Topic
Polyamine binding
About: Polyamine binding is a research topic. Over the lifetime, 188 publications have been published within this topic receiving 9206 citations.
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TL;DR: It is proposed that in addition to a slow gating mechanism producing long lasting open and closed states, there is a distinct, intrinsic fast gating process amplified by cytoplasmic Mg2+ and/or polyamine binding to the channel.
40 citations
TL;DR: The results suggest that spermidine-induced decrease of Na(+),K(+)-ATPase activity involves NMDA receptor/NOS/cGMP/PKG pathway.
39 citations
TL;DR: It is suggested that polyamines binding to the co-operative sites is associated with tertiary structure formation and that polyamine and divalent metal ion interactions with tRNA occur by phenomenologically similar mechanisms, in spite of their structural diversity.
39 citations
TL;DR: Uptake studies in seawater showed that polyamine accumulation in algal cells occurred and that it followed a concentration gradient and displayed linear kinetics, and the mechanism proposed that of a passive uptake, as indicated also by the inability of metabolic inhibitors to block transport.
Abstract: The excessive growth of Ulva rigida C. Agardh, a green seaweed present in the Northern Adriatic Sea, is a problem for the inhabitants and the economy of the region. As information about hormonal control of growth in seaweeds is scarce, our aim was to investigate the presence of endogenous polyamines and their absorption by algal cells and to correlate the findings with terrestrial plants. Free polyamines (putrescine, spermidine, and spermine) were present endogenously in the algal thallus at concentrations ranging from 4 to 134 μM. Putrescine and spermidine were also present in the seawater in which the alga usually grows at concentrations between 0 and 0.9 μM. Uptake of labeled polyamines occurred, but it was inhibited by cations present in the seawater. Uptake was investigated also by incubation in distilled water. In this case, uptake displayed characteristics similar to those observed in higher plant systems. Uptake studies in seawater showed that polyamine accumulation in algal cells occurred and that it followed a concentration gradient and displayed linear kinetics. The mechanism proposed that of a passive uptake, as indicated also by the inability of metabolic inhibitors to block transport. There was evidence for polyamine binding to external cell sites, but polyamine uptake by protoplasts as well as polyamine translocation and secretion by the whole thallus was also demonstrated. Since cultured and actively growing thallus discs displayed a higher uptake ability than freshly collected ones, a role for polyamines in sustaining growth is discussed.
39 citations
TL;DR: Putrescine, spermidine and spermine are natural components of carrot cell primary walls and their content depends on the age of the culture and is affected by different pH values and by the presence of Ca 2+ during wall extraction.
38 citations