Formation, characterization and release of non-extractable residues of [14C] -labeled organic xenobiotics in soils

The amount of non-extractable residues (NER) of organic xenobiotics in the soil can considerably exceed the amount of extractable residues which are accessible to normal residue analysis. The NER therefore present a burden to the soil, the toxicological and ecotoxicological potential of which is largely unknown. For the characterization of bound residues and their binding type, special solubilization methods such as supercritical fluid extraction are applied and experiments with radiolabeled model polymers are performed. Mineralization experiments with [¹⁴C] labeled xenobiotics in natural soil show that a total degradation is still also possible in the environment when in a bound form. Ecotoxicological effects of non-extractable residues may be recorded when their concentration is high, when the parent compound exhibits a high ecotoxicity and the applied detection method is sufficiently sensitive.     

Cnidosac morphology in dendronotacean and aeolidacean nudibranch molluscs: from expulsion of nematocysts to use in defense?

Nudibranchs (Mollusca, Gastropoda) feeding on tentacles and polyps of Cnidaria thereby ingest both latent and discharged nematocysts (NCs) along with the food mass. In eolid nudibranchs (Opisthobranchia, Aeolidacea), many of the undischarged NCs are transported to terminal cnidosacs in their body appendages (cerata) and incorporated as kleptocnidae for defense. In the present report, the occurrence and fate of NCs in the digestive tracts of eolids is compared with hydrozoan-feeding dendronotacean nudibranchs (Opisthobranchia, Dendronotacea), which may show more basic stages in the evolution of cnidosacs. Tomographic reconstructions of the distal tips of cerata were composed from series of semithin light microscopic sections, utilizing 3D-surface rendering software. Doto acuta (Dendronotacea, Dotidae) does not have cnidosacs; transmission electron micrographs show that the NCs are digested in lysosomes of digestive gland cells. In contrast, species of the genus Hancockia (Dendronotacea, Hancockiidae) have several small cnidosacs in each ceras; they accumulate NCs in the digestive cells, as well as in the cnidosacs. Many of the cnidosacs were found open to the exterior with NCs in the process of expulsion. These and other structural details suggest assigning a function of expelling the NCs to the Hancockia spp. cnidosacs. It is proposed that cnidosacs similar to those of Hancockia spp. provide a clue to understanding how the defensive function of eolid cnidosacs may have evolved. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Towards a spatially explicit and quantitative vulnerability assessment of environmental change in Europe

Over the next century, society will increasingly be confronted with the impacts of global change (e.g. pollution, land use changes, and climate change). Multiple scenarios provide us with a range of possible changes in socio-economic trends, land uses and climate (i.e. exposure) and allow us to assess the response of ecosystems and changes in the services they provide (i.e. potential impacts). Since vulnerability to global change is less when society is able to adapt, it is important to provide decision makers with tools that will allow them to assess and compare the vulnerability of different sectors and regions to global change, taking into account exposure and sensitivity, as well as adaptive capacity. This paper presents a method that allows quantitative spatial analyses of the vulnerability of the human-environment system on a European scale. It is a first step towards providing stakeholders and policy makers with a spatially explicit portfolio of comparable projections of ecosystem services, providing a basis for discussion on the sustainable management of Europe’s natural resources.

Molecular/chemical ecology in sponges: evidence for an adaptive antibacterial response in<Emphasis Type="Italic"> Suberites domuncula</Emphasis>

Sponges (Porifera) represent the evolutionary oldest metazoan phylum still extant today. They have developed a complex Bauplan, based on the existence of structural and regulatory molecules; many of these have been cloned and analyzed in the past years. The demosponge Suberites domuncula has been used as a suitable model to demonstrate that these animals not only possess an adaptive immune response on the level of cytokines, but also, as pointed out here, on the level of synthesis of bioactive alkyl-lipid derivatives. From specimens of S. domuncula the two lyso-PAF (platelet-activating factor) compounds, 1-O-hexadecyl-sn-glycero-3-phosphocholine and 1-O-octadecyl-sn-glycero-3-phosphocholine, have been identified and characterized. These two lyso-PAFs showed pronounced anti-bacterial activity. In the central part of this paper it is shown that the level of synthesis of the lyso-PAF congeners increased in response to the model compound, the endotoxin lipopolysaccharide (LPS). Treatment of the tissue with LPS for 72 h substantially increased the synthesis. In order to prove that the lyso-PAFs are really synthesized by the sponge, the key enzyme of the alkyl-dihydroxyacetonephosphate pathway, i.e. alkyl-dihydroxyacetonephosphate synthase (ADS), was cloned from S. domuncula. This sponge enzyme comprises the characteristic features of metazoan ADS enzymes; it is increasingly expressed in the tissue and in the in vitro cell culture system after exposure to LPS. These data are taken as a strong indication that bioactive, low-molecular weight, non-proteinaceous lipid derivatives function in an adaptive manner in response to the endotoxin.Communicated by R. Cattaneo-Vietti, Genova     

New methods for fast on-site measurement of odorous compounds

New methods for measurement of odorous gases, especially for aerosol-bound chemical compounds, have been developed in the Department of Measurement Technology (Technical University of Hamburg Harburg--MT-TUHH). Odorous compounds in the waste gases produced by the food industry were analysed based on high-volume aerosol sampling techniques, enrichment on solid phase micro extraction (SPE) cartridges and analytical measurement techniques using thermal desorption gas chromatography-mass spectrometry. The analysis results were compared to classic analytical procedures using adsorbence materials (Tenax) for enrichment. In comparison to aerosol sampling, analysis of Tenax samples was found to be ineffective, especially for analyzing polar semi volatile compounds. In addition, sensor arrays were also used in the study to characterize odors of different waste gases emitted by food production facilities. Measuring the odor units of the waste gas of a fat producing factory, the results of sensor-array-measurements show good correlation with results obtained with olfactometric measurements.