Differences in osmotolerance in freshwater and brackish water populations of Theodoxus fluviatilis (Gastropoda: Neritidae) are associated with differential protein expression

The euryhaline gastropod Theodoxus fluviatilis is found in northern Germany in freshwater or in brackish water habitats in the Baltic Sea. Previous studies have revealed that individuals from both habitats are not distinguishable by morphological characters or by sequence comparison of DNA encoding 16S RNA or cytochrome C. As reported in this study, animals collected in the two habitats differ substantially in their physiological ability to adapt to different salinities. Comparison of accumulation rates of ninhydrin-positive substances (NPS) in foot muscle upon transfer of animals to higher medium salinities revealed that brackish water animals were perfectly able to mobilize NPS, while freshwater animals had only limited ability to do so. In an attempt to explore whether this difference in physiology may be caused by genetic differentiation, we compared protein expression patterns of soluble foot muscle proteins using 2D gel electrophoresis and silver staining. Of the 40 consistently detected protein spots, 27 showed similar levels in protein expression in animals collected from freshwater or brackish water habitats, respectively. In 12 spots, however, protein concentration was higher in brackish water than in freshwater animals. In four of these spots, expression levels followed increases or decreases in medium salinities. In a different set of 4 of these 12 spots, protein levels were always higher in brackish water as compared to freshwater animals, regardless of their physiological situation (14 days in artificial pond water or in medium with a salinity of 16‰). The remaining 4 of the 12 spots had complex expression patterns. Protein levels of the remaining single spot were generally higher in freshwater animals than in brackish water animals. These expression patterns may indicate that freshwater and brackish water animals of T. fluviatilis belong to different locally adapted populations with subtle genetic differentiation

An Anatomy of Hazard Systems and its Application to Acute Process Hazards

The paper proposes a generalized model of hazard systems. It seeks to demonstrate the underlying commonality of the elements and structures which make up hazard systems, and to render explicit certain concepts which are implicit in earlier models.The model comprises a source with a potential to emit harmful energy or matter or some combination of the two, and one or more receptors which may be affected by such harmful emissions. It takes account of the fact that an inanimate receptor may itself, on absorbing energy, then become a source.Except where the source and the receptor are in direct contact, the model provides for one or more successive transmission paths which are carriers of the harmful emission from source to receptor(s). It also provides for the presence of barriers. The emission, which may be quantified at any point in the system by the integral of its flux (intensity) with respect to time, may be attenuated by the transmitting medium, and/or by barriers. This, after taking account of the relevant impact area of the receptor (typically the projected area), yields the dose incident upon the receptor(s). The prediction of harm from this dose requires the incorporation of a transform, denoted in the paper by TD → H, which cannot be expressed in purely physical terms but which is derived from observation or from experiment. This provides a probabilistic relationship between the level of incident dose and the level of harm inflicted.The paper subjects the purely physical elements of such hazard systems to dimensional analysis. It demonstrates how, in some cases, emissions are quantified in practice by indices with dimensions which differ from those of an integral of a flux with time.Though the model is conceived as a perfectly general one which is not limited by the nature of the hazard or by the time-scale of the events, the authors claim that it can be applied with particular relevance to the potentially harmful acute emissions of energy or of matter, or of both in combination, which occur from time to time in the process industries.Based upon the above concepts, and using existing methodologies for the estimation of the frequency with which the potential of a source may be realized, algorithms are proposed for calculating individual risk and its derivative, societal risk

Studien in der Pyridinreihe, ein Beitrag zur Configuration der Aconitsäure

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