@article{KnoxBrownRindfleischGuentheretal.2020, author = {Knox-Brown, Patrick and Rindfleisch, Tobias and G{\"u}nther, Anne and Balow, Kim and Bremer, Anne and Walther, Dirk and Miettinen, Markus S. and Hincha, Dirk K. and Thalhammer, Anja}, title = {Similar Yet Different}, series = {International Journal of Molecular Sciences}, volume = {21}, journal = {International Journal of Molecular Sciences}, number = {8}, publisher = {Molecular Diversity Preservation International}, address = {Basel}, issn = {1422-0067}, doi = {10.3390/ijms21082794}, pages = {25}, year = {2020}, abstract = {The importance of intrinsically disordered late embryogenesis abundant (LEA) proteins in the tolerance to abiotic stresses involving cellular dehydration is undisputed. While structural transitions of LEA proteins in response to changes in water availability are commonly observed and several molecular functions have been suggested, a systematic, comprehensive and comparative study of possible underlying sequence-structure-function relationships is still lacking. We performed molecular dynamics (MD) simulations as well as spectroscopic and light scattering experiments to characterize six members of two distinct, lowly homologous clades of LEA_4 family proteins from Arabidopsis thaliana. We compared structural and functional characteristics to elucidate to what degree structure and function are encoded in LEA protein sequences and complemented these findings with physicochemical properties identified in a systematic bioinformatics study of the entire Arabidopsis thaliana LEA_4 family. Our results demonstrate that although the six experimentally characterized LEA_4 proteins have similar structural and functional characteristics, differences concerning their folding propensity and membrane stabilization capacity during a freeze/thaw cycle are obvious. These differences cannot be easily attributed to sequence conservation, simple physicochemical characteristics or the abundance of sequence motifs. Moreover, the folding propensity does not appear to be correlated with membrane stabilization capacity. Therefore, the refinement of LEA_4 structural and functional properties is likely encoded in specific patterns of their physicochemical characteristics.}, language = {en} } @article{SinghDaniSharmaetal.2006, author = {Singh, Jasbir and Dani, Harinder M. and Sharma, Reeta and Steinberg, Pablo}, title = {Inhibition of the biosynthesis of SRP polypeptides and secretory proteins by aflatoxin B-1 can disrupt protein targeting}, series = {Cell biochemistry and function}, volume = {24}, journal = {Cell biochemistry and function}, publisher = {Wiley}, address = {Chichester}, issn = {0263-6484}, doi = {10.1027/cbf.1285}, pages = {507 -- 510}, year = {2006}, abstract = {Cell culture and western blotting studies revealed that aflatoxin B-1 (AFB(1)) inhibits the biosynthesis of two of the constituent polypeptides of signal recognition particle (SRP) (SRP54 and 72). SRP escorts polyribosomes carrying signal peptides from free form in the cytosol to the bound form on endoplasmic reticulum (ER) membrane during protein targeting. These effects of AFB(1) on SRP biosynthesis may inhibit the formation of functional SRP Our experiments have further shown that AFB(1) also inhibits the biosynthesis/translocation of a secretory protein, preprolactin, which fails to appear in the lumen of ER consequent to the treatment with this hepatocarcinogen. The results of the experiments presented in this article therefore enable us to infer for the first time that aflatoxin B-1 may inhibit the functioning of SRP as an escort and deplete the ER of polyribosomes for secretory protein synthesis. As these secretory proteins are important components of the plasma membrane, gap junctions and intercellular matrix, their absence from these locations could disturb cell to cell communication leading to tumorigenesis.}, language = {en} } @article{Oberauer2006, author = {Oberauer, Klaus}, title = {Reasoning with conditionals: A test of formal models of four theories}, series = {Cognitive psychology}, volume = {53}, journal = {Cognitive psychology}, number = {3}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0010-0285}, doi = {10.1016/j.cogpsych.2006.04.001}, pages = {238 -- 283}, year = {2006}, abstract = {The four dominant theories of reasoning from conditionals are translated into formal models: The theory of mental models (Johnson-Laird, P. N., \& Byrne, R. M. J. (2002). Conditionals: a theory of meaning, pragmatics, and inference. Psychological Review, 109, 646-678), the suppositional theory (Evans, J. S. B. T., \& Over, D. E. (2004). If. Oxford: Oxford University Press), a dual-process variant of the model theory (Verschueren, N., Schaeken, W., \& d'Ydewalle, G. (2005). A dual-process specification of causal conditional reasoning. Thinking \& Reasoning, 11, 278-293), and the probabilistic theory (Oaksford, M., Chater, N., \& Larkin, J. (2000). Probabilities and polarity biases in conditional inference. Journal of Experimental Psychology: Learning, Memory, and Cognition, 26, 883-899). The first three theories are formalized as multinomial models. The models are applied to the frequencies of patterns of acceptance or rejection across the four basic inferences modus ponens, acceptance of the consequent, denial of the antecedent, and modus tollens. Model fits are assessed for two large data sets, one representing reasoning with abstract, basic conditionals, the other reflecting reasoning with pseudo-realistic causal and non-causal conditionals. The best account of the data was provided by a modified version of the mental-model theory, augmented by directionality, and by the dual-process model.}, language = {en} } @article{MohsenKindSobolevetal.2006, author = {Mohsen, Ayman and Kind, Rainer and Sobolev, Stephan Vladimir and Weber, Michael}, title = {Thickness of the lithosphere east of the Dead Sea Transform}, series = {Geophysical journal international}, volume = {167}, journal = {Geophysical journal international}, number = {2}, publisher = {Blackwell}, address = {Oxford}, issn = {0956-540X}, doi = {10.1111/j.1365-246X.2006.03185.x}, pages = {845 -- 852}, year = {2006}, abstract = {We use the S receiver function method to study the lithosphere at the Dead Sea Transform (DST). A temporary network of 22 seismic broad-band stations was operated on both sides of the DST from 2000 to 2001 as part of the DESERT project. We also used data from six additional permanent broad-band seismic stations at the DST and in the surrounding area, that is, in Turkey, Saudi Arabia, Egypt and Cyprus. Clear S-to-P converted phases from the crust-mantle boundary (Moho) and a deeper discontinuity, which we interpret as lithosphere-asthenosphere boundary (LAB) have been observed. The Moho depth (30-38 km) obtained from S receiver functions agrees well with the results from P receiver functions and other geophysical data. We observe thinning of the lithosphere on the eastern side of the DST from 80 km in the north of the Dead Sea to about 65 km at the Gulf of Aqaba. On the western side of the DST, the few data indicate a thin LAB of about 65 km. For comparison, we found a 90-km-thick lithosphere in eastern Turkey and a 160-km-thick lithosphere under the Arabian shield, respectively. These observations support previous suggestions, based on xenolith data, heat flow observations, regional uplift history and geodynamic modelling, that the lithosphere around DST has been significantly thinned in the Late Cenozoic, likely following rifting and spreading of the Red Sea.}, language = {en} } @article{GarciaSteinigerReichetal.2006, author = {Garcia, A. L. and Steiniger, J. and Reich, S. C. and Weickert, M. O. and Harsch, I. and Machowetz, A. and Mohlig, M. and Spranger, Joachim and Rudovich, N. N. and Meuser, F. and Doerfer, J. and Katz, N. and Speth, M. and Zunft, Hans-Joachim Franz and Pfeiffer, Andreas F. H. and Koebnick, Corinna}, title = {Arabinoxylan fibre consumption improved glucose metabolism, but did not affect serum adipokines in subjects with impaired glucose tolerance}, series = {Hormone and metabolic research}, volume = {38}, journal = {Hormone and metabolic research}, number = {2}, publisher = {Thieme}, address = {Stuttgart}, issn = {0018-5043}, doi = {10.1055/s-2006-955089}, pages = {761 -- 766}, year = {2006}, abstract = {The consumption of arabinoxylan, a soluble fibre fraction, has been shown to improve glycemic control in type 2 diabetic subjects. Soluble dietary fibre may modulate gastrointestinal or adipose tissue hormones regulating food intake. The present study investigated the effects of arabinoxylan consumption on serum glucose, insulin, lipids, leptin, adiponectin and resistin in subjects with impaired glucose tolerance. In a randomized, single-blind, controlled, crossover intervention trial, 11 adults consumed white bread rolls as either placebo or supplemented with 15g arabinoxylan for 6 weeks with a 6-week washout period. Fasting serum glucose, insulin, triglycerides, unesterified fatty acids, apolipoprotein A1 and B, adiponectin, resistin and leptin were assessed before and after intervention. Fasting serum glucose, serum triglycerides and apolipoprotein A-1 were significantly lower during arabinoxylan consumption compared to placebo (p = 0.029, p = 0.047; p = 0.029, respectively). No effects of arabinoxylan were observed for insulin, adiponectin, leptin and resistin as well as for apolipoprotein B, and unesterified fatty acids. In conclusion, the consumption of AX in subjects with impaired glucose tolerance improved fasting serum glucose, and triglycerides. However, this beneficial effect was not accompanied by changes in fasting adipokine concentrations.}, language = {en} } @article{MaaresKeilKozaetal.2018, author = {Maares, Maria and Keil, Claudia and Koza, Jenny and Straubing, Sophia and Schwerdtle, Tanja and Haase, Hajo}, title = {In Vitro Studies on Zinc Binding and Buffering by Intestinal Mucins}, series = {International Journal of Molecular Sciences}, volume = {19}, journal = {International Journal of Molecular Sciences}, number = {9}, issn = {1422-0067}, doi = {10.3390/ijms19092662}, pages = {20}, year = {2018}, abstract = {The investigation of luminal factors influencing zinc availability and accessibility in the intestine is of great interest when analyzing parameters regulating intestinal zinc resorption. Of note, intestinal mucins were suggested to play a beneficial role in the luminal availability of zinc. Their exact zinc binding properties, however, remain unknown and the impact of these glycoproteins on human intestinal zinc resorption has not been investigated in detail. Thus, the aim of this study is to elucidate the impact of intestinal mucins on luminal uptake of zinc into enterocytes and its transfer into the blood. In the present study, in vitro zinc binding properties of mucins were analyzed using commercially available porcine mucins and secreted mucins of the goblet cell line HT-29-MTX. The molecular zinc binding capacity and average zinc binding affinity of these glycoproteins demonstrates that mucins contain multiple zinc-binding sites with biologically relevant affinity within one mucin molecule. Zinc uptake into the enterocyte cell line Caco-2 was impaired by zinc-depleted mucins. Yet this does not represent their form in the intestinal lumen in vivo under zinc adequate conditions. In fact, zinc-uptake studies into enterocytes in the presence of mucins with differing degree of zinc saturation revealed zinc buffering by these glycoproteins, indicating that mucin-bound zinc is still available for the cells. Finally, the impact of mucins on zinc resorption using three-dimensional cultures was studied comparing the zinc transfer of a Caco-2/HT-29-MTX co-culture and conventional Caco-2 monoculture. Here, the mucin secreting co-cultures yielded higher fractional zinc resorption and elevated zinc transport rates, suggesting that intestinal mucins facilitate the zinc uptake into enterocytes and act as a zinc delivery system for the intestinal epithelium.}, language = {en} } @article{Damaschun2021, author = {Damaschun, Ferdinand}, title = {Christian Gottfried Ehrenberg und die Entwicklung der Mikroskop-Technik im 19. Jahrhundert}, series = {HiN : Alexander von Humboldt im Netz = Christian Gottfried Ehrenberg}, volume = {XXII}, journal = {HiN : Alexander von Humboldt im Netz = Christian Gottfried Ehrenberg}, number = {42}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, issn = {1617-5239}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-515218}, pages = {119 -- 134}, year = {2021}, abstract = {Ab Mitte der 1820er Jahre erfuhr die Mikroskop- Technik eine st{\"u}rmische Entwicklung. Dadurch, dass es gelang, nach und nach die optischen Fehler zu korrigieren, verbesserte sich die Aufl{\"o}sung bis zum Ende des Jahrhunderts um den Faktor 10 von 3 μm auf 0,3 μm. Um 1820 begann Christian Gottfried Ehrenberg mit mikroskopischen Untersuchungen. Er nutzte zun{\"a}chst ein einfaches N{\"u}rnberger Mikroskop. 1832 erwarb er ein Mikroskop aus der Berliner Werkstatt von Pistor \& Schiek, das er dann zeitlebens nutzte. Ein Vergleich der Leistungsf{\"a}higkeit seines Instruments mit der f{\"u}r seine Untersuchungen notwendigen Aufl{\"o}sung zeigt, dass es f{\"u}r seine Untersuchungen vollkommen gen{\"u}gte. F{\"u}r seine Untersuchungsobjekte entwickelte er Pr{\"a}parationstechniken und Aufbewahrungsmethoden f{\"u}r die Dauerpr{\"a}parate. Da er auch die mikroskopischen Abbildungen bis hin zu den Vorlagen f{\"u}r die Kupfertafeln selbst anfertigte, behielt er den gesamten Prozess von der Pr{\"a}paration bis zum Druck der Ergebnisse stets in der Hand.}, language = {de} } @article{Boehme2021, author = {B{\"o}hme, Katrin}, title = {Das große Ganze. Christian Gottfried Ehrenberg und die Gesellschaft Naturforschender Freunde zu Berlin}, series = {HiN : Alexander von Humboldt im Netz = Christian Gottfried Ehrenberg}, volume = {XXII}, journal = {HiN : Alexander von Humboldt im Netz = Christian Gottfried Ehrenberg}, number = {42}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, issn = {1617-5239}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-515226}, pages = {155 -- 169}, year = {2021}, abstract = {Als langj{\"a}hriges und aktives Mitglied der Gesellschaft Naturforschender Freunde zu Berlin bestimmte Ehrenberg ihre Aktivit{\"a}ten und ihr Ansehen maßgeblich mit. Seine Beitr{\"a}ge zu den Sitzungen und Schriften und seine Rolle als Bewohner des gesellschaftseigenen Hauses f{\"o}rderten in der GNF sowohl Fortschritt als auch Best{\"a}ndigkeit. Das Ziel der Naturgeschichte des 18. Jahrhunderts, also die Entdeckung, Beschreibung und Bewahrung m{\"o}glichst aller Organismen- und Gesteinsarten, wurde in der GNF bis in die zweite H{\"a}lfte des 19. Jahrhunderts tradiert. Ehrenbergs wissenschaftliche Leistungen, insbesondere seine zahlreichen Entdeckungen mit Hilfe des Mikroskops, stehen ganz in dieser Tradition.}, language = {de} } @article{NitzeGrosseJonesetal.2018, author = {Nitze, Ingmar and Grosse, Guido and Jones, Benjamin M. and Romanovsky, Vladimir E. and Boike, Julia}, title = {Remote sensing quantifies widespread abundance of permafrost region disturbances across the Arctic and Subarctic}, series = {Nature Communications}, volume = {9}, journal = {Nature Communications}, publisher = {Nature Publ. Group}, address = {London}, issn = {2041-1723}, doi = {10.1038/s41467-018-07663-3}, pages = {11}, year = {2018}, abstract = {Local observations indicate that climate change and shifting disturbance regimes are causing permafrost degradation. However, the occurrence and distribution of permafrost region disturbances (PRDs) remain poorly resolved across the Arctic and Subarctic. Here we quantify the abundance and distribution of three primary PRDs using time-series analysis of 30-m resolution Landsat imagery from 1999 to 2014. Our dataset spans four continental-scale transects in North America and Eurasia, covering similar to 10\% of the permafrost region. Lake area loss (-1.45\%) dominated the study domain with enhanced losses occurring at the boundary between discontinuous and continuous permafrost regions. Fires were the most extensive PRD across boreal regions (6.59\%), but in tundra regions (0.63\%) limited to Alaska. Retrogressive thaw slumps were abundant but highly localized (< 10(-5)\%). Our analysis synergizes the global-scale importance of PRDs. The findings highlight the need to include PRDs in next-generation land surface models to project the permafrost carbon feedback.}, language = {en} } @article{KathBoitGuilletal.2018, author = {Kath, Nadja J. and Boit, Alice and Guill, Christian and Gaedke, Ursula}, title = {Accounting for activity respiration results in realistic trophic transfer efficiencies in allometric trophic network (ATN) models}, series = {Theoretical ecology}, volume = {11}, journal = {Theoretical ecology}, number = {4}, publisher = {Springer}, address = {Heidelberg}, issn = {1874-1738}, doi = {10.1007/s12080-018-0378-z}, pages = {453 -- 463}, year = {2018}, abstract = {Allometric trophic network (ATN) models offer high flexibility and scalability while minimizing the number of parameters and have been successfully applied to investigate complex food web dynamics and their influence on food web diversity and stability. However, the realism of ATN model energetics has never been assessed in detail, despite their critical influence on dynamic biomass and production patterns. Here, we compare the energetics of the currently established original ATN model, considering only biomass-dependent basal respiration, to an extended ATN model version, considering both basal and assimilation-dependent activity respiration. The latter is crucial in particular for unicellular and invertebrate organisms which dominate the metabolism of pelagic and soil food webs. Based on metabolic scaling laws, we show that the extended ATN version reflects the energy transfer through a chain of four trophic levels of unicellular and invertebrate organisms more realistically than the original ATN version. Depending on the strength of top-down control, the original ATN model yields trophic transfer efficiencies up to 71\% at either the third or the fourth trophic level, which considerably exceeds any realistic values. In contrast, the extended ATN version yields realistic trophic transfer efficiencies 30\% at all trophic levels, in accordance with both physiological considerations and empirical evidence from pelagic systems. Our results imply that accounting for activity respiration is essential for consistently implementing the metabolic theory of ecology in ATN models and for improving their quantitative predictions, which makes them more powerful tools for investigating the dynamics of complex natural communities.}, language = {en} }