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Fungal cell wall receptors relay messages about the state of the cell wall to the nucleus through the Cell Wall Integrity Signaling (CWIS) pathway. The ultimate role of the CWIS pathway is to coordinate repair of cell wall damage and to restore normal hyphal growth. Echinocandins such as micafungin represent a class of antifungals that trigger cell wall damage by affecting synthesis of β-glucans. To obtain a better understanding of the dynamics of the CWIS response and its multiple effects, we have coupled dynamic transcriptome analysis with morphological studies of Aspergillus nidulans hyphae in responds to micafungin. Our results reveal that expression of the master regulator of asexual development, BrlA, is induced by micafungin exposure. Further study showed that micafungin elicits morphological changes consistent with microcycle conidiation and that this effect is abolished in the absence of MpkA. Our results suggest that microcycle conidiation may be a general response to cell wall perturbation which in some cases would enable fungi to tolerate or survive otherwise lethal damage.
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A morphological, enzymatic and metabolic approach to elucidate apoptotic-like cell death in fungi exposed to h- and α-molybdenum trioxide nanoparticles
The present study compares for the first time the effects of h-MoO 3 and α-MoO 3 against two fungal strains: Aspergillus niger and Aspergillus flavus . The h-MoO 3 nanoparticles were more toxic to both fungi than α-MoO 3 . The toxic effects of h-MoO 3 were more pronounced toward A. flavus , which presented a growth inhibition of 67.4% at 200 mg L −1 . The presence of the nanoparticles affected drastically the hyphae morphology by triggering nuclear condensation and compromising the hyphae membrane. Further analysis of the volatile organic compounds (VOCs) produced by both fungi in the presence of the nanomaterials indicated important metabolic changes related to programmed cell death. These nanomaterials induced the production of specific antifungal VOCs, such as β-Elemene and t-Cadinol, by the fungi. The production of essential enzymes involved in fungal metabolism, such as acid phosphatase, naphthol-As-BI-phosphohydrolase, β-galactosidase, β-glucosidase and N -acetyl-β-glucosaminidase, reduced significantly in the presence of the nanomaterials. The changes in enzymatic production and VOCs corroborate the fact that these nanoparticles, especially h-MoO 3 , exert changes in the fungal metabolism, triggering apoptotic-like cell death responses in these fungi.
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- Award ID(s):
- 1705511
- PAR ID:
- 10095558
- Date Published:
- Journal Name:
- Nanoscale
- Volume:
- 10
- Issue:
- 44
- ISSN:
- 2040-3364
- Page Range / eLocation ID:
- 20702 to 20716
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/C8NR06470A
