• Korean Journal of Microbiology
• /
• v.51 no.3
• /
• pp.312-317
• /
• 2015

Pyrosequencing of 16S rDNA tags was used to obtain the bacterial diversity and community structure in the uncultured seawaters as well as in the cultured seawaters, which were collected from the 7 ports (Cheonbu, Hyunpo, Taeha, Namyang, Sadong, Dodong, and Jeodong) and 1 seashore (Guam) around the Ulleng island, Korea. Alphaproteobacteria were the most abundant group in the clean seawaters such as seawaters of Taeha and Sadong ports. Gammaproteobacteria proportion increased depending upon the wastewater amounts mixed with the seawaters such as seawaters of Namyang, Dodong, and Jeodong ports. The genuses of Alteromonas (from samples of Cheonbu, Taeha, Guam, Namyang, Sadong), Shewanella (from sample of Jeodong), and Vibrio (from samples of Hyunpo and Dodong) were dominant group in each of the cultured seawaters incubated in marine broth (Difoco). The results suggest that the incoming wastewaters to the port seawaters contribute to the dynamic change of the marine bacterial community around the Ulleng island.

• Korean Journal of Microbiology
• /
• v.50 no.2
• /
• pp.169-172
• /
• 2014

Recently, Hepatitis C virus (HCV) replication system has been established using human hepatoma cells (huh cell) and a variety of HCV clones. In this study, we established an infectious HCV replication system using huh7.5 cells and J6/JFH1 clone (genotype 2a). In addition, we investigated the antigen presentation capability of HCV-infected huh7.5 cells to HCV-specific T cells. Interestingly, HCV-infected huh7.5 cells were not capable of activating HCV-specific T cells. However, huh7.5 cells stimulated by exogenous HCV peptide were able to activate HCV-specific T cells, which was shown to produce TNF-${\alpha}$ and IFN-${\gamma}$. We further examined if HCV infection has an inhibitory effect on the expression of MHC class I molecule of huh7.5 cells. We found that HCV infection did not change the expression level of MHC class I molecule on huh7.5 cells.

• Journal of Applied Biological Chemistry
• /
• v.57 no.4
• /
• pp.287-294
• /
• 2014

To improve the shelf life of low-salt Kochujang, Korean hot pepper paste, antimicrobial materials were added at different times before and after aging. The kochujang was then packaged and stored at $30^{\circ}C$ for 15 weeks, and changes in microbiological and physiochemical properties were evaluated. Hunter a- and b-values decreased considerably during storage. The total color difference (${\delta}E$) was greater in the ethanol-chitosan (EC) treatment than in the control and after pasteurization (A-P) treatment. Gas was produced until the seventh week of storage. The control and the A-P treatments produced more gas than the other treatments, and these had the largest number of yeasts and aerobic bacteria. The pH of the EC treatment was higher than that of the other treatments, and the A-P treatment had the highest level of titratable acidity. During storage, the oxidation-reduction potential was lower in the EC and ethanol-mustard-chitosan (EMC) treatments. The reducing sugar content decreased remarkably in the control and A-P treatments, with high production of ethanol. There was a significant change in the content of amino-type nitrogen in the control and A-P treatments, and the content of ammonia-type nitrogen was lowest in the EMC treatment. In the sensory test of kochujang, the ethanol-mustard (EM) and ethanol (E) treatments were significantly higher than the EC, control, and A-P treatments (p <0.05). EM or E alone was effective in extending the shelf life of kochujang when added before aging.

• Korean Journal of Food Science and Technology
• /
• v.17 no.1
• /
• pp.45-50
• /
• 1985

Soy yogurt beverage(SYB) was prepared from soy protein concentrate and the effect of stabilizers on the sedimentation of SYB curd and the microbiological quality of SYB during storage were investigated. The curd in SYB precipitated significantly during the first one hour of storage and the sedimentation of curd was reduced by the addition of CMC of over 0.6%, PGA of over 0.2% or Na-alginate of over 0.05%. SYB could be kept for 66 days at $5^{\circ}C$ without significant change in viable cell count of lactic acid bacteria. pH, titratable, acidity and viable cell count of SYB were significantly changed from 42 days of storage at $25^{\circ}C$. Some of SYB samples were contaminated by fungi and the growth of fungi was greatly inhibited by the addition of K-sorbate of 0.005%.

• Journal of Microbiology
• /
• v.40 no.4
• /
• pp.295-300
• /
• 2002

Previously, we reported induced expression of developmentally regulated CTP-binding protein 2 (DRG2) in fish cells at the late stage of rhabdovirus infection. To investigate the biological role of fish DRG2 (fDRG2), we transfected CHSE-214 cells with an expression vector containing complete fDRG2 fused to the N-terminal end of an enhanced green fluorescent protein (EGFP). Low level expression of fDRG2-EGFP did not induce morphological change or cell death. However, a high level expression of fDRG2-EGFP induced cell rounding and caused depletion of the cell population in FACS analysis. Several truncated fragments were fused to EGFP. FACS analysis was conducted to determine the presence of cells expressing high levels of the resulting chimera. While cells expressing a high level of N-terminus were detected, those expressing high levels of the C-terminal fragment 243-290 containing the G4 motif were absent in FACS analysis. Based on these observations, we propose that overexpression of fDRG2 may induce cell rounding, a representative cytopathic effect of virus-infected cells in the late stage of infection and the C-terminus of the fDRG2 is essential for this function.

• Korean Journal of Microbiology
• /
• v.46 no.1
• /
• pp.33-37
• /
• 2010

Rhizobacterial strain isolated from barren soil, Bacillus subtilis RFO41 exhibits a high level of phosphate solubilizing activity and produces some phytohormones. Its promoting effect on the growth of Xanthium italicum Moore, a wild plant growing at lakeside barren land and thus a good candidate plant for revegetation of barren lakeside was evaluated in the in situ test for 19 weeks at Lake Paro, Kangwon-do. Strain RFO41 could enhance the dry weight of X. italicum by 67.7%. It also increased the shoot length of X. italicum plant by 21.1% compared to that of uninoculated control. Both growth enhancements had statistical significance. However, the inoculation did not show any effect on the root growth, which might be due to the breakage of tiny root. Denaturing gradient gel electrophoresis analysis showed that the inoculated bacteria were maintained in the soils, and the indigenous bacterial community did not exhibit any significant change. This plant growth promoting capability may be utilized as an environment-friendly and low cost revegetation method, especially for the sensitive areas such as barren lakeside lands.

• Food Science and Preservation
• /
• v.16 no.2
• /
• pp.299-303
• /
• 2009

To explore the preservation parameters of a prototype anti-inflammatory drink containing a Helianthus annuus seed extract, we first examined sweetness, pH and color changes, and temperature effects during preservation. Over 25 days, pH rose slightly from 3.50 to 3.65. Small color changes in L, a, and b values occurred on prolonged storage. Temperature most affected storage properties, which differed considerably at $10^{\circ}C$ and $40^{\circ}C$. Microbiological safety tests showed that the prototype drink was safe; neither general bacterial contamination nor Escherichia coli growth occurred. We concluded that the prototype drink was biologically and microbiologically safe on preservation.

• Korean Journal of Microbiology
• /
• v.13 no.3
• /
• pp.116-122
• /
• 1975

Calcium and magnesium in polished rice, polished barley, what flour, and corn which were used for Yakju fermentation were determined by atomic absorption spectrophotometry and their quantitative changes in the filtrates of mashes were checked at 24 hours intervals dueing the whole brewing period. The results obtained were as follows. 1) Mineral contens of raw materials(mg% of each anhydrous materials). Ca : polished rice 8.21, polished barley 26.11, wheat flour 66.10, corn 86.63 2) Mineral contents of kojies made from raw materials (mg %of each anhydrous materials). Ca : rice koji 26.36, barley koji 97.61, what flour koji 87.69, corn koji 16.13, seeding koji 28.76 Mg: rice koji 29.29, barley koji 39.84, what flour koji 244.50, corn koji 102.64, seeding koji 143.79 3) Quantitative changes of minerals in the fitrates of mashes. Calcium contents in the filtrates of mashes were increased gradually after mashing in the first stage but unchanged till the mashes were ripened after mashing in the second stage. On the other hand, magnesium cotents were decreased gradually after increase in the the other hand, magnesium contens were decreased gradually after increase in the first stage but showed a tendency to increase gradually in the second stage. 4)Mineral contents of Yakjues produced, marketing Yakju, and natural water for brewing (g/ml). Ca : rice Yakju 72.38, barley Yakju 84.08, what flour Yakju 105.32, corn Yakju 71.26, marketing Yakju 71.50, natural water for brewing 51.25 Mg :rice Yakju 93.67, barley Yakju 62.39, wheat flour Yakju 273.34, corn Yakju 321,60, marketing Yakju 90.00, natrual water for brewing 20.00 5) Mineral contents of Yakju residues (mg% of each anhydrous matrials). Ca : rice Yakju residues 209.70, barley Yakju residues 62.83, what flour Yakju residues 133.92, corn Yakju residues 60.64 Mg : rice Yakju residues 15.62, barley Yakju residuet 13.22, wheat flour Yakju residues 59.10, corn Yakju residues 67.38

• Korean Journal of Microbiology
• /
• v.24 no.4
• /
• pp.335-340
• /
• 1986

Two kind of ${\beta}-glucosidase$, tightly-bound enzyme(TBE) and loosely-bound enzyme(LBE), were obtained from the conidia of Aspergillus nidulans. The existence of enzymes in conidia was conformed by the fact that these enzyme activities were proportional to the number of conidia. The levels of enzyme activities were independent of aging of the conidia. Enzymes were characterized partially. In spite of the physical and chemical treatments of conidia, there was no significant change in TBE activity. The optimum pH and temperature was 6.0 and $55^{\circ}C$, respectively. Thermostability of the TBE was remarkably higher than that of mycelial ${\beta}-glucosidase$. The electrophoretic pattern of LBE was identical to that of mycelial ${\beta}-glucosidase$. These results suggest that conidial ${\beta}-glucosidase$ are involved in adaptation process of the conidia to variable environments.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.41 no.11
• /
• pp.1559-1564
• /
• 2012

Raisins (Thailand), dried mangos (Philippines), and dried figs (Iran) were gamma-irradiated (0~5 kGy), and their quality and detection characteristics were investigated. Microbiological characteristics were at safe levels when samples were irradiated at higher than 3 kGy. In color change after irradiation, dried mangoes were the most sensitive. Photostimulated luminescence (PSL) measurement was not applicable to dried fruits, showing negative or intermediate values for the irradiated samples. Thermoluminescence (TL) measurement was good for dried figs, exhibiting a glow curve in range of $150{\sim}200^{\circ}C$, where the signal intensity was dependent on the irradiation dose. Electron spin resonance (ESR) measurement was suitable for raisins and dried mangos, resulting in dose-dependent radiation-induced sugar radical signals.