The polyamines putrescine, spermidine and spermine were analyzed in chick embryos during the first 2 days of development. A rapid increase in the activity of ornithine decarboxylase (ODC), the initial and rate-limiting enzyme in polyamine synthesis, was observed immediately after onset of incubation. Peak activities were found at 15 and 23 h of incubation. The first peak coincides with gastrula...

Biotechnology of microalgae represents a very attractive alternative as a source of energy and substances of high value when compared with plant cultivation. Cell walls of green microalgae have an extraordinary chemical and mechanical resistance and may impede some steps in the biotechnological/industrial exploitation of algae. The aim of the present contribution was to check the presence of po...

Polyamines are small cations with unique combinations of charge and length that give them many putative interactions in cells. Polyamines are essential since they are involved in replication, transcription, translation, and stabilization of macro-molecular complexes. However, polyamine synthesis competes with cellular methylation for S-adenosylmethionine, the methyl donor. Also, polyamine degra...

The effects of polyamines on the synthesis of various final sigma subunits of RNA polymerase were studied using Western blot analysis. Synthesis of final sigma(28) was stimulated 4.0-fold and that of final sigma(38) was stimulated 2.3-fold by polyamines, whereas synthesis of other final sigma subunits was not influenced by polyamines. Stimulation of final sigma(28) synthesis was due to an incre...

PURPOSE To determine whether polyamines are present in corneal cells, whether corneal cell polyamines can be depleted by blocking the first rate-limiting enzyme in the polyamine synthesis pathway, ornithine decarboxylase (ODC), and whether polyamines are required for proliferation in all three corneal cell types. METHODS Cultured corneal epithelial cells, keratocytes, and endothelial cells we...

Wild-type Escherichia coli cells grow normally in 95% O(2)/5% CO(2). In contrast, cells that cannot make polyamines because of mutations in the biosynthetic pathway are rapidly killed by incubation in 95% O(2)/5% CO(2). Addition of polyamines prevents the toxic effect of oxygen, permitting cell survival and optimal growth. Oxygen toxicity can also be prevented if the growth medium contains an a...

Polyamines are small organic bases that have been found in all living organisms where they play important roles in the regulation of growth, development and responses to biotic and abiotic stimuli. They do so by modulating a variety of cellular processes such as cell division, expansion, differentiation, death, nucleic acids, and protein synthesis and function. This diversity of functions deriv...