• Journal of Korean Academy of Oral Health
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• 제41권4호
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• pp.290-295
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• 2017

Objectives: Dental plaque emits red fluorescence under a visible blue light near the ultra-violet end of the light spectrum. The fluorescence characteristics of each microorganism have been reported in several studies. The aim of this study was to evaluate changes in red fluorescence of oral microorganisms that is affected by blood in the culture media. Methods: The gram-positive Actinomyces naeslundii (AN, KCTC 5525) and Lactobacillus casei (LC, KCTC 3109) and gram negative Prevotella intermedia (PI, KCTC 3692) that are known to emit red fluorescence were used in this study. Each bacterium was activated in broth and cultivated in different agar media at $37^{\circ}C$ for 7 days. Tryptic soy agar with hemin and vitamin $K_3$ (TSA), TSA with sheep blood (TSAB), basal medium mucin (BMM) medium, and BMM with sheep blood (BMMB) were used in this study. Fluorescence due to bacterial growth was observed under 405-nm wavelength blue light using the quantitative light-induced fluorescence-digital (QLF-D) device. The red, green, and blue fluorescence values of colonies were obtained using image-analysis software and the red to green ratio (R/G value) and red to total RGB ratio (R/RGB value) were calculated for quantitative comparison. Results: The QLF-D images of the AN, LC, and PI colonies showed red fluorescence in all media, but the fluorescence of all bacteria was reduced in TSA and BMM media, compared with in TSAB and BMMB media. Both the R/G and the R/RGB values of all bacteria were significantly reduced in growth media without blood (P<0.001). Conclusions: Based on this in vitro study, it can be concluded that red fluorescence of oral bacteria can be affected by growth components, especially blood. Blood-containing medium could be a significant factor influencing red fluorescence of oral bacteria. It can be further hypothesized that bleeding in the oral cavity can increase the red fluorescence of dental plaque.

• Journal of Microbiology and Biotechnology
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• 제27권8호
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• pp.1409-1418
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• 2017

Two typical microbial communities from Chinese rice wine fermentation collected in Yichang city and Suzhou city in China were investigated. Both communities could ferment glutinous rice to rice wine in 2 days. The sugar and ethanol contents were 198.67 and 14.47 mg/g, respectively, for rice wine from Yichang city, and 292.50 and 12.31 mg/g, respectively, for rice wine from Suzhou city. Acetic acid and lactic acid were the most abundant organic acids. Abundant fungi and bacteria were detected in both communities by high-throughput sequencing. Saccharomycopsis fibuligera and Rhizopus oryzae were the dominant fungi in rice wine from Suzhou city, compared with R. oryzae, Wickerhamomyces anomalus, Saccharomyces cerevisiae, Mucor indicus, and Rhizopus microsporus in rice wine from Yichang city. Bacterial diversity was greater than fungal diversity in both communities. Citrobacter was the most abundant genus. Furthermore, Exiguobacterium, Aeromonas, Acinetobacter, Pseudomonas, Enterobacter, Bacillus, and Lactococcus were highly abundant in both communities.

• 한국지역사회생활과학회지
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• 제18권2호
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• pp.241-246
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• 2007

This study was conducted to select and screen for an antifungal bacterial strain showing pathogen inhibitory activity against Diaporthe actinidiae, which causes stem-end rot in kiwi fruit. Four bacterial strains were isolated which strongly inhibit Diaporthe actinidiae from among two hundred and fifty bacterial strains screened from the soil where kiwi fruit were grown. By co-culturing bacterial strain #72 and the pathogen causing the stem-end rot of kiwi fruit, bacterial strain #72 showed 81.0% antifungal activity against Diaporthe actinidiae. Bacterial strain #72 was identified to be from the genus Bacillus sp. based on morphological and biochemical characterization. The bacterialization of culture broth for Bacillus sp. #72 which was sterilized at $121^{\circ}C$ for 15 minutes and than purified by $0.45{\mu}m$ membrane filter showed almost all of the antagonistic activity against Diaporthe actinidiae. We have also confirmed that in vitro treatment of Bacillus sp. #72 cultured in SD+B+P(sugar 5%, soy sauce 3%, beef extract 0.2%, peptone 0.2%) medium efficiently inhibited the growth of Diaporthe actinidiae responsible for stem-end rot in kiwi fruit.

• 한국지역사회생활과학회지
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• 제21권3호
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• pp.311-322
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• 2010

The purpose of this study was to examine food hygiene knowledge and health practice levels of elementary school students at foodservice in the Suwon area. Of the 500 upper graders from three elementary schools, 486 students (97.2%) participated in the study. The questionnaire was composed of general characteristics including experience of serving food at school, food hygiene knowledge (25 questions), and health practice (18 questions). The results were as follows: The education experiences of food hygiene were below 40% though most students (88.1%) participated in providing food at foodservice. The percentage of correct answers in food hygiene knowledge was over 70% in most questions, but relatively lower in food preservation temperature (44.7%) and food poisoning bacteria (43.2%). When we examined food hygiene behavior of elementary school students in 5scales, the level of personal hygiene management was 4.04, sanitary management in food product was 3.62, environmental hygiene was 3.92, and foodborn disease and food microorganism was 3.81. Each level in each subarea was significantly related in the frequency of hygiene education experiences. Finally, the food hygiene knowledge was positively correlated with its behavior level in elementary school foodservice. These results suggested that the knowledge of food hygiene may affect its behavior, and therefore, regular education of food hygiene at home and school would be needed to improve food safety in foodservice.

• 대한환경공학회지
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• 제31권2호
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• pp.139-146
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• 2009

본 연구에서는 두부공장에서 발생된 폐수를 이용한 생물학적 수소생성 특성과 미생물의 군집 변화를 살펴보았다. 두부 폐수는 산 또는 알카리 조건에서 전처리 된 후 수소생성량을 비교 하였으며, 산처리와 열처리를 병행하여 전처리 하였을 때 가장 왕성한 수소생산을 보였으며, Gompartz 방정식을 이용한 수소가스 발생량($P_h$)은 약 661.01 mL이고 최대 수소 생성율($R_h$)은 12.21 mL/g dry wt biomass/hr 이였다. 16S rDNA의 PCR-DGGE 결과 대부분 군집은 Streptococcus sp. 미생물로 규명되었으며 수소생성에 기여도가 큰 미생물은 Streptococcus gallolyticus sub sp.으로 판단되었다.

• 대한환경공학회지
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• 제28권7호
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• pp.757-763
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• 2006

본 연구에서는 BTEX로 오염된 저질로부터 순수 분리한 BTEX를 탄소원으로 $NO_3$-N를 전자수용체로 이용하는 미생물의 오염토양에 대한 현장 적용 가능성을 평가하였다. 이와 함께 주입한 순수 분리 미생물과 토착 미생물과의 상호 관계를 관찰하기 위하여 시간 경과에 따른 오염된 토양에서의 미생물 군집 변화도 관찰하였다. 이를 위해 BTEX로 오염 가능성이 적은 지역으로부터 채취한 토양 시료 100 g에 benzene, toluene, ethylbenzene, o-xylene을 각각 일정량 주입한 후, 동정 분리한 Pseudomonas stutzeri strain 15(DQ 202712):Klebsiella sp. strain 20(DQ 202715):Citrobacter sp. strain A(DQ 202713)를 2;1:1의 비율로 주입하여 BTEX 분해 효율과 미생물 군집 변화를 관찰하였다. 실험결과, $NO_3$-N와 BTEX가 모두 존재하는 조건에서 동정 분리한 미생물에 의한 분해 효율이 가장 높게 관찰되었다. 그리고 PCR-DGGE를 통한 미생물 군집 변화 관찰 결과, 토양 내 존재하는 다양한 미생물들의 peak는 대부분 감소된 반면, 주입한 동정분리 미생물 peak는 증가되는 것을 관찰할 수 있었다. 그러나 주입한 미생물 3종 가운데 Pseudomona stutzeri만이 우점화 된 결과가 관찰되었다.

• 한국환경농학회지
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• 제40권1호
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• pp.49-59
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• 2021

BACKGROUND: Soil salinity causes reduction of crop productivity. Rhizosphere microbes have metabolic capabilities and ability to adaptation of plants to biotic and abiotic stresses. Plant growth-promoting bacteria (PGPB) could play a role as elicitors for inducing tolerance to stresses in plants by affecting resident microorganism in soil. This study was conducted to demonstrate the effect of selected strains on rhizosphere microbial community under salinity stress. METHODS AND RESULTS: The experiments were conducted in tomato plants in pots containing field soil. Bacterial suspension was inoculated into three-week-old tomato plants, one week after inoculation, and -1,000 kPa-balanced salinity stress was imposed. The physiological and biochemical attributes of plant under salt stress were monitored by evaluating pigment, malondialdehyde (MDA), proline, soil pH, electrical conductivity (EC) and ion concentrations. To demonstrate the effect of selected Bacillus strains on rhizosphere microbial community, soil microbial diversity and abundance were evaluated with Illumina MiSeq sequencing, and primer sets of 341F/805R and ITS3/ITS4 were used for bacterial and fungal communities, respectively. As a result, when the bacterial strains were inoculated and then salinity stress was imposed, the inoculation decreases the stress susceptibility including reduction in lipid peroxidation, enhanced pigmentation and proline accumulation which subsequently resulted in better plant growth. However, bacterial inoculations did not affect diversity (observed OTUs, ACE, Chao1 and Shannon) and structure (principle coordinate analysis) of microbial communities under salinity stress. Furthermore, relative abundance in microbial communities had no significant difference between bacterial treated- and untreated-soils under salinity stress. CONCLUSION: Inoculation of Bacillus strains could affect plant responses and soil pH of tomato plants under salinity stress, whereas microbial diversity and abundance had no significant difference by the bacterial treatments. These findings demonstrated that Bacillus strains could alleviate plant's salinity damages by regulating pigments, proline, and MDA contents without significant changes of microbial community in tomato plants, and can be used as effective biostimulators against salinity stress for sustainable agriculture.

• 대한의생명과학회지
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• 제23권2호
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• pp.89-95
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• 2017

Tuberculosis (TB), mainly disseminated by infection of the respiratory tract, remains an unsolved community health problem by Mycobacterium tuberculosis (MTB). However, because of the different susceptibility to MTB, people infected with MTB do not all develop TB. These differences of disease arise from individual genetic susceptibility as well as the property of the microorganisms itself. CD226, one of the genetic factors that influences TB, interact with its ligand PVR and ITGB2. It is induced various cellular responses that contribute multiple innate and adaptive responses. In a previous study, CD226 enhanced immune efficacy induced by Ag85A DNA vaccination that is secreted protein by MTB. The aim of this study was to investigate the association between six genetic polymorphisms of CD226 gene and TB status with Korean population. Our results show that two SNPs of CD226 were identified to associate with tuberculosis. The highest significant SNP was rs17081766 (OR=0.70, CI: 0.54~0.90, $P=5.4{\times}10^{-3}$). According to this study, polymorphisms of CD226 gene affect the outbreak of TB in MTB-infected patients. It is suggested that polymorphism of other genes also associated with immune responses results in susceptibility to TB. The results from this study suggest that not only the characteristics of the microorganism itself but also the genetic background of the individual may affect progression of TB in MTB-infected patients.

• Environmental Engineering Research
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• 제25권1호
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• pp.29-35
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• 2020

The aim of this study was to estimate the microbial metabolic activity of indigenous soil microbes under the radon exposure with different intensity and times in the secured laboratory radon chamber. For this purpose, the soil microbes were collected from radon-contaminated site located in the G county, Korea. Thereafter, their metabolic activity was determined after the radon exposure of varying radon concentrations of 185, 1,400 and 14,000 Bq/㎥. The average depth variable concentrations of soil radon in the radon-contaminated site were 707, 860 and 1,185 Bq/㎥ from 0, 15, and 30 cm in deep, respectively. Simultaneously, the soil microbial culture was mainly composed of Bacillus sp., Brevibacillus sp., Lysinibacillus sp., and Paenibacillus sp. From the radon exposure test, higher or lower radiation intensities compared to the threshold level attributed the metabolic activity of mixed microbial consortium to be reduced, whereas the moderate radiation intensity (i.e. threshold level) induced it to the pinnacle point. It was decided that radon radiation could instigate the microbial metabolic activity depending on the radon levels while they were exposed, which could consequently address that the certain extent of threshold concentration present in the ecosystem relevant to microbial diversity and population density to be more proliferated.

• 한국물환경학회지
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• 제28권2호
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• pp.320-331
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• 2012

A combination system of catch canal and constructed wetland was designed and suggested to improve water quality in gagricultural region of lower Dong-jin river basin. In order to evaluate an water quality improvement efficiency of the designed combination system, the NPS-WET model was applied in this study. Simulation result of the NPS-WET shown that the nutrient load removal rate of constructed wetland was BOD, T-N, T-P and SS was 30.7~39.0%, 46~60%, 40.7~57.0% and 68.2~74.7%, respectively. Nutrients reduction of constructed wetland was higher in growing season than winter season because vital activity of microorganism, macrophyte and algae was augmented with high air and water temperature. Effluents from constructed wetland can affect water-quality of catch canal drains, especially, water-quality on junction point to Dong-jin river. Water-quality improvement in low-flowed catch canal (Un-san) was more significant than in high-flowed catch canal (Won-pyeong). In conclusion, a feasible design of constructed wetland is necessary to treat large quantity of receiving water. The NPS-WET is useful tool for assessing water-quality improvement efficiency using constructed wetland.