title: Inaccessibility of certain Ricinus lectin binding sites due to the increase in hyaluronic acid during chick embryo development.
abstract: Chick embryo fibroblasts constitute a useful model for investigating cell surface differentiation using Ricinus lectin as a marker. Fibroblasts from 8-day chick embryos had two classes of Ricinus lectin binding sites, whereas those from 16-day embryos displayed only one class. Hyaluronidase treatment of fibroblasts from 8-day embryos had no effect on their capacity to bind Ricinus lectin; however after this treatment, 16-day cells resembled 8-day cells since the former also exhibited two classes of lectin-binding sites. Treatment with hyaluronidase released 2-5 times more hyaluronic acid from the older cells than from the younger cells. The same hyaluronidase treatment did not change the number of 8-day cells detached by trypsin from the substrate, but increased the number of detached 16-day cells. These observations suggest (i) that the greater adhesiveness to the substrate of the 16-day cells might be due to the presence on the cell surface of a larger amount of glycosaminoglycans at 16 days than at 8 days, and (ii) that the increased accumulation of hyaluronic acid on the cell surface might be involved in an alteration in the cell membrane during differentiation.
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002642:Chick Embryo / Q000254:growth & development*; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D006820:Hyaluronic Acid / Q000378:metabolism*; D006821:Hyaluronoglucosaminidase / Q000494:pharmacology; D037102:Lectins / Q000378:metabolism; D037121:Plant Lectins; D011975:Receptors, Mitogen / Q000378:metabolism*
chemical_list: D037102:Lectins; D037121:Plant Lectins; D011975:Receptors, Mitogen; C017707:Ricinus communis agglutinin-1; C032650:Ricinus communis lectin receptor; D006820:Hyaluronic Acid; D006821:Hyaluronoglucosaminidase