TY  - JOUR
A1  - Peters, Simon
A1  - Kaiser, Lena
A1  - Fink, Julian
A1  - Schumacher, Fabian
A1  - Perschin, Veronika
A1  - Schlegel, Jan
A1  - Sauer, Markus
A1  - Stigloher, Christian
A1  - Kleuser, Burkhard
A1  - Seibel, Juergen
A1  - Schubert-Unkmeir, Alexandra
T1  - Click-correlative light and electron microscopy (click-AT-CLEM) for imaging and tracking azido-functionalized sphingolipids in bacteria
JF  - Scientific Reports
N2  - Sphingolipids, including ceramides, are a diverse group of structurally related lipids composed of a sphingoid base backbone coupled to a fatty acid side chain and modified terminal hydroxyl group. Recently, it has been shown that sphingolipids show antimicrobial activity against a broad range of pathogenic microorganisms. The antimicrobial mechanism, however, remains so far elusive. Here, we introduce 'click-AT-CLEM', a labeling technique for correlated light and electron microscopy (CLEM) based on the super-resolution array tomography (srAT) approach and bio-orthogonal click chemistry for imaging of azido-tagged sphingolipids to directly visualize their interaction with the model Gram-negative bacterium Neisseria meningitidis at subcellular level. We observed ultrastructural damage of bacteria and disruption of the bacterial outer membrane induced by two azido-modified sphingolipids by scanning electron microscopy and transmission electron microscopy. Click-AT-CLEM imaging and mass spectrometry clearly revealed efficient incorporation of azido-tagged sphingolipids into the outer membrane of Gram-negative bacteria as underlying cause of their antimicrobial activity.
KW  - antimicrobials
KW  - biological techniques
KW  - imaging
KW  - microbiology
KW  - microbiology techniques
KW  - microscopy
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-259147
VL  - 11
IS  - 1
ER  - 
TY  - JOUR
A1  - Grimm, Jonathan B.
A1  - Klein, Teresa
A1  - Kopek, Benjamin G.
A1  - Shtengel, Gleb
A1  - Hess, Harald F.
A1  - Sauer, Markus
A1  - Lavis, Luke D.
T1  - Synthesis of a far-red photoactivatable silicon-containing rhodamine for super-resolution microscopy
JF  - Angewandte Chemie International Edition
N2  - The rhodamine system is a flexible framework for building small‐molecule fluorescent probes. Changing N‐substitution patterns and replacing the xanthene oxygen with a dimethylsilicon moiety can shift the absorption and fluorescence emission maxima of rhodamine dyes to longer wavelengths. Acylation of the rhodamine nitrogen atoms forces the molecule to adopt a nonfluorescent lactone form, providing a convenient method to make fluorogenic compounds. Herein, we take advantage of all of these structural manipulations and describe a novel photoactivatable fluorophore based on a Si‐containing analogue of Q‐rhodamine. This probe is the first example of a “caged” Si‐rhodamine, exhibits higher photon counts compared to established localization microscopy dyes, and is sufficiently red‐shifted to allow multicolor imaging. The dye is a useful label for super‐resolution imaging and constitutes a new scaffold for far‐red fluorogenic molecules.
KW  - fluorophore
KW  - microscopy
KW  - photoactivation
KW  - Si-rhodamine
KW  - super-resolution imaging
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-191069
VL  - 55
IS  - 5
ER  -