• Journal of Microbiology and Biotechnology
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• v.28 no.7
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• pp.1209-1216
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• 2018

This study aimed to evaluate the antimicrobial activity of 2-phenylethynyl-butyltellurium (PEBT) in Escherichia coli and the relation to its pro-oxidant effect. For this, we carried out the disk diffusion test, minimum inhibitory concentration (MIC) assay, and survival curve analysis. We also measured the level of extracellular reactive oxygen species (ROS), activity of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT), and level of non-protein thiols (NPSH). PEBT at 1.28 and 0.128 mg/disk exhibited antimicrobial capability in the disk diffusion test, with an MIC value of 1.92 mg/ml, whereas PEBT at 0.96, 1.92, and 3.84 mg/ml inhibited bacterial growth after a 9-h exposure. PEBT at 3.84, 1.92, and 0.96 mg/ml increased extracellular ROS production, decreased the intracellular NPSH level, and reduced the SOD and CAT activities. Glutathione or ascorbic acid in the medium protected the bacterial cells from the antimicrobial effect of PEBT. In conclusion, PEBT exhibited antimicrobial activity against E. coli, involving the generation of ROS, oxidation of NPSH, and reduction of the antioxidant defenses in the bacterial cells.

• Journal of Microbiology and Biotechnology
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• v.24 no.4
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• pp.465-474
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• 2014

This study was performed to investigate the inhibitory effects of brown algae extracts on histamine production in mackerel muscle. First, antimicrobial activities of brown algae extracts against Morganella morganii were investigated using a disk diffusion method. An ethanol extract of Ecklonia cava (ECEE) exhibited strong antimicrobial activity. The minimum inhibitory concentration (MIC) of ECEE was 2 mg/ml. Furthermore, the brown algae extracts were examined for their ability to inhibit crude histidine decarboxylase (HDC) of M. morganii. The ethanol extract of Eisenia bicyclis (EBEE) and ECEE exhibited significant inhibitory activities (19.82% and 33.79%, respectively) at a concentration of 1 mg/ml. To obtain the phlorotannin dieckol, ECEE and EBEE were subjected to liquid-liquid extraction, silica gel column chromatography, and HPLC. Dieckol exhibited substantial inhibitory activity with an $IC_{50}$ value of 0.61 mg/ml, and exhibited competitive inhibition. These extracts were also tested on mackerel muscle. The viable cell counts and histamine production in mackerel muscle inoculated with M. morganii treated with ${\geq}2.5 $ MIC of ECEE (weight basis) were highly inhibited compared with the untreated sample. Furthermore, treatment of crude HD-Cinoculated mackerel muscle with 0.5% ECEE and 0.5% EBEE (weight basis), which exhibited excellent inhibitory activities against crude HDC, reduced the overall histamine production by 46.29% and 56.89%, respectively, compared with the untreated sample. Thus, these inhibitory effects of ECEE and EBEE should be helpful in enhancing the safety of mackerel by suppressing histamine production in this fish species.

• Korean Journal of Microbiology
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• v.44 no.4
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• pp.358-361
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• 2008

Effect of extract of fermented dropwort (Oenanthe stolonifera) on growth of intestinal harmful/useful bacteria and enzyme activity were investigated in vitro. The extract showed strong inhibition on harmful microbes including Vibrio and Salmonella, but mild inhibition on Bifidobacterium longum in both agar plate and liquid cultivation. Minimum inhibitory concentration (MIC) value of B. longum was the highest among tested microbes. Inhibition effect of fermented extract on harmful microbes increased according to fermentation period. Extract of fermented dropwort showed inhibitory effects on activity of microbial ${\beta}$-glucuronidase and tryptophanase. The inhibitory effects were also proportional to fermentation period. As consequence, it is assumed that the uptake of fermented dropwort might be useful for human intestinal health.

• Journal of Environmental Health Sciences
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• v.31 no.2 s.83
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• pp.115-119
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• 2005

This study was performed to investigate inhibitory effect on growth of Staphylococcus aureus and Bacillus cereus in lactic acid, hydrogen peroxide and combination of lactic acid and hydrogen peroxide. The minimun inhibitory concentration (MIC) of lactic acid in Staphylococcus aureus were 2500 ppm at pH 7.0, 1250 ppm at pH 5.5, 6.0 and 6.5, while in Bacillus cereus 625 ppm at pH 5.5 and 6.0, 1250 ppm at pH 6.5 and 7.0, respectively. MICs of hydrogen peroxide in Staphylococcus aureus were 50 ppm at pH 6.0, 75 ppm at pH 6.5 and 7.0, while in Bacillus cereus was 75 ppm at pH 5.0, 5.5 and 6.0, respectively. MICs of combined treatment of lactic acid and hydrogen peroxide in Staphylococcus aureus were 1250 ppm of lactic acid with 25 ppm of hydrogen peroxide and 625 ppm of lactic acid with 50 ppm of hydrogen peroxide. When Bacillus cereus were with 1250 ppm of lactic acid with 50 ppm of hydrogen per-oxide and 625 ppm of lactic acid with 75 ppm of hydrogen peroxide at 6.5. The correlations between MICs of lactic acid and hydrogen peroxide in S. aureus and B. cereus obtained through the coefficient of determination ($R^2$). $R^2$ value were 0.9934 and 0.9986, respectively. The inhibitory effect of lactic acid and hydrogen peroxide in S. aureus and B. cereus could be confirmed from the result of this experiment.

• Journal of Microbiology and Biotechnology
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• v.32 no.10
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• pp.1315-1324
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• 2022

Fermentation is an effective process for providing various beneficial effects in functional beverages. Lactic acid bacteria and yeast fermentation-based biotransformation contribute to enhancement of nutritional value and digestibility, including lactose intolerance reduction and control of infections. In this study, the probiotic fermented fruit juice (PFJ) was produced by Lactobacillus plantarum TISTR 1465, Lactobacillus salivarius TISTR 1112, and Saccharomyces boulardii CNCM I-745 while mixed fruit juice (MFJ) was used as the basic medium for microorganism growth. The potential function, the anti-salmonella activity of PFJ, was found to be effective at 250 mg/ml of MIC and 500 mg/ml of MBC. Biofilm inhibition was performed using the PFJ samples and showed at least 70% reduction in cell attachment at the MIC concentration of Salmonella Typhi DMST 22842. The antioxidant activities of PFJ were determined and the results revealed that FSB.25 exhibited 78.40 ± 0.51 mM TE/ml by FRAP assay, while FPSB.25 exhibited 3.44 ± 0.10 mM TE/ml by DPPH assay. The volatile compounds of PFJ were characterized by GC-MS, which identified alcohol, aldehyde, acid, ester, ketone, phenol, and terpene. The most abundant organic acid and alcohol detected in PFJ were acetic acid and 2-phenylethanol, and the most represented terpene was β-damascenone. The sensory attributes showed scores higher than 7 on a 9-point hedonic scale for the FPB.25, illustrating that it was well accepted by panelists. Taken together, our results showed that PFJ could meet current consumer demand regarding natural and functional, fruit-based fermented beverages.

• Imaging Science in Dentistry
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• v.53 no.2
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• pp.145-151
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• 2023

Purpose: Prior to cone-beam computed tomography (CBCT), orthodontic competence included radiological interpretation. Nevertheless, maxillary impacted canines (MICs), because of their position and adjacent complex anatomy, have been challenging to interpret, particularly with regard to root resorption. Although CBCT cross-sectional reconstructions of MICs yielded clearer insights into its diagnosis and treatment planning, the value of simultaneously using 2 different cross-sectional or multiplanar reconstructions of the CBCT datasets - orthogonal and curved/panoramic multiplanar reconstructions - has hitherto not been considered. Materials and Methods: Both orthogonal and curved/panoramic multiplanar reconstruction series of 5 screenshots were each reconstructed from the 5 cm×5 cm CBCT datasets of 15 separate MICs. Fifteen credentialled and experienced orthodontist volunteers reviewed 2 separate PowerPoints of 15 randomized series each, 1 week apart. Their review considered 6 factors that could affect treatment: the position and level of the MIC, the presence or absence of root resorption, ankylosis, cysts, and dilaceration. Results: All 15 orthodontists were statistically similar regarding overall years of experience and of CBCT use. Although either reconstruction alone allowed the orthodontists to determine whether ankylosis and, to a lesser extent, most of the other features were present or absent in the MIC, reviewing both reconstructions together was necessary to determine whether root resorption was present or absent in the adjacent tooth. Conclusion: Reviewing both orthogonal and curved/panoramic multiplanar reconstructions was necessary to evaluate the presence or absence of root resorption in the teeth adjacent to MICs and that of many other features.

• Journal of Microbiology and Biotechnology
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• v.33 no.9
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• pp.1179-1188
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• 2023

Escherichia coli, particularly multidrug-resistant (MDR) strains, is a serious cause of healthcare-associated infections. Development of novel antimicrobial agents or restoration of drug efficiency is required to treat MDR bacteria, and the use of natural products to solve this problem is promising. We investigated the antimicrobial activity of dried green coffee (DGC) beans, coffee pulp (CP), and arabica leaf (AL) crude extracts against 28 isolated MDR E. coli strains and restoration of ampicillin (AMP) efficiency with a combination test. DGC, CP, and AL extracts were effective against all 28 strains, with a minimum inhibitory concentration (MIC) of 12.5-50 mg/ml and minimum bactericidal concentration of 25-100 mg/ml. The CP-AMP combination was more effective than CP or AMP alone, with a fractional inhibitory concentration index value of 0.01. In the combination, the MIC of CP was 0.2 mg/ml (compared to 25 mg/ml of CP alone) and that of AMP was 0.1 mg/ml (compared to 50 mg/ml of AMP alone), or a 125-fold and 500-fold reduction, respectively, against 13-drug resistant MDR E. coli strains. Time-kill kinetics showed that the bactericidal effect of the CP-AMP combination occurred within 3 h through disruption of membrane permeability and biofilm eradication, as verified by scanning electron microscopy. This is the first report indicating that CP-AMP combination therapy could be employed to treat MDR E. coli by repurposing AMP.

• Journal of Microbiology and Biotechnology
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• v.16 no.1
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• pp.46-51
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• 2006

The inhibitory effects of flavanone derivatives on Helicobacter pylori (HP) growth, infection and VacA toxininduced vacuolation were investigated. Among flavanones tested, ponciretin potently inhibited the growth of HP with a MIC value of 0.01 mg/ml and VacA toxin-induced vacuolation in HeLa cells with $IC_{50}$ value of 0.078 mM. However, other flavanones inhibited neither HP growth nor VacA toxininduced vacuolation. All flavanones tested did not inhibit HP infection to KATO III cells. Ponciretin also inhibited activation of procaspase-3 to caspase-3 in HeLa cell induced by HP VacA toxin, but did not affect Bax and Bcl-2 protein levels. These findings indicate that ponciretin inhibits growth as well as vacuolation by HP VacA toxin, which induces cell death via proteolytic activation of a cascade of caspases.

• The Korean Journal of Food And Nutrition
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• v.33 no.3
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• pp.223-236
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• 2020

In this study, a safety evaluation was conducted to confirm if the Enterococcus faecium CKDB003 strain obtained by selection from a mixed fermentation of fruit and milk is suitable for use as a probiotic. The MIC value for the 10 antibiotics specified in the EFSA guidance was below the acceptable cut-off value. The antibiotic resistance genes aac(6')-li, eatAv, and msr(C) exist by whole genome sequencing, but are in the chromosome and not in the plasmid, thus confirming that there is no possibility of transmission to other microorganisms. It was confirmed that cytolysin (cylA, cylB, cylI, cylL-l, cylL-s, cylM, cylR1, cylR2), aggregation substance (asa1, asp1), collagen adhesion (ace), enterococcal surface protein (esp), endocarditis antigen (efaA), hyaluronidase (hyl) and gelatinase (gelE) were not present in the genome by examining the genes of factors related to virulence. Also, the biochemical analysis showed no toxic enzyme activities, and no virulence genes were detected by the PCR method. Thus, the E. faecium CKDB003 strain can be safely used as a health functional food probiotic, based on the results of the safety assessment.

• Research in Plant Disease
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• v.13 no.3
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• pp.170-176
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• 2007

Effects of fungicides on the mycelial growth of Botrytis cinerea isolated from ginseng leaves were investigated by an agar dilution method. By using a agar dilution method, it was investigated the effect of fungicides, procymidone, carbendazim and the mixture with both of carbendazim and diethofencarb, on the mycelial growth of Botrytis cinerea isolates, which were isolated from infected leaves of ginseng in 2005 and 2006. With MIC (minimum inhibiton concentration) of procymidone against B. cinerea, pathogens were divided into two groups. While one showed the low MIC between 0.8 and $4.0{\mu}g/ml$, the other showed higher MIC above $20{\mu}g/ml$. In terms of the inhibition ratio of mycelial growth at the indicated concentration of procymidone, isolates of B. cinerea were divided into three groups; the sensitive, the intermediate resistant, and the resistant group. Each group was differentiated by $EC_{50}$; the sensitive group showed below $2.0{\mu}g/ml$, the intermediate resistant group between 2.0 to $5.0{\mu}g/ml$, and resistant group above $5.0{\mu}g/ml$. Compared with the ratio of resistant isolates of B. cinerea in 2005, the ratio in 2006 increased from 19.3% to 27.5%. Furthermore, the average $EC_{50}$ value of them increased from $10.0{\mu}g/ml$ in 2005 to $237.3{\mu}g/ml$ in 2006. The ratio of isolates showing the multiple resistance between procymidone and carbendazim was 40.2%, whereas the ratio was 4.0% showing the multiple resistance in the mixture.