Cytoplasmic streaming in plant cells: the role of wall slip

Abstract

We present a computer simulation study, via lattice Boltzmann simulations, of a microscopic model for cytoplasmic streaming in algal cells such as those of Chara corallina. We modelled myosin motors tracking along actin lanes as spheres undergoing directed motion along fixed lines. The sphere dimension takes into account the fact that motors drag vesicles or other organelles, and, unlike previous work, we model the boundary close to which the motors move as walls with a finite slip layer. By using realistic parameter values for actin lane and myosin density, as well as for endoplasmic and vacuole viscosity and the slip layer close to the wall, we find that this simplified view, which does not rely on any coupling between motors, cytoplasm and vacuole other than that provided by viscous Stokes flow, is enough to account for the observed magnitude of streaming velocities in intracellular fluid in living plant cells.

Cytoplasmic Electric Fields and Electroosmosis: Possible Solution for the Paradoxes of the Intracellular Transport of Biomolecules

“…The most popular explanation of the mechanism of the cytoplasmic streaming is that “the directed motion of myosin motors on the actin bundle tracks, located in the cellular wall can somehow entrain the cytoplasmic fluid, and that this in turn sets the vacuole into motion by transferring momentum through the fluid membrane separating it from the cytoplasm” [59]. The quantitative representation of this hypothesis is the sliding wall theory [58], [60] which results in the flow pattern that was confirmed by the recent direct nuclear magnetic resonance velocimetry experiments of flow inside the vacuole of single internodal cells [61]. The mechanism of momentum transfer from myosin to endoplasm and vacuole is not trivial and was theoretically examined in [62], where it was shown that individual myosin molecules running on the actin tracks are by themselves ineffective in setting the cytosol or the vacuole into motion.…”

Biotechnological aspects of cytoskeletal regulation in plants

“…Similarly actin microfilaments follow the formation of the microtubule preprophase band, although they eventually become excluded from the cortical cytoplasmic site corresponding to the cell division plane in the so-called actindepletion zone (Kojo et al, 2013). In the subcortical cytoplasm as well as in cytoplasmic strands of vigorously growing and differentiating cells, F-actin forms highly bundled cables that apparently support cytoplasmic streaming and cell growth and organelle positioning (Higa et al, 2014;Wolff et al, 2012).…”

Particle–wall tribology of slippery hydrogel particle suspensions

“…Slip is essential within many natural systems, including transport of solid foods through the oral, digestion and waste pathways, 4 the movement of blood cells through narrow arteries, 5 the adhesive locomotion of gastropods, 6 or the nutrient delivery by cytoplasmic streaming in plant cells. 7 The importance of the phenomena of wall slip in applications is also seen in the transport of many complex suspensions, such as oil emulsions, foods, pharmaceuticals, sewage treatment and soils. [8][9][10][11] During processing of composites or nanocomposites in extruders and slit dies, it is crucial to account for slip phenomena which cannot be avoided in general.…”