Effects of lead and selected pyrethroids/piperonyl butoxide alone and in combination on Na,K‐ATPase

In vitro effects of Pb²⁺, the pyrethroid insecticides cypermethrin, fenvalerate and the syner‐gist piperonyl butoxide on sodium‐potassium‐activated adenosine triphosphatase (Na,K‐ATPase) from dog kidney were determined. Pb²⁺ with an estimated IC50 value of 5.2 μM was found to be a potent inhibitor of Na,K‐ATPase activity, whereas Na,K‐ATPase was less sensitive to the pyrethroids tested and piperonyl butoxide. Investigation with circular dichroism (CD) spec‐troscopy showed that inhibition occurs through conformational changes of the α‐subunit of the enzyme. The kinetic characteristics of inhibition of Na,K‐ATPase with varying substrate (ATP) concentrations as well as with varying Na⁺ concentrations exhibited a competitive type of inhibition with Pb²⁺ in the μM range. With Pb²⁺ alone in the enzyme assay no conformational changes of the protein could be observed which confirmed the assumption that Pb²⁺ can bind to the Na⁺ binding site of the α‐subunit. Uncompetitive type of inhibition occurred with varied K⁺ concentrations demonstrating that this cation binding site is not affected directly by Pb²⁺.

Complete reversal of Pb²⁺ by DTT confirms that a possible target for interaction of this heavy metal ion with Na, K‐ATPase are specific SH groups.

Synergistic effects could only be determined with higher Pb²⁺ concentrations of 3, 5 and 7 μM plus piperonyl butoxide while all other combinations with this heavy metal plus organic substances where of the additive type. With CD spectroscopy also only additive effects were observed. These results demonstrate that higher concentrations of piperonyl butoxide favor the binding of Pb²⁺ to the Na⁺ binding site by conformational changes of the protein.     

Temporal trend (1988-2008) of hexabromocyclododecane enantiomers in herring gull eggs from the German coastal region

Levels of α-, β-, and γ-hexabromocyclododecane (HBCD) were determined in pooled eggs from herring gulls (Larus argentatus) sampled on three bird sanctuaries near the German North Sea coast between 1988 and 2008 (Mellum and Trischen) and the German Baltic Sea coast between 1998 and 2008 (Heuwiese) and archived by the German Environmental Specimen Bank. Pressurized fluid extraction, gel permeation chromatography, and LC-MS/MS using ¹³C₁₂-labelled isotope standards and a chiral column were applied. α-HBCD was the dominating diastereomer and ranged between 3.7 and 107 ng g⁻¹ lw while β- and γ-HBCD were throughout close to LOQ. The highest α-HBCD concentration was found in eggs from Mellum sampled in the year 2000. Interestingly, HBCD in eggs from the three islands displayed similar time courses with levels increasing to a peak contamination around 2000 and decreasing levels ever since. Chiral signatures of α-HBCD in eggs differed among the islands but indicated a preferential enrichment of the first eluting enantiomer (−)-α-HBCD.     

The phylogeny of archaebacteria,including novel anaerobic thermoacidophiles in the light of RNA polymerase structure

DNA-dependent RNA polymerases of archaebacteria are distinct from those of eubacteria both in structure and in function. They show similarities to those of the eukaryotic cytoplasm. Extremely thermophilic anaerobic sulfur-respiring archaebacteria isolated from solfataric waters represent four different families, the Thermoproteaceae, the “stiff filaments”, the Desulfurococcaceae and the Thermococcaceae, of a novel order, Thermoproteales. Together with the Sulfolobales, they form the second branch of the urkingdom of the archaebacteria besides that of the methanogens and extreme halophiles. Thermoplasma appears isolated.     

Analysis of chlorinated paraffins in cutting fluids and sealing materials by carbon skeleton reaction gas chromatography

Chlorinated paraffins (CPs) pose a major risk in the environment, due to their wide application, to their persistence, to their carcinogenic potential, and in view of the fact, that they cannot be easily identified. Various commercial cutting fluids and sealing materials were analysed for CPs with carbon skeleton reaction gas chromatography (GC) and flame ionization detection. CPs are simultaneously dechlorinated and hydrogenated to the corresponding alkanes with Pd catalyst material in the GC injector. With this method, the carbon chain length of commercial technical CPs was determined. In six of sixteen sealing materials we found five short and one medium chain length polychlorinated paraffins in percentages of 9-16% (w/w). In five cutting fluids we found predominantly medium to long chain length chloroparaffins with percentages of 2.5-31% (w/w), only one fluid contained short chain CPs.     

Quantifying ozone uptake and its effects on the stand level of common beech (Fagus sylvatica L.) in Southern Germany

Stand level O(3) fluxes were calculated using water balance calculations for 21 Common beech (Fagus sylvatica L.) stands and O(3) data from 20 monitoring stations in Southern Germany. For this intention, the daily loss of water by evapotranspiration per stand area was set against the daily O(3) uptake. During the last 30 years, O(3) uptake ranges between 0 and 187 mmol ha(-1) d(-1) per stand area. Cumulative O(3) uptake (CUO(3)), ranging between 0.1 and 0.7 mmol m(-2) yr(-1) per stand area, shows increasing trends since 1971 with considerably greater values at high altitudes. Effects in radial growth were used to derive an initial approximate critical threshold value for O(3) impacts on the vitality and growth of mature beech stands in Southern Germany. It is concluded that this concept of O(3) flux estimation in combination with dendroecological analyses offers both a site specific and regional applicable approach to derive new critical levels for O(3).     

Defining Chlorophyll-a Reference Conditions in European Lakes

The concept of “reference conditions” describes the benchmark against which current conditions are compared when assessing the status of water bodies. In this paper we focus on the establishment of reference conditions for European lakes according to a phytoplankton biomass indicator—the concentration of chlorophyll-a. A mostly spatial approach (selection of existing lakes with no or minor human impact) was used to set the reference conditions for chlorophyll-a values, supplemented by historical data, paleolimnological investigations and modelling. The work resulted in definition of reference conditions and the boundary between “high” and “good” status for 15 main lake types and five ecoregions of Europe: Alpine, Atlantic, Central/Baltic, Mediterranean, and Northern. Additionally, empirical models were developed for estimating site-specific reference chlorophyll-a concentrations from a set of potential predictor variables. The results were recently formulated into the EU legislation, marking the first attempt in international water policy to move from chemical quality standards to ecological quality targets.     

Regional Industries and Environmental Impacts. Long-run Regional Economic Effects of Climate Change: The Case of the Coastal and Estuary Zone of the German Northwest

The paper explores the relations of (1) regionalized climate change impulses; (2) their impacts on regional industry sectors; and (3) a regional econometric impact analysis. It develops a methodology by which the impulses of a regional climate change scenario can be transformed into ‘primary’ impacts on the capital stock and value added of climate-sensitive regional industries. These industries are vulnerable to ‘creeping’, i.e. continuous, climate change impulses, and they tend to react through ‘defensive’ investment. In addition, a singular flooding event is simulated for a specific local area and its different capital stocks. The stock damages and value-added losses of both the continuous industrial impacts and the singular flooding are inserted into a regional econometric model. This is sectorally disaggregated in stock, value-added and investment functions. It is also calibrated in the very-long run (through to the year 2040), according to different scenarios. The regional economic ‘secondary’ effects on the regional GNP are calculated. In addition to the calculation of regional economic primary and secondary impacts, the methodological issue of generating more transparency of the causal chains by use of damage functions, reaction functions, and comparative defensive strategies are discussed.