TY - JOUR A1 - Hundertmark, Michaela A1 - Dimova, Rumiana A1 - Lengefeld, Jan A1 - Seckler, Robert A1 - Hincha, Dirk K. T1 - The intrinsically disordered late embryogenesis abundant protein LEA18 from Arabidopsis thaliana modulates membrane stability through binding and folding JF - Biochimica et biophysica acta : Biomembranes N2 - Intrinsically disordered proteins (IDPs) constitute a substantial part of cellular proteomes. late embryogenesis abundant (LEA) proteins are mostly predicted to be IDPs associated with dehydration tolerance in many plant, animal and bacterial species. Their functions, however, are largely unexplored and also their structure and interactions with potential target molecules have only recently been experimentally investigated in a small number of proteins. Here, we report on the structure and interactions with membranes of the Pfam LEA_1 protein LEA18 from the higher plant Arabidopsis thaliana. This functionally uncharacterized positively charged protein specifically aggregated and destabilized negatively charged liposomes. Isothermal titration calorimetry showed binding of the protein to both charged and uncharged membranes. LEA18 alone was largely unstructured in solution. While uncharged membranes had no influence on the secondary structure of LEA18, the protein partially folded into beta-sheet structure in the presence of negatively charged liposomes. These data suggest that LEA18 does not function as a membrane stabilizing protein, as suggested for other LEA proteins. Instead, a possible function of LEA18 could be the composition-dependent modulation of membrane stability, e.g., during signaling or vesicle-mediated transport. KW - Intrinsically disordered protein KW - Late embryogenesis abundant protein KW - Membrane stability KW - Protein-membrane interaction KW - Protein folding Y1 - 2011 U6 - https://doi.org/10.1016/j.bbamem.2010.09.010 SN - 0005-2736 VL - 1808 IS - 1 SP - 446 EP - 453 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Wischerhoff, Erik A1 - Badi, Nezha A1 - Laschewsky, André A1 - Lutz, Jean-Francois ED - Börner, Hans Gerhard ED - Lutz, JF T1 - Smart polymer surfaces concepts and applications in biosciences JF - Advances in polymer science = Fortschritte der Hochpolymeren-Forschung JF - Advances in Polymer Science N2 - Stimuli-responsive macromolecules (i.e., pH-, thermo-, photo-, chemo-, and bioresponsive polymers) have gained exponential importance in materials science, nanotechnology, and biotechnology during the last two decades. This chapter describes the usefulness of this class of polymer for preparing smart surfaces (e.g., modified planar surfaces, particles surfaces, and surfaces of three-dimensional scaffolds). Some efficient pathways for connecting these macromolecules to inorganic, polymer, or biological substrates are described. In addition, some emerging bioapplications of smart polymer surfaces (e.g., antifouling surfaces, cell engineering, protein chromatography, tissue engineering, biochips, and bioassays) are critically discussed. KW - Antifouling surfaces KW - Bioactive surfaces KW - Biocompatible polymers KW - Bioseparation KW - Cell engineering KW - Polymer-modified surfaces KW - Stimuli-responsive polymers Y1 - 2011 SN - 978-3-642-20154-7 U6 - https://doi.org/10.1007/12_2010_88 SN - 0065-3195 VL - 240 IS - 1 SP - 1 EP - 33 PB - Springer CY - Berlin ER - TY - JOUR A1 - Wels, Volkhard T1 - The poetics as part of aristotle's organon JF - Beiträge zur Geschichte der deutschen Sprache und Literatur Y1 - 2011 SN - 0005-8076 VL - 133 IS - 3-4 SP - 470 EP - 486 PB - Niemeyer CY - Tübingen ER - TY - JOUR A1 - Wels, Volkhard T1 - Poetry as reasoning technique an interpretation of the Aristotelian averroes processing "Poetics" in its Latin transfers JF - Beiträge zur Geschichte der deutschen Sprache und Literatur Y1 - 2011 SN - 0005-8076 VL - 133 IS - 2 SP - 265 EP - 289 PB - Niemeyer CY - Tübingen ER - TY - JOUR A1 - Binzer, Amrei A1 - Brose, Ulrich A1 - Curtsdotter, Alva A1 - Ekloef, Anna A1 - Rall, Bjoern C. A1 - Riede, Jens O. A1 - de Castro, Francisco T1 - The susceptibility of species to extinctions in model communities JF - Basic and applied ecology : Journal of the Gesellschaft für Ökologie N2 - Despite the fact that the loss of a species from a community has the potential to cause a dramatic decline in biodiversity, for example through cascades of secondary extinctions, little is known about the factors contributing to the extinction risk of any particular species. Here we expand earlier modeling approaches using a dynamic food-web model that accounts for bottom-up as well as top-down effects. We investigate what factors influence a species' extinction risk and time to extinction of the non-persistent species. We identified three basic properties that affect a species' risk of extinction. The highest extinction risk is born by species with (1) low energy input (e.g. high trophic level), (2) susceptibility to the loss of energy pathways (e.g. specialists with few prey species) and (3) dynamic instability (e.g. low Hill exponent and reliance on homogeneous energy channels when feeding on similarly sized prey). Interestingly, and different from field studies, we found that the trophic level and not the body mass of a species influences its extinction risk. On the other hand, body mass is the single most important factor determining the time to extinction of a species, resulting in small species dying first. This suggests that in the field the trophic level might have more influence on the extinction risk than presently recognized. KW - Extinction risk KW - Allometry KW - Dynamic modeling Y1 - 2011 U6 - https://doi.org/10.1016/j.baae.2011.09.002 SN - 1439-1791 VL - 12 IS - 7 SP - 590 EP - 599 PB - Elsevier CY - Jena ER - TY - JOUR A1 - Riede, Jens O. A1 - Binzer, Amrei A1 - Brose, Ulrich A1 - de Castro, Francisco A1 - Curtsdotter, Alva A1 - Rall, Bjoern C. A1 - Ekloef, Anna T1 - Size-based food web characteristics govern the response to species extinctions JF - Basic and applied ecology : Journal of the Gesellschaft für Ökologie N2 - How ecological communities react to species extinctions is a long-standing yet current question in ecology. The species constituting the basic units of ecosystems interact with each other forming complex networks of trophic relationships and the characteristics of these networks are highly important for the consequences of species extinction. Here we take a more general approach and analyze a broad range of network characteristics and their role in determining food web susceptibility to secondary extinctions. We extend previous studies, that have focused on the consequences of topological and dynamical food web parameters for food web robustness, by also defining network-wide characteristics depending on the relationships between the distribution of species body masses and other species characteristics. We use a bioenergetic dynamical model to simulate realistically structured model food webs that differ in their structural and dynamical properties as well as their size structure. In order to measure food web robustness we calculated the proportion of species going secondarily extinct. A multiple regression analysis was then used to fit a general model relating the proportion of species going secondarily extinct to the measured food web properties. Our results show that there are multiple factors from all three groups of food web characteristics that affect food web robustness. However, we find the most striking effect was related to the body mass abundance relationship which points to the importance of body mass relationships for food web stability. KW - Body mass-abundance KW - Connectance KW - Food web robustness KW - Hill exponent KW - Size structure KW - Secondary extinctions Y1 - 2011 U6 - https://doi.org/10.1016/j.baae.2011.09.006 SN - 1439-1791 VL - 12 IS - 7 SP - 581 EP - 589 PB - Elsevier CY - Jena ER - TY - JOUR A1 - Curtsdotter, Alva A1 - Binzer, Amrei A1 - Brose, Ulrich A1 - de Castro, Francisco A1 - Ebenman, Bo A1 - Ekloef, Anna A1 - Riede, Jens O. A1 - Thierry, Aaron A1 - Rall, Bjoern C. T1 - Robustness to secondary extinctions comparing trait-based sequential deletions in static and dynamic food webs JF - Basic and applied ecology : Journal of the Gesellschaft für Ökologie N2 - The loss of species from ecological communities can unleash a cascade of secondary extinctions, the risk and extent of which are likely to depend on the traits of the species that are lost from the community. To identify species traits that have the greatest impact on food web robustness to species loss we here subject allometrically scaled, dynamical food web models to several deletion sequences based on species' connectivity, generality, vulnerability or body mass. Further, to evaluate the relative importance of dynamical to topological effects we compare robustness between dynamical and purely topological models. This comparison reveals that the topological approach overestimates robustness in general and for certain sequences in particular. Top-down directed sequences have no or very low impact on robustness in topological analyses, while the dynamical analysis reveals that they may be as important as high-impact bottom-up directed sequences. Moreover, there are no deletion sequences that result, on average, in no or very few secondary extinctions in the dynamical approach. Instead, the least detrimental sequence in the dynamical approach yields an average robustness similar to the most detrimental (non-basal) deletion sequence in the topological approach. Hence, a topological analysis may lead to erroneous conclusions concerning both the relative and the absolute importance of different species traits for robustness. The dynamical sequential deletion analysis shows that food webs are least robust to the loss of species that have many trophic links or that occupy low trophic levels. In contrast to previous studies we can infer, albeit indirectly, that secondary extinctions were triggered by both bottom-up and top-down cascades. KW - Species loss KW - Extinction cascades KW - Top-down effect KW - Bottom-up effect KW - Stability KW - Body size KW - Trophic interactions KW - Vulnerability KW - Generality KW - Keystone species Y1 - 2011 U6 - https://doi.org/10.1016/j.baae.2011.09.008 SN - 1439-1791 VL - 12 IS - 7 SP - 571 EP - 580 PB - Elsevier CY - Jena ER - TY - JOUR A1 - Kloss, Lena A1 - Fischer, Markus A1 - Durka, Walter T1 - Land-use effects on genetic structure of a common grassland herb a matter of scale JF - Basic and applied ecology : Journal of the Gesellschaft für Ökologie N2 - The most common management practices in European grasslands are grazing by livestock and mowing for silage and hay. Grazing and mowing differ in their potential effects on plant gene flow and resulting population genetic structure. After assessing its breeding system, we investigated the effect of land use on the population genetic structure in the common grassland plant Veronica chamaedrys using 63 study populations on meadows, mown pastures and pastures in three regions in Germany, the so-called Biodiversity Exploratories. We determined plant density and analysed the genetic diversity, differentiation and small-scale genetic structure using amplified fragment length polymorphism (AFLP) markers. The breeding system of V chamaedrys turned out as self-incompatible and outcrossing. Its genetic diversity did not differ among land-use types. This may be attributed to large population sizes and the strong dispersal ability of the species, which maintains genetically diverse populations not prone to genetic drift. Genetic differentiation among populations was low (overall F(ST) = 0.075) but significant among the three regions. Land use had only weak effects on population differentiation in only one region. However, land use affected small-scale genetic structure suggesting that gene flow within plots was more restricted on meadows than on mown and unmown pastures. Our study shows that land use influences genetic structure mainly at the small scale within populations, despite high gene flow. KW - Biodiversity exploratories KW - Mowing KW - Grazing KW - AFLP KW - Veronica KW - Breeding system KW - Pollination experiment KW - Pollen-ovule ratio KW - Isolation by distance KW - Spatial autocorrelation Y1 - 2011 U6 - https://doi.org/10.1016/j.baae.2011.06.001 SN - 1439-1791 VL - 12 IS - 5 SP - 440 EP - 448 PB - Elsevier CY - Jena ER - TY - JOUR A1 - Raabova, Jana A1 - Muenzbergova, Zuzana A1 - Fischer, Markus T1 - The role of spatial scale and soil for local adaptation in Inula hirta JF - Basic and applied ecology : Journal of the Gesellschaft für Ökologie N2 - Many plant populations are adapted to their local environment. Reciprocal transplant experiments in the field and in the experimental garden allow for studying different aspects of local adaptation. However, usually only one of these approaches is used. We applied both experimental approaches to study the role of spatial scale and soil conditions for local adaptation in the perennial herb Inula hirta. We reciprocally sowed seeds and transplanted juvenile plants among six field sites from two regions and, in the garden, among pots with soil from each field site. We recorded germination percentage, survival percentage, number of stems and plant height in all experiments. We also recorded above- and below-ground biomass, flowering percentage and the number of flower heads in the garden. No population-specific local adaptation was detected in germination, survival, flowering percentages or in the number of flower heads. At the regional scale in the field, however, the performance of local transplants was higher than the performance of foreign transplants by 10% and 7% in the two regions, respectively. Similarly, when grown in the garden in soil from the more basic and nutrient-poorer region, plant height and aboveground biomass of local transplants were higher than the corresponding values for foreign transplants by 31% and 112%, respectively. Congruent evidence for local adaptation from the juvenile-transplant experiments in field and garden suggests that soil conditions represent an important factor of local adaptation in I. hirta. Overall, our results show that both spatial scale and soil conditions play an important role for local adaptation in I. hirta. Moreover, we underline the importance of combining field and garden experiments to reveal factors affecting local adaptation in plants. KW - Dry grasslands KW - Fitness components KW - Genotype by environment KW - Habitat fragmentation KW - Home-site advantage KW - Natural selection KW - Plant traits KW - Reciprocal transplant Y1 - 2011 U6 - https://doi.org/10.1016/j.baae.2011.01.001 SN - 1439-1791 VL - 12 IS - 2 SP - 152 EP - 160 PB - Elsevier CY - Jena ER - TY - JOUR A1 - Klein, Markus A1 - Rosenberger, Elke T1 - Asymptotic eigenfunctions for a class of difference operators JF - Asymptotic analysis N2 - We analyze a general class of difference operators H(epsilon) = T(epsilon) + V(epsilon) on l(2)((epsilon Z)(d)), where V(epsilon) is a one-well potential and epsilon is a small parameter. We construct formal asymptotic expansions of WKB-type for eigenfunctions associated with the low lying eigenvalues of H(epsilon). These are obtained from eigenfunctions or quasimodes for the operator H(epsilon), acting on L(2)(R(d)), via restriction to the lattice (epsilon Z)(d). KW - difference operator KW - tunneling KW - WKB-expansion KW - quasimodes Y1 - 2011 U6 - https://doi.org/10.3233/ASY-2010-1025 SN - 0921-7134 VL - 73 IS - 1-2 SP - 1 EP - 36 PB - IOS Press CY - Amsterdam ER -