• Journal of Microbiology and Biotechnology
• /
• v.32 no.1
• /
• pp.37-45
• /
• 2022

The fungal cell wall and membrane are the principal targets of antifungals. Herein, we report that myricetin exerts antifungal activity against Candida albicans by damaging the cell wall integrity and notably enhancing the membrane permeability. In the presence of sorbitol, an osmotic protectant, the minimum inhibitory concentration (MIC) of myricetin against C. albicans increased from 20 to 40 and 80 ㎍/ml in 24 and 72 h, respectively, demonstrating that myricetin disturbs the cell wall integrity of C. albicans. Fluorescence microscopic images showed the presence of propidium iodide-stained C. albicans cells, indicating the myricetin-induced initial damage of the cell membrane. The effects of myricetin on the membrane permeability of C. albicans cells were assessed using crystal violet-uptake and intracellular material-leakage assays. The percentage uptakes of crystal violet for myricetin-treated C. albicans cells at 1×, 2×, and 4× the MIC of myricetin were 36.5, 60.6, and 79.4%, respectively, while those for DMSO-treated C. albicans cells were 28.2, 28.9, and 29.7%, respectively. Additionally, myricetin-treated C. albicans cells showed notable DNA and protein leakage, compared with the DMSO-treated controls. Furthermore, treatment of C. albicans cells with 1× the MIC of myricetin showed a 17.2 and 28.0% reduction in the binding of the lipophilic probes diphenylhexatriene and Nile red, respectively, indicating that myricetin alters the lipid components or order in the C. albicans cell membrane, leading to increased membrane permeability. Therefore, these data will provide insights into the pharmacological worth of myricetin as a prospective antifungal for treating C. albicans infections.

• The Journal of Advanced Prosthodontics
• /
• v.13 no.2
• /
• pp.100-106
• /
• 2021

PURPOSE. The purpose of this study is to compare the antibacterial activity of currently purchasable denture cleansers against Candida albicans. Materials and methods: This study used tablet-type denture cleansers, PolidentⓇ, CoolingdentⓇ and FittydentⓇ, along with liquid denture cleansers, HexamedineⓇ, ListerineⓇ and Apple vinegarⓇ. The antibacterial activities of denture cleansers were evaluated based on the number of C. albicans and concentrations of the denture cleansers. Results. In the 0.5 × 106 cfu/㎖ culture medium, the C. albicans' death rate of PolidentⓇ was significantly lower than those of FittydentⓇ, HexamedineⓇ, ListerineⓇ, and Apple vinegarⓇ(P<.05). In the 0.5 × 107 cfu/, the C. albicans' death rates of PolidentⓇ and CoolingdentⓇ were significantly lower than those of FittydentⓇ, HexamedineⓇ, ListerineⓇ and Apple vinegarⓇ(P<.05). The C. albicans' death rates of PolidentⓇ and CoolingdentⓇ were significantly decreased at 0.02 g and 0.01 g. The C. albicans' death rate of FittydentⓇ was significantly decreased at 0.005 g (P<.05). The C. albicans' death rate of HexamedineⓇ was significantly decreased at 1/16 dilution. The C. albicans' death rate of ListerineⓇ was decreased at 1/8 dilution, and the antibacterial activity of Apple vinegarⓇ was decreased at 1/4 dilution (P<.05). Conclusion. As the number of C. albicans increased, the antibacterial activities of the denture cleansers decrease. In the tablet-type denture cleanser, all denture cleansers showed 100% C. albicans' death rate when used at a dose of 1 tablet. One denture cleanser showed the same antibacterial effect with only 1/3 of a tablet. In the liquid type denture cleanser, the level of dilution required was different for each denture cleanser.

• Journal of Microbiology
• /
• v.38 no.2
• /
• pp.105-108
• /
• 2000

Oligonucleotide primers amplifying a 344 bp fragment on the integrin-like protein alpha-INT1p gene (${\alpha}$INT1) of Candida albicans were synthesized for screenign of C. albicans from clinicalsamples by the polymerase chain reaction (PCR). The PCR specifically amplified DNA from C. albicans and none from any other Candida, fungal, or human DNA in standard used here. The PCR assay showed that the primers (LH1 and LH2) were specific for 26 isolates of C. albicans from clinical smaples, whereas the positive fragment, 344 bp, was not amplified from 15 clinical isolates including 14 other medically important Candida species and an isolate of Saccharomyces cerevisiae. PCR was conducted on the urine samples of 20 patients and 4 samples were C. albicans positive. The detection limit of the PCR assay for C. albicans was shown to be approximately 10 cells/ml saline. The PCR system using 344 bp ${\alpha}$INT1 as a target is more specific and rapid than the conventional culture method, and the sensitive detection method is applicable to clinical diagnosis of C. albicans infections.

• Journal of Microbiology and Biotechnology
• /
• v.28 no.2
• /
• pp.181-189
• /
• 2018

Candida albicans is a major pathogenic fungus in humans, and meets at first the innate immune cells, such as macrophages, in its host. One important strategy of the host cell to kill C. albicans is to produce reactive oxygen species (ROS) by the macrophages. In response to ROS produced by the macrophages, C. albicans operates its defense mechanisms against them by expressing its oxidative stress response genes. Although there have been many research studies explaining the specific transcription factors and the expression of the oxidative stress genes in C. albicans, the regulation of the oxidative stress genes by chromatin structure is little known. Epigenetic regulation by the chromatin structure is very important for the regulation of eukaryotic gene expression, including the chromatin structure dynamics by histone modifications. Among various histone modifications, histone acetylation is reported for its direct relationship to the regulation of gene expression. Recent studies reported that histone acetyltransferases regulate genes to respond to the oxidative stress in C. albicans. In this review, we introduce all histone acetyltransferases that C. albicans contains and some papers that explain how histone acetyltransferases participate in the oxidative stress response in C. albicans.

• Journal of Microbiology and Biotechnology
• /
• v.26 no.3
• /
• pp.610-617
• /
• 2016

Candidiasis has posed a serious health risk to immunocompromised patients owing to the increase in resistant yeasts, and Candida albicans is the prominent pathogen of fungal infections. Therefore, there is a critical need for the discovery and characterization of novel antifungals to treat infections caused by C. albicans. In the present study, we report on the antifungal activity of the ethanol extract from Salvia miltiorrhiza against C. albicans and the possible mode of action against C. albicans. The increase in the membrane permeability was evidenced by changes in diphenylhexatriene binding and release of both 260-nm-absorbing intracellular materials and protein. In addition, inhibition of cell wall synthesis was demonstrated by the enhanced minimal inhibitory concentration in the presence of sorbitol and reduced (1,3)-β-D-glucan synthase activity. The above evidence supports the notion that S. miltiorrhiza has antifungal activity against C. albicans by the synergistic activity of targeting the cell membrane and cell wall. These findings indicate that S. miltiorrhiza displays effective activity against C. albicans in vitro and merits further investigation to treat C. albicans-associated infections.

• Journal of Microbiology and Biotechnology
• /
• v.30 no.12
• /
• pp.1827-1834
• /
• 2020

Candida albicans is a major fungal pathogen in humans. In our previous study, we reported that an ethanol extract from Aucklandia lappa weakens C. albicans cell wall by inhibiting synthesis or assembly of both (1,3)-β-D-glucan polymers and chitin. In the current study, we found that the extract is involved in permeabilization of C. albicans cell membranes. While uptake of ethidium bromide (EtBr) was 3.0% in control cells, it increased to 7.4% for 30 min in the presence of the A. lappa ethanol extract at its minimal inhibitory concentration (MIC), 0.78 mg/ml, compared to uptake by heat-killed cells. Besides, leakage of DNA and proteins was observed in A. lappa-treated C. albicans cells. The increased uptake of EtBr and leakage of cellular materials suggest that A. lappa ethanol extract induced functional changes in C. albicans cell membranes. Incorporation of diphenylhexatriene (DPH) into membranes in the A. lappa-treated C. albicans cells at its MIC decreased to 84.8%, after 60 min of incubation, compared with that of the controls, indicate that there was a change in membrane dynamics. Moreover, the anticandidal effect of the A. lappa ethanol extract was enhanced at a growth temperature of 40℃ compared to that at 35℃. The above data suggest that the antifungal activity of the A. lappa ethanol extract against C. albicans is associated with synergistic action of membrane permeabilization due to changes in membrane dynamics and cell wall damage caused by reduced formation of (1,3)-β-D-glucan and chitin.

• Journal of Oral Medicine and Pain
• /
• v.47 no.3
• /
• pp.126-134
• /
• 2022

Purpose: This study aimed to propose an efficient treatment approach for infection with different candida species. Methods: Fifty-three patients who presented with a chief complaint of oral mucosal pain and exhibited positive candida culture findings were divided into two groups (Candida albicans and non-albicans). Pain, mucosal manifestations, salivary flow rates, durations of disease and treatment, and responses to treatment (nystatin and clonazepam) were investigated in both groups. Results: Patients in the C. albicans group exhibited more prominent clinical characteristics (erythematous lesions, tongue coatings, and hyperalgesia) than those in the non-albicans group. In total, 70% of patients in the non-albicans group showed no abnormalities in the oral mucosa. Patients in the C. albicans group showed increased resistance to nystatin treatment compared to those in the non-albicans group, especially with longer disease durations. The patients resistant to nystatin treatment showed positive responses to clonazepam. Conclusions: Patients with oral mucosal pain should be tested for the presence of Candida, even in the absence of mucosal abnormalities, especially those infected with non-albicans species. If no response to antifungal therapy is observed, treatment with clonazepam should be initiated, especially in patients infected with C. albicans.

• Journal of dental hygiene science
• /
• v.14 no.1
• /
• pp.1-6
• /
• 2014

The purpose of this study was to investigate the killing effect of Candida albicans on hairless mouse-2 (HRM-2) mouse tissues. We tested the effectiveness of a non-thermal atmospheric pressure plasma in killing C. albicans strains. The viability of C. albicans was determined by counting the colony forming units (CFU), after non-thermal atmospheric pressure plasma treatment. When non-thermal atmospheric pressure plasma was repeatedly treated on mouse skin which inoculated with C. albicans. The C. albicans cells were planted on skin tissue, and then the infected mouse tissue was exposed to non-thermal atmospheric pressure plasma for 0 sec, 60 sec, 180 sec and 300 sec. The death rate of C. albicans was increased in dependent with treatment times. The three times of non-thermal atmospheric pressure plasma at the interval of 10 minutes significantly showed the 6 log CFU/ml reduction of death rate on HRM-2 mouse tissues. Thus, non-thermal atmospheric pressure plasma could be used for the disinfection of C. albicans on oral surface.

• Microbiology and Biotechnology Letters
• /
• v.47 no.3
• /
• pp.465-472
• /
• 2019

Candida albicans is an opportunistic human pathogen that causes infections. Candidiasis is often related to antifungal resistance because the pathogen has the ability to form biofilms. In a previous study, we found that the Salvia miltiorriza ethanol extract demonstrated anticandidal activity by altering membrane permeability and inhibiting the cell wall synthesis in C. albicans. Our results here demonstrate that $78{\mu}g/ml$ of the S. miltiorriza extract significantly diminished the early stage biofilms formed by 10 clinical C. albicans isolates by 51.3%; this was analyzed by 2,3-Bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide salt (XTT) reduction assay. The effect of the S. miltiorrhiza extract on the adhesion of C. albicans cells to polystyrene plates and germ tube formation was examined via microscopic investigation. Although the density of the adhered cells was remarkably reduced up on incubation with $39{\mu}g/ml$ S. miltiorrhiza extract, germ tube formation by C. albicans was rarely affected. Quantitative real-time PCR analysis showed that the S. miltiorrhiza extract downregulated the expression of C. albicans hypha-specific genes, EAP1 by 34.7% (p < 0.001), ALS1 by 45.0% (p < 0.001), ALS3 by 48.1% (p < 0.001), and ECE1 by 21.3% (p = 0.006), respectively. Our data suggest that the S. miltiorrhiza ethanol extract significantly inhibited the early stage of biofilm formation by C. albicans by interfering with cell adhesion, by downregulating EAP1, ALS1 and ALS3, and presumably by modifying the cell wall and membrane structure.

• Journal of Microbiology and Biotechnology
• /
• v.27 no.2
• /
• pp.395-404
• /
• 2017

Fungal cell walls and cell membranes are the main targets of antifungals. In this study, we report on the antifungal activity of an ethanol extract from Paeonia lactiflora against Candida albicans, showing that the antifungal activity is associated with the synergistic actions of preventing cell wall synthesis, enabling membrane depolarization, and compromising permeability. First, it was shown that the ethanol extract from P. lactiflora was involved in damaging the integrity of cell walls in C. albicans. In isotonic media, cell bursts of C. albicans by the P. lactiflora ethanol extract could be restored, and the minimum inhibitory concentration (MIC) of the P. lactiflora ethanol extract against C. albicans cells increased 4-fold. In addition, synthesis of $(1,3)-{\beta}-{\small{D}}-glucan$ polymer was inhibited by 87% and 83% following treatment of C. albicans microsomes with the P. lactiflora ethanol extract at their $1{\times}MIC$ and $2{\times}MIC$, respectively. Second, the ethanol extract from P. lactiflora influenced the function of C. albicans cell membranes. C. albicans cells treated with the P. lactiflora ethanol extract formed red aggregates by staining with a membrane-impermeable dye, propidium iodide. Membrane depolarization manifested as increased fluorescence intensity by staining P. lactiflora-treated C. albicans cells with a membrane-potential marker, $DiBAC_4(3)$ ((bis-1,3-dibutylbarbituric acid) trimethine oxonol). Membrane permeability was assessed by crystal violet assay, and C. albicans cells treated with the P. lactiflora ethanol extract exhibited significant uptake of crystal violet in a concentration-dependent manner. The findings suggest that P. lactiflora ethanol extract is a viable and effective candidate for the development of new antifungal agents to treat Candida-associated diseases.