Changes in Cadmium Concentration in Muscles, Ovaries, and Eggs of Silver European Eel (Anguilla anguilla) during Maturation under Controlled Conditions

This study determined the contents of cadmium (Cd) in the muscles, ovaries, and eggs of silver female European eels. The analysis of cadmium content was performed on female European eels caught during commercial fishing in freshwater in Warmia and Mazury (Poland), and then subjected to artificial maturation and ovulation processing under controlled conditions. The content of cadmium (Cd) in the tissues was determined by flameless atomic spectrometry using an electrothermal atomizer. The analysis showed statistically significant differences between the cadmium content in the muscles, ovaries, and eggs (p < 0.05) of female European eels. The lowest cadmium content was found in the muscle tissue (0.0012 ± 0.0001 mg kg−1 wet weight) and the highest in eggs (after ovulation) (0.0038 ± 0.0007 mg kg−1 wet weight). Moreover, a relationship was found between the cadmium content in the muscle tissue and the ovaries (R = 0.673; p = 0.0117) in the same fish. The movement of cadmium from tissues to oocytes may indicate a significant problem concerning this heavy metal content in the reproduction of European eel.

Artificial maturation of [FeFe] hydrogenase in a redox polymer film

We demonstrate that the insertion of the dinuclear active site of [FeFe] hydrogenase into the apo-enzyme can occur when the enzyme is embedded in a film of redox polymer, under...

Results of 13c nmr and ftir spectroscopy of kerogen of the upper devonian domanik of the Timan-Pechorian basin

A kerogen samples set from organic carbon rich rocks of the Middle Frasnian Early Famennian age (Domanikites) of the Timan-Pechora basin, was characterized by the Rock-Eval pyrolysis data, solid-state 13C NMR spectroscopy and Fourier transform IR spectroscopy. Additionally, the spectral characteristics of kerogen isolated from rocks artificially maturated in an autoclave in the presence of water were investigated. In general, the direction of transformation of the kerogen structure with a natural or artificial maturation coincides. For kerogen, subjected to artificial maturation, is characterized by an increase in the concentration of terminal methyl groups in relation to the methylene units. Artificial maturation of kerogen leads to a more rapid rearrangement of aromatic clusters with the accumulation of bridgehead and protonated carbon as compared with natural maturation.