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  • The Expandables: Cracking the Staphylococcal Cell Wall for Expansion Microscopy.

The Expandables: Cracking the Staphylococcal Cell Wall for Expansion Microscopy.

Frontiers in cellular and infection microbiology (2021-04-03)
Tobias C Kunz, Marcel Rühling, Adriana Moldovan, Kerstin Paprotka, Vera Kozjak-Pavlovic, Thomas Rudel, Martin Fraunholz
ABSTRACT

Expansion Microscopy (ExM) is a novel tool improving the resolution of fluorescence microscopy by linking the sample into a hydrogel that gets physically expanded in water. Previously, we have used ExM to visualize the intracellular Gram-negative pathogens Chlamydia trachomatis, Simkania negevensis, and Neisseria gonorrhoeae. Gram-positive bacteria have a rigid and thick cell wall that impedes classic expansion strategies. Here we developed an approach, which included a series of enzymatic treatments resulting in isotropic 4× expansion of the Gram-positive pathogen Staphylococcus aureus. We further demonstrate the suitability of the technique for imaging of planktonic bacteria as well as endocytosed, intracellular bacteria at a spatial resolution of approximately 60 nm with conventional confocal laser scanning microscopy.

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