A5002506840- Advanced Fluorescence Microscopy Techniques
- Microtubule and mitosis dynamics
- Cellular Mechanics and Interactions
- Optical Polarization and Ellipsometry
- Photosynthetic Processes and Mechanisms
- Reproductive Biology and Fertility
- Digital Holography and Microscopy
- Force Microscopy Techniques and Applications
- Liquid Crystal Research Advancements
- Advanced Electron Microscopy Techniques and Applications
- Cell Image Analysis Techniques
- Micro and Nano Robotics
- Biocrusts and Microbial Ecology
- Near-Field Optical Microscopy
- Photoacoustic and Ultrasonic Imaging
- Protist diversity and phylogeny
- Cell Adhesion Molecules Research
- Optical measurement and interference techniques
- Optical Coatings and Gratings
- Lipid Membrane Structure and Behavior
- Fungal and yeast genetics research
- Nuclear Structure and Function
- Advanced X-ray Imaging Techniques
- Plant Reproductive Biology
- Photoreceptor and optogenetics research
Marine Biological Laboratory
2016-2025
Brown University
2008-2018
Fritz Thyssen Foundation
2015
John Brown University
2014
University of Chicago
2012
Multi Base (China)
2011
Brandeis University
1986-2008
Ludwig-Maximilians-Universität München
2001
Women & Infants Hospital of Rhode Island
2001
Providence College
2001
Microbes in nature frequently function as members of complex multitaxon communities, but the structural organization these communities at micrometer level is poorly understood because limitations labeling and imaging technology. We report here a combinatorial strategy coupled with spectral image acquisition analysis that greatly expands number fluorescent signatures distinguishable single image. As an proof principle, we first demonstrated visualization Escherichia coli labeled by...
Summary A new type of polarized light microscope (‘new pol‐scope’) for fast and orientation‐independent measurement birefringent fine structure has been developed. The design the pol‐scope incorporates a precision universal compensator made from two liquid crystal variable retarders. video camera digital image processing system provide measurements specimen anisotropy (retardance magnitude azimuth) at all points forming field view. images document structural molecular organization within...
We propose image processing algorithms for measuring two-dimensional distributions of linear birefringence using a pair variable retarders. Several that use between two and five recorded frames allow us to optimize measurements speed, sensitivity, accuracy. show images asters, which consist radial arrays microtubule polymers with polarized light microscope equipped universal compensator. Our experimental results confirm our theoretical expectations. The lowest noise level 0.036 nm was...
The septins are conserved, GTP-binding proteins important for cytokinesis, membrane compartmentalization, and exocytosis. However, it is unknown how arranged within higher-order structures in cells. To determine the organization of live cells, we developed a polarized fluorescence microscopy system to monitor orientation GFP dipole moments with high spatial temporal resolution. When was fused septins, arrangement dipoles reflected underlying septin organization. We demonstrated filamentous...
Significance Integrins are adhesion receptors linking cells to their environment, which function as sensors of physical and chemical information regulate development, immune response, vascular function. How integrins receive transduce directional forces including flow or tissue tension has remained elusive. We used polarization-based microscopy techniques discover that activated αVβ3 aligned with one another in focal adhesions migrating fibroblasts. Integrin coalignment is sensitive...
Polarized light microscopy provides unique opportunities for analyzing the molecular order in man-made and natural materials, including biological structures inside living cells, tissues, whole organisms. 20 years ago, LC-PolScope was introduced as a modern version of traditional polarizing microscope enhanced by liquid crystal devices control polarization, electronic imaging digital image processing fast comprehensive acquisition analysis. The is commonly used birefringence imaging, spatial...
Significance In living cells, the 3D architecture of molecular assemblies, such as chromosomes, lipid bilayers, and cytoskeleton, is regulated through interaction among their component molecules. Monitoring position orientation constituent molecules important for understanding mechanisms that govern structure function these assemblies. We have developed an instantaneous fluorescence polarization microscope to track fluorescently labeled particles, including single molecules, which form...
Vinculin is filamentous (F)-actin-binding protein enriched in integrin-based adhesions to the extracellular matrix (ECM). Whereas studies 2-dimensional (2D) tissue culture models have suggested that vinculin negatively regulates cell migration by promoting cytoskeleton-ECM coupling strengthen and stabilize adhesions, its role regulating more physiologic, 3-dimensional (3D) environments unclear. To address of 3D migration, we analyzed morphodynamics, ECM remodeling primary murine embryonic...
Abstract Integrin αβ heterodimer cell surface receptors mediate adhesive interactions that provide traction for migration. Here, we test whether the integrin, when engaged to an extracellular ligand and cytoskeleton, adopts a specific orientation dictated by direction of actin flow on migrating cells. We insert GFP into rigid, ligand-binding head model with Rosetta its transition dipole relative integrin head, measure fluorescence polarization microscopy. Cytoskeleton ligand-bound integrins...
Polarized fluorescence microscopy is a valuable tool for measuring molecular orientations in biological samples, but techniques recovering three-dimensional and positions of fluorescent ensembles are limited. We report polarized dual-view light-sheet system determining the diffraction-limited distribution dipoles that label structures. share set visualization, histogram, profiling tools interpreting these orientations. model distributions based on polarization-dependent efficiency excitation...
Orientational distributions of the rod-shaped tobacco-mosaic-virus particle in magnetically aligned nematic solutions ($0.05M$ borate buffer, $p\mathrm{H} 8.5$) were measured by analysis angular spread x-ray diffraction patterns. We Gaussian orientational with order parameters varying between 0.77 a solution coexisting and isotropic phase, to 0.95 single-phase at higher concentration. Our experimental results are good agreement model calculations based on modified Onsager theory for...
We have developed an imaging system for 3D time-lapse polarization microscopy of living biological samples. Polarization reveals the position, alignment and orientation submicroscopic features in label-free as well fluorescently labeled specimens. Optical anisotropies are calculated from a series images where sample is illuminated by light different states. Due to number necessary collect both multiple states focal planes, most often prohibitively slow. Our MF-PolScope employs multifocus...
The number of fluorescent labels that can unambiguously be distinguished in a single image when acquired through band pass filters is severely limited by the spectral overlap available fluorophores. recent development microscopy and application linear unmixing algorithms to spectrally recorded data have allowed simultaneous imaging fluorophores with highly overlapping spectra. However, distinguishable still unavoidable decrease signal noise ratio fluorescence signals are fractionated over...
Recent studies have investigated the dendritic actin cytoskeleton of cell edge's lamellipodial (LP) region by experimentally decreasing activity filament nucleator and branch former, Arp2/3 complex. Here we extend these via pharmacological inhibition complex in sea urchin coelomocytes, cells that possess an unusually broad LP display correspondingly exaggerated centripetal flow. Using light electron microscopy, demonstrate drug CK666 dramatically altered architecture, slowed flow, drove a...
Polarized light microscopy provides unique opportunities for analyzing the molecular order in heterogeneous systems, such as living cells and tissues, without using exogenous dyes or labels. This article briefly discusses theory of polarized elaborates on its practice a traditional microscope more specialized polarization microscopes LC-PolScope, Oosight, Abrio. The components specific to light, polarizer compensator, are introduced, quantitative techniques measuring birefringence specimen...
We have investigated the dynamic behavior of cytoskeletal fine structure in lamellipodium nerve growth cones using a new type polarized light microscope (the Pol-Scope). Pol-Scope images display with exquisite resolution and definition birefringent structures, such as filaments membranes, without having to treat cell exogenous dyes or fluorescent labels. Furthermore, measured birefringence protein fibers thin lamellipodial region can be interpreted terms number bundles. confirmed that are...