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12
result(s) for
"Niedermeier, Sebastian"
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Pre-digest of unprotected DNA by Benzonase improves the representation of living skin bacteria and efficiently depletes host DNA
by
Lagkouvardos, Ilias
,
Niedermeier, Sebastian
,
Köberle, Martin
in
16S rRNA
,
Acne
,
Antimicrobial peptides
2021
Background
The identification of microbiota based on next-generation sequencing (NGS) of extracted DNA has drastically improved our understanding of the role of microbial communities in health and disease. However, DNA-based microbiome analysis cannot
per se
differentiate between living and dead microorganisms. In environments such as the skin, host defense mechanisms including antimicrobial peptides and low cutaneous pH result in a high microbial turnover, likely resulting in high numbers of dead cells present and releasing substantial amounts of microbial DNA. NGS analyses may thus lead to inaccurate estimations of microbiome structures and consequently functional capacities.
Results
We investigated in this study the feasibility of a Benzonase-based approach (BDA) to pre-digest unprotected DNA, i.e., of dead microbial cells, as a method to overcome these limitations, thus offering a more accurate assessment of the living microbiome. A skin mock community as well as skin microbiome samples were analyzed using 16S rRNA gene sequencing and metagenomics sequencing after DNA extraction with and without a Benzonase digest to assess bacterial diversity patterns. The BDA method resulted in less reads from dead bacteria both in the skin mock community and skin swabs spiked with either heat-inactivated bacteria or bacterial-free DNA. This approach also efficiently depleted host DNA reads in samples with high human-to-microbial DNA ratios, with no obvious impact on the microbiome profile. We further observed that low biomass samples generate an α-diversity bias when the bacterial load is lower than 10
5
CFU and that Benzonase digest is not sufficient to overcome this bias.
Conclusions
The BDA approach enables both a better assessment of the living microbiota and depletion of host DNA reads.
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Video abstract
Graphical abstract
Journal Article
Darier’s disease exhibits a unique cutaneous microbial dysbiosis associated with inflammation and body malodour
by
Eyerich, Stefanie
,
Lagkouvardos, Ilias
,
Rogner, Danielle
in
ATP2A2 gene
,
Bioinformatics
,
Biomedical and Life Sciences
2023
Background
Darier’s disease (DD) is a genodermatosis caused by mutations of the
ATP2A2
gene leading to disrupted keratinocyte adhesion. Recurrent episodes of skin inflammation and infections with a typical malodour in DD indicate a role for microbial dysbiosis. Here, for the first time, we investigated the DD skin microbiome using a metabarcoding approach of 115 skin swabs from 14 patients and 14 healthy volunteers. Furthermore, we analyzed its changes in the context of DD malodour and the cutaneous DD transcriptome.
Results
We identified a disease-specific cutaneous microbiome with a loss of microbial diversity and of potentially beneficial commensals. Expansion of inflammation-associated microbes such as
Staphylococcus aureus
and
Staphylococcus warneri
strongly correlated with disease severity. DD dysbiosis was further characterized by abundant species belonging to
Corynebacteria
,
Staphylococci
and
Streptococci
groups displaying strong associations with malodour intensity. Transcriptome analyses showed marked upregulation of epidermal repair, inflammatory and immune defence pathways reflecting epithelial and immune response mechanisms to DD dysbiotic microbiome. In contrast, barrier genes including claudin-4 and cadherin-4 were downregulated.
Conclusions
These findings allow a better understanding of Darier exacerbations, highlighting the role of cutaneous dysbiosis in DD inflammation and associated malodour. Our data also suggest potential biomarkers and targets of intervention for DD.
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Video Abstract
Journal Article
Munich atopy prediction study (MAPS): protocol for a prospective birth cohort addressing clinical and molecular risk factors for atopic dermatitis in early childhood
2022
IntroductionThe pathogenesis of atopic diseases is highly complex, and the exact mechanisms leading to atopic dermatitis (AD) onset in infants remain mostly enigmatic. In addition to an interdependent network of components of skin development in young age and skin barrier dysfunction underlying AD development that is only partially understood, a complex interplay between environmental factors and lifestyle habits with skin barrier and immune dysregulation is suspected to contribute to AD onset. This study aims to comprehensively evaluate individual microbiome and immune responses in the context of environmental determinants related the risk of developing AD in the first 4 years of a child’s life.Methods and analysesThe ‘Munich Atopic Prediction Study’ is a comprehensive clinical and biological investigation of a prospective birth cohort from Munich, Germany. Information on pregnancy, child development, environmental factors, parental exposures to potential allergens and acute or chronic diseases of children and parents are collected by questionnaires together with a meticulous clinical examination by trained dermatologists focusing on allergies, skin health, and in particular signs of AD at 2 months after birth and then every 6 months. In addition, skin barrier functions are assessed through cutometry, corneometry and transepidermal water loss at every visit. These measurements are completed with allergy diagnostics and extensive microbiome analyses from stool and skin swabs as well as transcriptome analyses using skin microbiopsies.The aim is to assess the relevance of different known and yet unknown risk factors of AD onset and exacerbations in infants and to identify possible accessible and robust biomarkers.Ethics and disseminationThe study is approved by the Ethical Committee of the Medical Faculty of the Technical University of Munich (reference 334/16S). All relevant study results will be presented at national and international conferences and in peer-reviewed journals.
Journal Article
Correlative microscopy for in-depth analysis of calcium oxalate crystals in plant tissues
by
Gierlinger, Notburga
,
Niedermeier, Martin
,
Antreich, Sebastian J.
in
Biological Techniques
,
Biomedical and Life Sciences
,
Biomineralization
2025
Background
Calcium oxalate (CaOx) crystals are commonly found in many plant species. These crystals vary in distribution and morphology and to elucidate their role in plants multiple methods have been applied. Raman imaging and polarized light microscopy (PLM) easily visualize the crystals within plant tissues, but both methods are limited in spatial resolution by the diffraction of light. To unravel the distinctive shape and morphology of CaOx crystals down to the nanoscale and how they are embedded within cells, high resolution scanning electron microscopy is needed. To grasp the full potential of multiple methods in CaOx studies, a novel and easy-to-build correlative sampling approach is presented on different nut species (pecan (
Carya illinoinensis
), Turkish hazel (
Corylus colurna
) and black walnut (
Juglans nigra
)), including soft tissues (young developmental stages) as well as hard tissues (mature nutshells).
Result
Young seed coat tissues as well as mature nutshells included distinct morphological CaOx features, like druses and prismatic crystals. By Raman imaging the chemical composition of all investigated crystals was verified as calcium oxalate monohydrate (COM) and Raman band intensity changed according to crystal plane orientation with respect to incident laser polarisation. Calcium oxalate dihydrate (COD) was only found in the young
C. illinoinensis
seed coat and was restricted to a few pixels adjacent to cell walls. These thin cell walls were identified as pectin-rich, while in the mature nutshells the crystals were surrounded by thicker and highly lignified cell walls. The Raman and light microscopy results were correlated with SEM images, which gave additional information on crystal surface structure and/or internal porosity on the nanoscale.
Conclusion
The presented correlative approach preserved the structural integrity of crystals and cellular structures during cutting and transferring between microscopes. Analysing exactly the same sample (position) by Raman, polarized light microscopy and SEM opens the view on the distribution within tissues and cells as well as the molecular structure of the crystals and adjacent cell structures. Such a comprehensive
in-situ
characterization paves the way for a better understanding of mineralization processes of different minerals in all kinds of biological tissues.
Graphical abstract
Journal Article
Primary cilia and SHH signaling impairments in human and mouse models of Parkinson’s disease
by
Ramirez-Suastegui, Ciro
,
Niedermeier, Kristina M.
,
Stautner, Constantin
in
13/1
,
13/100
,
13/106
2022
Parkinson’s disease (PD) as a progressive neurodegenerative disorder arises from multiple genetic and environmental factors. However, underlying pathological mechanisms remain poorly understood. Using multiplexed single-cell transcriptomics, we analyze human neural precursor cells (hNPCs) from sporadic PD (sPD) patients. Alterations in gene expression appear in pathways related to primary cilia (PC). Accordingly, in these hiPSC-derived hNPCs and neurons, we observe a shortening of PC. Additionally, we detect a shortening of PC in
PINK1
-deficient human cellular and mouse models of familial PD. Furthermore, in sPD models, the shortening of PC is accompanied by increased Sonic Hedgehog (SHH) signal transduction. Inhibition of this pathway rescues the alterations in PC morphology and mitochondrial dysfunction. Thus, increased SHH activity due to ciliary dysfunction may be required for the development of pathoetiological phenotypes observed in sPD like mitochondrial dysfunction. Inhibiting overactive SHH signaling may be a potential neuroprotective therapy for sPD.
Here, the authors reveal using single-cell RNA sequencing that Parkinson’s disease (PD) patient-derived neuronal cells show altered primary cilia morphology and signaling suggesting cilia dysfunction may underlie PD pathogenesis.
Journal Article
Industry quantum computing applications
by
Pfeiffer, Ruben
,
Ehmer, Thomas
,
Sepulveda, Johanna
in
Aerospace industry
,
Commercial space industry
,
Commercial spacecraft
2021
Quantum computing promises to overcome computational limitations with better and faster solutions for optimization, simulation, and machine learning problems. Europe and Germany are in the process of successfully establishing research and funding programs with the objective to advance the technology’s ecosystem and industrialization, thereby ensuring digital sovereignty, security, and competitiveness. Such an ecosystem comprises hardware/software solution providers, system integrators, and users from research institutions, start-ups, and industry. The vision of the Quantum Technology and Application Consortium (QUTAC) is to establish and advance the quantum computing ecosystem, supporting the ambitious goals of the German government and various research programs. QUTAC is comprised of ten members representing different industries, in particular automotive manufacturing, chemical and pharmaceutical production, insurance, and technology. In this paper, we survey the current state of quantum computing in these sectors as well as the aerospace industry and identify the contributions of QUTAC to the ecosystem. We propose an application-centric approach for the industrialization of the technology based on proven business impact. This paper identifies 24 different use cases. By formalizing high-value use cases into well-described reference problems and benchmarks, we will guide technological progress and eventually commercialization. Our results will be beneficial to all ecosystem participants, including suppliers, system integrators, software developers, users, policymakers, funding program managers, and investors.
Journal Article
Stacking the odds: full-stack quantum system design space exploration
by
Bandic, Medina
,
Mauerer, Wolfgang
,
Niedermeier, Christoph
in
Algorithms
,
Architecture
,
Circuits
2025
Design space exploration (DSE) plays an important role in optimising quantum circuit execution by systematically evaluating different configurations of compilation strategies and hardware settings. In this paper, we conduct a comprehensive investigation into the impact of various layout methods, qubit routing techniques, and optimisation levels, as well as device-specific properties such as different variants and strengths of noise and imperfections, the topological structure of qubits, connectivity densities, and back-end sizes. By spanning through these dimensions, we aim to understand the interplay between compilation choices and hardware characteristics. A key question driving our exploration is whether the optimal selection of device parameters, mapping techniques, comprising of initial layout strategies and routing heuristics can mitigate device induced errors beyond standard error mitigation approaches. Our results show that carefully selecting software strategies (
e.g.
, mapping and routing algorithms) and tailoring hardware characteristics (such as minimising noise and leveraging topology and connectivity density) significantly improve the fidelity of circuit execution outcomes, and thus the expected correctness or success probability of the computational result. We provide estimates based on key metrics such as circuit depth, gate count and expected fidelity. Our results highlight the importance of hardware–software co-design, particularly as quantum systems scale to larger dimensions, and along the way towards fully error corrected quantum systems: Our study is based on computationally noisy simulations, but considers various implementations of quantum error correction (QEC) using the same approach as for other algorithms. The observed sensitivity of circuit fidelity to noise and connectivity suggests that co-design principles will be equally critical when integrating QEC in future systems. Our exploration provides practical guidelines for co-optimising physical mapping, qubit routing, and hardware configurations in realistic quantum computing scenarios.
Journal Article
Parameterized Complexity of Vertex Cover Variants
2007
Important variants of theVERTEX COVER problem (among others, CONNECTED VERTEX COVER, CAPACITATED VERTEX COVER, and MAXIMUM PARTIAL VERTEX COVER) have been intensively studied in terms of polynomial-time approximability. By way of contrast, their parameterized complexity has so far been completely open. We close this gap here by showing that, with the size of the desired vertex cover as the parameter, CONNECTED VERTEX COVER and CAPACITATED VERTEX COVER are both fixed-parameter tractable while MAXIMUM PARTIAL VERTEX COVER is W[1]-complete. This answers two open questions from the literature. The results extend to several closely related problems. Interestingly, although the considered variants of VERTEX COVER behave very similar in terms of constant factor approximability, they display a wide range of different characteristics when investigating their parameterized complexities. [PUBLICATION ABSTRACT]
Journal Article