Observation of Protoplasmic Streaming by Laser-Light Scattering

Mustacich, Robert V.; Ware, B. R.

doi:10.1103/physrevlett.33.617

Cited by 49 publications

(25 citation statements)

References 6 publications

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“…Cytoplasmic streaming has been studied by laser-light scattering to obtain velocity histograms indicating the relative amount of endoplasm flowing at each velocity in the cell 05-20). Laser-light scattering is a more senskive technique for velocity analysis than is simple microscope observation, because light scattering can detect nonvisual events such as fluctuations in refractive index due to concentration fluctuations (15). Velocity histograms obtained NOTHNAGEL AND WEBB with either the Doppler (15,16,18,19) or the correlation (17,20) technique are in close agreement and show that most of the endoplasm moves with velocities failing in a narrow range around the most probable velocity.…”

Section: Velocity Characteristicsmentioning

confidence: 87%

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Hydrodynamic models of viscous coupling between motile myosin and endoplasm in characean algae.

Nothnagel¹,

Webb²

1982

The Journal of Cell Biology

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Cytoplasmic streaming in characean algae is thought to be driven by interaction between stationary subcortical actin bundles and motile endoplasmic myosin. Implicit in this mechanism is a requirement for some form of coupling to transfer motive force from the moving myosin to the endoplasm. Three models of viscous coupling between myosin and endoplasm are presented here, and the hydrodynamic feasibility of each model is analyzed. The results show that individual myosinlike molecules moving along the actin bundles at reasonable velocities cannot exert enough viscous pull on the endoplasm to account for the observed streaming. Attachment of myosin to small spherical organelles improves viscous coupling to the endoplasm, but results for this model show that streaming can be generated only if the myosin-spheres move along the actin bundles in a virtual solid line at about twice the streaming velocity. In the third model, myosin is incorporated into a fibrous or membranous network or gel extending into the endoplasm. This network is pulled forward as the attached myosin slides along the actin bundles. Using network dimensions estimated from published micrographs of characean endoplasm, the results show that this system can easily generate the observed cytoplasmic streaming.Actin-myosin interactions are thought to be responsible for the generation of many types of biological motility, including muscle contraction, amoeboid movement, cytoplasmic streaming, phagocytosis, cell division, and axonal transport (1). Although it is now generally understood how the interaction between actin and myosin leads ultimately to the motion (contraction) of muscle tissue, in most nonmuscle systems the details of motion generation are not yet understood (1). In particular, detailed mechanisms are lacking for the hypothesized actin-myosin-driven flow of intracellular fluid in amoeboid movement, cytoplasmic streaming, and axonal transport. Implicit in these proposed actin-myosin systems is the assumption that the sliding of myosin molecules past actin bundles is somehow coupled to the intracellular fluid to produce a bulk flow.The purpose of this paper is to examine, from a hydrodynamic viewpoint, the feasibility of various supramolecular structures that might function to provide coupling between actin-myosin sliding and bulk fluid flow. The hydrodynamics presented will be modeled for the geometry of cytoplasmic streaming in characean algae. Various microscopic, ultrastructural, and biochemical observations (2-5) have provided evidence that this streaming is driven by actin-myosin. Although other mechanisms have been proposed (6), most available evidence (3) suggests that characean streaming is driven by interaction between motile endoplasmic myosin and stationary subcortical actin bundles (Fig. l). The highly organized pattern of streaming in characean internodal cells makes this a convenient system for hydrodynamic modeling. Some of the results obtained for this system may then fred applications in other, less organized, nonmus...

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Section: Velocity Characteristicsmentioning

confidence: 87%

“…Results predicted, then, for the velocity profde (Eqs. [13][14][15][16] and motive force (Eq. 17) must be consistent with the Empirical Characteristics if this model of streaming is to be hydrodynamically feasible.…”

Section: Vn~ [1 + 6e/a) + 2b]mentioning

confidence: 99%

Hydrodynamic models of viscous coupling between motile myosin and endoplasm in characean algae.

Nothnagel¹,

Webb²

1982

The Journal of Cell Biology

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“…In order to allow free observation of streaming, a window (diameter 100 lam) was burned into the chloroplast layer (Kamitsubo 1972) Measurement of cytoplasmic streaming by laser-velocimetry. Mustacich and Ware (1974, 1977 introduced the laser-Doppler technique for the measurement of cytoplasmic streaming. Here, a real-fringe set-up (Brayton and Goethert 1971;Drain 1980) was used which provides a smaller band-width, a better signal-to-noise ratio and independence of signal frequency from scattered light angle.…”

Section: Methodsmentioning

confidence: 99%

“…As far as we know there is no observation of a light-induced modulation of streaming in photosynthetic cells. Mustacich and Ware (1974, 1977 introduced the measurement of streaming by means of laser-Doppler anemometry (LDA). This method enables the recording of streaming also in the dark over long periods of time (Langley et al 1976;Satelle and Buchan 1976;Satelle et al 1979;Chen 1990), since only a very small spot (<1001am 2) is illuminated.…”

Section: Introductionmentioning

confidence: 99%

Light dependence of protoplasmic streaming in Nitella flexilis L. as measured by means of laser-velocimetry

Plieth

Hansen

1992

Planta

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Laser-velocimetry was applied in order to study the effect of light on the velocity of protoplasmic streaming (pps) in Characean cells. A change from dark to light (= 6 W · m(-2)) leads to an acceleration of streaming by about 15-30% with a time-constant of approx. 300 s. The transition from light to dark causes a transient decrease of velocity below the original dark level. This response occurs with a time constant of about 500 s. It returns to its initial value with a time-constant of about 2000 s. This may indicate that a control loop of cytosolic homeostasis takes a decrease in pCa more seriously than an increase. A possible involvement of temperature effects caused by illumination was excluded by measuring the influence of temperature. Steady-state velocity of streaming changed by 5% per 1° C. Irradiation with infra-red light (λ > 780 nm) did not cause a change in velocity. The absence of a light effect on streaming velocity in the presence of 3-(3',4'-dichlorophenyl)-1,1-dimethylurea (DCMU) shows that photosynthesis and not phytochrome is involved. The role of light-induced changes of pCa is discussed, especially with respect to the hypothesis of Vanselow and Hansen (1989, J. Membr. Biol. 110, 175-187) that photosynthesis acts on the plasmalemma K(+)-channel via light-induced uptake of Ca(2+) into the chloroplasts.

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“…Feher, 1978), using photon correlation. The analytic techniques have been available for about 15 years and have been used to detect translational motions in living systems (Mustacich & Ware, 1974, 1977Langley et al, 1976). In these studies laser beams of relatively large diameter (100 pm) were used to detect cytoplasmic steaming in coenocytic organisms.…”

Section: Introductionmentioning

confidence: 99%

Diffusive motions in living cytoplasm probed by laser Doppler microscopy

Steer¹,

Picton²,

Earnshaw³

1984

Journal of Microscopy

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We have examined cytoplasmic motions in growing pollen tube tips using laser Doppler microscopy, a non-invasive and non-destructive technique. The observed correlation functions were consistent with the existence of diffusive motions in the tip cytoplasm. Further analysis of the data revealed the existence of at least two major and a third, minor, diffusing species in the cytoplasm. Information from quantitative electron microscopy and from published literature values of cytoplasmic viscosity was used to tentatively identify the organelles contributing to the observed diffusive motions. It is concluded that motions of mitochondria and secretory vesicles dominate the observed correlation functions with a minor component detected from either ribosomes or the microfilament network. Sources of variation in the observed data are discussed, as are the physical limitations that prevent a more positive analysis of the present data.

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Observation of Protoplasmic Streaming by Laser-Light Scattering

Cited by 49 publications

References 6 publications

Hydrodynamic models of viscous coupling between motile myosin and endoplasm in characean algae.

Hydrodynamic models of viscous coupling between motile myosin and endoplasm in characean algae.

Light dependence of protoplasmic streaming in Nitella flexilis L. as measured by means of laser-velocimetry

Diffusive motions in living cytoplasm probed by laser Doppler microscopy

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