The naturally occurring polyamines putrescine, spermidine, and spermine are involved in signal transduction. This has been demonstrated by using inhibitors for polyamine biosynthesis (such as alpha-difluoromethylornithine) or adding polyamines to cultured cells. Different polyamines, preferentially activated protein kinases (tyrosine kinases and MAP kinases), stimulated the expression of nuclea...

The incorporation of l-[(14)C]ornithine and [(14)C]putrescine into putrescine, spermidine, and spermine in type 5 adenovirus-infected KB cells was identical to that in uninfected control cells early in infection, but incorporation into putrescine stopped after 8 to 12 h and the rate of incorporation into spermidine was reduced between 12 and 20 h after infection. The amount of polyamines found ...

Polyamines are polycations that interact with negatively charged molecules such as DNA, RNA and proteins. They play multiple roles in cell growth, survival and proliferation. Changes in polyamine levels have been associated with aging and diseases. Their levels decline continuously with age and polyamine (spermidine or high-polyamine diet) supplementation increases life span in model organisms....

Intestinal mitochondria have a phospholipase D (PLD) activity which was stimulated by polyamines and monoamines resulting in the formation of phosphatidic acid (PA) from endogenous phospholipids. When stimulated by polyamines, mitochondrial PLD utilized endogenous phosphatidylethanolamine (PE) as substrate whereas stimulated by monoamines, both PE and phosphatidylcholine (PC) were hydrolysed. S...

The levels of free, conjugated and bound polyamines (PA) were analyzed during the cell cycle of the synchronized unicellular green alga Scenedesmus obliquus. The polyamines putrescine (PUT) and spermidine (SPD) in their free and conjugated forms accumulated per cell to a maximum in the cell cycle at about the 16th hour after onset of illumination. The polyamines bound to macromolecules and memb...

Polyamines, such as spermidine (Spd) spermine (Spm) and their direct precursor, the diamine putrescine (Put) are vital essential aliphatic amines which also present in plants. Although ethylene polyamines involved fruit ripening, genes coding them must take part other biosynthetic pathways. In play an important role development of salt stress tolerance, responses for biotic abiotic stresses. Ex...

Polyamines play a fundamental role in the functioning of all cells. Their regulatory plant development, their function under stress conditions, and metabolism have been well documented as regards both synthesis catabolism an increasing number species. However, majority these studies concentrate on levels most abundant polyamines, sometimes providing data enzyme activity or gene expression durin...

Ubiquitous in nature, polyamines are a group of aliphatic amines, cationic at neutral pH, that are essential for cell growth and viability. Because of their positive charge, polyamines are able to bind by electrostatic linkages to many cellular macromolecules, including DNA, RNA, and proteins (Kusano et al. 2008). Polyamines are involved in the regulation of a diverse range of vital cellular pr...

Molecules, depending on their nature, can cross the lipid bilayer of the cell membrane by simple diffusion or by a protein carrier-mediated process. Camermediated transport occurs by facilitated diffusion through a channel or pore, or by the specific interaction with a 'mobile' transporter protein. The transport of polyamines into and out of the cell has been found to compliment de nova biosynt...