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  1. Article ; Online: When Weak Is Strong: A Plea for Low-Affinity Binders for Optical Microscopy.

    Albertazzi, Lorenzo / Heilemann, Mike

    Angewandte Chemie (International ed. in English)

    2023  Volume 62, Issue 35, Page(s) e202303390

    Abstract: The exploitation of low-affinity molecular interactions in protein labeling is an emerging topic in optical microscopy. Such non-covalent and low-affinity interactions can be realized with various concepts from chemistry and for different molecule ... ...

    Abstract The exploitation of low-affinity molecular interactions in protein labeling is an emerging topic in optical microscopy. Such non-covalent and low-affinity interactions can be realized with various concepts from chemistry and for different molecule classes, and lead to a constant renewal of fluorescence signals at target sites. Further benefits are a versatile use across microscopy methods, in 3D, live and many-target applications. In recent years, several classes of low-affinity labels were developed and a variety of powerful applications demonstrated. Still, this research field is underdeveloped, while the potential is huge.
    Language English
    Publishing date 2023-06-02
    Publishing country Germany
    Document type Journal Article ; Review
    ZDB-ID 2011836-3
    ISSN 1521-3773 ; 1433-7851
    ISSN (online) 1521-3773
    ISSN 1433-7851
    DOI 10.1002/anie.202303390
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Glycan-directed SARS-CoV-2 inhibition by leek extract and lectins with insights into the mode-of-action of Concanavalin A.

    Klevanski, Maja / Kim, Heeyoung / Heilemann, Mike / Kuner, Thomas / Bartenschlager, Ralf

    Antiviral research

    2024  Volume 225, Page(s) 105856

    Abstract: Four years after its outbreak, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains a global challenge for human health. At its surface, SARS-CoV-2 features numerous extensively glycosylated spike proteins. This glycan coat supports ... ...

    Abstract Four years after its outbreak, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains a global challenge for human health. At its surface, SARS-CoV-2 features numerous extensively glycosylated spike proteins. This glycan coat supports virion docking and entry into host cells and at the same time renders the virus less susceptible to neutralizing antibodies. Given the high genetic plasticity of SARS-CoV-2 and the rapid emergence of immune escape variants, targeting the glycan shield by carbohydrate-binding agents emerges as a promising strategy. However, the potential of carbohydrate-targeting reagents as viral inhibitors remains underexplored. Here, we tested seven plant-derived carbohydrate-binding proteins, called lectins, and one crude plant extract for their antiviral activity against SARS-CoV-2 in two types of human lung cells: A549 cells ectopically expressing the ACE2 receptor and Calu-3 cells. We identified three lectins and an Allium porrum (leek) extract inhibiting SARS-CoV-2 infection in both cell systems with selectivity indices (SI) ranging between >2 and >299. Amongst these, the lectin Concanavalin A (Con A) exerted the most potent and broad activity against a panel of SARS-CoV-2 variants. We used multiplex super-resolution microscopy to address lectin interactions with SARS-CoV-2 and its host cells. Notably, we discovered that Con A not only binds to SARS-CoV-2 virions and their host cells, but also causes SARS-CoV-2 aggregation. Thus, Con A exerts a dual mode-of-action comprising both, antiviral and virucidal, mechanisms. These results establish Con A and other plant lectins as candidates for COVID-19 prevention and basis for further drug development.
    MeSH term(s) Humans ; SARS-CoV-2/genetics ; COVID-19 ; Onions/metabolism ; Concanavalin A/metabolism ; Lectins/metabolism ; Polysaccharides ; Antiviral Agents/pharmacology ; Plant Extracts ; Spike Glycoprotein, Coronavirus
    Chemical Substances Concanavalin A (11028-71-0) ; Lectins ; Polysaccharides ; Antiviral Agents ; Plant Extracts ; Spike Glycoprotein, Coronavirus ; spike protein, SARS-CoV-2
    Language English
    Publishing date 2024-03-05
    Publishing country Netherlands
    Document type Journal Article
    ZDB-ID 306628-9
    ISSN 1872-9096 ; 0166-3542
    ISSN (online) 1872-9096
    ISSN 0166-3542
    DOI 10.1016/j.antiviral.2024.105856
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    In stock of ZB MED Cologne/Königswinter

    Zs.A 1627: Show issues Location:
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  3. Book ; Online: FORSYS-Nachwuchsgruppe: Fluoreszenzmethode zur quantitativen Untersuchung von Prozessen der Virus-Zell-Wechselwirkung

    Heilemann, Mike

    Veröffentlichung der Ergebnisse von Forschungsvorhaben im BMBF-Programm ; Projektlaufzeit: 01.07.2008 bis 31.12.2013

    2014  

    Author's details Autor/Projektleitung: Heilemann, Mike
    Language German
    Size Online-Ressource (11 S., 269 KB)
    Publisher Technische Informationsbibliothek u. Universitätsbibliothek ; Univ., FB 14 Biochemie, Chemie und Pharmazie, Inst. für Physikalische und Theoretische Chemie
    Publishing place Hannover ; Frankfurt am Main
    Document type Book ; Online
    Note Förderkennzeichen BMBF 0315262 ; Unterschiede zwischen dem gedruckten Dokument und der elektronischen Ressource können nicht ausgeschlossen werden
    Database Library catalogue of the German National Library of Science and Technology (TIB), Hannover

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  4. Article ; Online: Assessing Antigen Presentation on the Surface of Plasmodium falciparum-Infected Erythrocytes by Photoactivated Localization Microscopy (PALM).

    Karathanasis, Christos / Sanchez, Cecilia P / Heilemann, Mike / Lanzer, Michael

    Methods in molecular biology (Clifton, N.J.)

    2022  Volume 2470, Page(s) 457–466

    Abstract: Super-resolution microscopy in the form of photoactivated localization microscopy (PALM) offers the possibility of counting single molecules in a cell, a cellular compartment or a molecular complex. PALM can, therefore, underpin molecular and biochemical ...

    Abstract Super-resolution microscopy in the form of photoactivated localization microscopy (PALM) offers the possibility of counting single molecules in a cell, a cellular compartment or a molecular complex. PALM can, therefore, underpin molecular and biochemical processes with a numeric and stoichiometric understanding of the interacting players. Here, we introduce the physical principles underlying PALM and provide a step-by-step protocol of how to apply PALM to questions related to the biology and pathophysiology of P. falciparum and other malaria parasites.
    MeSH term(s) Antigen Presentation ; Erythrocytes/parasitology ; Humans ; Malaria, Falciparum/parasitology ; Microscopy ; Plasmodium falciparum ; Protozoan Proteins/chemistry
    Chemical Substances Protozoan Proteins
    Language English
    Publishing date 2022-07-26
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ISSN 1940-6029
    ISSN (online) 1940-6029
    DOI 10.1007/978-1-0716-2189-9_34
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  5. Article ; Online: Fast DNA-PAINT imaging using a deep neural network.

    Narayanasamy, Kaarjel K / Rahm, Johanna V / Tourani, Siddharth / Heilemann, Mike

    Nature communications

    2022  Volume 13, Issue 1, Page(s) 5047

    Abstract: DNA points accumulation for imaging in nanoscale topography (DNA-PAINT) is a super-resolution technique with relatively easy-to-implement multi-target imaging. However, image acquisition is slow as sufficient statistical data has to be generated from ... ...

    Abstract DNA points accumulation for imaging in nanoscale topography (DNA-PAINT) is a super-resolution technique with relatively easy-to-implement multi-target imaging. However, image acquisition is slow as sufficient statistical data has to be generated from spatio-temporally isolated single emitters. Here, we train the neural network (NN) DeepSTORM to predict fluorophore positions from high emitter density DNA-PAINT data. This achieves image acquisition in one minute. We demonstrate multi-colour super-resolution imaging of structure-conserved semi-thin neuronal tissue and imaging of large samples. This improvement can be integrated into any single-molecule imaging modality to enable fast single-molecule super-resolution microscopy.
    MeSH term(s) DNA ; Fluorescent Dyes ; Microscopy, Fluorescence ; Neural Networks, Computer ; Single Molecule Imaging
    Chemical Substances Fluorescent Dyes ; DNA (9007-49-2)
    Language English
    Publishing date 2022-08-27
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2553671-0
    ISSN 2041-1723 ; 2041-1723
    ISSN (online) 2041-1723
    ISSN 2041-1723
    DOI 10.1038/s41467-022-32626-0
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Optical super-resolution microscopy unravels the molecular composition of functional protein complexes.

    Dietz, Marina S / Heilemann, Mike

    Nanoscale

    2019  Volume 11, Issue 39, Page(s) 17981–17991

    Abstract: Optical super-resolution microscopy has revolutionized our understanding of cell biology. Next to visualizing cellular structures with near-molecular spatial resolution, an additional benefit is the molecular characterization of biomolecular complexes ... ...

    Abstract Optical super-resolution microscopy has revolutionized our understanding of cell biology. Next to visualizing cellular structures with near-molecular spatial resolution, an additional benefit is the molecular characterization of biomolecular complexes directly in an intact cell. Single-molecule localization microscopy, as one technology out of the toolbox of super-resolution methods, generates images by detecting the position of single fluorophore labels and is particularly suited for molecular quantification. We review imaging and analysis methods employing single-molecule localization microscopy and extract molecule numbers.
    MeSH term(s) Animals ; Fluorescent Dyes/chemistry ; Humans ; Microscopy, Fluorescence/instrumentation ; Microscopy, Fluorescence/methods ; Molecular Imaging/instrumentation ; Molecular Imaging/methods ; Proteins/chemistry ; Proteins/metabolism
    Chemical Substances Fluorescent Dyes ; Proteins
    Language English
    Publishing date 2019-10-01
    Publishing country England
    Document type Journal Article ; Review
    ZDB-ID 2515664-0
    ISSN 2040-3372 ; 2040-3364
    ISSN (online) 2040-3372
    ISSN 2040-3364
    DOI 10.1039/c9nr06364a
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  7. Article ; Online: DBlink: dynamic localization microscopy in super spatiotemporal resolution via deep learning.

    Saguy, Alon / Alalouf, Onit / Opatovski, Nadav / Jang, Soohyen / Heilemann, Mike / Shechtman, Yoav

    Nature methods

    2023  Volume 20, Issue 12, Page(s) 1939–1948

    Abstract: Single-molecule localization microscopy (SMLM) has revolutionized biological imaging, improving the spatial resolution of traditional microscopes by an order of magnitude. However, SMLM techniques require long acquisition times, typically a few minutes, ... ...

    Abstract Single-molecule localization microscopy (SMLM) has revolutionized biological imaging, improving the spatial resolution of traditional microscopes by an order of magnitude. However, SMLM techniques require long acquisition times, typically a few minutes, to yield a single super-resolved image, because they depend on accumulation of many localizations over thousands of recorded frames. Hence, the capability of SMLM to observe dynamics at high temporal resolution has always been limited. In this work, we present DBlink, a deep-learning-based method for super spatiotemporal resolution reconstruction from SMLM data. The input to DBlink is a recorded video of SMLM data and the output is a super spatiotemporal resolution video reconstruction. We use a convolutional neural network combined with a bidirectional long short-term memory network architecture, designed for capturing long-term dependencies between different input frames. We demonstrate DBlink performance on simulated filaments and mitochondria-like structures, on experimental SMLM data under controlled motion conditions and on live-cell dynamic SMLM. DBlink's spatiotemporal interpolation constitutes an important advance in super-resolution imaging of dynamic processes in live cells.
    MeSH term(s) Microscopy ; Deep Learning ; Single Molecule Imaging/methods ; Neural Networks, Computer ; Cytoskeleton
    Language English
    Publishing date 2023-07-27
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2169522-2
    ISSN 1548-7105 ; 1548-7091
    ISSN (online) 1548-7105
    ISSN 1548-7091
    DOI 10.1038/s41592-023-01966-0
    Database MEDical Literature Analysis and Retrieval System OnLINE

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    In stock of ZB MED Cologne/Königswinter

    Zs.A 6022: Show issues Location:
    Je nach Verfügbarkeit (siehe Angabe bei Bestand)
    bis Jg. 2021: Bestellungen von Artikeln über das Online-Bestellformular
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  8. Article ; Online: Multi-Color, Bleaching-Resistant Super-Resolution Optical Fluctuation Imaging with Oligonucleotide-Based Exchangeable Fluorophores.

    Glogger, Marius / Spahn, Christoph / Enderlein, Jörg / Heilemann, Mike

    Angewandte Chemie (International ed. in English)

    2021  Volume 60, Issue 12, Page(s) 6310–6313

    Abstract: Super-resolution optical fluctuation imaging (SOFI) is a super-resolution microscopy technique that overcomes the diffraction limit by analyzing intensity fluctuations of statistically independent emitters in a time series of images. The final images are ...

    Abstract Super-resolution optical fluctuation imaging (SOFI) is a super-resolution microscopy technique that overcomes the diffraction limit by analyzing intensity fluctuations of statistically independent emitters in a time series of images. The final images are background-free and show confocality and enhanced spatial resolution (super-resolution). Fluorophore photobleaching, however, is a key limitation for recording long time series of images that will allow for the calculation of higher order SOFI results with correspondingly increased resolution. Here, we demonstrate that photobleaching can be circumvented by using fluorophore labels that reversibly and transiently bind to a target, and which are being replenished from a buffer which serves as a reservoir. Using fluorophore-labeled short DNA oligonucleotides, we labeled cellular structures with target-specific antibodies that contain complementary DNA sequences and record the fluctuation events caused by transient emitter binding. We show that this concept bypasses extensive photobleaching and facilitates two-color imaging of cellular structures with SOFI.
    MeSH term(s) Antibodies/analysis ; Cell Line, Tumor ; Color ; Fluorescence Recovery After Photobleaching ; Fluorescent Dyes/chemistry ; Humans ; Microscopy, Fluorescence ; Oligonucleotides/chemistry ; Optical Imaging
    Chemical Substances Antibodies ; Fluorescent Dyes ; Oligonucleotides
    Language English
    Publishing date 2021-02-03
    Publishing country Germany
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2011836-3
    ISSN 1521-3773 ; 1433-7851
    ISSN (online) 1521-3773
    ISSN 1433-7851
    DOI 10.1002/anie.202013166
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  9. Article ; Online: Microbial Cationic Peptides as a Natural Defense Mechanism against Insect Antimicrobial Peptides.

    Vo, Tien Duy / Spahn, Christoph / Heilemann, Mike / Bode, Helge B

    ACS chemical biology

    2021  Volume 16, Issue 3, Page(s) 447–451

    Abstract: Bacteria produce a plethora of specialized metabolites (SM), with the ecological function of most of them not known. A major group of SM are peptides derived from nonribosomal peptide synthetases (NRPS). In entomopathogenic bacteria of the ... ...

    Abstract Bacteria produce a plethora of specialized metabolites (SM), with the ecological function of most of them not known. A major group of SM are peptides derived from nonribosomal peptide synthetases (NRPS). In entomopathogenic bacteria of the genus
    MeSH term(s) Amino Acid Sequence ; Animals ; Antimicrobial Cationic Peptides/chemistry ; Antimicrobial Cationic Peptides/pharmacology ; Biological Products/chemistry ; Defense Mechanisms ; Escherichia coli/chemistry ; Fluorescent Dyes/chemistry ; Insecta/drug effects ; Lipopeptides/chemistry ; Peptide Synthases/metabolism ; Xenorhabdus/chemistry
    Chemical Substances Antimicrobial Cationic Peptides ; Biological Products ; Fluorescent Dyes ; Lipopeptides ; Peptide Synthases (EC 6.3.2.-) ; non-ribosomal peptide synthase (EC 6.3.2.-)
    Language English
    Publishing date 2021-02-17
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ISSN 1554-8937
    ISSN (online) 1554-8937
    DOI 10.1021/acschembio.0c00794
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  10. Article ; Online: Unbiased choice of global clustering parameters for single-molecule localization microscopy.

    Verzelli, Pietro / Nold, Andreas / Sun, Chao / Heilemann, Mike / Schuman, Erin M / Tchumatchenko, Tatjana

    Scientific reports

    2022  Volume 12, Issue 1, Page(s) 22561

    Abstract: Single-molecule localization microscopy resolves objects below the diffraction limit of light via sparse, stochastic detection of target molecules. Single molecules appear as clustered detection events after image reconstruction. However, identification ... ...

    Abstract Single-molecule localization microscopy resolves objects below the diffraction limit of light via sparse, stochastic detection of target molecules. Single molecules appear as clustered detection events after image reconstruction. However, identification of clusters of localizations is often complicated by the spatial proximity of target molecules and by background noise. Clustering results of existing algorithms often depend on user-generated training data or user-selected parameters, which can lead to unintentional clustering errors. Here we suggest an unbiased algorithm (FINDER) based on adaptive global parameter selection and demonstrate that the algorithm is robust to noise inclusion and target molecule density. We benchmarked FINDER against the most common density based clustering algorithms in test scenarios based on experimental datasets. We show that FINDER can keep the number of false positive inclusions low while also maintaining a low number of false negative detections in densely populated regions.
    MeSH term(s) Microscopy/methods ; Single Molecule Imaging/methods ; Algorithms ; Cluster Analysis ; Nanotechnology
    Language English
    Publishing date 2022-12-29
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2615211-3
    ISSN 2045-2322 ; 2045-2322
    ISSN (online) 2045-2322
    ISSN 2045-2322
    DOI 10.1038/s41598-022-27074-1
    Database MEDical Literature Analysis and Retrieval System OnLINE

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