Plant‐derived tabersonine exert its antifungal activity by repressing the expression of ergosterol biosynthesis and cell wall mannoprotein encoding genes in Saccharomyces cerevisiae

Author(s):  
Wenhui Ma ◽  
Yu Zhao ◽  
Yanyan Wang
2004 ◽  
Vol 48 (10) ◽  
pp. 3871-3876 ◽  
Author(s):  
Sarit Markovich ◽  
Aya Yekutiel ◽  
Itamar Shalit ◽  
Yona Shadkchan ◽  
Nir Osherov

ABSTRACT The antifungal agent caspofungin (CAS) specifically interferes with glucan synthesis and cell wall formation. To further study the cellular processes affected by CAS, we analyzed a Saccharomyces cerevisiae mutant collection (4,787 individual knockout mutations) to identify new genes affecting susceptibility to the drug. This collection was screened for increased CAS sensitivity (CAS-IS) or increased CAS resistance (CAS-IR). MICs were determined by the broth microdilution method. Disruption of 20 genes led to CAS-IS (four- to eightfold reductions in the MIC). Eleven of the 20 genes are involved in cell wall and membrane function, notably in the protein kinase C (PKC) integrity pathway (MID2, FKS1, SMI1, and BCK1), chitin and mannan biosynthesis (CHS3, CHS4, CHS7, and MNN10), and ergosterol biosynthesis (ERG5 and ERG6). Four of the 20 genes (TPO1, VPS65, VPS25, and CHC1) are involved in vacuole and transport functions, 3 of the 20 genes (CCR4, POP2, and NPL3) are involved in the control of transcription, and 2 of the 20 genes are of unknown function. Disruption of nine additional genes led to CAS-IR (a fourfold increase of MIC). Five of these nine genes (SLG1, ERG3, VRP1, CSG2, and CKA2) are involved in cell wall function and signal transduction, and two of the nine genes (VPS67 and SAC2) are involved in vacuole function. To assess the specificity of susceptibility to CAS, the MICs of amphotericin B, fluconazole, flucytosine, and calcofluor for the strains were tested. Seven of 20 CAS-IS strains (with disruption of FKS1, SMI1, BCK1, CHS4, ERG5, TPO1, and ILM1) and 1 of 9 CAS-IR strains (with disruption of SLG1) demonstrated selective susceptibility to CAS. To further explore the importance of PKC in CAS susceptibility, the activity of the PKC inhibitor staurosporine in combination with CAS was tested against eight Aspergillus clinical isolates by the microdilution assay. Synergistic or synergistic-to-additive activities were found against all eight isolates by use of both MIC and minimum effective concentration endpoints.


2006 ◽  
Vol 50 (8) ◽  
pp. 2732-2740 ◽  
Author(s):  
Veronika Simons ◽  
John P. Morrissey ◽  
Maita Latijnhouwers ◽  
Michael Csukai ◽  
Adam Cleaver ◽  
...  

ABSTRACT Many plant species accumulate sterols and triterpenes as antimicrobial glycosides. These secondary metabolites (saponins) provide built-in chemical protection against pest and pathogen attack and can also influence induced defense responses. In addition, they have a variety of important pharmacological properties, including anticancer activity. The biological mechanisms underpinning the varied and diverse effects of saponins on microbes, plants, and animals are only poorly understood despite the ecological and pharmaceutical importance of this major class of plant secondary metabolites. Here we have exploited budding yeast (Saccharomyces cerevisiae) to investigate the effects of saponins on eukaryotic cells. The tomato steroidal glycoalkaloidα -tomatine has antifungal activity towards yeast, and this activity is associated with membrane permeabilization. Removal of a single sugar from the tetrasaccharide chain of α-tomatine results in a substantial reduction in antimicrobial activity. Surprisingly, the complete loss of sugars leads to enhanced antifungal activity. Experiments with α-tomatine and its aglycone tomatidine indicate that the mode of action of tomatidine towards yeast is distinct from that of α-tomatine and does not involve membrane permeabilization. Investigation of the effects of tomatidine on yeast by gene expression and sterol analysis indicate that tomatidine inhibits ergosterol biosynthesis. Tomatidine-treated cells accumulate zymosterol rather than ergosterol, which is consistent with inhibition of the sterol C24 methyltransferase Erg6p. However, erg6 and erg3 mutants (but not erg2 mutants) have enhanced resistance to tomatidine, suggesting a complex interaction of erg mutations, sterol content, and tomatidine resistance.


2008 ◽  
Vol 75 (4) ◽  
pp. 1129-1134 ◽  
Author(s):  
Jessica De Ingeniis ◽  
Nadia Raffaelli ◽  
Maurizio Ciani ◽  
Ilaria Mannazzu

ABSTRACT The yeast strain Pichia anomala DBVPG 3003 secretes a killer toxin (Pikt) that has antifungal activity against Brettanomyces/Dekkera sp. yeasts. Pikt interacts with β-1,6-glucan, consistent with binding to the cell wall of sensitive targets. In contrast to that of toxin K1, secreted by Saccharomyces cerevisiae, Pikt killer activity is not mediated by an increase in membrane permeability. Purification of the toxin yielded a homogeneous protein of about 8 kDa, which showed a marked similarity to ubiquitin in terms of molecular mass and N-terminal sequences. Pikt is also specifically recognized by anti-bovine ubiquitin antibodies and, similar to ubiquitin-like peptides, is not absorbed by DEAE-cellulose. However, Pikt differs from ubiquitin in its sensitivity to proteolytic enzymes. Therefore, Pikt appears to be a novel ubiquitin-like peptide that has killer activity.


Author(s):  
Gerrit J. P. Dijkgraaf ◽  
Huijuan Li ◽  
Howard Bussey

2019 ◽  
Vol 19 (10) ◽  
pp. 812-830 ◽  
Author(s):  
P. Marie Arockianathan ◽  
Monika Mishra ◽  
Rituraj Niranjan

The developing resistance in fungi has become a key challenge, which is being faced nowadays with the available antifungal agents in the market. Further search for novel compounds from different sources has been explored to meet this problem. The current review describes and highlights recent advancement in the antifungal drug aspects from plant and marine based sources. The current available antifungal agents act on specific targets on the fungal cell wall, like ergosterol synthesis, chitin biosynthesis, sphingolipid synthesis, glucan synthesis etc. We discuss some of the important anti-fungal agents like azole, polyene and allylamine classes that inhibit the ergosterol biosynthesis. Echinocandins inhibit β-1, 3 glucan synthesis in the fungal cell wall. The antifungals poloxins and nikkomycins inhibit fungal cell wall component chitin. Apart from these classes of drugs, several combinatorial therapies have been carried out to treat diseases due to fungal resistance. Recently, many antifungal agents derived from plant and marine sources showed potent activity. The renewed interest in plant and marine derived compounds for the fungal diseases created a new way to treat these resistant strains which are evident from the numerous literature publications in the recent years. Moreover, the compounds derived from both plant and marine sources showed promising results against fungal diseases. Altogether, this review article discusses the current antifungal agents and highlights the plant and marine based compounds as a potential promising antifungal agents.


2019 ◽  
Vol 15 (6) ◽  
pp. 648-658 ◽  
Author(s):  
Manzoor Ahmad Malik ◽  
Shabir Ahmad Lone ◽  
Parveez Gull ◽  
Ovas Ahmad Dar ◽  
Mohmmad Younus Wani ◽  
...  

Background: The increasing incidence of fungal infections, especially caused by Candida albicans, and their increasing drug resistance has drastically increased in recent years. Therefore, not only new drugs but also alternative treatment strategies are promptly required. Methods: We previously reported on the synergistic interaction of some azole and non-azole compounds with fluconazole for combination antifungal therapy. In this study, we synthesized some non-azole Schiff-base derivatives and evaluated their antifungal activity profile alone and in combination with the most commonly used antifungal drugs- fluconazole (FLC) and amphotericin B (AmB) against four drug susceptible, three FLC resistant and three AmB resistant clinically isolated Candida albicans strains. To further analyze the mechanism of antifungal action of these compounds, we quantified total sterol contents in FLC-susceptible and resistant C. albicans isolates. Results: A pyrimidine ring-containing derivative SB5 showed the most potent antifungal activity against all the tested strains. After combining these compounds with FLC and AmB, 76% combinations were either synergistic or additive while as the rest of the combinations were indifferent. Interestingly, none of the combinations was antagonistic, either with FLC or AmB. Results interpreted from fractional inhibitory concentration index (FICI) and isobolograms revealed 4-10-fold reduction in MIC values for synergistic combinations. These compounds also inhibit ergosterol biosynthesis in a concentration-dependent manner, supported by the results from docking studies. Conclusion: The results of the studies conducted advocate the potential of these compounds as new antifungal drugs. However, further studies are required to understand the other mechanisms and in vivo efficacy and toxicity of these compounds.


2019 ◽  
Vol 19 (4) ◽  
pp. 428-438 ◽  
Author(s):  
Nívea P. de Sá ◽  
Ana P. Pôssa ◽  
Pilar Perez ◽  
Jaqueline M.S. Ferreira ◽  
Nayara C. Fonseca ◽  
...  

<p>Background: The increasing incidence of invasive forms of candidiasis and resistance to antifungal therapy leads us to seek new and more effective antifungal compounds. </P><P> Objective: To investigate the antifungal activity and toxicity as well as to evaluate the potential targets of 2- cyclohexylidenhydrazo-4-phenyl-thiazole (CPT) in Candida albicans. </P><P> Methods: The antifungal activity of CPT against the survival of C. albicans was investigated in Caenorhabditis elegans. Additionally, we determined the effect of CPT on the inhibition of C. albicans adhesion capacity to buccal epithelial cells (BECs), the toxicity of CPT in mammalian cells, and the potential targets of CPT in C. albicans. </P><P> Results: CPT exhibited a minimum inhibitory concentration (MIC) value of 0.4-1.9 µg/mL. Furthermore, CPT at high concentrations (>60 x MIC) showed no or low toxicity in HepG2 cells and <1% haemolysis in human erythrocytes. In addition, CPT decreased the adhesion capacity of yeasts to the BECs and prolonged the survival of C. elegans infected with C. albicans. Analysis of CPT-treated cells showed that their cell wall was thinner than that of untreated cells, especially the glucan layer. We found that there was a significantly lower quantity of 1,3-β-D-glucan present in CPT-treated cells than that in untreated cells. Assays performed on several mutant strains showed that the MIC value of CPT was high for its antifungal activity on yeasts with defective 1,3-β-glucan synthase. </P><P> Conclusion: In conclusion, CPT appears to target the cell wall of C. albicans, exhibits low toxicity in mammalian cells, and prolongs the survival of C. elegans infected with C. albicans.</p>


Author(s):  
Anna Biernasiuk ◽  
Anna Berecka-Rycerz ◽  
Anna Gumieniczek ◽  
Maria Malm ◽  
Krzysztof Z. Łączkowski ◽  
...  

Abstract Recently, the occurrence of candidiasis has increased dramatically, especially in immunocompromised patients. Additionally, their treatment is often ineffective due to the resistance of yeasts to antimycotics. Therefore, there is a need to search for new antifungals. A series of nine newly synthesized thiazole derivatives containing the cyclopropane system, showing promising activity against Candida spp., has been further investigated. We decided to verify their antifungal activity towards clinical Candida albicans isolated from the oral cavity of patients with hematological malignancies and investigate the mode of action on fungal cell, the effect of combination with the selected antimycotics, toxicity to erythrocytes, and lipophilicity. These studies were performed by the broth microdilution method, test with sorbitol and ergosterol, checkerboard technique, erythrocyte lysis assay, and reversed phase thin-layer chromatography, respectively. All derivatives showed very strong activity (similar and even higher than nystatin) against all C. albicans isolates with minimal inhibitory concentration (MIC) = 0.008–7.81 µg/mL Their mechanism of action may be related to action within the fungal cell wall structure and/or within the cell membrane. The interactions between the derivatives and the selected antimycotics (nystatin, chlorhexidine, and thymol) showed additive effect only in the case of combination some of them and thymol. The erythrocyte lysis assay confirmed the low cytotoxicity of these compounds as compared to nystatin. The high lipophilicity of the derivatives was related with their high antifungal activity. The present studies confirm that the studied thiazole derivatives containing the cyclopropane system appear to be a very promising group of compounds in treatment of infections caused by C. albicans. However, this requires further studies in vivo. Key points • The newly thiazoles showed high antifungal activity and some of them — additive effect in combination with thymol. • Their mode of action may be related with the influence on the structure of the fungal cell wall and/or the cell membrane. • The low cytotoxicity against erythrocytes and high lipophilicity of these derivatives are their additional good properties. Graphical abstract


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Liang Sun ◽  
Jae Won Lee ◽  
Sangdo Yook ◽  
Stephan Lane ◽  
Ziqiao Sun ◽  
...  

AbstractPlant cell wall hydrolysates contain not only sugars but also substantial amounts of acetate, a fermentation inhibitor that hinders bioconversion of lignocellulose. Despite the toxic and non-consumable nature of acetate during glucose metabolism, we demonstrate that acetate can be rapidly co-consumed with xylose by engineered Saccharomyces cerevisiae. The co-consumption leads to a metabolic re-configuration that boosts the synthesis of acetyl-CoA derived bioproducts, including triacetic acid lactone (TAL) and vitamin A, in engineered strains. Notably, by co-feeding xylose and acetate, an enginered strain produces 23.91 g/L TAL with a productivity of 0.29 g/L/h in bioreactor fermentation. This strain also completely converts a hemicellulose hydrolysate of switchgrass into 3.55 g/L TAL. These findings establish a versatile strategy that not only transforms an inhibitor into a valuable substrate but also expands the capacity of acetyl-CoA supply in S. cerevisiae for efficient bioconversion of cellulosic biomass.


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