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J.E. Fox

Bio: J.E. Fox is an academic researcher from University of Kansas. The author has contributed to research in topics: Metabolite & Cytokinin. The author has an hindex of 2, co-authored 2 publications receiving 142 citations.

Papers
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Journal ArticleDOI
TL;DR: Two types of cytokinin binding sites exist on higher plant ribosomes and one of these, a high affinity site, binds cytokinins at low concentrations, is saturated at one cytokinIn molecule per ribosome, is specific for substances with cytokin in activity.

100 citations

Journal ArticleDOI
TL;DR: This metabolite has now been tentatively identified as 6-benzylamino-7-glucofuranosylpurine on the basis of its U. V. and mass spectra and associated data, and is not degraded by α- or β-glucosidases, perhaps because of its unusual structure.

44 citations


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Book
01 Jan 1989
TL;DR: The dominant objective of Biochemistry and Physiology of Plant Hormones is to summarize, in a reasonably balanced and comprehensive way, the current state of fundamental knowledge regarding the major kinds of hormones and the phytochrome pigment system.
Abstract: Biochemistry and Physiology oj Plant Hormones is intended primarily as a textbook or major reference for a one-term intermediate-level or advanced course dealing with hormonal regulation of growth and development of seed plants for students majoring in biology, botany, and applied botany fields such as agronomy, forestry, and horticulture. Additionally, it should be useful to others who wish to become familiar with the topic in relation to their principal student or professional interests in related fields. It is assumed that readers will have a background in fundamental biology, plant physiology, and biochemistry. The dominant objective of Biochemistry and Physiology oj Plant Hor mones is to summarize, in a reasonably balanced and comprehensive way, the current state of our fundamental knowledge regarding the major kinds of hormones and the phytochrome pigment system. Written primarily for students rather than researchers, the book is purposely brief. Biochemical aspects have been given priority intentionally, somewhat at the expense of physiological considerations. There are extensive citations of the literature-both old and recent-but, it is hoped, not so much documentation as to make the book difficult to read. The specific choices of publications to cite and illustrations to present were made for different reasons, often to illustrate historical develop ment, sometimes to illustrate ideas that later proved invalid, occasionally to exemplify conflicting hypotheses, and most often to illustrate the current state of our knowledge about hormonal phenomena."

334 citations

Journal ArticleDOI
01 Sep 1973-Planta
TL;DR: The principal metabolites formed from zeatin by the roots of intact Z. mays seedlings were adenosine-5′-phosphate, zeat in riboside, adenine,Adenosine and an unknown compound termed Y.mays which was isolated and identified as 9-glucosylzeatin.
Abstract: [3H]Zeatin was supplied through the transpiration stream to radish (Raphanus sativus L.) seedlings with roots excised. Formation of dihydrozeatin was not detected but numerous other metabolites were formed, including adenine, adenosine, AMP, zeatin riboside and zeatin riboside-5′-monophosphate. However, in labelled seedlings which had been left in water for 15 h, an unknown compound (raphanatin) was the dominant metabolite and accounted for about 25% of the total radioactivity extracted. A procedure for the isolation of this metabolite was devised and yielded 70 μg from 1600 seedlings. Raphanatin was characterized by mass and ultraviolet spectra and has been identified as 7-glucosylzeatin. It is an active and very stable metabolite which was located mainly in the cotyledon laminae and may be a storage form of the hormone. In contrast, labelled nucleotides, the other major metabolites of zeatin, were largely confined to the hypocotyls and petioles. Zeatin riboside-5′-monophosphate was the dominant metabolite in hypocotyls of de-rooted seedlings supplied with zeatin for 0.5–2 h. The majority of the radioactivity in the xylem sap was due to zeatin, but about 10% was present as zeatin riboside; nucleotides accounted for less than 10% of the radioactivity and labelled raphanatin was not detected.

308 citations

Journal ArticleDOI
TL;DR: This review attempts to put into context what is known about 9-alkyl-BAs and compares their metabolism in regard to the practical use of cytokinins in agriculture and biotechnology.
Abstract: After the discovery of kinetin (Miller et al. 1956, J. Am. Chem. Soc. 78: 1345–1350) there was a flurry of syntheses that led to the finding of 6-benzylaminopurine (BA), an active and easily obtainable cytokinin. Much research into cytokinin physiology was subsequently done with this substance. Further, the isolation and unequivocal identification of natural BA and the high biological activity of its meta-hydroxylated analogues stimulated the search for other natural aromatic cytokinins. Screening was accomplished by ELISA of HPLC fractions using antisera against ortho- and meta-hydroxybenzyladenosine. Subsequent isolation and decisive identification by mass spectrometry led to discovery of a broad spectrum of endogenous plant growth substances structurally similar to a highly active compound, meta-topolin (6-[3-hydroxybenzyl-amino]purine), and to its less active analogue, ortho-topolin (6-[2-hydroxybenzyl-amino]purine). The structures of such aromatic cytokinins suggest considerably different biosynthetic pathways from that of zeatin and related isoprenoid cytokinins. From a physiological viewpoint, aromatic cytokinin metabolism can be classified under four main headings analogous to isoprenoid cytokinins: interconversion, hydroxylation, conjugation, and oxidative degradation. This review attempts to put into context what is known about 9-alkyl-BAs and compares their metabolism in regard to the practical use of cytokinins in agriculture and biotechnology. The recently discovered unusual specificity of additionally C2,N9-disubstituted aromatic cytokinins toward cell cycle kinases, suggests that these cytokinin-derived growth regulators may selectively inhibit certain steps of the cell cycle. The functional overlap of the aromatic cytokinins with those of their isoprenoid counterparts and cytokinin inhibitors, in relation to growth and developmental processes in plants, has yet to be determined.

225 citations

Journal ArticleDOI
TL;DR: Although indications are presented that the promotion of chloroplast development by cytokinins is closely connected with a stimulation of the gene expression program for plastogenesis, other sites of hormone action cannot be excluded and are discussed in the last part of the review.

139 citations