Carotenogenesis in maize and rice.
Item
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Title
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Carotenogenesis in maize and rice.
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Identifier
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AAI9997108
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identifier
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9997108
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Creator
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Matthews, Paul David.
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Contributor
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Adviser: E. T. Wurtzel
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Date
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2001
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Language
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English
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Publisher
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City University of New York.
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Subject
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Biology, Genetics | Biology, Molecular
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Abstract
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Carotenoids have diverse roles at all levels of biological organization. These plant pigments serve as light-harvesters, photoprotectors, antioxidants, colorants, animal attractants, and as metabolic precursors to odorants and abscisic acid. In animals they are dietary precursors to retinoic acid, retinal, and retinol. Because of these health-related roles in human and animals, they impact on both natural and human ecology. Presented is the development and improvement of tools for the comparative understanding and metabolic engineering of carotenogenesis in representative cereal crops, maize (Zea mays L) and rice (Oryzae sativa L). Improvements to an Erwinia uredovora heterologous genetic functional complementation system in Escherichia coli include (1) ranking and choice of bacterial strains (TOP10F' ranked best) for stability and degree of carotenoid accumulation and (2) recommendations for color complementation screening of cDNA libraries and (3) increased (up to 10.8 times) accumulation of zeaxanthin and lycopene by metabolic engineering of carotenogensis with genetic modulation of the isoprenoid precursor pool by overexpression of deoxyxylulose phosphate synthase (DOXP). I also report functional analyses of the concerted action of maize phytoene desaturase (PDS) and zeta-carotene desaturase (MS) by combined HPLC separation and PDA analyses of geometric isomers of carotenoids accumulating in E. coli. Maize PDS and ZDS mediated a poly-Z-desaturation pathway to 7,9,7,9'-Z-lycopene (poly-cis-lycopene or prolycopene). The existence of a poly-Z-desaturation pathway for maize PDS and ZDS is discussed in relation to two divergent interpretations. For each interpretation implications for genetic manipulation and further study of maize carotenogenesis are given. Finally, I report isolation and characterization of a partial, rice cDNA and corresponding gene of phytoene synthase ( Psy). I also report the chromosomal map location of rice Psy. I analyzed protein and nucleic acid primary sequence for chloroplast transit peptide prediction, protein domain homology, phenetic phylogenetic relationships, gene copy number and possible syntenic relationships among maize and rice. The relation of the novel rice Psy gene to the genetic locus, maize Yellow1 (Y1), is also considered.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
