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Moving cells display a variety of shapes and modes of locomotion, but it is not clear how motility at the molecular level relates to the locomotion of a whole cell, a problem compounded in studies of cells with complex shapes. A striking feature of fish epidermal keratocyte locomotion is its apparent simplicity. Here we present a kinematic description of(More)
Traction forces produced by moving fibro-blasts have been observed as distortions in flexible substrata including wrinkling of thin, silicone rubber films. Traction forces generated by fibroblast lamellae were thought to represent the forces required to move the cell forwards. However, traction forces could not be detected with faster moving cell types such(More)
Close contacts are the predominant type of cell-substratum adhesion in rapidly moving cells yet little is known about their composition and dynamics. To address these issues we have attempted to identify the molecular components of close contacts formed in rapidly moving fish epithelial keratocytes. In addition we have utilized the simple shape of(More)
Keratocytes provide an excellent system for the study of locomotion because their simple shape allows the description of basic principles that govern their movement. The graded radial extension (GRE) model is a kinematic description of keratocyte locomotion which relates cell shape to movement. It predicts the circumferential motion of morphological(More)
Intracellular calcium regulates many of the molecular processes that are essential for cell movement. It is required for the production of actomyosin-based contractile forces, the regulation of the structure and dynamics of the actin cytoskeletons, and the formation and disassembly of cell-substratum adhesions. Calcium also serves as a second messenger in(More)
The activation of stretch-activated calcium channels (SACs) in keratocytes can induce spatially coordinated increases in traction stress that promote protrusion at the cell front, while simultaneously inducing retraction at the rear. To investigate how this occurs, we correlated calcium-induced changes in traction stress with alterations in cell speed and(More)
The coordination of protrusion with retraction is essential for continuous cell movement. In fish keratocytes the activation of stretch-activated calcium channels, and the resulting increase in intracellular calcium, trigger release of the rear cell margin when forward movement is impeded. Although it is likely that retraction involves a calcium-dependent(More)
In this paper, we proved that the one-dimensional crawling nematode sperm cell model proposed by Mogilner and Verzi (2003) supports traveling wave solutions if there is no disassembly of unbundled filaments in the cell. Uniqueness of traveling wave is established under additional assumptions and numerical examples are also given in the paper. Mathematical(More)
Most casinos owned by sovereign American Indian nations allow smoking, even in U.S. states such as California where state laws restrict workplace smoking. Collaborations between casinos and public health workers are needed to promote smoke-free policies that protect workers and patrons from secondhand tobacco smoke (SHS) exposure and risks. Over seven(More)