• Journal of dental hygiene science
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• v.13 no.2
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• pp.182-190
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• 2013

Composition of oral microbial flora is suggested to play a role in the maintenance of oral health. Among them, Streptococcus mutans plays an essential role in the formation of dental plaque and it is being noticed as incipient infective bacteria of dental caries. The purpose of this study was to prepare the basic data about distribution of Streptococcus mutans detected from saliva by measuring colony density. It is well known that smoking as well as drinking is a factor of dental caries, however there are few investigations about distribution of Streptococcus mutans either smoking or drinking. The materials of this study were collected from students of dentistry college with general characteristics obtained by self-administered questionnaires. Students were asked to gently chew the paraffin to get saliva for 1 minute. Bacitracin disc in the culture medium was activated for 15 minutes, and then sample was incubated in the activated medium at $37^{\circ}C$ incubator for 48 hours. Streptococcus mutans colonization per 1 ml saliva was measured by the number of criteria. The severe levels of dental caries activity were significantly increased in the case of smoking (from 5.6% to 10%) or drinking (form 0% to 7%), respectively. Also, dental caries activity increased according to smoking and drinking periods longer. However, using the SPSS analytical process (Mann-Whitney's U), no significant differences were observed between the smoking and the non-smoking or the drinking and non-drinking, respectively. These results obtained from dental caries activity of saliva suggest that distribution of Streptococcus mutans following smoking or drinking can be used as a significant information for oral health.

• Journal of the Korean GEO-environmental Society
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• v.15 no.8
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• pp.5-11
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• 2014

In this study, chemical analysis and ecotoxicity tests of leachate from disposal site for foot-and-mouth disease carcasses (FMD leachate) were conducted to collect fundamental data that will be used to develop environmental risk assessment tools for FMD leachate. For chemical analysis, concentration of $Cl^-$, $NH{_4}{^+}-N$, Korea standard method indicators for detection of leachate released from animal carcasses burial site into groundwater and NRN (Ninhydrin-Reactive Nitrogens), a newly suggested screening test indicator to detect groundwater contamination by FMD leachate, were assessed. For ecotoxicity tests, luminescent bacteria (V. fischeri), micro-algae (P. subcapitata) and water flea (D. magna) were selected as test species. Correlation analysis between the concentration of $Cl^-$, $NH{_4}{^+}-N$, NRN and the toxicity to V. fischeri was performed to identify the better indicators to monitor FMD leachate contamination. From regression analysis, the concentration of the indicators in FMD leachate contaminated sample that induced halfmaximal toxic effect to V. fischeri was evaluated. Results obtained from this study can be applied to assess the risk by FMD leachate and to establish the guideline to manage risk in relation to FMD leachate.

• Korean Journal of Microbiology
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• v.46 no.1
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• pp.63-67
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• 2010

Proteases catalyze hydrolytic cleavage of a peptide bond between amino acids and occupy pivotal positions in application in physiological and commercial fields. During the screening for novel bacteria producing extracellular protease, two bacterial strains, WD12 and WD32, were isolated from rotten trees and they made clear zone on LB plates supplemented with 1% skim milk. The similarities of 16S rRNA gene sequence of either WD12 or WD32 to GenBank database showed the highest to Pseuoxanthomonas mexicana as 97.8 and 99.8%, respectively. Phylogenetic analysis showed that both isolated was located within the cluster comprising P. mexicana and P. japonesis. WD12 and WD32 were catalase- and oxidase-positive, Gram-negative rod strains. In case of WD12, it could assimilate malate, but could not assimilate D-mannose, which were different characteristics from P. mexicana. Both Pseuoxanthomonas sp. WD12 and WD32 optimally produced extracellular protease at $35-37^{\circ}C$, and maximal activity showed as 656 unit/ml and 267 unit/ml, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.3
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• pp.382-388
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• 2018

In this study, the SELEX method was used to screen for and select aptamers with high selectivity and affinity for Streptococcus mutans, which is the causative agent of dental caries. Aptamers are single stranded oligonucleotides of DNA or RNA with high selectivity and affinity for target molecules because of their specific three-dimensional structures that are used to collect biometric information. When compared to antibodies in vitro, aptamers are more advantageous because of their ease of use in the screening process, low cost, chemical stability, and lack of restrictions on the target molecules. We sorted DNA aptamers, which contain 44 bp or 38 bp primer sequences in 5' and 3', 39 bp random sequences in the middle.We then analyzed the character and affinity to S. mutans. Aptamers of specific oligonucleotides that combine with S. mutans were selected and these results are selectively fused to S. mutans. The results confirmed that DNA aptamers can be used for rapid diagnosis and treatment of dental caries caused by bacteria of the oral cavity, namely S. mutans.

• Korean Journal of Food Science and Technology
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• v.41 no.5
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• pp.515-521
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• 2009

The DEFT (direct epifluorescent filter technique)/APC (aerobic plate count) test was utilized to screen powdered Ramen soup samples (RS-1, RS-2) whether or not they have been microbial-decontaminated. The initial microbial loads of commercially-packaged samples were log DEFT 6.46 (RS-1) and 7.05 (RS-2), but the viable bacterial counts were log APC 2.74 (RS-1) and 1.95 (RS-2), respectively; this finding showed that they have been already decontaminated by methods other than irradiation. The same samples were then subjected to gamma irradiation at 0, 5 and 10 kGy in order to evaluate the microbial and physicochemical changes during post-irradiation storage for 6 months under room conditions ($10{\pm}3^{\circ}C$). The DEFT count was constant in irradiated samples even at different doses, but APC decreased with dose increases; this implies that the log DEFT/APC increased in a linear fashion with dose. No coliforms, yeasts and molds were detected in any of the samples, whereas the initially detected aerobic bacteria ($5.49{\times}10^2CFU/g$) were inactivated by 5 kGy or more and no growth was observed during the subsequent storage period. The pH of RS-1 was reduced by irradiation (p<0.01), but increased (p<0.01) with increasing storage time. Irradiation induced a reduction in volatile basic nitrogen (VBN), whereas an increase in thiobarbituric acid (TBA) values was observed. The storage time proved more influential than irradiation up to 10 kGy in terms of changes in the VBN and Hunter’s color values of powdered Ramen soups.

• Journal of Microbiology and Biotechnology
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• v.16 no.8
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• pp.1201-1209
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• 2006

The purpose of this study was to isolate probiotic lactic acid bacteria (LAB) that produce bile salt hydrolase (BSH), and to evaluate its effects on serum cholesterol level. One-hundred-twenty bacterial colonies were initially isolated from human feces, and five strains were selected after screening based on their resistance to acids, tolerance against bile salts, and inhibitory activity on Escherichia coli. The Lactobacillus plantarum strain with the highest level of BSH activity was identified using 16S rRNA sequences, and was named L. plantarum CK 102. L. plantarum CK 102 at a level of 1.36$\times$10$^8$cfu/ml survived in pH 2 buffer for 6 h and exhibited excellent tolerance for bile salt. Coculturing the strain with E. coli in MRS broth resulted in strong inhibition against growth of E. coli at 18 h. Furthermore, the potential effect of CK 102 on serum cholesterol level was evaluated in rats. Thirty-two rats [Sprague-Dawley (SD) male, 129$\pm$l g, 5 weeks old] were divided into four groups of eight each. For six weeks, Group 1 was fed a normal diet (negative control); Group 2 was fed a cholesterol-enriched diet (positive control); Group 3 was fed a cholesterol-enriched diet plus L. plantarum CK 102 at 1.0$\times$10$^7$cfu/ml; and Group 4 was fed a cholesterol-enriched diet plus L. plantarum CK 102 at 5.0$\times$10$^7$cfu/ml. Blood samples were collected, serum lipids were analyzed, and weights of the organs were measured. Total blood cholesterol level, triglyceride, LDL-cholesterol, and free-cholesterol values were lower in rats that were fed 1. plantarum CK 102 than in those not fed L. plantarum CK 102. This cholesterol lowering effect implies that L. plantarum CK 102 could be utilized as an additive for health-assistance foods. In conclusion, these results suggest that the 1. plantarum CK 102 isolated could be used commercially as a probiotic.

• Microbiology and Biotechnology Letters
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• v.44 no.1
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• pp.26-33
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• 2016

Dominant lactic acid bacteria (LAB) strains were isolated from traditional fermented foods to obtain rare ${\gamma}$-aminobutyric acid (GABA)-producing LAB. Out of 147 isolates, 23 strains that could produce GABA with 1% (w/v) L-monosodium glutamate (MSG) were first isolated. After further screening of these rare GABA-producing LAB by analysis of the glutamate decarboxylase and 16S rRNA gene sequences, Enterococcus faecium JK29 was isolated, and 1.56 mM of GABA was produced after 48 h cultivation in basic de Man, Rogosa, and Sharpe (MRS) medium. To enhance GABA production by E. faecium JK29, the culture conditions were optimized. When E. faecium JK29 was cultivated in optimized MRS medium containing 0.5% (w/v) sucrose and 2% (w/v) yeast extract with 0.5% (w/v) MSG, GABA production reached 14.86 mM after 48 h cultivation at initial conditions of pH 7.5 and $30^{\circ}C$.

• Microbiology and Biotechnology Letters
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• v.40 no.4
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• pp.389-395
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• 2012

T-RFLP (terminal restriction fragment length polymorphism) analysis, one of the most highly adopted culture-independent microbial community analysis methods, was applied to evaluate the colonization of probiotics in experimental animal gut. Lactic acid bacteria that exhibited cinnamoyl esterase activity were isolated from Korean fermented vegetables and identified by 16S ribosomal RNA sequence analysis. Lactobacillus plantarum KK3, which demonstrated high chlorogenic acid hydrolysis by cinnamoyl esterase activity, and acid/bile salt resistances, was cultured, freeze-dried, and fed to mice and the microbiota in their feces were monitored by T-RFLP analysis. The T-RF of L. plantarum was detected in the feces of mice after the start of administration and lasted at least 31 days after the initial 7 day feeding. T-RFLP analysis was considered a useful tool to evaluate the gut colonization of probiotic L. plantarum. In order to prove that L. plantarum was from viable cells, we reisolated L. plantarum in the feces using cinnamoyl esterase activity media as the screening step. The colonization of L. plantarum KK3 in the mouse gut was confirmed by this research.

• KSBB Journal
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• v.26 no.6
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• pp.517-522
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• 2011

In our previous study, we isolated and characterized a 1-deoxynojirimycin (DNJ)-producing bacterium, Bacillus subtilis MORI, from chungkookjang, a Korean traditional food. B. subtilis MORI was subjected to ${\gamma}$-irradiation and the resulting bacteria were screened for increased DNJ production. A mutant was identified that produced 7.6 times more DNJ and named B. subtilis MORI 3K-85. In this study, the protein profiles of both strains were compared by one-dimensional and two-dimensional gel electrophoresis (1-DE and 2-DE, respectively) under both native and denaturing conditions. The 1-DE native-PAGE and 1-DE SDS-PAGE analyses identified 5 and 7 bands, respectively, that were found at higher concentrations in B. subtilis MORI 3K-85 than in B. subtilis MORI. Similarly, 2-DE analyses identified 20 protein spots which were found at higher concentrations in B. subtilis MORI 3K-85. The peptide mass profiles of these 20 proteins were analyzed by MALDI-TOF and compared with peptide sequences of B. subtilis and B. amyloliquefaciens in the MASCOT database. This screening suggested that three dehydrogenases, an aldolase, a synthetase, an isomerase, a reductase, and a peroxidase are elevated in B. subtilis MORI 3K-85. Based on this data, one or more of the elevated 8 enzymes might be related to the DNJ biosynthetic pathway.

• Journal of Periodontal and Implant Science
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• v.46 no.5
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• pp.320-328
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• 2016

Purpose: Human saliva, as a vital part of the immune defense system, contains a number of distinct proteins and peptides. Recently human common salivary protein 1 (CSP1) has been identified as an abundant salivary protein and may play a role in promoting the binding of cariogenic bacteria to salivary pellicles. However, nothing else is known regarding the role of CSP1 in periodontology. The aim of this study was to quantify and compare CSP1 levels between healthy subjects and periodontal patients. Methods: This controlled clinical study was conducted in periodontally healthy individuals and patients with chronic periodontitis Chonbuk National University Hospital, with Institutional Review Board approval. Whole saliva samples were collected from 36 healthy subjects and 33 chronic periodontitis patients and analyzed. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immune blotting were conducted to ensure that anti-CSP1 monoclonal antibody (mAb) binds to CSP1 in human saliva. A sandwich enzyme-linked immunosorbent assay (ELISA) system was house-fabricated using mAb-hCSP1#14 and mAb-hCSP1#4 as a capture and a detector mAb, respectively. The CSP1 concentrations in saliva from 36 healthy subjects and 33 periodontal patients were quantified using the CSP1 sandwich ELISA system, and the results were analyzed using the Student's t-test. Results: Immunoblot analysis using mAb-hCSP1 as a probe confirmed that CSP1 in human saliva existed as a single band with a molecular weight of approximately 27-kDa. The quantification of CSP1 concentrations by CSP1 ELISA showed that the median values (25th to 75th percentiles) of periodontal patients and healthy subjects were 9,474 ng/mL (range, 8,434.10,139 ng/mL) and 8,598 ng/mL (range, 7,421.9,877 ng/mL), respectively. The Student's t-test indicated the presence of a statistically significant difference between the 2 groups (P=0.024). Conclusions: The presence of a significant difference in CSP1 levels between healthy subjects and periodontal patients suggests that CSP1 may be a potential biomarker for the detection or screening of periodontitis patients.