• Asian-Australasian Journal of Animal Sciences
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• 제10권4호
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• pp.335-356
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• 1997

Injection of bovine growth hormone (bGH) to lactating dairy cows increases milk yield and yields of milk components including fat. It is generally believed that most of the anabolic effects derived from bGH in animal tissues are primarily mediated by IGF-1. IGF-1 is a strong anabolic peptide in the plasma of animals and exerts mitogenic and metabolic effects on target cells. Contrary to most protein hormones, the majority of IGF-1 in circulation is bound to the binding proteins (IGFBPs) which are known to be responsible for modifying the biological actions of IGF-1, thus making determinations of IGF-1 actions more difficult. On the other hand, fat is a major milk component and the greatest energy source in milk. Currently, the fat content of milk is one of the major criteria used in determining milk prices. It has been known that flavor and texture of dairy products are mainly affected by milk fat and its composition. Acetyl-CoA carboxylase (ACC) is the rate limiting enzyme which catalyzes the conversion of acetyl-CoA to malonyl-CoA for fatty acid synthesis in 1ipogenic tissues of animals including bovine lactating mammary glands. In addition to the short-tenn hormonal regulation of ACC by changes in the catalytic efficiency per enzyme molecule brought about by phosphorylation and dephosphorylation of the enzyme, the long-term hormonal regulation of ACC by changes in the number of enzyme molecules plays an essential role in control of ACC and lipogenesis. Insulin, at supraphysiological concentrations, binds to IGF-1 receptors, thereby mimicking the biological effects of IGF-1. The receptors for insulin and IGF-1 share structural and functional homology. Furthermore, epidermal growth factor increased ACC activity in rat hepatocytes and adipocytes. Therefore, it can be assumed that IGF-1 mediating bGH action may increase milk fat production by stimulation ACC with phosphorylation (short term) and/or increasing amounts of the enzyme proteins (long term). Consequently, the main purpose of this paper is to give the readers not only the galactopoietic effects of bGH, but also the insight of bGH action with regard to stimulating milk fat synthesis from the whole body to the molecular levels.

• Korean Chemical Engineering Research
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• 제47권6호
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• pp.700-704
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• 2009

GTL(gas-to-liquid) 합성유 제조용 SCR(steam carbon dioxide reforming) 공정의 시뮬레이션 연구를 수행하였다. 온도 및 $CH_4/steam/CO_2$ 반응물 비와 같은 변수를 바꾸어 가면서 SCR 공정을 위한 최적 운전조건을 살펴보았다. 공정 시뮬레이션을 위해 Aspen Plus를 사용하였다. 또한 정상상태 가정하의 열역학적 물성치 계산을 위해 Aspen Plus의 RSK (Redlich-Kwong-Soave) 상태방정식을 사용하였다. FT 공정을 위한$H_2/CO$ 비, $CH_4$ 전환율, $CO_2$ 전환율을 살펴봄으로써 최적의 온도와 최적의 반응물 비를 결정하였다. 시뮬레이션 결과, SCR reformer 촉매층 출구 최적온도는 상압에서 $850^{\circ}C$ 였으며, 이 온도에서 $CH_4$ 전환율은 99%, $CO_2$ 전환율은 49%로 계산되었고, $CH_4/steam/CO_2$ 최적 반응물 비율은 1.0/1.6/0.7로 나타났다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.108-109
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• 2013

Mitochondria play key roles in the production of cell's energy. Their dominant function is the synthesis of adenosine 5'-triphosphate (ATP) from adenosine diphosphate (ADP) and phosphate (Pi) through the oxidative phosphorylation. Evaluation of drug-induced mitochondrial toxicity has become increasingly important since mitochondrial dysfunction has recently been implicated in numerous diseases including cancer and diabetes mellitus. Mitochondrial functions have been monitored via oxygen consumption, mitochondrial membrane potential, and more importantly via ATP synthesis since ATP synthesis is the most essential function of mitochondria. Various analytical methods have been employed to investigate ATP synthesis in mitochondria, including high performance liquid chromatography (HPLC), bioluminescence technique, and pH measurement. However, most of these methods are based on destructive analysis or indirect monitoring through the enzymatic reaction. Infrared absorption spectroscopy (IRAS) is one of the useful techniques for real-time, label-free, and direct monitoring of biological reactions [1,2]. However, the strong water absorption requires very short path length in the order of several micrometers. Transmission measurements with thin path length are not suitable for mitochondrial assays because solution handlings necessary for evaluating mitochondrial toxicity, such as rapid mixing of drugs and oxygen supply, are difficult in such a narrow space. On the other hand, IRAS in the multiple internal reflection (MIR) geometry provides an ideal optical configuration to combine solution handling and aqueous-phase measurement. We have recently reportedon a real-time monitoring of drug-induced necrotic and apoptotic cell death using MIR-IRAS [3,4]. Clear discrimination between viable and damaged cells has been demonstrated, showing a promise as a label-free and real-time detection for cell-based assays. In the present study, we have applied our MIR-IRAS system to mitochondria-based assays by monitoring ATP synthesis in isolated mitochondria from rat livers. Mitochondrial ATP synthesis and hydrolysis were in situ monitored with MIR-IRAS, while dissolved oxygen level and solution pH were simultaneously monitored with O2 and pH electrodes, respectively. It is demonstrated that ATP synthesis and hydrolysis can be monitored by the IR spectral changes in phosphate groups in adenine nucleotides and MIR-IRAS is useful for evaluating time-dependent drug effects of mitochondrial toxicants.

• Bulletin of the Korean Chemical Society
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• 제33권5호
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• pp.1505-1508
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• 2012

Protein tyrosine phosphatase 1B (PTP1B) is a key factor in negative regulation of the insulin pathway, and is a promising target for the treatment of type-II diabetes, obesity and cancer. Herein, compound ($\mathbf{4}$) was first observed to have moderate inhibitory activity against PTP1B with an $IC_{50}$ value of $13.72{\pm}1.53{\mu}M$. To obtain more potent PTP1B inhibitors, we synthesized a series of chalcone derivatives using compound ($\mathbf{4}$) as the lead compound. Compound $\mathbf{4l}$ ($IC_{50}=3.12{\pm}0.18{\mu}M$) was 4.4-fold more potent than the lead compound $\mathbf{4}$ ($IC_{50}=13.72{\pm}1.53{\mu}M$), and more potent than the positive control, ursolic acid ($IC_{50}=3.40{\pm}0.21{\mu}M$). These results may help to provide suitable drug-like lead compounds for the design of inhibitors of PTP1B as well as other PTPs.

• Applied Biological Chemistry
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• 제27권4호
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• pp.238-244
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• 1984

Kluyveromyces fragilis No.351을 이용하여 이눌라아제 생산을 최대로 할수있는 배지 조성 및 배양 조건을 조사하였다. 탄소원 및 inducer로는 돼지감자 추출액을 이용하였으며 전체 중량 3.5%가 가장 적합하였다. 일반적으로 많이 이용되는 유기 질소원인 yeast extract보다 bactocasitone이 더 좋았고 2.0%에서 효소 생성이 최대로 되었다. 초기 pH 5.5 및 $30^{\circ}C$가 알맞은 배양조건이었으며, $NH_4H_2PO_4$ 0.5% 첨가로 효소 생성이 증가되었다. 이눌라아제의 생성은 통기를 높여감에 따라 더욱 많이 생성되었고 intracellular inulase의 생성은 균체증식에 비례하여 증가되었다. Ultrafiltration과 에탄올 침전법을 이용하여 효소를 회수한 결과 72%의 수율을 얻을 수 있었다.

• 한국식물학회:학술대회논문집
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• 한국식물학회 1999년도 제13회 식물생명공학심포지움 New Approaches to Understand Gene Function in Plants and Application to Plant Biotechnology
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• pp.63-67
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• 1999

We have isolated more than a dozen cDNA clones corresponding to genes that were expressed in Arabidopsis leaves when they were kept in the dark. The nucleotide sequence analysis showed that some of the clones encoded proteins with significant homology to $\beta$-glucosidase (din2), branched-chain $\alpha$-keto acid dehydrogenase subunit E1$\beta$(din3), and another subunit E2 (din4), yeast RAD23 (din5), asparagine synthetase (din6), pre-mRNA splicing factor SRp35 (din7), phosphomannose isomerase (din9), seed imbibition protein (din10), and 2-oxoacid-dependent oxidase (din11). Accumulation of transcripts from din3,4,6 and 10 occurred rapidly after the plants were transferred to darkness. Transcripts from din2,9, and 11 could be detected only after 24 h of dark treatment. Inhibition of photo-synthesis by DCMU strongly induced the accumulation of transcripts from those genes, and application of sucrose to detached leaves suppressed the accumulation both in the dark and by DCMU. These observations indicate that expression of the genes is caused by sugar starvation resulted from the cessation of photosynthesis. We further showed that din2-encoded protein also accumulated in senescing leaves. Given these results, possible roles of din genes in leaves in the dark and senescing leaves are discussed.

• 한국해양바이오학회지
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• 제8권2호
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• pp.45-53
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• 2016

Most of microalgae shift their metabolic pathways toward the fatty acid biosynthesis following nitrogen deprivation. Recent studies on Nannochloropsis species, oleaginous microalgae, have been performed to investigate the regulation of contents and compositions of fatty acids under stressful condition. The objective of this experiment is to identify the effect of nitrogen on cell growth and fatty acids production in Nannochloropsis oculata K-1281 and compare fatty acid composition response to nitrogen deficiency between N. oculata LB2164 and K-1281. The fatty acids content in N. oculata K-1281 was increased up to 210%, while the growth rate was decreased under nitrogen deficient condition. The contents of C16:0 and C16:1 increased dramatically in both N. oculata K-1281 and LB2164, while the contents of C20:4 and C20:5 increased in N. oculata LB2164. The fatty acids content and composition in N. oculata K-1281 returned following addition of nitrogen after nitrogen starvation. These results demonstrated that fatty acid contents and compositions under nitrogen deficiency will provide the understanding of fatty acid synthesis in microalgae.

• 대한화장품학회지
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• 제34권3호
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• pp.183-188
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• 2008

미백제를 선발하기 위해 주로 사용하는 현재의 방법은 in vitro 타이로시네이즈 활성 및 항산화능을 측정하는 것이다. 이 결과에 기초하여 다음 단계인 멜라노사이트에서의 멜라닌 생성량을 측정한다. 세포 내의 멜라닌 생성량 측정 법은 시간, 인력 및 숙련도가 요구된다. 따라서 초기 선발 방법의 신뢰성이 중요하다. 200개 중국시료 중 측정범위 내에서 세포독성이 없는 34개를 대상으로 세포 내 멜라닌량, 타이로시네이즈 활성, 항산화능의 상관관계를 조사하였다. 조사결과 직선의 상판관계를 확인할 수 없었다. 이 결과는 현재 선발방법의 한계 및 새로운 방법이 필요함을 보여주었다.

• Molecules and Cells
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• 제45권8호
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• pp.537-549
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• 2022

Preproenkephalin (PPE) is a precursor molecule for multiple endogenous opioid peptides Leu-enkephalin (ENK) and Met-ENK, which are involved in a wide variety of modulatory functions in the nervous system. Despite the functional importance of ENK in the brain, the effect of brain-derived factor(s) on PPE expression is unknown. We report the dual effect of neural epidermal growth factor (EGF)-like-like 2 (NELL2) on PPE gene expression. In cultured NIH3T3 cells, transfection of NELL2 expression vectors induced an inhibition of PPE transcription intracellularly, in parallel with downregulation of protein kinase C signaling pathways and extracellular signal-regulated kinase. Interestingly, these phenomena were reversed when synthetic NELL2 was administered extracellularly. The in vivo disruption of NELL2 synthesis resulted in an increase in PPE mRNA level in the rat brain, suggesting that the inhibitory action of intracellular NELL2 predominates the activation effect of extracellular NELL2 on PPE gene expression in the brain. Biochemical and molecular studies with mutant NELL2 structures further demonstrated the critical role of EGF-like repeat domains in NELL2 for regulation of PPE transcription. These are the first results to reveal the spatio-specific role of NELL2 in the homeostatic regulation of PPE gene expression.

• 한국가축번식학회지
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• 제26권4호
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• pp.361-368
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• 2002

The onset of pronucleus formation and DNA synthesis in porcine oocytes following the injection of porcine or murine sperm was determined in order to obtain insights into species-specific paternal factors that contribute to fertilization. After 44h in vitro maturation, spermatozoa was injected into the cytoplasm of oocytes. After injection, all oocytes were transferred to NCSU23 medium and cultured at 39'E under 5% CO2 in air. Similar frequencies of oocytes with female pronuclei were observed after injection with porcine sperm or with murine sperm. In contrast, male pronuclei formed 8 to 9 h following the injection of porcine sperm, and 6 to 8 h following the injection of murine sperm. After pronucleus formation maternally derived microtubules were assembled and appeared to move both male and female pronuclei to the oocyte center. A few porcine oocytes entered metaphase 22 h after the injection of murine sperm, but normal cell division was not observed. The mean time of onset of S-phase in male pronuclei was 9.7 h following porcine sperm injection and 7.4 h following mouse sperm injection. These results suggested that DNA synthesis was delayed in both pronuclei until the sperm chromatin fully decondensed, and the sperm nuclear decondensing activity and microtubule nucleation abilities of the male centrosome are cell cycle dependent.