• Korean Journal of Ecology and Environment
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• v.37 no.4 s.109
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• pp.363-367
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• 2004

For comparative analysis of the eubacterial community structure at 8 sampling sites throughout the Nak-Dong River, FISH (fluorescence in situ hybridization) method was employed. The total ratio of each determined eubacterial group such as ${\alpha}\;{\cdot}\;{\beta}\;{\cdot}\;{\gamma}-subclasses$proteobacteria and Cytophaga-Flavobacterium(CF) group to total counts(DAPI) at each site varied 9.3-42.5% with the highest value at uppermost part. And each ratio of determined eubacterial groups reached mostly under 10% except that of CF group (23%) at uppermost part. Furthermore, compared to lower part, upper part represented unexpectedly higher proportions of ${\gamma}-subclass$ proteobacteria comprised almost fast growing bacteria on degradable organics. Also the variations of ammonia-oxidizing bacteria ranged from $2.7{\times}10^4$ to $18.0{\times}10^4$ cells $mL^{-1}$ with the lowest value in lower part and the highest value in mid part whereas those of nitrite-oxidizing bacteria varied 5.2-7.7{\times}10^4$ cells $mL^{-1}$ without noticeable differences throughout the sites. Additionally, the ratio of nitrifying bacteria to total counts ranged from 1.0% to 13.6% with no differences between ammonia-oxidizing bacteria and nitrite-oxidizing bacteria. In conclusion, FISH method introduced in this study for monitoring, normally used for the quantitative analysis of bacteria, provided also good information on their environmental status in the Nak-Dong River.

• Proceedings of the Korean Society of Food Hygiene and Safety Conference
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• 1996.06a
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• pp.51-62
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• 1996

• Journal of Life Science
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• v.13 no.3
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• pp.298-307
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• 2003

To figure out the conserved genes and newly added genes at each phylogenetic level of Archaea, COG (clusters of orthologous groups of proteins) algorithm was applied. The number of conserved genes within 9 species of Archaea was 340 and that of 8 species of Euryarchaeota was 388. Many of conserved 265 COGs, which are specific to Archaea and absent in Bacteria and S. cerevisiae, were concerned with 'information storage and processing' (94 COG, 35.5%) and 'metabolism' (82 COG, 30.9%). COGs related to these functions were assumed as highly conserved and permit peculiar life form to Archaea. It seemed that there was some difference in 'nucleotide transport and metabolism' and there was little difference in 'information storage and processing' between Euryarchaeota and Crenarchaeota. Marine-origin Euryarchaeota showed different conserved COGs with terrestrial Euryarchaeota. Conserved COGs, related to carbohydrate transport and metabolism and others, were different between marine- and terrestrial-origin Euryarchaeota. Hence it was assumed that their physiology might be different. This study may help to understand the origin and conserved genes at each phylogenetic level of marine-origin Euryarchaeota and may help in the mining of useful genes in marine Archaea as Manco et al. (Arch. Biochem. Biophy. 373, 182 (2000)).

• Journal of Yeungnam Medical Science
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• v.5 no.2
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• pp.129-139
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• 1988

Vaginitis is one of the most common disease in gynecologic field in recent days. About 90% of these patients suffer from the infection of the vagina caused by Gardnerella vaginalis, Candida, or Trichomonas, either alone or in combination. For the effective diagnosis and management, it is essential to get an accurate identification of the causative agent. Applying simple and easy diagnostic methods such as pH of vaginal discharge, amine test and microscopic examination of wet mount preparation of normal saline and 10% KOH to 549 cases of randomly selected patients visiting Out-patient Department of Obstetrics and Gynecology of Yeung-nam University Hospital through May 1st to Sept. 31st, 1987, the following results were obtained. 1. In the Gardnerella vaginitis vaginal pH was more than 5.0 in 81.0% of total cases, positive amine test in 62.8%, decreased lactobacilli in 77.4% & decreased WBC counts in 70.1%, In the Trichomonas vaginitis vaginal pH more than 5.0 was noted in 93.3% of the cases, negative amine test in 90%, decreased lactobacilli in 90% & increased WBC counts in 93.3%, whereas Candida vaginitis and normal groups showed vaginal pH of 3.0~4.0 in 83.2%, negative amine test in 100%, normal distribution of lactobacilli in 89.7%, normal WBC counts in 72.4%. 2. The accuracy rates of physical diagnosis by wet mount preparation of normal saline and 10% KOH revealed 26.3%, 47.5% % 70,0% in Gardnerella vaginitis, Candida vaginitis, and Trichomonas vaginitis, respectively. The vaginal pH and amine test showed 83.2% of accuracy rate in Candida vaginitis group, 60.6% in Gardnerella vaginitis group and 83.3% III Trichomonas vaginitis group. 3. In 23 cases of Gardnerella vaginitis showing vaginal pH of 3.0 or 4.0 and positive amine test, the clue cells were observed in 10% or less in 12 cases, 30% in 5 cases, 50% in 4 cases and 50% or more in 2 cases. In summary vaginal pH and amine test could be useful in screening and differentiating the different types of infectious vaginitis. Furthermore by adding microscopic examination of normal saline and 10% KOH wet mount preparation to them, they not only could obtain higher diagnostic accuracy rate but would be more valuable in selecting the patients requiring cultures to confirm the diagnoses.

• Journal of Life Science
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• v.28 no.3
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• pp.351-356
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• 2018

L-Serine dehydratase (LSD) is an iron-sulfur containing enzyme that catalyzes the conversion of L-serine to pyruvate and ammonia. Among the bacterial amino acid dehydratases, it appears that only the L-serine specific enzymes utilize an iron-sulfur cluster at their catalytic site. Moreover, bacterial LSDs are classified into four types based on structural characteristics and domain arrangement. To date, only the LSD enzymes from a few bacterial strains have been studied, but more detailed investigations are required to understand the catalytic mechanism of various bacterial LSDs. In this study, LSD type II from Mycobacterium tuberculosis (MtLSD) H37Rv was expressed and purified to elucidate the biochemical and catalytic properties using the enzyme kinetic method. The L-serine saturation curve of MtLSD exhibited a typically sigmoid character, indicating an allosteric cooperativity. The values of $K_m$ and $k_{cat}$ were estimated to be $59.35{\pm}1.23mM$ and $18.12{\pm}0.20s^{-1}$, respectively. Moreover, the plot of initial velocity versus D-serine concentration at fixed L-serine concentrations showed a non-linear hyperbola decay shape and exhibited a competitive inhibition for D-serine with an apparent $K_i$ value of $30.46{\pm}5.93mM$ and with no change in the $k_{cat}$ value. These results provide insightful biochemical information regarding the catalytic properties and the substrate specificity of MtLSD.

• Microbiology and Biotechnology Letters
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• v.43 no.3
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• pp.259-266
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• 2015

Observed trends in climate change, globalization and an aging population have an effect on public health conditions in Korea, prompting a reevaluation of current environmental regulations. In this study, we evaluated the performance of the total coliform (TC) standard, which is the only microbiological standard in the current regulation regime for hot spring water, by estimating correlation with the presence/absence of Legionella, a non-fecal opportunistic pathogen with heat-tolerance. Microbiological data in 7 studies that surveyed Legionella in hot spring waters were subjected to meta-analyses with the odds ratio (OR) as the effect size. The presence/absence of Legionella was significantly correlated to TC levels [OR = 3.1(1.5–6.4, 95% CI), p = 0.002]. Due to there being no direct explanation as to the reason for the occurrence of TC, mesophilic fecal bacteria, being coupled with Legionella presence, the mechanism of the correlation between the two kinds of bacteria was further investigated. Legionella presence was more prevalent with a high heterotrophic plate count [HPC; 4.0(2.2–7.2); p < 0.001] and water temperature [4.3(1.4–13.6), p = 0.011] when the temperature range was <40℃. However, it was reverse-correlated with water temperature when the temperature was >50℃ [0.2(0.1–0.4), p < 0.001]. Therefore, bacterial standing crops in hot spring waters appear to be determined by water temperature in general, and this forces TC and Legionella levels be correlated. In accordance with this relationship, HPC rather than TC reflect the levels of non-fecal contamination better. Therefore, employing HPC as the sole microbiological standard, or adding HPC into the current standard of hot spring water assessment, is suggested as a proactive measure to prevent health issues arising from contamination.

• Journal of dental hygiene science
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• v.15 no.2
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• pp.232-237
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• 2015

The water supplied from dental unit water systems (DUWS) in dentistry may be heavily contaminated with bacteria and thus may be a potential source of infection for both practice staff and patients. The aim of this study was to evaluate the level of heterotrophic bacteria and to confirm the presence of opportunistic pathogens from DUWS in student clinical simulation laboratory of college of dentistry. Water samples were collected from 36 ultrasonic scalers in student clinical simulation laboratory. The levels of heterotrophic bacteria in water samples were quantified by counting colony forming units (CFUs) on R2A agar media. In addition, opportunistic pathogens were detected by using the polymerase chain reaction (PCR) method. The mean CFUs were 16,095 CFU/ml for water samples and all of water samples exceeded current American Dental Association recommendations of 200 CFU/ml. Pseudomonas species and non-tuberculous Mycobacterium species were detected in the one sample and two samples, respectively, among the 36 water samples by the PCR with specific primers for these bacteria. Our study indicated that DUWS in student clinical simulation laboratory can cause potential infection in students and participants. This study suggested the dental unit water line management and wearing personal protective equipment in student clinical simulation laboratory will be needed to reduce bacterial contamination.

• Journal of Periodontal and Implant Science
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• v.37 no.sup2
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• pp.297-310
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• 2007

치조골 흡수는 파골세포와 matrix metalloproteinases (MMPs)에 의한 골의 무기질과 유기질의 파괴로 일어나는 과정이다. 세균성 산물, 주로 내독소는 치은조직 내에서 염증세포의 유주, 사이토카인 생산, 조직파괴 효소 분비 및 파골세포 활성 등의 국소 면역반응을 유도한다. A. actinomycetemcomitans는 급진성 치주염의 원인 균주중 하나로 그 내독소는 치조골의 흡수와 관련된다. MMP-13은 세균성 산물이나 염증성 사이토카인의 자극에 의해 분비되며, 최근의 연구 결과들은 MMP-13이 치주질환의 진행과 골 흡수 과정에서 일정한 역할을 담당하는 것으로 보고하고 있으나, A. actinomycetemcomitans 내독소와 MMP-13과의 관련성에 대한 연구는 미미하다. 이에 이번 연구에서는 A. actinomycetemcomitans 내독소에 의한 MMP-13의 발현과 파골세포 형성을 세포배양을 통하여 관찰하였고, 백서 구개부 치은에 A. actinomycetemcomitans 내독소를 주입하여 흡수가 진행되고 있는 치조골에서 파골세포의 분화와 MMP-13의 발현을 TRAP 염색, 면역조직화학적 방법 등을 통해 관찰하여 다음과 같은 결과를 얻었다. MMP-13 mPNA의 발현은 A. actinomycetemcomitans 내독소 (1ug/ml)로 24시간 자극한 마우스 치주인대 섬유모세포에서 생리식염수로 자극한 세포에 비하여 약 2.6배 증가하였으며 마우스 대식세포에서는 TRAP 양성 세포가 대조군보다 더 많이 나타났다. A. actinomycetemcomitans 내독소를 주입한 백서 치주조직에서는 대조군보다 더 심한 골소실을 보였다. TRAP-양성 다핵 파골세포 유사세포는 치주염군과 대조군 모두 치조골에서 관찰되었다. TRAP-양성 다핵 파골세포 유사세포는 치주염군에서 대조군보다 유의하게 많은 숫자가 관찰되었으며, 치주염군에서 대조군보다 유의하게 많은 숫자가 관찰되었다. MMP-13 면역양성 반응은 치주염군에서 거친 골연을 갖는 치조골상에 배열된 조골세포와 그 인접한 치주인대에서 관찰되었으며 대조군에서는 MMP-13 면역 양성 반응이 치조골 표면에서만 일부 관찰되었다. 이상의 결과는 A. actinomycetemcomitans 내독속가 MMP-13의 발현을 증가시키며 파골세포의 활성을 통하여 치조골의 흡수를 유도함을 시사한다. 또한 A. actinomycetemcomitans 내독소 투여에 의한 실험적 모델은 백서에서 중등도의 골 소실을 동반한 만성 치주염 모델로 향후 치주질환 치료제의 효과를 평가하는데 유용하게 사용될 수 있으리라 기대된다.

• Journal of Practical Agriculture & Fisheries Research
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• v.26 no.3
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• pp.23-31
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• 2024

This study aimed to establish a liquid fermentation process to increase the alcohol productivity of distilled soju using domestically grown sorghum. After preparing mash with different ratios of sorghum and rice, the optimal amount of raw material was determined, and sorghum pretreatment methods, enzyme types, and modified nuruk were tested. The soluble solids (°Brix) of the saccharification solution ranged from 3.00 to 25.20 for bacterial α-amylase and 4.20 to 20.80 for fungal α-amylase. Bacterial α-amylase was more suitable for starch saccharification. At 20% sorghum and 80% rice mash, the alcohol content was 15.11%, showing that soluble solids and alcohol content increased with higher rice content. When puffed sorghum was used with bacterial α-amylase, alcohol content rose to 16.55%, showing puffed sorghum is suitable for fermentation without a separate saccharification process. In mash with 20% puffed sorghum and 80% rice, adding modified nuruk resulted in alcohol contents of 16.73% and 16.28%, respectively, for groups with and without nuruk. The alcohol content of the distillate after vacuum distillation showed a similar trend, suggesting modified nuruk has little effect on alcohol productivity and requires further research. When modified nuruk was added, alcohol and esters increased, but sulfur compounds, which are perceived as off-odors, also rose. Therefore, it is better not to use modified nuruk in distilled soju made with sorghum. In conclusion, the process using 20% puffed sorghum, 80% rice, and bacterial α-amylase is deemed feasible for improving the productivity of distilled soju through liquid fermentation with puffed sorghum and enzymes.

• Korean Journal of Microbiology
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• v.51 no.3
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• pp.209-220
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• 2015

In this study, gut bacterial communities in xylophagous insects were analyzed using the pyrosequencing of 16S rRNA genes for their potential biotechnological applications in lignocelluloses degradation. The result showed that operational taxonomic units (OTUs), species richness and diversity index were higher in the hindgut than in the midgut of all insect samples analyzed. The dominant phyla or classes were Firmicutes (54.0%), Bacteroidetes (14.5%), ${\gamma}-Proteobacteria$ (12.3%) in all xylophagous insects except for Rhinotermitidae. The principal coordinates analysis (PCoA) showed that the bacterial community structure mostly clustered according to phylogeny of hosts rather than their habitats. In our study, the two carboxymethyl cellulose (CMC)-degrading isolates which showed the highest enzyme activity were most closely related to Bacillus toyonensis $BCT-7112^T$ and Lactococcus lactis subsp. hordniae $NCDO\;2181^T$, respectively. Cellulolytic enzyme activity analysis showed that ${\beta}-1,4-glucosidase$, ${\beta}-1,4-endoglucanase$ and ${\beta}-1,4-xylanase$ were higher in the hindgut of Cerambycidae. The results demonstrate that xylophagous insect guts harbor diverse gut bacteria, including valuable cellulolytic bacteria, which could be used for various biotechnological applications.