• Microbiology and Biotechnology Letters
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• v.50 no.3
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• pp.414-421
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• 2022

In this study, we isolated Weizmannia ginsengihumi LGHNH (KCTC 14462BP) from 30-year-old wild Panax ginseng C.A. Meyer and elucidated the characteristics of the isolated bacterium and its industrial potential as an anti-aging material. W. ginsengihumi LGHNH was investigated to produce indole-3-acetic acid (IAA), a plant growth-promoting hormone (1.38 ㎍/ml to 2.22 ㎍/ml). We also confirmed the existence of bioconversion activity via the comparison of the ginsenoside content before and after fermentation. As for the converted minor ginsenoside, Rg2(R), Rg4, Rg6, Rg3(S), Rg3(R), Rk1, Rg5, Rh1(R), Rk3 and Rh4 are known to have high bioavailability and various skin effects. We measured mitochondrial membrane potential and ATP biosynthesis to elucidate W. ginsengihumi LGHNH cultured product (WCP) as an anti-aging material. As a result, the mitochondrial membrane potential in HaCaT cells with UVB decreased to 39.3% compared to the unirradiated group, but was recovered to 57.3% and 58.1% by 0.001% (v/v) and 0.01% (v/v) WCP, respectively. In addition, we measured mitochondrial ATP biosynthesis. It decreased to 94.3% compared to the unirradiated group with UVB, but was recovered to 105.3% and 105.7% by 0.001% (v/v) and 0.01% (v/v) WCP.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.4 no.1
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• pp.33-39
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• 1999

In order to understand the importance of tidal action and $NH_4{^+}$ -nitrification in the removal of dissolved oxygen (DO) and $NH_4{^+}$, concentrations of DO, $NH_4{^+}$, $NO_2{^-}$ and $NO_3{^-}$ were measured with time for water samples collected at different tidal state in the eutrophic macrotidal Han River estuary. Field measurements indicated that most environmental parameters, except for the water temperature and DO concentration, were tightly controlled by the eutrophic freshwater runoff and large-scale tidal action. Dark incubation of the water sample at $25^{\circ}C$ showed that the removal rates of DO and $NH_4{^+}$ in high tide sample were 2.76 ${\mu}M\;O_2\;d^{-1}$ and 1.76 ${\mu}M\;N\;d^{-1}$ respectively, and increased to 5.66 ${\mu}M\;O_2\;d^{-1}$ and 3.36 ${\mu}M\;N\;d^{-1}$ respectively, in low tide sample. These changes indicated that microbial degradation and uptake of organic matter and inorganic nutrients were more active during low tide. $NH_4{^+}$-nitrification responsible for total DO removal in low tide (23.81%) and $NH_4{^+}$ turnover rates due to $NH_4{^+}$-nitrification in low tide (0.18 $d^{-1}$) were approximately 3.7 times and 3 times, respectively, higher than those in high tide. These results indicated that $NH_4{^+}$ -nitrifying bacteria introduced into the Han River estuary during low tide played a significant role in the removal of DO and $NH_4{^+}$. The decreasing removal rates in DO and $NH_4{^+}$ with the increasing tidal level seemed to be associated with the salinity impact on the halophobic freshwater $NH_4{^+}$-nitrifying bacteria. The results implied that anthropogenic $NH_4{^+}$ sources should be treated prior to the freshwater runoff into the estuary for the effective control of $NH_4{^+}$ in the Han River estuary. These results also suggest that parallel ecological studies on the chemoautotrophic nitrifying bacteria are essential for the elucidation of nitrogen cycles in the eutrophic Han River estuary.

• Korean Journal of Microbiology
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• v.47 no.4
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• pp.302-307
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• 2011

Native chitin deacetylase of Aspergillus nidulans was purified to apparent homogeneity by a combination of phenyl-Sepharose and Q-Sepharose column chromatography. In order to analyze the amino acid residues involved in the enzyme activity, the enzyme was chemically modified with chemical agent, which selectively reacted with the specific amino acid residue on the protein. When the enzyme was chemically modified with diethylpyrocarbonate, which specifically reacted with histidine residues on the protein, the activity was eliminated. The chitin deacetylase, chemically modified with 100 ${\mu}M$ modifier at the residue of arginine or tyrosine, has shown to have decreased activities. It was shown that the modification at aspartic acid or glutamic acid did not affect the enzyme activity to a greater extent, which would not implicate that acid amino residues were directly involved in catalytic reaction and would affect on the global structures of the proteins. This results demonstrated that histidine and tyrosine residues of enzyme would participate in an important function of the chitin deacetylase activity.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2006.11a
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• pp.255-260
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• 2006

천수만의 수리 역학 및 수질 모델을 위하여 3차원 수리역학 모델(EFDC)과 21개 수질 변수에 대한 수질 모델이 접합된 3차원 수리역학-부영양화 모델(HEM-3D)을 이용하였다. 관측 자료에 대한 모델 검증 결과, 조위는 관측치에 비해 5% 정도, 유속은 10% 정도 작은 값을 보였으며, 지각은 모델 결과치가 고정항에서 늦고 간월도에서 빠르게 나타났다. 수질 항목, 특히 용존산소의 관측치에 나타난 전반적인 분포 양상을 잘 재현하고 있었으며, 항목별 기여도 분석에서는 수질 모델이 퇴적물에 의한 산소 소비에 민감하게 반응하고 있으며, 용존산소 변화에 있어서 퇴적물에 의한 영향이 중요한 역할을 하고 있음을 보여주었다. 본 모델 결과는 기존의 모델들과 비교하여 천수만 해역의 해수 유동 특성을 잘 재현하고 있으며, 본 모델과 연계된 수질 모델의 오염물 확산과 수질 항목들의 거동을 이해할 수 있는 정보를 제공하였다. 그럼에도 불구하고 본 연구를 통하여 나타난 문제점은, 수질 예측 모델에 필요한 수질 변수들의 관측 자료와 양식장에 의한 오염 부하량 자료가 충분하지 못하며, 퇴적물에 의한 수질 변화를 정량화할 수 있는 모델의 개발이 시급하다는 것이다. 특히 퇴적물에 의한 산소 요구량은 유기퇴적물이 미생물 등에 의해 분해되는 과정에서 요구되는 산소량으로서, 해수 유동 조건의 변화와 오염부하에 의한 유기퇴적물의 집적이 주된 요인이다. 방조제 건설 이후 해수유동 조건의 변화와 더불어 지속적으로 오염물이 유입되고, 담수 및 천수만의 수질이 점점 악화되고 있다. 따라서 이러한 오염부하와 퇴적물에 대한 관리대책이 시급한 것으로 판단되며, 향후 정확한 수질 예측을 위해서는 본 연구에서 나타난 문제점들에 대한 재고가 필요할 것으로 사료된다.

• Korean Journal of Food Science and Technology
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• v.41 no.2
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• pp.162-166
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• 2009

In an effort to determine the effect of ingredients on the sensory characteristics of dongchimi, 10 different samples of dongchimi were prepared in various combinations of 4 ingredients most notably red pepper, garlic, ginger, and green onion and their physicochemical, microbiological, and sensory characteristics were assessed. Each ingredient utilized for the preparation of dongchimi did not affect changes in pH and titratable acidity, but exerted significant effects on sensory scores of overall acceptability, acid odor, salty, and hot taste. In cluster analysis using the 'Ward' method, dongchimi samples were classified into three groups. The first group was the samples prepared with a variety of ingredients including garlic, and the second group included samples prepared with the sole ingredient, except for red pepper. The third group had features similar to those of the sample prepared without other ingredients. It was determined that garlic played a crucial role in the sensory properties of dongchimi, and the addition of various ingredients enhanced hot taste and reduced acid odor, sourness, moldy odor, and carbonated taste by their interaction.

• Korean Journal of Ecology and Environment
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• v.37 no.4 s.109
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• pp.436-447
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• 2004

Wetland plants have evolved specialized adaptations to survive in the low-oxygen conditions associated with prolonged flooding. The development of internal gas space by means of aerenchyma is crucial for wetland plants to transport $O_2$ from the atmosphere into the roots and rhizome. The formation of tissue with high porosity depends on the species and environmental condition, which can control the depth of root penetration and the duration of root tolerance in the flooded sediments. The oxygen in the internal gas space of plants can be delivered from the atmosphere to the root and rhizome by both passive molecular diffusion and convective throughflow. The release of $O_2$ from the roots supplies oxygen demand for root respiration, microbial respiration, and chemical oxidation processes and stimulates aerobic decomposition of organic matter. Another essential mechanism of wetland plants is downward water movement across the root zone induced by water uptake. Natural and constructed wetlands sediments have low hydraulic conductivity due to the relatively fine particle sizes in the litter layer and, therefore, negligible water movement. Under such condition, the water uptake by wetland plants creates a water potential difference in the rhizosphere which acts as a driving force to draw water and dissolved solutes into the sediments. A large number of anatomical, morphological and physiological studies have been conducted to investigate the specialized adaptations of wetland plants that enable them to tolerate water saturated environment and to support their biochemical activities. Despite this, there is little knowledge regarding how the combined effects of wetland plants influence the biogeochemistry of wetland sediments. A further investigation of how the Presence of plants and their growth cycle affects the biogeochemistry of sediments will be of particular importance to understand the role of wetland in the ecological environment.

• Korean Journal of Microbiology
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• v.51 no.4
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• pp.435-439
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• 2015

THO/TREX complex plays an important role in transcriptional elongation, mRNA processing, nuclear RNA export, and genome stability. A fission yeast, Schizosaccharomyces pombe, SPBC577.04 gene encoding the ortholog of THOC5, a component of THO/TREX complex, was identified and characterized. The S. pombe thoc5 (spthoc5) is not essential for both growth and mRNA export, but deletion of the spthoc5 gene caused growth defect and slight accumulation of $poly(A)^+$ RNA in the nucleus. And the functional spThoc5-GFP protein is localized mainly in the nucleus. Co-immunoprecipitation analysis showed that the Hpr1(THOC1) protein, an evolutionally well-conserved component of THO/TREX complex, interacted with spThoc5 as well as Tho2(THOC2), another subunit of THO complex. These results suggest that S. pombe Thoc5 as a component of THO/TREX complex is also involved in mRNA export from the nucleus.

• Korean Journal of Microbiology
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• v.51 no.2
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• pp.181-185
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• 2015

Tho2/THOC2 is a subunit of the THO complex that plays important roles in mRNP biogenesis connecting transcription with mRNA maturation and export. A fission yeast, Schizosaccharomyces pombe, ortholog of Tho2/THOC2 was identified from the genome database. Tetrad analysis showed that the S. pombe tho2 is essential for growth. Repression or overexpression of the tho2 gene caused growth defect with elongated cells, abnormal DNA distribution, and accumulation of $poly(A)^+$ RNA in the nucleus. And the functional GFP-Tho2 protein is localized mainly in the nucleus. Yeast two-hybrid analysis showed that Tho2 interacted with Tex1, another subunit of THO complex. These results suggest that S. pombe Tho2 is also involved in mRNA export from the nucleus and is a component of THO complex.

• Korean Journal of Microbiology
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• v.35 no.4
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• pp.258-265
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• 1999

Entry into meiosis in the yeast Saccharomyces cerevisiae is regulated by two major factors: the cell type MATa/MAT${\alpha}$ and the nutriational state (starvation) of the cell. The two independent regulations act through IME1and IME2 expression to initiate meiosis. IME2 encodes a meiosis-specific protein kinase, and it enabled MATa/MAT${\alpha}$ diploid cells to undergo meiosis and sporulation. The PCR mutagenesis method was applied for the isolation of thermosensitive ime2 mutants. Among sixty two mutants isolated from the phenotype of defective spore formation under the restrictive temperature, three with the most easily observed temperature-sensitive phenotype (ts ${\cdot}$ime2-11, ts ${\cdot}$ime2-12 and ts ${\cdot}$ime2-13) were selected for further study. To understand the detailed functions of IME2, we examined the defects of these mutants in the early meiotic pathway including the premeiotic DNA replication and exhibited decreased level in meiotic recombination. These results suggest that the IME2 gene plays essential role in meiotic recombination pathway as well as premeiotic DNA replication. As the result of the IME2 overexpression in ${\Delta}$mre4. moreover, it was suggested that the IME2 and MRE4 genes act on the same pathway of initiation step in meiotic recombination.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.8 no.2
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• pp.210-224
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• 2003

Sulfate reduction is a microbiological process which occurs ubiquitously in anaerobic marine environment. Sulfate reducing bacteria play a significant role in anaerobic decomposition of organic matter and regeneration of inorganic nutrients which supports the primary production in the water column (i.e., benthic-pelagic coupling) and, in special case, could be responsible for the harmful algal bloom in the coastal marine environment. Summary of the sulfate reduction rates reported in various marine sedimentary environments revealed that supply of organic substrates and presence of various electron acceptors (i.e., $O_2$, NO$_{3}$$^{[-10]}$ , Fe(III) and Mn(IV), etc.) for other aerobic and anaerobic respiration directly affect the sulfate reduction rate and relative significance of sulfate reduction in organic matter mineralization. Significance of temperature, macrophytes and bioturbation is discussed as factors controlling supply of organic substrates and distribution of electron acceptors. Finally, we suggest studies on the anaerobic microbiological processes associated with biogeochemical element cycles in the coastal environments of Korea where massive operation of organic enriched fish cage farm, frequent occurrence of toxic algal bloom and hypoxia and conservation of tidal flat are of major environmental issues.