Inhibition of protein synthesis by cycloheximide of Solanum lycopersicon seedlings under cadmium stress conditions

The effects of cycloheximide on the changes in activity of glutamate dehydrogenase-NADH dependent (NADH-GDH) and NAD+-dependent (NAD+-GDH), and glutamine synthetase (GS) were studied during the senescence of tomato seedlings in the presence or absence of cadmium. The GDH and GS1 enzymes seemed to be synthesized at the presence of cadmium. Cycloheximide-treated leaves and roots showed an increase in the expression immunostaining intensity of mRNA band gdh and gs1, suggesting an increase in neosynthesis of enzymes and genes activation. The rate of synthesis of GDH was clearly higher than that of its degradation. Cycloheximide (CHX) delayed the protein degradation processes in the cadmium stress conditions. Cycloheximide treatments produced lower gs1 and gs2 enzyme levels than their respective controls especially in leaves. However, the enzyme activity was lower in cycloheximide treated leaves and roots than in the controls. The results are discussed with reference to the requirement for protein synthesis in the cadmium stress conditions.