No abstract

Human prion protein (hPrP) fragments encompassing the 91-120 region, namely hPrP92-100 (SP1), hPrP106-113 (SP2), hPrP91-120 (LP1), and hPrP91-114 (LP2), were considered for delineation of the Cu(II)-binding site(s). NMR and EPR spectroscopy results obtained from LP1 or LP2 were compared with those obtained from SP1 and SP2. The coexistence of two binding sites, one centered at His96 and the other at His111, was evidenced and ratified by ESI mass spectrometry at low and high metal:peptide ratios. While room-temperature NMR spectroscopy data were consistent with the binding site centered on His111 being approximately fourfold stronger than that centered on His96, low-temperature EPR spectroscopy results yielded evidence for the opposite trend. This disagreement, which has also occurred in the literature, was clarified by temperature-dependent molecular dynamics runs that demonstrated Met112 approaching the metal at room temperature, a process that is expected to stabilize the His111-centered binding site through hydrophobic shielding of the metal coordination sphere.

The copper(II) binding features of the APP(145-155) and APP(145-157) fragments of the amyloid precursor protein, Ac-Glu-Thr-His-Leu-His-Trp-His-Thr-Val-Ala-Lys-NH2 and Ac-Glu-Thr-His-Leu-His-Trp-His-Thr-Val-Ala-Lys-Glu-Thr-NH2 were studied by NMR spectroscopy and NMR findings were supported by UV-vis, CD and EPR spectra. Potentiometric measurements were performed only for the more soluble Ac-Glu-Thr-His-Leu-His-Trp-His-Thr-Val-Ala-Lys-Glu-Thr-NH2 peptide fragment. The following was shown: (i) the imidazole rings of all the three His residues are involved in metal coordination; (ii) metal binding induces ionisation of Leu-148 and His-149 amide nitrogens that complete the donor set to copper(II) in the species dominant at neutral pH; (iii) the unusual coordination scheme of the His-Xxx-His-Xxx-His consensus sequence justifies the high specificity for Cu(II) when compared to SOD-like or albumin-like peptides or even in amyloid Abeta fragments. The present findings may represent the key for interpreting the observed requirement of His residues conservation for the redox cycling between Cu(II) and Cu(I) by soluble APP.

Prion diseases are characterized by a structural modification of the regular prion protein (PrP(C)) to its isoform, termed PrP(Sc)(scrapie). Such a modification involves the secondary and tertiary structure of the protein; the amino acidic sequence remains unchanged. PrP(Sc) is almost insoluble in non-denaturing solvents, resistant to proteases and it loses its redox activity. PrP(C) is able to bind copper and other metal ions: these complexes have been suggested to play an important role in the protein refolding leading to PrP(Sc). It is well-known that at least one relatively strong copper-binding site is located in the PrP(92--126) domain, where two His residues (96 and 111) are present. However, in the same domain, other amino acidic residues bear potentially donating atoms, i.e. Met, Asn and Lys residues. In order to shed light on the role of the side chains of such potentially tridentate amino acids on copper complexation, the polypeptide Ac-KTNMKHMA-NH(2), corresponding to the PrP(106--113) fragment, and some synthetic analogues have been investigated as ligands for the copper ion, by means of both thermodynamic and spectroscopic techniques. The pivotal role of imidazolic side chain of His in "anchoring" the metal ion has been confirmed. On the other hand, no clue was found on the participation of sulfur atom of Met or side amino-group of Lys residues to copper complex-formation.

Legal restrictions on vehicle engine exhaust gas emission control do not always go hand in hand with an actual reduction in the emissions of toxins into the atmosphere. Moreover, the methods currently used to measure exhaust gas emissions do not give unambiguous results on the impact of the tested gases on living organisms. The method used to assess the actual toxicity of gases, BAT-CELL Bio-Ambient-Tests using in vitro tests, takes into account synergistic interactions of individual components of a mixture of gases without the need to know its qualitative and quantitative composition and allows for determination of the actual toxicity of the gas composition. Using the BAT-CELL method, exhaust gases from passenger vehicles equipped with spark-ignition engines complying with the Euro 3 and Euro 6 emission standards were tested. The results of toxicological tests were correlated with the results of chromatographic analysis. It was shown that diverse qualitative composition of the mixture of hydrocarbons determining the exhaust gases toxicity may decrease the percentage value of cell survival. Additionally, it was proven that the average survival of cells after exposure to exhaust gases from tested vehicles meeting the more restrictive Euro 6 standard was lower than for vehicles meeting the Euro 3 standard thus indicating the higher toxicity of exhaust gases from newer vehicles.

The automotive industry is one of the fastest-growing sectors of the modern economy. Growing customer expectations, implementing solutions related to electromobility, and increasingly stringent legal restrictions in the field of environmental protection, determine the development and introduction of innovative technologies in the field of car production. To power the most modern vehicles that include electric and hybrid cars, packages of various types of lithium-ion cells are used, the number of which is constantly growing. After use, these batteries, due to their complex chemical composition, constitute hazardous waste that is difficult to manage and must be recycled in modern technological lines. The article presents the morphological characteristics of the currently used types of Li-ion cells, and the threats to the safety of people and the environment that may occur in the event of improper use of Li-ion batteries and accumulators have been identified and described on the basis of the Regulation of the European Parliament and Council (EC) No. 1272/2008 of 16 December 2008 and No. 1907/2006 of 18 December 2006 on the classification, labeling and packaging of substances and mixtures and the registration, evaluation, authorization and restriction of chemicals (REACH), establishing the European Chemicals Agency.

In the next decade, due to the desire for significant reduction in the carbon footprint left by the aviation sector and the development of a sustainable alternatives to petroleum, fuel from renewable sources will play an increasing role as a propellant for turbine aircraft engines. Currently, apart from five types of jet fuel containing synthesized hydrocarbons that are certified by the ASTM D7566 standard, there is yet another synthetic blending component that is at the stage of testing and certification. Hydroprocessed esters and fatty acids enable the production of a synthetic component for jet fuel from any form of native fat or oil. Used feedstock affects the final synthetic blending component composition and consequently the properties of the blend for jet fuel and, as a result, the operation of turbine engines. A specialized laboratory test rig with a miniature turbojet engine was used for research, which is an interesting alternative to complex and expensive tests with full scale turbine engines. The results of this study revealed the differences in the parameters of engine performance and emission characteristics between tested fuels with synthetic blending components and neat jet fuel. The synthetic blending component was obtained from two different feedstock. Noticeable changes were obtained for fuel consumption, CO and NOx emissions. With the addition of the hydroprocessed esters and fatty acids (HEFA) component, the fuel consumption and CO emissions decrease. The opposite trend was observed for NOx emission. The tests presented in this article are a continuation of the authors’ research area related to alternative fuels for aviation.

Purpose The purpose of this paper is to examine the toxicological impacts of exhaust generated during the combustion process of aviation fuel containing synthesized hydrocarbons. Design/methodology/approach Tests on aircraft turbine engines in full scale are complex and expensive. Therefore, a miniature turbojet engine was used in this paper as a source of exhaust gases. Toxicity was tested using innovative BAT–CELL Bio–Ambient Cell method, which consists of determination of real toxic impact of the exhaust gases on the human lung A549 and mouse L929 cells. The research was of a comparative nature. The engine was powered by a conventional jet fuel and a blend of conventional jet fuel with synthesized hydrocarbons. Findings The results show that the BAT–CELL method allows determination of the real exhaust toxicity during the combustion process in a turbine engine. The addition of a synthetic component to conventional jet fuel affected the reduction of toxicity of exhaust gases. It was confirmed for both tested cell lines. Originality/value In the literature related to the area of aviation, numerous publications in the field of testing the emission of exhaust gaseous components, particulates or volatile organic compounds can be found. However, there is a lack of research related to the evaluation of the real exhaust toxicity. In addition, it appears that the data given in aviation sector, mainly related to the emission levels of gaseous exhaust components (CO, Nox and HC) and particulate matters, might be insufficient. To fully describe the engine exhaust emissions, they should be supplemented with additional tests, i.e. in terms of toxicity.