Since melatonin was identified in plants decades ago, much attention has been devoted to discovering its role in plant science. There is still a great deal to learn about the functional importance of melatonin, as well as its functional mode. In this paper, we examine the role of melatonin treatment in the response of Malus hupehensis Rehd. to alkaline conditions. Stressed seedlings showed chlo...

Physiological polyamines are ubiquitous polycations with pleiotropic biochemical activities, including regulation of gene expression, cell proliferation and modulation of cell signalling. Reports that the polyamines with cytoprotective activities were induced by diverse stresses raised the hypothesis that physiological polyamines may play a role in inducing stress response. In a wide range of o...

Polyamines (PAs) are involved in various developmental processes, especially plant flowering. Their significant influences have been established; however, the exact mechanism by which PAs regulate flowering remains unclear. To explore PA metabolism flowering, gibberellic acid (GA3, 0~2400 mg L?1) and spermidine (Spd, 0~1 mM) were applied alone or combination during early stage of flower bud for...

Polyamines, such as putrescine, spermidine and spermine, have indirectly been linked with the regulation of gene expression, and their concentrations are typically increased in cancer cells. Although effects on transcription factor binding to cognate DNA targets have been demonstrated, the mechanisms of the biological action of polyamines is poorly understood. Employing uranyl photo-probing we ...

Polyamines are closely related to many aspects of cell growth. Since increased amounts of polyamines in the urine of human cancer patients were reported in 1971, polyamines have been studied from the standpoint of tumor markers. In this study, polyamines in erythrocytes, plasma and urine were determined in 42 controls and 105 patients with gynecologic malignant tumors. The changes in polyamine ...

Two cultivars contrasting in NaCl tolerance were used to investigate the possible involvement of polyamines in salt tolerant mechanisms in roots of vegetable soybean. ‘Tianfeng’, the salt tolerant cultivar exhibited overall higher contents of free, soluble conjugated and insoluble bound forms of polyamines (putrescine, spermidine and spermine) except for free spermidine over the salt sensitive ...

The balance between accumulation of stress-induced polyamines and reactive oxygen species (ROS) is arguably a critical factor in plant tolerance to salt stress. Polyamines are compounds, which accumulate in plants under salt stress and help maintain cellular ROS homeostasis. In this review we first outline the role of polyamines in mediating salt stress responses through their modulation of red...

Polyamines--putrescine, spermidine, and spermine--are ubiquitous cellular components that play an important role in cell growth and differentiation. Using A431 cells, a cell line that overexpresses the epidermal growth factor (EGF) receptor, we found that polyamines modulate EGF-mediated growth inhibition. The natural polyamine, putrescine, was the most effective, followed by diamines containin...

Polyamines are essential for optimal cell growth. The regulation of polyamine biosynthetic, but not catabolic, enzymes has been studied in detail. Because intracellular polyamine contents depend on both synthesis and catabolism, we studied the regulation of spermidine/spermine N1-acetyltransferase (N1SSAT), the first enzyme in polyamine catabolism. Steady-state RNA levels of N1SSAT increased 3-...

Centipedegrass (Eremochloa ophiuroides [Munro] Hack.) is an important warm-season turfgrass species with low turf maintenance requirements. However, our knowledge on physiological adaptation of centipedegrass to drought stress is limited. Physiological responses to drought in a gamma-ray-induced mutant 22-1 as compared with two wild type (WT) lines were analyzed for understanding of drought tol...