Changes in ribosome‐polyribosome balances in chick muscle cells during tissue dissociation, development in culture, and exposure to simplified culture‐medium

Abstract

The populations of polyribosomes, monomeric ribosomes, and ribosomal subunits are described from the time of tissue explantation to the time of complete muscle differentiation in primary cultures of chick muscle cells. There is extensive degradation of polyribosomes, and a net loss of ribosomes recovered, as cells of embryonic muscle are dissociated with proteolytic enzymes. The cells rapidly restore a high polysome:monomeric ribosome ratio. This recovery of the polyribosome population occurs before there is any detectable net increase in ribosome number. Ribosome production begins after a lag of approximately 15 hours in culture. Number of ribosomes/cell triples by 60 hours, at which time cell fusion (myotube formation) is complete. Unlike developing muscle in vivo, cultured cells have a very reduced pool of monomeric ribosomes. Medium simplification experiments done with fully differentiated cultures show, however, that monomers accumulate during starvation. These monomers reassociate to form polyribosomes during medium replenishment. Subunit complements are maintained at a constant level regardless of nutritional conditions. These features of cultured muscle are discussed as possible tools for further study of muscle development.

Polymer-Coated Surface as an Enzyme-Free Culture Platform to Improve Human Mesenchymal Stem Cell (hMSC) Characteristics in Extended Passaging

“…The exposure of the cell to proteolytic enzymes such as trypsin-EDTA in a repetitive manner results in the degradation of plasma membrane proteins and glycoproteins, and often causes serious internal cell damage including the degradation of polyribosomes. , The damaged surface protein aggravates the healthiness of cells by reducing the viability and proliferation capacity during the continuous in vitro expansion. The preservation of the structural integrity of cells is particularly important for enhancing the differentiation potential of hMSCs in clinical applications.…”

Control of Chondrogenic Expression in Mesodermal Cells of Embryonic Chick Limb

“…(ii) Different cell types within the limb mesoderm exhibit different survival characteristics after trypsinization. The myogenic phenotype seems to be particularly sensitive to trypsin (21), and a high proportion of these cells may be damaged irreversibly and fail to thrive. (iii) Although chick mesodermal cells have been exposed to large numbers of compounds known to produce toxic effects in vivo, none of these compounds has potentiated chondrogenic activity like 3-acetylpyridine.…”

Enzyme-passage free culture of mouse embryonic stem cells on thermo-responsive polymer surfaces

“…A common method employed requires ESC colonies to be enzymatically dissociated from the surface, usually with trypsin, to obtain individual cells which can then be plated onto fibroblast feeder layers or gelatin treated substrates for further expansion. Enzymatic passaging has been reported to injure mammalian cells internally via degradation of polyribosomes 7 as well as causing damage to the cell surface; 8 both injuries could significantly hinder their utility for clinical applications. Besides the risk of contamination by adventitious infectious agents, human ESCs can incorporate and express immunogenic molecules when exposed to animal products in culture (e.g.…”