scholarly journals Effect of indole-3-acetic acid on pea root growth, peroxidase profiles and hydroxyl radical formation

2007 ◽  
Vol 59 (4) ◽  
pp. 319-326 ◽  
Author(s):  
Biljana Kukavica ◽  
Aleksandra Mitrovic ◽  
M. Mojovic ◽  
Sonja Veljovic-Jovanovic
Keyword(s):  
Cell Wall ◽  
Hydroxyl Radical ◽  
Root Elongation ◽  
Radical Formation ◽  
Isolated Roots ◽  
Hydroponically Grown ◽  
Indole 3 Acetic Acid ◽  
Roots In Vitro ◽  
Root Cell Wall

Changes in growth, peroxidase profiles, and hydroxyl radical formation were examined in IAA (0.5-10 mg/l) treated pea plants grown hydroponically and in isolated roots in liquid in vitro culture. IAA inhibited root elongation, both in hydroponically grown pea plants and in isolated roots in vitro. A remarkable increase in the number of POD iso?forms was noticed in isolated roots grown in vitro, compared to the roots from plants grown hydroponically. IAA induced both disappearance of several root POD isoforms and hydroxyl radical formation in the root and the root cell wall.

scholarly journals Intracellular Copper Does Not Catalyze the Formation of Oxidative DNA Damage in Escherichia coli

2006 ◽  
Vol 189 (5) ◽  
pp. 1616-1626 ◽  
Author(s):  
Lee Macomber ◽  
Christopher Rensing ◽  
James A. Imlay
Keyword(s):  
Escherichia Coli ◽  
Dna Damage ◽  
Hydroxyl Radical ◽  
Oxidative Dna Damage ◽  
Copper Toxicity ◽  
Radical Formation ◽  
Pcr Analysis ◽  
Intracellular Copper

ABSTRACT Because copper catalyzes the conversion of H2O2 to hydroxyl radicals in vitro, it has been proposed that oxidative DNA damage may be an important component of copper toxicity. Elimination of the copper export genes, copA, cueO, and cusCFBA, rendered Escherichia coli sensitive to growth inhibition by copper and provided forcing circumstances in which this hypothesis could be tested. When the cells were grown in medium supplemented with copper, the intracellular copper content increased 20-fold. However, the copper-loaded mutants were actually less sensitive to killing by H2O2 than cells grown without copper supplementation. The kinetics of cell death showed that excessive intracellular copper eliminated iron-mediated oxidative killing without contributing a copper-mediated component. Measurements of mutagenesis and quantitative PCR analysis confirmed that copper decreased the rate at which H2O2 damaged DNA. Electron paramagnetic resonance (EPR) spin trapping showed that the copper-dependent H2O2 resistance was not caused by inhibition of the Fenton reaction, for copper-supplemented cells exhibited substantial hydroxyl radical formation. However, copper EPR spectroscopy suggested that the majority of H2O2-oxidizable copper is located in the periplasm; therefore, most of the copper-mediated hydroxyl radical formation occurs in this compartment and away from the DNA. Indeed, while E. coli responds to H2O2 stress by inducing iron sequestration proteins, H2O2-stressed cells do not induce proteins that control copper levels. These observations do not explain how copper suppresses iron-mediated damage. However, it is clear that copper does not catalyze significant oxidative DNA damage in vivo; therefore, copper toxicity must occur by a different mechanism.

scholarly journals Generation of Hydroxyl Radical in Isolated Pea Root Cell Wall, and the Role of Cell Wall-Bound Peroxidase, Mn-SOD and Phenolics in Their Production

2008 ◽  
Vol 50 (2) ◽  
pp. 304-317 ◽  
Author(s):  
Biljana Kukavica ◽  
Miloš Mojović ◽  
Željko Vucčinić ◽  
Vuk Maksimović ◽  
Umeo Takahama ◽  
...  
Keyword(s):  
Cell Wall ◽  
Hydroxyl Radical ◽  
Root Cell ◽  
Pea Root ◽  
Root Cell Wall

In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

1978 ◽  
Vol 36 (2) ◽  
pp. 434-435
Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland
Keyword(s):  
Cell Wall ◽  
Self Assembly ◽  
Plant Cell Wall ◽  
Higher Plants ◽  
Three Dimensional ◽  
Cytochemical Study ◽  
Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

In vitro assembly of 2-D crystals from partially purified EA1 protein secreted by Bacillus anthracis strain Delta Sterne-1

1994 ◽  
Vol 52 ◽  
pp. 276-277
Author(s):  
Mary Beth Downs ◽  
Wilson Ribot ◽  
Joseph W. Farchaus
Keyword(s):  
Cell Wall ◽  
Molecular Sieves ◽  
Cell Envelope ◽  
Single Species ◽  
Supporting Cell ◽  
Surface Layers ◽  
Rabbit Igg ◽  
In Vitro Assembly ◽  
Covalently Linked

Many bacteria possess surface layers (S-layers) that consist of a two-dimensional protein lattice external to the cell envelope. These S-layer arrays are usually composed of a single species of protein or glycoprotein and are not covalently linked to the underlying cell wall. When removed from the cell, S-layer proteins often reassemble into a lattice identical to that found on the cell, even without supporting cell wall fragments. S-layers exist at the interface between the cell and its environment and probably serve as molecular sieves that exclude destructive macromolecules while allowing passage of small nutrients and secreted proteins. Some S-layers are refractory to ingestion by macrophages and, generally, bacteria are more virulent when S-layers are present.When grown in rich medium under aerobic conditions, B. anthracis strain Delta Sterne-1 secretes large amounts of a proteinaceous extractable antigen 1 (EA1) into the growth medium. Immunocytochemistry with rabbit polyclonal anti-EAl antibody made against the secreted protein and gold-conjugated goat anti-rabbit IgG showed that EAI was localized at the cell surface (fig 1), which suggests its role as an S-layer protein.

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