• Journal of Microbiology
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• 제44권3호
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• pp.269-275
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• 2006

Atmospheric-pressure cold plasma (APCP) using helium/oxygen was developed and tested as a suitable sterilization method in a clinical environment. The sterilizing effect of this method is not due to UV light, which is known to be the major sterilization factor of APCP, but instead results from the action of reactive oxygen radicals. Escherichia coli, Staphylococcus aureus, and Saccharomyces cerevisiae deposited on a nitrocellulose filter membrane or Bacillus subtilis spores deposited on polypropylene plates were exposed to helium/oxygen plasma generated with AC input power at 10 kHz, 6 kV. After Plasma treatment, nitrocellulose filter membranes were overlaid on fresh solid media and CFUs were counted after incubation overnight. D-values were 18 sec for E. coli, 19 sec for S. aureus, 1 min 55 sec for S. cerevisiae, and 14 min for B. subtilis spores. D-values of bacteria and yeast were dependent on the initial inoculation concentration, while the D-value of B. subtilis spores showed no correlation. When treated cells were observed with a scanning electron microscope, E. coli was more heavily damaged than S. aureus, S. cevevisiae exhibited peeling, and B. subtilis spores exhibited shrunken morphology. Results showed that APCP using helium/oxygen has many advantages as a sterilization method, especially in a clinical environment with conditions such as stable temperature, unlimited sample size, and no harmful gas production.

• 미생물학회지
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• 제29권4호
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• pp.250-257
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• 1991

An obligate methanol-oxidizing bacterium, Methylobacillus sp. strain SK1, which grows only on methanol was isolated from soil. The isolate was nonmotile Gram-negtive rod. It does not have internal membrane system. The colonies were small, whitish-yellow, and smooth. The guanine plus cytosine content of the DNA was 48 mol%. Cellular fatty acids consisted predominantly of large amounts of straight-chain saturated $C_{16:0}$ acid and unsaturated $C_{16:1}$ acid. The major ubiquinone was Q-8, and Q-10 was present as minor component. The cell was obligately aerobic and exhibited catalase, but no oxidase, activity. Poly-.betha.-hydroxybutyrate, endospores, or cysts were not observed. the isolate could grow only on methanol in mineral medium. Growth factors were not required. The isolate was unable to use methane, formaldehyde, formate, methylamine, and several other organic compounds tested as a sole source of carbon and energy. Growth was optimal at 35.deg.C and pH 7.5. It could not grow at 42.deg.C. The doubling time was 1.2h at 30.deg.C when grown with 1.0%(v/v) methanol. The growth was not affected by antibiotics inhibiting cell wall synthesis and carbon monoxide but was completely suppressed by those inhibiting protein synthesis. Methanol was found to be assimilated through the ribulose monophosphate pathway. Cytochromes of b-, c-, and o- types were found. Cell-free extracts contained a phenazine methosulfate-linked methanol dehydrogenase activity, which required ammonium ions as an activator. Cells harvested after the late exponential phase seemed to contain blue protein.ein.

• Journal of Microbiology and Biotechnology
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• 제15권5호
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• pp.984-991
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• 2005

Soil or seed applications of plant growth-promoting rhizobacteria (PGPR) have been used to enhance growth of several crops as well as to suppress the growth of plant pathogens. In this study, we selected a PGPR strain, Paenibacillus polymyxa strain E681, out of 3,197 heat-stable bacterial isolates from winter wheat and barley roots. Strain E681 inhibited growth of a broad spectrum plant pathogenic fungi in vitro, and treatment of cucumber seed with E681 reduced incidence of damping-off disease caused by Pythium ultimum, Rhizoctonia solani, or Fusarium oxysporum. When inoculated onto seeds as vegetative cells or as endospores, E681 colonized whole cucumber root systems and root tips. Different temperatures such as $20^{\circ}C\;and\;30^{\circ}C$ did not affect root colonization by strain E681. This colonization was associated with a consistent increase in foliar growth of cucumber in the greenhouse. These results indicate that strain E681 is a promising PGPR strain for application to agricultural systems, particularly during the winter season.

• 한국식품조리과학회지
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• 제6권2호
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• pp.51-58
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• 1990

Quality deterioration of barley drink during storage was examined by measuring viable count, titratable acidity (TA), turbidity and pH of barley drinks with or without barley particles stored at temperatures of 20, 25, 30, and 35$^{\circ}C$. Qualitative analysis of organic acids in spoiled barley drink was also performed. TA of barley drink during storage increased to 0.009, 0.0095, 0.0097 and 0.020% at 20, 25, 30 and 35$^{\circ}C$, respectively. TA reached the mixima between 7 and 10 days of storage and reduced from then on. pH values followed the exactly reverse trend of TA. The rate of bacterial spoilage of barley drinks was faster when it was stored at higher temperatures. The numbers of bacteria were in the range between 9.0${\times}10^6-8.0{\times}10^8$ cells/ml depending on the storage temperatures and the different brands. Those samples with higher bacterial growths showed higher optical densities. Volatile organic acids such as acetic, formic, propionic, isobutyric, isovaleric acids were detected in addition to ethyl alcohol. Non-volatile organic acids such as pyruvic, lactic, oxalacetic, succinic, fumaric acids were detected. Among them, acetic acids were most important in their quantities. Five different kinds of spoilage bacteria were isolated and identified as Bacillus Licheniformis, Bacillus coagulans, Badillus cirulans, Bacillus stearothermophilus and Bacillus brevis, all of which were found to form endospores.

• Journal of Microbiology
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• 제40권3호
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• pp.199-204
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• 2002

A microsporidium, from cabbage white bntteflies, Pieris rapae, collected in Korea, was purified and characterized according to its gene structure, spore morphology and pathogenicity. From the observation of the isolate by SEM and TEM, the endospores, exospores and nuclei, about 12 polar filament coils of the polar tube and posterior vacuoles were all identified. The nucleotide sequence was determined for a portion of genomic DNA which spans the V4 variable region of the small subunit rRNA gene. Comparison with the GenBank database for 15 other microsporidia species suggests that this isolate is most closely related to Nosema species. The pathogenicity against cabbage white butterflies was quantified by inoculating variable doses of spores to the second instar larvae. Peroral inoculation at a dosage of 10$\^$8/ spores/ml resulted in the death of all larvae prior to adult eclosion, but at lower spore dosages of 10$\^$4/-10$\^$5/ spores/ml, many adults successfully emerged. The median lethal dose (LD$\_$50/) was deter-mined to be 4.6$\times$10$\^$6/ spores/ml and the isolate also transmitted transovarially to the progeny eggs at a frequency of 92%.

• 한국동물위생학회지
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• 제39권2호
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• pp.131-136
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• 2016

Clostridium novyi (C. novyi) is a gram positive, non-capsulated, motile, obligatory anaerobe that produces endospores. Both C. novyi type A and B produce a bacteriophage encoded lethal alpha toxin which belongs to a family of large clostridial cytotoxins. These large clostridial cytotoxins of C. novyi bind to the uncharacterized receptors on host vascular endothelial cells, which leads to the loss of integrity of the vascular endothelium with subsequent edema, refractory hypotension, organ failure, and sudden death. A total of 13 sudden death cases were submitted to Chonbuk National University-Veterinary Diagnostic Center between June and October, 2015. The samples, mainly liver, were collected in sterile vials after necropsy and processed within 12~24 hours for diagnosis, isolation and identification of C. novyi. All of the 4 gram positive samples showed amplification by PCR. Out of 4 positive samples, 3 were detected to be C. novyi type B and 1 was detected as C. novyi type A. Based on the 16S rDNA sequence analysis, 1 case (150564) showed 99% similarity with C. novyi type A while other 3 cases (150388, 150557 and 150775) presented 99% similarity with C. novyi type B. Based on the results, C. novyi was found to be prevalent in Korean pig farms and causes sudden death to finishing pigs or sows during summer season. Thus, C. novyi should be considered for differential diagnosis on sudden death cases during the summer season.

• Food Science and Biotechnology
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• 제16권6호
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• pp.1072-1077
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• 2007

Bacterial endospores, especially those of Bacillus and Clostridium genera, are the target of sterilization in various foods. We used Bacillus subtilis ATCC 6633 spores to screen novel antimicrobial substances against spores from medicinal plants. We collected 79 types of plant samples, comprising 42 types of herbs and spices and 37 types of medicinal plants used in traditional medicine in Korea and China. At a concentration of 1%(w/v), only 14 of the ethanol extracts exhibited antimicrobial activity against B. subtilis spores of at least 90%. Crude extracts of Torilis japonica, Gardenia jasminoides, Plantago asiatica, Fritllaria, and Arctium lappa showed particularly high sporicidal activities, reducing the spore count by about 99%. Consideration of several factors, including antimicrobial activity, extraction yields, and costs of raw materials, resulted in the selection of T. japonica, G. jasminoides, A. lappa, and Coriandrum sativum for the final screening of novel antimicrobial substances. Verification tests repeated 10 times over a 4-month period showed that the ethanol extract of T. japonica fruit reduced aerobic plate counts of B. subtilis spores the most, from $10^7$ to $10^4\;CFU/mL$ (99.9%) and with a standard deviation of 0.21%, indicating that this fruit is the most suitable for developing a novel antimicrobial substance for inactivating B. subtilis spores.

• Journal of Species Research
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• 제9권1호
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• pp.26-34
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• 2020

The phylum Bacteroidetes covers phenotypically diverse groups of Gram negative rods that do not form endospores, and currently includes 6 classes, 6 orders, 33 families and 380 genera. Members of Bacteroidetes can be aerobic and anaerobic heterotrophs, hydrogen utilizing chemolithotrophs, or methylotrophs. They can be isolated from diverse habitats including terrestrial and aquatic environments, environments with extreme physicochemical conditions, and animal and plant hosts. During a series of extensive surveys of prokaryotic species diversity in Korea, bacterial strains belonging to Bacteroidetes were isolated from various sources of aquatic and terrestrial environments. A total of 22 isolates were obtained, which represent 22 unrecorded species in Korea belonging to 14 genera of 6 families. Sixteen species among them were assigned to Flavobacteriaceae, two species were to Sphingobacteriaceae, and single species was to each of the families Bacteroidaceae, Balneolaceae, Chitinophagaceae and Cytophagaceae. At genus level, Chryseobacterium (5 species) and Flavobacterium (5 species) were the most abundant genera, and single species were obtained for the genera Bacteroides, Baloneola, Terrimonas, Dyadobacter, Aquimarina, Arenibacter, Gillisia, Gilvibacter, Salinimicrobium, Winogradskyella, Pedobacter and Sphingobacterium. The detailed descriptions of each unrecorded species are provided.

• 한국구조물진단유지관리공학회 논문집
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• 제27권1호
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• pp.103-108
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• 2023

이 연구에서는 자발적 균열 치유 콘크리트에 적용할 수 있는 미생물자원을 확보하기 위한 기초 연구를 수행하였다. 이를 위해 본 실험에서는 생체광물 형성 미생물을 시료에서 분리하고 시멘트 내부 생존 및 탄산칼슘 석출량을 비교하여 적합한 미생물자원을 확보하였다. 시료에서 내생포자(endospore)를 형성하는 Bacillus 계열의 박테리아를 분리하여 16S rRNA 염기서열 분석법으로 동정한 6종의 미생물이 생성하는 탄산칼슘 석출량을 비교하였다. 탄산칼슘 석출량이 가장 많은 Bacillus velezensis와 Bacillus subtilis의 2종의 미생물을 선별하였고, 모르타르에 첨가 후 양생하여 위상차 현미경 관찰을 통해 미생물의 생존을 확인하였다. 또한 모르타르에 인위적 균열을 발생시켜 미생물에 의해 생성된 균열치유물질에 의한 자발적 균열 치유 작용을 확인할 수 있었다.

• 한국해양생명과학회지
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• 제8권1호
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• pp.50-55
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• 2023

프로바이오틱스는 다양한 환경에서 분리되어 왔으며, Bacillus 균주는 유산균과 같은 일반적인 프로바이오틱스의 한계를 보완할 수 있는 내생포자 형성 능력으로 인해 프로바이오틱스 균주 중에서 유리하다. 본 연구의 목적은 한국에서 오염되지 않은 환경으로 알려진 울릉도 토양에서 분리된 Bacillus 균주의 프로바이오틱스 잠재성을 조사하는 것이다. 토양 시료는 울릉도 각지에서 채취하였으며, 항생제 내성과 효소 활성을 평가하였다. 항생제에 내성을 나타내지 않는 6개의 Bacillus 균주를 확보하였고 이후에 효소 활성을 검사하였다. 인체에 악영향을 미칠 수 있는 β-glucuronidase 효소는 활성이 나타나지 않았으며, 시중에서 판매되고 있는 Bacillus 프로바이오틱스와 유사한 효소의 활성과, 추가적으로 펩타이드 가수분해효소인 Leucine arylamidase의 활성이 나타난 NB-1 균주가 확인되었다. 이에, 추가적인 효능 연구 및 안정성 실험을 통해 프로바이오틱스 균주로서의 가능성을 모색해야 할 필요가 있다고 판단된다.