فهرست مطالب taha azad

The apoptotic protease-activating factor 1 (Apaf-1) receives the death signal in the intrinsic or mitochondrial pathway of apoptosis. Upon the releasing of cytochrome c from the intermembrane space of mitochondria and binding to Apaf-1 molecules, a heptameric apoptosome complex is formed and triggers the downstream cascade of caspases. Here, for the first time we present spontaneous mutations and recombinations of the Apaf-1 gene and its neighbouring sequences. We sequence 48 colonies containing pcDNA3.1 vector with Nluc/Apaf1 and Cluc/Apaf1 obtained through the quick-change site-directed mutagenesis method, transforming to DH5-α and XL10-Gold at two temperatures, 18 and 37ºC. In 21 of these cases, we found 38 different mutations. Our data suggest that there is a direct relationship between bacterial incubation temperatures and the number of unwanted spontaneous mutations. During our experiment we found that the Apaf-1 gene is much less susceptible to spontaneous mutations when it is transformed into XL10-Gold at 18 ºC. In contrast, a large number of spontaneous mutations were found when the gene of interest transformed into DH5α at 37ºC.

Ornithine is a non-proteinogenic amino acid, which plays an essential role in the metabolism of plants. Regard to the chirality of the molecule, physiological response of the plant cells to its two enantiomers have not been widely investigated yet. In the present study, suspension-cultured tobacco cells were treated with 1 mM of D- and Lenantiomers of ornithine in normal conditions as well as under stress of 50 mM NaCl. Differential effects of L- and D-enanthiomers were observed either in normal or under salinity stress conditions. L-ornithin adversely affected the growth of tobacco cells in normal conditions and its detrimental effect was intensified by salinity. Treatment with D-ornithine however, not only did not change the growth but also alleviated it under salt stress. Physiological response of tobacco cells to D-ornithine in normal conditions was accompanied by increasing of polyamines. Under salinity stress however, D-ornithine treatment increased the activity of major antioxidant enzymes i.e., superoxide dismutase, catalase, and peroxidase and also increased proline content of the cells, all together resulted in lowering H2O2 and maintenance of cells membrane integrity. The results suggested that D-ornithine is a potent compound for activation of anti-oxidant system of plant cells and alleviation of stress condition.

Ornithine is a non-proteinogenic amino acid, which plays an essential role in the metabolism of plants. Regard to the chirality of the molecule, physiological response of the plant cells to its two enantiomers have not been widely investigated yet. In the present study, suspension-cultured tobacco cells were treated with 1 mM of D- and Lenantiomers of ornithine in normal conditions as well as under stress of 50 mM NaCl. Differential effects of L- and D-enanthiomers were observed either in normal or under salinity stress conditions. L-ornithin adversely affected the growth of tobacco cells in normal conditions and its detrimental effect was intensified by salinity. Treatment with D-ornithine however, not only did not change the growth but also alleviated it under salt stress. Physiological response of tobacco cells to D-ornithine in normal conditions was accompanied by increasing of polyamines. Under salinity stress however, D-ornithine treatment increased the activity of major antioxidant enzymes i.e., superoxide dismutase, catalase, and peroxidase and also increased proline content of the cells, all together resulted in lowering H2O2 and maintenance of cells membrane integrity. The results suggested that D-ornithine is a potent compound for activation of anti-oxidant system of plant cells and alleviation of stress condition.