"From a biology perspective, our results provide insight into collective many-body cellular phenomena such as cytoplasmic streaming
, in which molecular motors generate local active stresses that power coherent flows of the entire cytoplasm, enhancing the nutrient transport that is essential for the development and survival of many organisms."
[[Ca.sup.2+]]i changes periodically with the periodic changes in the direction of cytoplasmic streaming
because of the actin--myosin interaction.
These one-celled organisms use cytoplasmic streaming
to form pseudopods, or tiny legs, that propel the amoeba forward.
This material is generated deep in the colony and is supplied to the growing tips via cytoplasmic streaming
. It has been seen in Coprinus disseminatus that tips do not slow their extension following a branch event (Butler 1961), so it can be concluded that the supply of this material to the tip must exceed the rate of consumption.
Dye was carried into the cytoplasm by diffusion and cytoplasmic streaming
. Embryos were injected while in 30% Danieau's solution (1) and then transferred to 10% Danieau's solution, placed into 1 mm diameter grooves in agarose-coated dishes, and maintained at 28 [degrees]C on a thermoelectric heating stage.
Numerous more recent studies have focused either on general cytology (Meekes, 1985; Prin & Rougier, 1986; Ridge, 1988) or on the organization of the cytoskeleton and the relationship of this to patterns of cell wall synthesis, organelle positioning, or cytoplasmic streaming
(see Heath, 1990; Lloyd, 1991).
In spite of the inhibitory effect of [Ca.sup.++] on cytoplasmic streaming
in a living cell, in the in vitro motility assay, [Ca.sup.++] seemed to have no effect on Chara myosin motility, as shown in Fig.
Exposure to cold inhibited blastodisc cap formation in all embryos treated prior to cytoplasmic streaming
; it also arrested streaming in embryos treated after second polar body formation.
Actin bundles play an important role in many kinds of cell activities, such as muscle contraction, cytoplasmic streaming
, cell migration, and acrosomal reaction.