Beeinflussung des Eingeweidesitus beim Alpenmolch (Triturus alpestris) durch elektrischen Strom

Zusammenfassung Neurula-Keime (Harrison-Stadien 15–17) vom Alpenmolch wurden in einem Elektrophoresegerät 1 Std lang der Wirkung eines elektrischen Stromes ausgesetzt. Unter den im Larvenstadium fixierten Versuchstieren fanden sich Eingeweide-Irreguläre und -Inverse in einem gegenüber Kontrollen stark erhöhten, statistisch gesicherten Prozentsatz.

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Influence of the electrical current upon the situs viscerum of triturus alpestris

Summary Neurulae (Harrison 15–17) ofTriturus alpestris were kept within an electrical set up for 1 hour. At a later stage the larvae showed irregularities and inversions of their viscera in a much higher frequency than the untreated controls.

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Durchgeführt im Rahmen des Forschungsvertrages 041-65-10 BIO D mit Euratom. Mit Unterstützung der Deutschen Forschungsgemeinschaft durch Leihapparate im Heiligenberg-Institut.     

Regional diversity,population trends and threat assessment of the weeds of traditional agriculture in Greece

On the basis of extensive field studies throughout Greece and of about 19 500 field and literature records extracted from the Flora Hellenica Database, we provide the first survey of wild plant species of traditional agriculture in Greece (hereafter TA species). For each of the 138 taxa, life form, rareness (on national scale), local abundance (habitat occupancy) and regional restrictedness are given. We infer population trends from the record chronology of the taxa in the Flora Hellenica Database, and we assess the Red List status of the arable plants using IUCN criteria. According to current knowledge, two TA species are presumed Extinct in Greece and seven Critically Endangered. Almost half of the species are threatened, including 46 Vulnerable and 15 Endangered taxa. There is a high proportion of locally distributed taxa among Greek TA species. Distribution patterns show a pronounced south–north gradient, and the unique character of the East Aegean arable flora is revealed. Most arable species are annuals (83%). Perennial herbs, mostly bulbous or tuberous plants (geophytes), account for 17%, and a major proportion of the latter must be considered as threatened at different levels. The chronology of decline of certain TA species is reflected by processes of agricultural intensification and regional urbanization. We suggest conservation measures for the unique arable flora of Greece. To reflect the geographical and ecoregional variation, in situ measures should focus on areas with species‐rich arable fields in all phytogeographical regions of Greece. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 175 , 607–623.     

Thermodynamic rules for the design of high affinity HIV-1 protease inhibitors with adaptability to mutations and high selectivity towards unwanted targets

Protease inhibitors are key components in the chemotherapy of HIV-1 infection. However, the long term efficacy of antiretroviral therapies is hampered by issues of patient compliance often associated with the presence of severe side effects, and above all by the appearance of drug resistance. The development of new protease inhibitors with high potency, low susceptibility to mutations and minimal affinity for unwanted targets is an urgent goal. The engineering of these adaptive inhibitors requires identification of the critical determinants of affinity, adaptability, and selectivity. Analysis of the binding database for existing clinical and experimental inhibitors has allowed us to address the following questions in a quantitative fashion: (1) Is there an optimal binding affinity? Or, are the highest affinity inhibitors necessarily the best inhibitors? (2) What is the dependence of optimal affinity on adaptability and selectivity? (3) What are the determinants of adaptability to mutations associated with drug resistance? (4) How selectivity against unwanted targets can be improved? It is shown that the optimal affinity is a function of the effective target concentration and the desired adaptability and selectivity factors. Furthermore, knowledge of the enthalpic and entropic contributions to the binding affinity to the wild type provides a way of anticipating the response of an inhibitor to mutations associated with drug resistance, and therefore, a valuable guideline for optimization.     

Phylogenetic analysis of sexual systems in Inuleae (Asteraceae)

From an ancestor with bisexual flowers, plants with unisexual flowers, or even unisexual individuals have evolved in different lineages of angiosperms. The Asteraceae tribe Inuleae includes hermaphroditic, monoecious, dioecious, and gynomonoecious species. Gynomonoecy, the sexual system in which female and bisexual flowers occur on the same plant, is prevalent in the Asteraceae. We inferred one large gene phylogeny (ndhF) and two supertrees to investigate whether gynomonoecy was a stage in the evolution from hermaphroditism to monoecy. We identified transitions in sexual system evolution using the stochastic character mapping method. From gynomonoecious ancestors, both hermaphroditic and monoecious descendants have evolved. Gynomonoecy was not restricted to a stage in the evolution toward monoecy because the number of transitions and the rate of change from monoecy to gynomonoecy were much higher than the opposite. We also investigated one hypothesized association among female flowers and the development of a petaloid ray as an explanation of gynomonoecy maintenance in Asteraceae. We found that peripheral female flowers and petaloid rays were phylogenetically correlated. However, empirical evidence shows that a causal relationship between these traits is not clear.     

Invasion success depends on invader body size in a size-structured mixed predation–competition community

1.  The size of an individual is an important determinant of its trophic position and the type of interactions it engages in with other heterospecific and conspecific individuals. Consequently an individual's ecological role in a community changes with its body size over ontogeny, leading to that trophic interactions between individuals are a size-dependent and ontogenetically variable mixture of competition and predation.
2.  Because differently sized individuals thus experience different biotic environments, invasion success may be determined by the body size of the invaders. Invasion outcome may also depend on the productivity of the system as productivity influences the biotic environment.
3.  In a laboratory experiment with two poeciliid fishes the body size of the invading individuals and the daily amount of food supplied were manipulated.
4.  Large invaders established persistent populations and drove the resident population to extinction in 10 out of 12 cases, while small invaders failed in 10 out of 12 trials. Stable coexistence was virtually absent. Invasion outcome was independent of productivity.
5.  Further analyses suggest that small invaders experienced a competitive recruitment bottleneck imposed on them by the resident population. In contrast, large invaders preyed on the juveniles of the resident population. This predation allowed the large invaders to establish successfully by decreasing the resident population densities and thus breaking the bottleneck.
6.  The results strongly suggest that the size distribution of invaders affects their ability to invade, an implication so far neglected in life-history omnivory systems. The findings are further in agreement with predictions of life-history omnivory theory, that size-structured interactions demote coexistence along a productivity gradient.