Title: KNIME Image Processing: Integrative Open Source Image Analysis

Date: February 1st 2017 13h

Location: Seminar room (basement) ZBSA Building, Habsburgerstr. 49, 79104 Freiburg

Title: Requirements and Challenges of Management Software

Date: February 7th 2017 14h

Location: Seminar room (basement) ZBSA Building, Habsburgerstr. 49, 79104 Freiburg

 

 

Title: Recent Developments in Lightsheet Microscopy

Date: May 10th 2017 10h

Location: Seminar room (basement) ZBSA Building, Habsburgerstr. 49, 79104 Freiburg

Title: Image-Based Modeling of Organogenesis

Date: May 10th 2017 11h30

Location: Seminar room (basement) ZBSA Building, Habsburgerstr. 49, 79104 Freiburg

Title: Revealing molecular order across biological scales with computational microscopy

Date: June 20th 2017 11h

Location: Seminar room (basement) ZBSA Building, Habsburgerstr. 49, 79104 Freiburg

 

 

Abstract: Living systems differ from inanimate ones by their ability to create and sustain ordered assemblies of molecules at the expense of chemical energy. While ‘-omics’ approaches are generating the ‘parts list’ of biomolecular assemblies at a rapid pace, how these parts come together to form functional cellular mechanisms remains an outstanding question in many fields of biology. For example, the principal components of the cellular contractile machinery that shapes, divides, and moves cells have long been identified, viz., actomyosin network, plasma membrane, and adhesion complexes. But, the dynamic architecture of this machinery remains challenging to measure, especially in three-dimensional (3D) (patho)physiological environments.

Our recent work has led to fluorescence-based computational microscopy assays that reveal nanoscale architecture of molecules within the context of microscale assemblies. We exploit intrinsic polarization of fluorescence to measure sub-resolution orientation and alignment of molecules. We have developed a microscope, dubbed instantaneous fluorescence polarization microscope (instantaneous fluorescence PolScope), to acquire four polarization-resolved measurements with single molecule sensitivity. We retrieve orientation, concentration, and kinetics of cytoskeletal networks by combining instantaneous fluorescence PolScope and computational analysis of the spatiotemporal distribution of fluorophores. This computational microscopy approach revealed nanoscale orientation of actin filaments relative to the retrograde flow of the network at the leading edge of cells migrating on 2D surfaces. Analysis of actin filament orientation at the leading edge has been possible only in fixed cells with electron microscopy. Further, in a multi-institutional collaboration, synergistic use of fluorescence polarization microscopy and computational analysis revealed that integrin transmembrane receptors are ‘actively aligned’ by their engagement with retrograde flow and extracellular ligand. The active alignment of integrin receptors may be a general mechanism used by cells to sense directional cues within extracellular matrix and is uniquely accessible with fluorescence polarization microscopy in live cells.

We are now undertaking joint development of microscopes and computational methods that address the challenge of measuring 3D shape of cells and 3D order of molecules within. Combined with organotypic models of (patho)physiological processes, these approaches can provide direct visualization of emergence of order during healthy and diseased states of tissues, and enable discovery of interventions that drive the tissue from a diseased state to a healthy state.