The Enzymatic Oxidation of Reduced Diphosphopyridine Nucleotide in the Maize Root Tip by an Oxidation Product of Ascorbic Acid

1961 ◽  
Vol 14 (2) ◽  
pp. 266-274 ◽  
Author(s):  
Dan Mertz
1950 ◽  
Author(s):  
Gabriel Baldovinos de la Pena
Keyword(s):  

1956 ◽  
Vol 2 (1) ◽  
pp. 87-92 ◽  
Author(s):  
William A. Jensen ◽  
Leroy G. Kavaljian

The intracellular distribution of ascorbic acid was studied in frozen-dried root tips of Allium cepa and Vicia faba by the silver nitrate procedure. The sites of the ascorbic acid as indicated by the deposited silver appear as spherical (0.2 to 0.6 µ in diameter) cytoplasmic particles. The site appears to have small amounts of lipides and to be rich in ribonucleic acid. These particles are concluded to be submicroscopic in size and associated, in the elongating cell, with the cell surface. In the meristematic cells they appear fewer in number and are distributed throughout the cytoplasm.


1993 ◽  
Vol 125 (2) ◽  
pp. 413-429 ◽  
Author(s):  
R. M. ABEYSEKERA ◽  
M. E. McCULLY

Genome ◽  
1996 ◽  
Vol 39 (4) ◽  
pp. 697-703 ◽  
Author(s):  
Jai-Heon Lee ◽  
K. Arumuganathan ◽  
S. M. Kaeppler ◽  
C. M. Papa ◽  
H. F. Kaeppler

Accumulation of cells containing metaphase chromosomes is an important step in cytological analyses and chromosome sorting procedures. The goal of this research was to optimize treatment parameters to synchronize the cell cycle of maize root tip meristem cells. Levels of hydroxyurea, a DNA synthesis inhibitor, were assessed for their utility in accumulating cells at the G1 phase of the cell cycle. Trifluralin, amiprophos-methyl, and colchicine were used to accumulate cells containing metaphase chromosomes upon release from hydroxyurea inhibition. Optimal mitotic indices were achieved by treating seedlings with 5 mM hydroxyurea for 18 h, incubating for 1 h without chemical treatment to release the hydroxyurea block, and then treating emerging roots with 1 μM trifluralin for 4 h. The mitotic index of synchronized maize root tips was over 70%. Uniformity of synchronization depended upon selection of seeds with emerging radicles that were similar in length at the time of treatment. Suspensions of intact chromosomes were prepared by a simple slicing procedure. The chromosome preparations were found to be suitable for flow cytometric characterization and sorting. Chromosome peaks of the observed flow karyotype resembled the predicted flow karyotype calculated on the basis of maize chromosome size. Key words : flow karyotype, hydroxyurea, plant chromosome sorting, trifluralin.


Author(s):  
Sen Gao ◽  
Frank R. Fronczek ◽  
Andrew W. Maverick

A copper(II) complex, (2,2′-bipyridine-κ2 N,N′)[2-hydroxy-2-(hydroxymethyl-κO)propanedioato-κ2 O 1,O 3]copper(II), [Cu(C4H4O6)(C10H8N2)], containing the unusual anionic chelating ligand 2-(hydroxymethyl)tartronate, has been synthesized. [Cu(bpy)2(NO3)](NO3) was mixed with ascorbic acid and Dabco (1,4-diazabicyclo[2.2.2]octane) in DMF (dimethylformamide) solution in the presence of air to produce the title compound. The structure consists of square-pyramidal complexes that are joined by Cu...O contacts [2.703 (2) Å] into centrosymmetric dimers. The C4H4O6 2− ligand, which occupies three coordination sites at Cu, has previously been identified as an oxidation product of ascorbate ion.


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