• 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 Microbiology and Biotechnology
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• v.16 no.4
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• pp.569-575
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• 2006

The 530 stem-loop is a 46 nucleotide stem-loop structure found in all small-subunit ribosomal RNAs. Phylogenetic and mutational studies by others suggest the requirement for Watson-Crick interactions between the nucleotides 505-507 and 524-526 (530 pseudoknot), which are highly conserved. To examine the nature and functional significance of these interactions, a random mutagenesis experiment was conducted in which the nucleotides in the proposed pseudoknot were simultaneously mutated and functional mutants were selected and analyzed. Genetic analysis revealed that the particular nucleotide present at each position except 524 was not exclusively critical to the selection of functional mutants. It also indicated that basepairing interactions between the positions 505-507 and 524-526 were required for ribosomal function, and much weaker base-pairing interactions than those of the wild-type also allowed high ribosomal function. Our results support the hypothesis that the 530 pseudoknot structure may undergo a 'conformational switch' between folded and unfolded states during certain stages of the protein synthesis process by interacting with other ligands present in its environment.

• Microbiology and Biotechnology Letters
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• v.45 no.3
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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.

• 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.

• Biomedical Science Letters
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• v.23 no.2
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• pp.96-103
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• 2017

Nocardia species (spp.) are opportunistic pathogen in immunocompromised hosts. The genus Nocardia contains more than 70 species. Nocardia takedensis has been recently reported as a new species of the genus Nocardia. In this study, we describes the first clinical isolate of N. takedensis from the skin lesion in Busan, Korea. For the identification of clinical isolate to the species level as N. takedensis, classical methods (colony morphology, biochemical characteristics, and antimicrobial susceptibility), molecular method (16S rRNA gene sequencing), and MS (mass spectrometry) analysis were conducted. Clinical isolates grew slowly on the culture media (5% sheep blood agar and chocolate agar) under 5% $CO_2$ condition. Especially, carotene pigmentation was detected well on the media. Using mass spectrometry, Nocardia isolate was not identified to the species level. However, molecular method based on 16S rRNA sequencing confirmed the isolate as N. takedensis correctly. N. takedensis isolate was partial positive for acid-fast bacilli on the Ziehl-Neelsen method. And it was observed to be resistance to amoxicillin/clavulanic acid and ciprofloxacin. Our results provide useful information to develop optimal identification protocol of N. takedensis in clinical diagnostic laboratories.

• Journal of Microbiology and Biotechnology
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• v.25 no.5
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• pp.709-717
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• 2015

Airborne bacteria from hog farms may have detrimental impacts on human health, particularly in terms of antibiotic resistance and pathogen zoonosis. Despite human health risks, very little is known about the composition and diversity of airborne bacteria from hog farms and hog-related spray fields. We used pyrosequencing analysis of 16S rRNA genes to compare airborne bacterial communities in a North Carolina hog farm and lagoon spray field. In addition, we isolated and identified antibiotic-resistant bacteria from both air samples. Based on 16S rRNA gene pyrosequence analysis, Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria were the dominant phyla in airborne bacterial communities from both hog farm and spray field sites. Within the Firmicutes genera, Clostridium spp. were more abundant in the hog farm, whereas Staphylococcus spp. were higher in the spray field. The presence of opportunitic pathogens, including several Staphylococcus species and Propionibacterium acnes, was detected in both bioaerosol communities based on phylogenetic analysis. The isolation and identification of antibiotic-resistant bacteria from air samples also showed similar results with dominance of Actinobacteria and Proteobacteria in both hog farm and spray field air. Thus, the existence of opportunistic pathogens and antibiotic resistant bacteria in airborne communities evidences potential health risks to farmers and other residents from swine bioaerosol exposure.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.6
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• pp.900-905
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• 2009

We analyzed succession of the bacterial communities during composting of animal manure in three individual facilities. Polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis (DGGE) targeting for the bacterial 16S rRNA gene were used to clarify the changes of bacterial community throughout each composting process. Our study revealed that the bacterial community structures differed during the composting process. The bacterial community in composting of facility A showed little change throughout the process. In the compost sample from facility B, its community had a small shift as the temperature increased. In compost from facility C, the temperature dynamically changed; it was shown that various bacterial communities appeared and disappeared as follows: in the initial phase, the members of phylum Bacteroidetes dominated; in the thermophilic phase, some bacteria belonging to phylum Firmicutes increased; towards the end, the community structure consisted of three phyla, Bacteroidetes, Firmicutes, and Proteobacteria. This study provides some information about the bacterial community actually present in field-scale composting with animal manure.

• Journal of Animal Reproduction and Biotechnology
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• v.34 no.3
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• pp.157-165
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• 2019

This study was conducted to analyze the diversity census of fecal microbiome in horses using meta-analysis of equine 16S rRNA gene sequences that are available in the Ribosomal Database Project (RDP; Release 11, Update 5). The search terms used were "horse feces (or faeces)" and "equine feces (or faeces)". A total of 842 sequences of equine feces origin were retrieved from the RDP database, where 744 sequences were assigned to 10 phyla placed within Domain Bacteria. Firmicutes (n = 391) and Bacteroidetes (n = 203) were the first and the second dominant phyla, respectively, followed by Verrucomicrobia (n = 58), Proteobacteria (n = 30) and Fibrobacteres (n = 24). Clostridia (n = 319) was the first dominant class placed within Bacteroidetes while Bacteroidia (n = 174) was the second dominant class placed within Bacteroidetes. The remaining 98 sequences were assigned to phylum Euryarchaeota placed within Domain Archaea, where 74 sequences were assigned to class Methanomicrobia. The current results will improve understanding of the diversity of fecal microbiome in horses and may be used to further analyze equine fecal microbiome in future studies.

• Journal of Food Hygiene and Safety
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• v.30 no.4
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• pp.372-375
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• 2015

A lactic acid bacterium LP2 strain, which was previously isolated from a natural cheese, was confirmed to produce 1,4-dihydroxy-2-naphthoic acid (DHNA), a bifidogenic growth factor. The strain was identified as Lactobacillus plantarum (99% identity) by a homology search of the 16S rRNA gene sequence and named Lactobacillus plantarum LP2. The culture supernatant of the strain presented an antimicrobial activity against Helicobacter pylori KCTC 12083, where the DHNA might have influenced on the activity.

• Journal of Microbiology and Biotechnology
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• v.25 no.9
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• pp.1537-1541
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• 2015

Previous detection methods for Citrobacter are considered time consuming and laborious. In this study, we have developed a rapid and accurate detection method for Citrobacter species in pork products, using matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry (MS). A total of 35 Citrobacter strains were isolated from 30 pork products and identified by both MALDI-TOF MS and 16S rRNA gene sequencing approaches. All isolates were identified to the species level by the MALDI-TOF MS, while 16S rRNA gene sequencing results could not discriminate them clearly. These results confirmed that MALDITOF MS is a more accurate and rapid detection method for the identification of Citrobacter species.