatly modified during ontogeny of B. graminis conidia both at the qualitative and quantitative levels. In particular, 24-methylsterols, e.g., 24-methylenecholesterol and episterol, are the major sterols in old conidia whereas 24-ethylsterols, e.g., 24-ethylcholesta-5,22-dienol, 24-ethylcholesterol, and Δ5-avenasterol, are the main sterols in young conidia.Key words: Erysiphe, wheat powdery mildew, sterols, ontogeny.
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24
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Kaneshiro ES, Wyder MA. C27 to C32 sterols found in Pneumocystis, an opportunistic pathogen of immunocompromised mammals. Lipids 2000; 35:317-24. [PMID: 10783009 DOI: 10.1007/s11745-000-0528-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Pneumocystis carinii is the paradigm of opportunistic infections in immunocompromised mammals. Prior to the acquired immunodeficiency syndrome (AIDS) pandemic and the use of immunosuppressive therapy in organ transplant and cancer patients, P. carinii was regarded as a curiosity, rarely observed clinically. Interest in this organism exploded when it was identified as the agent of P. carinii pneumonia (PcP), the direct cause of death among many AIDS patients. Aggressive prophylaxis has decreased the number of acute PcP cases, but it remains among the most prevalent opportunistic infections found within this patient population. The taxonomic assignment of P. carinii has long been argued; molecular genetics data now demonstrate that it is a fungus. Several antimycotic drugs are targeted against ergosterol or its biosynthesis, but these are not as effective against PcP as they are against other fungal infections. This can now be explained in part by the identification of the sterols of P. carinii. The organism lacks ergosterol but contains distinct C28 and C29 delta7 24-alkylsterols. Also, 24-methylenelanost-8-en-3beta-ol (C31) and pneumocysterol, (24Z)-ethylidenelanost-8-en-3beta-ol (C32) were recently identified in organisms infecting humans. Together, the delta7 24-alkylsterols and pneumocysterol are regarded as signature lipids of the pathogen that can be useful for the diagnosis of PcP, since no other lung pathogen is known to contain them. Cholesterol (C27), the dominant sterol component in P. carinii, is probably totally scavenged from the host. De novo synthesis of sterols has been demonstrated by the presence of lovastatin-sensitive 3-hydroxy-3-methylglutaryl-CoA reductase activity, the incorporation of radiolabeled mevalonate and squalene into P. carinii sterols, and the reduction in cellular ATP in cells treated with inhibitors of enzymes in sterol biosynthesis.
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Affiliation(s)
- E S Kaneshiro
- Department of Biological Sciences, University of Cincinnati, Ohio 45221-0006, USA.
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25
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Stanetty P, Kremslehner M, Mihovilovic MD. A novel synthetic approach towards the AB-ring system of 9-azasteroids. Tetrahedron Lett 2000. [DOI: 10.1016/s0040-4039(00)00020-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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26
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Debieu D, Bach J, Lasseron A, Malosse C, Leroux P. Effects of sterol biosynthesis inhibitor fungicides in the phytopathogenic fungus,Nectria haematococca:ergosterol depletion versus precursor or abnormal sterol accumulation as the mechanism of fungitoxicity. ACTA ACUST UNITED AC 1999. [DOI: 10.1002/(sici)1096-9063(1998100)54:2<157::aid-ps799>3.0.co;2-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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27
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Barrero AF, Oltra JE, Poyatos JA, Jiménez D, Oliver E. Phycomysterols and other sterols from the fungus Phycomyces blakesleeanus. JOURNAL OF NATURAL PRODUCTS 1998; 61:1491-1496. [PMID: 9868149 DOI: 10.1021/np980199h] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
In the search for novel bioactive products from filamentous fungi, sterols and triterpenoids found in Phycomyces blakesleeanus were analyzed using semipreparative HPLC, GC-MS, and NMR techniques. Structures proposed for the three new compounds identified, phycomysterol A (1), phycomysterol B (2), and neoergosterol (3), were confirmed by chemical synthesis. Phycomysterols possess a new natural 19-norergostane skeleton with an aromatic B ring. Phycomysterol A showed anti-HIV activity.
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Affiliation(s)
- A F Barrero
- Departamento de Química Orgánica, Instituto de Biotecnología, Facultad de Ciencias, Universidad de Granada, Campus Fuentenueva s/n, 18071 Granada,
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28
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Chung SK, Ryoo CH, Yang HW, Shim JY, Kang MG, Lee KW, Kang HI. Synthesis and bioactivities of steroid derivatives as antifungal agents. Tetrahedron 1998. [DOI: 10.1016/s0040-4020(98)01000-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Leber R, Landl K, Zinser E, Ahorn H, Spök A, Kohlwein SD, Turnowsky F, Daum G. Dual localization of squalene epoxidase, Erg1p, in yeast reflects a relationship between the endoplasmic reticulum and lipid particles. Mol Biol Cell 1998; 9:375-86. [PMID: 9450962 PMCID: PMC25265 DOI: 10.1091/mbc.9.2.375] [Citation(s) in RCA: 160] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Squalene epoxidase, encoded by the ERG1 gene in yeast, is a key enzyme of sterol biosynthesis. Analysis of subcellular fractions revealed that squalene epoxidase was present in the microsomal fraction (30,000 x g) and also cofractionated with lipid particles. A dual localization of Erg1p was confirmed by immunofluorescence microscopy. On the basis of the distribution of marker proteins, 62% of cellular Erg1p could be assigned to the endoplasmic reticulum and 38% to lipid particles in late logarithmic-phase cells. In contrast, sterol Delta24-methyltransferase (Erg6p), an enzyme catalyzing a late step in sterol biosynthesis, was found mainly in lipid particles cofractionating with triacylglycerols and steryl esters. The relative distribution of Erg1p between the endoplasmic reticulum and lipid particles changes during growth. Squalene epoxidase (Erg1p) was absent in an erg1 disruptant strain and was induced fivefold in lipid particles and in the endoplasmic reticulum when the ERG1 gene was overexpressed from a multicopy plasmid. The amount of squalene epoxidase in both compartments was also induced approximately fivefold by treatment of yeast cells with terbinafine, an inhibitor of the fungal squalene epoxidase. In contrast to the distribution of the protein, enzymatic activity of squalene epoxidase was only detectable in the endoplasmic reticulum but was absent from isolated lipid particles. When lipid particles of the wild-type strain and microsomes of an erg1 disruptant were mixed, squalene epoxidase activity was partially restored. These findings suggest that factor(s) present in the endoplasmic reticulum are required for squalene epoxidase activity. Close contact between lipid particles and endoplasmic reticulum may be necessary for a concerted action of these two compartments in sterol biosynthesis.
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Affiliation(s)
- R Leber
- Institut für Biochemie und Lebensmittelchemie and SFB Biomembrane Research Center, Technische Universität Graz, 1121 Vienna, Austria
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Abstract
The sterol composition of 42 fungal species representing six of the eight orders of the Zygomycota was determined using gas-liquid chromatography-mass spectrometry to assess whether the distribution of major sterols in this phylum has taxonomic or phylogenetic relevance. Ergosterol, 22-dihydroergosterol, 24-methyl cholesterol, cholesterol, and desmosterol were detected as the major sterols among the species studied. Ergosterol was the major sterol of the Dimargaritales, Zoopagales, and 13 of the 14 Mucorales families included in this study. Desmosterol appeared to be the characteristic sterol of the Mortierellaceae (Mucorales), 24-Methyl cholesterol was the major sterol of the Entomophthorales genera Entomophthora, Conidiobolus and Basidiobolus, but cholesterol was the sole sterol detected in Delacroixia coronatus. The Kickxellales species analyzed in this study were characterized by 22-dihydroergosterol as the major sterol. These results suggest that certain orders of the Zygomycota may be distinguished on the basis of major sterol. Also, if sterol structure has phylogenetic implications, then orders might be arranged in the order Kickxellales (C28 delta 5,7)-->Dimargaritales, Zoopagales and Mucorales (C28 delta 5,7,22) on the basis of evolution of the predominant and presumably most competent sterol, ergosterol. Although the Entomophthorales would be expected to be more primitive than the above orders based on the predominance of C28 delta 5, it is not apparent from these data that members of the Zygomycota with ergosterol or its precursors as major sterols evolved from this taxon or the Chytridiomycota.
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Affiliation(s)
- J D Weete
- Department of Botany and Microbiology, Alabama Agricultural Experiment Station, Auburn University 36849, USA
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Bach TJ, Benveniste P. Cloning of cDNAs or genes encoding enzymes of sterol biosynthesis from plants and other eukaryotes: heterologous expression and complementation analysis of mutations for functional characterization. Prog Lipid Res 1997; 36:197-226. [PMID: 9624427 DOI: 10.1016/s0163-7827(97)00009-x] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- T J Bach
- Institut de Biologie Moléculaire des Plantes (C.N.R.S., UPR 0406), Université Louis Pasteur, Strasbourg, France
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Goldstein AS, Frye LL. Synthesis and bioevaluation of delta 7-5-desaturase inhibitors, an enzyme late in the biosynthesis of the fungal sterol ergosterol. J Med Chem 1996; 39:5092-9. [PMID: 8978840 DOI: 10.1021/jm9605851] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Ergosterol, the predominant sterol of fungi, is postulated to have many cellular functions which include a bulk membrane role and a regulatory role. Studies with sterol auxotrophs show that, even in the presence of sterols which can fulfill the bulk membrane requirements, a small concentration of ergosterol is absolutely necessary for growth. The delta 5-double bond appears to be required for the regulatory role of ergosterol; therefore, development of inhibitors of the enzyme that introduce this double bond, delta 7-sterol 5-desaturase (5-desaturase), may lead to effective antifungal agents. Within is the first reported synthesis of inhibitors of fungal 5-desaturase and the development of an in vitro tritium efficacy radioassay. The inhibitors were of the general structure 7,22(E)-ergostadien-3 beta-ol with alpha-face heteroatom substituents in the vicinity of C-5. They exhibited IC50 values of 47-149 microM.
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Affiliation(s)
- A S Goldstein
- Cogswell Lab, Renessalear Polytechnic Institute, Troy, New York 12180, USA
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Venkateswarlu K, Kelly SL. Biochemical characterisation of ketoconazole inhibitory action on Aspergillus fumigatus. FEMS IMMUNOLOGY AND MEDICAL MICROBIOLOGY 1996; 16:11-20. [PMID: 8954348 DOI: 10.1111/j.1574-695x.1996.tb00106.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The effect of ketoconazole on growth, sterol composition, in vitro sterol biosynthesis and P450-CO complex formation and its interaction with microsomal P450 was determined. On solid medium and in liquid medium ketoconazole inhibited Aspergillus fumigatus growth completely at 5 x 10(-5) M and 50% of the growth at 1.3 x 10(-5) M and 2.1 x 10(-5) M respectively. A close relationship between accumulation of 14 alpha-methyl sterols (eburicol, obtusifoliol and 14 alpha-methyl fecosterol) and depletion of ergosterol with growth arrest was observed in ketoconazole treated cultures. The half inhibitory concentration for in vitro ergosterol biosynthesis and half saturating concentration for type II binding spectrum of ketoconazole were calculated as 73.8 +/- 6.3 nM and 0.13 +/- 0.04 microM respectively. CO displacement studies revealed inhibition of CO-P450 complex formation by ketoconazole.
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Affiliation(s)
- K Venkateswarlu
- Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, University of Sheffield, UK
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35
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Joseph-Horne T, Hollomon D, Manning N, Kelly SL. Investigation of the Sterol Composition and Azole Resistance in Field Isolates of Septoria tritici. Appl Environ Microbiol 1996; 62:184-90. [PMID: 16535210 PMCID: PMC1388752 DOI: 10.1128/aem.62.1.184-190.1996] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We report here a biochemical study of resistance to azole antifungal agents in a field isolate (S-27) of a fungal phytopathogen. Isolates of Septoria tritici were compared in vitro, and their responses reflected that observed in the field, with S-27 exhibiting resistance relative to RL2. In untreated cultures, both RL2 and S-27 contained isomers of ergosterol and ergosta-5,7-dienol, although in differing concentrations. Under azole treatment, this phytopathogen exhibited a response similar to that of other pathogenic fungi, with a reduction in desmethyl sterols and an accumulation of 14(alpha)-methyl sterols, indicative of inhibition of the P450-mediating sterol 14(alpha)-demethylase. Growth arrest was attributed to the reduction of ergosterol combined with an accumulation of nonutilizable sterols. Strain S-27 exhibited an azole-resistant phenotype which was correlated with decreased cellular content of azole.
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36
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Lamb DC, Corran A, Baldwin BC, Kwon-Chung J, Kelly SL. Resistant P45051A1 activity in azole antifungal tolerant Cryptococcus neoformans from AIDS patients. FEBS Lett 1995; 368:326-30. [PMID: 7628631 DOI: 10.1016/0014-5793(95)00684-2] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Azole antifungal compounds are important in the treatment of Cryptococcosis, a major cause of mortality in AIDS patients. The target of the azole drugs is P450 mediated sterol 14 alpha-demethylase. We have investigated the P450 system of Cryptococcus neoformans with respect to azole tolerance observed in clinical isolates which were obtained following the failure of fluconazole therapy. The clinical failure was correlated with in vitro tolerance of azole antifungal when compared to wild-type strains. The microsomal P450 system was typical of yeast and fungi and fluconazole tolerance was not associated with defective sterol biosynthesis. The strains had slightly elevated P450 content and slightly reduced azole levels in the cells, but a clear cause for resistance was the increased level of drug needed to inhibit the sterol 14 alpha-demethylase in vitro.
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Affiliation(s)
- D C Lamb
- Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, Sheffield University, UK
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Kelly SL, Lamb DC, Taylor M, Corran AJ, Baldwin BC, Powderly WG. Resistance to amphotericin B associated with defective sterol delta 8-->7 isomerase in a Cryptococcus neoformans strain from an AIDS patient. FEMS Microbiol Lett 1994; 122:39-42. [PMID: 7958776 DOI: 10.1111/j.1574-6968.1994.tb07140.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Two Cryptococcus neoformans strains isolated from an AIDS patient were investigated, a pretreatment isolate (CN1) and a second isolate (CN3) following failure of fluconazole and amphotericin B treatment. No difference in fluconazole sensitivity, but relative resistance to amphotericin B was observed for CN3. The sterol composition of CN3 indicated a defect in sterol delta 8-->7 isomerase in this strain and depletion of ergosterol, the major sterol of the CN1.
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Affiliation(s)
- S L Kelly
- Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, Sheffield University, UK
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Kirsch DR, DiDomenico BJ. Mechanism-based screening for the discovery of novel antifungals. BIOTECHNOLOGY (READING, MASS.) 1994; 26:177-221. [PMID: 7749303 DOI: 10.1016/b978-0-7506-9003-4.50012-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- D R Kirsch
- Agricultural Research Division, American Cyanamid, Princeton, New Jersey, USA
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Affiliation(s)
- E I Mercer
- Department of Biochemistry, University of Wales, Aberystwyth, Dyfed, U.K
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40
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Butty P, Gorenflot A, Mallié M, Bastide JM. Low voltage scanning electron microscopy study of naftifine activity on Microsporum canis. Mycoses 1992; 35:335-42. [PMID: 1302809 DOI: 10.1111/j.1439-0507.1992.tb00891.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Scanning electron microscopy (SEM) is at present considered a good way to observe the morphological alterations induced by an antifungal on pathogenic fungi. Owing to its high precision, low voltage scanning electron microscopy (LVSEM) improves the quality of observations. The Microsporum canis morphology alterations induced by naftifine at a concentration of 0.9 microgram ml-1 (10 times the minimum inhibitory concentration (MIC) for 7 days were studied in LVSEM. The young lateral ramifications and the aborted buds take on a granulous aspect. These granulations can be localized as brassard shapes around hyphae. The mycelial filaments often appear irregularly swollen with bulbous tips. Macroconidia are selectively covered with a microfibrillar network. In addition, LVSEM on control samples reveals pavimentous angular structures on the macroconidial surface and fine granulations on the filament surface of M. canis unknown until now. A cytological study with transmission electron microscopy (TEM) of filaments altered by naftifine permitted us to observe the disorganization of cell wall fibrillar structure, an excessive plasma membrane undulation and an intracytoplasmic accumulation of large vesicles with probably lipidic contents.
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Affiliation(s)
- P Butty
- Laboratoire d'Immunologic et Parasitologie, Faculté de Pharmacie, Montpellier, France
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41
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Lorenz RT, Parks LW. Cloning, sequencing, and disruption of the gene encoding sterol C-14 reductase in Saccharomyces cerevisiae. DNA Cell Biol 1992; 11:685-92. [PMID: 1418625 DOI: 10.1089/dna.1992.11.685] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
A sterol C-14 reductase (erg24-1) mutant of Saccharomyces cerevisiae was selected in a fen1, fen2, suppressor background on the basis of nystatin resistance and ignosterol (ergosta-8,14-dienol) production. The erg24-1 allele segregated genetically as a single, recessive gene. The wild-type ERG24 gene was cloned by complementation onto a 12-kb fragment from a yeast genomic library, and subsequently subcloned onto a 2.4-kb fragment. This was sequenced and found to contain an open reading frame of 1,314 bp, predicting a polypeptide of 438 amino acids (M(r) 50,612). A 1,088-bp internal region of the ERG24 gene was excised, replaced with a LEU2 gene, and integrated into the chromosome of the parental strain, FP13D (fen1, fen2) by gene replacement. The ERG24 null mutant produced ergosta-8,14-dienol as the major sterol, indicating that the delta 8-7 isomerase, delta 5-desaturase and the delta 22-desaturase were inactive on sterols with the C14 = 15 double bond.
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Affiliation(s)
- R T Lorenz
- Department of Microbiology, North Carolina State University, Raleigh 27695-7615
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Marcireau C, Guyonnet D, Karst F. Construction and growth properties of a yeast strain defective in sterol 14-reductase. Curr Genet 1992; 22:267-72. [PMID: 1394506 DOI: 10.1007/bf00317919] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
We have transformed Saccharomyces cerevisiae with a genomic library contained in the replicative vector pFL44. The resulting transformants were screened for resistance to fenpropidin, a specific inhibitor of sterol 14-reductase. A plasmid was isolated that transformed yeast both to resistance to fenpropidin and to an increased specific activity of sterol 14-reductase. Sterol analysis of transformed cells grown in the presence of increasing concentrations of the inhibitor confirmed that resistance was a consequence of over-production of sterol 14-reductase. By chromosomal gene disruption, we have, for the first time, constructed yeast strains defective in sterol 14-reductase. As expected, since yeast in unable to take up sterols in aerobiosis, the disrupted strains do not grow in the presence of oxygen, even if exogenous sterols are supplied. However, disrupted cells grow in anaerobiosis with exogenous oleic acid and ergosterol supplements. They also grow in aerobiosis if they bear an additional mutation allowing sterol uptake. In this last growth condition the cells require a "sparking" ergosterol supplementation (25 nM) and accumulate ignosterol (ergosta-8,14-dienol) as the end-product of the sterol pathway. These results reveal that ignosterol is not obviously toxic to yeast membranes and strongly suggest that the molecular basis of the antifungal-activity morpholine and piperidine is directly related to the specific inhibition of ergosterol formation.
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Affiliation(s)
- C Marcireau
- Laboratoire de Biochimie et Génétique des Microorganismes, Université de Poitiers, France
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43
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Huxley-Tencer A, Francotte E, Bladocha-Moreau M. 1(R)-(2,6-cis-dimethylmorpholino)- 3(S)-(p-tert-butylphenyl)cyclopentane: A representative of a novel, potent class of bio-rationally designed fungicides. ACTA ACUST UNITED AC 1992. [DOI: 10.1002/ps.2780340110] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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44
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Abstract
The mechanism of each of the reactions in the post-squalene segment of the fungal and higher plant sterol biosynthetic pathway is outlined. The inhibitors of the enzymes catalyzing the reactions are described and how inhibition is brought about is explained in the areas where it is known.
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Affiliation(s)
- E I Mercer
- Department of Biochemistry, University College of Wales, Aberystwyth, Dyfed, United Kingdom
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45
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Steel CC. Radio-detection high-performance liquid chromatographic enzyme assay for inhibitors of fungal sterol delta 14-reductase. JOURNAL OF CHROMATOGRAPHY 1991; 566:435-43. [PMID: 1939455 DOI: 10.1016/0378-4347(91)80260-j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
An enzyme assay for inhibitors of fungal sterol delta 14-reductase employing isocratic reversed-phase high-performance liquid chromatography is described. A Hypersil 5-microns octadecylsilyl (ODS) column (250 mm x 4.6 mm I.D.) was used and a mobile phase consisting of methanol-water-ethanol (86:4:10, v/v) was pumped at a flow-rate of 1.5 ml/min. Typical analysis times were 15 min. Using [4-14C]ignosterol as a substrate and an enzyme preparation from Saccharomyces cerevisiae, this method was used to compare the inhibition of sterol delta 14-reductase by the fungicides fenpropidin and fenpropimorph with three N-substituted 8-azadecaline compounds.
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Affiliation(s)
- C C Steel
- Department of Agrobiological Research, Dielsdorf, Switzerland
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Mikhailova NP, Sorokoletova EF, Durasova EN, Vyunov KA, Shapovalov OI. Sterol composition of nystatin-resistant Candida maltosa mutants. Folia Microbiol (Praha) 1991; 36:148-52. [PMID: 1823650 DOI: 10.1007/bf02814494] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Composition of sterol fractions of nystatin-resistant Candida maltosa strains was determined. Using UV-spectrometry, TLC and GLC-MS it was demonstrated that resistance to nystatin is connected with the composition alterations of yeast cell sterols. Block of different stages of ergosterol biosynthesis was revealed in some mutants, viz. C-24-transmethylation, delta 8----delta 7-isomerization, 14 alpha-demethylation, C-5(6)-dehydrogenation, reduction of C-14(15) and C-24(28) double bonds.
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Affiliation(s)
- N P Mikhailova
- All-Union Institute of Plant Material Hydrolysis, Leningrad, USSR
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Pascal S, Taton M, Rahier A. Oxidative C4-demethylation of 24-methylene cycloartanol by a cyanide-sensitive enzymatic system from higher plant microsomes. Biochem Biophys Res Commun 1990; 172:98-106. [PMID: 2222486 DOI: 10.1016/s0006-291x(05)80178-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Microsomes isolated from corn embryos (Zea mays) were shown to catalyse the C-4 monodemethylation of 28-[3H],24-methylene cycloartanol 1, leading to the corresponding 4 alpha-methyl sterol, cycloeucalenol 5. An enzymatic assay has been developed for the 4,4-dimethyl sterol 4-demethylase in higher plants. The demethylation process was shown to involve a 4-methyl, 4-hydroxymethyl derivative 2 which can be considered as the immediate metabolite of 1 by the 4-methyl oxidase. Compound 2 is further metabolized into 5 through a 4-methyl-4-carboxylic acid 3 and a 3-keto-4 alpha-methyl intermediate 4 which were identified. The conversion of 1 into 5 requires NADPH and molecular oxygen. The initial oxidative step was strictly dependent upon molecular oxygen, NADPH or NADH, and strongly inhibited by cyanide, whereas the overall process was completely insensitive to CO and to specific inhibitors of cytochrome P-450. It is concluded that in Zea mays microsomes, the C-4 demethylation of 1 results from a multistep process involving a terminal oxygenation system sensitive to cyanide which is distinct from cytochrome P-450 and in particular from that involved in the 14 alpha-demethylation of obtusifoliol.
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Affiliation(s)
- S Pascal
- Département d'Enzymologie Moléculaire et Cellulaire de l'IBMP, - CNRS UPR 406, Institut de Botanique, Strasbourg, France
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Nes W, Le PH. Evidence for separate intermediates in the biosynthesis of 24β-methylsterol end products by Gibberella fujikuroi. ACTA ACUST UNITED AC 1990. [DOI: 10.1016/0005-2760(90)90065-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Goad LJ, Berens RL, Marr JJ, Beach DH, Holz GG. The activity of ketoconazole and other azoles against Trypanosoma cruzi: biochemistry and chemotherapeutic action in vitro. Mol Biochem Parasitol 1989; 32:179-89. [PMID: 2494453 DOI: 10.1016/0166-6851(89)90069-8] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Trypanosoma cruzi epimastigotes in culture medium, and amastigotes and trypomastigotes in cultured human diploid lung cells were exposed to the antimycotic agent ketoconazole and their growth and/or sterol biosynthesis observed. Propagation of epimastigotes and amastigotes was impaired by concentrations of ketoconazole achievable in human serum, and amastigotes were more sensitive than were epimastigotes. Epimastigotes and trypomastigotes (non-dividing stage) displayed changes in their membrane sterol content such that the amounts of normal, end-product sterols (ergosterol, ergosta-5,7-dien-3 beta-ol, 24-ethylcholesta-5,7,22-trien-3 beta-ol, 24-ethylcholesta-5,7-dien-3 beta-ol) were notably decreased and the amounts of 14 alpha-methyl sterol precursors of these sterols (24-methylenedihydrolanosterol, obtusifoliol, lanosterol) were increased. Other azole drugs, itraconazole and fluconazole, when tested on epimastigotes, evoked the same qualitative pattern of changes in free sterols. Itraconazole was nearly as potent as ketoconazole, but fluconazole was significantly less potent. The nature of the sterols found in T. cruzi and the actions of azole drugs on their biosynthesis were similar in many respects to those observed in fungi and in Leishmania species. By analogy, it would seem that the primary mechanism of action of azole drugs on T. cruzi life-cycle stages is the impairment of the cytochrome P-450 sterol 14 alpha-demethylase. The consequent loss of normal sterols and accumulation of 14 alpha-methyl sterols may be responsible for the coincident retardation or cessation of growth.
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Affiliation(s)
- L J Goad
- Department of Biochemistry, University of Liverpool, U.K
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Berg D, Plempel M. Inhibitors of fungal sterol synthesis: squalene-epoxidation and C-14-demethylation. JOURNAL OF ENZYME INHIBITION 1989; 3:1-11. [PMID: 2487319 DOI: 10.3109/14756368909030359] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- D Berg
- Biochemical Department, Agrochemicals Division, Bayer AG, Monheim, FRG
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