Efficient Degradation of Aflatoxin B1 and Zearalenone by Laccase-like Multicopper Oxidase from Streptomyces thermocarboxydus in the Presence of Mediators

Multicopper oxidases (MCOs) are a diverse group of enzymes that could catalyze the oxidation of different xenobiotic compounds, with simultaneous reduction in oxygen to water. Aside from laccase, one member of the MCO superfamily has shown great potential in the biodegradation of mycotoxins; however, the mycotoxin degradation ability of other MCOs is uncertain. In this study, a novel MCO-encoding gene, StMCO, from Streptomyces thermocarboxydus, was identified, cloned, and heterologously expressed in Escherichia coli. The purified recombinant StMCO exhibited the characteristic blue color and bivalent copper ion-dependent enzyme activity. It was capable of oxidizing the model substrate ABTS, phenolic compound DMP, and azo dye RB5. Notably, StMCO could directly degrade aflatoxin B1 (AFB1) and zearalenone (ZEN) in the absence of mediators. Meanwhile, the presence of various lignin unit-derived natural mediators or ABTS could significantly accelerate the degradation of AFB1 and ZEN by StMCO. Furthermore, the biological toxicities of their corresponding degradation products, AFQ1 and 13-OH-ZEN-quinone, were remarkably decreased. Our findings suggested that efficient degradation of mycotoxins with mediators might be a common feature of the MCOs superfamily. In summary, the unique properties of MCOs make them good candidates for degrading multiple major mycotoxins in contaminated feed and food.

Сверхтонкие взаимодействия в узлах меди диэлектрических и сверхпроводящих металлооксидов меди

The method of Mössbauer spectroscopy on isotopes 61Cu (61Ni) shows that for bivalent copper dielectric metal oxides, a combined quadrupole and Zeeman interaction of 61Ni nuclei with local fields in copper sites is observed, whereas for superconducting metal oxides, only quadrupole interaction of the nuclei 61Ni is detected. For all the metal oxides under consideration, the equal in value valence contribution to the electric field gradient tensor was found.

Copper–lead selenite bromides: a new large family of compounds partly having Cu2+ substructures derivable from kagome nets

Extensive experiments in the Pb–Cu–Se–O–Br system at 400°C yielded single crystals of nine new compounds (Cu2+Pb6(SeO3)4Br6, Cu2+Pb2(SeO3)2Br2, Cu2+ 3Pb2.4(SeO3)5Br0.8, Cu2+ 2Pb(SeO3)2Br2, Cu2+ 4Pb(SeO3)4Br2, [Cu2+ 9Pb2O4](Cu+Br2)(SeO3)4Br5, [Cu2+ 7PbO3](Cu+Br)0.35(SeO3)3Br4, [Cu2+ 8Pb2O4](Cu+Br)1.5(SeO3)4Br4, [Cu2+ 6Pb3O4](Cu+Pb1.27Br3.54)(SeO3)4Br2), all but one exhibiting new complex layered or open-framework architectures, organized via the host–guest principle. Five of these structures contain only bivalent copper: three with well ordered 2D structures and completely filled atomic positions, two structures have 3D frameworks. The four remaining compounds contain both, Cu2+ and Cu+, and comprise layers formed by edge- and vertex-sharing of oxocentered OCu2+ 4–n Pb n tetrahedra decorated with SeO3 2− and Br− anions. The interlayer spaces are filled by partially disordered Cu+–Br and Pb–Br associations. One remarkable feature of the latter group of compounds is the presence of tetrahedral (Cu2+)4 complexes with arrangements derivable from a kagome network.

Ecological aspects of heavy metals accumulation in higher aquatic plants in the process of phytoremediation

This paper deals with pollution of natural and waste waters with heavy metals in the conditions of technogenic impact. It describes one of the numerous methods for neutralizing various contaminants in the aquatic environment, in particular phytoremediation, which has been used for more than 50 years in various countries. The paper considers the role of higher aquatic plants which, according to a variety of confirmatory studies, can be used to extract toxic components from natural and waste water - heavy metal ions. The authors consider a possibility of inorganic origin pollutants extraction with the help of higher water plants of Myriophyllum verticillatum L. and Elodea canadensis Michx. in laboratory conditions. The authors determined pollutants concentration change dependence in the solution with a process duration of less than 10 hours. The authors proved that the maximum purification efficiency is achieved only with the combined use of higher aquatic plants and perfetron. The results of the studies indicate a possibility of water purification from heavy metal ions (ferric iron, bivalent copper, bichromate ions) with the help of higher water plants Myriophyllum verticillatum L. and Elodea canadensis Michx.

Synthesis, Characterization, and Biological Evaluation of Unimetallic and Heterobimetallic Complexes of Bivalent Copper

We present an inclusive characterization of the unimetallic and heterobimetallic complexes of copper synthesized using CuCl2 and diamine (4-fluoro 1,2-phenylenediamine) resulting in monometallic complex which further undergoes treatment with organometallic dichlorides of group 4 and 14 in 1 : 2 molar ratio resulting in heterobimetallic complexes. These complexes thoroughly characterized using various physical, analytical, and spectroscopic techniques indicate square planar and distorted octahedral geometry for the synthesized unimetallic and heterobimetallic complexes, respectively. These complexes were evaluated for their antimicrobial efficacy against various bacterial and fungal strains while hepatoprotective activity was also examined in male albino rats.