α-Bisabolol inhibits Aspergillus fumigatus Af239 growth via affecting microsomal ∆24-sterol methyltransferase as a crucial enzyme in ergosterol biosynthesis pathway

2017 ◽  
Vol 33 (3) ◽  
Author(s):  
Zahra Jahanshiri ◽  
Masoomeh Shams-Ghahfarokhi ◽  
Farnoush Asghari-Paskiabi ◽  
Reza Saghiri ◽  
Mehdi Razzaghi-Abyaneh
Keyword(s):  
Aspergillus Fumigatus ◽  
Ergosterol Biosynthesis ◽  
Biosynthesis Pathway ◽  
Sterol Methyltransferase

Ergosterol biosynthesis pathway in Aspergillus fumigatus

Steroids ◽  
2008 ◽  
Vol 73 (3) ◽  
pp. 339-347 ◽  
Author(s):  
Laura Alcazar-Fuoli ◽  
Emilia Mellado ◽  
Guillermo Garcia-Effron ◽  
Jordi F. Lopez ◽  
Joan O. Grimalt ◽  
...  
Keyword(s):  
Aspergillus Fumigatus ◽  
Ergosterol Biosynthesis ◽  
Biosynthesis Pathway

scholarly journals Azole Drug Import into the Pathogenic Fungus Aspergillus fumigatus

2015 ◽  
Vol 59 (6) ◽  
pp. 3390-3398 ◽  
Author(s):  
Brooke D. Esquivel ◽  
Adam R. Smith ◽  
Martin Zavrel ◽  
Theodore C. White
Keyword(s):  
Drug Resistance ◽  
Aspergillus Fumigatus ◽  
Fungal Infections ◽  
Pathogenic Fungus ◽  
Diffusion Mechanism ◽  
Ergosterol Biosynthesis ◽  
Common Mechanism ◽  
Facilitated Diffusion ◽  
Biosynthesis Pathway ◽  
Content Type

ABSTRACTThe fungal pathogenAspergillus fumigatuscauses serious illness and often death when it invades tissues, especially in immunocompromised individuals. The azole class of drugs is the most commonly prescribed treatment for many fungal infections and acts on the ergosterol biosynthesis pathway. One common mechanism of acquired azole drug resistance in fungi is the prevention of drug accumulation to toxic levels in the cell. While drug efflux is a well-known resistance strategy, reduced azole import would be another strategy to maintain low intracellular azole levels. Recently, azole uptake inCandida albicansand other yeasts was analyzed using [3H]fluconazole. Defective drug import was suggested to be a potential mechanism of drug resistance in several pathogenic fungi, includingCryptococcus neoformans,Candida krusei, andSaccharomyces cerevisiae. We have adapted and developed an assay to measure azole accumulation inA. fumigatususing radioactively labeled azole drugs, based on previous work done withC. albicans. We used this assay to study the differences in azole uptake inA. fumigatusisolates under a variety of drug treatment conditions, with different morphologies and with a select mutant strain with deficiencies in the sterol uptake and biosynthesis pathway. We conclude that azole drugs are specifically selected and imported into the fungal cell by a pH- and ATP-independent facilitated diffusion mechanism, not by passive diffusion. This method of drug transport is likely to be conserved across most fungal species.

Point mutation or overexpression of A. fumigatus cyp51B, encoding lanosterol 14α-sterol demethylase, leads to triazole resistance.

2021 ◽  
Author(s):  
Mariana Handelman ◽  
Zohar Meir ◽  
Jennifer Scott ◽  
Yona Shadkchan ◽  
Wei Liu ◽  
...  
Keyword(s):  
Aspergillus Fumigatus ◽  
Point Mutation ◽  
Clinical Isolate ◽  
Recipient Strain ◽  
Antifungal Treatment ◽  
Ergosterol Biosynthesis ◽  
Common Cause ◽  
Clinical Resistance

Aspergillus fumigatus is the most common cause of invasive fungal mold infections in immunocompromised individuals. Current antifungal treatment relies heavily on the triazole antifungals which inhibit fungal Erg11/Cyp51 activity and subsequent ergosterol biosynthesis. However, resistance, due primarily to cyp51 mutation, is rapidly increasing. A. fumigatus contains two Cyp51 isoenzymes, Cyp51A and Cyp51B. Overexpression and mutation of Cyp51A is a major cause of triazole resistance in A. fumigatus . The role of Cyp51B in generating resistance is unclear. Here we show that overexpression or mutation of cyp51B results in triazole resistance. We demonstrate that introduction of a G457S Cyp51B mutation identified in a resistant clinical isolate, results in voriconazole resistance in the naïve recipient strain. Our results indicate that mutations in cyp51B resulting in clinical resistance do exist and should be monitored.

scholarly journals Analysis of the ergosterol biosynthesis pathway cloning, molecular characterization and phylogeny of lanosterol 14α-demethylase (ERG11) gene of Moniliophthora perniciosa

2014 ◽  
Vol 37 (4) ◽  
pp. 683-693 ◽  
Author(s):  
Geruza de Oliveira Ceita ◽  
Laurival Antônio Vilas-Boas ◽  
Marcelo Santos Castilho ◽  
Marcelo Falsarella Carazzolle ◽  
Carlos Priminho Pirovani ◽  
...  
Keyword(s):  
Molecular Characterization ◽  
Ergosterol Biosynthesis ◽  
Biosynthesis Pathway ◽  
Moniliophthora Perniciosa

scholarly journals Electron donor cytochrome b5 is required for hyphal tip accumulation of sterol-rich plasma membrane domains and membrane fluidity in Aspergillus fumigatus

2020 ◽  
Author(s):  
Chi Zhang ◽  
Yiran Ren ◽  
Lu Gao ◽  
Huiyu Gu ◽  
Ling Lu
Keyword(s):  
Plasma Membrane ◽  
Aspergillus Fumigatus ◽  
Membrane Fluidity ◽  
Electron Donor ◽  
Cytochrome B5 ◽  
Normal Growth ◽  
Ergosterol Biosynthesis ◽  
Membrane Domains ◽  
Growth Defects ◽  
C Terminus

The electron donor cytochrome b5 (CybE/Cyb5) fuels the activity of the ergosterol biosynthesis-related P450 enzymes/P450s by providing electrons to P450s to promote ergosterol biosynthesis. Previous studies reported that lack of Aspergillus fumigatus (A. fumigatus) CybE reduces the proportion of ergosterol in total sterols and induces severe growth defects. However, the molecular characteristics of CybE and the underlying mechanism for CybE maintaining A. fumigatus growth remain poorly understood. Here, we found that CybE locates at the endoplasmic reticulum by its C-terminus with two transmembrane regions. Therefore, lack of the C-terminus of CybE is able to phenocopy a cybE deletion. Notably, cybE deletion reduced the accumulation of the sterol-rich plasma membrane domains (SRDs, the assembly platform of polarity factors/cell end markers and growth machinery) in hyphal tips and decreased membrane fluidity, which correspond to tardiness of hyphal extension and hypersensitivity to low temperature in cybE deletion mutant. Additionally, overexpressing another electron donor-heme-independent P450 reductase (CPR) significantly rescued growth defects and recovered SRD accumulation in deletion of cybE almost to the wild-type level, suggesting CybE maintaining the growth and deposition of SRDs in hyphal tips attributes to its nature as an electron donor. Protein pull-down assays revealed that CybE probably participates in metabolism and transfer of lipids, construction of cytoskeleton and mitochondria-associated energy metabolism to maintain the SRD accumulation in hyphal tips, membrane fluidity and hyphal extension. Findings in this study give a hint that inhibition of CybE may be an effective strategy for resisting the infection of the human pathogen A. fumigatus. Importance Investigating the knowledge of the growth regulation in the human opportunistic pathogen A. fumigatus is conducive to design new antifungal approach. The electron donor cytochrome b5 (CybE) plays a crucial role in maintaining the normal growth of A. fumigatus, however, the potential mechanism remains elusive. Herein, we characterized the molecular features of CybE and found the C-terminus with two transmembrane domains are required for its ER localization and functions. In addition, we demonstrated that CprA, an electron donor-heme-independent P450 reductase, provides a reciprocal function for the missing cytochrome b5 protein-CybE in A. fumigatus. CybE maintains the normal growth probably via supporting two crucial physiological processes, the SRD accumulation in hyphal tips and membrane fluidity. Therefore, our finding reveals the mechanisms underlying the regulatory effect of CybE on A. fumigatus growth and indicates that inhibition of CybE might be an effective approach for alleviating A. fumigatus infection.

Insights in the molecular mechanisms of an azole stress adapted laboratory-generated Aspergillus fumigatus strain

2021 ◽  
Author(s):  
Marion Aruanno ◽  
Samantha Gozel ◽  
Isabelle Mouyna ◽  
Josie E Parker ◽  
Daniel Bachmann ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Aspergillus Fumigatus ◽  
Molecular Mechanisms ◽  
Drug Transporters ◽  
Major Facilitator Superfamily ◽  
Ergosterol Biosynthesis ◽  
Azole Resistance ◽  
Drug Transporter

Abstract Aspergillus fumigatus is the main cause of invasive aspergillosis, for which azole drugs are the first-line therapy. Emergence of pan-azole resistance among A. fumigatus is concerning and has been mainly attributed to mutations in the target gene (cyp51A). However, azole resistance may also result from other mutations (hmg1, hapE) or other adaptive mechanisms. We performed microevolution experiment exposing an A. fumigatus azole-susceptible strain (Ku80) to sub-minimal inhibitory concentration of voriconazole to analyze emergence of azole resistance. We obtained a strain with pan-azole resistance (Ku80R), which was partially reversible after drug relief, and without mutations in cyp51A, hmg1, and hapE. Transcriptomic analyses revealed overexpression of the transcription factor asg1, several ATP-binding cassette (ABC) and major facilitator superfamily transporters and genes of the ergosterol biosynthesis pathway in Ku80R. Sterol analysis showed a significant decrease of the ergosterol mass under voriconazole exposure in Ku80, but not in Ku80R. However, the proportion of the sterol compounds was similar between both strains. To further assess the role of transporters, we used the ABC transporter inhibitor milbemycine oxime (MLB). MLB inhibited transporter activity in both Ku80 and Ku80R and demonstrated some potentiating effect on azole activity. Criteria for synergism were reached for MLB and posaconazole against Ku80. Finally, deletion of asg1 revealed some role of this transcription factor in controlling drug transporter expression, but had no impact on azole susceptibility. This work provides further insight in mechanisms of azole stress adaptation and suggests that drug transporters inhibition may represent a novel therapeutic target. Lay Summary A pan-azole-resistant strain was generated in vitro, in which drug transporter overexpression was a major trait. Analyses suggested a role of the transporter inhibitor milbemycin oxime in inhibiting drug transporters and potentiating azole activity.

scholarly journals Combining transcriptomics and metabolomics to reveal the underlying molecular mechanism of ergosterol biosynthesis during the fruiting process of Flammulina velutipes

BMC Genomics ◽  
2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Ruihong Wang ◽  
Pengda Ma ◽  
Chen Li ◽  
Lingang Xiao ◽  
Zongsuo Liang ◽  
...  
Keyword(s):  
Molecular Mechanism ◽  
Differentially Expressed ◽  
Flammulina Velutipes ◽  
Cdna Libraries ◽  
Ergosterol Biosynthesis ◽  
Biosynthesis Pathway ◽  
Fruiting Bodies ◽  
Regulatory Relationship ◽  
Illumina Hiseq ◽  
Hiv Drugs

Abstract Background Flammulina velutipes has been recognized as a useful basidiomycete with nutritional and medicinal values. Ergosterol, one of the main sterols of F. velutipes is an important precursor of novel anticancer and anti-HIV drugs. Therefore, many studies have focused on the biosynthesis of ergosterol and have attempted to upregulate its content in multiple organisms. Great progress has been made in understanding the regulation of ergosterol biosynthesis in Saccharomyces cerevisiae. However, this molecular mechanism in F. velutipes remains largely uncharacterized. Results In this study, nine cDNA libraries, prepared from mycelia, young fruiting bodies and mature fruiting bodies of F. velutipes (three replicate sets for each stage), were sequenced using the Illumina HiSeq™ 4000 platform, resulting in at least 6.63 Gb of clean reads from each library. We studied the changes in genes and metabolites in the ergosterol biosynthesis pathway of F. velutipes during the development of fruiting bodies. A total of 13 genes (6 upregulated and 7 downregulated) were differentially expressed during the development from mycelia to young fruiting bodies (T1), while only 1 gene (1 downregulated) was differentially expressed during the development from young fruiting bodies to mature fruiting bodies (T2). A total of 7 metabolites (3 increased and 4 reduced) were found to have changed in content during T1, and 4 metabolites (4 increased) were found to be different during T2. A conjoint analysis of the genome-wide connection network revealed that the metabolites that were more likely to be regulated were primarily in the post-squalene pathway. Conclusions This study provides useful information for understanding the regulation of ergosterol biosynthesis and the regulatory relationship between metabolites and genes in the ergosterol biosynthesis pathway during the development of fruiting bodies in F. velutipes.

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