Programming Light-Harvesting Efficiency Using DNA Origami.

The remarkable performance and quantum efficiency of biological light-harvesting complexes has prompted a multidisciplinary interest in engineering biologically inspired antenna systems as a possible route to novel solar cell technologies. Key to the effectiveness of biological "nanomachines" in light capture and energy transport is their highly ordered nanoscale architecture of photoactive molecules. Recently, DNA origami has emerged as a powerful tool for organizing multiple chromophores with base-pair accuracy and full geometric freedom. Here, we present a programmable antenna array on a DNA origami platform that enables the implementation of rationally designed antenna structures. We systematically analyze the light-harvesting efficiency with respect to number of donors and interdye distances of a ring-like antenna using ensemble and single-molecule fluorescence spectroscopy and detailed Förster modeling. This comprehensive study demonstrates exquisite and reliable structural control over multichromophoric geometries and points to DNA origami as highly versatile platform for testing design concepts in artificial light-harvesting networks.A. W. C. acknowledges support from the Winton Programme for the Physics of Sustainability. U. F. K. was partly supported by an ERC starting grant (PassMembrane, EY 261101). E. A.H. acknowledges support from Janggen-Pöhn Stiftung and the Schweizerischer Nationalfonds (SNF). P. T. acknowledges support by a starting grant (SiMBA, EU 261162) of the European Research Council (ERC). B. W. gratefully acknowledges support by the Braunschweig International Graduate School of Metrology B-IGSM and the DFG Research Training Group GrK1952/1 ‘Metrology for Complex Nanosystems’. P. M. thankfully acknowledges the support of the EPSRC Centre for Doctoral Training in Sensor Technologies and Applications EP/L015889/1.This is the final version of the article. It first appeared from ACS via https://doi.org/10.1021/acs.nanolett.5b0513

Erfahrungen bei Studienstart und Aktivitäten der Universitäten zu MOOCs in Österreich

Im Beitrag werden die Verbreitung und Nutzung von „Massive Open Online Courses“ (MOOCs) an österreichischen Hochschulen aus der Perspektive von Studierenden und Universitäten skizziert. Dazu wurden zwei Analysen durchgeführt. (1) Zum einen wurden Studienanfänger:innen der TU Graz zu ihren Erfahrungen mit Online-Kursen befragt (N=1.207). Die Ergebnisse zeigen einen deutlichen Zuwachs der Online-Lernvorerfahrungen, insbesondere im Vergleich vor und nach COVID-19. Zum anderen erfolgte (2) eine Analyse der aktuellen Leistungsvereinbarungen aller öffentlichen österreichischen Universitäten. Die Nennung der Begriffe MOOCs bzw. iMooX.at in mehr als der Hälfte der Leistungsvereinbarungen verdeutlicht den zunehmenden Stellenwert von MOOCs

Multispecies biofilm behavior and host interaction support the association of Tannerella serpentiformis with periodontal health

The recently identified bacterium Tannerella serpentiformis is the closest phylogenetic relative of Tannerella forsythia, whose presence in oral biofilms is associated with periodontitis. Conversely, T. serpentiformis is considered health-associated. This discrepancy was investigated in a comparative study of the two Tannerella species. The biofilm behavior was analyzed upon their addition and of Porphyromonas gingivalis-each bacterium separately or in combinations-to an in vitro five-species oral model biofilm. Biofilm composition and architecture was analyzed quantitatively using real-time PCR and qualitatively by fluorescence in situ hybridization/confocal laser scanning microscopy, and by scanning electron microscopy. The presence of T. serpentiformis led to a decrease of the total cell number of biofilm bacteria, while P. gingivalis was growth-promoting. This effect was mitigated by T. serpentiformis when added to the biofilm together with P. gingivalis. Notably, T. serpentiformis outcompeted T. forsythia numbers when the two species were simultaneously added to the biofilm compared to biofilms containing T. forsythia alone. Tannerella serpentiformis appeared evenly distributed throughout the multispecies biofilm, while T. forsythia was surface-located. Adhesion and invasion assays revealed that T. serpentiformis was significantly less effective in invading human gingival epithelial cells than T. forsythia. Furthermore, compared to T. forsythia, a higher immunostimulatory potential of human gingival fibroblasts and macrophages was revealed for T. serpentiformis, based on mRNA expression levels of the inflammatory mediators interleukin 6 (IL-6), IL-8, monocyte chemoattractant protein-1 and tumor necrosis factor α, and production of the corresponding proteins. Collectively, these data support the potential of T. serpentiformis to interfere with biological processes relevant to the establishment of periodontitis

Die Wirkung von MOOCs und iMooX.at aus Sicht von Kursersteller:innen

iMooX.at wird im Rahmen des Projekts „MooX – Die MOOC-Plattform als Service für alle österreichischen Universitäten“ (2020–2023) als nationale Plattform für Hochschulen ausgebaut. Im Beitrag werden bisherige Ergebnisse und Wirkungen des Projekts dargestellt. So wurden bereits 70 MOOCs durchgeführt (geplant waren 33). In problemzentrierten Interviews mit fünf Kursersteller:innen wurden zudem Wirkungen von MOOCs und iMooX.at als Plattform gesammelt. Kursersteller:innen bestätigen in einer Online-Befragung (n=17) im hohen Maße, dass iMooX.at zur Verbreitung von OER beiträgt und positive Wirkungen für unterschiedliche Gruppen hat. Dieses Projekt wurde am 1. Juni 2023 im Rahmen einer Online-Veranstaltung des BMBWF präsentiert. Die Präsentationsunterlagen finden Sie hier

Dysregulation of the Cytokine GM-CSF Induces Spontaneous Phagocyte Invasion and Immunopathology in the Central Nervous System

Chronic inflammatory diseases are influenced by dysregulation of cytokines. Among them, granulocyte macrophage colony stimulating factor (GM-CSF) is crucial for the pathogenic function of T cells in preclinical models of autoimmunity. To study the impact of dysregulated GM-CSF expression in vivo, we generated a transgenic mouse line allowing the induction of GM-CSF expression in mature, peripheral helper T (Th) cells. Antigen-independent GM-CSF release led to the invasion of inflammatory myeloid cells into the central nervous system (CNS), which was accompanied by the spontaneous development of severe neurological deficits. CNS-invading phagocytes produced reactive oxygen species and exhibited a distinct genetic signature compared to myeloid cells invading other organs. We propose that the CNS is particularly vulnerable to the attack of monocyte-derived phagocytes and that the effector functions of GM-CSF-expanded myeloid cells are in turn guided by the tissue microenvironment