• Korean Journal of Microbiology
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• v.52 no.1
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• pp.49-58
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• 2016

Compared to planktonic bacterial populations, biofilms have distinct bacterial community structures and play important ecological roles in various aquatic environments. Despite their ecological importance in nature, bacterial community structure and its succession during biofilm development in the Antarctic marine environment have not been elucidated. In this study, the succession of bacterial community, particularly during the early stage of biofilm development, in the Antarctic marine environment was investigated by pyrosequencing of the 16S rRNA gene. Overall bacterial distribution in biofilms differed considerably from surrounding seawater. Relative abundance of Gammaproteobacteria and Bacteroidetes which accounted for 78.9-88.3% of bacterial community changed drastically during biofilm succession. Gammaproteobacteria became more abundant with proceeding succession (75.7% on day 4) and decreased to 46.1% on day 7. The relative abundance of Bacteroidetes showed opposite trend to Gammaproteobacteria, decreasing from the early days to the intermediate days and becoming more abundant in the later days. There were striking differences in the composition of major OTUs (${\geq}1%$) among samples during the early stages of biofilm formation. Gammaproteobacterial species increased until day 4, while members of Bacteroidetes, the most dominant group on day 1, decreased until day 4 and then increased again. Interestingly, Pseudoalteromonas prydzensis was predominant, accounting for up to 67.4% of the biofilm bacterial community and indicating its important roles in the biofilm development.

• Preventive Nutrition and Food Science
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• v.8 no.1
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• pp.24-28
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• 2003

There is evidence to suggest that cranberry juice supplements improve the health of the urinary tract by inhibiting the binding of fimbriated uropathogenic E. coli to the bladder mucosa. In patients with neurogenic bladders, urinary tract infections (UTI) are particularly common and often poorly managed by antibiotic treatment. A double-blind, randomized, placebo-controlled trial was undertaken on 29 geriatric and spinal cord injured patients with dysfunctional bladders. They received three times daily at mealtimes a 4 oz bottle of cranberry juice (Ocean Spray Cranberries, USA) or a specially prepared synthetic placebo drink. Two episodes of UTI arose in week one of cranberry intake and none thereafter, compared to four episodes of UTI in 4 placebo patients in weeks four, six and 10. Mean bacterial adhesion counts on bladder cells of the patients rose during the first month of treatment in 71 % of the placebo patients compared to only 31 % of cranberry patients (p < 0.001). The difference persisted to some extent for the second and third months. Bacterial adhesion levels correlated with culture findings (higher adhesion and higher viable counts in urine) (p < 0.001), positive leukocyte nitrite tests (136$\pm$131 bacteria per cell versus 52$\pm$86 in negative tests) (p < 0.001), and higher white blood cell counts (> 10) per high power field (126$\pm$125 versus 48$\pm$85 bacteria per cell) (p<0.001). E. coli was the most frequently isolated organism (40% samples) followed by K. pneumoniae (17%) and a number of other uropathogens. Group B Streptococci, and coagulase negative Staphylococcus were recovered from urine in 4 samples but were not associated with any red blood cell presence. The daily intake of cranberry juice, in amounts which are not detrimental to long term compliance, appeared to have a role in reducing the risk of bladder colonization and infection in a highly susceptible patient population.

• Journal of dental hygiene science
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• v.15 no.2
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• pp.202-208
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• 2015

The aim of this retrospective study was to evaluate the relationship between periodontal health condition and the results of a new method such as Cariview which could evaluate the acidity of dental biofilms. Fifty four subjects more than 20 years old were selected for the candidates of this study. The periodontal health conditions of the candidates were divided into 4 groups according to the assessment of X-ray and Quantitative Light-induced Fluorescence-Digital (QLF-D; Inspektor Research Systems BV) images; gingivitis, slight periodontitis, moderate periodontitis, severe periodontitis. The biofilm acidogenicity of each subject was examined using Cariview (All in ONE BIO) according to manufacturer's instruction, and the Cariview score was calculated. The mean differences of Cariview score between 4 groups of periodontal health condition were examined by ANCOVA test with the covariance of decayed, missing, and filled teeth (DMFT) index. As a result, the mean Cariview score was different, however it was not significantly different from the 4 groups (p=0.12). The mean score was the lowest in the gingivitis group ($40.54{\pm}11.01$), and the highest in slight periodontitis group ($57.26{\pm}20.51$). In conclusion, the significant mean differences were not confirmed in Cariview score according to the periodontal health condition.

• Korean Journal of Clinical Laboratory Science
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• v.50 no.4
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• pp.438-443
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• 2018

The emergence of biofilms have generated urgent alarm in clinical and medicine manufacturing fields engaged in the search for novel antimicrobials from ethno-medicinal plants. The National Institutes of Health (NIH) has estimated that 70% of all microbial infections in the world are associated with biofilms. In addition, the emergence of strains resistant to conventional antibiotics has become a serious threat to global public health. Therefore, finding alternative medicines is a major issue in the field of integrative medicine. In this study, four different herb extracts were screened for biofilm formation and the activities of Klebsiella pneumoniae. Of them, Scutellaria scordifolia Fisch. ex Schrank extracts had inhibitory effects on bacterial growth and biofilm formation. The Scutellaia scordifolia Fisch. ex Schrank extracts did not cause any cytotoxicity to L929 cells. The growth of K. pneumoniae was inhibited compared to other comparators in the experimental group containing Scutellaia scordifolia Fisch. ex Schrank. In a group of experiments with plant extracts, a maximum of 60 times the level of living bacteria was confirmed compared to the controls without the addition of the Scutellaia scordifolia Fisch. ex Schrank extracts. In a group of experiments with a significantly lower level of fluorescence extraction, differential interference contrast imaging showed that the number of K. pneumonae was reduced. These results suggest that extracts of this plant be applied as antimicrobial agents against K. pneumoniae, particularly in biofilm forms.

• Microbiology and Biotechnology Letters
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• v.47 no.3
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• pp.465-472
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• 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 Life Science
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• v.29 no.1
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• pp.90-96
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• 2019

The objective of this study was to evaluate the potential of Diospyros malabarica stem extract, a natural materials, in oral health material. With this aim in mind, thin layer chromatography (TLC), TLC-bioautography, high-performance liquid chromatography (HPLC), electrospray ionization-mass spectrometry (ESI-MS), scanning electron microscopy (SEM), and real-time qPCR were performed. The antibacterial activity of D. malabarica stem extract against Streptococcus mutans KCTC3065 was confirmed in an n-hexane fraction with low polarity. The molecular weight of the antibacterial compound was estimated to be 188 by ESI-MS analysis. The inhibitory effects of the extract on biofilm formation and gene expression related to biofilm formation of S. mutans were determined by SEM and real-time PCR analysis. The extract inhibited the formation of S. mutans biofilms at D. malabarica stem extract concentrations of 1 mg/ml, as shown by SEM. The real-time PCR analysis showed that the expression of the gtfC gene, which is associated with biofilm formation, was significantly decreased in a dose-dependent manner. Based on the above results, it can be concluded that D. malabarica stem extracts, a natural materials, can be used in oral health products to suppress the formation of biofilms by inhibiting tooth adhesion of S. mutans, a causative agent of dental caries.

• Journal of the korean academy of Pediatric Dentistry
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• v.46 no.2
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• pp.135-138
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• 2019

The aim of this study was to investigate the susceptibility of Mutans streptococci in both planktonic and biofilm states to erythrosine. S. mutans was cultured in brain-heart infusion (BHI) broth. Erythrosine was diluted in BHI broth and prepared at a concentration range of $0.02-10000{\mu}g/L$. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were measured using the microdilution method. After forming biofilms on 96-well plates, the minimum biofilm inhibitory concentration (MBIC) and minimum biofilm eradication concentration (MBEC) were measured. S. mutans was susceptible to erythrosine in both planktonic and biofilm states. MIC and MBC values were both $19.5{\mu}g/L$ for the planktonic state, while MBIC and MBEC values were $313{\mu}g/L$ and $2500{\mu}g/L$, respectively, for the biofilm state. Erythrosine ($19.5{\mu}g/L$) exhibited a bactericidal effect on S. mutans (killing 99.9%) in the planktonic state. For biofilms, erythrosine inhibited biofilm growth and eradicated 99.9% of biofilm bacteria at higher concentrations than MIC and MBC. These MBIC and MBEC concentrations are much lower than known noxious doses, and the MIC, MBC, and MBIC values were even lower than clinical concentrations.

• Journal of the korean academy of Pediatric Dentistry
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• v.49 no.2
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• pp.140-148
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• 2022

This study aimed to evaluate the effect of silver diamine fluoride (SDF) and potassium iodide (KI) on the formation of cariogenic biofilm and surface roughness in vitro. A total of 48 bovine dentin specimens with artificially induced caries were prepared and divided into 3 groups of 16: untreated control, SDF-treated, and SDF-treated followed by KI (SDFKI). Ten specimens from each group were used to observe microbial adhesion. Multispecies cariogenic biofilms including Streptococcus mutans, Lactobacillus casei, and Candida albicans were cultured on the specimens. Microbes were cultured for 24 hours, and the colony-forming unit was calculated. The remaining specimens were observed by atomic force microscope and scanning electron microscope (SEM). The number of bacteria was significantly lower in the SDF and SDFKI groups. KI did not inhibit the antibacterial activity of SDF significantly. SEM images showed particles generated after SDF and SDFKI application were deposited on the dentin, but there was no significant difference in surface roughness between the 3 groups. This study confirmed that SDF and SDFKI application did not have a significant effect on the surface roughness of dentin, but effectively inhibited the formation of the early cariogenic bacterial film after 24 hours compared to the control.

• Journal of Food Hygiene and Safety
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• v.37 no.4
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• pp.285-295
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• 2022

The ability of volatile components of essential oils (EO) from cinnamon, clove, and lemongrass to inhibit biofilms formed on polyethylene and stainless steel by six types of food poisoning bacteria was investigated. The main components of cinnamon EO were identified as cinnamaldehyde (38.30%), linalool (9.61%), β-caryophyllene (8.90%), and 1,3,4-eugenol (8.19%). 1,3,4-Eugenol (61.84%) was the dominant component of clove EO. The major component of lemongrass EO was citral. Citral is a natural mixture of two isomeric acyclic monoterpene aldehydes: geranial (trans-citral, 19.11%) and neral (cis-citral, 19.23%). Among these major compounds, cinnamaldehyde, linalool, eugenol, and citral exhibited comparatively strong antimicrobial activity in the disc diffusion assay. Treatments with 0.1% eugenol and citral were highly effective on biofilm inhibition on both tested surfaces. Cinnamaldehyde (0.1%) was effective against biofilm formation by Listeria monocytogenes ATCC 19112 and Staphylococcus aureus KCCM 11812. These results suggested the potential of cinnamaldehyde, eugenol, and citral treatments in inhibiting the formation of biofilms by food poisoning bacteria.

• The Journal of the Korean dental association
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• v.50 no.9
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• pp.544-551
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• 2012

Dental caries is a biofilm-related oral disease, and continues to afflict the majority of the world's population. Although fluoride, delivered in various modalities, remains the mainstay for the prevention of caries, additional approaches are required to enhance its effectiveness. Natural products have been used as a major source of innovative and effective therapeutic agents throughout human history, and have shown promise as a source of components for the development of new drugs. In addition. studies using natural products to prevent or treat oral diseases such as dental caries have received a great deal of attention. A number of compounds, such as epicatechin, allicin and sanguinarine, isolated from natural products, have also been investigated for their efficacy against oral microbial pathogens. However, the use of natural products as an anti-caries agent in clinical practice was controversial because of inadequate knowledge concerning their mechanisms of action and chemical characterization. This study focuses on the current knowledge of natural products in dental caries prevention and suggests natural products are importance sources for the prevention of dental caries.