No abstract

No abstract

An effect of the Aii(II1) energy dependent concentration has been discovered by living ChZweZZa cells. The process 11s most intensive within the alkaline interval of pH, fading away in the dark, and is suppressed in the presence of arsenate (C 1 FM), fluorides (C 1 0.01 mM), sodium azide (1 mM), DCCD (10 pM), 2,4-dinitrophenol (0.1 mM). I n the dark the process is stimulated b y BTP (but not by ADP, or AIIP). ATP also neutralizes NaN, effect, but not that of DNP. An energy dependent AulIII) concentration is also observed for other green, blue-green, and, red singlecell algae.Inactivated algal biomass has various functional groups. Due to this fact it can sorb a great number of heavy metals [l-41. This peculiarity has been used in the sorbent construction for the recovery of the metal from solutions [5-'71. I n this case a physicochemical sorption is the principle of metal immobilization. But it is well-known that cells effectively redistribute between intra and extracellular media and several vital elements which are of great physiological importance (K, Na, Xg, Ca), while the sorption of such metals by cellular structures is rather small. On the other hand, various elements (Cu, Fe, etc. [S, 81) are effectively bound to algal biomass. The cell needs these elements in microamounts. Besides, some cells may bind the elements, for example, 81, Au [3, 81 that were not observed to participate in biochemical processes. It had been noticed that the values of heavy metal accumulation by intact and inactivated cells were essentially different [ 101. The latter is evidence of the importance of physiological processes and the cells interacting with heavy metals. Moreover, the comparison between liophilized Chlorella biomass ability to bind such element as Au [3] and living cells effectiveness in this process [9] showed that, firstly, the result was higher when living cells were used, and secondly, in the last case the sorption process can be controlled. So the aim of this study -to investigate the appropriateness of ionic gold concentration by functionally a.ctive Chlorella cells -was stipulated by the differences between living and inactivated Chlorella cells discovered. Besides, it has been taken into account that the sorption characteristics of liophilized Chlorella biomass for several gold compleses were presented in [3].

No abstract

The inhibitory effect of Cu on glucose-dependent H+ efflux from Saccharomyces cerevisiae was manifest at low (micromolar) concentrations, with the time period between the addition of glucose and commencement of H+ efflux, H+ efflux rate and duration all being affected with increasing Cu concentration (5-100 microM). Ca, at a concentration of 0.5 mM, completely removed the inhibitory effect of Cu at concentrations up to 50 microM and considerably reduced it at higher concentrations (up to 150 microM). Mg exhibited a similar but weaker protective effect against the influence of Cu. The protective effect of Ca against 50 microM Cu was evident at low Ca concentrations (2.5-5 microM), whereas Mg was effective at > or = 50 microM. In order to prevent the inhibitory effect of Cu, it was necessary to add Ca or Mg to the cell suspension before Cu addition. It is concluded that the protective effect of Ca and Mg is mediated by competitive and stabilizing interactions at the cell surface as well as physiological functions of Ca and Mg.