The nuclear content of conjugated polyamines increased during rat liver regeneration. Conjugated polyamines isolated from the acid-precipitable fraction of nuclei required peptide bond hydrolysis for release of the parent compounds. The most striking change occurred in conjugated putrescine which fluctuated in a biphasic manner; maximal nuclear levels 12-fold and 25-fold above those of sham-ope...

Several lines of evidence have suggested, but not proved, that polyamines are associated with DNA in intact cells. In an attempt to investigate the roles of polyamines in gene-associated functions, we examined the effects of polyamine depletion on the spontaneous mutation rate in a rat basophilic leukemia cell line. The frequency of 6-thioguanine-resistant mutant cells increased by approximatel...

The cellular accumulations of polyamines and ribonucleic acid (RNA) were compared in the polyauxotrophic mutants of Escherichia coli strain 15 TAU and E. coli K-12 RC(re1) met(-) leu(-). Putrescine, spermidine, and their monoacetyl derivatives were the main polyamines in both strains, when grown in glucose-mineral medium. No significant degradation of either (14)C-putrescine or (14)C-spermidine...

Fungi, as well as the rest of living organisms must deal with environmental challenges such as stressful stimuli. Fungi are excellent models to study the general mechanisms of the response to stress, because of their simple, but conserved, signal-transduction and metabolic pathways that are often equivalent to those present in other eukaryotic systems. A factor that has been demonstrated to be ...

In a number of biological systems undergoing accelerated growth there is a rapid accumulation of polyamines, particularly spermidine, in parallel with RNA. One of the first events in such systems is a rapid increase in the activity of ornithine decarboxylase to as much as 100 times control values (Williams-Ashman, 1972). However, the increase in the amount of polyamines is much less marked, usu...

We studied absorption, distribution, metabolism, and excretion of polyamines (putrescine, spermidine, and spermine) in the gastrointestinal tract using (15)N-labeled polyamines as tracers and ionspray ionization mass spectrometry (IS-MS). The relatively simple protocol using rats bearing solid tumors provided useful information. Three (15)N-labeled polyamines that were simultaneously administer...

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...

The polyamines putrescine, spermidine, and spermine are multivalent cations that bind to anionic cell constituents such as nucleic acids. Their distribution between free and bound states within the cell is not known. Such knowledge would be important in relation to the negative control of polyamine synthesis. We report a tracer experiment in which [14C]ornithine was added to logarithmically gro...

The polyamines are abundant biogenic cations implicated in many biological processes. Despite a plethora of evidence on polyamine-induced DNA conformational changes, no thorough study of their effects on the activities of sequence-specific DNA binding proteins has been performed. We describe the in vitro effects of polyamines on the activities of purified, representative DNA-binding proteins, a...

While decades of research have focused on snake venom proteins, far less attention has been paid to small organic venom constituents. Using mostly pooled samples, we surveyed 31 venoms (six elapid, six viperid, and 19 crotalid) for spermine, spermidine, putrescine, and cadaverine. Most venoms contained all four polyamines, although some in essentially trace quantities. Spermine is a potentially...