• 미생물학회지
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• 제53권1호
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• pp.29-38
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• 2017

본 연구에서는 토판염전 결정지에 서식하는 세균군집의 계통학적 다양성을 분석하고 culturomics법에 기반하여 고도 호염균의 다양성을 확보하고자 하였다. 토판염전 내 세균밀도를 조사한 결과, 직접검경법에 의한 생균수는 평판배양법에 비해 $10^3{\sim}10^4$ 배 이상 높은 계수치를 나타내어 배양이 곤란한 세균(viable but non-culturable bacteria, VBNC)이 다수 존재해 있음으로 판단되었다. 토판염전 결정지 내 세균군집 다양성 해석을 위해 배양비의존적 방법인 pyrosequencing 분자기법을 이용하였다. 세균군집의 경우 1,778 OTUs, 다양성 지수 6.16로 나타났으며, 18문46강85목140과 243속으로 확인되었다. Archaea군집은 643 OTUs, 다양성 지수 4.95로 3문6강7목7과 38속이 분포해 있음이 확인되었다. 고도 호염균 생육에 적합한 배양배지 및 배양조건을 고려한 총 59가지의 다양한 배양 방법을 이용하여 137균주를 순수 분리하였다. 분리된 고도호염균의 16S rRNA 유전자 분석결과, 총4문11속의 다양한 계통군으로 확인되었으며 호염성 archaea 계통군 Haloterrigena 속과 haloferax 속이 culturomics법을 통해 성공적으로 분리되었다. 고도 호염균 다양성 확보를 위해 culturomics법이 매우 효과적임을 밝혔다.

• 한국식품저장유통학회지
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• 제12권3호
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• pp.263-266
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• 2005

전남 목포시의 각 가정에서 담근 물김치에서 총 24균주의 유산균을 분리하였다. 이들 분리 유산균 중 5균주가 인공 위액에서 내성을 나타내었다. 이들 유산균은 Lactobacillus plantarum으로 동정하였고, 특히 물김치로부터 동정된 유산균 MUL-2, MUL-4, MUL-18은 인공위액에서 3시간 배양 후에도 초기 생균수에 비해 변화가 거의 없어 가장 강한 내성을 나타내었다. 이들 분리 유산균은 병원성 미생물인 Listeria monocytogenes, Escherichia coli, Staphyrococcus aureus, Vibrio parahaemolyticus, Samonella typhimurium에 대해 뚜렷한 항미생물활성을 나타내었다.

• Journal of Microbiology and Biotechnology
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• 제18권9호
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• pp.1518-1521
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• 2008

Bacteria sense their population density and coordinate the expression of target genes, including virulence factors in Gram-negative bacteria, by the N-acylhomoserine lactones (AHLs)-dependent quorum sensing (QS) mechanism. In contrast, several soil bacteria are able to interfere with QS by enzymatic degradation of AHLs, referred to as quorum quenching. A potent AHL-degrading enzyme, AiiA, from Bacillus thuringiensis has been reported to effectively attenuate the virulence of bacteria by quorum quenching. However, little is known about the role of AiiA in B. thuringiensis itself. In the present study, an aiiA-defective mutant was generated to investigate the role of AHA in rhizosphere competence in the root system of pepper. The aiiA mutant showed no detectable AHL￢-egrading activity and was less effective for suppression of soft-rot symptom caused by Erwinia carotovora on the potato slice. On the pepper root, the survival rate of the aiiA mutant significantly decreased over time compared with that of wild type. Interestingly, viable cell count analysis revealed that the bacterial number and composition of E. carotovora were not different between treatments of wild type and the aiiA mutant. These results provide evidence that AHA can play an important role in rhizosphere competentce of B. thuringiensis and bacterial quorum quenching to Gram-negative bacteria without changing bacterial number or composition.

• 한국환경보건학회지
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• 제37권2호
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• pp.133-140
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• 2011

Antimicrobial activity and bactericidal activity of Caesalpinia sappan L. extracts were investigated against five food-borne pathogens, E. coli, S. aureus, S. typhimurium, B. cereus and L. monocytogenes. Methanol extract of Caesalpinia sappan L. revealed antimicrobial activities against five pathogens. In particular, by paper disc diffusion the highest activity was shown against L. monocytogenes. Antimicrobial activities of methanol extracts showed the most potent activities, but hexane fraction had no activity. Fractions of ethyl acetate and butanol turned out to have higher antimicrobial activities against Gram(+) bacteria than Gram(-) bacteria. The minimum inhibitory concentration against five food-borne pathogens was 1.563 mg/ml on Gram(+) bacteria and 3.125 mg/ml on Gram(-) bacteria. The result of antimicrobial activity in a shaking flask method showed that bacterial growth rate fell by more than 99.999% at 3.125 mg/ml of methanol extract. The highest rate of viable reduction (99.998%) was shown at 0.781 mg/ml of methanol extract against L. monocytogenes. After five minutes of reaction between test strains and methanol extracts, the growth rates of five kinds of bacteria were reduced by more than 99.999% at a concentration of 100 mg/ml. Therefore, it is suggested that methanol extracts of Caesalpinia sappan L. can be developed as a natural sanitizer or disinfectant.

• 한국수산과학회지
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• 제45권6호
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• pp.600-605
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• 2012

In this study, we investigated the mechanism of inhibition of pathogenic bacteria by Pediococcus pentosaceus strain SH-10 isolated from hard Clam Meretrix meretrix sikhae. When P. pentosaceus SH-10 was co-cultured in MRS broth with pathogenic bacteria, including Bacillus cereus, Listeria monocytogenes, Salmonella choleraesuis and Staphyloccus aureus, no viable pathogenic cells were detected after 18 h of incubation. However, pediocin or a pediocin-like bacteriocin was not detected in cultures of P. pentosaceus SH-10 by the agar diffusion method. Organic acids were produced in MRS broth in proportion to the incubation time of P. pentosaceus SH-10. These results indicate that P. pentosaceus SH-10 inhibited the growth of pathogenic bacteria by lowering the pH of the growth medium through the production of organic acids, including sodium lactate, sodium acetate, and sodium citrate.

• 한국미생물·생명공학회지
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• 제23권4호
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• pp.373-377
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• 1995

We investigated the survival, $\beta$-galactosidase activity and cellular permeability of lactic acid bacteria such as Lactobacillus acidophilus ATCC 4356, Lactobacillus casei subsp. casei IFO 3533, Streptococcus thermophilus KCTC 2185, Lactobacillus delbrueckii subsp. lactis ATCC 4797, and Lactobacillus delbrueckii subsp. bulgaricus ATCC 11842 in anaerobic condition of pH 1.5-3.5 range. Numbers of all tested viable cells did not decrease at pH 3.5, but decreased rapidly at pH 1.5 and pH 2.5 during 2 hour incubation at modified EG medium. Immediately after 2 hour incubation, the decrease in population at pH 1.5 and pH 2.5 was about 6-8 and 5-7 log cycles/ml, respectively. Lactobacillus acidophilus ATCC 4356 showed the higest survival of all tested bacteria. The $\beta$-galactosidase activity from Lactobacillus delbrueckii subsp. bulgaricus ATCC 11842 and Streptococcus thermophilus KCTC 2185 decreased rapidly at pH 1.5 and 2.5, but there was a little decrease at pH 3.5. The cellular permeability that was measured by the leakage of intracellular materials increased with decrease of pH. These results suggest that the ingested lactic acid bacteria may be destroyed in contact with low pH of gastric acid.

• 한국임상수의학회지
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• 제24권2호
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• pp.125-129
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• 2007

Artemisia capillaris THUNB is a perennial herb that belongs to the family Compositae spp and the most common plant among the various herbal folk remedies used in treatment of abdominal pain, hepatitis, chronic liver disease, jaundice and coughing in Korea. This experiment was conducted to investigate the inhibitory effects of orally administrated Artemisia capillaris extracts on the pathogenic bacteria in 200 ICR mice. The experimental groups showed inhibitory effects on the bacteria in $1{\sim}3$ days after inoculation. After 21 days of inoculation, no viable bacterial cells appeared in the feces of both experimental groups while they did appear in the control group. The results of these studies indicate Artemisia capillaris extract exhibited excellent antimicrobial and inhibitory effects on the food poisoning pathogenic bacteria; S. enteritidis, E. coli O157:H7, L. monocytogenes and S. aureus.

• 한국축산식품학회지
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• 제20권1호
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• pp.56-63
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• 2000

This study was investigated the effects of the addition of adlay with levels of 1%(T1), 2%(T2), 3%(T3) and 4% (T4) in skim milk substrate on the physicochemical and microbiological properties of yoghurt during fermentation and storage period at 4$\pm$1$^{\circ}C$. Adlay yoghurt were fermented with the mixed cultures of YC-380, ABT-4 and ABT-D. Titratable acidity and pH values of all treatments were increased and decreased significantly(p<0.05) with fermentation period, respectively and increased and decreased slightly during the storage period, respectively. There were increased and decreased in order of all treatments fermented with YC-380, ABT-4 and ABT-D. Viscosity of adlay yoghurt increased rapidly in order of T4, T3, T2 and T1 during fermentation and slowly in order of T1, T2, T3 and T4 during the storage period. There were increased in order of all treatments fermented with ABT-D, YC-380 and ABT-4. The counts of viable cells of lactic acid bacteria in all treatments were rapidly and slightly increased during fermentation and storage period, respectively. There were increased in order of fermented with ABT-D, ABT-4 and YC-380 in all treatments. The counts of E. coli were not found in adlay yoghurt. In all treatments, T1 showed slightly high compared to that of control. Based on the results of this experiment, the optimum level of addition of adlay were 1% (w/v) for production of acid production, pH, viscosity and the counts of viable cells of lactic acid bacteria.

• Journal of Periodontal and Implant Science
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• 제48권3호
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• pp.164-173
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• 2018

Purpose: The aim of this study was to evaluate the antimicrobial effect of a newly devised toothbrush with light-emitting diodes (LEDs) on Porphyromonas gingivalis attached to sandblasted and acid-etched titanium surfaces. Methods: The study included a control group, a commercial photodynamic therapy (PDT) group, and 3 test groups (B, BL, and BLE). The disks in the PDT group were placed in methylene blue and then irradiated with a diode laser. The B disks were only brushed, the BL disks were brushed with an LED toothbrush, and the BLE disks were placed into erythrosine and then brushed with an LED toothbrush. After the different treatments, bacteria were detached from the disks and spread on selective agar. The number of viable bacteria and percentage of bacterial reduction were determined from colony counts. Scanning electron microscopy was performed to visualize bacterial alterations. Results: The number of viable bacteria in the BLE group was significantly lower than that in the other groups (P<0.05). Scanning electron microscopy showed that bacterial cell walls were intact in the control and B groups, but changed after commercial PDT and LED exposure. Conclusions: The findings suggest that an LED toothbrush with erythrosine treatment was more effective than a commercial PDT kit in reducing the number of P. gingivalis cells attached to surface-modified titanium in vitro.

• Journal of Animal Science and Technology
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• 제58권4호
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• pp.16.1-16.7
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• 2016

Background: This study was conducted to examine the quality and storage characteristics of yogurt containing antifungal-active lactic acid bacteria (ALH, Lacobacillus sakei ALI033) isolated from kimchi and cinnamon ethanol extract. The starter was used for culture inoculation (1.0 % commercial starter culture YF-L812 and ALH). Results: The antifungal activity of cinnamon extracts was observed in treatments with either cinnamon ethanol extracts or cinnamon methanol extracts. Changes in fermented milk made with ALH and cinnamon extract during fermentation at $40^{\circ}C$ were as follows. The pH was 4.6 after only 6 h of fermentation. Titratable acidity values were maintained at 0.8 % in all treatment groups. Viable cell counts were maintained at $4{\times}10^9CFU/mL$ in all groups except for 1.00 % cinnamon treatment. Sensory evaluations of fermented milk sample made with ALH and 0.05 % cinnamon ethanol extract were the highest. Changes in fermented milk made with ALH and cinnamon ethanol extract during storage at $4^{\circ}C$ for 28 days were as follows. In fermented milk containing ALH and cinnamon ethanol extracts, the changes in pH and titratable acidity were moderate and smaller compared with those of the control. Viable cell counts were maintained within a proper range of $10^8CFU/mL$. Conclusions: The results of this study suggest that the overgrowth of fermentation strains or post acidification during storage can be effectively delayed, thereby maintaining the storage quality of yogurt products in a stable way, using cinnamon ethanol extract, which exhibits excellent antifungal and antibacterial activity, in combination with lactic acid bacteria isolated from kimchi.