• Title/Summary/Keyword: ACS

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Gene Targeting of the Acyl-CoA Synthetase Specific to Arachidonate

  • Kang, Man-Jong
    • Proceedings of the KSAR Conference
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    • 2000.10a
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    • pp.3-4
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    • 2000
  • The synthesis of acyl-CoA catalyzed by acyl-CoA synthetase (ACS, EC 6.2.1.3) from fatty acid, ATP, and CoA is a crucial reaction in mammalian fatty acid metabolism. In arachidonate metabolism, acyl-CoA synthetase(ACS) plays a key role in the esterification of free arachidonate into membrane phospholipids. Following its release by the action of calcium dependent phospholipase, free arachidonate is believed to be rapidly converted to arachidonoyl-CoA and reesterified into phospholipids in order to prevent excessive synthesis of eicosanoids. In previous studies, we have characterized five ACSs (designated as ACS1-5) with different tissue distribution. ACS1, ACS2, and ACS5 are similar in structure and fatty acid preference, and completely different from ACS3 and ACS4. The latter are arachidonate-preferring enzymes closely related in structure but expressed in different tissues: ACS3 mRNA is highly expressed in the brain and the mRNA for ACS4 is expressed in steroidogenic tissues including adrenal gland, ovary, and testis. To learn more about the potential function of ACS4 in arachidonate metabolism, we have produced knock-out mice for ACS4 gene. ACS4+/- females become pregnant less frequently and produce small litters with extremely low transmission of the disrupted alleles. Striking morphological changes including extremely enlarged uterine filled with numerous proliferative cysts of various size were detected in ACS4+/- females. Furthermore, marked accumulation of prostaglandins were seen in the uterus of heterozygous females. These results indicate that ACS4 is critical for the uterine arachidonate metabolism and heterozygous disruption of its gene lead to impaired pregnancy.

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Influence of Heating Rate and Temperature on Carbon Structure and Porosity of Activated Carbon Spheres from Resole-type Phenolic Beads

  • Singh, Arjun;Lal, Darshan
    • Carbon letters
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    • v.10 no.3
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    • pp.181-189
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    • 2009
  • Activated carbon spheres (ACS) were prepared at different heating rates by carbonization of the resole-type phenolic beads (PB) at $950^{\circ}C$ in $N_2$ atmosphere followed by activation of the resultant char at different temperatures for 5 h in $CO_2$ atmosphere. Influence of heating rate on porosity and temperature on carbon structure and porosity of ACS were investigated. Effect of heating rate and temperature on porosity of ACS was also studied from adsorption isotherms of nitrogen at 77 K using BET method. The results revealed that ACS have exhibited a BET surface area and pore volume greater than $2260\;m^2/g$ and $1.63\;cm^3/g$ respectively. The structural characteristics variation of ACS with different temperature was studied using Raman spectroscopy. The results exhibited that amount of disorganized carbon affects both the pore structure and adsorption properties of ACS. ACS were also evaluated for structural information using Fourier Transform Infrared (FTIR) Spectroscopy. ACS were evaluated for chemical composition using CHNS analysis. The ACS prepared different temperatures became more carbonaceous material compared to carbonized material. ACS have possessed well-developed pores structure which were verified by Scanning Electron Microscopy (SEM). SEM micrographs also exhibited that ACS have possessed well-developed micro- and meso-pores structure and the pore size of ACS increased with increasing activation temperature.

Molecular Characterization of an Arachidonate Preferring Acyl-CoA Synthetase, ACS4

  • Jo, Yong-Yeon
    • 대한생식의학회:학술대회논문집
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    • 2001.03a
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    • pp.213-216
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    • 2001
  • 본 연구에 의해 Arachidonoyl-CoA synthetase (ACS4)에 관하여 이하의 것을 증명하였다. 1. Moues ACS4 cDNA와 단백질을 분석한 결과 뇌에 특이적으로 발현하는 새로운 78 kDa의 ACS4 분자종을 발견하였다. 2. Steroid 생산세포에서 ACS4는 cAMP와 AA에 의해 유도되는 것을 증명하였다. 3. ACS4의 결손은 웅성 반성접합체에서 외견, 성장, 행동, 생식에 영향을 주지 않지만, 자성 이형접합체에서는 자궁내막의 비후와 낭포 (cyst)를 발생시켜 자궁기능을 저하시키는 것을 입증하였다. 4. ACS4는 자궁내막의 발생과 황체의 퇴화과정에서 중요한 역할을 담당하는 것으로 사료된다.

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Isolation and Characterization of ACC Synthase Gene Family in Mung Bean (Vigna radiata L.): Differential Expression of the Three ACC Synthase enes in Response to Auxin and Brassinosteroid

  • Sunjoo Joo;Kim, Woo-Taek
    • Journal of Plant Biotechnology
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    • v.2 no.2
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    • pp.61-71
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    • 2000
  • By screening a cDNA library of auxin-treated mung bean (Vigna radiata L.) hypocotyls, we have isolated two full-length cDNA clones, pVR-ACS6 and pVR-ACS7, for 1-aminocyclopropane-1-carboxylate (ACC) synthase, the rate-limiting enzyme in the ethylene biosynthetic pathway. While PVR-ACS6 corresponds to the previously identified PCR fragment pMBA1, pVR-ACS7 is a new cDNA clone. A comparison of deduced amino acid sequences among auxin-induced ACC synthases reveal that these enzymes share a high degree of homology (65-75%) to VR-ACS6 and VR-ACS7 polypeptides, but only about 50% to VR-ACS1 polypeptide. ACS6 and ACS7 are specifically induced by auxin, while ACS1 is induced by cycloheximide, and to lesser extent by excision and auxin treatment. Results from nuclear run-on transcription assay and RNA gel blot studies revealed that all three genes were transcriptionally active displaying unique patterns of induction by IAA and various hormones in etiolated hypocotyls. Particularly, 24-epibrassinolide (BR), an active brassinosteroid, specifically enhanced the expression of VR-ACS7 by distinct temporal induction mechanism compared to that of IAA. In addition, BR synergistically increased the IAA-induced VR-ACS6 and VR-ACS7 transcript levels, while it effectively abolished both the IAA- and kinetin-induced accumulation of VR-ACS1 mRNA. In light-grown plants, VR-ACS1 was induced by IAA in roots, whereas W-ACS6 in epicotyls. IAA- and BR-treatments were not able to increase the VR-ACS7 transcript in the light-grown tissues. These results indicate that the expression of ACC synthase multigene family is regulated by complex hormonal and developmental networks in a gene- and tissue-specific manner in mung bean plants. The VR-ACS7 gene was isolated, and chimeric fusion between the 2.4 kb 5'-upstream region and the $\beta$-glucuronidase (GUS) reporter gene was constructed and introduced into Nicotiana tobacum. Analysis of transgenic tobacco plants revealed the VR-ACS7 promoter-driven GUS activity at a highly localized region of the hypocotyl-root junction of control seedlings, while a marked induction of GUS activity was detected only in the hypocotyl region of the IAA-treated transgenic seedlings where rapid cell elongation occurs. Although there was a modest synergistic effect of BR on the IAA-induced GUS activity, BR alone failed to increase the GUS activity, suggesting that induction of VR-ACS7 occurs via separate signaling pathways in response to IAA and BR.

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New Insights into the Protein Turnover Regulation in Ethylene Biosynthesis

  • Yoon, Gyeong Mee
    • Molecules and Cells
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    • v.38 no.7
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    • pp.597-603
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    • 2015
  • Biosynthesis of the phytohormone ethylene is under tight regulation to satisfy the need for appropriate levels of ethylene in plants in response to exogenous and endogenous stimuli. The enzyme 1-aminocyclopropane-1-carboxylic acid synthase (ACS), which catalyzes the rate-limiting step of ethylene biosynthesis, plays a central role to regulate ethylene production through changes in ACS gene expression levels and the activity of the enzyme. Together with molecular genetic studies suggesting the roles of post-translational modification of the ACS, newly emerging evidence strongly suggests that the regulation of ACS protein stability is an alternative mechanism that controls ethylene production, in addition to the transcriptional regulation of ACS genes. In this review, recent new insight into the regulation of ACS protein turnover is highlighted, with a special focus on the roles of phosphorylation, ubiquitination, and novel components that regulate the turnover of ACS proteins. The prospect of cross-talk between ethylene biosynthesis and other signaling pathways to control turnover of the ACS protein is also considered.

An Efficient ACS Architecture for radix-4 Viterbi Decoder (Radix-4 비터비 디코더를 위한 효율적인 ACS 구조)

  • Kim Deok-Hwan;Rim Chong-Suck
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.42 no.1
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    • pp.69-77
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    • 2005
  • The Viterbi decoder which is used for the forward error correction(FEC) is a crucial component for successful modern communication systems. As modern communication speed rapidly high, the development of high speed communication module is important. However, since the feedback loop in ACS operation, high speed of Viterbi decoder is very difficult. In this paper, we propose an area reduced, high speed ACS Architecture of Viterbi decoder based on the radix-4 architecture. The area is reduced by rearranging the ACS operations, and the speed is improved by retiming of path metric memory. The proposed ACS architecture of Viterbi decoder is implemented in VHDL and synthesized in Xilinx ISE 6.2i. The area-time product of the proposed architecture is improved by 11% compared to that of the previous high speed radix-4 ACS architecture.

Molecular Characterization of a Transient Expression Gene Encoding for 1-Aminocyclopropane-1-carboxylate Synthase in Cotton (Gossypium hirsutum L.)

  • Wang, Xia;Zhang, Ying;Zhang, Jiedao;Cheng, Cheng;Guo, Xingqi
    • BMB Reports
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    • v.40 no.5
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    • pp.791-800
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    • 2007
  • Ethylene performs an important function in plant growth and development. 1-aminocyclopropane-1-carboxylate (ACC) synthase (ACS), the key enzyme involved in ethylene biosynthesis, has been the focus of most ethylene studies. Here, a cotton ACS gene referred to as Gossypium hirsutum ACS1 (GhACS1), was isolated. The full-length cDNA of GhACS1 encodes for a 476-amino acid protein which harbors seven conserved regions, 11 invariant amino acid residues, and the PLP binding active site, all of which characterize ACC synthases. Alignment analysis showed that GhACS1 shared a high degree of identity with other known ACC synthases from different species. Two introns were detected in the genomic DNA sequence, and the results of Southern blot analysis suggested that there might be a multi-gene family encoding for ACC synthase in cotton. From the phylogenetic tree constructed with 24 different kinds of ACC synthases, we determined that GhACS1 falls into group II, and was closely associated with the wound-inducible ACS of citrus. The analysis of the 5' flanking region of GhACS1 revealed a group of putative cis-acting elements. The results of expression analysis showed that GhACS1 displayed its transient expression nature after wounding, abscisic acid (ABA), and $CuCl_2$ treatments. These results indicate that GhACS1, which was transiently expressed in response to certain stimuli, may be involved in the production of ethylene for the transmission of stress signals.

Efficient Path Search Method using Ant Colony System in Traveling Salesman Problem (순회 판매원 문제에서 개미 군락 시스템을 이용한 효율적인 경로 탐색)

  • 홍석미;이영아;정태충
    • Journal of KIISE:Software and Applications
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    • v.30 no.9
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    • pp.862-866
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    • 2003
  • Traveling Salesman Problem(TSP) is a combinational optimization problem, Genetic Algorithm(GA) and Lin-Kernighan(LK) Heuristic[1]that is Local Search Heuristic are one of the most commonly used methods to resolve TSP. In this paper, we introduce ACS(Ant Colony System) Algorithm as another approach to solve TSP and propose a new pheromone updating method. ACS uses pheromone information between cities in the Process where many ants make a tour, and is a method to find a optimal solution through recursive tour creation process. At the stage of Global Updating of ACS method, it updates pheromone of edges belonging to global best tour of created all edge. But we perform once more pheromone update about created all edges before global updating rule of original ACS is applied. At this process, we use the frequency of occurrence of each edges to update pheromone. We could offer stochastic value by pheromone about each edges, giving all edges' occurrence frequency as weight about Pheromone. This finds an optimal solution faster than existing ACS algorithm and prevent a local optima using more edges in next time search.

Functional Studies of Acyl-CoA Synthetase 4 in the Rat Liver (흰쥐 간장에 있어서 아실-CoA 합성효소4의 기능연구)

  • 정영희;문승주;강만종
    • Journal of Nutrition and Health
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    • v.36 no.4
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    • pp.376-381
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    • 2003
  • Acyl-CoA synthetase 4 (ACS4) is an arachidonate-preferring enzyme abundant in steroidogenic tissues. We examined ACS4 in rat liver, which contains a variety of pathways that use acyl-CoAs, in order to determine subcellular locations. We demonstrate that ACS4 protein was present most abundantly in the mitochondria and to a much lesser extent in the peroxisomes and microsomes. To determined the dietary effects on the level of ACS4 mRNA, northern blotting was carried out using total RNA from the livers of adult male rats fed various diets. Fasting, high fat diet, and fat-free high sucrose diet increased the hepatic level of ACS4 mRNA approximately 2-fold. Furthermore, the levels of ACS4 mRNA were induced by DEHP[Di- (2-ethylhexyl) phthalate]. These data suggest that ACS4 expression in the liver is regulated with a variety of pathways, including $\beta$-oxidation, hormone, and insulin.

Antioxidant and antidiabetic effects of leaves and stems of Acanthopanax sieboldianum (Makino) Koidz (오가나무 잎, 줄기의 항산화 및 항당뇨 효능 분석)

  • Kim, Sang-Jun;Kim, Ji-Ae;Kim, Sol;Youn, Jong-Ung;Kim, Seok Hong;Han, Sang-Sub;Kim, Seon-Young;Jeong, Seung-Il
    • Korean Journal of Pharmacognosy
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    • v.50 no.2
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    • pp.141-147
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    • 2019
  • The aim of this study was to investigate the potential of Acanthopanax sieboldianum (Makino) Koidz (ACS) as a potent antioxidant and antidiabetic agent. The antioxidative and alpha-glucosidase inhibitory activities were examined using the methanol extracts and solvent fractions from ACS-leaf and ACS-stem. Antioxidative activities were measured by in vitro methods such as DPPH and ABTS radical scavenging activity and superoxide dismutase (SOD) activity. When the chloroform and ethyl acetate fractions of ACS-leaf and ethyl acetate fractions of ACS-stem were compared with the control, the SOD-like activity was impaired even at the low treatment concentrations. In addition, the ethyl acetate fractions of ACS-leaf and ACS-stem showed alpha-glucosidase inhibition activities at low treatment concentrations. Analysis of the major components in the fractions of ACS-leaf and ACS-stem was also performed using HPLC. Finally, astragalin, isoqurecetin, chlorogenic acid and caffeic acid contents were measured. Based on this work, we propose that ACS-leaf and ACS-stem have great potential as natural antioxidant and antidiabetic materials related to health benefits.