• Korean Journal of Microbiology
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• v.42 no.4
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• pp.286-293
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• 2006

Three hundred thirty two bacterial colonies which were able to degrade crude oil were isolated from soil samples that were contaminated with oil in Daejon area. Among them, one bacterial strain was selected for this study based on its low surface tension ability, and this selected bacterial strain was identified as Pseudomonas sp. G314 through physiological-biochemical tests and analysis of its 16S rRNA sequence. Pseudomonas sp. G314 showed a high resistance to antibiotics such as ampicillin, chloramphenicol, spectinomycin, and streptomycin, and heavy metals such as Li, Cr, and Mn. It was found that the optimal pH and temperature for biosurfactant production of Pseudomonas sp. G314 were pH 7.0 and $30^{\circ}C$, respectively. After seven hours of inoculated, the biosurfactant activity reached the maximum, and surface tension of the culture broth was decreased from 72 to 25 dyne/cm. The crude biosurfactant was obtained from the culture broth by acid precipitation, followed by solvent extraction, evaporation and then freeze drying. The CMC (critical micelle concentration) value of the crude biosurfactant was 20 mg/L.

• Korean Journal of Environmental Agriculture
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• v.31 no.1
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• pp.52-59
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• 2012

BACKGROUND: Cultivation of genetically modified(GM) crops rapidly has increased in the global agricultural area. Among those, herbicide resistant GM crops are reported to have occupied 89.3 million hectares in 2010. However, cultivation of GM crops in the field evoked the concern of the possibility of gene transfer from transgenic plant into soil microorganisms. In our present study, we have assessed the effects of herbicide-resistant GM Chinese cabbage on the surrounding soil microbial community. METHODS AND RESULTS: The effects of a herbicide-resistant genetically modified (GM) Chinese cabbage on the soil microbial community in its field of growth were assessed using a conventional culture technique and also culture-independent molecular methods. Three replicate field plots were planted with a single GM and four non-GM Chinese cabbages (these included a non-GM counterpart). The soils around these plants were compared using colony counting, denaturing gradient gel electrophoresis and a species diversity index assessment during the growing periods. The bacterial, fungal and actinomycetes population densities of the GM Chinese cabbage soils were found to be within the range of those of the non-GM Chinese cabbage soils. The DGGE banding patterns of the GM and non-GM soils were also similar, suggesting that the bacterial community structures were stable within a given month and were unaffected by the presence of a GM plant. The similarities of the bacterial species diversity indices were consistent with this finding. CONCLUSION: These results indicate that soil microbial communities are unaffected by the cultivation of herbicide-resistant GM Chinese cabbage within the experimental time frame.

• Journal of Microbiology and Biotechnology
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• v.23 no.4
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• pp.437-443
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• 2013

The diversity of culturable non-actinobacterial (NA) bacteria associated with four species of South China Sea gorgonians was investigated using culture-dependent methods followed by analysis of the bacterial 16S rDNA sequence. A total of 76 bacterial isolates were recovered and identified, which belonged to 21 species of 7 genera, and Bacillus was the most diverse genus. Fifty-one percent of the 76 isolates displayed antibacterial activities, and most of them belonged to the Bacillus genus. From the culture broth of gorgonian-associated Bacillus methylotrophicus SCSGAB0092 isolated from gorgonian Melitodes squamata, 11 antimicrobial lipopeptides including seven surfactins and four iturins were obtained. These results imply that Bacillus strains associated with gorgonians play roles in coral defense mechanisms through producing antimicrobial substances. This study, for the first time, compares the diversity of culturable NA bacterial communities among four species of South China Sea gorgonians and investigates the secondary metabolites of gorgonian-associated B. methylotrophicus SCSGAB0092.

• Korean Journal of Agricultural Science
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• v.10 no.1
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• pp.146-155
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• 1983

Fundamental study was carried out to elucidate the mechanisms of biological degradation of dyestuff in environments. A few bacterial strains which were capable of degrading amarnath were obtained from soil through an extensive screening program and identified by microbiolological properties. Conditions for bacterial growth and amaranth degradation were characterized and optimized, and the degradation products were identified. The results were as follows. 1. The most active strain A12-1 to be capable of degradation of amaranth was identified as Pseudomonas sp. 2. Optimal conditions for growth of the strain A12-1 were:$35^{\circ}C$ and pH 7.5, and growth was markedly increaesd by aeration. 3. Degradation of amaranth by the strain was accessed under similiar conditions for growth, however significantly inhibited when the culture was aerated. 4. Both bacterial growth and amaranth degradation were gradually decreased with increased concentration of amaranth in the culture. 5. Reaction of the crude enzyme from the strain A12-1 was optimal at $35^{\circ}C$ and pH 7.5 for degrading amaranth. 6. Sodium naphthionate and R-amino salt were found to be the products of amaranth degradation by the strain A12-1.

• Journal of Life Science
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• v.21 no.1
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• pp.134-140
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• 2011

One hundred forty five bacterial colonies which were able to degrade crude oil were isolated from soil samples that were contaminated with oil in the Daejon area. Among these colonies, one bacterial strain was selected for this study based on its low surface tension ability, and this selected bacterial strain was identified as Pseudomonas sp. Z1 through physiological-biochemical tests and analysis of its 16S rRNA sequence. Pseudomonas sp. Z1 showed a high resistance to antibiotics such as chloramphenicol and ampicillin, as well as heavy metals such as lithium, manganese, and barium. It was found that the optimal pH and temperature for biosurfactant production of Pseudomonas sp Z1 were pH 6.0-7.0 and $30^{\circ}C$, respectively. After ten hours of inoculation, the biosurfactant activity of the culture broth decreased rapidly, and had maximum surface tension (28 dyne/cm) after twenty-one hours incubation. The biosurfactant activity of the culture broth was also decreased up to 2% NaCl concentration.

• Journal of Embryo Transfer
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• v.30 no.3
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• pp.257-260
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• 2015

Reproductive disorders in cows cause economic loss in livestock farms. Reproductive diseases, such as follicular cyst, luteal cyst, endometritis, pyometra, and repeat breeding cause infertility. Among these diseases, endometritis and pyometra are uterine infections that are leading causes of infertility. This study was performed to investigate the causative agents of uterine diseases using bacterial culture. Bacteria were obtained from the reproductive organs (vagina, uterine cervix, and uterine horn) of dairy cow diagnosed with endometritis or pyometra, and cultured on blood agar. The colonies obtained from cultivation for 24 hours were passaged. To identify the bacteria, the colonies grown in passaged culture Gram stained and applied to an automatic biochemical microbial identification system. Escherichia coli were commonly detected in vagina, uterine cervix, and uterine horn of dairy cows diagnosed to pyometra. The cows having endometritis showed not only Escherichia coli but also Pantoea spp. and Klebsiella spp. strains. Dairy cows that were infected with Escherichia coli in uterus caused mastitis or digestive disease. These results suggest that sanitary feeding and management beforehand are needed to prevent bacterial infections.

• Journal of Microbiology and Biotechnology
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• v.23 no.1
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• pp.40-46
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• 2013

A variety of nuruk were collected from various provinces in Korea, and their microflora profiles were analyzed at the species level. A total of 42 nuruk samples were collected and when the viable cell numbers in these nuruk were enumerated, the average cell numbers of bacteria, fungi, yeast, and lactic acid bacteria from all nuruk were 7.21, 7.91, 3.49, and 4.88 log CFU/10 g, respectively. There were no significant differences in viable cell numbers of bacteria or fungi according to regions collected. Bacillus amyloliquefaciens and B. subtilis were the predominant bacterial strains in most samples. A significant portion, 13 out of 42 nuruk, contained foodborne pathogens such as B. cereus or Cronobacter sakazakii. There were various species of lactic acid bacteria such as Enterococcus faecium and Pediococcus pentosaceus in nuruk. It was unexpectedly found that only 13 among the 42 nuruk samples contained Aspergillus oryzae, the representative saccharifying fungi in makgeolli, whereas a fungi Lichtheimia corymbifera was widely distributed in nuruk. It was also found that Pichia jadinii was the predominant yeast strain in most nuruk, but the representative alcohol fermentation strain, Saccharomyces cerevisiae, was isolated from only 18 out of the 42 nuruk. These results suggested that a variety of species of fungi and yeast were distributed in nuruk and involved in the fermentation of makgeolli. In this study, a total of 64 bacterial species, 39 fugal species, and 15 yeast species were identified from nuruk. Among these strains, 37 bacterial species, 20 fungal species, and 8 yeast species were distributed less than 0.1%.

• Korean Journal of Organic Agriculture
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• v.19 no.spc
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• pp.190-193
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• 2011

Organic and chemical fertilizer amendments are an important agricultural practice for increasing crop yields. In order to maintain the soil sustainability, it is important to monitor the effects of fertilizer applications on the shift of soil microorganism, which control the cycling of many nutrients in the soils. Here, culture-dependent and culture-independent approaches were used to analyze the soil microorganism and community structure under six fertilization treatments, including green manure, rice straw compost, rapeseed cake, pig mature compost, NPK +pig mature compost, NPK and control. Both organic and chemical fertilizers caused a shift of the cultural microorganism CFUs after treatments. Bacterial CFUs of the organic fertilization treatments were significantly higher than that of chemical fertilization treatments. The DGGE profiles of the bacterial communities of the samples showed that the green manure treatment was a distinct difference in bacterial community, with a greater complexity of the band pattern than other treatments. Cluster analyses based on the DGGE profile showed that rice straw compost and pig mature compost had a similar banding pattern and clustered together firstly. Rapeseed cake, NPK, NPK +pig manure compost and control clustered together in other sub-cluster and clearly distinguished from green manure.

• Journal of Veterinary Clinics
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• v.38 no.1
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• pp.45-48
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• 2021

A 6-year-old, 26 kg spayed female Great Dane presented with back pain and hindlimb paresis. On neurological examination, severe pain was detected on the lumbosacral joint displaying nerve-root signature. The animal presented with lower motor neuron paresis with normal deep pain perception. Radiographic examination revealed narrowing of the lumbosacral joint disc space with endplate destructive lysis. Magnetic resonance imaging of the lumbosacral joint revealed a cauda equina compression, especially on the left. On T2 and T1-weighted images, a mass sized 1 × 1 cm was identified laterally to the left of the lumbosacral joint with hyperintense signal. The lumbosacral joint was stabilized by applying the dorsal distraction fixation-fusion technique and dorsal laminectomy. The soft tissue mass was removed, and a bacterial culture was performed. Coagulase-negative Staphylococcus spp. were detected and discospondylitis was treated with clindamycin for 6 weeks. The patient showed clinical improvement without pain and hindlimb paresis until 6 months follow-up postoperatively.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.49 no.4
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• pp.198-207
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• 2023

Objectives: This study investigated causative strains and their antibiotic sensitivity in patients who were hospitalized for maxillofacial odontogenic infections at a tertiary center in South Korea over the past 10 years with the aim of providing guidelines for the selection of appropriate empirical antibiotics. Materials and Methods: Patients with head and neck fascial space abscesses due to odontogenic infections who underwent incision and drainage surgery with pus culture tests between 2013 and 2022 at the Department of Oral and Maxillofacial Surgery, Dankook University Hospital were included. The bacterial isolates and antibiotic sensitivity of each strain were analyzed for 2013-2022, 2013-2017, and 2018-2022. The affected fascial spaces were classified into primary, secondary, and deep neck spaces. Results: In the 192 patients included in this study, 302 strains were detected. Viridans streptococcus had the highest frequency (51.7%), followed by Prevotella spp. (16.9%), Staphylococcus spp. (5.6%), and Klebsiella pneumoniae (4.6%). The identification rate of viridans streptococcus significantly increased from 41.8% in 2013-2017 to 60.9% in 2018-2022. Viridans streptococcus showed an antibiotic sensitivity of 80.5% to ampicillin; the sensitivity to penicillin antibiotics decreased over the study period. Antibiotic susceptibility was approximately 94% for third-generation cephalosporins. K. pneumoniae, which was identified at a high percentage in patients with deep neck space infection, showed increasing antibiotic resistance to most antibiotics over the study period. Conclusion: Viridans streptococcus was identified in head and neck fascial space abscesses with the highest frequency. Empirical antibiotics should be effective against this strain; penicillin antibiotics are considered inappropriate. For effective treatment of deep neck space abscesses, bacterial culture and antibiotic sensitivity tests performed as soon as possible are essential.