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The photosynthetic wild type and the spontaneous non-photosynthetic WZSL mutant of the unicellular flagellate Euglena gracilis were grown to investigate the influence of photoheterotrophic and heterotrophic conditions on α-tocopherol (vitamin E) content. HPLC analysis demonstrated a marked enhancement (almost 100%) of tocopherol content in the light in both(More)
Cell death via apoptosis induced by tumor necrosis factor-alpha (TNF-alpha) plays an important role in many physiological and pathological conditions. The signal transduction pathway activated by this cytokine is known to be regulated by several intracellular messengers. In particular, in many systems nitric oxide (NO) has been shown to protect cells from(More)
Apoptosis triggered by death receptors proceeds after defined signal-transduction pathways. Whether signaling at the receptor level is regulated by intracellular messengers is still unknown. We have investigated the role of two messengers, ceramide and nitric oxide (NO), on the apoptotic pathway activated in human monocytic U937 cells by tumor necrosis(More)
The kinetic properties of a 300-fold purified cardiac AMP deaminase were studied and compared with those of the corresponding enzyme from skeletal muscle. The heart enzyme is activated by ATP and less efficiently by ADP, and is inhibited by Pi, phosphocreatine and GTP. ATP, even at micromolar concentrations, is able to abolish the effects of the inhibitors.(More)
Activation of acid and neutral sphingomyelinases, and the ensuing generation of ceramide, contributes to the biological effects of tumour necrosis factor-alpha (TNF-alpha), one of which is apoptosis. While the mechanisms of activation of sphingomyelinases by the cytokine are being unravelled, less is known about regulation of their activity. Nitric oxide(More)
L-Glutamate decarboxylase (GAD) activity of Clostridium perfringens (ATCC 8009) cells grown in various culture conditions was investigated. Remarkable variations of GAD level occur during the growth cycle in thioglycollate broth. These changes are affected by the pH of the culture medium. Addition of alkali to the culture media results in decrease of cell(More)
The enzyme endothelial Nitric Oxide Synthase (eNOS) is involved in key physiological and pathological processes, including cell motility and apoptosis. It is widely believed that at the cell surface eNOS is localized in caveolae, where caveolin-1 negatively regulates its activity, however, there are still uncertainties on its intracellular distribution.(More)
Activation of endothelial nitric-oxide synthase (eNOS) has been shown to occur through various pathways involving increases in the cytosolic Ca(2+) concentration, activation of the phosphatidylinositol-3' kinase/Akt pathway, as well as regulation by other kinases and by protein-protein interactions. We have recently reported that eNOS, expressed in an(More)
Somatic mutations of the TSH receptor (TSHR) gene have been identified as the major cause of toxic thyroid adenoma. Recently, point mutations of the same gene have also been described in some differentiated thyroid carcinomas. The aim of the present study was to investigate the presence TSHR gene mutations in a series of thyroid specimens obtained from 22(More)