Neuron Growth. This movie obtained by Joe Fass shows an embryonic chick forebrain neuron , grown in vitro on polyethyleneimine-coated glass, being stretched by a magnetic bead that is motely manipulated with an electromagnet. The 4.5 µm diameter magnetic bead is coated with an antibody to beta1 integrin, which allows the actin cytoskeleton to be engaged. The entire movie c is 30 minutes real time. The cross-hairs in a fixed position relative to the magnet, so that as long as the bead is in the cross-hairs, then the force is constant. In this case the force is 450 pN, which we found to be close to "optimal" in terms of efficient elicitation of growth. (Fass and Odde, Biophysical Journal, 85, 623-636 (2003))

Budding yeast metaphase animation. This movie created by Melissa Gardner shows the predicted dynamics of kinetochore microtubules (green) in the the metaphase budding yeast mitotic spindle. The model assumes that there is a gradient in catastrophe rate, such that catastrophe is high near the equator and low near the spindle pole bodies (red). The kinetochore microtubule plus ends (blue, attached to left spindle pole body, pink, attached to right spindle pole body) sense this gradient and are generally confined to the respective half-spindles to which their minus ends are attached. In addition, it is assumed that tension is exerted on the intervening chromatin, which acts as a spring (yellow) to promote rescue when the tension is high and suppress rescue when the tension is low. In this way, equator crossings of the kinetochore microtubule plus ends is further suppressed, and the congressed, bioriented state is achieved.

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