Aspergillus niger conidial germination: 3D live cell exploration

Abstract

Conidial germination describes the transition of dormant spores to hyphal structures. Breaking dormancy is followed by isotropic and polarized growth with a cell wall constantly being remodeled. To explore and understand the rearrangement and timing of key events in A. niger, we use the Nanolive stain-free live cell imaging system - a combination of holography and tomography1. A temperature-controlled growth chamber is used for incubating the fungus on-stage of the microscope. With the 3D Nanoscopy technique, videos of the germination process can be recorded and morphological structures distinguished based on different refractive indices (RI). These structures provide a RI map of cellular details and 3D digital cell reconstruction revealed a finely resolved filamentous network. Overlay of fluorescent signals with the respective RI signal enables further identification of organelles for live, label- free observation in three dimensions.