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744 results on '"Olsen, C. E."'

10. The terpene synthase gene family in Tripterygium wilfordii harbors a labdane-type diterpene synthase among the monoterpene synthase TPS-b subfamily

Author

Hansen, N. L., Heskes, A. M., Hamberger, B., Olsen, C. E., Hallström, Björn M., Andersen-Ranberg, J., Hansen, N. L., Heskes, A. M., Hamberger, B., Olsen, C. E., Hallström, Björn M., and Andersen-Ranberg, J.

Abstract

Tripterygium wilfordii (Celastraceae) is a medicinal plant with anti-inflammatory and immunosuppressive properties. Identification of a vast array of unusual sesquiterpenoids, diterpenoids and triterpenoids in T. wilfordii has spurred investigations of their pharmacological properties. The tri-epoxide lactone triptolide was the first of many diterpenoids identified, attracting interest due to the spectrum of bioactivities. To probe the genetic underpinning of diterpenoid diversity, an expansion of the class II diterpene synthase (diTPS) family was recently identified in a leaf transcriptome. Following detection of triptolide and simple diterpene scaffolds in the root, we sequenced and mined the root transcriptome. This allowed identification of the root-specific complement of TPSs and an expansion in the class I diTPS family. Functional characterization of the class II diTPSs established their activities in the formation of four C-20 diphosphate intermediates, precursors of both generalized and specialized metabolism and a novel scaffold for Celastraceae. Functional pairs of the class I and II enzymes resulted in formation of three scaffolds, accounting for some of the terpenoid diversity found in T. wilfordii. The absence of activity-forming abietane-type diterpenes encouraged further testing of TPSs outside the canonical class I diTPS family. TwTPS27, close relative of mono-TPSs, was found to couple with TwTPS9, converting normal-copalyl diphosphate to miltiradiene. The phylogenetic distance to established diTPSs indicates neo-functionalization of TwTPS27 into a diTPS, a function not previously observed in the TPS-b subfamily. This example of evolutionary convergence expands the functionality of TPSs in the TPS-b family and may contribute miltiradiene to the diterpenoids of T. wilfordii., QC 20170609

Published
2017
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11. Muon Diffusion in Noble Metals

Author

Schillaci, M. E., Bokema, C., Heffner, R. H., Hutson, R. L., Leon, M., Olsen, C. E., Dodds, S. A., MacLaughlin, D. E., Richards, P. M., Jena, P., editor, and Satterthwaite, C. B., editor

Published
1983
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20. Applications of Pulsed Neutron Powder Diffraction to Actinide Elements

Author

Lawson, A. C., primary, Cort, B., additional, Olsen, C. E., additional, Richardson, J. W., additional, Mueller, M. H., additional, Lander, G. H., additional, Goldstone, J. A., additional, Williams, A., additional, Kwei, G. H., additional, von Dreele, R. B., additional, Faber, J., additional, and Hitterman, R. L., additional

Published
1988
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24. Anomalous surface impedance in reentrant ferromagnetic superconductors.

Author

Huang, C. Y., Olsen, C. E., Kozlowski, G., Matsumoto, H., Umezawa, H., Mancini, F., Maple, M. B., Hamaker, H. C., Torikachvili, M. S., Whitehead, J. P., and Wang, F. E.

Subjects
*FERROMAGNETISM, *SUPERCONDUCTORS, *ERBIUM, *RHODIUM, *BORON
Abstract

Focuses on a study which examined ferromagnetisim in a ferromagnetic superconductor arising from the competition between the Meissner current shielding effect and the fluctuations of the localized magnetic moments. Background on the compound erbium rhodium[sub4] boron[sub4]; Surface impedance of nonmagnetic superconductors; Values for the inverse of the characteristic length or solid curve.

Published
1985
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28. CYP79F1 and CYP79F2 have distinct functions in the biosynthesis of aliphatic glucosinolates in Arabidopsis

Author

Chen, S., Glawischnig, E., Jorgensen, K., Naur, P., Jorgensen, B., Olsen, C-E., Hansen, C. H., Rasmussen, H. B., Pickett, J. A., and Halkier, B. A.

Subjects
Plant Sciences, food and beverages
Abstract

Cytochromes P450 of the CYP79 family catalyze the conversion of amino acids to oximes in the biosynthesis of glucosinolates, a group of natural plant products known to be involved in plant defense and as a source of flavor compounds, cancer-preventing agents and bioherbicides. We report a detailed biochemical analysis of the substrate specificity and kinetics of CYP79F1 and CYP79F2, two cytochromes P450 involved in the biosynthesis of aliphatic glucosinolates in Arabidopsis thaliana . Using recombinant CYP79F1 and CYP79F2 expressed in Escherichia coli and Saccharomyces cerevisiae, respectively, we show that CYP79F1 metabolizes mono- to hexahomomethionine, resulting in both short- and long-chain aliphatic glucosinolates. In contrast, CYP79F2 exclusively metabolizes long-chain elongated penta- and hexahomomethionines. CYP79F1 and CYP79F2 are spatially and developmentally regulated, with different gene expression patterns. CYP79F2 is highly expressed in hypocotyl and roots, whereas CYP79F1 is strongly expressed in cotyledons, rosette leaves, stems, and siliques. A transposon-tagged CYP79F1 knockout mutant completely lacks short-chain aliphatic glucosinolates, but has an increased level of long-chain aliphatic glucosinolates, especially in leaves and seeds. The level of long-chain aliphatic glucosinolates in a transposon-tagged CYP79F2 knockout mutant is substantially reduced, whereas the level of short-chain aliphatic glucosinolates is not affected. Biochemical characterization of CYP79F1 and CYP79F2, and gene expression analysis, combined with glucosinolate profiling of knockout mutants demonstrate the functional role of these enzymes. This provides valuable insights into the metabolic network leading to the biosynthesis of aliphatic glucosinolates, and into metabolic engineering of altered aliphatic glucosinolate profiles to improve nutritional value and pest resistance.

Published
2003

29. Leishmanicidal, antiplasmodial and cytotoxic activity of indole alkaloids from Corynanthe pachyceras

Author

Staerk, D, Lemmich, E, Christensen, J, Kharazmi, A, Olsen, C E, and Jaroszewski, J W

Subjects
complex mixtures
Abstract

Five indole alkaloids, corynantheidine, corynantheine, dihydrocorynantheine, alpha-yohimbine and corynanthine were isolated from bark of Corynanthe pachyceras K. Schum. (Rubiaceae). The structures were established by spectroscopic methods, including previously unreported assignment of all 1H-NMR resonances by COSY and NOESY experiments. These and related alkaloids showed pronounced activity against Leishmania major promastigotes (IC50 at the micromolar level) but no significant in vitro antiplasmodial activity (against chloroquine-sensitive Plasmodium falciparum). Cytotoxicity assessed with drug sensitive KB-3-1 and multidrug-resistant KB-V1 cell lines was low; the alkaloids are apparently not substrates for the P-glycoprotein (P-170) efflux pump.

Published
2000

31. Acetoxy drug:characterization and mass spectrometry of the acetylated protein product

Author

Kohli, E., Gaspari, M., Raj, H. G., Parmar, V. S., Sharma, S. K., Greef, J. v. d., Kumari, R., Gupta, G., Seema, Khurana, P., Tyagi, Y. K., Watterson, A. C., Olsen, C. E., Kohli, E., Gaspari, M., Raj, H. G., Parmar, V. S., Sharma, S. K., Greef, J. v. d., Kumari, R., Gupta, G., Seema, Khurana, P., Tyagi, Y. K., Watterson, A. C., and Olsen, C. E.

Published
2004

35. O-Glycosylated Cell Wall Proteins Are Essential in Root Hair Growth

Author

Velasquez, S. M., primary, Ricardi, M. M., additional, Dorosz, J. G., additional, Fernandez, P. V., additional, Nadra, A. D., additional, Pol-Fachin, L., additional, Egelund, J., additional, Gille, S., additional, Harholt, J., additional, Ciancia, M., additional, Verli, H., additional, Pauly, M., additional, Bacic, A., additional, Olsen, C. E., additional, Ulvskov, P., additional, Petersen, B. L., additional, Somerville, C., additional, Iusem, N. D., additional, and Estevez, J. M., additional

Published
2011
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36. Highly efficient diastereoselective biocatalytic acylation of a diastereotopic furanose diol and synthesis of key intermediates for amino derivatized bicyclonucleosides

Author

Prasad, A. K., Roy, S., Kumar, R., Kalra, N., Wengel, J., Olsen, C. E., Cholli, A. L., Samuelson, L. A., Kumar, J., Watterson, A. C., Gross, R. A., Parmar, V. S., Prasad, A. K., Roy, S., Kumar, R., Kalra, N., Wengel, J., Olsen, C. E., Cholli, A. L., Samuelson, L. A., Kumar, J., Watterson, A. C., Gross, R. A., and Parmar, V. S.

Published
2003

37. Mechanism of biochemical action of substituted 4-methylbenzopyran-2-ones. Part 10: Identification of inhibitors for the liver microsomal acetoxycoumarin: Protein transacetylase

Author

Raj, H. G., Singh, I., Kohli, E., Kumari, G., Gupta, G., Tyagi, Y. K., Kumar, A., Prasad, A. K., Kaushik, N. K., Olsen, C. E., Watterson, A. C., Parmar, V. S., Raj, H. G., Singh, I., Kohli, E., Kumari, G., Gupta, G., Tyagi, Y. K., Kumar, A., Prasad, A. K., Kaushik, N. K., Olsen, C. E., Watterson, A. C., and Parmar, V. S.

Published
2003

41. Synthetic, biolcatalytic acetylation andantituberculosis activity evaluation studies on (+/-)-4-alkyl-3,4-dihydro-3-omega-hydroxyalkyl-2H-1,3-benzoxazines

Author

Shakil, N. A., Dhawan, A., Sharma, N. K., Kumar, V., Kumar, S., Bose, M., Raj, H. G., Olsen, C. E., Cholli, A. L., Samuelson, L. A., Kumar, J., Watterson, A. C, Parmar, V. S., Prasad, A. K., Shakil, N. A., Dhawan, A., Sharma, N. K., Kumar, V., Kumar, S., Bose, M., Raj, H. G., Olsen, C. E., Cholli, A. L., Samuelson, L. A., Kumar, J., Watterson, A. C, Parmar, V. S., and Prasad, A. K.

Published
2003

45. Synthesis, characterization and in Vitro anti-invasive activity screening of polyphenolic and heterocyclic compounds

Author

Parmar, V. S., Sharma, N. K., Husain, M., Watterson, A. C., Kumar, J., Samuelson, L. A., Cholli, A. L., Prasad, A. K., Kumar, A., Malhotra, S., Kumar, N., Jha, A., Singh, A., Singh, I., Himanshu, ., Shakil, N. A., Trikha, S., Mukherjee, S., Sharma, S. K., Singh, S. K., Jha, H. N., Olsen, C. E., Stove, C. P., Bracke, M. E., Mareel, M. M., Parmar, V. S., Sharma, N. K., Husain, M., Watterson, A. C., Kumar, J., Samuelson, L. A., Cholli, A. L., Prasad, A. K., Kumar, A., Malhotra, S., Kumar, N., Jha, A., Singh, A., Singh, I., Himanshu, ., Shakil, N. A., Trikha, S., Mukherjee, S., Sharma, S. K., Singh, S. K., Jha, H. N., Olsen, C. E., Stove, C. P., Bracke, M. E., and Mareel, M. M.

Published
2003

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