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Results 201 - 250 of 753
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Hiltunen J Kalervo - - 2010
The highly conserved fatty acid de novo synthesis pathway in mitochondria proceeds in an acyl carrier protein-dependent manner through a discrete set of enzymes. Saccharomyces cerevisiae has served as a model for studies of mitochondrial fatty acid synthesis type II (FAS II) and as a template for identification of mammalian ...
Petschnigg Julia - - 2009
Storage triacylglycerols (TAG) and membrane phospholipids share common precursors, i.e. phosphatidic acid and diacylglycerol, in the endoplasmic reticulum. In addition to providing a biophysically rather inert storage pool for fatty acids, TAG synthesis plays an important role to buffer excess fatty acids (FA). The inability to incorporate exogenous oleic acid ...
Schlegel Mark K - - 2009
An improved synthesis of glycol nucleic acids is reported using new phosphoramidite building blocks in which the exocyclic amino groups of adenine and guanine are protected as N-dimethylformamidines, whereas the amino group of cytosine is protected via an acetamide. Besides a more rapid synthesis with higher yields, these phosphoramidites allow ...
Carballeira Néstor M NM Department of Chemistry, University of Puerto Rico, San Juan, Puerto Rico 00931-3346. - - 2009
The first total synthesis for the (Z)-17-methyl-13-octadecenoic acid was accomplished in seven steps and in a 45% overall yield. The use of (trimethylsilyl)acetylene was key in the synthesis. Based on a previous developed strategy in our laboratory the best synthetic route towards the title compound was first acetylide coupling of ...
Zhou Yongqiang - - 2009
The objectives of this study were to investigate the protective effects of Eucommia ulmoides Oliv. (EUO) bark and leaf against cytotoxicity induced by amyloid-β peptide (Aβ) and to explore their active components. The PC-12 cells injury mediated by Aβ(25-35) was employed to assess the neuroprotective effects of EUO bark, EUO ...
Coggan Andrew R AR Division of Radiological Sciences, Cardiovascular Imaging Laboratory, Edward Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 South Kingshighway Boulevard, St. Louis, MO 63110, USA. - - 2009
The purpose of the present study was to assess the accuracy of rates of myocardial fatty acid esterification (MFAE) obtained using positron emission tomography (PET). Sixteen dogs were studied after an overnight fast (FAST), during a euglycemic hyperinsulinemic clamp (CLAMP), or during infusion of intralipid (IL) or IL plus dobutamine ...
Wang Chun - - 2009
Acetyl-CoA carboxylase-alpha (ACCA) is a rate-limiting enzyme in long chain fatty acid synthesis, playing a critical role in cellular energy storage and lipid synthesis. ACCA is upregulated in multiple types of human cancers and small interfering RNA-mediated ACCA silencing in human breast and prostate cancer cells results in oxidative stress ...
Zhang Mei - - 2009
In order to understand more details about the role of abscisic acid (ABA) in fruit ripening and senescence, six 740 bp cDNAs (LeNCED1, LeNCED2, PpNCED1, VVNCED1, DKNCED1 and CMNCED1) which encode 9-cis-epoxycarotenoid dioxygenase (NCED) as a key enzyme in ABA biosynthesis, were cloned from fruits of tomato, peach, grape, persimmon ...
Hawranik Drew J - - 2009
Usnic acid, a highly functionalized dibenzofuran, is a polyketide secondary metabolite produced by several species of lichens. Synthesis of usnic acid from commercially available starting material was accomplished in two steps. The synthesis involves the methylation of phloracetophenone followed by oxidation with horseradish peroxidase. This work will lay the foundation ...
Chen Mingjie - - 2009
Embryo-specific overexpression of biotin carboxyl carrier protein 2 (BCCP2) inhibited plastid acetyl-coenzyme A carboxylase (ACCase), resulting in altered oil, protein, and carbohydrate composition in mature Arabidopsis (Arabidopsis thaliana) seed. To characterize gene and protein regulatory consequences of this mutation, global microarray, two-dimensional difference gel electrophoresis, iTRAQ, and quantitative immunoblotting were ...
Jiang Xinglin - - 2009
Biobased platform chemicals have attracted growing interest recently. Among them, 3-hydroxypropionic acid receives significant attention due to its applications in the synthesis of novel polymer materials and other derivatives. To establish a biotechnology route instead of the problematic chemical synthesis of 3-hydroxypropionic acid, biosynthetic pathway is required, and the strategies ...
König Bettina - - 2009
Fibrates and thiazolidinediones, agonists of PPARa and PPARgamma, respectively, reduce triglyeride concentrations in rat liver and plasma. Fatty acid and triacylglycerol synthesis in mammals is regulated by sterol regulatory element-binding protein (SREBP)-1c. Recently, it was shown that insulin-induced gene (Insig)-1, the key regulator of SREBP activity, is up-regulation by both ...
Trygstad Timothy M - - 2009
Described is a flexible synthesis of the C3-C14 domain of 7-deoxyokadaic acid that is amenable to facile structural diversification. Treatment of ynone 10 under acidic conditions led to net bis-conjugate addition of the latent diol to give the thermodynamically favored spiroketal 27, a versatile intermediate, en route to 7-deoxyokadaic acid ...
Kang Segoo - - 2009
Highly ordered mesoporous SBA-15 silica particles with rodlike morphologies were synthetically controlled for the first time by adjusting hydrochloric acid concentration in the range of 0.1-5.0 M in the presence of block copolymer template under static condition but with no addition of inorganic salts. This work illustrates that it is ...
Ashari Siti Efliza - - 2009
Kojic acid monooleate is a fatty acid derivative of kojic acid which can be widely used as a skin whitening agent in a cosmetic applications. In avoiding any possible harmful effects from chemically synthesized product, the enzymatic synthesis appears to be the best way to satisfy the consumer demand nowadays. ...
Wu Xiaoxing - - 2009
An extremophilic challenge: Stereospecific condensation of a fully functionalized ketal aldehyde and a 2,6-dihydroxybenzoic acid is the key step in the synthesis of (-)-berkelic acid confirming Fürstner's reassignment of the stereochemistry at C18 and C19, establishing the absolute stereochemistry, and tentatively assigning the stereochemistry at C22.
Brown Lynda J - - 2009
A new approach to the synthesis of 2-fluoro-2-deoxy-d-glucose (FDG, [(19/18)F]-) is described, which employs supported perfluoroalkylsulfonate precursors , where the support consists of insoluble polystyrene resin beads. Treatment of these resins with [(19)F]fluoride ion afforded protected FDG [(19)F]- as the major product, and the identities of the main byproducts were ...
Miao FengPing - - 2008
The compositions and contents of astaxanthin esters and fatty acids in four types of Haematococcus pluvialis cells were studied by HPLC and GC-MS. Results showed that the synthesis and accumulation of astaxanthin was independent of the formation of cysts, but was highly correlated with the synthesis and accumulation of fatty ...
Zhang Wenbin - - 2009
An efficient method for enzymatic-selective synthesis of dilauryl mannoses was developed using lipase-catalyzed condensation of D: -mannose and lauric acid in a simultaneous reaction-extraction system. The highest equilibrium conversion of diesters of 51% (1,6-diester: 14%; 3,6-diester: 18%; 4,6-diester: 19%) and the total conversion of mono and dilauryl mannoses of 76% ...
Aubrey A D - - 2009
There is little consensus regarding the plausibility of organic synthesis in submarine hydrothermal systems (SHSs) and its possible relevance to the origin of life. The primary reason for the persistence of this debate is that most experimental high temperature and high-pressure organic synthesis studies have neglected important geochemical constraints with ...
Andersen Casper S - - 2009
We are presenting the synthesis of a phenylene ethynylene-based rod containing an Fmoc protected amino group and an activated acid which can be applied to peptide couplings. This linear amino acid analogue is applied to the synthesis of di-, tri- and pentamers. The pentamer has a molecular mass of 6.5 ...
Urata Hidehito - - 2008
The first chemical synthesis of two metabolites ((1R,2S,5R,6S)-6-(3,4-dihydroxyphenyl)-2-(3,4-methylenedioxyphenyl)-3,7-dioxabicyclo[3,3,0]octane (SC-1) and (1R,2S,5R,6S)-2,6-bis(3,4-dihydroxyphenyl)-3,7-dioxabicyclo[3,3,0]octane (SC-2)) of sesamin was achieved by a simple two-step approach from sesamin. The approach consists of acetoxylation of the methylenedioxy moiety(ies) with lead(IV) tetraacetate and acid hydrolysis of the resulting hemiorthoester to SC-1 and SC-2.
Pragani Rajan R Department of Chemistry, Scripps Florida, Jupiter, Florida 33458, - - 2008
A stereoselective synthesis of the model aglycone corresponding to the anti-HIV aureolic acids durhamycins A (1) and B (2) is described.
Abramova Tatiana V - - 2008
We propose the new approach to the synthesis of 5'-triphosphate derivatives of natural and modified dinucleotides with expanded functionality. Our strategy includes the combination of the solution phase synthesis of necessary dimers using the wide range of nucleic acids chemistry methods and the subsequent introduction of the triphosphate residue. A ...
Wang Chao - - 2008
Water soluble high quality CdTe nanocrystals (NCs) with mercaptosuccinic acid (MSA) as stabilizer are prepared by refluxing and hydrothermal synthesis in this paper. The MSA stabilizer which comprises both thioglycolic acid (TGA)-like and 3-mercaptopropionic acid (MPA)-like moieties can accelerate the whole growth process of CdTe NCs comparing with TGA-like or ...
Queffélec Clémence - - 2008
An efficient synthesis of the acid part of salvianolic acid E 2 is described. Compound 2 was obtained from vanillin in 10 steps and 21% overall yield. During the synthesis of 2 an unexpected 5-oxo-4b,9b-dihydroindano[1,2-b]benzofuran rac-12 was isolated. Both compounds together with the acid part of salvianolic acid D were ...
Van Bogaert I N A - - 2008
Synthesis of medium-chain sophorolipids by Candida bombicola is a challenging objective. One of the difficulties is that the obtained sophorolipids always represent a mixture of medium-chain and native de novo formed or long-chain sophorolipids. The fatty acid moiety of de novo sophorolipids is derived from the de novo synthesis of ...
Martin Connor L - - 2008
The first total synthesis of (+/-)-actinophyllic acid (1) is reported. Key steps of this synthesis include an intramolecular oxidative coupling of ketone and malonic ester enolates and an aza-Cope-Mannich rearrangement that assembled the core structure of the natural product's unique ring system. The synthesis was accomplished from di-tert-butyl malonate in ...
Levine Mindy - - 2008
A plausible origin of biomolecular homochirality is advanced, where alpha-methyl amino acids found on meteorites transfer their chirality in the synthesis of normal amino acids. This asymmetry can be amplified to nearly homochiral levels, thus providing the necessary prerequisite for life to start on this planet and elsewhere in the ...
Stauffer Christina S - - 2008
Amipurimycin, a member of the complex peptidyl nucleoside family of antibiotics, is a Streptomyces-derived potent antifungal agent. The mechanism of action of amipurimycin, however, remains undetermined. Additionally, there are no reports on the total synthesis or structure-activity relationships (SAR) of this potentially useful bioactive compound. In a study aimed at ...
Lagrille Olivier - - 2009
Amino acid N-carboxyanhydrides (NCA), convenient monomer for polypeptide synthesis, are easily prepared in high purity as the result of N-carbamoyl amino acids (CAA) nitrosation by gaseous NOx (4:1 NO + O2 mixture, or NOCl) in toluene. Removal of polar side products is then efficiently carried out during subsequent work-up and ...
Iwaoka Michio - - 2008
Selenium-containing amino acids have attracted increasing interest from view points of the importance as active centers of several selenoenzymes, the biological synthesis, the metabolism, and the use for structure determination of proteins. In this article, our recent progresses in the transformation from sulfur-containing amino acids to selenocysteine (SeCys) and selenomethionine ...
Hughes David T - - 2008
Liposarcomas constitute a rare group of tumors of mesenchymal origin that are often poorly responsive to therapy. This study characterizes a novel human liposarcoma cell line (LiSa-2) and defines the mechanism of its response to a synthetic triterpenoid. Fatty acid synthase (FAS) is a key enzyme of de-novo fatty acid ...
Sugimoto Koichi - - 2008
Sulfur(S)-starvation was previously shown to induce the degradation of an acidic lipid in chloroplasts, sulfoquinovosyl diacylglycerol (SQDG), to yield a major internal S-source in a green alga, Chlamydomonas reinhardtii. We here found that the synthesis of phosphatidylglycerol (PG), the other acidic lipid in chloroplasts, is activated to elevate its content ...
Awasthi Neeraj Praphulla - - 2008
Fatty acid amides like erucamide are mainly used for lubrication and as slip agent to decrease friction in polymer and plastic industry. Erucamide is normally synthesized by ammonolysis of triglycerides or fatty acids at 200 degrees C and at high pressure (345-690 kPa.). However using urea in place of ammonia ...
Blau Lorena - - 2008
We report the synthesis and total NMR characterization of 5-thia-1-azabicyclo-[4.2.0]oct-2-ene-2-carboxylic acid-3-[[[(4''-nitrophenoxy)carbonyl]oxy]-methyl]-8-oxo-7-[(2-thienyloxoacetyl)amino]-diphenylmethyl ester-5-dioxide (5), a new cephalosporin derivative. This compound can be used as the carrier of a wide range of drugs containing an amino group. The preparation of the intermediate product, 5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid-3-[methyl 4-(6-methoxyquinolin-8-ylamino)pentylcarbamate]-8-oxo-7-[(2-thienyloxoacetyl)amino]-diphenylmethyl ester-5-dioxide (6), as well as the ...
Cudic Mare - - 2008
Many biological interactions and functions are mediated by glycans, consequently leading to the emerging importance of carbohydrate and glycoconjugate chemistry in the design of novel drug therapeutics. Despite the challenges that carbohydrate moieties bring into the synthesis of glycopeptides and glycoproteins, considerable progress has been made during recent decades. Glycopeptides ...
Maddess Matthew L - - 2008
This chapter derives its inspiration from the challenges presented to total synthesis chemists, by a particular group of macrocyclic pipecolic acid natural products. Although there is considerable emphasis on the completed syntheses of the main characters (FK506 (1), the antascomycins (4 and 5) and rapamycin (7)), the overall complexity of ...
Khan Khalid Mohammed - - 2008
A microwave-assisted, environmentally friendly, high-yielding, time-saving synthesis of medicinally important 3-substituted isocoumarins was carried out in a single step by direct condensation of homophthalic acid with aryol and acyl chlorides under solvent-free conditions without any solid support. The synthesised isocoumarins were structurally characterised by microanalysis, 1H NMR, EI, IR and ...
Hirose Toshiyuki - - 2008
The first total synthesis of (+)-achalensolide was achieved from a commercially available d-(-)-isoascorbic acid. The known epoxide, derived from d-(-)-isoascorbic acid, was converted into the allenyne, the Rh(I)-catalyzed Pauson-Khand-type reaction of which directly provided the bicyclo[5.3.0]decane system, a core framework of the title natural product. The construction of the gamma-lactone ...
Tatai János - - 2008
Efficient preparations of thioglycoside derivatives of L-idose and L-iduronic acid are described. The method avoids the tedious chromatographic separations of furanose and pyranose anomeric mixtures, and affords the thioglycosides in a stereoselective manner. The L-idose and L-iduronic acid thioglycosides having combinations of different protecting groups proved to be efficient glycosyl ...
Blauvelt Marisa L - - 2008
The unique reactivity of 2-methyleneoxetanes and 1,5-dioxaspiro[3.2]hexanes has been exploited for the synthesis of epi-oxetin (26), an oxetane-containing beta-amino acid. While the preparation of the natural product oxetin (1) was the original goal, the unexpected diastereoselectivity of an precedented reduction provided the epi-oxetin framework. The methodology described herein should be ...
Dai Qing - - 2008
Lack of sufficient quantities of isotopically labeled materials has precluded the use of heavy atom isotope effects to investigate mechanisms of nucleotidyl transfer reactions in nucleic acids. Here we achieve regioselective opening of 2,2'-cyclouridine with [(18)O2]benzoic acid/potassium hydride, allowing an efficient "one-pot" synthesis of [2'-18O]uridine in 88% yield. Conversion to ...
Enrichi Francesco - - 2008
In this work we discuss and investigate the morphological and optical properties of luminescent silica spheres which can have interesting applications in bioimaging and biosensing. The spheres are synthesized following an acid route by the hydrolysis and condensation of tetraethylortosilicate (TEOS) and can be functionalized by incorporation of aminopropyl-triethoxysilane (APTES) ...
Kridel Steven J - - 2007
Fatty acid synthase (FASN) is the enzyme that catalyzes the de novo synthesis of fatty acids in cells. Because of the strong expression in many cancers, FASN is an attractive and tractable target for therapeutic intervention. The discovery and development of pharmacologic agents that block FASN activity highlight the promise ...
Kim Jong-Yun - - 2007
Synthesis of mesoporous silica microspheres larger than 10 microm via surfactant template approach has rarely been reported. According to the previous studies, particle morphologies were highly variable, depending on the synthesis conditions and impeller design such as impeller type, size, and agitation speed. A new robust surfactant-template synthesis strategy for ...
StepieĊ„ Marcin - - 2007
A facile synthesis of a functionalized cyclononatripyrrole derivative is described. It involves the iodine-catalyzed cyclotrimerization of ethyl 3,3-dimethyl-5,7-dihydro[1,3]dioxepino[5,6-c]pyrrole-6-carboxylate in methanol. The product obtained in this way exists solely in the crown conformation typical of cyclononatripyrroles. However, in contrast to previously reported compounds of this class, it possesses three labile methoxymethyl ...
Lim San Hua - - 2007
A comprehensive study of the hydrothermal synthesis of TiO2-derived nanostructured materials, including layered protonic trititanate (H2Ti3O7), metal-ion exchangeable titanate (Na(x)H(2-x)Ti3O7), TiO2(B) and anatase nanotubes and TiO2-anatase nanowires, was conducted. Nanoscaled tubular structures were found to be already present in the samples derived from prolonged hydrothermal process of bulk anatase TiO2 ...
Roy Bimalendu - - 2008
Simple and convergent synthesis of a tetra- and a trisaccharide portions of an antitumor compound Julibroside J(28), isolated from Albizia julibrissin, that showed significant in vitro antitumor activity against HeLa, Bel-7402 and PC-3M-1E8 cancer cell lines is reported. The tetrasaccharide has been synthesized as its p-methoxyphenyl glycoside starting from commercially ...
Traina Christopher A - - 2007
Rare earth ion-doped yttrium oxide (Y2O3) nanocrystals are nontoxic and can be prepared as upconversion materials for cellular imaging, but they do not suspend well in water. In contrast to their tendency to dissolve in acidic media, yttria (Y2O3) nanoparticles readily react with phosphonic acids to give phosphonate-bonded yttria particles. ...
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