• Journal of Microbiology
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• v.39 no.2
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• pp.142-145
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• 2001

Changes in the Activities of several antioxidant enzymes in transformed human dermal microvascular endothelial Cells (HMEC-1) by infection with the obligate intracellular bacterium Orientia tsutsugamushi, the causative agent of scrub typhus, were investigated. The activities of glucose-6-phosphate dehydrogenase, catalase, and glutathione peroxidase were significantly decreased in HMEC-1 cells infected with Ο. tsutsugamushi. However, the level of superoxide dismutase increased slightly. Furthermore, Increased levels of intracellular peroxide was observed in HMEC-1 during infection. These results support the hypothesis that cells infected by this intracellular bacterium experience oxidant-mediated injury that may eventually contribute to cell death.

• Journal of Microbiology
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• v.42 no.2
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• pp.69-73
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• 2004

Vibrio vulnificus, a Gram-negative bacterium found in estuarine waters, is responsible for over 95％ of all seafood-related deaths in the United States. As a result of a temperature downshift to 5$^{\circ}C$, this organism enters the viable but nonculturable (VBNC) state. Changes in the membrane fatty acid (FA) composition of V. vulnificus may be a contributing factor to the ability of this organism to enter into and survive in the VBNC state. This hypothesis was tested by incubating the organism at 5$^{\circ}C$ in arti-ficial sea water and analyzing the cells' FAs during the initial hours of temperature and nutrient down-shift. Prior to downshift, the predominant FAs were 16:0, 16:1 and 18:0. During the first four hours of downshift, statistically significant changes occurred in 15:0, 16:1, 16:0, 17:0, and 18:0. These results indicate that changes in FA composition occur prior to entry of V. vulnificus into the VBNC state, suggesting that the ability to maintain membrane fluidity may be a factor in this physiological response. Cells in which fatty acid synthesis was inhibited did not survive, indicating that active fatty acid metab-olism is essential for entry of cells into the VBNC state.

• Proceedings of the Korean Environmental Health Society Conference
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• 2005.11a
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• pp.101-103
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• 2005

This study was performed to investigate the changes of Bacillus sp. of traditional Korean soy sauce (kan-jang) and soybean paste (doen-jang) during the ripening and storage for 12 months. All of the preparation methods for soy sauce and soybean paste followed the recommendations of the Korea Food Research Institute. The soy sauce and soybean paste were analyzed at 0, 6, and 12 months. The numbers of Bacillus sp. of meju (soybean cakes) or soy sauce and soybean paste at the initial stage were significantly higher than those of soybeans (p<0.05). The number of Bacillus sp. increased in soy sauce and soybean paste after 12 months of ripening and storage. This study indicates that this comes from the preparation and fermentation of meju. It is suspected that the organoleptic characteristics of soy sauce and soybean paste might be inferior over 1 year of storage time. Therefore, more research fur overall microbiological quality changes of soy sauce and soybean paste during the storage period should be conducted to interpretate this characteristics more accurately.

• Journal of Applied Biological Chemistry
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• v.49 no.4
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• pp.176-179
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• 2006

Electron beam irradiation was applied to examine the microbial growth and qualities of vacuum-packaged Astragalus membranaceus, a Korean medicinal herb. Samples were irradiated at dose of 2, 4, 8, 12, and 16 kGy, respectively. Microbiological data on A. membranaceus showed that populations of total bacteria, yeast and mold, total coliforms were significantly reduced with increase of irradiation dose. Populations of microorganisms in A. membranaceus were decreased by 2-3 log cycles at 8 kGy irradiation. Color measurements showed that electron beam treatment caused negligible changes in Hunter color L, a, and b values of A. membranaceus. Sensory evaluations showed that there were no significant changes among the samples. These results suggest that electron beam irradiated A. membranaceus have better microbial safety and qualities, compared with the non-irradiated control.

• Food Science and Preservation
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• v.5 no.1
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• pp.41-47
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• 1998

Physicochemical properties and microbiological quality chanties were investigated on mixed fruit and vegetable juices (apple, carrot and cucumber) stored at 4$^{\circ}C$ without pasteurization(NT), with light piasteurization (LP; 66$^{\circ}C$, 10 sec) and with full pasteurization(FP; 90$^{\circ}C$, 60 sec). Effects of ultrafiltration (UF) on the changes during storage were also examined. pH, viscosity, a-value and b-value remained relatively constant and all samples revealed Newtonian characterisitics. Total acidity and turbidity tended to increase slightly; however, total vitamin C content and L-value slowly decreased during storage up to about 2 months. During the first 4 weeks storage, soluble solids content slowly increased and then decreased. Mold and Yeast and Bacteria were not detected in LP, UP and UF treated samples during storage studied; however, E. coli were detected after 24 days storage. No distinctive storage effects were found among samples prepared; however, ultrafiltration had a considerable effect on the color and soluble solids content of mixed fruit and vegetable juice.

• Journal of Microbiology
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• v.34 no.4
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• pp.300-304
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• 1996

To define the effects of zooplankton and phytoplankton to bacteria, bacterial numbers, frequency of dividing cells (FDC) and size distribution were performed with image analysis in the surface layer of Lake Soyang. In August 1992, when Anabaena was blooming, the bacterial number increased at daytime. Bacterial numbers and FDC value had a negative correlation (r = 0.83, P < 0.01). Bacterial size spectrums were dynamically changed during the day and night, especially the small bacteria less than $0.5\;{\mu}m^3$. Meanwhile, in October, after the bloom, the bacterial number was only one third of that in August, even though the FDC was higher than that in August. The bacterial numbers of small size class dropped at 13:00. But the size spectrums were relatively constant during the night time. These results suggest that the bacterial growth was tightly coupled with phytoplankton during Anabaena bloom. And after the bloom, the bacterial number was controlled grazing activity of zooplankton at daytime.

• Korean Journal of Microbiology
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• v.12 no.3
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• pp.101-114
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• 1974

The fine structure of HeLa cells treated with several mycotoxin-producing fungi (Aspergillus flavus ATCC 15517, Aspergillus parastiticus RIB 1037, Penicillium toxicarium RIB 4002, Penicillium cirinum SWU)238, Penicillium islandicum IFO 5235, Penicillium tadum IFO 5787 and Pencillium brunneum RIB 1172) has been examined and some details have been descried. The normal HeLa cell have numerous microvilli, large ovoid nucleus, pleomorphic mitochondria, electron-dense body, Golgi complex, mid-body and endoplasmic reticulum etc. Certain specific structural changes induced by culture filtrates of several mycotoxin-producing fungi have been noted. These alterations induced disappearance of Golgi complex, rER vacuolization, nucleolus attachment to the nuclear envelope nad appearance of certain vacuoles. There were not any changes by the treatment of culture filtrates of non-toxic fungi and only cell debris of some specimens can be observed by the injury of culture filtrates. The experimental animals treated with mycotoxin-producing fungi (Aspergillus flavus ATCC 15517, Aspergillus parasilicus RIB 1037, Penicillum citrinum SWU 238, Penicillium toxicarium RIB 4002, and Penicillium islandicum IFO 5235) were mal cells treated with culture filtrates.

• Korean Journal of Microbiology
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• v.19 no.1
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• pp.8-13
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• 1981

The content of sulfhydryl compounds in Chlorella cells during the life cycle in the synchronous culture is determined spectrophotomatically at 250nm(pH7.0) using p-CMB as SH-reagent. The changes in the content of-SHl compounds and protein in Chlorella cells is measured during the life cycle in connection with cell division and analyzed. 1) The amounts of total ninhydrin reactive substance increased with growth of cells but increased the more at the $L_4$ stage(cytokinesis stage) than at the $L_2$ stage (nuclear division stage). 2) The sulfhydryl content of Chlorella cells increased strikingly at the $L_2$ stage and decreased markedly at the $L_4$ stage. 3) The amounts of values -SH/protein showed a peak at the $L_2$ stage. The increase of the amount of total-SH compounds of cells during the nuclear division period was considered to be caused by the weighty roles of protein-SH groups for the formation of nuclear division apparatus and for the enzyme activity.

• Korean Journal of Microbiology
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• v.22 no.2
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• pp.91-96
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• 1984

The changes in the activities of Cellulase and Xylanase of A. phoencis during the life cycle were surveyed by using synchronized culture technique. Avicelase activity of the fungus was reached at peak in the initial hyphal growth stage, but decreased gradually during the conidiophore formation, vesicle-phialide formation, and sporulation stages in decreasing order. CMCase, Salicinase, and Xylanase activities were raised very high in the initial hyphal growth stage, but decreased gradually in conidiophore formation and vesicle-phialide formation stages, and then increased, more or less, in the sporulation stage.

• Korean journal of food and cookery science
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• v.5 no.1
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• pp.31-41
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• 1989

The effects of salting degree of cabbage on the chemical, microbiological, textural changes and taste of Korean whole cabbage Kimchi fermented at $21^{\circ}C$ was studied. Low salted Kimchi (1.8% NaCl, soaking for 2 hr. in 20% brine) was showed higher total acdity than high salted Kimchi II(3.1% NaCl, Soaking For 8 hr in 20% brine) and III(2.9% NaCl, no soaking in 20% brine). The changes in growth of lactic acid bacteria was relevant to the salt content of whole cabbage Kimchi. Kimchi I was showed higher growth rate of Lactic acid bacteria and slower death rate constant of Lactic acid bacteria than that of Kimchi II and III. In palatability test, salty taste of Kimchi II, III was more salty than that of Kimchi I ($p{\leqq}0.01$) and total evaluation of Kimchi I, II was more palatable than Kimchi III ($p{\leqq}0.05$) at 3rd's day (optimum taste). Cutting force by Rheometer was well correlated with the salt content of Kimchi.