• Journal of Nutrition and Health
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• 제32권6호
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• pp.726-731
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• 1999

Many studies show that the bone loss in postmenopausal women is closely related with status of vitamin K. The purpose of this study is to observe the effects of the vitamin K supplements on the carboxylation of serum osteocalcin in postmenopausal women. Twenty-four healthy postmenopausal women were recruited for the double-blind controlled study. Before and after daily administration of 1.0mg of phylloquinone for one month, the levels of serum vitamin K, osteocalcin, undercarboxylated osteocalcin were measured. Daily intake of vitamin K was also calculated. After the 4-weeks of supplements of 1.0mg/day of vitamin K, there were no significant differences for the levels of serum vitamin K, osteocalcin, and ucOC between the experimental and placebo groups. In this study, it was not found that the supplements of vitamin K to the postmenopausal women had any positive effects on.

• 한국전기전자재료학회논문지
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• 제20권10호
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• pp.878-882
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• 2007

Carboxylated multi-walled carbon nanotubes (MWNTs) were in detail characterized by XRD, XPS, FTIR, and thermogravimetric measurements. Carboxylic acid groups were functionalized to MWNTs under aqueous acid condition. The changes of sonication and reflux conditions rarely influenced the degree of carboxylation on MWNTs, but decreased the thermal stability of the resultant carboxylated MWNTs. XRD results showed that the diffraction peaks (100), (101), and (102) of pristine MWNTs disappeared after acid treatment, but the diffraction peak (002) was Preserved in the carboxylated MWNTs. The introduction of carboxylic acid groups on MWNTs caused to improve the dispersibility of the resultant carboxylated MWNTs in water.

• Bulletin of the Korean Chemical Society
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• 제34권2호
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• pp.565-568
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• 2013

Acetyl-CoA carboxylases (ACCs) play critical roles in fatty acid synthesis and oxidation by the catalytic activity of the carboxylation of acetyl-CoA to malonyl-CoA. It is known that ACCs are inactivated through reversible phosphorylation by AMP-activated protein kinase (AMPK) and allosterically activated by citrate. Here, we determined the crystal structures of biotin carboxylase (BC) domain of human ACC2 phosphorylated by AMPK in the presence of citrate in order to elucidate the activation mechanism by citrate. This structure shows that phosphorylated Ser222 is released from the dimer interface, and thereby facilitating the dimerization or oligomerization of the BC domain allosterically. This structural explanation is coincident with the experimental result that the phosphorylated Ser222 was dephosphorylated more easily by protein phosphatase 2A (PP2A) as the citrate concentration increases.

• 한국치위생학회지
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• 제11권4호
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• pp.419-426
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• 2011

Originally, vitamin K was defined as a factor for blood coagulation. Now more attention is focused on vitamin K for bone metabolism and bone health. Vitamin K is a coenzyme for glutamate carboxylase which converts glutamate residues to ${\gamma}$-carboxyglutamate(Gla) residues. Gla residues have calcium binding ability and bound to hydroxyapatite crystals in bone. Vitamin K promotes the carboxylation of osteocalcin and matrix Gla-protein, vitamin K-dependent proteins and improves bone mineral density and bone mass. Vitamin K deficiency causes reductions in bone mineral density and increases the risk of osteoporotic bone fractures, resulting from undercarboxylated osteocalcin. This paper is to provide a brief information of vitamin K and its role in bone health.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.63-63
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• 2007

Carboxylated multi-walled carbon nanotubes (MWNTs) were in detail characterized by XRD, XPS, FTIR, and thermogravimetric measurements. Carboxylic acid groups were functionalized to MWNTs using aqueous acid solutions. The change. of sonication and reflux conditions rarely influenced the degree of carboxylation on MWNTs, but reduced the thermal stability of the resulting carboxylated MWNTs. The characteristic Bragg peaks of pristine and carboxylated MWNTs were analyzed by XRD measurements. After acid treatment the diffraction peaks (100), (101), and (102) of pristine MWNTs disappeared, but the diffraction peak (002) was preserved in the carboxylated MWNTs. The introduction of carboxylic acid groups on MWNTs caused to improve the dispersibility of the resulting carboxylated MWNTs in water.

• 운동영양학회지
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• 제16권1호
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• pp.1-9
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• 2012

Long chain fatty acids (LCFAs) are transported into cells via plasma transporters, are activated to fatty acyl-CoA by fatty acyl-CoA synthase (ACS), and enter mitochondria via the carnitine system (CPT1/CACT/CPT2). The mitochondrial carnitine system plays an obligatory role in β-oxidation of LCFAs by catalyzing their transport into the mitochondrial matrix. Fatty acyl-CoAs are oxidized via the β-oxidation pathway, which results in the production of acetyl-CoA. The acetyl-CoA can be imported into the tricarboxylic acid (TCA) cycle for oxidation in the mitochondrial matrix or can be used for malonyl-CoA synthesis by acetyl-CoA carboxylase 2 (ACC2) in the cytoplasm. In skeletal muscle, ACC2 catalyzes the carboxylation of acetyl-CoA to form malonyl-CoA, which is a potent endogenous inhibitor of carnitine palmitoyltransferase 1 (CPT1). Thus, ACC2 indirectly inhibits the influx of fatty acids into the mitochondria. Fatty acid metabolism can also be regulated by malonyl-CoA-mediated inhibition of CPT1.

• 한국산림과학회지
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• 제96권5호
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• pp.551-560
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• 2007

We investigated physiological damages and biochemical alleviation of five species of genus Acer under ozone fumigation in order to assess their tolerant ability against ozone toxicity. At the end of 150 ppb $O_3$ fumigation, photosynthetic characteristics were measured, and chlorophyll contents, malondialdehyde (MDA) and antioxidative enzyme activities were analyzed in the leaves of five maple trees (Acer buergerianum, A. ginnala, A. mono, A. palmatum, and A. palmatum var. sanguineum). The reduction of chlorophyll (chl) a in ozone-exposed plants was 16.8% (A. buergerianum) to 26.7% (A. ginnala) of control plants. For the content of chi b, A. ginnala and A. palmatum var. sanguineum represented the high reduction of 26.3% and 23.6%, respectively. The highest reduction on the chi a:b ratio was observed in the leaves of A. palmatum. The reduction of net photosynthesis in five species varied from 2.4% to 37.6%. Among five species, A. ginnala showed remarkable reduction (37.6%) for net photosynthesis in comparison with control. Carboxylation efficiency differed significantly (P < 0.05) among species and between control and ozone treatment. The reduction of carboxylation efficiency was the highest in the leaves of A. ginnala (44.7%). A. palmatum var. sanguineum showed the highest increase (41.7%) for MDA content. The highest increase of superoxide dismutase (SOD) activity represented in A. palmatum (26.1%) and the increase of ascorbate peroxidase (APX) activity ranged from 16.5% (A. ginnala) to 49.1% (A. palmatum var. sanguineum). A. mono showed the highest increase (376.6%) of glutathione reductase (GR) activity under ozone fumigation and A. buergerianum also represented high increase (42.3%) of GR activity. Catalse (CAT) activity increased in the leaves of A. ginnala, A. palmatun and A. palmatum var. sanguineum under ozone exposure, whereas A. buergerianum and A. mono decreased in comparison with control plants. In conclusion, physiological markers such as chlorophyll content and photosynthesis that responded sensitively to $O_3$ in maple trees were considered as the very important indicators in order to evaluate the tolerance against $O_3$ stress, and parameters were closely related with each other. Among anti oxidative enzymes, SOD and APX might be contributed to alleviate to $O_3$ toxicity through the increase of activity in all maple trees. Therefore, these compounds can be used as a biochemical maker to assess the stress tolerance to $O_3$.

• 한국산림과학회지
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• 제97권5호
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• pp.508-515
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• 2008

Sycamore (Platanus occidentalis L.) seedlings were grown under low light intensity and ozone treatments to investigate the role of the light environment in their response to chronic ozone stress. One-year-old seedlings of Platanus occidentalis L. were grown in pots for 3 weeks under low light (OL, $150{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) and high light (OH, $300{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) irradiance in combination with 150 ppb of ozone fumigation. After three weeks of ozone and light treatment, seedlings were placed in ozone free clean chamber for 3 weeks for recovery from ozone stress with same light conditions to compare recovery capacity. Ozone fumigation determined an impairment of the photosynthetic process. Reduction of leaf dry weight (14%) and shoo/root ratio (17%) were observed in OH treatment. OL treatment also showed severe reductions in leaf dry weight and shoot/root ratio by 48% and 36% comparing to control, respectively. At the recovery phase, OH-treated plants recovered their biomass, whereas OL-treated plant showed reduction in leaf dry weight (52%) and shoot/root ratio (49%). OH-treated plants reached similar relative growth rate (RGR) comparing to control, whereas OL-treated plants showed lower RGR in stem height. However, there were no significant differences in response to those treatments in stem diameter RGR at the recovery phase. Ozone treatment produced significant reduction of net photosynthesis in both high and low light treatments. Carboxylation efficiency and apparent quantum yield in OL-treated plants showed significant reductions rate to 10% and 45%, respectively. At the recovery stage, ozone exposed seedlings under high light had similar photosynthetic capacity comparing to control plants. Antioxidant enzymes activities such as superoxide dismutase (SOD), ascorbate peroxidase (APX), and glutathione reductase (GR) were increased in ozone fumigated plants only under low light. The present work shows that the physiological changes occur in photosynthesis-related parameters and growth due to ozone and low light stress. Thus, low light seems to enhance the detrimental effects of ozone on growth, photosynthesis, and antioxidant enzyme responses.

• 한국농림기상학회지
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• 제10권2호
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• pp.47-57
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• 2008

오존에 노출된 참나무속 5종의 오존에 대한 내성 능력을 평가하기 위하여 생리생화학적 변화를 조사하였다. 150ppb 오존에 노출된 참나무속 5종(상수리나무, 갈참나무, 대왕참나무, 졸참나무, 굴참나무)의 잎에서 엽록소 함량, 광합성 특성, MDA 함량 및 항산화효소 활성이 측정되었다. 엽록소, 카로테노이드 함량, 순광합성 속도 및 탄소고정효율은 오존 처리 후에 감소하였다. 오존에 노출된 수목의 총 엽록소 함량과 탄소고정효율의 감소율은 갈참나무의 경우 15%와 34% 였으며, 굴참나무의 경우 38.3%와 62.1%였다. MDA 함량은 오존 처리 하에서 증가하였으며, 상수리나무에서 140%까지 증가를 보였다. 상수리나무의 SOD 활성 증가율(60%)은 가장 높았으며, APX 활성은 굴참나무, 졸참나무, 상수리나무에서 증가를 보였다. 생리생화학적 반응을 기초로 한 참나무속 5종의 내성 능력은 갈참나무, 대왕참나무, 졸참나무, 굴참나무, 상수리나무 순이었다. 결론적으로 엽록소 함량, 광합성 특성, MDA 함량, 항산화효소와 같은 생리학적 지표들은 오존 스트레스에 대한 내성을 평가하기 위한 매우 중요한 지표들로 생각되며, 이러한 모수들은 서로 밀접한 관계를 가진다.

• 한국작물학회지
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• 제33권4호
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• pp.353-359
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• 1988

두께가 서로 다른 $C_3$ 식물의 잎은 단위엽면적당 광합성 능력에 있어서도 차이가 나는 바 잎의 내부구조와 기체교환 사이의 관계를 바탕으로 그 원인을 구명하였다. 광합성의 2대 제한요인으로 기체확산과 생화학적 과정의 상대적인 중요도를 결정하기 위해 중엽세포의 표면은 기체확산 저항의, 그리고 세포의 체적은 탄소고정 능력의 지표로 가정하였다. 즉 세포의 표면적이 증가하면 이산화탄소의 액상확산 저항이 감소하며 체적이 증대되면 carboxylation, oxygenation, 그리고 dark respiration 반응속도가 증가한다고 간주하였다. 이러한 개념을 함축하는 광합성 모형을 작성하고 이 가설의 검증을 위해 대두 품종 Amsoy잎을 이용한 실험을 수행하였다. 생장조절실내에서 200, 400, 600$\mu$mol photons m$^{-2}$ s$^{-1}$ PAR을 공급하여 서로 다른 두께의 잎을 준비하였으며 제3 및 4본엽에 대해 1,000 $\mu$mol photons m$^{-2}$ s$^{-1}$ PAR 및 28 기온 환경하에서 이산화탄소 흡수속도를 측정한 결과 세포의 체적과 표면적의 영향을 동시에 고려한 광합성 모형이 세포 표면적만을 고려한 경우 보다 실측치에 가까운 예측치를 산출하였다. 이로 미루어 세포의 표면적과 체적은 잎의 두께 및 그에 따른 광합성 능력의 예측에 적절한 변수로 간주된다.