Biology subjects

Fritsche, S.

Publications and source records attributed to Fritsche, S..

3 recordsLinked to original sources

bioRxiv2025

Glycan Atlassing: Nanoscale analysis of glycocalyx architecture enables functional tracing of cell state

The glycocalyx is a complex layer of glycosylated biomolecules surrounding all cells in the human body. It is involved in the regulation of critical cellular processes such as immune response modulation, cell adhesion, and host-pathogen interactions. Despite these insights, the functional relationship between glycocalyx architecture and cellular state has remained elusive so far, mainly attributable to the structural diversity of glycocalyx constituents and their nanoscale organization. Here, we show that DNA-tagged lectin labeling and metabolic oligosaccharide engineering enables multiplexed super-resolution microscopy of glycocalyx constituents, yielding an atlas of glycocalyx architecture with nanometer resolution. Quantitative analysis of the obtained nanoscale map of glycocalyx constituents facilitates the extraction of characteristic spatial relationships that accurately report on cellular state. We demonstrate the capacity of our approach, which we term Glycan Atlassing, across cell and tissue types, ranging from cultured cell lines to primary immune cells, neurons, and primary patient tissue. Glycan Atlassing establishes a powerful strategy for investigating glycocalyx remodeling in development and disease, potentially enabling the development of new glycocalyx-centered targets in diagnosis and therapy.

biophysics↗

bioRxiv2025

Angstrom-resolution imaging of cell-surface glycans

Glycobiology is rooted in the study of monosaccharides, [A]ngstrom-sized molecules that are the building blocks of intricate glycosylation patterns. Glycosylated biomolecules form the glycocalyx, a dense coat encasing every human cell with central relevance - among others - in immunology, oncology, and virology. In order to understand glycosylation function, visualizing its molecular structure is fundamental. However, the ability to visualize the molecular architecture of the glycocalyx has remained elusive. Techniques like mass spectrometry, electron microscopy, and fluorescence microscopy lack the necessary cellular context, specificity, and resolution. Here, we address these limitations by combining metabolic labeling with [A]ngstrom-resolution fluorescence microscopy, enabling the first-ever visualization of individual sugars within glycans on the cell surface. Our work provides unprecedented insights into the molecular architecture of the glycocalyx and constitutes the foundation for future explorations of its function in health and disease.

biophysics↗

bioRxiv2020

Development of genetic tools for the thermophilic filamentous fungus Thermoascus aurantiacus

BackgroundFungal enzymes are vital for industrial biotechnology, including the conversion of plant biomass to biofuels and bio-based chemicals. In recent years, there is increasing interest in using enzymes from thermophilic fungi, which often have higher reaction rates and thermal tolerance compared to currently used fungal enzymes. The thermophilic filamentous fungus Thermoascus aurantiacus produces large amounts of highly thermostable plant cell wall degrading enzymes. However, no genetic tools have yet been developed for this fungus, which prevents strain engineering efforts. The goal of this study was to develop strain engineering tools such as a transformation system, a CRISPR/Cas9 gene editing system and a sexual crossing protocol to improve enzyme production. ResultsHere we report Agrobacterium tumefaciens-mediated transformation (ATMT) of T. aurantiacus using the hph marker gene, conferring resistance to hygromycin B. The newly developed transformation protocol was optimized and used to integrate an expression cassette of the transcriptional xylanase regulator xlnR, which led to up to 500% increased xylanase activity. Furthermore, a CRISPR/Cas9 gene editing system was established in this fungus, and two different gRNAs were tested to delete the pyrG orthologue with 10% and 35% deletion efficiency, respectively. Lastly, a sexual crossing protocol was established using a hygromycin B- and a 5-fluororotic acid-resistant parent strain. Crossing and isolation of progeny on selective media was completed in a week. ConclusionThe genetic tools developed for T. aurantiacus can now be used individually or in combination to further improve thermostable enzyme production by this fungus.

microbiology↗