Syntheses of Kinetin-analogues. II

Okumura, F. Shigeo; Kotani, Yachio; Ariga, Tomoyuki; Masumura, Mitsuo; Kuraishi, Susumu

doi:10.1246/bcsj.32.883

Cited by 21 publications

(4 citation statements)

References 3 publications

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“…Studies on the effect of aromatic substituents on the activity of b6Ade [20] provide support for this hypothesis. The activity of orthosubstituted derivatives of b6Ade depends on the nature of the substituent, ortho-OMe or CF3 Table 1 Torsion angles in degrees for the side chains of several cytokinins Molecule ¢~1 ¢/2 ~3 f6Ade 73 110 7 i6Ade 63 87 2 b6Ade 72 102 6 2MeSi6Ade 216 103 1 b6Ado 145 78 -6 f6Ado 57 106 12 substitution greatly diminishes cytokinin activity, while ortho-Cl substitution has only a small effect.…”

Section: Resultsmentioning

confidence: 81%

A stereochemical model for cytokinin activity

1989

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Section: Resultsmentioning

confidence: 81%

A stereochemical model for cytokinin activity

1989

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“…C, 61.2; H, 5.1; N, 27.4%); TLC, single spot: HPLC: purity > 99%; m.p. 272–273°C (248–249°C according to Okomura et al 1959). 1 H‐NMR (DMSO‐d 6 , 300 MHz): days 3.70 (s, 3H, OCH3), 4.68 (bs, 2H, CH 2 Ph), 6.78 (dt, 1H, Ph), 6.91 (s, 1H, Ph), 6.93 (d, 1H, Ph), 7.20 (t, 1H, Ph), 8.13 (s, 1H, purine H (2)), 8.19 (s, 1H, purine H (8)), 12.92 (s, 1H, NH).…”

Section: Methodsmentioning

confidence: 99%

Identification of new aromatic cytokinins in Arabidopsis thaliana and Populus × canadensis leaves by LC‐(+)ESI‐MS and capillary liquid chromatography/frit–fast atom bombardment mass spectrometry

Tarkowská

Doležal

Tarkowski

et al. 2003

Physiologia Plantarum

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A search for naturally occurring aromatic cytokinins (ARCKs) in Arabidopsis thaliana plants and Populus x canadensis leaves led to the discovery of four new plant hormone substances: 6-(2-methoxybenzylamino)purine (ortho-methoxytopolin, MeoT), 6-(3-methoxybenzylamino)purine (meta-methoxytopolin, MemT) (Fig. 1) and their 9-beta-D-ribofuranosyl derivatives. These substances were identified by liquid chromatography electrospray ionization mass spectrometry [LC (+)ESI-MS] and capillary-liquid chromatography/frit-fast atom bombardment-mass spectrometry [CapLC/frit-FAB-MS] after pre-column derivatization. The chemical structures were subsequently confirmed by chemical synthesis. Because of lack of heavy labelled internal standards, the endogenous levels of methoxytopolins in A. thaliana plants, Populus x canadensis leaves and samples derived from cultures of Agrobacterium tumefaciens strain GV3101 were determined by enzyme-linked immunosorbent assay (ELISA) of HPLC-fractionated extracts. While the levels of MeoT, MemT and their ribosides in A. thaliana shoots and Populus x canadensis leaves were relatively low (approximately 0.25-10 pmol g-1 FW for MeoT and MemT, respectively), the A. tumefaciens strain produced up to 600 times more of the newly identified substances. Cytokinin activity of methoxytopolines was demonstrated in three bioassays testing their ability to stimulate tobacco callus growth, to delay chlorophyll degradation in excised wheat leaves, and to induce betacyanin synthesis in Amaranthus caudatus var. atropurpurea cotyledons. Notably, their anti-senescing activity in the wheat leaf assay exceeded that of BAP and Z by almost 200%. Methoxytopolins are proposed to be new members of the biologically active aromatic cytokinin family, which might have specific physiological functions.

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“…The exploration of cytokinins (CKs) dates back to 1955 when Miller et al [1] identified kinetin as the first cytokinin, recognizing its cell-division-promoting properties. Subsequently, in 1959, Okumura et al [2] synthesized a spectrum of kinetin analogues and BA (benzyladenine) derivatives. Their activities remained elusive for nearly three decades until Kaminek et al [3] unveiled the significant biological effects of topolins, in 1987.…”

Section: Introductionmentioning

confidence: 99%

New Understanding of Meta-Topolin Riboside Metabolism in Micropropagated Woody Plants

Grira,

Prinsen,

Werbrouck

2024

Plants

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Topolin cytokinins have emerged as valuable tools in micropropagation. This study investigates the metabolism of meta-topolin riboside (mTR) in three distinct tree species: Handroanthus guayacan and Tabebuia rosea (Bignoniaceae), and Tectona grandis (Lamiaceae). Employing labeled N15 mTR, we unraveled the complex mechanisms underlying cytokinin homeostasis, identifying N9-glucosylation as the principal deactivation pathway. Our findings demonstrate a capacity in T. rosea and H. guayacan to reposition the hydroxyl group on the cytokinin molecule, a previously unexplored metabolic pathway. Notably, this study reveals remarkable interfamilial and interspecies differences in mTR metabolism, challenging established perspectives on the role of callus tissue in cytokinin storage. These insights not only illuminate the metabolic intricacies of mTR, a cytokinin with interesting applications in plant tissue culture, but also enhances our understanding of cytokinin dynamics in plant systems, thereby enriching the scientific discourse on plant physiology and cytokinin biology.

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Syntheses of Kinetin-analogues. II

Cited by 21 publications

References 3 publications

A stereochemical model for cytokinin activity

A stereochemical model for cytokinin activity

Identification of new aromatic cytokinins in Arabidopsis thaliana and Populus × canadensis leaves by LC‐(+)ESI‐MS and capillary liquid chromatography/frit–fast atom bombardment mass spectrometry

New Understanding of Meta-Topolin Riboside Metabolism in Micropropagated Woody Plants

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