8 research outputs found
THE INFLUENSE OF MONOIODACETATE ON THE THERMOTOLERANCE OF Clavibacter michiganensis ssp. sepedonicus AND Saccharomyces cerevisiae
To search the antiseptic agents capable to decontaminate the plants from pathogens the combined effect of moderate heat shock (45oC) and glycolisis inhibitor monoiodoacetate (MIA) on survival of potato pathogen Clavibacter michiganensis ssp. sepedonicus (Cms) and yeast Saccharomyces cerevisiae was studied. Under optimal temperature cultivation (26oC) MIA had no toxic effect on S. cerevisiae but decreased viability of Cms. The lethal effect of MIA significantly increased during heat treatment at 45oC. MIA in the range from 0.1 to 1 mM decreased the thermotolerance of Cms and S. cerevisiae cells in 10-10000 folds in dependence from time of treatment. A minimal concentration of MIA capable to affect the thermotolerance was 0.1 and 0.3 mM for S. cerevisiae and Cms, respectively. The effect of MIA on Cms and yeast survival during heat shock was stronger in logarithmic phase than in stationary ones
AMIODARONE INDUCES THE SYNTHESIS OF HSPS IN SACCHAROMYCES CEREVISIAE AND ARABIDOPSIS THALIANA CELLS
Many biotic and abiotic stresses cause an increase of cytosolic Ca2+ level in cells. Calcium is one of the most important second messengers, regulating many various activities in the cell and was known to affect expression of stress activated genes. Mild heat shock induces the expression of heat shock proteins (Hsps) which protect cell from drastic heat shock exposure. There are some literature data permitting to suggest that transient elevation of cytosolic Ca2+ level in plant cells is important for activation of Hsps expression. On the other hand mitochondria are known to regulate the intracellular calcium and reactive oxygen species signaling. It has been shown recently that mild heat shock induces hyperpolarization of inner mitochondrial membrane in plant and yeast cells and this event is critically important for activation of Hsps expression. To reveal the relationship between mitochondrial activity, intracellular calcium homeostasis and Hsps expression an antiarrhythmic drug amiodarone (AMD) have been used. AMD is known to cause transient increase of cytosolic Ca2+ level in Saccharomyces cerevisiae. Obtained results have showed that AMD treatment induced the synthesis of Hsp104p in S. cerevisiae cells and Hsp101p in A. thaliana cell culture. Induction of Hsp104p synthesis leads to enhanced yeast capability to survive lethal heat shock exposure. Development of S. cerevisiae thermotolerance depended significantly on the presence of Hsp104p. Elevation of Hsp104p level in the result of AMD treatment was shown to be governed by activity of Msn2p and Msn4p transcription factors. Deletion of the MSN2 and MSN4 genes abrogated the AMD ability to induce Hsp104p synthesis. Mild heat shock and AMD treatment induced the hyperpolarization of the inner mitochondrial membrane in yeast and Arabidopsis cells which accompanied by HSP synthesis and development of thermotolerance. It was suggested that increase of cytosolic Ca2+ level after AMD treatment directly or indirectly causes the activation of mitochondrial activity which leads to hyperpolarization of the inner mitochondrial membrane and production of reactive oxygen species (ROS). Modulation of cellular Ca2+ and ROS signals by mitochondria is assumed to play a prominent role in activation of Hsps expression in yeast and plant cells
Activation of Cell Death in the Sugar Cane Suspension Culture by the Exposure to High Temperature
The process of cell death in a sugar cane suspension culture after exposure to high temperature (45, 50, 55 and 60 °C) during 10 min has been studied. It has been revealed that treatment of cell culture at 50 °C did not cause an immediate cell death, but 50% of the cells were dying for the next 48 h. Exposure of cell culture to more high temperature (55 - 60 °C) caused a massive cell death occurred instantly after treatment. The development of cell death after the treatment at 50 °C was accompanied by the protoplast condensation, increased generation of reactive oxygen species and hyperpolarization of the mitochondrial inner membrane. Obtained results indicate on the active character of the cell death process, induced by the moderate heat shock in sugar cane suspension culture
Biological Effects of Potato Plants Transformation with Glucose Oxidase Gene and their Resistance to Hyperthermia
It is known that regulation of plant tolerance to adverse environmental factors is connected with short term increase of the concentration of endogenous reactive oxygen species (ROS), which are signalling molecules for the induction of protective mechanisms. Introduction and expression of heterologous gox gene, which encodes glucose oxidase enzyme in plant genome, induce constantly higher content of hydrogen peroxide in plant tissues. It is not known how the introduction of native or modified gox gene affects the plant resistance to high-temperature stress, one of the most commonly used model for the study of stress response and thermal tolerance. In this study, we investigated biological effects of transformation and evaluated the resistance to temperature stress of potato plants with altered levels of glucose oxidase expression. Transformation of potato plants by gox gene led to the more early coming out from tuber dormancy of transformed plants and slower growth rate. Transformants containing the glucose oxidase gene were more sensitive to lethal thermal shock (50 °C, 90 min) than the transformant with the empty vector (pBI) or untransformed plants (CK). Pre-heating of plants at 37 °C significantly weakened the damaging effect of lethal thermal shock. This attenuation was more significant in the non-transformed plants