Zinc Supply Affects Cadmium Uptake and Translocation in the Hyperaccumulator Sedum Plumbizincicola as Evidenced by Isotope Fractionation.

This study employs stable isotope analysis to investigate the mechanisms of cadmium (Cd) and zinc (Zn) interaction in the metal hyperaccumulating plant species Sedum plumbizincicola. To this end, the Cd and Zn isotope compositions of root, stem, leaf, and xylem sap samples were determined during metal uptake and translocation at different Cd and Zn concentrations. The enrichment of light isotopes of both elements in plants during uptake was less pronounced at low metal supply levels, likely reflecting the switch from a low-affinity to a high-affinity transport system at lower levels of external metal supply. The lower δ114/110Cd values of xylem sap when treated with a metabolic inhibitor decreasing the active Cd uptake further supports the preference of heavier Cd isotopes during high-affinity transport. The Δ66Znplant-initial solution or Δ66Znplant-final solution values were similar at different Cd concentrations, indicating negligible interaction of Cd in the Zn uptake process. However, decreasing Zn supply levels significantly increased the enrichment of light Cd isotopes in plants (Δ114/110Cd = -0.08‰) in low-Cd treatments but reduced the enrichment of light Cd isotopes in plants (Δ114/110Cd = 0.08‰) under high Cd conditions. A systematic enrichment of heavy Cd and light Zn isotopes was found in root-to-shoot translocation of the metals. The Cd concentrations of the growth solutions thereby had no significant impact on Zn isotope fractionation during root-to-shoot translocation. However, the Δ114/110Cdtranslocation values hint at possible competition between Cd and Zn for transporters during root-to-shoot transfer and this may impact the transport pathway of Cd. The stable isotope data demonstrate that the interactions between the two metals influenced the uptake and transport mechanisms of Cd in S. plumbizincicola but had little effect on those of Zn.

Biological effects of static magnetic fields and zinc isotopes on E. coli bacteria.

The sensitivity of intracellular enzymatic systems to static magnetic fields (SMFs) and magnetic isotopes has been shown both in vitro and in vivo. These effects are determined by the spin-dependent magnetosensitive stages of enzymatic reactions. The search for experimental evidence of the combined effect of SMFs and zinc magnetic isotope 67 Zn on the intracellular processes on Escherichia coliEscherichia coli bacteria has taken place in vivo. The joint effects of external SMFs and magnetic zinc isotope 67 Zn on vital functions of E.coli bacteria have been shown experimentally. The combined effect of isotope 67 Zn and weak SMFs (25-35 mT) causes a 2-4-fold increase in the colony-forming ability and growth rate constants of bacteria E. coli compared with nonmagnetic zinc isotopes 64,66 Zn. The effects of SMFs in the range of 2.2-8 mT were detected for all bacteria, regardless of zinc isotope content in the media. An increase in ATP concentration in E. coli was detected for bacteria grown on a medium with the magnetic isotope 67 Zn in the SMF range of 2.2-4.2 mT. The major elements' (Na, K, Ca, Mg, P, Zn) metabolism in E. coli depend on the intensity of SMFs and zinc isotopes. These data confirm the existence of intracellular enzymatic processes stages that are sensitive to SMFs and magnetic moments of atomic nuclei. It is important to note that magnetic zinc 67 Zn and magnesium 25 Mg isotopes induce effects on viability of E. coli in different SMF ranges. Bioelectromagnetics. 40:62-73, 2019. © 2018 Wiley Periodicals, Inc.

Magnetosensitivity of E. coli Bacteria in the Presence of Zinc Isotopes.

The combined effect of the zinc magnetic isotope 67Zn and weak magnetic field 25-35 mT causes a 2-4-fold increase in the colony-forming ability of bacteria E. coli in comparison with the nonmagnetic isotopes 64, 66Zn. The effects of magnetic field in the range of 2.2-8 mT were detected for all bacteria regardless of the zinc-isotope enrichment of the media. This indicates the sensitivity of intracellular processes to weak magnetic fields. An increase in the ATP concentration in E. coli cells was only detected for the bacteria grown on the medium with the magnetic zinc isotope in the range of 2.2-4.2 mT. The obtained data confirm the existence of stages of intracellular enzymatic processes that are sensitive to magnetic fields and magnetic moments of atomic nuclei.

[Trace elements in human nutrition: biological indices of zinc insufficiency].

The review, discusses current data on biological indices that respond specifically to changes in Zn safety. The most reliable is the method of Zn safety evaluation based on its stores in organism measurement by means of stable isotopes. Zn status estimation by its levels determination in different kinds of available biological material (plasma, serum and whole blood, saliva, sweat, urine, hair, tissue samples) has different limitations. Some advances have so named physiological Zn safety criteria however their use is poorly validated or complicated with estimations subjectivity. Currently the first place belongs to a group of methods based on measurement of Zn-dependent proteins levels or activities together with their genes expression especially for such Zn-dependent enzyme as alkaline phosphatase.