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The regulation of cytokinin oxidase activity in callus tissues of Phaseolus vulgaris L. cv Great Northern has been examined using an assay based on the oxidation of N(6)-(Delta(2)-isopentenyl)adenine-8-(14)C (i(6) Ade-8-(14)C) to adenine. Solutions of exogenous cytokinins applied directly to the surface of the callus tissues induced relatively rapid(More)
Sequence analysis of ribulosebisphosphate carboxylase/oxygenase (rubisco) activase cDNA and genomic clones isolated from spinach and Arabidopsis thaliana indicates that the two polypeptides of rubisco activase arise from alternative splicing of a common pre-mRNA. In spinach, two 5' splice sites are used in processing a single 137-nucleotide intron near the(More)
Ribulose 1,5-bisphosphate carboxylase/oxygenase (rubisco) activase protein was purified from spinach leaves by ammonium sulfate precipitation and ion exchange fast protein liquid chromatography. This resulted in 48-fold purification with 70% recovery of activity and yielded up to 18 milligrams of rubisco activase protein from 100 grams of leaves. Based on(More)
Ascorbate peroxidase (AP) is a key enzyme that scavenges potentially harmful H2O2 and thus prevents oxidative damage in plants, especially in N2-fixing legume root nodules. The present study demonstrates that the nodule endodermis of alfalfa (Medicago sativa) root nodules contains elevated levels of AP protein, as well as the corresponding mRNA transcript(More)
The effects of metal ions on cytokinin oxidase activity extracted from callus tissues of Phaseolus vulgaris L. cv Great Northern have been examined using an assay based on the oxidation of N(6)-(Delta(2)-isopentenyl)-adenine-2,8-(3)H (i(6) Ade) to adenine (Ade). The addition of cupric ions to reaction mixtures containing imidazole buffer markedly enhanced(More)
Ascorbate peroxidase is a widespread plant enzyme that catalyzes the removal of potentially harmful H2O2. This enzyme is particularly important in legume root nodules due to their high potential for generating activated forms of oxygen. A cDNA clone of soybean nodule ascorbate peroxidase was used to construct an expression system in Escherichia coli. The(More)
A common feature of development in most vertebrate models is the early segregation of the germ line from the soma. For example, in Xenopus and zebrafish embryos primordial germ cells (PGCs) are specified by germ plasm that is inherited from the egg; in mice, Blimp1 expression in the epiblast mediates the commitment of cells to the germ line. How these(More)
Ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) activase activity was obtained from a partially purified extract of Escherichia coli transformed with a 1.6-kilobase spinach (Spinacia oleracea L.) cDNA clone. This activity was ATP-dependent. Catalysis of rubisco activation by spinach and cloned rubisco activase was accompanied by the same extent of(More)
Cytokinin oxidase activity from Phaseolus vulgaris cv Great Northern callus cultures exhibited affinity for the lectin concanavalin A. Over 80% of the activity extracted from the callus tissue bound to a concanavalin A-Sepharose 4B column. The bound activity was eluted from the column by the addition of methylmannose to the eluting buffer. On the basis of(More)
Cells in the pluripotent ground state can give rise to somatic cells and germ cells, and the acquisition of pluripotency is dependent on the expression of Nanog. Pluripotency is conserved in the primitive ectoderm of embryos from mammals and urodele amphibians, and here we report the isolation of a Nanog ortholog from axolotls (axNanog). axNanog does not(More)