• Microbiology and Biotechnology Letters
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• v.45 no.1
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• pp.43-50
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• 2017

A xylan-degrading bacterium (strain WJ-1) was isolated from soil collected from Jeju Island, Republic of Korea. Strain WJ-1 was characterized as a gram-positive, aerobic, and spore-forming bacterium. The predominant fatty acid in this bacterium was anteiso-$C_{15:0}$ (42.99%). A similarity search based on 16S rRNA gene sequences suggested that the strain belonged to the genus Streptomyces. Further, strain WJ-1 shared the highest sequence similarity with the type strains Streptomyces spinoveruucosus NBRC 14228, S. minutiscleroticus NBRC 13000, and S. glaucescens NBRC 12774. Together, they formed a coherent cluster in a phylogenetic tree based on the neighbor-joining algorithm. The DNA G+C content of strain WJ-1 was 74.7 mol%. The level of DNA-DNA relatedness between strain WJ-1 and the closest related species S. glaucescens NBRC 12774 was 85.7%. DNA-DNA hybridization, 16S rRNA gene sequence similarity, and the phenotypic and chemotaxonomic characteristics suggest that strain WJ-1 constitutes a novel subspecies of S. glaucescens. Thus, the strain was designated as S. glaucescens subsp. WJ-1 (Korean Agricultural Culture Collection [KACC] accession number 92086). Additionally, strain WJ-1 secreted thermostable endo-type xylanases that converted xylan to xylooligosaccharides such as xylotriose and xylotetraose. The enzymes exhibited optimal activity at pH 7.0 and $55^{\circ}C$.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.31 no.4 s.54
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• pp.305-310
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• 2005

To obtain effective and safe depigmenting agents, we investigated the effects of Scirpi rhizoma, a medicine among Chinese herbs, on melanogenesis. Dried S. rhizoma was refluxed with 70% aqueous ethanol and the extract was evaporated to dryness. To determine the effects as a whitening agent, various in vitro tests were performed such as free radical scavenging activity, melanin formation assay, tyrosinase activity and expression of tyrosinase, TRP-1 and TRP-2(western blot and RT-PCR) in B16 melanoma cells. S. rhizoma showed scavenging activities of free radicals and reactive oxygen species (ROS) with the $IC_{50}\;of\;638{\mu}g/mL$ against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and $21.7{\mu}g/mL$ against superoxide radicals in the xanthine/xanthine oxidase system, respectively. S. rhizoma significantly inhibited melanin production in B16 melanoma cells. S. rhizoma treatment(48 h) suppressed the biosynthesis of melanin up to 27% at 100{\mu}g/mL$ and reduced tyrosinase activity up to 31% at $100{\mu}g/mL$ in B16 melanoma cells. S. rhizoma was also able to significantly inhibit tyrosinase and TRP-1 expression in protein and mRNA level. These results suggest that S. rhizoma inhibited melanin biosynthesis by regulating tyrosinase activity and expression in B16 melanoma cells. Therefore, S. rhizoma may be useful as a new antioxidant and whitening agent to inhibit melanogenesis.

• Korean Journal of Microbiology
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• v.45 no.2
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• pp.193-199
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• 2009

A bacterium producing the halotolerant extracellular protease was isolated from squid jeotgal, and was identified as Bacillus sp. SJ-10 based on morphological, physiological and biochemical characteristics, as well as phylogenetic analysis using 16S rRNA gene sequence. The strain grew at $20^{\circ}C\sim55^{\circ}C$, pH 5~8, and 0%~14% NaCl and optimal growth conditions were $35{\pm}5^{\circ}C$, pH 7, and 5% NaCl. The major cellular fatty acids were anteiso-$C_{15:0}$, anteiso-$C_{17:0}$, and $C_{16:0}$ DNA G+C content was 50.58 mol% and menaquinone consisted of MK-7 Phylogenic analysis based on the 16S rRNA gene sequence indicated that SJ-10T belongs to the genus Bacillus. About 40 kDa of the salt-tolerant protease was purified by 40% ammonium sulfate saturation and Mono Q column chromatography. The optimal activity of the protease was pH 8 and stable at pH 5~10. The optimum temperature and NaCl concentration were $35{\pm}5^{\circ}C$ and $5{\pm}1%$, respectively.

• Journal of fish pathology
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• v.18 no.2
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• pp.133-146
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• 2005

A bacteriological survey in maricultured fish farms was conducted in Korea from 2002 to 2004. A total number of 166 Vibrio isolates were collected from diseased fishes, including olive flounder (133 isolates), black rock fish (8 isolates), red sea bream (6 isolates), shrimp (5 isolates), black sea bream (4 isolates), abalone (3 isolates) and other fishes (7 isolates). All isolates were phenotypically characterized and then groups were obtained using the traditional biochemical test. Representative isolates of each group were genotypically characterized with sequencing the 16S rRNA genes or 16S-23S intergenic space genes. Above 14 species of Vibrio were identified as V. ichthyoenteri (45 strains), V. alginolyticus (34 strains), V. harveyi (32 strains), Ph. damselae subsp. damselae (Formerly V. damsela, 10 strains), V. campbellii (6 strains), V. costicola-like (6 strains), V. fisheri (5 stains), V. fluvialis (4 strains) and others Vibrio sp. (24 strains) by combining of biochemial and genetic characteristics.

• Journal of Practical Agriculture & Fisheries Research
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• v.25 no.3
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• pp.14-18
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• 2023

White leg shrimps cultured in an inland private aquaculture farm with low salinity waters showed abnormal swimming behavior and appetite reduction in July 2022. Then, gradual mortality was observed in the aquaculture farm. During the diagnosis, bacterial strain KNUAF-SHP3 was isolated from the hepatopancreas of the dead shrimps. Based on the sequence of 16S rRNA gene, KNUAF-SHP3 was proved to be Shewanella sp., clustering into a group with S. algae MARS 14 and S. chilikensis JC5T. According to the result of experimental infection test, all shrimps challenged with high concentrations, 2.1×108 CFU/ml and 2.1×109 CFU/ml showed apparent disease symptoms and the cumulative mortality rates reached 100% in 7 days post challenge. These results emphasized that Shewanella isolate in this study can be a potential pathogen of white leg shrimp cultured in low salinity water.

• Korean Journal of Microbiology
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• v.42 no.1
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• pp.26-33
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• 2006

To understand the efficient process of biological nitrogen removal (BNR) system, the structure of bacterial communities in nitrification reactors was analyzed using PCR and terminal restriction fragment length poly morphism (I-RFLP) methods. In this study, we used an advanced treatment system with plotting media, Nutrient Removal Laboratory system, or the rumination type sequencing batch reactor (SBR) system. The terminal restriction fragments of ammonia-oxidizing bacteria (AOB) and other $\beta-proteobacteria$ were observed in all of three BNR systems. The nucleotide sequence analysis of terminal restriction fragments showed that Nitrosomonas and Nitrosolobus were major populations of AOB in SBR system, whereas uncultured $\beta-proteobacteria$ and Cardococcus australiensis were the predominant groups in other two BNR systems. Also the SBR system may be more efficient to enrich AOB. These results indicate that the different structure of bacterial community may be developed depending on the wastewater treatment systems, although the same influent is used.

• Journal of Food Hygiene and Safety
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• v.28 no.2
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• pp.188-193
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• 2013

Anatoxin-a, saxitoxin and neosaxitoxin are produced by Aphanizomenon flos-aquae that is a sort of the cyanobacteria phylum. Therefore, it is not permitted for food materials in Korea. Traditionally, the classification of cyanobacteria has been based on morphological characters such as trichome width, cell size, division planes, shape, and the presence of character such as gas vacuole. But, some diagnostic features, such as gas vacuole or akinetes, can show variation with different environmental or growth conditions and even be lost during cultivation. Therefore, we developed detection method for functional foods containing Aph. flos-aquae by PCR. To design the primer, 16S rRNA region of Aph. flos-aquae, Spirulina laxissima, and Spirulina spp. registered in the GeneBank (www.ncbi.nlm.nih.gov) have been used and for comparative analysis, BioEdit ver. 7.0.9.0. was used. As a result, we was design AFA-F1/AFA-R1 (363 bp) primer for the differentiation Aph. flos-aquae from chlorella, spirulina, green tea, and spinach. Also, it could be distinguished chlorella and spirulina products those are made to contain 1% Aph. flos-aquae.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.7
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• pp.312-320
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• 2020

The objective of the study was to undertake a phylogenetic diversity census of ruminal archaea based on a meta-analysis of 16S rRNA gene sequences that were publicly available in the Ribosomal Database Project. A total of 8,416 sequences were retrieved from the Ribosomal Database Project (release 11, update 5) and included in the construction of a taxonomy tree. Species-level operational taxonomic units (OTUs) were analyzed at a 97% sequence similarity by using the QIIME program. Of the 8,416 sequences, 8,412 were classified into one of three phyla; however, the remaining four sequences could not be classified into a known phylum. The Euryarchaeota phylum was predominant and accounted for 99.8% of the archaeal sequences examined. Among the Euryarchaeota, 65.4% were assigned to Methanobrevibacter, followed by Methanosphaera (10.4%), Methanomassillicoccus (10.4%), Methanomicrobium (7.9%), Methanobacterium (1.9%), Methanimicrococcus (0.5%), Methanosarcina (0.1%), and Methanoculleus (0.1%). The 7,544 sequences that had been trimmed to the V2 and V3 regions clustered into 493 OTUs. Only 17 of those 493 OTUs were dominant groups and accounted for more than 1% of the 7,544 sequences. These results can help guide future research into the dominant ruminal methanogens that significantly contribute to methane emissions from ruminants, research that may lead to the development of anti-methanogenic compounds that inhibit these methanogens regardless of diet or animal species.

• Microbiology and Biotechnology Letters
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• v.46 no.2
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• pp.127-134
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• 2018

In this study, 79 bacterial isolates were collected from the surface of marine algae Umbraulva japonica. As a result of analysis of 16s rRNA gene sequence, the 79 isolated bacteria were divided into 4 major groups: [Proteobacteria (74.69%), Actinobacteria (2.53%), Fimicutes (2.53%), and Bacteroidetes (20.25%)] - 7 classes (Actinobacteria, Flavobacteria, Sphingobacteria, Baciili, Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria), 12 orders, 17 families and 31 genera. The newly isolated 3 strains could be novel species because of less than 97% similarity in 16s rRNA sequence. Therefore, it is considered that additional experiments should be conducted together with the standard strain. Analysis of 79 bacterial antibacterial activity against human and fish pathogens, such as Edwardsiella tarda, Vibrio harveyi, Streptococcus iniae, Steptococcus parauberis, Escherichia coli, Steptococcus mutans, Listeria monocytogenes and Vibrio vulnificus, was performed by using the supernatant liquid and pellet. As a result, pellet of UJT9, UJT20 and UJR17 showed antibacterial activity against V. vulnificus, UJR17 also showed antibacterial activity against S. parauberis. UJT7 and UJT20, UJR17 have been identified as Bacillus sp. and Pseudomonas sp. and it may be safely assented that it's beneficial to carry out additional experiments for various applications.

• Korean Journal of Microbiology
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• v.49 no.3
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• pp.286-291
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• 2013

Soybean pastes with 8% (w/w) salinity were prepared instead of soybean paste with 14% (w/w) salinity to meet the growing demands of Korean's low sodium diet. After aging, white films had appeared on the surface of all low-salted soybean pastes [8% (w/w) salinity] unlike high-salted soybean pastes [14% (w/w) salinity]. All of eight microbes isolated from the surface film were identified as Pichia kudriavzevii. Eleven Bacillus strains with good characteristics of fermentation were isolated from traditionally fermented soybean pastes in order to preserve their unique flavors and aromas after aging, and as a result of analyzing the biochemical characteristics and 16S rRNA sequences, those were identified as B. subtilis, B. licheniformis, and B. methylotrophicus. All of the Bacillus isolates had antagonistic activities against 8 isolates of the film-forming yeasts and harbored the genes for synthesis of antimicrobial surfactants including lichenysin and/or surfactin.