The mechanisms of glutaraldehyde-fixed sarcoma 180 ascites cell aggregation

Abstract

Sediment height analysis was employed to investigate the mechanisms of cell aggregation by glutaraldehyde-fixed sarcoma 180 ascites cells. The aggregation of these cells proceeds by a polymer bridging mechanism in which the surface molecules of one cell associate directly with the surface molecules of adjacent cells by nonbonding interactions. The ability of adhesive surface macromolecules to serve as polymer bridges is regulated by hydrophobic and coulombic interactions. Hydrophobic interactions are not significantly involved in polymer bridging per se, but instead appear to operate either intramolecularly or between adjacent molecules of the same cell surface, and regulate the conformation and ability of such molecules to form stable intermolecular associations with the surface adhesive molecules of a nearby cell. A disruption of these intrasurface hydrophobic interactions generally promotes cell aggregation. Coulombic forces generated by the fixed charges of surface molecules inhibit aggregation; their diminution by charge neutralization promotes aggregation. It is likely that coulombic repulsive forces regulate intramolecular associations, interactions between adjacent molecules arising from the same cell surface, and interactions between macromolecules arising from different cell surfaces. The actual forces which serve to aggregate two fixed cells are not hydrophobic, but have characteristics commonly attributed to hydrogen bonding. Ion-pairing does not seem to play a role in the aggregation of fixed cells under physiological electrolyte conditions, nor does disulfide bridging.

Intercellular adhesion mediated by human muscle neural cell adhesion molecule: effects of alternative exon use.

“…These rotational speeds corresponded to 30, 90, and 270 rpm. The least shear force placed upon the cells in this study was by using an assay in still medium similar to those previously described for a variety of other cell types (Weiss, 1968;Rosenberg et al, 1969;Garrod and Born, 1971;Skehan, 1975). Briefly, cells are allowed to collide under no forces other than those imposed by gravity on a cell suspension.…”

Glutaraldehyde fixation method for single‐cell lipid analysis by time‐of‐flight secondary ion‐mass spectrometry

“…The color following cytoplasmic staining ranges from blue to red depending on the charge state of the proteins . Because glutaraldehyde reacts with positively charged amino‐groups, positively charged methylene blue and azure B may have exhibited higher affinity toward fixed cells whose electronegativity on cell surface and cytosol was relatively increased compared with unfixed cells.…”

“…Chemical fixation with aldehydes is often necessary when examining biological samples to improve the preservation of specimens and to retain the microstructure as it leads to the formation of intermolecular crosslinking between proteins . Fixation is particularly useful when using clinical specimens as it allows preservation prior to the experiment so that examination can be performed at a later time and as it inactivates infectious agents such as viruses.…”

Assessment of different sample preparation routes for mass spectrometric monitoring and imaging of lipids in bone cells via ToF-SIMS

“…Chemical fixation is achieved by use of an aldehyde, e.g., glutaraldehyde (Glu) or "formalin"/paraformaldehyde (PFA), that cross-links the amine groups of (membrane) proteins via imine bonding 20,21 or methylene bridges, 22 respectively. It enables the analysis of samples in a dry state.…”