380
J. T. DINGLE AND M. WEBB
hyaluronic acid and chondroitin sulphate turnover at different rates,
the half-life times of the hyaluronic acid and chondroitin sulphate
molecules being about 3-5 and 8 days respectively. Results obtained
by W e b b and Biggers (1961) and Lucy, Webb and Biggers (1961), on
the incorporation of
1 4
C-labelled glucose into amino sugars, purine
bases, and amino acids of the proteins, nucleic acids and mucopolysaccharides of embryonic chick-bone rudiments cultivated in a defined
medium, suggest that in culture the mucopolysaccharides turnover
more rapidly than other macromolecular components of the explants.
Work by Gross, Mathews and Dorfman (1960), however, in which the
chondromucoprotein was isolated from the costal cartilage of rats killed
at different times after the injection of
3 5
S 0 4
2 _ and (l1 4
C)-lysine
showed that the turnover rates of the chondroitin sulphate and protein
moieties were the same, and hence that the mucoprotein was metabolized as a unit. Further comparative studies of mucopolysaccharide
turnover in organ culture and in vivo would be of interest.
F. ENZYMIC DEGRADATION OF MUCOPOLYSACCHARIDES
IN CULTURE
The Tissue Culture system is probably ideally suited for study of the
relationship of the cell to its environment in a dynamic situation. The
cell can modify its environment in various ways: these include synthesis
and degradation of extracellular material. That cells and tissues in
culture are able to synthesize a variety of mucopolysaccharides has
been pointed out. Less work, however, has been done on the degradation of extracellular mucopolysaccharides and mucopolysaccharide
protein complexes in culture. Indeed, little is known of the ability
of tissue to modify its environment by the degradation of extracellular
material, although the release of bound hydrolyases from intracellular
particles (lysosomes) of organized tissues in culture under certain conditions has been demonstrated recently in this laboratory (Fell and
Dingle, 1963).
Most mucopolysaccharides occur in combination with protein, and
their release by treatment of tissues with proteolytic enzymes in vivo
has been demonstrated frequently (Tsaltas, 1958; McCluskey and
Thomas, 1958; Bryant, Leder and Stetten, 1958). This type of experiment has been applied successfully to organ cultures by Fell and Thomas
(1960), who, in an attempt to duplicate some of the effects of excess
vitamin A, added papain protease to cultures of embryonic bone
rudiments. This protease did not visibly degrade the plasma clot on
which the bone rudiments were grown, but induced extensive changes
in the extracellular material of cartilage of 7- and 13-day chick rudi-
J. T. DINGLE AND M. WEBB
hyaluronic acid and chondroitin sulphate turnover at different rates,
the half-life times of the hyaluronic acid and chondroitin sulphate
molecules being about 3-5 and 8 days respectively. Results obtained
by W e b b and Biggers (1961) and Lucy, Webb and Biggers (1961), on
the incorporation of
1 4
C-labelled glucose into amino sugars, purine
bases, and amino acids of the proteins, nucleic acids and mucopolysaccharides of embryonic chick-bone rudiments cultivated in a defined
medium, suggest that in culture the mucopolysaccharides turnover
more rapidly than other macromolecular components of the explants.
Work by Gross, Mathews and Dorfman (1960), however, in which the
chondromucoprotein was isolated from the costal cartilage of rats killed
at different times after the injection of
3 5
S 0 4
2 _ and (l1 4
C)-lysine
showed that the turnover rates of the chondroitin sulphate and protein
moieties were the same, and hence that the mucoprotein was metabolized as a unit. Further comparative studies of mucopolysaccharide
turnover in organ culture and in vivo would be of interest.
F. ENZYMIC DEGRADATION OF MUCOPOLYSACCHARIDES
IN CULTURE
The Tissue Culture system is probably ideally suited for study of the
relationship of the cell to its environment in a dynamic situation. The
cell can modify its environment in various ways: these include synthesis
and degradation of extracellular material. That cells and tissues in
culture are able to synthesize a variety of mucopolysaccharides has
been pointed out. Less work, however, has been done on the degradation of extracellular mucopolysaccharides and mucopolysaccharide
protein complexes in culture. Indeed, little is known of the ability
of tissue to modify its environment by the degradation of extracellular
material, although the release of bound hydrolyases from intracellular
particles (lysosomes) of organized tissues in culture under certain conditions has been demonstrated recently in this laboratory (Fell and
Dingle, 1963).
Most mucopolysaccharides occur in combination with protein, and
their release by treatment of tissues with proteolytic enzymes in vivo
has been demonstrated frequently (Tsaltas, 1958; McCluskey and
Thomas, 1958; Bryant, Leder and Stetten, 1958). This type of experiment has been applied successfully to organ cultures by Fell and Thomas
(1960), who, in an attempt to duplicate some of the effects of excess
vitamin A, added papain protease to cultures of embryonic bone
rudiments. This protease did not visibly degrade the plasma clot on
which the bone rudiments were grown, but induced extensive changes
in the extracellular material of cartilage of 7- and 13-day chick rudi-