scholarly journals Direct Observation of Nanoparticle Self-Assembly Dynamics at the Water−Air Interface Using Differential Interference Contrast Microscopy

2009 ◽  
Vol 113 (4) ◽  
pp. 1209-1216 ◽  
Author(s):  
Lehui Xiao ◽  
Rui Zhou ◽  
Yan He ◽  
Yongjun Li ◽  
Edward S. Yeung
Keyword(s):  
Direct Observation ◽  
Self Assembly ◽  
Differential Interference Contrast ◽  
Differential Interference Contrast Microscopy ◽  
Air Interface ◽  
Contrast Microscopy ◽  
Interference Contrast Microscopy

Research note: Reversible birefringence suggests a role for molecular self-assembly in forisome contractility

2007 ◽  
Vol 34 (4) ◽  
pp. 302 ◽  
Author(s):  
Winfried S. Peters ◽  
Reinhard Schnetter ◽  
Michael Knoblauch
Keyword(s):  
Vicia Faba ◽  
Self Assembly ◽  
Effective Diameter ◽  
Differential Interference Contrast ◽  
Differential Interference Contrast Microscopy ◽  
Form Birefringence ◽  
Vicia Faba L ◽  
Contrast Microscopy ◽  
Interference Contrast Microscopy ◽  
Electron Microscopical

Forisomes are contractile protein bodies that control the effective diameter of the sieve elements of the faboid legumes by reversible, Ca2+-driven changes of shape. Forisomes consist of fibrils; we inferred from available electron-microscopical data (which necessarily provide images of fixed, non-functional forisomes) that a reversible assembly of ordered fibrillar arrays might be involved in the contractile mechanism. Here we examined functional forisomes isolated from Vicia faba L. by differential interference contrast microscopy and polarisation microscopy. We found them birefringent in the longitudinally expanded but not in the contracted state, showing ‘parallel extinction’ with the direction of vibration of the slow ray coinciding with their long axis (positive birefringence). These findings met predictions derived from the theory of form birefringence in rodlet composite bodies, and supported the idea of molecular self-assembly as a factor in forisome contractility.

scholarly journals Minus-end capture of preformed kinetochore fibers contributes to spindle morphogenesis

2003 ◽  
Vol 160 (5) ◽  
pp. 671-683 ◽  
Author(s):  
Alexey Khodjakov ◽  
Lily Copenagle ◽  
Michael B. Gordon ◽  
Duane A. Compton ◽  
Tarun M. Kapoor
Keyword(s):  
Three Dimensional ◽  
Differential Interference Contrast ◽  
Differential Interference Contrast Microscopy ◽  
Spindle Formation ◽  
Capture Mechanism ◽  
Contrast Microscopy ◽  
Interference Contrast Microscopy ◽  
Kinesin Eg5 ◽  
Mitotic Kinesin Eg5 ◽  
Dependent Mechanism

Near-simultaneous three-dimensional fluorescence/differential interference contrast microscopy was used to follow the behavior of microtubules and chromosomes in living α-tubulin/GFP-expressing cells after inhibition of the mitotic kinesin Eg5 with monastrol. Kinetochore fibers (K-fibers) were frequently observed forming in association with chromosomes both during monastrol treatment and after monastrol removal. Surprisingly, these K-fibers were oriented away from, and not directly connected to, centrosomes and incorporated into the spindle by the sliding of their distal ends toward centrosomes via a NuMA-dependent mechanism. Similar preformed K-fibers were also observed during spindle formation in untreated cells. In addition, upon monastrol removal, centrosomes established a transient chromosome-free bipolar array whose orientation specified the axis along which chromosomes segregated. We propose that the capture and incorporation of preformed K-fibers complements the microtubule plus-end capture mechanism and contributes to spindle formation in vertebrates.

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