![]() ![]() Caesium transport in the cyanobacterium Anabaena variabilis: kinetics and evidence for uptake via ammonium transport system(s). In: Impact of Heavy Metals on the Environment (Vernet, J.-P., ed.), pp. Interactions of cyanobacteria and microalgae with caesium. Caesium accumulation and interactions with other monovalent cations in the cyanobacterium Synechocystis PCC 6803. Mechanism of adsorption of hard and soft metal ions to Saccharomyces cerevisiae and influence of hard and soft anions. Microbial interactions with caesium-implications for biotechnology. Discrimination between alkali metal cations by yeast. 161–176, Blackwell, Oxford.Īrmstrong, W.McD. Are there any potentially important routes whereby radionuclides can be transferred by biological processes from the sea-bed towards the surface? In: Ecological Aspects of Radionuclide Release (Coughtrey, P.J., J.N.B. Rubidium as a probe for function and transport of potassium in the yeast Candida utilis. Osmoregulation in the extremely euryhaline marine microalga Chlorella autotrophica. ribosomes, become unstable in the presence of Cs + and Cs + is known to substitute poorly for K + in the activation of many K +-requiring enzymes.Īhmad, I. The precise intracellular target(s) for Cs +-induced toxicity has yet to be clearly defined, although certain internal structures, e.g. ![]() Increased microbial tolerance to Cs + may result from sequestration of Cs + in vacuoles or changes in the activity and/or specificity of transport systems mediating Cs + uptake. However, stimulation of growth of K +-starved microbial cultures by Cs + is limited and its has been proposed that it is not the presence of Cs + in cells that is growth inhibitory but rather the resulting loss of K +. K +, Na +, NH 4 + and H +, and is generally accompanied by an approximate stoichiometric exchange for intracellular K +. Microbial Cs + accumulation is markedly influenced by the presence of external cations, e.g. These differe widely in specificity for alkali cations and consequently microorganisms display large differences in their ability to accumulate Cs + Cs + appears to have an equal or greater affinity than K + for transport in certain microorganisms. Microbial Cs + (K +) uptake is generally mediated by monovalent cation transport systems located on the plasma membrane. Although Cs + is a weak Lewis acid that exhibits a low tendency to form complexes with ligands, its chemical similarity to the biologically essential alkali cation K + facilitates high levels of metabolism-dependent intracellular accumulation. Caesium exists almost exclusively as the monovalent cation Cs + in the natural environment. The continued release of caesium radioisotopes into the environment has led to a resurgence of interest in microbe-Cs interactions. ![]()
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