• Korean Journal of Microbiology
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• v.44 no.4
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• pp.289-292
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• 2008

Trisodium phosphate 12 hydrate and citric acid monohydrate mixture showed the strong anti-sticking effect on Streptococcus mutans, Streptococcus mitis, and Streptococcus salivarius, which are adhered to glass beads. Each Streptococcus species was shaking-cultured in brain heart infusion broth containing three glass beads. After 18 hr, glass beads were slightly washed into normal saline by three-pin-pointed pincette. Each three glass-beads set was put into reagent -containing tubes, which have 40 mg of bits of weighing paper for gaining brushing effect as similar as brushing one's teeth. The tubes were shaken by vortex mixer for 10 min except non-oral microbe, Streptococcus agalactiae (5 min). The samples were colony-counted by serial agar dilution method. Experiment was repeated three times for each Streptococcus species. The relative ratios of bacterial de-adherence by reagents were calculated in comparison with normal saline control. The de-adherence degree of citric acid-trisodium phosphate-saline mixture (CTS, pH 6.0) against Streptococcus mutans came to an average of 12.5 times compared with normal saline control. Trisodium-saline (TS, pH 8.4) showed the average of 7.5 times, and citric acid-saline (CS, pH 4.6) showed 6.0 times compared to the control group. The bacterial de-adherence degree against Streptococcus salivarius was each 7.2,2.6 and 2.8 times in above reagent sequence in comparison with saline control. CTS and TS showed 2.4 and 3.4 times of anti-sticking effect on Streptococcus mitis respectively, but CS had no anti-sticking effect on this bacterium. CTS, TS and CS showed 0.7, 0.6, and 0.6 times on non-oral microbe, Streptococcus agalactiae, separately compared with saline control. These results show that oral Streptococcus mutans, Streptococcus salivarius, and Streptococcus mitis, which are causative of dental caries or subacute endocarditis, may be easily removed from oral cavity by CTS mixture. It is conceivable that our experimental results will enable the development of a new conceptive toothpaste to prevent dental caries or subacute endocarditis after drawing teeth.

• Tuberculosis and Respiratory Diseases
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• v.56 no.3
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• pp.261-268
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• 2004

Background : The resurgence of tuberculosis and outbreaks of multidrug resistant (MDR) tuberculosis have increased the emphasis for the development of new susceptibility testing of the Mycobacterium tuberculosis for the effective treatment and control of the disease. Conventional drug susceptibility testings, such as those using egg-based or agar-based media have some limits, such as the time required and difficulties in determining critical inhibitory concentrations, but these are still being used in many diagnostic laboratories because of no better lternatives, considering cost and accuracy. To overcome these limits, a rapid and simple method for new susceptibility testing, using live and dead assays, was applied for a bacterial cell viability assay to distinguish dead from live bacterial cells based on two-color fluorescence. Materials and Methods Strains : Forty strains were used in this study, 20 susceptible to all antituberculosis drugs and the other 20 resistant to the four first line antituberculosis drugs isoniazid, rifampicin, streptomycin and ethambutol. Antibiotics : The four antibiotics were dissolved in 7H9 broth to make the following solutions: $0.1{\mu}g\;isoniazid(INH)/m{\ell}$, $0.4{\mu}g\;rifampicin(RMP)/m{\ell}$, $4.0{\mu}g\;streptomycin(SM)/m{\ell}$ and $4.0{\mu}g\;ethambutol(EMB)/m{\ell}$. Results : Live and dead Mycobacterium tuberculosis cells fluoresced green and red with the acridin (Syto 9) and propidium treatments, respectively. These results are very well accorded with conventional drug susceptibility testing by proportional method on Lowensen-Jensen media (L-J) containing 4 drugs (INH, RMP, EMB and SM), showing a 93.7 % accordance rate in susceptible strains and 95% in resistant strains. Conclusion : The results of the drug susceptibility testing using the live and dead bacterial cell assay showed high accordance rates compared with the conventional proportion method on L-J. This finding suggests that the live and dead bacterial cell assay can be used as an alternative to conventional drug susceptibility testing for M. tuberculosis strains.

• Restorative Dentistry and Endodontics
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• v.34 no.6
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• pp.500-507
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• 2009

The purpose of this study is to compare the antibacterial effect of $Listerine^{(R)}$ on two microorganisms (P. gingivalis and E. faecalis) with various root canal irrigants (NaOCl, CHX, EDTA) and to identify possibility of using $Listerine^{(R)}$ as a root canal irrigant. Porphyromonas gingivalis ATCC 3327 and Enterococcus faecalis ATCC 29212 were used in this experiment. For the test irrigants, 0.5%, 1%, 2.5%, 5.25% NaOCl, 0.1%, 0.2%, 1%, 2% CHX, 0.5M EDTA (18.6% EDTA) and $Listerine^{(R)}$ were prepared. Distiled water was used as control. Two methods-1) Comparison of turbidity in broth and 2) Agar diffusion test-were used to determine the extent of antibacterial effect of $Listerine^{(R)}$ and to compare it with that of NaOCl, CHX, and EDTA. All solutions tested were effective against two bacterial strains compared with control (p < 0.001). Any concentration of NaOCl, CHX, and EDTA showed similarly high effectiveness against all bacterial strains. In all experiment, $Listerine^{(R)}$ showed significantly low antibacterial effect compared with the other root canal irrigants (p < 0.05). In conclusion, the results reflect remarkably low antibacterial effect of $Listerine^{(R)}$ as compared with root canal irrigants in general so it is not suitable for the root canal irrigant.

• Microbiology and Biotechnology Letters
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• v.40 no.1
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• pp.1-9
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• 2012

This study's aim was to isolate microorganisms producing agarase with a high activity, with possible applications in improving the performance of the pretreatment processes for bioethanol production. Marine algaes were collected from the south coast of Korea, from which three kinds of microorganisms were isolated. After a 4-day culture of these strains at $25^{\circ}C$, crude enzymes were obtained from culture supernatant or cell-free extract by ammonium sulfate precipitation and membrane dialysis. Agarase activity was observed in these crude enzymes. Notably higher specific activity was observed in the crude enzyme obtained from the culture supernatant rather than that from the cell-free extract. This indicates that a secreted enzyme has a much greater activity than a cellular enzyme. Crude enzymes from the GNUM08122 strain were inferred to have ${\alpha}$-agarase activity because release of p-nitrophenol was observed, possibly due to the cleavage of p-nitrophenyl-${\alpha}$-D-galactopyranoside. The 16S rRNA sequence of GNUM08122 showed a close relationship to Pseudoalteromonas issachenkonii KMM 3549 (99.8%) and Pseudoalteromonas tetraodonis IMA 14160 (99.7%), which led us to assign it to the genus Pseudoalteromonas. Biochemical and physiological study revealed that this strain can grow well at $40^{\circ}C$ under a wide range of pH (pH 4~8) in high-salt conditions (10% NaCl).

• Journal of Dairy Science and Biotechnology
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• v.32 no.2
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• pp.131-139
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• 2014

The aim of this study was to manufacture Cutting-Gouda cheese and to investigate the change in physicochemical properties of Cutting-Gouda cheese made with Lactobacillus rhamnosus_p1. Lactic acid bacteria were isolated from Gouda cheese ripened for more than 1 year. They were identified as 2 strains of L. rhamnosus, Lactobacillus casei, Lactobacillus curvatus, and Staphylococcus saprophyticus by 16S rDNA sequencing and named L. rhamnosus_p1, L. casei_p2, L. curvatus_p3, L. rhamnosus_p4 and S. saprophyticus_p5. The proteolytic activities of isolated strains against casein were measured using prepared skim milk agar plates. L. rhamnosus_p1 showed the highest proteolytic activity. Cutting-Gouda cheese was made with L. rhamnosus_p1, and its physicochemical properties (moisture, protein, fat, ash and free amino acid content) were measured during ripening periods. Because of the modified atmosphere packaging ($N_2{^-}$), there was no change in moisture, protein, fat, and ash in the experimental group. The total amount of free amino acids in the control and experimental group gradually increased during ripening periods. The sensory evaluation showed that the experimental group was preferable to the control group. This result suggests that L. rhamnosus_p1 has potential to be developed as a new starter for Gouda cheese.

• The Korean Journal of Pesticide Science
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• v.4 no.3
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• pp.82-88
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• 2000

The objective of this study was to determine if wood vinegar of Quercus mongolica Fisch has herbicidal activity. Growth of plants, such as barnyard grass (Echinochloa crus-gulli P. Beauv), quackgrass (Agropyron smithii RYDB), canola (Brassica napus L.), velvetleaf (Abutilon avicennae), indian jointvetch (Aeschynomene indica), and common sorghum (Sorghum bicolor) grown on agar batch treated with 0.01% wood vinegar were similar to that of plant without wood vinegar. The growth of such plants, however, reduced at $0.1{\sim}1%$ concentrations, and inhibited totally at >5% concentration. In greenhouse study, soil-applied wood vinegar did not inhibit tile growth of canola, barnyard grass, large crabgrass, and Abutilon avicennae even at the highest concentration, 80L $80L^{-1}\;10a^{-1}$, while foliar-applied wood vinegar did inhibit the growth of plants at higher than 40L $80L^{-1}\;10a^{-1}$. Growth of canola, barnyard grass, large crabgrass, and Abutilon avicennae treated with wood vinegar (80L $80L^{-1}\;10a^{-1}$) was reduced by 71, 46, 24, and 47%, respectively. In field experiment conducted at Chunchon and Taebeck, biomass of weeds treated with wood vinegar at less than 40L $80L^{-1}\;10a^{-1}$ were close to that of weeds treated without wood vinegar, while biomass of weeds at 80L $80L^{-1}\;10a^{-1}$ was reduced by 34-36%, compared to that of control, at both sites. However, the herbicidal activity of wood vinegar was much lower than that of glyphosate. Results in this study show that wood vinegar of Quercus mongolica Fisch has herbicidal activity, although the herbicidal activity was lower than that of glyphosate, a commercial herbicide.

• The Korean Journal of Pesticide Science
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• v.19 no.1
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• pp.64-70
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• 2015

In order to control garlic white rot (Sclerotium cepivorum), which threatens garlic production in farmers fields, soil solarization (solar sterilization), sclerotia germination inducers and effective microorganisms as biological control agents, and chemical fungicides have been used. Among them, fungicide has been largely used to reduce garlic white rot. In this study, the antifungal activities of five fungicides, prochloraz(a.i. 25%, EC), tebuconazole (a.i. 25%, WP), flutolanil (a.i. 15%, EC), iminoctadine tris-albesilate (a.i. 40%, WP) and isoprothiolane (a.i. 40%, EC) with different mode of action, in mycelial growth, sclerotia germination and sclerotia production, were tested. The inhibitory effects of the 5 fungicides on the mycelial growth, and sclerotia germination and production of garlic white rot pathogen (S. cepivorum T11-2) were investigated on potato dextrose agar (PDA) and their control efficacies were evaluated on garlic flakes. There was no mycelial growth of S. cepivorum T11-2 on PDA amended with $0.8{\mu}g\;mL^{-1}$ of prochloraz or $100{\mu}g\;mL^{-1}$ of tebuconazole. Also prochloraz and tebuconazole inhibited perfectively the sclerotia germination of the pathogen at 10 and $1.0{\mu}g\;mL^{-1}$, respectively. In spite of a very low activity of isoprothiolane in mycelial growth and sclerotia germination of S. cepivorum T11-2, it showed a good inhibitory activity against sclerotia production of S. cepivorum T11-2 on PDA amended with $1.67{\mu}g\;mL^{-1}$. Prochloraz, tebuconazole and flutolanil showed above 70% of control value when they were treated at $100{\mu}g\;mL^{-1}$ using the garlic flake cutting-method.

• The Korean Journal of Pesticide Science
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• v.11 no.3
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• pp.201-209
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• 2007

Characteristics of the 5 biopesticides that included Bacillus thuringiensis and on the domestic markets were investigated. These products were contained different strains of B. thuringiensis, for examples; product A and E was B. thuringiensis subsp aizawai; product B was B. thuringiensis; product C was B. thuringiensis Berline var. kurstaki; product D was B. thuringiensis var. kurstaki. Number of active spores were counted because they could influence the bio-activity against target pests. Only product C are contained the fixed quantity as its label, however, product D and E were a tenth part, and product A and B were a hundredth part of their descriptions. The pHs of product A and B were measured 3.67 and 3.73, and C, D and E were 5, respectively. Typical bypyramidal crystals produced from B. thuringiensis was found in only product C under a phase contrast microscope. For the uniform formulation of products that conformed whether B. thuringiensis were equally spreaded on the crops, B. thuringiensis in the C, D and E were equally grown on the nutrient agar medium As a results, product A were more different from product C than any other products. When product A and C were bioassayed against different larval stages of diamondback moth, their mortalities with spraying application were showed 100% after 48 hours.

• The Korean Journal of Mycology
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• v.38 no.1
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• pp.75-79
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• 2010

A total of 25 isolates of Fusarium fujikuroi were obtained from diseased rice plants in Korea from 2006 to 2007 to assess their resistance against fungicides prochloraz and benomyl + thiram. Minimal inhibitory concentration (MIC) values of F. fujikuroi isolates were examined by agar dilution method. Most of the isolates were sensitive to the fungicides. Out of 25 isolates, six were resistant to prochloraz and three to benomyl + thiram. In addition, the isolates CF245, CF249 and CF337 showed resistant to both fungicides. The progenies ($F_1$ isolates) obtained through two different crosses between sensitive parental isolates(CF202, CF232 and CF179) and resistant parental isolate (CF337) were evaluated for their mycelial growth at different temperatures and resistance against fungicides. Mycelial growth rate of $F_1$ isolates originated from CF202 $\times$ CF232 was similar to the parental isolates. However mycelial growth rate of $F_1$ isolates originated from CF179 $\times$ CF337 was faster than their parent isolates. In case of prochloraz, distribution ratio of sensitivity(S) to resistance(R) against to the fungicide of $F_1$ isolates originated from CF202 $\times$ CF232 and CF179 $\times$ CF337 was 86 : 14 and 78 : 22, respectively. In case of benomyl+thiram, all the $F_1$ isolates originated from CF202 $\times$ CF232 were sensitive to the fungicide, however ratio of sensitivity(S) to resistance(R) against to the fungicide of $F_1$ isolates originated from CF179 $\times$ CF337 was 35 : 65.

• Pediatric Infection and Vaccine
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• v.9 no.1
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• pp.79-84
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• 2002

Purpose : About 41% of obtained group A streptococci in the 1998 was reported as erythromycin-resistant streptococci in Seoul, Korea. The most common T serotype was T12, followed by T4 and T28. We'd like to monitor the serological changes and antibiotic sensitivity test of Streptococcus pyogenes obtained from the patients with pharyngotonsillitis and invasive diseases from 1999 through 2001. Also, it could be proposed to choose the proper antibiotic selection in the area where the rate of erythromycin-resistant streptococci is high. Methods : From Jan. 1999 to Oct. 2001, 208 isolates of group A streptococci were collected from inpatients and outpatients with pharyngotonsillitis, scarlet fever, and invasive infections in Seoul and Southern part of peninsula. All isolates were serotyped by T-agglutination, minimum inhibitory concentrations(MICs) which were determined by agar dilution methods, according to the guidelines of the National Committee for Clinical Laboratory Standards (NCCLS). Results : The most common T serotype was T12(29.8%), followed by T1(23.1%), T4 (14.9%). T1 was prominent serotype compared with previous year. T serotyping, among 25 isolates obtained from the patients with scarlet fever in Southern part of peninsula mostly, was T12, T1, and T4 in order of frequency. All the isolates tested were susceptible to penicillin, cefprozil, vancomycin, ceftriaxone, and chloramphenicol. However, 23 isolates(14.2%) was resistant to erythromycin and 18 isolates(11.1%) was resistant to clarithromycin. Serotype T12 was found to be the most resistant serotype to erythromycin and/or clarithromycin. Conclusion : High rate of erythromycin-resistant streptococci which surveyed in 1998 were reduced to 14.2% in this study. We should have to further evaluate the reason of decreased resistant strains and consider the resistant strains of streptococci in choosing the antibiotics. There was no serological characteristics according to the types of disease entities. Between the serologic distributions in Seoul and the Southern part of peninsula area are same, we could presume that the serological typing of strains obtained over the country may be not different.