Confocal laser scanning microscope

• Subject Area: Agriculture, Forestry and Veterinary Medicine
• Term: Funded in 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 560213251

Within our proposal we aim to establish super-resolution stimulated emission depletion microscopy with fast fluorescence lifetime technique as a novel tool in soil- and environmental sciences at the University of Kiel and collaborating research institutes. Due to the fast and efficient counting of the arrival time of photons per pixel, the proposed system allows the production of sharp images of microorganisms even in such heterogeneous environments like soils and sediments at the sub-aggregate scale without embedding and thin sectioning. The clearly different lifetime properties of different components of the soil matrix (i.e. mineral edges, organic coatings) from the stained organisms will allow to differentiate the fluorescence signal. In addition, a recently established new method, called micro-zymography, in combination with the new microscope will allow to determine oxidative enzyme activity in-situ in the rhizosphere at the microscale. Linking this method to fluorescence lifetime imaging will allow to overcome disturbing autofluorescence of the soil matrix. The involved groups aim to use the proposed instrumental configuration for a broad range of research projects: For the visualization and distinction of bacterial communities in the rhizosphere, the rhizoplane, and the endosphere of roots. For the coupling of super-resolution microscopy of soil samples with nanoscale secondary ion mass spectrometry to quantify labelled substrate uptake of previously identified single living cells. Since the resolution of both techniques is at a similar scale, image registration without scaling will be possible.To visualize root microbial interactions via micro-confocal laser scanning microscopy and nanoscopy imaging techniques to discover micro-niches and specific surfaces for bacterial colonization that are provided by the plant. To study the impact of environmental conditions (temperature, drought, pathogens) on enzyme activities in the rhizosphere of root tips (nano-zymography). For co-localization of enzymes, bacteria and mycorrhizal hyphae at the sub-aggregate scale. To analyze mycorrhizal hyphae driven weathering of mineral surfaces in soil. To use fluorescent-tagged lectins and antibodies for visualization of mucilage exudation in the rhizosphere at the nanoscale. Establish phage-fluorescence lifetime imaging as a viable method for specific identification and visualization of intact phage particles to demonstrate the suitability of the method for phage visualization in soil habitats.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: Konfokales Laser-Scanning-Mikroskop
• Instrumentation Group: 5090 Spezialmikroskope
• Applicant Institution: Christian-Albrechts-Universität zu Kiel
• Leader: Professorin Dr. Sandra Spielvogel