We studied the effect of branched-chain polyamines on the folding transition of genome-sized DNA molecules in aqueous solution by the use of single-molecule observation with fluorescence microcopy. Detailed morphological features of polyamine/DNA complexes were characterized by atomic force microscopy (AFM). The AFM observations indicated that branched-chain polyamines tend to induce a characte...

Extreme thermophiles produce two types of unusual polyamine: long linear polyamines such as caldopentamine and caldohexamine, and branched polyamines such as quaternary ammonium compounds [e.g. tetrakis(3-aminopropyl)ammonium]. To clarify the physiological roles of long linear and branched polyamines in thermophiles, we synthesized them chemically and tested their effects on the stability of ds...

An efficient method of somatic embryogenesis using exogenous polyamines through suspension culture protocol was developed from leaf derived callus of spine gourd (Momordica dioica Roxb. ex. Willd.). Embryogenic callus was originated from cut slices of leaf explants on MS solid medium supplemented with 4.4 μM 2,4-D with addition of polyamines (putrescine, spermidine and spermine). Putrescine at ...

1. The activation of human peripheral blood lymphocytes by phytohaemagglutinin in vitro was accompanied by striking increases in the concentrations of the natural polyamines putrescine, spermidine and spermine. 2. The enhanced accumulation of polyamines could be almost totally abolished by dl-alpha-difluoromethylornithine, a newly discovered irreversible inhibitor of l-ornithine decarboxylase (...

All mammalian cells depend on polyamines for normal growth and proliferation, but the exact roles of polyamines at the molecular level remain largely unknown. The RNA-binding protein HuR modulates the stability and translation of many target mRNAs. Here, we show that in rat intestinal epithelial cells (IECs), polyamines enhanced HuR association with the 3'-untranslated region of the c-Myc mRNA ...

Phytohormones (PHs) play crucial role in regulation of various physiological and biochemical processes that govern plant growth yield under optimal stress conditions. The interaction these PHs is for survival stressful environments as they trigger signaling pathways. Hormonal cross initiate a cascade reactions which finely tune the architecture help to grow suboptimal Recently, studies have hig...

Plants can be regenerated from various explants/tissues via de novo shoot meristem formation. Most of these regeneration pathways are indirect and involve callus Besides plant hormones, the role polyamines (PAs) has been implicated in processes. Interestingly, lateral root primordia (LRPs) Arabidopsis directly converted to meristems by exogenous cytokinin application. In this system, no formati...

The levels of free, perchloric acid-soluble conjugated and perchloric acid-insoluble bound polyamines were determined in pericarp and seeds of `Muscat Bailey A' grapes (Vitis labrusca L. Vitis vinifera L.) during development and ripening. In both, the pericarp and seeds, putrescine was the predominant polyamine in the three fractions, and the bound polyamine level was the highest of the fractio...

Diamines and polyamines are ubiquitous components of living cells, and apparently are involved in numerous cellular and physiological processes. Certain "uncommon" polyamines have limited distribution in nature and have been associated primarily with organisms adapted to extreme environments, although the precise function of these polyamines in such organisms is unknown. This article summarizes...