Sanierungsforschung in regional kontaminierten Aquiferen (SAFIRA) – 2. Projektüberblick und Pilotanlage

The joint research project SAFIRA, which is supported by the Federal Ministry of Science and Education (BMBF), deals with the development of innovative technologies for the in situ remediation of heavily contaminated groundwater at the in situ pilot facility in Bitterfeld. In order to evaluate the new promising technological approaches comprehensively, methodological tools are developed to comparatively address economical, ecological as well as a environmental issues of related remediation scenarios. The design period for innovative technologies can hardly be forecasted and/or its success be guaranteed. To prove a long-term stability as well as to reach a sound economical and ecological evaluation for new approaches an on site operation over extended periods of time is needed. Therefore a variety of technologies are tested and optimized simultaneously, in order to achieve a thorough comparison of technologies at the end of the project.     

Xenobiotics in groundwater and surface water of the city of Leipzig

Xenobiotics are increasingly being considered as ecotoxicologically relevant for the aquatic environment and human health. Their behaviour and the effects on the environment have not yet been comprehensively investigated and, therefore, are currently the subject of the project WASSER Leipzig initiated by the UFZ. The results of this article are based on groundwater and surface water analyses of a watershed within the town of Leipzig. Here the industrial chemicals bisphenol-A and t-nonylphenol, the polycyclic fragrances galaxolide and tonalide, the antiepileptic drug carbamacepine and caffeine where investigated. Xenobiotics showed ubiquitous occurrence in the rivers, which were contaminated from treated and untreated sewage, as well as in groundwater, contaminated by leaky sewers. Mean concentrations up to several hundred ng/l were found in the rivers, while groundwater concentrations, except for bisphenol-A, tended to be lower. Applying the statistical factor analysis on the hydrochemical measurements, a differentiation of the xenobiotics with regard to their hydrochemical behaviour in groundwater was performed.     

Development of a method for the quantification of the molar gold concentration in tumour cells exposed to gold-containing drugs

The knowledge of the cellular molar concentration of a drug is an extremely important parameter for the discussion and interpretation of its efficacy and bioavailability. Concerning metal complexes, electrothermal atomic absorption spectroscopy (ETAAS) offers a valuable analytical tool. However, matrix effects often hamper proper quantification of the metal concentration in biological tissues. This paper describes the development of an ETAAS method for the quantification of the molar gold concentration in HT-29 colon carcinoma cells. ETAAS analytical conditions were optimised and a factor was developed which allows the calculation of the molar cellular gold concentration from the measured gold per cellular biomass value. The method was used to quantify the gold content in HT-29 cells after exposure to the gold drug auranofin. Results indicated a strong cellular uptake of auranofin (compared to other metal anticancer drugs), which significantly correlated with the antiproliferative effects triggered by this agent.     

Product Engineering am Beispiel extrudierter Instantpulver

Product Engineering in the Case of Extruded Instant Powders . Starch based instant powders are usually produced by cooking/gelatinizing in an excess of water with subsequent drying and milling. Important product attributes are the specific weight and the instant properties of the powder, as well as the taste, the viscosity, and the mouth-feel of the reconstituted gel. Cooking extrusion is an alternative energy saving process. Process development usually takes a long time and proves expensive due to the large number of different process parameters and their possible combinations. For two exemplary products it is demonstrated how the screw configuration and the target range of process parameters can be defined by statistical trial design. Final optimization (?fine tuning”?) and scale-up assure efficient process design according to product needs.     

Involvement of GPR17 in Neuronal Fibre Outgrowth

Characterization of new pharmacological targets is a promising approach in research of neurorepair mechanisms. The G protein-coupled receptor 17 (GPR17) has recently been proposed as an interesting pharmacological target, e.g., in neuroregenerative processes. Using the well-established ex vivo model of organotypic slice co-cultures of the mesocortical dopaminergic system (prefrontal cortex (PFC) and substantia nigra/ventral tegmental area (SN/VTA) complex), the influence of GPR17 ligands on neurite outgrowth from SN/VTA to the PFC was investigated. The growth-promoting effects of Montelukast (MTK; GPR17- and cysteinyl-leukotriene receptor antagonist), the glial cell line-derived neurotrophic factor (GDNF) and of two potent, selective GPR17 agonists (PSB-16484 and PSB-16282) were characterized. Treatment with MTK resulted in a significant increase in mean neurite density, comparable with the effects of GDNF. The combination of MTK and GPR17 agonist PSB-16484 significantly inhibited neuronal growth. qPCR studies revealed an MTK-induced elevated mRNA-expression of genes relevant for neuronal growth. Immunofluorescence labelling showed a marked expression of GPR17 on NG2-positive glia. Western blot and RT-qPCR analysis of untreated cultures suggest a time-dependent, injury-induced stimulation of GPR17. In conclusion, MTK was identified as a stimulator of neurite fibre outgrowth, mediating its effects through GPR17, highlighting GPR17 as an interesting therapeutic target in neuronal regeneration.     

Novel building blocks for oligonuclear copper complexes derived from β‐ketoenamines of histidine

Condensation products of L‐histidine with the 3‐oxoenolethers diethyl‐ethoxymethylene‐malonate ( 1 ) and ethyl‐ethoxymethylene‐cyanoacetate ( 2 ) react with copper(II) as di‐anionic ligands to give neutral 1:1 complexes Cu‐ His1 and Cu‐ His2 . Both complexes crystallize as oligonuclear units, even from strongly donating solvents like N‐methylimidazole (Meim) (Cu‐ His1 ) and pyridine (Cu‐ His2 ). X‐ray structure analyses show supramolecular structures, formed of two (Cu‐ His1 ) or four (Cu‐ His2 ) formula units of the complex, which arrange to macrocycles by means of intermolecular coordination of the imidazole‐N. Strong H‐bridges result in a face‐to‐face orientation of the hydrophilic sites of two great rings. ESI‐MS investigations in pyridine solution give evidence for the existence of dimeric, tetrameric and – in case of Cu‐ His2 – trimeric units, besides the monomeric adducts with one pyridine. In contrast to the dimeric or tetrameric (“cubane‐like”) copper(II) complexes of amino alcohols and their β‐ketoenamines, the complexes Cu‐ His1 and Cu‐ His2 show no significant spin coupling from room temperature down to 4 K. The complexes Cu‐ His1 and Cu‐ His2 give no electrochemically reversible Cu^II/I reduction in pyridine. However, the isolation of a stable diamagnetic copper(I) complex of the methylester derivative, Cu^I‐ HisMe1 , supports the assumption, that similar histidine‐derived copper complexes should display reversible redox behaviour and catalytic activity in reactions with O₂.