@misc{12817, abstract = {3D-reconstruction of living brain tissue down to individual synapse level would create opportunities for decoding the dynamics and structure-function relationships of the brain’s complex and dense information processing network. However, it has been hindered by insufficient 3D-resolution, inadequate signal-to-noise-ratio, and prohibitive light burden in optical imaging, whereas electron microscopy is inherently static. Here we solved these challenges by developing an integrated optical/machine learning technology, LIONESS (Live Information-Optimized Nanoscopy Enabling Saturated Segmentation). It leverages optical modifications to stimulated emission depletion (STED) microscopy in comprehensively, extracellularly labelled tissue and prior information on sample structure via machine learning to simultaneously achieve isotropic super-resolution, high signal-to-noise-ratio, and compatibility with living tissue. This allows dense deep-learning-based instance segmentation and 3D-reconstruction at synapse level incorporating molecular, activity, and morphodynamic information. LIONESS opens up avenues for studying the dynamic functional (nano-)architecture of living brain tissue.}, author = {Danzl, Johann G}, publisher = {Institute of Science and Technology Austria}, title = {{Research data for the publication "Dense 4D nanoscale reconstruction of living brain tissue"}}, doi = {10.15479/AT:ISTA:12817}, year = {2023}, } @misc{12497, abstract = {Aromatic side chains are important reporters of the plasticity of proteins, and often form important contacts in protein–protein interactions. We studied aromatic residues in the two structurally homologous cross-β amyloid fibrils HET-s, and HELLF by employing a specific isotope-labeling approach and magic-angle-spinning NMR. The dynamic behavior of the aromatic residues Phe and Tyr indicates that the hydrophobic amyloid core is rigid, without any sign of "breathing motions" over hundreds of milliseconds at least. Aromatic residues exposed at the fibril surface have a rigid ring axis but undergo ring flips on a variety of time scales from nanoseconds to microseconds. Our approach provides direct insight into hydrophobic-core motions, enabling a better evaluation of the conformational heterogeneity generated from an NMR structural ensemble of such amyloid cross-β architecture.}, author = {Becker, Lea Marie and Schanda, Paul}, keywords = {aromatic side chains, isotopic labeling, protein dynamics, ring flips, spin relaxation}, publisher = {Institute of Science and Technology Austria}, title = {{Research data to: The rigid core and flexible surface of amyloid fibrils probed by magic-angle-spinning NMR spectroscopy of aromatic residues}}, doi = {10.15479/AT:ISTA:12497}, year = {2023}, } @misc{13126, abstract = {Mapping the complex and dense arrangement of cells and their connectivity in brain tissue demands nanoscale spatial resolution imaging. Super-resolution optical microscopy excels at visualizing specific molecules and individual cells but fails to provide tissue context. Here, we developed Comprehensive Analysis of Tissues across Scales (CATS), a technology to densely map brain tissue architecture from millimeter regional to nanometer synaptic scales in diverse chemically fixed brain preparations, including rodent and human. CATS uses fixation-compatible extracellular labeling and optical imaging, including stimulated emission depletion or expansion microscopy, to comprehensively delineate cellular structures. It enables three-dimensional reconstruction of single synapses and mapping of synaptic connectivity by identification and analysis of putative synaptic cleft regions. Applying CATS to the mouse hippocampal mossy fiber circuitry, we reconstructed and quantified the synaptic input and output structure of identified neurons. We furthermore demonstrate applicability to clinically derived human tissue samples, including formalin-fixed paraffin-embedded routine diagnostic specimens, for visualizing the cellular architecture of brain tissue in health and disease.}, author = {Danzl, Johann G}, publisher = {Institute of Science and Technology Austria}, title = {{Research data for the publication "Imaging brain tissue architecture across millimeter to nanometer scales"}}, doi = {10.15479/AT:ISTA:13126}, year = {2023}, } @misc{13116, abstract = {The emergence of large-scale order in self-organized systems relies on local interactions between individual components. During bacterial cell division, FtsZ -- a prokaryotic homologue of the eukaryotic protein tubulin -- polymerizes into treadmilling filaments that further organize into a cytoskeletal ring. In vitro, FtsZ filaments can form dynamic chiral assemblies. However, how the active and passive properties of individual filaments relate to these large-scale self-organized structures remains poorly understood. Here, we connect single filament properties with the mesoscopic scale by combining minimal active matter simulations and biochemical reconstitution experiments. We show that density and flexibility of active chiral filaments define their global order. At intermediate densities, curved, flexible filaments organize into chiral rings and polar bands. An effectively nematic organization dominates for high densities and for straight, mutant filaments with increased rigidity. Our predicted phase diagram captures these features quantitatively, demonstrating how the flexibility, density and chirality of active filaments affect their collective behaviour. Our findings shed light on the fundamental properties of active chiral matter and explain how treadmilling FtsZ filaments organize during bacterial cell division. }, author = {Dunajova, Zuzana and Prats Mateu, Batirtze and Radler, Philipp and Lim, Keesiang and Brandis, Dörte and Velicky, Philipp and Danzl, Johann G and Wong, Richard W. and Elgeti, Jens and Hannezo, Edouard B and Loose, Martin}, publisher = {Institute of Science and Technology Austria}, title = {{Chiral and nematic phases of flexible active filaments}}, doi = {10.15479/AT:ISTA:13116}, year = {2023}, } @misc{14614, abstract = {Many insects carry an ancient X chromosome—the Drosophila Muller element F—that likely predates their origin. Interestingly, the X has undergone turnover in multiple fly species (Diptera) after being conserved for more than 450 My. The long evolutionary distance between Diptera and other sequenced insect clades makes it difficult to infer what could have contributed to this sudden increase in rate of turnover. Here, we produce the first genome and transcriptome of scorpionflies (genus Panorpa), an insect belonging to a long overlooked sister-order to Diptera: Mecoptera. Combining our genome assembly with genomic short-read data, we obtain genome coverage and identify X-linked super-scaffolds. We further perform a gene homology analysis between the Panorpa X and a closely related Diptera species, and we assess the conservation of the Panorpa X-linked gene content with that of more distantly related insect species. We explored the structure of the Panorpa X by determining its repeat content, GC content, and nucleotide diversity. Finally, we used RNAseq data to detect the presence of dosage compensation in somatic tissues, as well as to explore gene expression tissue-specificity, and sex-bias in gene expression. We find high conservation of gene content between the mecopteran X and the dipteran Muller F element, as well as several shared biological features, such as the presence of dosage compensation and a low amount of genetic diversity, consistent with a low recombination rate. However, the 2 homologous X chromosomes differ strikingly in their size and number of genes they carry. Our results therefore support a common ancestry of the mecopteran and ancestral dipteran X chromosomes, and suggest that Muller element F shrank in size and gene content after the split of Diptera and Mecoptera, which may have contributed to its turnover in dipteran insects.}, author = {Lasne, Clementine and Elkrewi, Marwan N}, keywords = {Panorpa, scorpionfly, genome, transcriptome}, publisher = {Institute of Science and Technology Austria}, title = {{The scorpionfly (Panorpa cognata) genome highlights conserved and derived features of the peculiar dipteran X chromosome}}, doi = {10.15479/AT:ISTA:14614}, year = {2023}, }