Hydrodynamic properties and the shape of the molecules of the polysaccharide ficoll-400 in solution

Lavrenko, P. N.; Mikryukova, O.I.; Didenko, S. A.

doi:10.1016/0032-3950(86)90183-8

Cited by 24 publications

(32 citation statements)

References 20 publications

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“…The Mark-Houwink exponent a reported by Lavrenko (0.35) for Ficoll 400 is nearly identical with that measured here (0.36), despite the change in solvent from water to PBS (21). These results are also notable considering the interval of over two decades between these experiments, during which time the synthesis, separation, and purification of the commercially available product might have varied.…”

Section: Discussionsupporting

confidence: 89%

“…Lavrenko et al (21,22) published initial characterization data on Ficoll relating mass to intrinsic viscosity, sedimentation, and diffusion coefficient, but used techniques not easily available to glomerular physiologists. In brief, he measured translational diffusion in a cassette diffusometer, sedimentation in a centrifuge, and viscosity by a U-tube viscometer.…”

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confidence: 99%

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Size and conformation of Ficoll as determined by size-exclusion chromatography followed by multiangle light scattering

Fissell

Hofmann

Smith

et al. 2010

American Journal of Physiology-Renal Physiology

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Section: Discussionsupporting

confidence: 89%

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confidence: 99%

Size and conformation of Ficoll as determined by size-exclusion chromatography followed by multiangle light scattering

Fissell

Hofmann

Smith

et al. 2010

American Journal of Physiology-Renal Physiology

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“…Another possibility is that, at the high Ficoll concentrations used here, these polymers associate to form a matrix or gel within which the cells could gain traction. Earlier studies of the physical chemistry of Ficoll solutions show that, even at high concentrations, individual molecules have a diffusion coefficient typical of a molecule of that size (14). Thus the Ficoll solutions we use here have no extensive lattice.…”

Section: Discussionmentioning

confidence: 99%

Dictyostelium amoebae and neutrophils can swim

Barry

Bretscher

2010

Proc. Natl. Acad. Sci. U.S.A.

115

142

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Animal cells migrating over a substratum crawl in amoeboid fashion; how the force against the substratum is achieved remains uncertain. We find that amoebae and neutrophils, cells traditionally used to study cell migration on a solid surface, move toward a chemotactic source while suspended in solution. They can swim and do so with speeds similar to those on a solid substrate. Based on the surprisingly rapidly changing shape of amoebae as they swim and earlier theoretical schemes for how suspended microorganisms can migrate (Purcell EM (1977) Life at low Reynolds number. Am J Phys 45:3-11), we suggest the general features these cells use to gain traction with the medium. This motion requires either the movement of the cell's surface from the cell's front toward its rear or protrusions that move down the length of the elongated cell. Our results indicate that a solid substratum is not a prerequisite for these cells to produce a forward thrust during movement and suggest that crawling and swimming are similar processes, a comparison we think is helpful in understanding how cells migrate.cell migration | cell swimming | chemotaxis T he leading front of an animal cell migrating over a substratum is differentiated from the rest of the cell by several properties believed to be linked to how the cells migrate (1, 2). It is the main site of actin filament formation (3) whose polymerizing force may impinge on the membrane at the front of the cell to force it forward and so advance the cell's front (4-7). It is also the site of exocytosis of recycling membrane from the cell's internal pools (8) whose area could provide the surface membrane required for the cell to extend itself forward (9). Whatever the actual process, as a cell moves up a chemotactic gradient the information which the cell's surface receptors collect to steer the cell toward the source must determine which part of the cell's surface constitutes the front and must activate a motor there to extend the cell toward the source.Cell migration and chemotaxis generally are studied as the cells crawl over various solid substrates. The possibility that amoebae might swim arises from the observation that a mutant of Dictyostelium discoideum, sadA, which attaches poorly to a substrate, appears nevertheless to migrate normally and does so with an enhanced speed. The product of this gene is a plasma membrane protein which, when expressed in sadA, restores normal attachment and behavior (10). However, the extent to which the sadA strain is able to form transient attachments to a substratum is unclear. We therefore sought to discover whether Dictyostelium amoebae require a substrate upon which to move or whether they can swim. ResultsTo find whether cells might move in the absence of a substrate, we tried to find whether amoebae could migrate at a liquid-liquid interface or an air-water interface. With Christien Merrifield (of this laboratory), we found that these cells indeed can move at both interfaces, as had many others (e.g., ref. 11). However, the difficulty in in...

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“…[12][13][14] Conversion of surface hydroxyl groups to carboxyl groups offers the possibility of a series of negatively charged spheres of variable size and charge, which should be model solutes for the study of electrophoretic mobility. In this paper, we report on the preparation of carboxylated ficoll samples with sizes between those of dendrimers and latex particles.…”

Section: Introductionmentioning

confidence: 99%

Carboxylated Ficolls: Preparation, Characterization, and Electrophoretic Behavior of Model Charged Nanospheres

2006

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Carboxylated ficolls were prepared as model spherical colloids of variable charge and size, with radii ranging from 3.0 to 19.3 nm. Capillary electrophoresis (CE), electrophoretic light scattering (ELS), and potentiometric titration were used to determine mobilities as a function of pH, degree of ionization R, and surface potential ψ 0 . Measured mobilities typically display a plateau at high pH, corresponding to high R and ψ 0 , confirming the general nature of this effect for charged spheres, seen also for charged dendrimers and charged latex particles. This result is examined in the context of a discontinuity in mobility predicted by the Wiersema, O'Brien, and White (WOW) theory and a more recent primitive model electrophoresis (PME) theory, in which bound counterions are considered either as point charges or as hard spheres. While no mobility maximum can be determined as expected by these two theories, our data seem more to support Belloni's theoretical expectations on charged polymers and spheres. Here we explain the mobility plateaus in terms of counterions accumulated close to the surface (surface potential-determining ions) or within the shear plane (mobilitydetermining ions).

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Hydrodynamic properties and the shape of the molecules of the polysaccharide ficoll-400 in solution

Cited by 24 publications

References 20 publications

Size and conformation of Ficoll as determined by size-exclusion chromatography followed by multiangle light scattering

Size and conformation of Ficoll as determined by size-exclusion chromatography followed by multiangle light scattering

Dictyostelium amoebae and neutrophils can swim

Carboxylated Ficolls: Preparation, Characterization, and Electrophoretic Behavior of Model Charged Nanospheres

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