• Journal of Life Science
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• v.15 no.6 s.73
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• pp.955-960
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• 2005

Resistance to metronidazole, a key component of therapies against Helicobacter pylori, is common in clinical isolates. Resistance generally requires inactivation of rdxA (HP0954), and sometimes also frxA (HP0642), two related nitroreductase genes. Here we studied the effect of resistance to metronidazole on fitness of the gastric pathogen H. pylori. The effect of metronidazole resistance for H. pylori in culture was assessed first by looking at colonies formed by freshly constructed mutant derivatives of H. pylori strain 26695. Mutations resulting in metronidazole resistance caused premature death of H.pylori in stationary phase, but had no significant effect on early exponential growth. The effect of nitroreductase deficiencies on fitness in vivo was tested by infecting C57BL/6 mice with 1:1 mixtures of SS1 wild type and its isogenic metronidazole resistant derivatives. Inactivation of rdxA caused an inability to colonize mice in SS1 H. pylori strain. Derivatives of a metronidazole resistant strain that survived better in stationary phase, although remaining metronidazole resistant, could again colonize mice. In conclusion, metronidazole resistance diminishes H. pylori's fitness, but their costs can be suppressed by additional mutation.

• Experimental and Molecular Medicine
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• v.50 no.12
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• pp.2.1-2.12
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• 2018

Glucagon-like peptide-1 (GLP-1) has a broad spectrum of biological activity by regulating metabolic processes via both the direct activation of the class B family of G protein-coupled receptors and indirect nonreceptor-mediated pathways. GLP-1 receptor (GLP-1R) agonists have significant therapeutic effects on non-alcoholic fatty liver disease (NAFLD) and steatohepatitis (NASH) in animal models. However, clinical studies indicated that GLP-1 treatment had little effect on hepatic steatosis in some NAFLD patients, suggesting that GLP-1 resistance may occur in these patients. It is well-known that the gut metabolite sodium butyrate (NaB) could promote GLP-1 secretion from intestinal L cells. However, it is unclear whether NaB improves hepatic GLP-1 responsiveness in NAFLD. In the current study, we showed that the serum GLP-1 levels of NAFLD patients were similar to those of normal controls, but hepatic GLP-1R expression was significantly downregulated in NAFLD patients. Similarly, in the NAFLD mouse model, mice fed with a high-fat diet showed reduced hepatic GLP-1R expression, which was reversed by NaB treatment and accompanied by markedly alleviated liver steatosis. In addition, NaB treatment also upregulated the hepatic p-AMPK/p-ACC and insulin receptor/insulin receptor substrate-1 expression levels. Furthermore, NaB-enhanced GLP-1R expression in HepG2 cells by inhibiting histone deacetylase-2 independent of GPR43/GPR109a. These results indicate that NaB is able to prevent the progression of NAFL to NASH via promoting hepatic GLP-1R expression. NaB is a GLP-1 sensitizer and represents a potential therapeutic adjuvant to prevent NAFL progression to NASH.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.24 no.5
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• pp.423-431
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• 2021

Purpose: To assess the effect of combination probiotic Saccharomyces boulardii CNCM-I 3799 and Bacillus subtilis CU-1 in outpatient management of acute watery diarrhea in children. Methods: A randomized double-blind placebo-controlled study was conducted in 180 participants aged six months to five years with acute mild to moderate diarrhea. All were enrolled from six centers across India and centrally randomized to receive S. boulardii CNCM-I 3799 and B. subtilis CU-1 or a placebo along with oral rehydration salts and zinc supplementation. Each participant was followed up for three months to assess recurrence of diarrhea. Results: The mean duration of diarrhea in the probiotic and placebo groups were 54.16 hours and 59.48 hours, respectively. The difference in the duration of diarrhea in those administered with probiotic or placebo within 24 hours of diarrhea onset was 25.21 hours. Furthermore, the difference in duration of diarrhea was 13.84 hours (p<0.05) for participants who were administered with probiotics within 48 hours. There were no significant differences in the stool frequencies between the two arms. After three months, 15% in the probiotic group and 18.5% in the placebo group reported episodes of diarrhea. The mean duration of diarrhea was considerably lower in the probiotic group, 31.02 hours versus 48 hours in placebo (p=0.017). Conclusion: S. boulardii CNCM-I 3799 and B. subtilis CU-1 combination was effective in reducing the duration of diarrhea when administered within 48 hours of diarrhea onset. Similarly, it reduced recurrence of diarrhea and its intensity in the subsequent three months.

• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.1
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• pp.21-30
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• 2021

The purpose of this study is to investigate the antibacterial effects of indocyanine green (ICG) and near-infrared diode lasers on multispecies biofilms. Multispecies biofilms of Streptococcus mutans, Lactobacillus casei and Candida albicans were treated with different irradiation time using photosensitizer ICG and 808 nm near-infrared diode laser. Colony forming unit (CFU) was measured, and qualitative evaluation of biofilm was performed with confocal laser scanning microscopy (CLSM). Temperature measurement was conducted to evaluate photothermal effect. In the groups using ICG and diode laser, reduction in CFU was statistically significant, but the difference in antibacterial effect on L. casei and C. albicans with irradiation time was not significant, and similar results were confirmed with CLSM. Groups with ICG and diode laser showed higher temperature elevation than groups without ICG, and results of measured temperature were similar to the range of hyperthermia. In conclusion, ICG and near-infrared diode laser showed antibacterial effects on multispecies biofilms, but studies on protocol are necessary for clinical application.

• Journal of Korean society of Dental Hygiene
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• v.19 no.3
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• pp.387-397
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• 2019

Objectives: This study was conducted to examine the subjects' oral health status and changes in the oral environment after mouthwash with effervescent Vitamin C and its intake and to understand the impact on changes in the number of bacteria causing periodontal diseases in the oral cavity based on the oral health status and oral environmental condition. Methods: After obtaining approval from the Institutional Review Board of D-University, 45 people (24 in an experimental group and 21 in a control group) who participated in the oral health program were selected, among visitors of the Clinical Dental Hygienics Laboratory of D. University in B. Results: Based on the subjects' periodontal health status, the number of bacteria causing periodontal diseases in the oral cavity decreased in both experimental and control groups before and after the experiment. However, in the experimental group, it was significant when the Bleeding on Probing(BOP) level was below average, and Calculus index(CAL) was above average, in Aggregatibacter actinomycetemcomitans and the red complex. It was also significant when CAL was above average in the orange complex in the control group. Regarding bacterial changes in periodontal diseases based on the subjects' oral environmental condition, there was a significant change in the Adenosine Tri Phosphate (ATP : intraoral contaminants test) test in the oral cavity in A. actinomycetemcomitans and the red complex in the experimental group and in the O'Leary index in the control group. Further, there was a significant change in the orange complex in the ATP test in the experimental group. Conclusions: A comprehensive analysis of the results revealed that the oral health care program for dental hygiene decreased the number of bacteria causing periodontal diseases in the oral cavity in both experimental and control groups.

• 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.3
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• pp.321-328
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• 2022

The aim of this in-vitro study is to evaluate the effect of potassium iodide (KI) on erythrosine-mediated photodynamic therapy (PDT) against Streptococcus mutans biofilms. S. mutans ATCC 25175 was cultured to form a biofilm on a hydroxyapatite disk. After diluting erythrosine to 20 μM and KI to 10, 50, and 100 mM, respectively, PDT was performed. The number of surviving bacteria was calculated as colony forming units (CFU)/mL and the statistical significance of the difference between groups was confirmed by Bonferroni post-hoc analysis. Cell viability was visually evaluated using confocal laser scanning microscopy (CLSM). As a result of the experiment, a significant decrease (p < 0.05) in CFU was observed in the experimental groups in which PDT was performed after applying KI regardless of the concentration of KI. In addition, a significant reduction (p < 0.05) in CFU was observed in the experimental group to which 100 mM KI was applied compared to 10 mM KI. The same results were confirmed when observing CLSM. KI significantly improved the efficacy of erythrosine-mediated PDT on S. mutans biofilms at all concentrations. This may compensate for the low sensitivity of PDT to biofilm-state bacteria strains, but it is necessary to establish an optimal clinical protocol through further research.

• Journal of the korean academy of Pediatric Dentistry
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• v.49 no.2
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• pp.149-157
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• 2022

The aim of this study was to evaluate the effects of erythrosine-mediated photodynamic therapy (PDT) on Streptococcus mutans biofilm recovery by counting its colony-forming units (CFUs) and via confocal laser scanning microscopy analysis at different time points following PDT. In PDT, photosensitizer was an erythrosine. S. mutans ATCC25175 biofilms were irradiated using an LED curing light. Chlorhexidine (CHX) was used as positive control. After each antimicrobial treatment, samples were cultured to allow biofilm recovery. Viability was measured by calculating the CFU counts after treatment and after every 3 hours for up to 24 hours. Immediately after treatment, the PDT and CHX groups showed equally significant decreases in S. mutans CFU counts compared to the negative control. After 12 hours of reculture, the PDT group showed no significant difference in the decrease in CFU count compared to the negative control, whereas the CHX group showed significantly lower CFU counts throughout the 24-hour period. Erythrosine-mediated PDT can effectively inhibit S. mutans biofilm formation. However, biofilm recovery occurred earlier in the CHX group after PDT. This study provides insights into the clinical effectiveness of PDT in preventing dental caries.

• BMB Reports
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• v.55 no.9
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• pp.465-471
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• 2022

Understanding and monitoring virus-mediated infections has gained importance since the global outbreak of the coronavirus disease 2019 (COVID-19) pandemic. Studies of high-throughput omics-based immune profiling of COVID-19 patients can help manage the current pandemic and future virus-mediated pandemics. Although COVID-19 is being studied since past 2 years, detailed mechanisms of the initial induction of dynamic immune responses or the molecular mechanisms that characterize disease progression remains unclear. This study involved comprehensively collected biospecimens and longitudinal multi-omics data of 300 COVID-19 patients and 120 healthy controls, including whole genome sequencing (WGS), single-cell RNA sequencing combined with T cell receptor (TCR) and B cell receptor (BCR) sequencing (scRNA(+scTCR/BCR)-seq), bulk BCR and TCR sequencing (bulk TCR/BCR-seq), and cytokine profiling. Clinical data were also collected from hospitalized COVID-19 patients, and HLA typing, laboratory characteristics, and COVID-19 viral genome sequencing were performed during the initial diagnosis. The entire set of biospecimens and multi-omics data generated in this project can be accessed by researchers from the National Biobank of Korea with prior approval. This distribution of large-scale multi-omics data of COVID-19 patients can facilitate the understanding of biological crosstalk involved in COVID-19 infection and contribute to the development of potential methodologies for its diagnosis and treatment.

• Parasites, Hosts and Diseases
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• v.61 no.3
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• pp.282-291
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• 2023

Despite the recent progress in public health measures, malaria remains a troublesome disease that needs to be eradicated. It is essential to develop new antimalarial medications that are reliable and secure. This report evaluated the pharmacokinetics and antimalarial activity of 1,2,6,7-tetraoxaspiro[7.11]nonadecane (N-89) using the rodent malaria parasite Plasmodium berghei in vivo. After a single oral dose (75 mg /kg) of N-89, its pharmacokinetic parameters were measured, and t_1/2 was 0.97 h, T_max was 0.75 h, and bioavailability was 7.01%. A plasma concentration of 8.1 ng/ml of N-89 was maintained for 8 h but could not be detected at 10 h. The dose inhibiting 50% of parasite growth (ED₅₀) and ED₉₀ values of oral N-89 obtained following a 4-day suppressive test were 20 and 40 mg/kg, respectively. Based on the plasma concentration of N-89, we evaluated the antimalarial activity and cure effects of oral N-89 at a dose of 75 mg/kg 3 times daily for 3 consecutive days in mice harboring more than 0.5% parasitemia. In all the N-89-treated groups, the parasites were eliminated on day 5 post-treatment, and all mice recovered without a parasite recurrence for 30 days. Additionally, administering oral N-89 at a low dose of 50 mg/kg was sufficient to cure mice from day 6 without parasite recurrence. This work was the first to investigate the pharmacokinetic characteristics and antimalarial activity of N-89 as an oral drug. In the future, the following steps should be focused on developing N-89 for malaria treatments; its administration schedule and metabolic pathways should be investigated.