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Biomedical subjects

F Grinnell

Publications and source records attributed to F Grinnell.

14 recordsLinked to original sources
PubMed1979

Cell adhesion and spreading factor: chemical modification studies.

The purified fetal calf serum factor that promotes cell adhesion and spreading of baby hamster kidney cells on tissue culture substrata has been subjected to a variety of chemical modifications and then tested for activity. These studies have shown that modification of the carbohydrate portions of the factor by glycosidic enzymes or by periodate oxidation did not alter its ability to promote cell spreading. On the other hand, modification of some protein portions of the factor by proteolytic enzymes or by specific modification of -COOH groups, tyrosine residues, or tryptophan residues resulted in a marked inhibition of factor activity. Modification of protein -SH groups, -NH2 groups, or methionine residues did not affect factor activity. Control experiments indicate that the various modifications were directed at the activity of the factor and not its adsorption onto the substrata.

Adsorption↗
PubMed1979

Initial adhesion of human fibroblasts in serum-free medium: possible role of secreted fibronectin.

Experiments were carried out to test the hypothesis that the initial attachment and spreading of human fibroblasts in serum-free medium occurs to cell fibronectin which has been secretd spread on tissue culture substrata in serum-free medium in 60 min. When potential protein adsorption sites on the substratum were covered with bovine serum albumin before initial human fibroblasts attachment, their subsequent attachment to the substratum was prevented. When substratum adsorption sites were covered immediately after initial attachment, subsequent cell spreading was prevented. The distribution of fibronectin on human fibroblast surfaces during initial attachment and spreading was studied by indirect immunofluorescence analysis using a monospecific anti-cold-insoluble globulin antiserum. The initial appearance (10 min) of fibronectin was in spots over the entire cell surface. Concomitant with human fibroblast spreading, the random distribution of sites disappeared, and most fibronectin was subsequently observed in spots at the cell substratum interface (60 min). A fibrillar pattern of fibronectin appeared later (2-8 hr). The sites beneath the cells could be visualized as footprints on the substratum following treatment of the attached human fibroblasts with 0.1 M NaOH. A second fluorescence pattern of fibronectin secreted on the substratum was characterized by a diffuse halo around the cells and a very faint, diffuse staining elsewhere on the substratum. Another cell type (baby hamster kideny cells) was used to assay biologically for the presence or absence of the factor secreted by human fibroblasts on the substratum. Human fibroblasts were found to secrete an adhesion factor for baby hamster kidney cells into the substratum in a time- and temperature-dependent fashion, and immunological studies indicated that the factor secreted by human fibroblasts was cross-reactive with cold-in-soluble globulin, the plasma form of fibronectin. The conditioning factor secreted by the human fibroblasts was also found to be an attachment and spreading factor for human fibroblasts in experiments measuring human fibroblast adhesion to fibronectin footprints of human fibroblasts. Substratum-adsorbed cold-insoluble globulin was also found to be an attachment and spreading factor for human fibroblasts. Based upon the timing of appearance of conditioning factors on the substratum and the immunofluorescence patterns, it seems that the diffusely organized fibronectin on the substratum constitutes the sites to which cell attachment occurs. The bright spots of fibronectin that appear beneath the cells may represent fibronectin reorganization during cell spreading.

Animals↗
PubMed1979

The influence of cold insoluble globulin on platelet morphological response to substrata.

Light microscopic studies have been carried out on the attachment and morphological responses of washed human platelets in serum-free medium to fibrinogen-coated, collagen-coated and uncoated tissue culture plastic substrata. Platelets were observed to attach to the substratum, extend filipodia and undergo spreading. Subsequently, lysis of platelets occurred. On uncoated tissue culture plastic substrata, the addition of cold insoluble globulin to the incubations had no effect on the above morphological changes. On the other hand, on the protein coated substrata, there was very little platelet spreading or lysis without the addition of cold insoluble globulin.

Blood Platelets↗
PubMed1978

Attachment and spreading of baby hamster kidney cells to collagen substrata: effects of cold-insoluble globulin.

Studies have been carried out to determine the effects of cold-insoluble globulin (CIG) on the attachment and spreading of baby hamster kidney cells on various collagen substrata. Cell attachment to native collagen substrata occurred in the absence of CIG just as fast as attachment to dried collagen or gelatin substrata occurred in the presence of CIG. On the other hand, cell attachment to dried collagen or gelatin was markedly reduced in the absence of CIG. Cell spreading also occurred on native collagen in the absence of CIG; however, CIG was absolutely required for cell spreading to occur on dried collagen or gelatin. Finally, anti-CIG antiserum or lactoperoxidase treatment inhibited cell spreading on CIG-coated substrata but not on native collagen substrata. The data are discussed in terms of the interaction of fibroblasts with collagen in situ.

Cell Adhesion↗
PubMed1975

The distribution and mobility of anionic sites on the surfaces of baby hamster kidney cells.

The distribution and mobility of anionic sites on the surfaces of baby hamster kidney cells were studied by utilizing the multivalent ligand, polycationic ferritin, as a visual probe. Our observations revealed that anionic sites are distributed over the entire cell surface, with the highest density of sites being located on cell surface microextensions. Following the initial binding of polycationic ferritin to the surface of unfixed cells, the ligand-bound anionic sites redistributed by migrating from the surface of microextensions to the surface of the cell body. In 20 min, this migration resulted in a total clearing of anionic sites from the surface of microextensions concomitant with the formation of patches of anionic sites on the surface of the cell body. Polycationic ferritin-induced migration and patch formation of anionic sites was not prevented by 2,4-dinitrophenol, N-ethylmaleimide, colchicine, or cytochalasin B. However, the ligand-induced redistribution of cell surface anionic sites was prevented by prefixation of cells with glutaraldehyde.

Anions↗