TY - JOUR A1 - Fussmann, Gregor F. A1 - Weithoff, Guntram A1 - Yoshida, Takehito T1 - A direct, experimental test of resource versus consumer dependence : reply Y1 - 2007 UR - http://esapubs.org/esapubs/journals/ecology.htm U6 - https://doi.org/10.1890/06-1692 SN - 0012-9658 ER - TY - JOUR A1 - Fussmann, Gregor F. A1 - Weithoff, Guntram A1 - Yoshida, Takehito T1 - A direct, experimental test of resource vs. consumer dependence N2 - The uptake of resources from the environment is a vital process for all organisms. Many experimental studies have revealed that the rate at which this process occurs depends critically on the resource concentration, a relationship called "functional response." However, whether the concentration of the consumer normally affects the functional response has been the subject of a long-standing, predominantly theoretical, debate in ecology. Here we present an experimental test between the alternative hypotheses that food uptake depends either only on the resource concentration or on both the resource and the consumer concentrations. In short-term laboratory experiments, we measured the uptake of radioactively labeled, unicellular green algae (Monoraphidium minutum, resource) by the rotifer Brachionus calyciflorus (a consumer) for varying combinations of resource and consumer concentrations. We found that the food uptake by Brachionus depended on the algal concentration with the relationship best described by a Holling type 3 functional response. We detected significant consumer effects on the functional response only at an extraordinarily high Brachionus density (similar to 125 rotifers/mL), which by far exceeds concentrations normally encountered in the field. We conclude that con sumer-dependent food uptake by planktonic rotifers is a phenomenon that can occur under extreme conditions, but probably plays a minor role in natural environments Y1 - 2005 ER - TY - JOUR A1 - Trindade, Inês T1 - A drop of immunity JF - Molecular plant Y1 - 2021 U6 - https://doi.org/10.1016/j.molp.2021.07.022 SN - 1674-2052 SN - 1752-9867 VL - 14 IS - 9 SP - 1437 EP - 1438 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Demal, Till Joscha A1 - Heise, Melina A1 - Reiz, Benedikt A1 - Dogra, Deepika A1 - Braenne, Ingrid A1 - Reichenspurner, Hermann A1 - Männer, Jörg A1 - Aherrahrou, Zouhair A1 - Schunkert, Heribert A1 - Erdmann, Jeanette A1 - Abdelilah-Seyfried, Salim T1 - A familial congenital heart disease with a possible multigenic origin involving a mutation in BMPR1A JF - Scientific reports N2 - The genetics of many congenital heart diseases (CHDs) can only unsatisfactorily be explained by known chromosomal or Mendelian syndromes. Here, we present sequencing data of a family with a potentially multigenic origin of CHD. Twelve of nineteen family members carry a familial mutation [NM_004329.2:c.1328 G > A (p.R443H)] which encodes a predicted deleterious variant of BMPR1A. This mutation co-segregates with a linkage region on chromosome 1 that associates with the emergence of severe CHDs including Ebstein’s anomaly, atrioventricular septal defect, and others. We show that the continuous overexpression of the zebrafish homologous mutation bmpr1aap.R438H within endocardium causes a reduced AV valve area, a downregulation of Wnt/ß-catenin signalling at the AV canal, and growth of additional tissue mass in adult zebrafish hearts. This finding opens the possibility of testing genetic interactions between BMPR1A and other candidate genes within linkage region 1 which may provide a first step towards unravelling more complex genetic patterns in cardiovascular disease aetiology. Y1 - 2019 U6 - https://doi.org/10.1038/s41598-019-39648-7 SN - 2045-2322 VL - 9 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Xiao, Shangbin A1 - Liu, Liu A1 - Wang, Wei A1 - Lorke, Andreas A1 - Woodhouse, Jason Nicholas A1 - Grossart, Hans-Peter T1 - A Fast-Response Automated Gas Equilibrator (FaRAGE) for continuous in situ measurement of CH4 and CO2 dissolved in water JF - Hydrology and earth system sciences : HESS N2 - Biogenic greenhouse gas emissions, e.g., of methane (CH4) and carbon dioxide (CO2) from inland waters, contribute substantially to global warming. In aquatic systems, dissolved greenhouse gases are highly heterogeneous in both space and time. To better understand the biological and physical processes that affect sources and sinks of both CH4 and CO2, their dissolved concentrations need to be measured with high spatial and temporal resolution. To achieve this goal, we developed the Fast-Response Automated Gas Equilibrator (FaRAGE) for real-time in situ measurement of dissolved CH4 and CO2 concentrations at the water surface and in the water column. FaRAGE can achieve an exceptionally short response time (t(95%) = 12 s when including the response time of the gas analyzer) while retaining an equilibration ratio of 62.6% and a measurement accuracy of 0.5% for CH4. A similar performance was observed for dissolved CO2 (t(95%) = 10 s, equilibration ratio 67.1 %). An equilibration ratio as high as 91.8% can be reached at the cost of a slightly increased response time (16 s). The FaRAGE is capable of continuously measuring dissolved CO2 and CH4 concentrations in the nM-to-submM (10(-9)-10(-3) mol L-1) range with a detection limit of subnM (10(-10) mol L-1), when coupling with a cavity ring-down greenhouse gas analyzer (Picarro GasScouter). FaRAGE allows for the possibility of mapping dissolved concentration in a "quasi" three-dimensional manner in lakes and provides an inexpensive alternative to other commercial gas equilibrators. It is simple to operate and suitable for continuous monitoring with a strong tolerance for suspended particles. While the FaRAGE is developed for inland waters, it can be also applied to ocean waters by tuning the gas-water mixing ratio. The FaRAGE is easily adapted to suit other gas analyzers expanding the range of potential applications, including nitrous oxide and isotopic composition of the gases. Y1 - 2020 U6 - https://doi.org/10.5194/hess-24-3871-2020 SN - 1027-5606 SN - 1607-7938 VL - 24 IS - 7 SP - 3871 EP - 3880 PB - European Geosciences Union (EGU) ; Copernicus CY - Munich ER - TY - JOUR A1 - Brothers, Soren M. A1 - Koehler, J. A1 - Attermeyer, Katrin A1 - Grossart, Hans-Peter A1 - Mehner, T. A1 - Meyer, N. A1 - Scharnweber, Inga Kristin A1 - Hilt, Sabine T1 - A feedback loop links brownification and anoxia in a temperate, shallow lake JF - Limnology and oceanography N2 - This study examines a natural, rapid, fivefold increase in dissolved organic carbon (DOC) concentrations in a temperate shallow lake, describing the processes by which increased DOC resulted in anoxic conditions and altered existing carbon cycling pathways. High precipitation for two consecutive years led to rising water levels and the flooding of adjacent degraded peatlands. Leaching from the flooded soils provided an initial increase in DOC concentrations (from a 2010 mean of 12 +/- 1 mg L-1 to a maximum concentration of 53 mg L-1 by June 2012). Increasing water levels, DOC, and phytoplankton concentrations reduced light reaching the sediment surface, eliminating most benthic primary production and promoting anoxia in the hypolimnion. From January to June 2012 there was a sudden increase in total phosphorus (from 57 mg L-1 to 216 mg L-1), DOC (from 24.6 mg L-1 to 53 mg L-1), and iron (from 0.12 mg L-1 to 1.07 mg L-1) concentrations, without any further large fluxes in water levels. We suggest that anoxic conditions at the sediment surface and flooded soils produced a dramatic release of these chemicals that exacerbated brownification and eutrophication, creating anoxic conditions that persisted roughly 6 months below a water depth of 1 m and extended periodically to the water surface. This brownification-anoxia feedback loop resulted in a near-complete loss of macroinvertebrate and fish populations, and increased surface carbon dioxide (CO2) emissions by an order of magnitude relative to previous years. Y1 - 2014 U6 - https://doi.org/10.4319/lo.2014.59.4.1388 SN - 0024-3590 SN - 1939-5590 VL - 59 IS - 4 SP - 1388 EP - 1398 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Röthlein, Christoph A1 - Miettinen, Markus S. A1 - Ignatova, Zoya T1 - A flexible approach to assess fluorescence decay functions in complex energy transfer systems JF - BMC biophysics N2 - Background: Time-correlated Forster resonance energy transfer (FRET) probes molecular distances with greater accuracy than intensity-based calculation of FRET efficiency and provides a powerful tool to study biomolecular structure and dynamics. Moreover, time-correlated photon count measurements bear additional information on the variety of donor surroundings allowing more detailed differentiation between distinct structural geometries which are typically inaccessible to general fitting solutions. Results: Here we develop a new approach based on Monte Carlo simulations of time-correlated FRET events to estimate the time-correlated single photon counts (TCSPC) histograms in complex systems. This simulation solution assesses the full statistics of time-correlated photon counts and distance distributions of fluorescently labeled biomolecules. The simulations are consistent with the theoretical predictions of the dye behavior in FRET systems with defined dye distances and measurements of randomly distributed dye solutions. We validate the simulation results using a highly heterogeneous aggregation system and explore the conditions to use this tool in complex systems. Conclusion: This approach is powerful in distinguishing distance distributions in a wide variety of experimental setups, thus providing a versatile tool to accurately distinguish between different structural assemblies in highly complex systems. KW - Time resolved FRET KW - Monte-Carlo simulations KW - Complex heterogeneous systems KW - Protein aggregation Y1 - 2015 U6 - https://doi.org/10.1186/s13628-015-0020-z SN - 2046-1682 VL - 8 PB - BioMed Central CY - London ER - TY - JOUR A1 - Sharma, Neha A1 - Ruelens, Philip A1 - Maggen, Thomas A1 - Dochy, Niklas A1 - Torfs, Sanne A1 - Kaufmann, Kerstin A1 - Rohde, Antje A1 - Geuten, Koen T1 - A Flowering Locus C Homolog Is a Vernalization-Regulated Repressor in Brachypodium and Is Cold Regulated in Wheat JF - Plant physiology : an international journal devoted to physiology, biochemistry, cellular and molecular biology, biophysics and environmental biology of plants N2 - Winter cereals require prolonged cold to transition from vegetative to reproductive development. This process, referred to as vernalization, has been extensively studied in Arabidopsis (Arabidopsis thaliana). In Arabidopsis, a key flowering repressor called FLOWERING LOCUS C (FLC) quantitatively controls the vernalization requirement. By contrast, in cereals, the vernalization response is mainly regulated by the VERNALIZATION genes, VRN1 and VRN2. Here, we characterize ODDSOC2, a recently identified FLC ortholog in monocots, knowing that it belongs to the FLC lineage. By studying its expression in a diverse set of Brachypodium accessions, we find that it is a good predictor of the vernalization requirement. Analyses of transgenics demonstrated that BdODDSOC2 functions as a vernalization-regulated flowering repressor. In most Brachypodium accessions BdODDSOC2 is down-regulated by cold, and in one of the winter accessions in which this down-regulation was evident, BdODDSOC2 responded to cold before BdVRN1. When stably down-regulated, the mechanism is associated with spreading H3K27me3 modifications at the BdODDSOC2 chromatin. Finally, homoeolog-specific gene expression analyses identify TaAGL33 and its splice variant TaAGL22 as the FLC orthologs in wheat (Triticum aestivum) behaving most similar to Brachypodium ODDSOC2. Overall, our study suggests that ODDSOC2 is not only phylogenetically related to FLC in eudicots but also functions as a flowering repressor in the vernalization pathway of Brachypodium and likely other temperate grasses. These insights could prove useful in breeding efforts to refine the vernalization requirement of temperate cereals and adapt varieties to changing climates. Y1 - 2016 U6 - https://doi.org/10.1104/pp.16.01161 SN - 0032-0889 SN - 1532-2548 VL - 173 IS - 2 SP - 1301 EP - 1315 PB - American Society of Plant Physiologists CY - Rockville ER - TY - JOUR A1 - Schlägel, Ulrike E. A1 - Lewis, Mark A. T1 - A framework for analyzing the robustness of movement models to variable step discretization JF - Journal of mathematical biology N2 - When sampling animal movement paths, the frequency at which location measurements are attempted is a critical feature for data analysis. Important quantities derived from raw data, e.g. travel distance or sinuosity, can differ largely based on the temporal resolution of the data. Likewise, when movement models are fitted to data, parameter estimates have been demonstrated to vary with sampling rate. Thus, biological statements derived from such analyses can only be made with respect to the resolution of the underlying data, limiting extrapolation of results and comparison between studies. To address this problem, we investigate whether there are models that are robust against changes in temporal resolution. First, we propose a mathematically rigorous framework, in which we formally define robustness as a model property. We then use the framework for a thorough assessment of a range of basic random walk models, in which we also show how robustness relates to other probabilistic concepts. While we found robustness to be a strong condition met by few models only, we suggest a new method to extend models so as to make them robust. Our framework provides a new systematic, mathematically founded approach to the question if, and how, sampling rate of movement paths affects statistical inference. KW - Animal movement KW - Random walk KW - Sampling rate KW - Discretization KW - GPS data KW - Parameter estimation Y1 - 2016 U6 - https://doi.org/10.1007/s00285-016-0969-5 SN - 0303-6812 SN - 1432-1416 VL - 73 SP - 815 EP - 845 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Mao, Hailiang A1 - Nakamura, Moritaka A1 - Viotti, Corrado A1 - Grebe, Markus T1 - A Framework for Lateral Membrane Trafficking and Polar Tethering of the PEN3 ATP-Binding Cassette Transporter JF - Plant physiology : an international journal devoted to physiology, biochemistry, cellular and molecular biology, biophysics and environmental biology of plants N2 - The outermost cell layer of plants, the epidermis, and its outer (lateral) membrane domain facing the environment are continuously challenged by biotic and abiotic stresses. Therefore, the epidermis and the outer membrane domain provide important selective and protective barriers. However, only a small number of specifically outer membrane-localized proteins are known. Similarly, molecular mechanisms underlying the trafficking and the polar placement of outer membrane domain proteins require further exploration. Here, we demonstrate that ACTIN7 (ACT7) mediates trafficking of the PENETRATION3 (PEN3) outer membrane protein from the trans-Golgi network (TGN) to the plasma membrane in the root epidermis of Arabidopsis (Arabidopsis thaliana) and that actin function contributes to PEN3 endocytic recycling. In contrast to such generic ACT7-dependent trafficking from the TGN, the EXOCYST84b (EXO84b) tethering factor mediates PEN3 outer-membrane polarity. Moreover, precise EXO84b placement at the outer membrane domain itself requires ACT7 function. Hence, our results uncover spatially and mechanistically distinct requirements for ACT7 function during outer lateral membrane cargo trafficking and polarity establishment. They further identify an exocyst tethering complex mediator of outer lateral membrane cargo polarity. Y1 - 2016 U6 - https://doi.org/10.1104/pp.16.01252 SN - 0032-0889 SN - 1532-2548 VL - 172 SP - 2245 EP - 2260 PB - American Society of Plant Physiologists CY - Rockville ER -