• 한국미생물·생명공학회지
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• 제45권3호
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• pp.243-249
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• 2017

An agar-degrading bacterium, designated as the GNUM08123 strain, was isolated from samples of red algae collected from the Yongil Bay near East Sea, Korea. The isolated GNUM08123 strain was gram-negative, aerobic, motile, and beige-pigmented, with $C_{16:0}$ (25.9%) and summed feature 3 (comprising $C_{16:1}{\omega}7c/iso-C_{15:0}2-OH$, 34.4%) as its major cellular fatty acids. A similarity search based on the 16S rRNA gene sequence revealed that it belonged to class Gammaproteobacteria and shared 97.7% similarity with the type strain Vibrio chagasii $R-3712^T$. The DNA G+C content of strain $GNUM08123^T$ was 46.9 mol%. The major isoprenoid quinone was ubiquinone-8. The results of DNA-DNA relatedness and 16S rRNA sequence similarity analyses, in addition to its phenotypic and chemotaxonomic characteristics, suggest that strain GNUM08123 is a novel species within genus Vibrio, designated as Vibrio sp. GNUM08123. Agarase production by strain GNUM08123 was induced by agar and sucrose, but was repressed probably owing to carbon catabolite repression by glucose and maltose.

• 생태와환경
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• 제37권2호통권107호
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• pp.241-247
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• 2004

부영양 호수로부터 살조 세균을 분리하고 동정한 결과 Anabaena cylindrica NIES-19를 유릴 탄소원으로 이용하는 double layer방법으로 15종의 살조세균을 분리하였으며 높은 살조 활성을 나타내는 4종의 살조세균 AK-05, AK-07, AK-13 그리고 AK-28을 선별하여 살조 능력을 비교하였다. 이들 중에 AK-05가 가장 높은 살조 활성을 나타내었으며 이를 16S rDNA염기서열을 분석한결과 Acidovorax temperans와 99.5%의 유사성을 나타내어 Acidovorax temperans AK-05로 명명하였다. A. temperans AK-05의 배양 여액을 A. cylindrica NIES-19에 뚜렷한 살조 활성을 나타내었으며, 이것의 살조 활성 능력을 분석한 결과 살조 활성에 관여하는 주요 물질은 non-protein이며 열에 안정적이었다. 이러한 살조 활성 능력은 알칼리 조건과 25${\sim}$$30^{\circ}C$에서 가장 높게 나타냈다. 따라서 이와 같은 특성은 일반적으로 알칼리 조건을 야기하는 Cyanobacteria에 의한 water blooms이 발생하는 호수에 적용하는데 매우 유리할 것으로 여겨진다.

• Animal Systematics, Evolution and Diversity
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• 제34권3호
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• pp.143-151
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• 2018

A marine ciliate Amphisiella milnei (Kahl, 1932) $Horv{\acute{a}}th$, 1950 was discovered from the tidal pool of Baekdo Island, South Korea. The existence of extra cirri between leftmost frontal cirrus and buccal cirrus discriminates this species from its congeners. Its morphological features are described as follows: body size in vivo $110-130{\times}35-45{\mu}m$; elongate rectangular to elliptical in shape; two large and several small ring-shaped structures; yellowish cortical granules arranged irregularly on ventral side but longitudinally along dorsal kineties on dorsal side; 34-40 adoral membranelles, 3 frontal cirri, 1 buccal cirrus, 1 parabuccal cirrus, usually 2 extra cirri behind leftmost frontal cirrus, and 3 frontoventral cirri; amphisiellid median cirral row composed of 25-31 cirri with 27-36 left and 27-44 right marginal cirri; usually 5 transverse cirri and 2 pretransverse cirri with 7 dorsal kineties; two macronuclear nodules. In addition to, 18S rDNA sequence of A. milnei was analyzed to understand its phylogenetic relationship.

• Journal of Microbiology and Biotechnology
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• 제16권5호
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• pp.731-739
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• 2006

A bacterial strain HJ-14 was isolated as a producer of antioxidants from the coast of Jinhae in Korea. The isolate showed 43.4mol% of G+C content, and contained dihydrogenated ubiquinone with Q8 as a major quinone. Chemotaxonomic analysis as well as phylogenetic analysis, based on the 16S rDNA sequence, identified the isolate as a member of Alteromonas macleodii. For antioxidant production, the optimum medium composition was determined to be 3% dextrin, 0.5% ammonium sulfate, and 2-6% sodium chloride. Optimum culture conditions for production of antioxidant materials with strain HJ-14 were at pH 6.0-8.0 and $25-37^{\circ}C$. The chloroform extract of strain HJ-14 broth showed 1.96-17.5-fold higher antioxidant activity than other organic solvents in term of electron donating ability.

• Mycobiology
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• 제40권3호
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• pp.189-194
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• 2012

Four Cladobotryum isolates were collected from four different commercially grown mushroom types infected with cobweb disease in Cheongdo-gun and Chilgok-gun of Gyeongbuk Province, Korea in 2010. The isolates were identified as C. mycophilum from Agaricus bisporus and Pleurotus eryngii, C. varium from Flammulina velutipes and Hypsizygus marmoreus. The cultural characteristics of the four isolates were investigated using potato dextrose agar (PDA) media under nine different temperatures ranging from $5{\sim}32^{\circ}C$. Rapid growth of the isolates to colony diameters of 47~82 mm was observed at conditions of $18{\sim}22^{\circ}C$. No growth was observed at $32^{\circ}C$. C. mycophilum produced a yellowish red pigment while C. varium produced a cream colored pigment after cultivation for 25 days on PDA. Phylogenetic analysis of the internal transcribed spacer region and partial 28S rDNA from the four isolates confirmed they were C. mycophilum and C. varium. Cross pathogenicity tests revealed that the two isolates of C. mycophilum were highly pathogenic toward three mushroom types, but not toward H. marmoreus. The two isolates of C. varium were less pathogenic than those of C. mycophilum, but were pathogenic toward all mushroom types evaluated.

• Molecules and Cells
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• 제25권4호
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• pp.523-530
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• 2008

In this study, the species composition and population genetic properties of the sea slater, Ligia, in South Korea were investigated using mitochondrial and nuclear gene sequences. Two groups of sea slaters, genetically isolated from each other, a Western Group (WG) and an Eastern Group (EG) were identified. These groups exhibited considerable genetic divergence from Ligia exotica, previously recorded as a species inhabiting this country. These results indicate that there may be two species of Ligia in South Korea, but there is a small probability that both groups are L. exotica. A comparison of their genetic properties indicates that WG has a higher effective population size than EG, and that EG may have experienced a recent expansion, implying that it has a shorter history in South Korea than WG. These findings suggest that the South Korean sea slater populations may have been established as a result of several colonization events that can be traced on a continental scale by phylogeographic studies of sea slaters.

• Journal of Microbiology and Biotechnology
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• 제14권5호
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• pp.924-931
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• 2004

A bacteriocin-producing lactic acid bacterium, which strongly inhibited the Lactobacillus plantarum recognized as an important acid spoilage microorganism in kimchi fermentation, was isolated from kimchi. From morphological, physiological, sugar fermentation, biochemical tests, and l6S rDNA sequencing results, the isolate was identified as an Enterococcus sp. and designated as Enterococcus sp. K25. The bacteriocin produced by Enterococcus sp. K25 inhibited several Gram-positive bacteria, including Lb. plantarum, whereas it did not inhibit Gram-negative bacteria and yeasts. Optimal temperature and pH for the bacteriocin production were $25^\circ{C}$ and 5.5, respectively. Enterococcus sp. K25 was applied to kimchi manufacturing alone and together with other preservatives (i.e., chitosan and fumaric acid). In addition, growth of lactic acid bacteria, pH, and titratable acidity (TA) were measured during aging at $5^\circ{C}$ and $10^\circ{C}$. Inoculation of Enterococcus sp. K25 together with fumaric acid showed the most synergistic effect on extension of kimchi shelf-life. Compared to control (no addition), the treatment prolonged the kimchi shelf-life up to 6 days, whereupon the eight-point TA value recognized as the edible limit was reached.

• The Plant Pathology Journal
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• 제25권3호
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• pp.247-255
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• 2009

Root-knot nematode species, such as Meloidogyne hapla, M. incognita, M. arenaria, and M. javanica are the most economically notorious nematode pests, causing serious damage to a variety of crops throughout the world. In this study, DNA sequence analyses were performed on the D3 expansion segment of the 28S gene in the ribosomal DNA in an effort to characterize genetic variations in the three Meloidogyne species obtained from Korea and four species from the United States. Further, PCR-RFLP (Polymerase Chain Reaction-Restriction Fragment Length Polymorphism), SCAR (Sequence Characterized Amplified Region) PCR and RAPD (Randomly Amplified Polymorphic DNA) were also utilized to develop methods for the accurate and rapid species identification of the root-knot nematode species. In the sequence analysis of the D3 expansion segment, only a few nucleotide sequence variations were detected among M. incognita, M. arenaria, and M, javanica, but not M. hapla. As a result of our haplotype analysis, haplotype 5 was shown to be common in M. arenaria, M. incognita, M. javanica, but not in the facultatively parthenogenetic species, M. hapla. PCR-RFLP analysis involving the amplification of the mitochondrial COII and large ribosomal RNA (lrRNA) regions yielded one distinct amplicon for M. hapla at 500 bp, thereby enabling us to distinguish M. hapla from M. incognita, M. arenaria, and M. javanica reproduced via obligate mitotic parthenogenesis. SCAR markers were used to successfully identify the four tested root-knot nematode species. Furthermore, newly attempted RAPD primers for some available root-knot nematodes also provided some species-specific amplification patterns that could also be used to distinguish among root-knot nematode species for quarantine purposes.

• 미생물학회지
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• 제25권4호
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• pp.282-289
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• 1987

Pseudomonas putida KU816에서 분리한 플라스미드 pKU10의 여러가지 특성을 조사하고 그 제한 효소 지도를 작성하였다. pKU 10은 암펴설런, 테트라사이클린, 클로람페니콜에 대한 내성 유전자를 갖는 작은 R factor로서 마이토마이신 C에 의하여 큐어링 된다. 플라스미드의 크기는 9.4Kb로 측정되었다. pKU 10은 Pseudomonas와 E.coli블 숙주로 하였을 때 안정하게 형질 발현이 되다. 또한 pKU 10의 불화합성균은 IncP-I으로 조사되었다. Eco RI, Xho I. SaiI, BglII, SmaI은 pKU 10 DNA를 한 부위에서 자르고, Pst I은 두 부위, Hind Ill는 여섯 부위에서 자른다. 제한 효소 지도는 제한 효소를 이중, 삼중으로 완전 소화시키거나, 부분 소화시켜서 얻었다. pKU 10은 Pseudomonas속에서 유용한 클로닝 벡터호 이용된 것으로 기대된다.

• 한국환경농학회지
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• 제36권4호
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• pp.299-305
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• 2017

탄저병이 발생한 자두에서 11개 탄저병균을 순수 분리하여 병원성을 검정한 후 PDA에 접종하여 $25^{\circ}C$에서 7-10일 동안 배양하면서 각 균주의 균사 생장속도, colony의 특징과 색, 포자 형태 및 크기를 관찰하였다. 각 균주의 genomic DNA를 추출하여 rDNA-ITS 영역을 증폭한 다음, PCR을 하여 염기서열을 해독하였다. 각 균주의 배양적 특성, 포자의 형태와 크기 및 염기서열을 NCBI GenBank의 염기서열과 상동성을 비교하여 동정한 결과 6개 균주는 Colletotrichum acutatum으로, 5개 균주는 C. gloeosporioides로 동정되었다.