• 한국어병학회지
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• 제3권1호
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• pp.11-19
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• 1990

방어의 유결절증(類結節症) 신속진단(迅速診斷)을 위(爲)한 면역형광항체법(免疫螢光抗體法)의 유용성(有用性)을 검토(檢討)하기 위하여 원인균(原因菌)으로 면역(免疫)된 항혈청(抗血淸)에서 면역(免疫)글로브린 G(IgG)를 분리(分離)하여 FITC표식(標識) 항체(抗體)를 정제(精製)하였다. 정제(精製)된 표식항체(標識抗體)는 형광강도(螢光强度)가 1 : 32였으며 이 표식항체(標識抗體)를 이용(利用)하여 1990년(年) 7월(月)부터 10월(月)까지 경남(慶南) 통영군(統營郡) 소재(所在) 방어 양식장(養殖場)을 대상(對象)으로 유결절증진단시험(類結節症診斷試驗)을 실시(實施)한 결과(結果) 직접형광항체법(直接螢光抗體法)으로 2시간내(時間內)에 원인균(原因菌)의 신속진단(迅速診斷)이 가능(可能)하고 균검출면(菌檢出面)에서도 평판도말(平板塗抹) 배양법(培養法)보다 효과적(效科的)인 것으로 나타났다.

• 상하수도학회지
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• 제23권2호
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• pp.199-205
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• 2009

It is very important to differentiate of DNA derived from live or dead bacteria within mixed microbial communities in aquatic environments. Ethidium monoazide (EMA) is a DNA intercalating agent and the treatment of EMA with strong visible light cleaves the genomic DNA of bacteria. In dead bacterial cells, EMA intercalates into the genomic DNA, induces the cleavage of DNA, and inhibits the PCR amplification. In this study, we developed the EMA-PCR and EMA real-time PCR to detect the DNA derived from viable Escherichia coli (E.coli) in mixed cultures of live and dead E.coli. The treatment of EMA, $50{\mu}g/mL$, and 650 W visible halogen light exposure for 2 minutes cleaved the genomic DNA derived from heat killed E.coli but did not those of live E.coli. EMA-PCR could detect the DNA from live E.coli in mixed culture samples of live and dead E.coli at various ratio and there was no DNA amplification in only dead E.coli cultures. Similar results were observed in EMA real-time PCR. Further studies are needed to develop various EMA-PCR methods to detect viable waterborne pathogens such as Helicobacter pylori, Giardia lamblia, and so on.

• Journal of Microbiology and Biotechnology
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• 제31권7호
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• pp.999-1010
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• 2021

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in the environment. They are highly toxigenic and carcinogenic. Probiotic bacteria isolated from fermented foods were tested to check their ability to degrade and/or detoxify PAHs. Five probiotic bacteria with distinct morphologies were isolated from a mixture of 26 fermented foods co-cultured with benzo(a)pyrene (BaP) containing Bushnell Haas minimal broth. Among them, B. velezensis (PMC10) significantly reduced the abundance of BaP in the broth. PMC10 completely degraded BaP presented at a lower concentration in broth culture. B. velezensis also showed a clear zone of degradation on a BaP-coated Bushnell Haas agar plate. Gene expression profiling showed significant increases of PAH ring-hydroxylating dioxygenases and 4-hydroxybenzoate 3-monooxygenase genes in B. velezensis in response to BaP treatment. In addtion, both live and heat-killed B. velezensis removed BaP and naphthalene (Nap) from phosphate buffer solution. Live B. velezensis did not show any cytotoxicity to macrophage or human dermal fibroblast cells. Live-cell and cell-free supernatant of B. velezensis showed potential anti-inflammatory effects. Cell-free supernatant and extract of B. velezensis also showed free radical scavenging effects. These results highlight the prospective ability of B. velezensis to biodegrade and remove toxic PAHs from the human body and suggest that the biodegradation of BaP might be regulated by ring-hydroxylating dioxygenase-initiated metabolic pathway.

• 대한소아치과학회지
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• 제43권3호
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• pp.306-312
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• 2016

치아우식은 Streptococcus mutans와 S. sobrinus가 주요 원인균이며, 이를 예방하기 위해서 구강 청결제를 사용한다. 그러나 구강청결제의 부작용 및 해로움으로 인하여 소아에게 권장하기에 주위를 요한다. 전기 분해수는 물을 전극을 통해서 전류를 흘려주어 생성되는 용액으로 항균력을 갖는다. 본 연구에서는 전기 분해수를 구강 청결제 대용으로 사용하기 위해서 치아 우식원성 세균 및 바이오 필름에 대한 항균력을 조사하였다. 염화나트륨이 포함된 증류수를 백금전극을 이용하여 전기 분해수를 생성하였다. 전기분해 수소수의 물리화학적 성분을 분석하고 S. mutans 및 S. sobrinus 배양액을 원심분리하여 세균을 얻고 전기 분해수, 알코올 및 불소가 포함된 구강 청결제를 처리하고 살아있는 세균 수를 배양을 통해서 조사하였다. 또한 치아우식균의 바이오 필름을 형성시킨 후, 전기 분해수 및 구강 청결제를 처리하여 바이오 필름 제거능을 크리스탈 바이올렛 염색을 이용하여 분석하고, 바이오 필름 내 살아있는 세균수의 양은 배양을 통하여 분석하였다. 전기분해수는 높은 농도의 자유염소 (free chlorine)을 포함하고 중성 페하를 보였다. 전기 분해수는 유의하게 S. mutans 및 S. sobrinus에 대해서 항균력을 보였으며, 이 세균들의 바이오 필름 제거능 및 바이오 필름 내 세균에 대해서도 항균력을 보였다. 전기 분해수는 부유세균에 대해서 알코올이 포함된 구강청결제보다 약한 항균력을 보였지만, 바이오 필름 세균에 대해서는 더 강한 항균력을 나타냈다. 이러한 결과를 바탕으로 중성 전기 분해수는 치아우식 예방을 위한 기존 구강 청결제의 대체 용액으로 사용이 가능할 것으로 사료된다.

• Journal of Dairy Science and Biotechnology
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• 제35권1호
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• pp.55-72
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• 2017

The second article of 'Effects of heat treatment on the nutritional quality of milk,' titled 'Destruction of microorganisms in milk by heat treatment' and authored by Dr. Seong Kwan Cha, who worked at the Korea Food Research Institute, covers the heat-stable microorganisms that exist in milk after pasteurization. The article focusses on the microbiological quality of raw milk and market milk following heat treatment, and is divided into four sub-topics: microbiological quality of raw milk, survey and measurement of microorganisms killed in raw milk, effect on psychrophilic and mesophilic microorganisms, and effect of heat treatment methods on thermoduric microorganisms. Bacillus spp. and Clostridium spp. are sporeforming gram-positive organisms commonly found in soil, vegetables, grains, and raw and pasteurized milk that can survive most food processing methods. Since spores cannot be inactivated by LTLT (low temperature long time) or HTST (high temperature short time) milk pasteurization methods, they are often responsible for food poisoning. However, UHT (ultra high temperature) processing completely kills the spores in raw milk by heating it to temperatures above $130^{\circ}C$ for a few seconds, and thus, the UHT method is popularly used for milk processing worldwide.

• Journal of Microbiology and Biotechnology
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• 제8권6호
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• pp.588-594
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• 1998

Lactic acid bacteria were isolated from Kimchi and screened for bacteriocin production. Strain SE1, identified as Lactobacillus curvatus sp., showed the strongest inhibitory activity against Lactobacillus delbrueckii subsp. delbrueckii. The bacteriocin was inactivated by amyloglucosidase, trypsin, or protease K treatment. However, it maintained its activity under heat treatment at $100^{\circ}C$ for 60 min. The production of the bacteriocin had a growth-related mode and decreased around the early-stationary phase. The optimum temperature for the growth of L. curvatus SE1 was $37^{\circ}C$; however, the optimum temperature for bacteriocin production was $30^{\circ}C$. The bacteriocin activity was decreased by treatment with methanol, butanol, acetone, or chloroform, however, it was not affected by treatment with ethanol, iso-propanol, or cyclohexane. The inhibitory activity of bacteriocin was stable over a wide range of pHs (2 to 11). The bacteriocin from L. curvatus SE1 killed the indicator strain by a bactericidal mode of action. The bacteriocin from L. curvatus SE1 was partially purified by ethanol precipitation and ion exchange chromatography. SDS-polyacrylamide gel electrophoresis was used to determine the molecular weight of the bacteriocin by the bacteriocin activity test. The apparent molecular mass of the bacteriocin produced by L. curvatus SE1 was about 14 kDa.

• 한국수소및신에너지학회논문집
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• 제24권2호
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• pp.99-106
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• 2013

The variations of performance and metabolites at an early stage were investigated for the successful start-up technology in continuous fermentative hydrogen production. Unsuccessful start-up was observed when the operation mode was changed from batch to continuous mode after the yield was reached to 0.5 mol $H_2$/mol $hexose_{added}$ by batch mode. $H_2$ production continued till 12 hours accompanied by butyrate production, but did not last with propionate production increase. It was suspected that the failure was due to the regrowth of propionic acid bacteria during batch mode which were inhibited by heat-shock but not completely killed. Thus, successful start-up was tried by early switchover from batch to continuous operation; continuous operation was started after the $H_2$ yield was reached to 0.2 mol $H_2$/mol $hexose_{added}$ by batch mode. Although $H_2$ production rate decreased at an early stage, stable $H_2$ yield of 0.8 mol $H_2$/mol $hexose_{added}$ was achieved after 10 days by lowering down propionate production. And it was also concluded that the reason for $H_2$ production decrease at an early stage was due to alcohol production by self detoxification mechanism against VFAs accumulation.

• ALGAE
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• 제25권2호
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• pp.99-104
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• 2010

A psychrotolerant cyanobacterium, Nodularia spumigena KNUA005, was isolated from a cyanobacterial bloom sample collected near Dasan Station in Ny-${\AA}lesund$, Svalbard Islands during the Arctic summer season. To generate an axenic culture, the isolate was subjected to three purification steps: centrifugation, antibiotic treatment and streaking. The broad antibacterial spectrum of imipenem killed a wide range of heterotrophic bacteria, while the cyanobacterium was capable of enduring both antibiotics, the remaining contaminants that survived after treatment with imipenem were eliminated by the application of an aminoglycoside antibiotic, kanamycin. Physical separation by centrifugation and streaking techniques also aided axenic culture production. According to the cold-tolerance test, this mat-forming cyanobacterium was able to proliferate at low temperatures ranging between 15 and $20^{\circ}C$ which indicates the presence of cold-tolerance related genes in N. spumigena KNUA005. This suggests the possibility of incorporating cold-resistance genes into indigenous cyanobacterial strains for the consistent production of algae-based biofuel during the low-temperature seasons. Therefore, it is needed to determine the cold-tolerance mechanisms in the Arctic cyanobacterium in the next research stage.

• International Journal of Oral Biology
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• 제41권2호
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• pp.75-81
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• 2016

Human mouth environment is known to include a variety bacteria, including Streptococcus spp., Staphylococcus spp., Actinomyces spp., Lactobacillus spp., Candida spp., Enterobacteriaceae, et al. Human oral microorganisms can cause dental caries, gingivitis, periodontitis, respiratory tract infection, and cardiovascular disease. Thus, right denture cleaning is essential to oral and general human health. The aim of this study was to evaluate the bactericidal effect of a sodium dichloroisocyanurate-based effervescent tablet (Aos Denti Germ, Aos Company, Chungbuk, Korea) against oral microorganisms. A total of 5 species Streptococcus spp. (Streptococcus anginosus, Streptococcus mitis, Streptococcus mutans, Streptococcus oralis, and Streptococcus sobrinus), Actinomyces oris, Candida albicans, and Escherichia coli were used in this study. All strains were exposed to the distilled water prepared with effervescent tablet. After the exposure, the mixture of strains and effervescent tablet was inoculated onto blood agar or MacConkey agar plate and cultured at $36^{\circ}C$. All strains were killed immediately on exposure to effervescent tablet. The results suggested that effervescent tablet could be used as an effective denture cleanser for dental hygiene.

• 대한수의학회지
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• 제24권1호
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• pp.58-63
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• 1984

Fecal material from cattle, which was confirmed to be infected with Johne's disease by clinical and pathological symptoms, was decontaminated with 4% NaOH and inoculated into the $L{\ddot{o}}wenstein$-Jensen media supplemented with 1% of heat-killed Mycobacterium bovis. After 2-4 week-incubation at $37^{\circ}C$, typical acid-fast mycobacteria was isolated. With the results of staining properties, morphological characteristics, the requirement of mycobactin for growth and the other biochemical properties, isolated mycobacteria was identified as Mycobacterium paratuberculosis. Female guinea pigs were sensitized with the isolates, and skin test was done with purified protein derivatives (PPDs) of M. avium, M. bovis and M. paratuberculosis 4 weeks after sensitization. Animals showed the largest reaction to the PPDs of M. avium and M. paratuverculosis.