| Autor: |
Salvatore MM; Department of Chemical Sciences, University of Naples Federico II, 80126 Naples, Italy.; Institute for Sustainable Plant Protection, National Research Council, 80055 Portici, Italy., Siciliano A; Department of Biology, University of Naples Federico II, 80126 Naples, Italy., Staropoli A; Institute for Sustainable Plant Protection, National Research Council, 80055 Portici, Italy.; Department of Agricultural Sciences, University of Naples Federico II, 80055 Portici, Italy., Vinale F; Institute for Sustainable Plant Protection, National Research Council, 80055 Portici, Italy.; Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, 80137 Naples, Italy.; BAT Center-Interuniversity Center for Studies on Bioinspired Agro-Environmental Technology, University of Naples Federico II, 80055 Portici, Italy., Nicoletti R; Department of Agricultural Sciences, University of Naples Federico II, 80055 Portici, Italy.; Council for Agricultural Research and Economics, Research Centre for Olive, Fruit and Citrus Crops, 81100 Caserta, Italy., DellaGreca M; Department of Chemical Sciences, University of Naples Federico II, 80126 Naples, Italy., Guida M; Department of Biology, University of Naples Federico II, 80126 Naples, Italy.; BAT Center-Interuniversity Center for Studies on Bioinspired Agro-Environmental Technology, University of Naples Federico II, 80055 Portici, Italy., Salvatore F; Department of Biology, University of Naples Federico II, 80126 Naples, Italy., Iuliano M; Department of Chemical Sciences, University of Naples Federico II, 80126 Naples, Italy., Andolfi A; Department of Chemical Sciences, University of Naples Federico II, 80126 Naples, Italy.; BAT Center-Interuniversity Center for Studies on Bioinspired Agro-Environmental Technology, University of Naples Federico II, 80055 Portici, Italy., De Tommaso G; Department of Chemical Sciences, University of Naples Federico II, 80126 Naples, Italy. |
| Abstrakt: |
Rare-earth elements (REEs) are in all respect a class of new contaminants that may have toxic effects on organisms and microorganisms and information on their interactions with natural ligands should be of value to predict and control their diffusion in natural environments. In the current study, we investigate interactions of tripositive cations of praseodymium, europium, holmium, and thulium with harzianic acid (H 2 L), a secondary metabolite produced by selected strains of fungi belonging to the Trichoderma genus. We applied the same techniques and workflow previously employed in an analogous study concerning lanthanum, neodymium, samarium, and gadolinium tripositive cations. Therefore, in the current study, HPLC-ESI-HRMS experiments, circular dichroism (CD), and UV-Vis spectrophotometric absorption data, as well as accurate pH measurements, were applied to characterize bonding interactions between harzianic acid and Pr 3+ , Eu 3+ , Ho 3+ , and Tm 3+ cations. Problems connected to the low solubility of harzianic acid in water were overcome by employing a 0.1 M NaClO 4 /(CH 3 OH + H 2 O 50/50 w / w ) mixed solvent. For Pr 3+ , Ho 3+ , and Tm 3+ , only the mono complexes PrL + , HoL + , and TmL + were detected and their formation constant determined. Eu 3+ forms almost exclusively the bis complex EuL2- for which the corresponding formation constant is reported; under our experimental conditions, the mono complex EuL + is irrelevant. Combining the results of the present and previous studies, a picture of interactions of harzianic acid with rare-earth cations extending over 8 of the 17 REEs can be composed. In order to complement chemical information with toxicological information, a battery of bioassays was applied to evaluate the effects of praseodymium, europium, holmium, and thulium tripositive cations on a suite of bioindicators including Aliivibrio fischeri (Gram-negative bacterium), Raphidocelis subcapitata (green alga), and Daphnia magna (microcrustacean), and median effective concentration (EC50) values of Pr 3+ , Eu 3+ , Ho 3+ , and Tm 3+ for the tested species were assessed. |
