Ruffling movements

Ameboid movements of protozoa and of cells from higher organisms, the ruffling movements of cell membranes, phagocystosis, and the cytoplasmic streaming characteristic of many plant cells2893 have all been traced to actin filaments or actin cables rather... 

Primary cells will continue or start to divide in culture but exhibit contact inhibition of movement (Abercrombie and Heaysman, 1954). When two such cells approach one another the characteristic ruffling movements of the cell membrane stop in the area of contact. Primary cells therefore do not grow one on top of the other and, in general, cease to divide when a monolayer has been formed. This phenomenon is not restricted to primary cells but applies also to many cell lines. An ideal example is the 3T3 mouse fibroblast cell line which grows rapidly in sparse culture but all division stops as soon as the cells become confluent at about 106 cells per 6 cm dish (Holley and Kieman, 1968). Such cells may for some time remain... 

Cell migration involves transient formation of membrane protmsions (lamellipodia, cell membrane ruffles) at the leading edge of the cell that are thought to require rapid local changes in ion fluxes and cell volume, probably accompanied by rapid transmembrane water movement (Condeelis 1993 Lauffenburger and Horwitz 1996). If transmembrane water movement is a fundamental determinant of cell motility, then a different water channel... 

A turkey feather, or any good-sized downy feather, is a good visual indicator for leaks, but they can be tricky to use because they are so sensitive that any breathing or very slight movement of air from any source can also ruffle the down. It s not exactly high tech, but I have found it to be a very effective method of leak detection. 

---