• 한국식품영양과학회지
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• 제33권7호
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• pp.1092-1097
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• 2004

큰느타리버섯의 기능성 식품으로서 활용도를 높이기 위해 동결 건조된 자실체에서 분리한 조다당체 추출물이 면역세포 활성에 미치는 효과를 조사한 결과는 다음과 같다. 조다당체 추출물은 300 및 1,000 $\mu$g/mL 농도에서 비장세포의 증식을 유도하였으며, 이 때 비장세포는 IL-6와 IFN-${\gamma}$ 분비를 유도하는 것으로 나타났다 조다당체 추출물은 농도 의존적으로B세포의 증식을 유도하였으며, 특히 100 $\mu$g/mL농도 이상에서는B세포의 증식이 현저히 증가하는 것으로 나타났다. 그리고 조다당체 추출물 1,000 $\mu$g/mL 농도에서 B세포가 생산하는 IgGl, IgG2a, IgG3의 분비량이 현저히 증가하였다. 또한 농도 의존적으로 대식세포주의 일산화질소 생산을 유도하였으며, 대식세포가 분비하는 IL-6, TNF-$\alpha$, GM-CSF의 생산도 현저히 증가하는 것을 확인할 수 있었다.

• 대한화장품학회지
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• 제30권4호
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• pp.457-462
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• 2004

N-Acetyl-D-glucosamine (NAG)는 보습제로 사용되어지는 히아루론산의 구성물질인 뮤코 다당류의 일종이며, 특히 화장품으로서 응용은 보습제로서의 사용이 최초이다. 본 실험에서는 게나 새우의 껍데기에서 추출된 키틴을 탈아세틸화 하여 얻은 NAG를 화장품 원료로서 적용하고자 하였다. 현재 기능성 주름 원료로 알려진 레티놀(retinol)과 NAG를 비교하기 위하여 섬유아세포의 활성능력 및 콜라겐 생성촉진 효과를 비교 실험하였으며, 제형 내에서의 안정성을 위하여 HPLC로 역가를 측정하였다. 실험결과, 게의 껍질로부터 유도된 NAG는 피부에 자극을 전혀 주지 않으면서 섬유아세포의 세포활성 및 콜라겐의 생성을 촉진시키는 효과를 나타내었으며, 헤어리스 마우스를 대상으로 실험을 실시한 결과 피부층의 변화를 통하여 주름의 감소 효능을 볼 수 있었다.

• Korean Chemical Engineering Research
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• 제47권4호
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• pp.446-452
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• 2009

최근 청정대체에너지로 각광을 받고 있는 dimethyl ether(DME)를 천연가스를 이용하여 직접 생산하는 1단계법의 고정층 촉매 반응기를 모사하였다. 1단계법의 고정층 반응기의 경우, 발열 반응인 메탄올 합성반응과 메탄올 탈수 반응이 동시에 일어나기 때문에 촉매의 비활성화를 일으킬 수 있는 hot spot의 발생을 막는 것이 가장 중요하다. 따라서 향후 상용공정에 적용 가능한 향류 냉각방식(count-current cooling system)과 포화액체 풀비등 방식(pool boiling system)을 적용하여 반응기 거동을 모사하고 이를 비교하였다. CO 전환율과 DME 생산성 면에서 향류 냉각방식이 더 효과적이었다. 하지만 포화비등액체 풀비등 방식이 더 작은 온도 범위에서 운전되어 hot spot(국소 고온점)의 가능성을 낮추고 더 안정적인 반응기 운전범위를 확보할 수 있었다.

• Preventive Nutrition and Food Science
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• 제19권3호
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• pp.194-203
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• 2014

Yam (Dioscorea batatas) is widely consumed as functional food for health promotion mainly in East Asia countries. We assessed whether yam root (tuber) or bark (peel) extracts stimulated the activity of osteoblasts for osteogenesis. MC3T3-E1 cells (mouse osteoblasts) were treated with yam root extracts (water or methanol) (study I) or bark extracts (water or hexane) (study II) within $0{\sim}10{\mu}g/mL$ during the periods of osteoblast proliferation (5~10 day), matrix maturation (11~15 day) and mineralization (16~20 day) as appropriate. In study I, both yam root water and methanol extracts increased cell proliferation as concentration-dependent manner. Cellular collagen synthesis and alkaline phosphatase (ALP) activity, both the indicators of bone matrix protein and inorganic phosphate production for calcification respectively, were also increased by yam root water and methanol extract. Osteoblast calcification as cell matrix Ca and P accumulation was also increased by the addition of yam root extracts. In study II, yam bark extracts (water and hexane) increased osteoblast proliferation and differentiation, as collagen synthesis and ALP activity and osteoblast matrix Ca and P deposition. The study results suggested that both yam root and bark extracts stimulate osteogenic function in osteoblasts by stimulating bone matrix maturation by increasing collagen synthesis, ALP activity, and matrix mineralization.

• 한국응용과학기술학회지
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• 제26권3호
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• pp.279-287
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• 2009

Fisher-Tropsch synthesis for the production of hydrocarbon from syngas was investigated on 20% cobalt-based catalysts (20% Co/HSA, 20% Co/Si-MMS), which were prepared by home-made supports with high surface areas such as high surface alumina (HSA) and silica mesopores molecular sieve (Si-MMS). In the gas phase reaction by syngas only, 20% Co/Si-MMS catalyst was shown in higher CO conversion and lower carbon dioxide formation than 20% Co/HSA, whereas the olefin selectivity was higher in 20% Co/HSA than in 20% Co/Si-MMS. In the effect of n-hexane added in syngas, the selectivities of $C_{5+}$ and olefin were increased by comparing the supercritical phase reaction with the gas phase reaction in addition to reduce unexpected methane and carbon dioxide.

• Journal of Microbiology and Biotechnology
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• 제23권12호
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• pp.1785-1790
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• 2013

The synthetic machinery of ATF4 (activating transcription factor 4) is activated in response to various stress conditions involved in nutrient restriction, endoplasmic reticulum homeostasis, and oxidation. Stress-induced inhibition of proteasome activity triggers the unfolded protein response and endoplasmic reticulum stress, where ATF4 is crucial for consequent biological events. In the current study, we showed that the $NAD^+$-dependent deacetylase, SIRT1, suppresses ATF4 synthesis during proteasome inhibition. SIRT1 depletion via transfection of specific siRNA into HeLa cells resulted in a significant increase in ATF4 protein, which was observed specifically in the presence of the proteasome inhibitor MG132. Consistent with SIRT1 depletion data, transient transfection of cells with SIRT1-overexpressing plasmid induced a decrease in the ATF4 protein level in the presence of MG132. Interestingly, however, ATF4 mRNA was not affected by SIRT1, even in the presence of MG132, indicating that SIRT1-induced suppression of ATF4 synthesis occurs under post-transcriptional control. Accordingly, we propose that SIRT1 serves as a negative regulator of ATF4 protein synthesis at the post-transcriptional level, which is observed during stress conditions, such as proteasome inhibition.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.198-198
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• 2011

Organocatalysis is a relatively new and popular area within the field of chiral molecule synthesis. It is one of the main branches of enantioselective synthesis with enzymatic and organometallic catalysis. In recent years, immense high quality studies on catalysis by chiral secondary amines were reported. These progresses instantly led to different organocatalytic activation concepts, so thousands of researchers from academia and the chemical industry are currently involved in this field and new ideas, new approaches, and creative thinking have been rapidly emerged. Organocatalysts, some of which are natural products, appear to solve the problems of metal catalysts. Compared to metal-based catalysis, they have many advantages including savings in cost, time, and energy, easier experimental procedure, and reduction of chemical waste. These benefits originate from the following factors. First, organocatalysts are generally stable in oxygen and water in the atmosphere, there is no need for special equipments or experimental techniques to operate under anhydrous or anaerobic conditions. Second, organic reagents are naturally available from biological materials as single enantiomers that they are easy and cheap to prepare which makes them suitable for small-scale to industrial-scale reactions. Third, in terms of safety related catalysis, small organic molecules are non-toxic and environmentally friendly. Therefore, the purpose of this research is to develop novel synthetic methods and design for various organocatalyst. Furthermore, it is expected that these organocatalysts can be applied to a variety of asymmetric reactions and study the transition state of these reactions using a metal sulface. Here, we report the synthesis of unprecedented organocatalysts, proline and pyrrolidine derivatives with quaternary carbon center.

• Mycobiology
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• 제38권2호
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• pp.102-107
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• 2010

We identified a gene for $\beta$-1,3-glucan synthesis (GBG1), a nonessential gene whose disruption alters cell wall synthesis enzyme activities and cell wall composition. This gene was cloned by functional complementation of defects in $\beta$-1,3-glucan synthase activity of the the previously isolated Saccharomyces cerevisiae mutant LP0353, which displays a number of cell wall defects at restrictive temperature. Disruption of the GBG1 gene did not affect cell viability or growth rate, but did cause alterations in cell wall synthesis enzyme activities: reduction of $\beta$-1,3-glucan synthase and chitin synthase III activities as well as increased chitin synthase I and II activities. GBG1 disruption also showed altered cell wall composition as well as susceptibility toward cell wall inhibitors such as Zymolyase, Calcofluor white, and Nikkomycin Z. These results indicate that GBG1 plays a role in cell wall biogenesis in S. cerevisiae.

• Journal of Microbiology and Biotechnology
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• 제22권10호
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• pp.1446-1451
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• 2012

Levodopa or L-3,4-dihydroxyphenylalanine (L-DOPA) is the precursor of the neurotransmitter dopamine. L-DOPA is a famous treatment for Parkinson's disease symptoms. In this study, electroenzymatic synthesis of L-DOPA was performed in a three-electrode cell, comprising a Ag/AgCl reference electrode, a platinum wire auxiliary electrode, and a glassy carbon working electrode. L-DOPA had an oxidation peak at 376 mV and a reduction peak at -550 mV. The optimum conditions of pH, temperature, and amount of free tyrosinase enzyme were pH 7, $30^{\circ}C$, and 250 IU, respectively. The kinetic constant of the free tyrosinase enzyme was found for both cresolase and catacholase activity to be 0.25 and 0.4 mM, respectively. A cyclic voltammogram was used to investigate the electron transfer rate constant. The mean heterogeneous electron transfer rate ($k_e$) was $5.8{\times}10^{-4}$ cm/s. The results suggest that the electroenzymatic method could be an alternative way to produce L-DOPA without the use of a reducing agent such as ascorbic acid.

• Plant Biotechnology Reports
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• 제3권3호
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• pp.225-241
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• 2009

We investigated the transcriptional profiles of Japanese indigenous grape cultivar 'Koshu' (Vitis vinifera) leaf and berry skin during ripening. In leaf, 64 genes were abundantly transcribed at the end of $v{\acute{e}}raison$ (14 weeks post-flowering), whereas the expression of 61 genes was upregulated at the end of ripening (20 weeks post-flowering). In berry skin, 67 genes were abundantly transcribed at the end of $v{\acute{e}}raison$, whereas the expression of 86 genes was upregulated at the end of ripening. Gene expression associated with biological processes was activated in both tissues at the end of ripening. The expression of genes associated with photosynthesis, sugar synthesis, anthocyanin synthesis, cinnamic acid synthesis, and amino acid metabolism was observed in leaf and berry skin during ripening, together with the accumulation of sugars, anthocyanins, cinnamic acids, and amino acids. Transcripts of AUX/IAA family proteins that repress the activities of auxin-induced proteins were expressed in berry skin at the end of $v{\acute{e}}raison$. Transcripts of genes related to the ubiquitin-proteasome system that degrades AUX/IAA family proteins were abundantly expressed in berry skin at the end of ripening, suggesting that the expansion of skin cells at $v{\acute{e}}raison$ is suppressed by AUX/IAA family proteins, and that the ubiquitin-proteasome system induces the expansion of skin cells during ripening by degrading AUX/IAA family proteins. These transcriptional profiles, which provide new information on the characteristics of 'Koshu' grapevine during ripening, may explain the unique characteristics of 'Koshu' grape in comparison with those of European grapes used for winemaking, and may contribute to the improvement of 'Koshu' grape quality.