ObjectivesIn our previous research, we have developed a new combination disinfectant, glutaraldehyde‐didecyldimethylammonium bromide (GD). It was verified that GD had a strong effect on both Escherichia coli and Staphylococcus aureus. In this work, Candida albicans was selected as an object, and it could be killed by GD. We aimed to investigate the cellular and molecular mechanism of GD effecting on C. albicans.Methods and ResultsThe results of sterilization experiment indicated that GD was effective on C. albicans. Flow cytometry and atomic absorption spectrometry were applied to detect cell membrane damage of C. albicans. Luciferase reaction and Bradford method were carried out to detect ATP content and protein quantitation. Transmission electron microscopy was used for intracellular organelles morphological observation. In order to study changes in mitochondrial membrane potential, Rh 123 was used as an indicator. DNA conformation analysis was performed by molecular modelling and circular dichroism. The results indicated that membrane permeability was increased rapidly owing to GD effect, and the leaked K+ and Mg2+ were about 12·1 and 12·4 times those of the control, respectively, at 10 min after GD treatment. Simultaneously, ATP and protein also leaked rapidly out of the cell. Mitochondrial membrane potential was destroyed, succinic dehydrogenase activity was significantly decreased and DNA conformation was changed because of GD action.ConclusionsGlutaraldehyde‐didecyldimethylammonium bromide disinfected C. albicans through distorting cell membrane integrity and permeability, disturbing the intracellular homeostasis by intracellular substances leakage, especially K+, Mg2+, ATP and protein, causing electrolyte imbalance of mitochondria, changing DNA structure, which finally led to cell death.Significance and Impact of the StudyThis study focused on the cellular and molecular mechanism of GD as a disinfectant against C. albicans. It is important to provide theoretical support to GD against Candida albicans in practical application.
Objective The aim of this study was to investigate the antibiofilm activity of coumarin against Candida albicans . Methods The efficacy of coumarin against biofilm formation and the mature biofilm of C. albicans was quantified by crystal violet (CV) staining and the 2,3-bis (2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetrazolium hydroxide (XTT) reduction assay. The effect of coumarin on C. albicans adhesion was assessed on polystyrene plates and by using the cell surface hydrophobicity (CSH) assay. The morphological transition of C. albicans was conducted in two types of hyphae-inducing media at 37 °C. The expression of hypha/biofilm-related genes was evaluated using qRT-PCR analysis. A rescue experiment involving addition of exogenous cyclic adenosine monophosphate (cAMP) was performed to investigate the involvement of cAMP in the yeast-to-hyphae transition. A C. albicans -infected Caenorhabditis elegans model was used to test the anti-virulence efficacy of coumarin. Results Treatment with coumarin strongly affected the capacity of C. albicans to form biofilm and significantly impaired the preformed mature biofilm. The addition of coumarin notably inhibited C. albicans adhesion, CSH, and filamentation . The expression of some adhesion- and hypha-related genes, including HWP1 , HYR1 , ECE1 , and ALS3 , was remarkably down-regulated upon exposure to coumarin. Supplementation with cAMP partly rescued the coumarin-induced defects in hyphal development. Finally, coumarin prolonged survival in C. albicans -infected nematodes. Conclusion Coumarin inhibited C. albicans biofilm, which was associated with attenuated adhesion and hyphal growth.
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