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Karel Grohmann - One of the best experts on this subject based on the ideXlab platform.
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phenols in citrus peel byproducts concentrations of hydroxycinnamates and polymethoxylated flavones in citrus peel molasses
Journal of Agricultural and Food Chemistry, 2001Co-Authors: John A Manthey, Karel GrohmannAbstract:In addition to the main flavanone glycosides (i.e., hesperidin and naringin) in citrus peel, polymethoxylated flavones and numerous hydroxycinnamates also occur and are major phenolic constituents of the molasses byproduct generated from fruit processing. Although a small number of the hydroxycinnamates in citrus occur as amides, most occur as esters and are susceptible to alkaline hydrolysis. This susceptibility to alkaline hydrolysis was used in measuring the concentrations of hydroxycinnamates in citrus peel molasses. The highest concentrations of hydroxycinnamates occurred in molasses of orange [C. sinensis (L.) Osbeck] and tangerine (C. reticulata Blanco.) compared to grapefruit (C. paradisi Macf.) and lemon [C. limon (L.) Burm.]. Concentrations of two phenolic glucosides, phlorin (phloroglucinol-beta-O-glucoside) and Coniferin (coniferyl alcohol-4-beta-O-glucoside), were also measured. Measurements of the polymethoxylated flavones in molasses from several tangerine and orange varieties showed that these compounds occurred in the highest amounts in Dancy tangerine, whereas samples from two other tangerine molasses contained significantly lower levels, similar to those in the molasses samples from late- and early/mid-season oranges.
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phenols in citrus peel byproducts concentrations of hydroxycinnamates and polymethoxylated flavones in citrus peel molasses
Journal of Agricultural and Food Chemistry, 2001Co-Authors: John A Manthey, Karel GrohmannAbstract:In addition to the main flavanone glycosides (i.e., hesperidin and naringin) in citrus peel, polymethoxylated flavones and numerous hydroxycinnamates also occur and are major phenolic constituents of the molasses byproduct generated from fruit processing. Although a small number of the hydroxycinnamates in citrus occur as amides, most occur as esters and are susceptible to alkaline hydrolysis. This susceptibility to alkaline hydrolysis was used in measuring the concentrations of hydroxycinnamates in citrus peel molasses. The highest concentrations of hydroxycinnamates occurred in molasses of orange [C. sinensis (L.) Osbeck] and tangerine (C. reticulata Blanco.) compared to grapefruit (C. paradisi Macf.) and lemon [C. limon (L.) Burm.]. Concentrations of two phenolic glucosides, phlorin (phloroglucinol-β-O-glucoside) and Coniferin (coniferyl alcohol-4-β-O-glucoside), were also measured. Measurements of the polymethoxylated flavones in molasses from several tangerine and orange varieties showed that these c...
John A Manthey - One of the best experts on this subject based on the ideXlab platform.
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phenols in citrus peel byproducts concentrations of hydroxycinnamates and polymethoxylated flavones in citrus peel molasses
Journal of Agricultural and Food Chemistry, 2001Co-Authors: John A Manthey, Karel GrohmannAbstract:In addition to the main flavanone glycosides (i.e., hesperidin and naringin) in citrus peel, polymethoxylated flavones and numerous hydroxycinnamates also occur and are major phenolic constituents of the molasses byproduct generated from fruit processing. Although a small number of the hydroxycinnamates in citrus occur as amides, most occur as esters and are susceptible to alkaline hydrolysis. This susceptibility to alkaline hydrolysis was used in measuring the concentrations of hydroxycinnamates in citrus peel molasses. The highest concentrations of hydroxycinnamates occurred in molasses of orange [C. sinensis (L.) Osbeck] and tangerine (C. reticulata Blanco.) compared to grapefruit (C. paradisi Macf.) and lemon [C. limon (L.) Burm.]. Concentrations of two phenolic glucosides, phlorin (phloroglucinol-beta-O-glucoside) and Coniferin (coniferyl alcohol-4-beta-O-glucoside), were also measured. Measurements of the polymethoxylated flavones in molasses from several tangerine and orange varieties showed that these compounds occurred in the highest amounts in Dancy tangerine, whereas samples from two other tangerine molasses contained significantly lower levels, similar to those in the molasses samples from late- and early/mid-season oranges.
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phenols in citrus peel byproducts concentrations of hydroxycinnamates and polymethoxylated flavones in citrus peel molasses
Journal of Agricultural and Food Chemistry, 2001Co-Authors: John A Manthey, Karel GrohmannAbstract:In addition to the main flavanone glycosides (i.e., hesperidin and naringin) in citrus peel, polymethoxylated flavones and numerous hydroxycinnamates also occur and are major phenolic constituents of the molasses byproduct generated from fruit processing. Although a small number of the hydroxycinnamates in citrus occur as amides, most occur as esters and are susceptible to alkaline hydrolysis. This susceptibility to alkaline hydrolysis was used in measuring the concentrations of hydroxycinnamates in citrus peel molasses. The highest concentrations of hydroxycinnamates occurred in molasses of orange [C. sinensis (L.) Osbeck] and tangerine (C. reticulata Blanco.) compared to grapefruit (C. paradisi Macf.) and lemon [C. limon (L.) Burm.]. Concentrations of two phenolic glucosides, phlorin (phloroglucinol-β-O-glucoside) and Coniferin (coniferyl alcohol-4-β-O-glucoside), were also measured. Measurements of the polymethoxylated flavones in molasses from several tangerine and orange varieties showed that these c...
John E. Carlson - One of the best experts on this subject based on the ideXlab platform.
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Polymorphic β–glucosidase gene in Pinus taeda and Pinus contorta involved in lignification
2015Co-Authors: Anushree Sengupta, Song Liu, John E. CarlsonAbstract:Abstract: Coniferin beta-glucosidase (CBG) is involved in the extracellular steps of the lignin biosynthetic pathway. CBG releases the lignin precursor, coniferyl alcohol, from its glucoside form, Coniferin, prior to polymerization in the cell wall. Our hypothesis is that Coniferin serves as an intracellular transport form of coniferyl alcohol from the cytosol to the cell wall. Thus, release of its aglycone in the cell wall is likely be an essential step in lignin biosynthesis in vivo. We previously published the cDNA sequence and enzymology of CBG from lodgepole pine Dharmawardhana et al. (1995). We now present the complete chromosomal copies of CBG genes identified in lodgepole and loblolly pines. Two copies of the gene were found in lodgepole pine, and four forms of the gene in loblolly pine. Our analysis suggests that DNA polymorphisms are also present among CBG genes from different trees. Lignin is an important component of wood, but is detrimental to several industrial processes like pulp and paper making or biofuels. It is hypothesized that the monomers of lignin such as coniferyl alcohol ar
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A beta-glucosidase from lodgepole pine xylem specific for the lignin precursor Coniferin.
Plant physiology, 1995Co-Authors: D. P. Dharmawardhana, Brian E. Ellis, John E. CarlsonAbstract:Coniferin, the glucoside of the monolignol coniferyl alcohol, accumulates to high levels in gymnosperms during spring-cambial reactivation. A cinnamyl alcohol glucoside/[beta]-glucosidase system is thought to play a key role in lignification by releasing the monolignol aglycones. Investigation of such an enzyme system in the xylem of Pinus contorta var latifolia Engelm. revealed two major [beta]-glucosidases. One efficiently hydrolyzed the native substrate, Coniferin, and the other was more active against synthetic glucosides. The Coniferin [beta]-glucosidase was purified to apparent homogeneity using anion exchange, hydrophobic interaction, and size-exclusion chromatography. The apparent native molecular weight was estimated to be 60,000. A dominant 28-kD protein and a minor 24-kD protein were detected in the purified preparation following sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Immunological evidence from polyclonal antibodies directed against the synthetic N-terminal peptide of the 24-kD protein suggested that the native protein is a dimer of 28-kD subunit size. The N-terminal sequence showed that Coniferin [beta]-glucosidase has high homology to known plant [beta]-glucosidases. Coniferin, syringin, and a synthetic Coniferin analog were preferred substrates for the Coniferin [beta]-glucosidase. In situ localization using the chromogenic Coniferin analog showed the exclusive presence of [beta]-glucosidase activity in the differentiating xylem, similar to peroxidase activity.
Ronald R. Sederoff - One of the best experts on this subject based on the ideXlab platform.
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4-Coumarate-coenzyme-a ligase from loblolly-pine xylem-Isolation, characterization, and complementary-DNA cloning
Plant physiology, 1995Co-Authors: Kui Shin Voo, Ross W. Whetten, David M. O'malley, Ronald R. SederoffAbstract:4-Coumarate:CoA ligase (4CL, EC 6.2.1.12) was purified from differentiating xylem of loblolly pine (Pinus taeda L.). The pine enzyme had an apparent molecular mass of 64 kD and was similar in size and kinetic properties to 4CL isolated from Norway spruce. The pine enzyme used 4-coumaric acid, caffeic acid, ferulic acid, and cinnamic acid as substrates but had no detectable activity using sinapic acid. 4CL was inhibited by naringenin and Coniferin, products of phenylpropanoid metabolism. Although the lignin composition in compression wood is higher in p-hydroxyphenyl units than lignin from normal wood, there was no evidence for a different form of 4CL enzyme in differentiating xylem that was forming compression wood. cDNA clones for 4CL were obtained from a xylem expression library. The cDNA sequences matched pine xylem 4CL protein sequences and showed 60 to 66% DNA sequence identity with 4CL sequences from herbaceous angiosperms. There were two classes of cDNA obtained from pine xylem, and the genetic analysis showed that they were products of a single gene.
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purification characterization and cloning of cinnamyl alcohol dehydrogenase in loblolly pine pinus taeda l
Plant Physiology, 1992Co-Authors: D M Omalley, Stephanie Porte, Ronald R. SederoffAbstract:Cinnamyl alcohol dehydrogenase (CAD, EC 1.1.1. 195) has been purified to homogeneity from differentiating xylem tissue and developing seeds of loblolly pine (Pinus taeda L.). The enzyme is a dimer with a native molecular weight of 82,000 and a subunit molecular weight of 44,000, and is the only form of CAD involved in lignification in differentiating xylem. High levels of loblolly pine CAD enzyme were found in nonlignifying seed tissue. Characterization of the enzyme from both seeds and xylem demonstrated that the enzyme is the same in both tissues. The enzyme has a high affinity for coniferaldehyde (Km = 1.7 micromolar) compared with sinapaldehyde (Km in excess of 100 micromolar). Kinetic data strongly suggest that Coniferin is a noncompetitive inhibitor of CAD enzyme activity. Protein sequences were obtained for the N-terminus (28 amino acids) and for two other peptides. Degenerate oligonucleotide primers based on the protein sequences were used to amplify by polymerase chain reaction a 1050 base pair DNA fragment from xylem cDNA. Nucleotide sequence from the cloned DNA fragment coded for the N-terminal protein sequence and an internal peptide of CAD. The N-terminal protein sequence has little similarity with the λCAD4 clone isolated from bean (MH Walter, J Grima-Pettenati, C Grand, AM Boudet, CJ Lamb [1988] Proc Natl Acad Sci USA 86:5546-5550), which has homology with malic enzyme.
Pauline M Doran - One of the best experts on this subject based on the ideXlab platform.
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production of podophyllotoxin using cross species coculture of linum flavum hairy roots and podophyllum hexandrum cell suspensions
Biotechnology Progress, 2003Co-Authors: Hanwei Lin, Kian H Kwok, Pauline M DoranAbstract:Novel cross-species coculture systems using Linum flavum hairy roots and Podophyllum hexandrum cell suspensions were applied for in vitro production of podophyllotoxin. The hairy roots and suspensions were cocultured in Linsmaier and Skoog medium in dual shake flasks and dual bioreactors. In separate experiments, Coniferin feeding was shown to be an effective strategy for increasing the accumulation of podophyllotoxin in P. hexandrum suspensions. Because roots of L. flavum are a natural source of Coniferin, hairy roots of this species were used in coculture with P. hexandrum to provide an in situ supply of Coniferin. Compared with P. hexandrum suspensions cultured alone in shake flasks or bioreactors, podophyllotoxin concentrations in cocultured P. hexandrum cells were increased by 240% and 72% in dual shake flask and dual bioreactor systems, respectively. The availability and stability of Coniferin in the medium are the most likely factors limiting podophyllotoxin synthesis in coculture. Intensification of the coculture process is required to further improve total podophyllotoxin accumulation on a volumetric basis.