scholarly journals Influence of cyclophosphamide on respiration and membrane permeability of plant cells

2014 ◽  
Vol 49 (4) ◽  
pp. 357-361 ◽  
Author(s):  
Maria Podbielkowska ◽  
Alicja Zobel ◽  
Maria Wałęza
Keyword(s):  
Membrane Permeability ◽  
Cell Membranes ◽  
Alkylating Agents ◽  
Plant Cells ◽  
Cellular Respiration ◽  
Cell Respiration ◽  
Experimental Conditions ◽  
Specific Influence

A specific influence of cyclophosphamide, an oncostatic drug of the group of alkylating agents, has been demonstrated on cellular respiration and the permeability of cell membranes. The tested drug under the experimental conditions inhibites cell respiration by about 20-30 per cent as compared with the control. The permeability of the plasmalemma and tonoplast de-creased markedly under the action of cyclophosphamide.

scholarly journals REGULATORY MECHANISMS OF CELLULAR RESPIRATION

1948 ◽  
Vol 32 (2) ◽  
pp. 179-190 ◽  
Author(s):  
E. S. Guzman Barron ◽  
Leonard Nelson ◽  
Maria Isabel Ardao
Keyword(s):  
Sodium Arsenite ◽  
Alkylating Agents ◽  
Small Concentration ◽  
Sulfhydryl Groups ◽  
Regulatory Mechanisms ◽  
Cellular Respiration ◽  
Cell Respiration ◽  
Sulfhydryl Reagents ◽  
Protein Moiety ◽  
Sea Urchin Sperm

Oxidizing agents of sulfhydryl groups such as iodosobenzoate, alkylating agents such as iodoacetamide, and mercaptide-forming agents such as cadmium chloride, mercuric chloride, p-chloromercuribenzoate, sodium arsenite, and p-carboxyphenylarsine oxide, added in small concentrations to a suspension of sea urchin sperm produced an increase in respiration. When the concentration was increased there was an inhibition. These effects are explained by postulating the presence in the cells of two kinds of sulfhydryl groups: soluble sulfhydryl groups, which regulate cellular respiration, and fixed sulfhydryl groups, present in the protein moiety of enzymes. Small concentrations of sulfhydryl reagents combine only with the first, thus producing an increase in respiration; when the concentration is increased, the fixed sulfhydryl groups are also attacked and inhibition of respiration is the consequence. Other inhibitors of cell respiration, such as cyanide and urethanes, which do not combine with —SH groups, did not stimulate respiration in small concentration.

scholarly journals Thermodynamics of irreversible plant cell growth

2011 ◽  
Vol 75 (3) ◽  
pp. 183-190 ◽  
Author(s):  
Mariusz Pietruszka ◽  
Sylwia Lewicka ◽  
Krystyna Pazurkiewicz-Kocot
Keyword(s):  
Cell Wall ◽  
Cell Growth ◽  
Water Absorption ◽  
Abiotic Factors ◽  
Plant Cells ◽  
Wall Stress ◽  
Growth Equation ◽  
Experimental Conditions ◽  
Linear Solution ◽  
Non Linear

The time-irreversible cell enlargement of plant cells at a constant temperature results from two independent physical processes, e.g. water absorption and cell wall yielding. In such a model cell growth starts with reduction in wall stress because of irreversible extension of the wall. The water absorption and physical expansion are spontaneous consequences of this initial modification of the cell wall (the juvenile cell vacuolate, takes up water and expands). In this model the irreversible aspect of growth arises from the extension of the cell wall. Such theory expressed quantitatively by time-dependent growth equation was elaborated by Lockhart in the 60's.The growth equation omit however a very important factor, namely the environmental temperature at which the plant cells grow. In this paper we put forward a simple phenomenological model which introduces into the growth equation the notion of temperature. Moreover, we introduce into the modified growth equation the possible influence of external growth stimulator or inhibitor (phytohormones or abiotic factors). In the presence of such external perturbations two possible theoretical solutions have been found: the linear reaction to the application of growth hormones/abiotic factors and the non-linear one. Both solutions reflect and predict two different experimental conditions, respectively (growth at constant or increasing concentration of stimulator/inhibitor). The non-linear solution reflects a common situation interesting from an environmental pollution point of view e.g. the influence of increasing (with time) concentration of toxins on plant growth. Having obtained temperature modified growth equations we can draw further qualitative and, especially, quantitative conclusions about the mechanical properties of the cell wall itself. This also concerns a new and interesting result obtained in our model: We have calculated the magnitude of the cell wall yielding coefficient (T) [m<sup>3</sup> J<sup>-1</sup>•s<sup>-1</sup>] in function of temperature which has acquired reasonable numerical value throughout.

Genetic defects in sterol synthesis, absorption, and degradation into bile acids

2011 ◽  
pp. 1673-1676
Author(s):  
Stefano Romeo
Keyword(s):  
Membrane Permeability ◽  
Bile Acids ◽  
Steroid Hormones ◽  
Cell Membranes ◽  
De Novo ◽  
Cholesterol Metabolism ◽  
The Body ◽  
Sterol Synthesis ◽  
Genetic Defects ◽  
And Function

Cholesterol is the most abundant steroid in animals. Not only is it a vital constituent of cell membranes, where it establishes proper membrane permeability and fluidity, but it is also the immediate metabolic precursor of all known steroid hormones and bile acids. Synthesized de novo in cells or absorbed from the diet, cholesterol circulates in the body in association with lipoproteins and is ultimately degraded into bile acids by the liver. Every perturbation of the numerous enzymes involved in cholesterol metabolism leads to impairment in the development and function of the gastrointestinal, cardiovascular, skeletal, and nervous systems.

Methods to quantify primary plant cell wall mechanics

2019 ◽  
Vol 70 (14) ◽  
pp. 3615-3648 ◽  
Author(s):  
Amir J Bidhendi ◽  
Anja Geitmann
Keyword(s):  
Cell Wall ◽  
Plant Cell ◽  
Plant Cell Wall ◽  
Polymer Network ◽  
Plant Cells ◽  
Tensile Tests ◽  
Mechanical Modeling ◽  
Experimental Conditions ◽  
Testing Techniques ◽  
Cell Wall Mechanics

Abstract The primary plant cell wall is a dynamically regulated composite material of multiple biopolymers that forms a scaffold enclosing the plant cells. The mechanochemical make-up of this polymer network regulates growth, morphogenesis, and stability at the cell and tissue scales. To understand the dynamics of cell wall mechanics, and how it correlates with cellular activities, several experimental frameworks have been deployed in recent years to quantify the mechanical properties of plant cells and tissues. Here we critically review the application of biomechanical tool sets pertinent to plant cell mechanics and outline some of their findings, relevance, and limitations. We also discuss methods that are less explored but hold great potential for the field, including multiscale in silico mechanical modeling that will enable a unified understanding of the mechanical behavior across the scales. Our overview reveals significant differences between the results of different mechanical testing techniques on plant material. Specifically, indentation techniques seem to consistently report lower values compared with tensile tests. Such differences may in part be due to inherent differences among the technical approaches and consequently the wall properties that they measure, and partly due to differences between experimental conditions.

scholarly journals Hybrid erythrocytes for membrane studies in sickle cell disease

Blood ◽  
1976 ◽  
Vol 47 (1) ◽  
pp. 121-131 ◽  
Author(s):  
MR Clark ◽  
SB Shohet
Keyword(s):  
Sickle Cell Disease ◽  
Membrane Permeability ◽  
Sickle Cell ◽  
Cell Membranes ◽  
Red Cell ◽  
Cell Disease ◽  
Characteristic Appearance ◽  
Sickle Hemoglobin ◽  
Red Cell Membranes ◽  
Surrounding Membrane

Abstract A hybrid erythrocyte model for membrane studies in sickle cell disease has been developed. The model consists of normal red cell membranes containing hemoglobin S and sickle cell membranes containing hemoglobin A. In hybrids, complete hemoglobin exchange has been achieved together with restoration of low membrane permeability to potassium. Normal membranes containing HbS sickle upon deoxygenation and assume the characteristic appearance of irreversibly sickled cells (ISC) after prolonged anoxia. It is suggested that the hybrid model will be useful in defining further the process of ISC formation and in studying the influence of sickle hemoglobin upon the function of the surrounding membrane.

Horseradish peroxidase as a cytochemical marker for altered cell membrane permeability in cultured myocytes after oxidative stress

1990 ◽  
Vol 48 (3) ◽  
pp. 930-931
Author(s):  
M. Ashraf ◽  
K. Aida ◽  
T. Oguro
Keyword(s):  
Oxidative Stress ◽  
Cell Membrane ◽  
Horseradish Peroxidase ◽  
Membrane Permeability ◽  
Light And Electron Microscopy ◽  
Staining Technique ◽  
Ruthenium Red ◽  
Cell Membrane Permeability ◽  
Experimental Conditions ◽  
Selective Staining

The development of a selective staining technique is important for the study of cell membrane permeability altered under different experimental conditions. This is particularly useful if the same technique or procedure is used for both light and electron microscopy examination. In this study, the effect of oxidative stress in the cultured myocytes using lanthanum (La+++), ruthenium red (RR) and horseradish peroxidase (HRP) as cytochemical markers for leaky myocytes was studied. Myocytes from adult rat hearts were isolated and cultured in modified MEM (Sigma Chemical Co.) at 37°C. Myocytes were exposed to 300 μM H2O2 for 15, 30 and 60 minutes. The cells were then rinsed, incubated in 1% HRP, 5 mM La+++ or 0.3. RR, and were fixed in 2.5% buffered glutaraldehyde for 1 hour. The HRP-treated cells were incubated in diaminobenzidine as described.After treatment with H2O2 for 15 minutes, all myocytes remained rod-shaped, and their number was decreased to 80% after 60 minutes. The staining of cells with La+++ could not be visualized under the light microscope even in the round cells, and with RR, only heavily damaged cells were distinguishable from normal cells. HRP staining yielded excellent results.

DICLOFOP-METHYL AND DICLOFOP UPTAKE IN OAT (Avena sativa L.) PROTOPLASTS

1987 ◽  
Vol 67 (1) ◽  
pp. 215-223 ◽  
Author(s):  
SUSAN A. TRITTER ◽  
F. B. HOLL ◽  
BARRY G. TODD
Keyword(s):  
Membrane Permeability ◽  
Avena Sativa ◽  
Constant Level ◽  
Experimental Conditions ◽  
Phytotoxic Activity ◽  
Time Period ◽  
Significant Difference ◽  
Herbicide Concentration

An isolated oat (Avena sativa L.) protoplast system was used to investigate the uptake of the herbicide diclofop-methyl. Membrane permeability was not adversely affected by the herbicide levels and experimental conditions reported in this study. Neither diclofop-methyl nor diclofop adversely affected membrane permeability of the protoplasts at herbicide concentrations up to 50 μM and 100 μM, respectively. Diclofop-methyl was rapidly taken up by oat protoplasts to a constant level which did not change significantly with incubation times up to 1 h. Forty percent of the added 14C-diclofop-methyl was taken up within 5 s, while diclofop uptake was only 4% over the same time period. Diclofop-methyl uptake was linear with herbicide concentration in the uptake solution up to 50 μM. There was no significant difference between diclofop-methyl uptake by burst or intact protoplast preparations. Rapid diclofop-methyl uptake by oat protoplasts is apparently not a carrier-mediated process. Diclofop was taken up at very low rates under similar experimental conditions. These differences may reflect differences in the phytotoxic activity of the two chemical forms.Key words: Oat, protoplasts, diclofop-methyl uptake

scholarly journals Boron Induces Hyperpolarization of Sunflower Root Cell Membranes and Increases Membrane Permeability to K+

1990 ◽  
Vol 93 (2) ◽  
pp. 566-571 ◽  
Author(s):  
Mary K. Schon ◽  
Anton Novacky ◽  
Dale G. Blevins
Keyword(s):  
Membrane Permeability ◽  
Cell Membranes ◽  
Root Cell

scholarly journals In Vitro and In Vivo Activation of Mitochondrial Membrane Permeability Transition Pore Using Triiodothyronine

2016 ◽  
pp. 321-331
Author(s):  
R. ENDLICHER ◽  
Z. DRAHOTA ◽  
Z. ČERVINKOVÁ
Keyword(s):  
Membrane Permeability ◽  
Mitochondrial Membrane ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Mitochondrial Membrane Permeability ◽  
Experimental Conditions ◽  
Membrane Permeability Transition ◽  
Swelling Rate

Using a novel method for evaluating mitochondrial swelling (Drahota et al. 2012a) we studied the effect of calcium (Ca2+), phosphate (Pi), and triiodothyronine (T3) on the opening of mitochondrial membrane permeability transition pore and how they interact in the activation of swelling process. We found that 0.1 mM Pi, 50 µM Ca2+ and 25 µM T3 when added separately increase the swelling rate to about 10 % of maximal values when all three factors are applied simultaneously. Our findings document that under experimental conditions in which Ca2+ and Pi are used as activating factors, the addition of T3 doubled the rate of swelling. T3 has also an activating effect on mitochondrial membrane potential. The T3 activating effect was also found after in vivo application of T3. Our data thus demonstrate that T3 has an important role in opening the mitochondrial membrane permeability pore and activates the function of the two key physiological swelling inducers, calcium and phosphate ions.

HEAT-HARDENING OF PLANT CELLS UNDER NATURAL AND EXPERIMENTAL CONDITIONS

1967 ◽  
pp. 152-160 ◽  
Author(s):  
N.L. FELDMAN ◽  
V.Y. ALEXANDROV ◽  
I.G. ZAVADSKAYA ◽  
I.M. KISLYUK ◽  
A.G. LOMAGIN ◽  
...  
Keyword(s):  
Plant Cells ◽  
Experimental Conditions ◽  
Heat Hardening
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