Barbara A. Zilinskas

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A method for the detection of ascorbate peroxidase activity in native electrophoretic gels is described. The assay is based on the ability of ascorbate peroxidase to prevent the ascorbate-dependent reduction of nitroblue tetrazolium in the presence of H2O2. The method was found to be both sensitive (detection of less than 0.01 units of ascorbate peroxidase(More)
Salt damage to plants has been attributed to a combination of several factors including mainly osmotic stress and the accumulation of toxic ions. Recent findings in our laboratory showed that phospholipid hydroperoxide glutathione peroxidase (PHGPX), an enzyme active in the cellular antioxidant system, was induced by salt in citrus cells and mainly in roots(More)
The molecular mechanism underlying the regulation of the expression of Apxl, the gene encoding cytosolic ascorbate peroxidase, as well as other antioxidant enzymes, was studied during the progression of drought stress and following recovery from drought. Increase in steady-state transcript levels of the cytosolic isozymes of ascorbate peroxidase and(More)
Mutants of the cyanobacterium Synechocystis sp. Pasteur Culture Collection (PCC) 6803 that specifically lack the extrinsic 33-kDa manganese-stabilizing polypeptide of the photosystem II oxygen-evolving complex have been constructed by two independent methods. Cartridge mutagenesis was used to insertionally inactivate the psbO gene of one mutant and(More)
The cytosolic isoform of ascorbate peroxidase was purified to homogeneity from 14-day-old pea (Pisum sativum L.) shoots. The enzyme is a homodimer with molecular weight of 57,500, composed of two subunits with molecular weight of 29,500. Spectral analysis and inhibitor studies were consistent with the presence of a heme moiety. When compared with ascorbate(More)
Previous evidence suggests that hemolysin BL, which consists of a binding component, B, and two lytic components, L1 and L2, is the enterotoxin responsible for the diarrheal form of gastroenteritis caused by food-borne strains of Bacillus cereus. To prove that hemolysin BL and the enterotoxin are the same requires large amounts of these components free of(More)
A gene encoding cytosolic ascorbate peroxidase (ApxI) from pea (Pisum sativum L.) was isolated and its nucleotide sequence determined. By homologous alignment between the ApxI cDNA (Mittler, R., and Zilinskas, B. (1991) FEBS Lett. 289, 257-259) and the genomic clone, positions of introns and exons were determined. The isolated ApxI gene was found to contain(More)
Monodehydroascorbate radicals are generated in plant cells enzymatically by the hydrogen peroxide scavenging enzyme, ascorbate peroxidase, and nonenzymatically via the univalent oxidation of ascorbate by superoxide, hydroxyl, and various organic radicals. Regeneration of ascorbate is achieved by monodehydroascorbate reductase (EC 1.6.5.4) using NAD(P)H as(More)
A cDNA encoding the chloroplastic copper/zinc-superoxide dismutase of pea (Pisum sativum L.) was isolated from a cDNA library constructed in lambda gt11 from leaf mRNA. Nucleotide sequence analysis of the 875-base-pair clone revealed that it contained the complete coding sequence of the mature superoxide dismutase isozyme subunit, along with sequence(More)
It has been proposed that the mode of action of ethylenediurea, a very effective antiozonant, is via an increase in the antioxidant enzyme superoxide dismutase (EH Lee, JH Bennett [1982] Plant Physiol 69: 1444-1449). Data presented here refute that hypothesis. No ethylenediurea-associated increases in Cu/Zn-superoxide dismutase or Mn-superoxide dismutase(More)