Microtubule dynamics in cell division : exploring living cells with polarized light microscopy

Author Posting. © The Author(s), 2008. This is the author's version of the work. It is posted here by permission of Annual Reviews for personal use, not for redistribution. The definitive version was published in Annual Review of Cell and Developmental Biology 24 (2008): 1-28, doi:10.1146/annurev.cellbio.24.110707.175323.This Perspective is an account of my early experience while I studied the dynamic organization and behavior of the mitotic spindle and its submicroscopic filaments using polarized light microscopy. The birefringence of spindle filaments in normally dividing plant and animal cells, and those treated by various agents, revealed: A) the reality of spindle fibers and fibrils in healthy living cells; B) the labile, dynamic nature of the molecular filaments making up the spindle fibers; C) the mode of fibrogenesis and action of orienting centers; and D) force-generating properties based on the disassembly and assembly of the fibrils. These studies, which were carried out directly on living cells using improved polarizing microscopes, in fact, predicted the reversible assembly properties of isolated microtubules

X-Ray Birefringence Imaging (XBI): a new technique for spatially resolved mapping of molecular orientations in materials

The X-ray birefringence imaging (XBI) technique, first reported in 2014, is a sensitive method for spatially resolved mapping of the local orientational properties of anisotropic materials. In the case of organic materials, the technique may be applied to study the orientational properties of individual molecules and/or bonds, including the study of changes in molecular orientations associated with order–disorder phase transitions and characterization of phase transitions in liquid crystalline materials. This chapter presents a basic introduction to the XBI technique, giving a qualitative description of the fundamentals of the technique and discussing experimental aspects of the measurement of XBI data. Several examples are presented to highlight the application of the technique to study the orientational properties of molecules in organic materials